To perform the balloon expulsion test, a catheter with a balloon on its tip is introduced into the patient's anorectum. [ 5 ]  The balloon is then distended to 50ml with water. [ 5 ]  Patients are then instructed to transfer from lying on their side to sitting on a toilet. [ 5 ]  Next, patients are asked to push out the balloon as if they are defecating. [ 5 ]  The time it takes for the expulsion of the balloon is then recorded. [ 5 ]


The anal resting pressure is the recorded pressure within the anus during muscle relaxation. [ 6 ]  After insertion of the catheter, a short amount of time is allowed for the muscles to relax. Afterwards, pressures are recorded over 60 seconds. [ 5 ]  The  maximum  resting pressure is the highest pressure reached during this time period, while the  mean  resting pressure is the average pressure during this time period. In healthy individuals, women, especially older women, have an average lower anal resting pressures than men. [ 6 ]


The anal squeeze pressure is the recorded pressure within the anus during a voluntary contraction of the  external anal sphincter . [ 6 ]  Similar to resting pressures, squeeze pressures in healthy women are lower than healthy men. [ 6 ]  If using high-definition anorectal manometry, asymmetry in squeeze pressures can also be measured. [ 6 ]


During  defecation , the pressure in the anorectum should increase while the  external anal sphincter  should relax. If the pressure difference during defecation does not increase sufficiently, it may indicate poor propulsive force. [ 6 ] [ 14 ]  Additionally, inadequate relaxation of the sphincter during defecation is another abnormal finding. [ 6 ]  Another method to assess changes during defecation is to calculate an anorectal gradient (or defecation index) in one of two ways. [ 14 ]  The anorectal gradient is either calculated as a difference (rectal pressure - anal pressure) or as a  ratio  (rectal pressure / anal pressure). [ 14 ]  A positive difference or a ratio over 1 indicates normal findings. [ 14 ]  Abnormal findings on manometry does not definitively indicate illness as a significant number of healthy individuals have been found to have abnormal results. [ 6 ] [ 14 ]  Values recorded during a defecation trial are influenced by a number of factors including the degree of patient involvement in defecation efforts. [ 6 ]


In healthy individuals, in the process of defecating, the  internal anal sphincter  will  reflexively  relax. The lack of a  rectoanal inhibitory reflex  may indicate either the absence or the non-functionality of certain muscle or nerve structures involved in proper defecation. [ 3 ] [ 6 ]


Patients are assessed on their anorectal sensory perception via the inflation of a balloon. As the balloon is inflated, its volume is recorded at certain milestones: [ 5 ]  initial sensation of the equipment, start of the sensory urge to defecate and the point of maximum discomfort. [ 6 ] [ 3 ]  An increased level of sensation has been noted in disorders such as  fecal incontinence , while a decreased level of sensation has been seen in individuals with  dyssynergic defecation . [ 3 ]


As part of the 2020 IAPWG consensus manuscript, the group published the newly created London Classification for Disorders of Anorectal Function which aimed to standardize the interpretation of anorectal manometry findings. [ 5 ] [ 7 ]  The London Classification divided disorders into 4 parts:


Under each part, there are a list of diagnosis that are made based on manometry findings. For example, under part 2 (Disorders of anal tone and contractility), listed manometric diagnoses include: anal hypotension, anal hypertension, anal hypercontractility and combined anal hypertension and hypercontractility. [ 7 ]  Findings are also divided into: major findings, minor findings and inconclusive findings. [ 7 ]  Major findings are findings that are not present in healthy patient such as rectoanal areflexia, [ 7 ]  Minor findings are findings that are more commonly found in patients with anorectal disease compared to healthy patients, while inconclusive findings are findings that may be present in both groups. [ 7 ]


Centers rely on published data sets from healthy volunteers to evaluate test findings. [ 4 ]  However, the lack of standardization in equipment usage and procedural protocol, can in certain cases, impact the ability to determine what may be considered normal or abnormal values. [ 4 ]  This is further complicated by the limited amount of data on the impact of different epidemiological characteristics (such as age or gender) on said values. [ 4 ]  For an individual patient, findings on anorectal manometry, alone, does not dictate management. [ 7 ]  In addition to correlating manometry findings with clinical findings, as part of a diagnostic or evaluatory workup, the use of anorectal manometry may be complemented with other diagnostic tests such as  endoanal ultrasound ,  defecography  or gut transit studies. [ 7 ]  High resolution anorectal manometry also experiences pressure drift, variable linear changes in pressure readings over time, that could impact the clinical value of manometry findings in some specific situations. [ 6 ]


An  anoscopy  is a  medical examination  using a small, rigid, tubular instrument called an anoscope (also called a  rectal speculum ).  This is inserted a few inches into the  anus  in order to evaluate problems of the  anal canal . Anoscopy is used to diagnose  hemorrhoids ,  anal fissures  (tears in the lining of the anus), and some  cancers . [ 1 ] [ 2 ]


This test is usually done in a doctor's office. The patient is required to remove their underwear, and must either lie on their side on top of an examining table, with their knees bent up towards the chest, or bend forward over the table. The anoscope is 3 to 4 inches long and the width of an average-to-large bowel movement. The doctor will coat the anoscope with a lubricant and then gently push it into the anus and rectum. The doctor may ask the patient to "bear down" or push as if they were going to have a bowel movement, and then relax. This helps the doctor insert the anoscope more easily and identify any bulges along the lining of the rectum.


By shining a light into this tube, the doctor will have a clear view of the lining of the lower rectum and anus. The anoscope is pulled out slowly once the test is finished.


The patient will feel pressure during the examination, and the anoscope will make one feel as if they were about to have a bowel movement. This is normal, however, and many patients do not feel pain from anoscopy.


Anoscopy will permit  biopsies  to be taken, and is used when ligating prolapsed hemorrhoids. It is used in the treatment of warts produced by  HPV .


The procedure is done on an outpatient basis.


A  cholecystoenterostomy  is a surgical procedure in which the  gall bladder  is joined to the  small intestine . It is performed in order to allow bile to pass from the  liver  to the  intestine  when the  common bile duct  is obstructed by an irremovable cause. [ 1 ]


A  cul-de-sac hernia  (also termed a  peritoneocele ) is a  herniation  of  peritoneal  folds into the  rectovaginal septum  (in females), [ 2 ]  or the  rectovesical septum  (in males). The herniated structure is the  recto-uterine pouch  (pouch of Douglas) in females, [ 2 ]  or the  rectovesical pouch  in males. The hernia descends below the proximal (upper) third of the vagina in females, [ 2 ]  or, according to another definition, below the pubococcygeal line (PCL). [ 3 ] [ note 1 ]


According to a consensus statement by the USA, Australia and the UK, [ note 2 ]  a cul-de-sac hernia / peritoneocele is defined as "a protrusion of the peritoneum between the rectum and vagina that does not contain any abdominal viscera" (organs). [ 4 ]  An enterocele is defined as "a protrusion of the peritoneum between the rectum and vagina containing the small intestine." [ 4 ]  A sigmoidocele is defined as "a protrusion of the peritoneum between the rectum and vagina that contains the sigmoid colon." [ 4 ]  An omentocele is defined as "a protrusion of the omentum between the rectum and the vagina." [ 4 ]  As such, peritoneocele, enterocele, sigmoidocele, and omentocele could be considered as types of cul-de-sac hernia. [ 3 ] [ 4 ]


This hernia is so named because it is a herniation of the recto-uterine pouch (pouch of Douglas), which is also sometimes called the "cul-de-sac". This is the pocket formed by the reflection of the peritoneum from the rectum and the posterior wall of the uterus. The equivalent structure in males is the rectovesical pouch, which is the pocket formed by the reflections of the peritoneum from the rectum to the male bladder. In terms of pelvic organ prolapse, a cul-de-sac hernia is located in the posterior compartment of the pelvis. [ 5 ]


A true cul-de-sac hernia contains only  omental  fat, and often  intraperitoneal liquid. [ 6 ]  If the hernia contains omentum, sometimes the term "omentocele" is used. [ 7 ]  If the cul-de-sac hernia contains loops of small bowel, the term  enterocele  is used. [ 2 ]  If it contains sigmoid colon, the term  sigmoidocele  is used. [ 2 ]  It has been suggested that the terms enterocele and sigmoidocele are inaccurate, since hernias are usually named according to location and not according to contents. [ 8 ]  However, the terms are in widespread use. [ 8 ]  As such, peritoneocele, enterocele, sigmoidocele, and omentocele could be considered as types of cul-de-sac hernia. [ 3 ] [ 4 ]


Cul-de-sac hernias may be classified as rectal, septal, or vaginal depending on the structure they herniate into. Rectal cul-de-sac hernias herniate into an internal or external  rectal prolapse . Septal cul-de-sac hernias herniate into the recto-vaginal septum (rectovesical septum in males). Vaginal cul-de-sac hernias bulge into the vagina itself. Combinations of these types are also possible. [ 6 ]


Severity of the hernia may be classed as first degree if it is above the pubococcygeal line, second degree if it is below the pubococcygeal line but above the ischiococcygeal line, [ note 3 ]  or third degree if it is below the ischiococcygeal line. [ 9 ]  Severity may also be graded according the distance between the pubococcygeal line and the lowest point of the sac as follows: small (less than 3 cm), moderate (3–6 cm) or large (more than 6 cm). [ 9 ]


Cul-de-sac hernias may also be classified as primary and secondary. Primary cul-de-sac hernias are associated with factors such as  multiparity , old age, lack of elasticity,  obesity ,  constipation , and increased abdominal pressure are present. [ 8 ]  Secondary cul-de-sac hernias are those which develop after gynecologic procedures, especially after vaginal hysterectomy. [ 8 ]


Another classification of cul-de-sac hernias is internal, meaning those that are only visible on defecography, or external, which are associated with a clinically visible rectocele or rectal prolapse. [ 4 ]


Symptoms are variable, and depend on the exact location and severity of the hernia. [ 10 ]  Possible symptoms include:


Cul-de-sac hernias are the most difficult to diagnose during physical examination, and to distinguish from anterior  rectocele  or enterocele. [ 2 ]  Furthermore, rectocele and cul-de-sac hernia may occur together. [ 3 ]  Combined vaginal and rectal digital palpation may be used (examiner's thumb in vagina, index finger in anal canal). [ 11 ]  The peritoneal sac containing omentum may be palpable between the thumb and index finger. [ 11 ]  The prolapse may be detectable at the upper posterior vaginal wall during  Valsalva's maneuver . [ 11 ]


Imaging which may be used to detect cul-de-sac hernia includes standard  defecography , magnetic resonance defecography and  dynamic transperineal ultrasound . [ 5 ]  Cul-de-sac hernias usually only appear on such imagining at the end of the simulated defecation, and require complete or near complete evacuation of the rectum before they are visible. [ 3 ]  This feature may distinguish cul-de-sac hernia from rectocele. [ 1 ]  However, a large rectocele that retains contrast medium may hide a cul-de-sac hernia. [ 3 ]  Cul-de-sac hernia (peritoneocele / omentocele) may appear on fluoroscopic defecography as an un-opacified mass which deforms the anterior border of the rectum and the posterior border of the vagina, with widening of the recto-vaginal space in between. [ 1 ]  On magnetic resonance defecography, the vagina and rectum may appear clearly "splayed" apart. [ 1 ]


Risk factors include prior  hysterectomy  and  urethropexy  because of the damage caused to the  rectovaginal fascia . [ 2 ]  Hysterectomy also increases the size of the pouch of Douglas. [ 1 ]


Defecography  (also known as proctography, defecating/defecation proctography, evacuating/evacuation proctography or dynamic rectal examination) is a type of medical  radiological  imaging in which the mechanics of a patient's  defecation  are visualized in real time using a  fluoroscope . [ 1 ]  The anatomy and function of the anorectum and  pelvic floor  can be dynamically studied at various stages during defecation. [ 2 ]


Defecating proctography was pioneered in 1945, during  World War II . The procedure gained popularity at this time in the midst of an outbreak of  whipworm , which is known to cause  rectal prolapse . [ 3 ]  It has since become used for diagnosis of various anorectal disorders, including  anismus  and other causes of  obstructed defecation .


It has fallen out of favor due to inadequate training in the technique. It is now only performed at a few institutions. Many radiology residents refer to the procedure as the "Def Proc", "Defogram", or "Stool Finale". [ citation needed ]


Defecography may be indicated for the following reasons:


Specifically, defecography can differentiate between anterior and posterior  rectocele . [ 4 ]  Also, in external  rectal prolapse  that was not directly visualized during examination, this radiographic projection will demonstrate its presence.


In females, pre-procedural preparation involves smearing a small amount of  barium   contrast agent  in the vagina, which will help to identify if anterior  rectocele ,  enterocele  or  sigmoidocele  is present.


The technique itself involves the insertion of a  caulking gun  device into the rectum with a subsequent manual infusion of barium paste until there is adequate distension. The patient is then transferred to a portable plastic commode which is situated next to a fluoroscope which records the defecation. Positioning of the X-ray camera is of paramount importance as visualization of the buttocks, rectal vault, and lower pelvis is critical.


Anatomical and physiological parameters that can be objectively measured by this investigation include: [ 2 ]


Conditions which may be demonstrated include: [ 2 ]


The rectum may be seen to prolapse, whether internally or externally. There can be difficulty differentiating between internal intussusception and a normal rectal fold. The thickness of the intussusception is half the width of the intussusception (the intussusception is a doubled over layer of rectal wall). This is most likely to be seen during straining.


Cinedefecography is a technique that is an evolution of defecography. The defecation cycle is recorded as a continuous series rather than individual still radiographs. [ 2 ]  More recent techniques involve the use of advanced, cross-sectional imaging modalities such as  magnetic resonance imaging . [ 6 ]  This is known as dynamic pelvic MRI, or MRI proctography. [ 2 ]  The MRI proctography also called MRI defecography is not as efficient as conventional X-ray defecography for some problems. [ citation needed ]


Diseases of the Colon & Rectum  is a monthly  peer-reviewed   medical journal  covering  colorectal surgery . It was established in 1958 and is published by  Lippincott Williams and Wilkins  on behalf of the  American Society of Colon and Rectal Surgeons , of which it is the official journal. The  editor-in-chief  is Susan Galandiuk ( University of Louisville ). According to the  Journal Citation Reports , the journal has a 2016  impact factor  of 3.519. [ 1 ]


Endodermal sinus tumor  ( EST ) is a member of the  germ cell tumor  group of  cancers . [ 1 ]  It is the most common testicular tumor in children under three, [ 2 ]  and is also known as  infantile embryonal carcinoma . This age group has a very good prognosis. In contrast to the pure form typical of infants, adult endodermal sinus tumors are often found in combination with other kinds of germ cell tumor, particularly  teratoma  and  embryonal carcinoma . While pure teratoma is usually  benign , endodermal sinus tumor is  malignant .


Causes for this cancer are poorly understood. [ citation needed ]


The  histology  of EST is variable, but usually includes malignant endodermal cells. These cells secrete  alpha-fetoprotein  (AFP), which can be detected in tumor tissue,  serum ,  cerebrospinal fluid ,  urine  and, in the rare case of fetal EST, in  amniotic fluid . When there is incongruence between  biopsy  and AFP test results for EST, the result indicating presence of EST dictates treatment. [ 3 ]  This is because EST often occurs as small "malignant foci" within a larger tumor, usually  teratoma , and biopsy is a sampling method; biopsy of the tumor may reveal only teratoma, whereas elevated AFP reveals that EST is also present. GATA-4, a  transcription factor , also may be useful in the diagnosis of EST. [ 4 ]


Diagnosis of EST in  pregnant women  and in  infants  is complicated by the extremely high levels of AFP in those two groups. Tumor surveillance by monitoring AFP requires accurate correction for gestational age in pregnant women, and age in infants. In pregnant women, this can be achieved simply by testing  maternal serum AFP  rather than  tumor marker AFP . In infants, the tumor marker test is used, but must be interpreted using a reference table or graph of normal AFP in infants. [ medical citation needed ]


EST can have a multitude of morphologic patterns including: reticular, endodermal sinus-like, microcystic, papillary, solid, glandular, alveolar, polyvesicular vitelline, enteric and hepatoid. [ medical citation needed ]


Schiller–Duval bodies  on  histology  are  pathognomonic  and seen in the context of the endodermal sinus-like pattern. Rarely, it can be found in the vagina. [ 6 ] [ 7 ]


Most treatments involve some combination of  surgery  and  chemotherapy . Treatment with  cisplatin ,  etoposide , and  bleomycin  has been described. [ 8 ]  Before modern chemotherapy, this type of neoplasm was highly lethal, but the prognosis has significantly improved since then. [ citation needed ]  When endodermal sinus tumors are treated promptly with surgery and chemotherapy, fatal outcomes are exceedingly rare. [ 9 ]


Germ cell tumor  ( GCT ) is a  neoplasm  derived from the  primordial germ cells . [ 1 ]  Germ-cell tumors can be  cancerous  or  benign . Germ cells normally occur inside the  gonads  ( ovary [ 2 ]  and  testis ).  GCTs that originate outside the gonads may be  birth defects  resulting from errors during  development  of the  embryo .


GCTs are classified by their  histology , [ 4 ]  regardless of location in the body. However, as more information about the genetics of these tumors become available, they may be classified based on specific gene mutations that characterize specific tumors. [ 5 ]  They are broadly divided in two classes: [ 6 ]


The two classes reflect an important clinical difference. Compared with germinomatous tumors, nongerminomatous tumors tend to grow faster, have an earlier mean age at time of diagnosis (around 25 years versus 35 years, in the case of  testicular cancers ), and have a lower five-year survival rate.  The survival rate for germinomatous tumors is higher in part because these tumors are very sensitive to radiation, and they also respond well to chemotherapy.  The prognosis for nongerminomatous tumours has improved dramatically, however, due to the use of platinum-based chemotherapy regimens. [ 7 ]


Mixed germ cell tumors occur in many forms.  Among these, a common form is teratoma with endodermal sinus tumor.


Teratocarcinoma refers to a germ cell tumor that is a mixture of  teratoma  with  embryonal carcinoma , or with  choriocarcinoma , or with both. [ 9 ]   This kind of mixed germ cell tumor may be known simply as a teratoma with elements of embryonal carcinoma or choriocarcinoma, or simply by ignoring the teratoma component and referring only to its malignant component:  embryonal carcinoma and/or choriocarcinoma. They can present in the  anterior mediastinum . [ citation needed ]


Some investigators suggest that this distribution arises as a consequence of abnormal migration of germ cells during embryogenesis. Others hypothesize a widespread distribution of germ cells to multiple sites during normal embryogenesis, with these cells conveying genetic information or providing regulatory functions at somatic sites. [ citation needed ]


Extragonadal GCTs were thought initially to be isolated  metastases  from an undetected primary tumor in a  gonad , but many germ cell tumors are now known to be   congenital  and originate outside the gonads.  The most notable of these is  sacrococcygeal teratoma , the single most common tumor diagnosed in babies at birth. [ citation needed ]


Of all anterior mediastinal tumors, 15–20% are GCTs of which about 50% are benign teratomas. [ 10 ]  Ovarian teratomas may be associated with  anti-NMDA receptor encephalitis . [ 11 ]


Despite their name, GCTs occur both within and outside the  ovary  and  testis . They are found in: [ citation needed ] }


In females, GCTs account for 30% of ovarian tumors, but only 1 to 3% of  ovarian cancers  in  North America . In younger women, they are more common, thus in patients under the age of 21, 60% of ovarian tumors are of the  germ-cell type , and up to one-third are  malignant . In males, GCTs of the testis occur typically after puberty and are malignant ( testicular cancer ).  In  neonates ,  infants , and  children  younger than 4 years, most are  sacrococcygeal teratomas . [ citation needed ]


Males with  Klinefelter syndrome  have a 50 times greater risk of GSTs. [ 12 ]   In these persons, GSTs usually contain nonseminomatous elements, present at an earlier age, and seldom are gonadal in location. [ medical citation needed ]


Women with benign GCTs such as  mature teratomas  (dermoid cysts) are cured by  ovarian cystectomy  or  oophorectomy . [ 13 ]  In general, all patients with malignant GCTs have the same staging surgery that is done for  epithelial ovarian cancer . [ 14 ]  If the patient is in her reproductive years, an alternative is unilateral  salpingoophorectomy , while the uterus, the ovary, and the fallopian tube on the opposite side can be left behind. This is not an option when the cancer is in both ovaries. If the patient has finished having children, the surgery involves complete staging, including salpingoophorectomy on both sides, as well as  hysterectomy . [ 13 ]


Patients with germ-cell cancer often need to be treated with combination  chemotherapy  for at least three cycles, but female patients with early-stage disease may not require this treatment. [ 15 ]  The  chemotherapy regimen  most commonly used in GCTs is called PEB (or BEP), and consists of  bleomycin ,  etoposide , and a  platinum-based antineoplastic  ( cisplatin ). [ 13 ]  Targeted treatments, such as immunotherapy, hormonal therapy and kinase inhibitors, are being evaluated for tumors that do not respond to chemotherapy. [ 16 ]


The 1997 International Germ Cell Consensus Classification [ 17 ]  is a tool for estimating the risk of relapse after treatment of malignant germ-cell tumor.


A small study of ovarian tumors in girls [ 18 ]  reports a correlation between  cystic  and benign tumors, and conversely, solid and malignant tumors.  Because the cystic extent of a tumor can be estimated by ultrasound, MRI, or CT scan before surgery, this permits selection of the most appropriate surgical plan to minimize risk of spillage of a malignant tumor. [ citation needed ]


Access to appropriate treatment has a large effect on outcome.  A 1993 study of outcomes in Scotland found that for 454 men with nonseminomatous (nongerminomatous) GCTs diagnosed between 1975 and 1989, five-year survival increased over time and with earlier diagnosis.  Adjusting for these and other factors, survival was 60% higher for men treated in a cancer unit that treated the majority of these men,  though the unit treated more men with the worst prognosis. [ 19 ]


Choriocarcinoma  of the testicles has the worst prognosis of all germ-cell cancers. [ 20 ]


A  gonadoblastoma  is a complex  neoplasm  composed of a mixture of  gonadal  elements, [ 1 ]  such as large primordial  germ cells , immature  Sertoli cells  or  granulosa cells  of the  sex cord , and gonadal  stromal cells . Gonadoblastomas are by definition benign, but more than 50% have a co-existing  dysgerminoma  which is malignant, and an additional 10% have other more aggressive malignancies, and as such are often treated as malignant. [ 2 ]


Gonadoblastoma is most often associated with an abnormal chromosomal  karyotype , gonadal  dysgenesis , or the presence of a  Y chromosome  in over 90% of cases. Gonadoblastoma has been found in association with  androgen insensitivity syndrome ,  mixed gonadal dysgenesis  and  Turner syndrome , especially in the presence of Y chromosome-bearing cells. [ 3 ] [ 4 ]  Women with Turner syndrome whose karyotype includes a Y chromosome (as in 45,X/46,XY mosaicism) are at increased risk for gonadoblastoma. Because of the risk of gonadoblastoma, individuals with Turner syndrome with detectable Y chromosome material (Mosaic Turner syndrome) should have their gonads prophylactically removed. In a population-based study, the cumulative risk for women with Turner syndrome and Y chromosome material was 7.9 percent by age 25 years. [ 5 ]


Gonadoblastomas can contain elements of both germ cells and gonadal stroma. [ 6 ]


Formerly, gonadoblastoma was sometimes regarded as a subset of  dysgerminoma . In modern literature, it is sometimes considered to progress to dysgerminoma. [ 7 ]


Standard treatment would include surgical exploration via  laparotomy .  Laparoscopy  may be an option if the surgeon is particularly skilled in removing ovarian neoplasms via laparoscopy intact. If the diagnosis of gonadoblastoma is certain, a bilateral  salpingo-oophorectomy  (BSO) should be performed to remove both the primary tumor and the dysgenic contralateral ovary. If uninvolved, the  uterus  should be left intact. Modern reproductive endocrinology technology allows patients post BSO to achieve pregnancy via in-vitro fertilization ( IVF ) with a donor egg. [ citation needed ]


Goodsall's rule  relates the external opening (in the perianal skin) of an  anal fistula  to its internal opening (in the anal canal). It states that if the perianal skin opening is posterior to the transverse anal line, the fistulous tract will open into the anal canal in the midline posteriorly, sometimes taking a curvilinear course. A perianal skin opening anterior to the transverse anal line (within 3cm radius) is usually associated with a radial fistulous tract but if it's beyond the 3 cm radius it will take a curvilinear course and open in the midline posterioly. [ 1 ]


Or in more direct terms, it means that anterior-opening fistulas tend to follow a simple, direct course if it is within the 3cm radius, beyond which it takes a curving path and opens in poster midline. The posterior-opening fistulas may follow a devious, curving path with some even being horseshoe-shaped before opening in the posterior midline. [ 2 ]


Fistulas  can be described as  anterior or posterior  relating to a line drawn in the  coronal plane  across the  anus , the so-called transverse anal line. Anterior fistulas will have a direct track into the anal canal. Posterior fistulas will have a curved track with their external opening lying in the posterior midline of the  anal canal . An exception to the rule are anterior fistulas lying more than 3.75 cm from the anus, which may have a curved track (similar to posterior fistulas) that opens into the posterior midline of the anal canal.


According to a study on patients undergoing operations for cryptoglandular anal fistulas, 92.9% of fistulas within 1.5 cm followed the Goodsall rule, whereas only 47.4% followed it beyond 3.6 cm. [ 3 ]


In situations where there are multiple anal fistulae, the course would be similar to that of posterior-opening fistulae because of branching and communication between these openings. [ citation needed ]


The investigation of choice for anal fistulas is  magnetic resonance imaging  (MRI). Fistulograms can be used to demonstrate the track of the fistula.


Goodsall's rule is named after  David Henry Goodsall  who described it in 1900.


An  imperforate anus  or  anorectal malformations  ( ARMs ) are  birth defects  in which the  rectum  is malformed. ARMs are a spectrum of different congenital anomalies which vary from fairly minor  lesions  to complex anomalies. [ 1 ]  The cause of ARMs is unknown; the genetic basis of these anomalies is very complex because of their anatomical variability. In 8% of patients, genetic factors are clearly associated with ARMs. [ 2 ]   Anorectal malformation  in  Currarino syndrome  represents the only association for which the gene  HLXB9  has been identified. [ clarification needed ] [ 1 ] [ 3 ]


There are other forms of anorectal malformations though imperforate anus is most common. Other variants include  cloacal malformation , rectal atresia, rectal stenosis, and anterior ectopic anus. [ 4 ] [ 5 ]  This form is more commonly seen in females and presents with constipation. [ 6 ]


There are several forms of imperforate anus and anorectal malformations. The new classification is in relation of the type of associated  fistula . [ 7 ]


The Wingspread classification was in low and high anomalies: [ citation needed ]


Imperforate anus is usually present along with other birth defects— spinal  problems,  heart  problems,  tracheoesophageal fistula ,  esophageal atresia ,  renal  anomalies and  limb  anomalies are among the possibilities, collectively being called the  VACTERL association . [ 8 ]


Imperforate anus is associated with an increased incidence of some other specific anomalies as well, together being called the  VACTERL association . [ citation needed ]


Other entities associated with an imperforate anus are trisomies 18 and 21, the  cat-eye syndrome  (partial  trisomy  or  tetrasomy  of a maternally derived  chromosome 22 ),  Baller–Gerold syndrome ,  Currarino syndrome ,  caudal regression syndrome ,  FG syndrome ,  Johanson–Blizzard syndrome ,  McKusick–Kaufman syndrome ,  Pallister–Hall syndrome ,  short rib–polydactyly syndrome type 1 ,  Townes–Brocks syndrome ,  13q deletion syndrome ,  urorectal septum malformation sequence  and the  OEIS complex  ( omphalocele ,  exstrophy  of the  cloaca , imperforate anus, spinal defects). [ citation needed ]


When an infant is born with an anorectal malformation, it is usually detected quickly as it is a very obvious defect. Doctors will then determine the type of birth defect the child was born with and whether or not there are any associated malformations. Determining the presence of any associated defects during the newborn period in order to treat them early may avoid further  sequelae . There are two main categories of anorectal malformations: those that require a protective  colostomy  and those that do not. The decision to open a colostomy is usually taken within the first 24 hours of birth. [ citation needed ]


Sonography  can be used to determine the type of imperforate anus. [ 9 ]


Imperforate anus usually requires immediate  surgery  to open a passage for  feces  unless a  fistula  can be relied on until corrective surgery takes place. Depending on the severity of the imperforate, it is treated either with a perineal  anoplasty [ 10 ]  or with a  colostomy .


While many surgical techniques to definitively repair anorectal malformations have been described, the posterior sagittal approach (PSARP) has become the most popular. It involves dissection of the perineum without entry into the abdomen and 90% of defects in boys can be repaired this way. [ citation needed ]


With a high lesion, many children have problems controlling bowel function and most also become  constipated . With a low lesion, children generally have good bowel control, but they may still become constipated. For children who have a poor outcome for continence and constipation from the initial surgery, further surgery to better establish the angle between the anus and the rectum may improve continence and, for those with a large rectum, surgery to remove that dilated segment may significantly improve the bowel control for the patient.  An antegrade enema mechanism can be established by joining the appendix to the skin (Malone stoma); however, establishing more normal anatomy is the priority. [ citation needed ]


Imperforate anus has an estimated incidence of 1 in 5,000 births. [ 11 ] [ 12 ]  It affects boys and girls with similar frequency. [ 13 ]   However, imperforate anus will present as the low version 90% of the time in females and 50% of the time in males.


Imperforate anus is an occasional complication of  sacrococcygeal teratoma . [ 14 ]


7th-century  Byzantine  physician  Paulus Aegineta  described a surgical treatment for imperforate anus for the first time. [ 15 ]  10th-century  Persian  physician  Haly Abbas  was the first to highlight preserving the  sphincter muscles  throughout the surgery and the prevention of strictures with a  stent . [ 15 ]  He has reported the use of wine for wound care in this surgery. Some reports of children surviving this surgery are available from the early  medieval Islamic era . [ 16 ]


A  keyhole defect  is a term used in medicine and in the  forensic sciences  to refer to the shape of an anomalous feature or traumatic lesion caused by a  gunshot wound .


A keyhole defect is characteristic of a type of entrance wound caused by a bullet striking the surface of a flat bone (typically the  cranium ) at a shallow angle. [ 1 ]  The defect is characterized by a rounded portion with a clean margin where the bullet first perforates bone, and a wider area with external beveling on the opposite end.  The keyhole entrance wound can thus indicate the trajectory of the bullet at the time of impact.


In  proctology , a keyhole defect may refer to a groove in the  anal canal  wall, which can occur after posterior midline  fissurectomy  or  fistulotomy  (surgical operations involving the anal canal), or with lateral internal anal sphincter defects. The keyhole defect is associated with minor degrees of  fecal incontinence , allowing seepage of liquid stool or mucus. [ 2 ]


LIFT technique  is the novel modified approach through the  intersphincteric  plane for the treatment of  fistula-in-ano , known as LIFT (ligation of intersphincteric fistula tract) procedure. LIFT procedure is based on secure closure of the internal opening and removal of infected  cryptoglandular  tissue through the intersphincteric approach. Essential steps of the procedure include, incision at the intersphincteric groove, identification of the intersphincteric tract, ligation of intersphincteric tract close to the internal opening and removal of intersphincteric tract, scraping out all  granulation tissue  in the rest of the fistulous tract, and suturing of the defect at the external sphincter muscle. [ 1 ]
The procedure was developed by Thai colorectal surgeon, Arun Rojanasakul, Colorectal Division Department of Surgery,  Chulalongkorn University  in  Bangkok, Thailand . The first report of preliminary healing result from the procedure were 94% in 2007  [ 2 ]


In 1993 Matos et al. described a technique of total anal sphincter preservation in high fistula in ano, which is based on the concept of excision of intersphincteric anal gland infection through the intersphincteric approach. [ 3 ]  This novel technique was also documented in Corman’s textbook of colon and rectal surgery. [ 4 ]  However, the technique was not widely adopted. [ 5 ]
Between 2004 and 2005 there was a personal experience in the similar technique by group of surgeons. That technique included coring out the intersphinteric fistula tract from the external opening to the external sphincter, excision of the intersphincteric fistula tract and suture of the internal sphincter defect through the intersphincteric plane. The outcome in 20 patients was disappointing with only 9 (45%) successes. Surgeons proposed that the reasons for the unfavorable outcome include dissection in the intersphincteric plane damaging blood supply to the internal opening area, and suturing delicate ischemic areas with increased risk of suture break-down. Surgeons thought that ligation of the intersphincteric tract close to the internal opening might solve the problem. Surgeons noticed that during intersphincteric plane dissection if the internal sphincter was damaged and the anal mucosa breached, failure was common despite meticulous repair. [ 2 ]


Researchers of the procedure agree that the LIFT technique may cause some injury to internal sphincter, but theoretically LIFT causes less trauma of the internal sphincter than the other fistula operations.  Matos et al. reported the technique of excision of the whole fistula tract plus primary repair, with intersphincteric plane approach for excision of the fistula tract and suturing of the internal anal sphincter defect, in 1993. [ 3 ]  However, Rojanasakul reported the ligation of intersphincteric fistula tract in 2007 with apparent satisfactory results probably due to secured closure of the internal opening. [ 2 ]  This represents a significant change from the originally described technique with improved outcomes . [ 6 ]


Low anterior resection syndrome  is a  complication  of  lower anterior resection , a type of surgery performed to remove the  rectum , typically for  rectal cancer . It is characterized by changes to bowel function that affect quality of life, and includes symptoms such as  fecal incontinence , incomplete defecation or the sensation of incomplete defecation ( rectal tenesmus ), changes in stool frequency or consistency, unpredictable bowel function, and painful defecation ( dyschezia ). [ 1 ]  Treatment options include symptom management, such as use of  enemas , or surgical management, such as creation of a  colostomy . [ 2 ]


Low anterior resection syndrome falls into two groups. Fecal urgency,  incontinence , and increased frequency make up the first.  Constipation , a sense of incomplete evacuation, and trouble emptying the bowels are included in the second category. Some patients describe characteristics from both groups, either switching back and forth between the two patterns or going through both at once. [ 3 ]


Low anterior resection syndrome emerges after rectal resection. [ 4 ]


The two factors that negatively affect patients' bowel function after lower anterior resection are low tumor height and  radiation , either pre- or post-operative. Additionally linked to worse bowel function are  stomas  that are temporary in nature and those that have been in place for an extended length of time. This, however, is probably a reflection of the height of the tumor and potential surgical complications, which may also have a deleterious effect on bowel function. [ 5 ]


Multiple factors likely contribute to low anterior resection syndrome. During intersphincteric resection, the  internal anal sphincter  may sustain direct structural damage that leads to fecal  incontinence , or secondary damage from the insertion of an anastomotic device through the  anus  during low anterior resection. [ 6 ]  In particular, if the surgical approach reaches the posterolateral side of the  prostate  (in men), where both the  sympathetic  and  parasympathetic   nerve fibers  enter the rectal wall, damage to the  internal anal sphincter 's nerve supply may also result in dysfunction. [ 7 ] [ 8 ]


When performing a low anterior resection, the conjoint longitudinal muscle may also sustain damage during the surgical dissection of the intersphincteric space. [ 3 ]  Furthermore, in order to achieve a sufficient horizontal marginanally, the  rectococcygeus muscle  is frequently divided, which impairs the muscle's functionality. [ 7 ]


A decrease in the maximum allowable rectal volume following low anterior resection and an increase in the false urge to urinate can result from poor compliance brought on by rectal volume loss. [ 9 ]


The extrinsic  spinal cord  nerves that mediate the rectoanal inhibitory reflex may also be injured during a low anterior resection, resulting in intestinal dysfunction. [ 10 ] [ 11 ]


Low anterior resection syndrome can be assessed using two patient questionnaires that have been validated. [ 3 ]  After sphincter-preserving surgery, the 18-item validated  Memorial Sloan Kettering Cancer Center  Bowel Function Instrument (MSKCC-BFI) can be used to assess bowel function. It was developed in 2004. [ 12 ]  A 5-item validated questionnaire called the LARS score was developed in 2012 by Emmertsen et al. in a Danish population as a second scoring system to evaluate bowel function following sphincter-preserving surgery for rectal cancer. [ 13 ]


Anorectal manometry  objectively assesses anal sphincter function and rectal capacity by recording resting pressure, maximum squeezing pressure, rectoanal inhibitory reflex, rectal capacity, and compliance with a balloon catheter and pressure sensor. Although it can be used to direct and track the effectiveness of therapy,  anorectal manometry  is not necessary for the diagnosis of low anterior resection syndrome. [ 14 ]


Endoscopic rectal ultrasound  is a useful tool for evaluating the  pelvic floor  and sphincter complex structure. [ 15 ]


Fecoflowmetry is a valuable technique for evaluating anorectal motor function following surgery. It works by tracking changes in flow against time and analyzing the fecal flow rate, which is the result of rectal detrusor action against anorectal outlet resistance. [ 16 ]


The foundation of treatment for low anterior resection syndrome is conservative therapy, including pelvic floor rehabilitation,  colonic irrigation , or minimally invasive procedures, such as spinal nerve stimulation. [ 17 ]


For the short-term treatment of a single symptom, certain patients should be treated with loperamide or  antibiotics  like neomicine or  rifaximin  (in the event of proximal expansion of native gut microbes or  small-intestinal bacterial overgrowth  shown with the  lactulose  breath test). [ 17 ]


Although  bile acid sequestrants  like  colesevelam  and  5-HT3 antagonists  like  ramosetron  have shown intriguing early results, more research is still needed. [ 17 ]


Transanal irrigation is an inexpensive and successful treatment for the high frequency of defecations and incontinence linked to low anterior resection syndrome. [ 18 ] [ 19 ]


Sacral nerve stimulation  (SNS) is associated with improved fecal incontinence and deferred defecation among individuals with normal as well as impaired sphincters, as well as in patients with low anterior resection syndrome. [ 20 ]


When  fecal incontinence  becomes unmanageable, surgery may be a viable treatment option. When all other forms of treatment have been exhausted, a  stoma  should be taken into consideration. Sphincteric substitution and other advanced surgical techniques ought to be reserved for a very select group of patients. [ 17 ]


These procedures aim to inject  bio-compatible  material ( perianal injectable bulking agents , also termed  sphincter bulking agents [ 1 ]  or  biomaterial injectables ) [ 2 ]  into the walls of the anal canal, in order to bulk out these tissues. This may bring the walls of the anal canal into tighter contact, raising the resting pressure, creating more of a barrier to the loss of stool, and thereby reducing  fecal incontinence . This procedure has many advantages over more invasive surgery, since there are rarely any serious complications. [ 3 ]


Originally, injectable bulking agents were used to treat  stress urinary incontinence  in females. [ 4 ]  The procedure aimed to bulk out the tissues of the neck of the bladder, and it was successful. [ 5 ]  The technique was first used for FI in 1993 by an Egyptian surgeon. [ 6 ]  He used  polytetrafluroethylene  (PTFE/polytef/Teflon) paste injected into the submucosal layer of anal canal. [ 5 ] [ 4 ]  Later publications described autologous transplantation of fat from the abdominal wall or the buttock. [ 5 ] [ 4 ]  After about the year 2000, many different materials started to be used as well as variations of the technique. Some of these materials were concurrently being used to treat urinary incontinence. The latest development of this technique is the  implantable bulking agents  "Gatekeeper" and "Sphinkeeper". [ 4 ]  These are not injectable materials but rather implants which expand after placement. [ 7 ]  As such, they are termed "self-expandable prostheses", and the term "non-self-expandable prostheses" is used to refer to older injectable materials. [ 7 ]


The exact methods of this procedure are not standardized and vary considerably, [ 8 ] [ 9 ]  for example the exact number and locations of the injections and the volume of the injected material. [ 3 ]


Before the operation, antibiotic prophylaxis may be given. [ 10 ]  The rectum is prepared with a phosphate enema at least 2 hours before the procedure. [ 10 ]  The procedure can be carried out under  local anesthetic  on an  out patient  basis, or with  caudal epidural anesthesia , [ 8 ]  or with  intravenous sedation , or under  general anesthesia . [ 3 ]   Ultrasound  guidance may be used during the injections, which is sometimes reported as being more effective than the surgeon simply  palpating  (feeling) and looking where to inject.


The site of the bulking material can be inter-sphincteric (in the space between the IAS and the EAS), submucosal injections (under the mucosal layer, usually just above the dentate line), or within the IAS itself. [ 3 ] [ 4 ]  Injection of the material can be by the different routes: transanal route, trans-sphincteric, intersphincteric, perianal route (going through the muscle complex) or transcutaneous route. [ 3 ]  As such, there are several different variations of injection location and route: [ 10 ]


The perianal injection route (intersphincteric or transsphincteric) gives better results than the transanal route according to one review. [ 3 ]  Submucosal implant location may have a higher risk of erosion and sepsis. [ 10 ]


Many different materials have been used as perianal injectable bulking agents. [ 11 ]  The ideal injectable or implantable material would be biocompatible, non-migratory, non- allergenic , non- carcinogenic  and non-immunogenic (and therefore induce a minimal inflammatory and fibrotic reaction). [ 5 ] [ 4 ] [ 10 ]  The material should also be easy to inject. The particles should be greater than 80 μm in diameter in order to prevent migration away from the injection site. On the other hand, materials with particles small enough to be used in small caliber needles may be desirable, in order to leave a smaller needle track, which may reduce the chance of leakage of the material via the needle track. Alternatively, some materials are shape-retaining porous hydrogels with no particles. [ 5 ]  The ideal material should produce an improvement in continence not only in the short term, but in the long term, and repeated procedures should not be necessary. [ 4 ]  Technically, most materials are particles suspended in a carrier (excipient) solution, which is usually a biodegradable gel. [ 12 ] [ 10 ]  It is not known which of the available materials is the best. [ 8 ]


This was the original material used as a bulking agent, first used to treat urinary incontinence in 1964, and then about 20 years later it was the first material used as a bulking agent to treat FI.  Polytef paste is  polytetrafluoroethylene ,  glycerin  and  polysorbide . The particles are mostly very small in size (4–40-μm). Research in animals has shown that these particles migrate and may be found in lymph nodes, lungs, kidneys, spleen and brain. [ 5 ]  If the material mostly migrates away, any benefit will be temporary, and there are safety concerns that it could lead to the formation of foreign body  granulomas  and the development of  sarcoma . [ 4 ] [ 5 ]


This variation of the procedure uses the patient's own fat cells, and therefore is non-allergenic and non-immunogenic. [ 5 ]  The fat cells are taken from the abdominal wall by suction. Then they are purified and put into a saline solution before injection. [ 10 ]  When used in other fields such as urology or facial surgery, autologous fat transplants have very rarely been reported to cause  fat embolism  and  stroke . [ 4 ]  This material is also subject to rapid digestion and migration. [ 10 ]


This is a silicone biomaterial, marketed as "PTQ" or "Bioplastique". It is polydimethylsiloxane elastomer particles suspended in a biocompatible carrier hydrogel of  poly-N-vinyl-pyrrolidone  (povidone). Significantly more publications exist which investigate this material compared to the other materials, [ 4 ]  and it has been the most widely used bulking material used for FI. [ 10 ]  Publications used inter-sphincteric or  within IAS injection sites via the trans-sphincteric route. [ 4 ]  The particles are in the range 100–450 μm with smaller particles in the gel. Therefore there is a possibility of migration and granuloma formation. There are also concerns about a link between autoimmune diseases and silicone. The bulking agent is very viscous which makes it difficult to inject. [ 5 ]  After injection there is irregular collagen deposition around and inside the implant. [ 10 ]


After PTQ, this material has most scientific publications. Publications described using it via the transmucosal or trans-sphincteric routes, with the end location of the material being the submucosa. It is composed of carbon-coated zirconium beads (pyrolytic carbon-coated beads) in a water-based carrier gel containing  β-glucan . [ 4 ]  Pyrolytic carbon is not biologically reactive and does not undergo degradation. It is used in various medical devices including heart valves. The particle size of Durasphere is in the range 212-500 μm, [ 5 ]  which is approximately 3 times the migration threshold of 80 μm. [ 10 ]  However, one report of the material as used in urology showed significant migration to local and distant lymph nodes. [ 5 ]


This is a newer material which became more popular after 2011. [ 2 ]  It is marketed as NASHA Dx, Zuidex, or Solesta. [ 4 ]  As of 2022, NASHA Dx is the only material approved in the US by the U.S. Food and Drug Administration (FDA). [ 8 ]  This material is composed of crosslinked dextranomer (dextran) microspheres and non-animal stabilized sodium hyaluronate (NASHA) in phosphate-buffered 0.9%  sodium chloride  solution. [ 4 ]  The particles are 120 μm in diameter. The material is non-allergenic, non-immunogenic and non-migratory. After injection, the hyaluronic acid is degraded, and soft tissue fibrosis forms with ingrowth of fibroblasts, inflammatory cells, blood vessels and collagen. This means that even though the particles undergo degradation, the bulking effects may persist. [ 5 ]  There are several publications which report the use of this material. They used submucosal injection site via the transmucosal route. [ 4 ]  Uncertainty about indications, cost, and durability of the material in the long term stopped widespread adoption of this material. [ 2 ]


Marketed as "Coaptite", this is spherical particles of calcium hydroxylapatite ceramic suspended in a sodium carboxylmethylcellulose, glycerine and water carrier gel. [ 4 ]  This is a synthetic version of a compound that is a normal component of bones and teeth. It is non-antigenic and noninflammatory. The particle size is in the range 75–125 μm and therefore should avoid migration away from the implant site.  Once in place, the particles are enmeshed in a non-encapsulated stable soft collagen matrix. This matrix maintains volume even after the solid particles have been degraded and resorbed. The material is radio-opaque (and therefore will be visible on x-rays). It has been used in dental and orthopedic reconstructive surgery, and for replacement heart valves. In the field of plastic surgery, it is termed Radiance FNTM. [ 5 ]  As of 2022 only one publication exists. The material was used in submucosal injection site via transsphincteric route. [ 4 ]


GAX (glutaraldehyde cross-linked) collagen is purified collagen from cow skin, marketed as Contigen. [ 5 ] [ 4 ]  Enzymes are used to remove  telopeptides , which reduces the antigenicity (the degree to which the body's immune cells will be able to recognize the material as a foreign body). About 5% of patients will have an immune reaction to this material, therefore allergy testing is carried out before the final procedure. There is also a concern about disease transmission. [ 5 ]  This material contains 95% collagen Type I and 1-5% of collagen Type III. [ 10 ]  Chemical cross-linking with glutaraldehyde is intended to stop the degradation of the material by collagenases. [ 5 ]  The carrier solution is physiological saline with phosphate. [ 10 ]  The material does not seem to be associated with formation of granulomas or migration, however it is subject to degradation over time. [ 5 ]  In publications is has been used with submucosal injection site via transmucosal route. [ 4 ]  This material has not achieved widespread use. [ 12 ]


Cross-linked porcine dermal collagen matrix (collagen from pig skin) has been used, marketed as Permacol. [ 5 ]  It consists of large particles of cross-linked porcine dermal collagen. [ 10 ]  It has been used for urinary incontinence and for facial contour augmentation, as well as for FI. It is biocompatible, non-allergenic and has improved durability due to revascularization and cell ingrowth following injection. [ 5 ]  In several publications where the material was used for FI, submucosal or intersphincteric injection site was used, via the transmucosal or intersphincteric routes. [ 4 ]


Marketed as Bulkamid, this material is a synthetic non-particulate hydrogel composed of water and cross-linked polyacrylamide (2.5%). [ 4 ]  The size of the molecules is large which makes it resistant to migration. Since it is a non particulate homogeneous hydrogel, it is thought to retain elasticity and does not lead to hard tissue fibrosis or cause other significant reaction in the surrounding tissues. [ 5 ] [ 10 ]  It is non-resorbable and non allergenic. In plastic surgery it is marketed as Aquamid. [ 5 ]  In one publication where it was used for FI, intersphincteric injection site was used via the intersphincteric route. [ 4 ]  This material has not achieved widespread use. [ 12 ]


ALTA injection is somewhat different to the other materials because it is a sclerosant (i.e. it is a type causes  sclerosis , or hardening of tissue). Therefore, it may be technically classified as a type of  sclerotherapy . This injectable material has been used for treatment of grade III to IV prolapsed internal  hemorrhoids , where it gives effects similar to  hemorrhoidectomy . It has also been used for treatment of  rectal prolapse  and  rectocele . [ 8 ]  The material causes a local inflammatory reaction, followed by sclerosis and retraction of tissues. This results in a chronic granulomatous inflammatory process and persistent  fibrosis . When used to treat rectal prolapse or mucosal prolapse, it is injected into a wider area (not just into the hemorrhoid cushions, but also into parts of the rectal mucosa), leading to thickening and toughening of the anal canal and rectal wall. This has been shown to increase the maximal resting pressure of the anal canal. Therefore, the result is thought to be similar to other injectable bulking agents, although it is claimed that there is no risk of dissipation and no need for repeated procedures. ALTA has the advantage that it may be used to treat related anorectal conditions which would be contraindications for other injectable bulking agents. [ 8 ]


8% ethylene vinyl alcohol co-polymer in dimethyl sulfoxide solution has been used. For FI it is marketed as Onyx34, and for gastroesophageal reflux disease it is marketed as Enteryx. [ 5 ] [ 4 ]  After injection, it forms a spongy solid mass via solidification of the hydrophobic copolymer. This occurs because the co-polymer is hydrophic, and the solvent is dissolved away upon contact with tissues. In one publication inter-sphincteric injection site was used via the inter-sphincteric route. [ 4 ]


Mesenchymal stem cells  (MSC) and  muscle-derived stem cells  (MDSC) have been used in urology to treat urinary incontinence.  Fibroblasts  in a collagen carrier were injected into the submucosa of the urethra, and  myoblasts  were injected into the urethral sphincter. The procedure was reported as being successful in most cases. [ 5 ]  Injection of MSCs may lead to engrafting and forming multinucleated myotubes, which helps to regeneration after injury. [ 10 ]  In theory, use of stem cells removes the problems of reabsorption and migration of the bulking material. [ 5 ]  There is similar research which aims to regenerate muscles and repair tissues by  cell therapy  to treat injuries of the external anal sphincter. [ 11 ]


The "Gatekeeper" and "Sphinkeeper" are related procedures. They are self-expandable prostheses which are implanted into the inter-sphincteric space of the anal canal using an applicator gun. [ 8 ] [ 2 ]  Gatekeeper is a solid  polyacrylonitrile  (hyexpan) cylinder which expands to approximately 720% original size within 24 hours after the implantation. [ 10 ] [ 2 ]


One review of 23 publications involved a total of 889 patients reported an overall rate of complications of 18%. [ 3 ]


Reported complications are mostly minor, and include: bleeding, perianal pain / discomfort (which may rarely be persistent), leakage of injected material, infection / abscess (which rarely may require drainage), mucosal erosion,  obstructed defecation , hypersensitivity reaction, hematoma, diarrhea,  pruritus ani ,  dermatitis , and bowel urgency (sudden strong urge to defecate). [ 3 ] [ 9 ]


A landmark randomized placebo control trial on NASHA Dx was published in 2011 in the Lancet. [ 13 ]  136 were given real injections and 70
patients were given shame (fake) injections. 80% of the patients had no improvement 1 month after the procedure, and were given a second injection. [ 14 ]  After 6 months, 52% of patients who received real injections had improved symptoms. [ 15 ]  However, the patients who received fake injections reported over 30% improvement in symptoms, suggesting that patient psychology (i.e. the  placebo effect ) may be in part responsible for any positive results. [ 16 ]  6% of patients who received real injections were fully continent after 6 months. [ 14 ]  After publication of this study, the material was approved by the FDA in the USA in 2012. [ 14 ]  The material was aggressively marketed, and became popular for a time because of its potential as an in office treatment with low risks compared to other surgical options. [ 2 ]  However uncertainty about indications, cost, and long term durability stopped widespread adoption. [ 2 ]


A  Cochrane  systematic review of the efficacy of this type of treatment for FI was updated in 2013. The review included 5 randomized trials, which in total was 382 patients. 4 of the trials were assessed as uncertain or high risk of bias. [ 11 ]  Another commentator drew attention to the fact that all existing research on these procedures was driven by the companies who also marketed the treatments, and therefore the studies are indeed at high risk of bias. [ 16 ]  Another author in 2008 raised concern that 2 randomized placebo controlled trials had been conducted, but their results remained unpublished for unknown reasons. [ 9 ]  None of the studies in the Cochrane review reported long term follow up after 3, 6 or 12 months post procedure. Another problem with some of the trials is that they were too small. [ 11 ]


The Cochrane review found that most trials reported short term improvement following the procedure, regardless of which material was used. In some studies in the control groups, even placebo (sham) injections and saline injections lead to patients reporting improvement. One trial showed that dextranomer (NASHA Dx) was more effective six months after the procedure compared to placebo for just over half of patients. Another study showed that PTQ has some advantages and was safer than Durasphere in the short term. The authors concluded that due to the small amount of research available and its methodological weaknesses, further conclusions could not be made, especially regarding the long term effectiveness of the procedure. [ 11 ]


Another review which aimed to focus on the long term impact of the procedure included 889 patients across 23 studies. It reported a pooled improvement rate in measures of incontinence of 39.5%, on average 2 years after the procedure. [ 3 ]  In some cases there was no improvement after the procedure, and the injections needed to be repeated in up to 34% of cases. [ 3 ]  There can also be worsening of symptoms after an initial improvement period. [ 3 ]


A randomized trial by Dehli  et al . compared perianal injectable bulking agents to sphincter training and biofeedback, and found the former to be superior. Both methods lead to an improvement of FI, but comparisons of  St Mark's scores  between the groups showed no difference between treatments. [ 17 ]


Anal manometry  is sometimes used to investigate changes in the anal canal before and after the procedure. Usually mean anal resting pressure and mean anal squeeze pressure are the parameters used. [ 3 ]  Improvements in these measurements are often, but not always reported up to 3–12 months after the procedure. These improvements are not always maintained after 12 months. [ 3 ]  The length of the anal canal has also been reported to increase following the procedure. [ 3 ]  In one report, dextranomer did not increase anal resting or squeeze pressures. [ 15 ]  In the same study, dextranomer injections were found to be no different to  biofeedback . [ 15 ]


There is limited research available on this topic, and these publications are mostly of poor quality. [ 11 ]  Apart from the available research, most of the claims of benefit of these procedures is anecdotal. [ 11 ]


One author criticized these procedures, stating that simply narrowing the anal canal was an instinctive and naïve solution which does not consider the complex pathopysiological mechanisms of FI. [ 16 ]  They suggested that these treatments are in theory suitable only for passive and minor forms of FI. [ 16 ]  Concerns have been raised about migration of the particles (in the case of Durasphere) away from the site of injection, or the total resorption of the material (in the case of hyaluronic acid and hydroxyl coaptite). [ 16 ]  Most research suggests that the positive effects of most of the bulking agents seem to reduce after 6 to 12 months. [ 8 ]  Endoanal ultrasound has sometimes been used to assess the presence of the material at follow up. At 6 months the material has been reported as missing or migrated in 18.4% of cases, at 3 years or more in 20.2% of cases. [ 3 ]  NASHA Dx and ALTA injection may have longer lasting effects, with most patients still having improvement after 3 years. [ 8 ]


The  pinworm  ( species   Enterobius vermicularis ), also known as  threadworm  (in the United Kingdom, Australia and New Zealand) or  seatworm , is a  parasitic worm .  It is a  nematode  (roundworm) and a common  intestinal parasite  or  helminth , especially in humans. [ 7 ]  The medical condition associated with pinworm infestation is known as  pinworm infection  ( enterobiasis ) [ 8 ]  (a type of  helminthiasis ) or less precisely as oxyuriasis in reference to the  family   Oxyuridae . [ 9 ]


Other than human,  Enterobius vermicularis  were reported from  bonnet macaque . [ 10 ]  Other species seen in  primates  include  Enterobius buckleyi  in  Orangutan [ 11 ]  and  Enterobius anthropopitheci  in  chimpanzee .   Enterobius vermicularis  is common in human children and transmitted via the faecal-oral route. Humans are the only natural host of   Enterobius vermicularis . [ 12 ]   Enterobius gregorii , another human species is morphologically indistinguishable from  Enterobius vermicularis  except the  spicule  size. [ 13 ]  Throughout this article, the word "pinworm" refers to  Enterobius . In British usage, however, pinworm refers to  Strongyloides , while  Enterobius  is called threadworm. [ 14 ]


The pinworm (genus  Enterobius ) is a type of  roundworm  (nematode), and three species of pinworm have been identified with certainty. [ 15 ]  Humans are hosts only to  Enterobius vermicularis  (formerly  Oxyurias vermicularis ). [ 16 ]   Chimpanzees  are host to  Enterobius anthropopitheci , which is  morphologically  distinguishable from the human pinworm. [ 5 ]  Hugot (1983) claims another species affects humans,  Enterobius gregorii , which is supposedly a  sister species  of  E. vermicularis , and has a slightly smaller  spicule  (i.e., sexual organ). [ 17 ]  Its existence is controversial, however; Totkova et al. (2003) consider the evidence to be insufficient, [ 6 ]  and Hasegawa et al. (2006) contend that  E. gregorii  is a younger stage of  E. vermicularis . [ 4 ] [ 5 ]  Regardless of its status as a distinct species,  E. gregorii  is considered clinically identical to  E. vermicularis . [ 16 ]


The adult female has a sharply pointed  posterior  end, is 8 to 13 mm long, and 0.5 mm thick. [ 18 ]  The adult male is considerably smaller, measuring 2 to 5 mm long and 0.2 mm thick, and has a curved posterior end. [ 18 ]  The eggs are  translucent [ 18 ]  and have a surface that adheres to objects. [ 19 ]  The eggs measure 50 to 60  μm  by 20 to 30 μm, and have a thick shell flattened on one side. [ 18 ]  The small size and colourlessness of the eggs make them invisible to the naked eye, except in barely visible clumps of thousands of eggs. Eggs may contain a developing  embryo  or a fully developed pinworm  larva . [ 18 ]  The larvae grow to 140–150 μm in length. [ 19 ]


The entire life cycle, from egg to adult, takes place in the  human gastrointestinal tract  of a single host, [ 18 ] [ 19 ]  from about 2–4 weeks [ 20 ]  or about 4–8 weeks. [ 21 ]   E. vermicularis  molts four times; the first two within the egg before hatching and two before becoming an adult worm. [ 22 ]


Although infection often occurs via  ingestion  of embryonated eggs by inadequate hand washing or nail biting, inhalation followed by swallowing of airborne eggs may occur rarely. [ 19 ] [ 21 ]  The eggs hatch in the  duodenum  (i.e., first part of the  small intestine ). [ 23 ]  The emerging pinworm  larvae  grow rapidly to a size of 140 to 150 μm, [ 20 ]  and migrate through the small intestine towards the  colon . [ 19 ]  During this migration, they  moult  twice and become adults. [ 19 ] [ 21 ]  Females survive for 5 to 13 weeks, and males about 7 weeks. [ 19 ]  The male and female pinworms mate in the  ileum  (i.e., last part of the small intestine), [ 19 ]  whereafter the male pinworms usually die, [ 23 ]  and are passed out with stool. [ 24 ]  The gravid female pinworms settle in the  ileum ,  caecum  (i.e., beginning of the  large intestine ),  appendix  and  ascending colon , [ 19 ]  where they attach themselves to the  mucosa [ 21 ]  and ingest colonic contents. [ 25 ]


Almost the entire body of a  gravid  female becomes filled with eggs. [ 23 ]  The estimations of the number of eggs in a gravid female pinworm range from about 11,000 [ 19 ]  to 16,000. [ 21 ]  The egg-laying process begins about five weeks after initial ingestion of pinworm eggs by the human host. [ 19 ]  The gravid female pinworms migrate through the colon towards the  rectum  at a rate of 12 to 14 cm per hour. [ 19 ]  They emerge from the  anus , and while moving on the skin near the anus, the female pinworms deposit eggs either through (1) contracting and expelling the eggs, (2) dying and then disintegrating, or (3) bodily rupture due to the host scratching the worm. [ 23 ]  After depositing the eggs, the female becomes  opaque  and dies. [ 24 ]  The female emerges from the anus to obtain the oxygen necessary for the maturation of the eggs. [ 24 ]


E. vermicularis  causes the medical condition  pinworm infection  also known as  enterobiasis , whose primary symptom is  itching  in the anal area. [ 26 ]  Extraintestinal disease is rare and most commonly involves the female reproductive tract, [ 27 ]  but spleen abscess has also been reported. [ 28 ]  Enterobius vermicularis infections are found to be correlated with stunting and lower mean  I.Q.  among prepubescent children. [ 29 ] [ 30 ]


The pinworm has a worldwide distribution, [ 25 ]  and is the cause of the most common  helminthiasis  ( parasitic worm  infection) in the United States, western Europe, and Oceania. [ 21 ]  In the United States, a study by the  Center of Disease Control  reported an overall  incidence rate  of 11.4% among children. [ 21 ]  Pinworms are particularly common in children, with  prevalence rates  in this age group having been reported as high as 61% in India, 50% in England, 39% in Thailand, 37% in Sweden, and 29% in Denmark. [ 21 ]   Finger sucking  has been shown to increase both incidence and relapse rates, [ 21 ]  and  nail biting  has been similarly associated. [ 31 ]  Because it spreads from host to host through  contamination , pinworms are common among people living in close contact, and tends to occur in all people within a household. [ 25 ]  The prevalence of pinworms is not associated with gender, [ 25 ]  nor with any particular social class,  race , or culture. [ 21 ]  Pinworms are an exception to the tenet that intestinal parasites are uncommon in affluent communities. [ 21 ]


A fossilized nematode egg was detected in 240 million-year-old fossil dung, [ 32 ]  showing that parasitic pinworms already infested pre-mammalian  cynodonts . The earliest known instance of the pinworms associated with humans is evidenced by pinworm eggs found in human  coprolites   carbon dated  to 7837 BC found in western  Utah . [ 19 ]


Pinworm infection  ( threadworm infection  in the UK), also known as  enterobiasis , is a  human parasitic disease  caused by the  pinworm ,  Enterobius vermicularis . [ 3 ]  The most common symptom is  pruritus ani , or  itching  in the  anal  area. [ 1 ]   The period of time from swallowing eggs to the appearance of new eggs around the anus is 4 to 8 weeks. [ 2 ]  Some people who are infected do not have symptoms. [ 1 ]


The disease is spread between people by pinworm eggs. [ 1 ]  The eggs initially occur around the anus and can survive for up to three weeks in the environment. [ 1 ]  They may be swallowed following contamination of the hands, food, or other articles. [ 1 ]  Those at risk are those who go to school, live in a health care institution or prison, or take care of people who are infected. [ 1 ]  Other animals do not spread the disease. [ 1 ]  Diagnosis is by seeing the worms which are about one  centimetre  long or the eggs under a  microscope . [ 1 ] [ 6 ]


Treatment is typically with two doses of the medications  mebendazole ,  pyrantel pamoate , or  albendazole  two weeks apart. [ 4 ]  Everyone who lives with or takes care of an infected person should be treated at the same time. [ 1 ]  Washing personal items in hot water after each dose of medication is recommended. [ 1 ]  Good  handwashing , daily bathing in the morning, and daily changing of  underwear  can help prevent reinfection. [ 1 ]


Pinworm infections commonly occur in all parts of the world. [ 1 ] [ 5 ]  They are the most common type of worm infection in  Western Europe ,  Northern Europe  and the  United States . [ 5 ]  School-aged children are the most commonly infected. [ 1 ]  In the United States about 20% of children will develop pinworm at some point. [ 3 ]  Infection rates among high-risk groups may be as high as 50%. [ 2 ]  It is not considered a serious disease. [ 5 ]  Pinworms are believed to have affected humans throughout history. [ 7 ]


One-third of individuals with pinworm infection are totally  asymptomatic . [ 8 ]  The main symptoms are  itching in and around the anus  and  perineum . [ 8 ] [ 9 ] [ 10 ]  The itching occurs mainly during the night, [ 9 ] [ 11 ]  and is caused by the female pinworms migrating to lay eggs around the anus. [ 12 ] [ 10 ]  Both the migrating females and the clumps of eggs are irritating, as well as the sticky substance that is produced by the worms when the eggs are laid. [ 11 ] [ 13 ]  The intensity of the itching varies, and it can be described as  tickling , crawling sensations, or even acute  pain . [ 14 ]  The itching leads to continuously scratching the area around the anus, which can further result in tearing of the skin and complications such as  secondary bacterial infections , including  bacterial   skin inflammation , and  hair follicle inflammation . [ 9 ] [ 10 ] [ 14 ]  General symptoms are  trouble sleeping , and  restlessness . [ 9 ]  A considerable proportion of children experience loss of appetite,  weight loss ,  irritability , emotional instability, and  bed wetting . [ 9 ]


Pinworms cannot damage the skin, [ 15 ]  and they do not normally migrate through  tissues . [ 10 ]  However, they may move onto the  vulva  and into the  vagina , from there moving to the  external orifice of the uterus , and onwards to the  uterine cavity ,  fallopian tubes ,  ovaries , and  peritoneal cavity . [ 15 ]  This can cause  inflammation of the vulva and vagina . [ 9 ] [ 10 ]  This causes  vaginal discharge  and  itchiness of the vulva . [ 9 ]  The pinworms can also enter the  urethra , and presumably, they carry intestinal bacteria with them. [ 15 ]  According to Gutierrez (2000), a statistically significant correlation between pinworm infection and  urinary tract infections  has been shown; [ 15 ]  however, Burkhart & Burkhart (2005) maintain that the incidence of pinworms as a cause of urinary tract infections remains unknown. [ 8 ]  One report indicated that 36% of young girls with a  urinary tract infection  also had pinworms. [ 8 ]   Painful urination  has been associated with pinworm infection. Sometimes, pinworms can be stopped before reaching the vaginal area  [ 8 ]


The relationship between pinworm infestation and  appendicitis  (a condition in which the appendix becomes inflamed and filled with pus, causing pain) has been researched, but there is a lack of clear consensus on the matter: While Gutiérrez maintains that there exists a consensus that pinworms do not produce the inflammatory reaction, [ 16 ]  Cook (1994) states that it is controversial whether pinworms are causatively related to acute  appendicitis , [ 14 ]  and Burkhart & Burkhart (2004) state that pinworm infection causes symptoms of appendicitis to surface. [ 8 ]


The cause of a pinworm infection is the worm  Enterobius vermicularis .  The entire lifecycle – from egg to adult – takes place in the  human gastrointestinal tract  of a single human host. [ 12 ] [ 17 ]  This process is two to eight weeks. [ 18 ] [ 9 ]


Pinworm infection spreads through human-to-human  transmission , by swallowing infectious pinworm eggs. [ 18 ] [ 19 ]  The eggs are hardy and can remain infectious in a moist environment for up to three weeks, [ 11 ] [ 18 ]  though in a warm dry environment they usually last only 1–2 days. [ 20 ]  They do not tolerate heat well, but can survive in low temperatures: at −8 degrees Celsius (18 °F), two-thirds of the eggs are still viable after 18 hours. [ 11 ]


After the eggs have been initially deposited near the anus, they are readily transmitted to other surfaces through  contamination . [ 19 ]  The surface of the eggs is sticky when laid, [ 12 ] [ 11 ]  and the eggs are readily transmitted from their initial deposit near the anus to fingernails, hands, night-clothing and bed linen. [ 9 ]  From here, eggs are further transmitted to food, water, furniture, toys, bathroom  fixtures  and other objects. [ 12 ] [ 18 ] [ 19 ]  Household pets often carry the eggs in their fur, while not actually being infected. [ 21 ]  Dust containing eggs can become airborne and widely dispersed when dislodged from surfaces, for instance when shaking out bed clothes and linen. [ 11 ] [ 18 ] [ 21 ]  Consequently, the eggs can enter the mouth and nose through inhalation, and be swallowed later. [ 9 ] [ 11 ] [ 18 ] [ 19 ]  Although pinworms do not strictly multiply inside the body of their human host, [ 9 ]  some of the pinworm larvae may hatch on the anal  mucosa , and migrate up the  bowel  and back into the  gastrointestinal tract  of the original host. [ 9 ] [ 18 ]  This process is called  retroinfection . [ 11 ] [ 18 ]  According to Burkhart (2005), when this retroinfection occurs, it leads to a heavy  parasitic  load and ensures that the pinworm infestation continues. [ 18 ]  This statement is contradictory to a statement by Caldwell, who contends that retroinfection is rare and not clinically significant. [ 11 ]  Despite the limited, 13-week lifespan of individual pinworms, [ 12 ]   autoinfection  (infection from the original host to itself), either through the anus-to-mouth route or through retroinfection, causes the pinworms to inhabit the same host indefinitely. [ 18 ]


The life cycle begins with eggs being  ingested . [ 12 ]  The eggs hatch in the  duodenum  (first part of the  small intestine ). [ 19 ]  The emerging pinworm  larvae  grow rapidly to a size of 140 to 150 micrometres, [ 9 ]  and migrate through the small intestine towards the  colon . [ 12 ]  During this migration they  moult  twice and become adults. [ 12 ] [ 18 ]  Females survive for 5 to 13 weeks, and males about 7 weeks. [ 12 ]  The male and female pinworms mate in the  ileum  (last part of the small intestine), [ 12 ]  whereafter the male pinworms usually die, [ 19 ]  and are passed out with stool. [ 11 ]  The gravid female pinworms settle in the  ileum ,  caecum  (beginning of the  large intestine ),  appendix  and  ascending colon , [ 12 ]  where they attach themselves to the  mucosa [ 18 ]  and ingest colonic contents. [ 10 ]  Almost the entire body of a gravid female becomes filled with eggs. [ 19 ]  The estimations of the number of eggs in a gravid female pinworm ranges from about 11,000 [ 12 ]  to 16,000. [ 18 ]  The egg-laying process begins approximately five weeks after initial ingestion of pinworm eggs by the human host. [ 12 ]  The gravid female pinworms migrate through the  colon  towards the  rectum  at a rate of 12 to 14 centimetres per hour. [ 12 ]  They emerge from the  anus , and while moving on the skin near the anus, the female pinworms deposit eggs either through contracting and expelling the eggs, dying and then disintegrating, or bodily rupture due to the host scratching the worm. [ 19 ]  After depositing the eggs, the female becomes opaque and dies. [ 11 ]  The reason the female emerges from the anus is to obtain the oxygen necessary for the maturation of the eggs. [ 11 ]


Diagnosis relies on finding the eggs or the adult pinworms. [ 19 ]  Individual eggs are invisible to the naked eye, but they can be seen using a low-power  microscope . [ 21 ]  On the other hand, the light-yellowish thread-like adult pinworms are clearly visually detectable, usually during the night when they move near the anus, or on toilet paper. [ 8 ] [ 14 ] [ 21 ]  Shining a flashlight on the infected individual's anus about one hour after they fall asleep is one form of detection and may show worms crawling out of the anus. [ 22 ]  Another form of detection is the use of transparent  adhesive tape  (e.g.  Scotch Tape ) applied on the anal area which will pick up deposited eggs, and diagnosis can be made by examining the tape with a microscope. [ 16 ] [ 21 ]  This test is most successful if done every morning for several days, because the females do not lay eggs every day, and the number of eggs varies. [ 21 ]  A third method of diagnosis is examining a sample from under their fingernails under a microscope as itching around the anal area is common and therefore they may have collected some eggs under their nails as a result. [ 23 ]


Pinworms do not lay eggs in the  feces , [ 21 ]  but sometimes eggs are deposited in the intestine. [ 19 ]  As such, routine examination of fecal material gives a positive diagnosis in only 5 to 15% of infected subjects, [ 14 ]  and is therefore of little practical diagnostic use. [ 9 ]  In a heavy infection, female pinworms may adhere to  stools  that pass out through the anus, and they may thus be detected on the surface on the stool. [ 14 ] [ 19 ]  Adult pinworms are occasionally seen during  colonoscopy . [ 14 ]  On a microscopic level, pinworms have an identifying feature of  alae  (i.e., protruding ridges) running the length of the worm. [ 24 ]


Pinworm infection cannot be totally prevented under most circumstances. [ 25 ]  This is due to the prevalence of the parasite and the ease of transmission through soiled night clothes, airborne eggs, contaminated furniture, toys and other objects. [ 19 ]  Infection may occur in the highest strata of society, where hygiene and  nutritional  status are typically high. [ 26 ]  The stigma associated with pinworm infection is hence considered a possible over-emphasis. [ 26 ]   Counselling  is sometimes needed for upset parents who have discovered their children are infected, as they may not realize how prevalent the infection is. [ 19 ]


Preventive action revolves around  personal hygiene  and the cleanliness of the living quarters. [ 26 ]  The  rate  of reinfection can be reduced through hygienic measures, and this is recommended especially in recurring cases. [ 21 ] [ 26 ]


The main measures are keeping fingernails short, and washing and scrubbing hands and fingers carefully, especially after  defecation  and before meals. [ 26 ] [ 27 ]  Showering every morning is also highly recommended to wash off any eggs that may be still lying on the skin. [ 28 ]  Under ideal conditions, bed covers, sleeping garments, and hand towels should be changed daily [ 26 ]  and clothes and linens should be washed in hot water and then be placed in a hot dryer in order to kill off any eggs. [ 28 ]  Children can wear gloves while asleep, and the bedroom floor should be kept clean. [ 26 ]  Regular disinfection of kitchen and bathroom surfaces will help to prevent spread as well. [ 29 ]  Food should be covered to limit contamination with dust-borne parasite eggs. [ 26 ]  It is not recommended to shake clothes and bed linen as the eggs may detach and spread [ 26 ]  or to share clothes and towels. Nail biting and sucking on fingers is also discouraged.


Medication  is the primary treatment for pinworm infection. [ 26 ]  However, reinfection is frequent regardless of the medication used. [ 8 ]  Total elimination of the parasite in a household may require repeated doses of medication for up to a year or more. [ 9 ]  Because the drugs kill the adult pinworms, but not the eggs, the first retreatment is recommended in two weeks. [ 21 ]  Also, if one household member spreads the eggs to another, it will be a matter of two or three weeks before those eggs become adult worms and thus amenable to treatment. [ 27 ]   Asymptomatic  infections, often in small children, can serve as reservoirs of infection, and therefore the entire household should be treated regardless of whether or not symptoms are present. [ 9 ] [ 26 ]


The  benzimidazole  compounds  albendazole  ( brand names  e.g.,  Albenza ,  Eskazole ,  Zentel  and  Andazol ) and  mebendazole  ( brand names  e.g.,  Ovex ,  Vermox ,  Antiox  and  Pripsen ) are the most effective. [ 26 ]  They work by inhibiting the  microtubule  function in the pinworm adults, causing  glycogen  depletion, [ 26 ]  thereby effectively starving the parasite. [ 27 ]  A single 100 milligram dose of  mebendazole  with one repetition after two weeks, is considered the safest, and is usually effective with cure rate of 96%. [ 8 ] [ 26 ]  Mebendazole has no serious  side effects , although  abdominal pain  and  diarrhea  have been reported. [ 26 ]   Pyrantel pamoate  (also called pyrantel embonate,  brand names  e.g.,  Reese's Pinworm Medicine ,  Pin-X ,  Combantrin ,  Anthel ,  Helmintox , and  Helmex ) kills adult pinworms through  neuromuscular blockade , [ 27 ]  and is considered as effective as the  benzimidazole  compounds and is used as a second-line medication. [ 9 ]  Pyrantel pamoate is available over the counter and does not require a prescription. Pinworms located in the  genitourinary system  (in this case, female genital area) may require other drug treatments. [ 8 ]


The available data on mebendazole, albendazole, and pyrantel pamoate use in pregnancy is limited and they are all assigned to  pregnancy category  level C. Treatment of a pinworm infection during pregnancy is only recommended for patients with significant symptoms that may be causing adverse effects to the pregnant woman such as loss of sleep and weight loss. [ 30 ] [ 31 ]  Pyrantel pamoate is the treatment of choice in pregnancy but should be used only after consultation with a health care practitioner rather than self-treatment. [ 30 ]  Treatment should be avoided in the first trimester, and if possible done in the third trimester. [ 32 ] [ 31 ]  If the pregnant woman is asymptomatic, then they should be treated after the baby is delivered. [ citation needed ]


Mebendazole has less than 10% of the oral dose absorbed into systemic circulation with a clinically insignificant amount of drug excreted in breastmilk, and therefore treatment should not be withheld during breastfeeding. [ 31 ]  There is limited data on the use of pyrantel pamoate and albendazole in breastfeeding but  WHO  also classifies them as compatible with breastfeeding. This is due to the drugs acting mainly in the intestinal system of the mother with only a very small amount of drug being absorbed into the systemic circulation. [ 31 ] [ 33 ]


Pinworm infection occurs worldwide, [ 10 ]  and is the most common  helminth  (i.e., parasitic worm) infection in the United States and Western Europe. [ 18 ]  In the United States, a study by the  Center of Disease Control  reported an overall  incidence rate  of 11.4% among people of all ages. [ 18 ]  Pinworms are particularly common in children with approximately 30% of children being infected and most commonly seen in children between 7 and 11 years old. [ 34 ]  The  prevalence rates  in children having been reported as high as 61% in India, 50% in England, 39% in Thailand, 37% in Sweden, and 29% in Denmark. [ 18 ]   Finger sucking  has been shown to increase both incidence and relapse rates, [ 18 ]  and  nail biting  has been similarly associated. [ 14 ]  Because it spreads from host to host through  contamination , enterobiasis is common among people living in close contact, and tends to occur in all people within a household. [ 10 ]  The prevalence of pinworms is not associated with gender, [ 10 ]  nor with any particular  social class ,  race , or culture. [ 18 ]  Pinworms are an exception to the tenet that intestinal parasites are uncommon in affluent communities. [ 18 ]


The earliest known instance of pinworms is evidenced by pinworm eggs found in  coprolite ,  carbon dated  to 7837 BC at western  Utah . [ 12 ]  Pinworm infection is not classified as a  neglected tropical disease  unlike many other parasitic worm infections. [ 35 ]


Garlic  has been used as a treatment in the ancient cultures of China, India, Egypt, and Greece. [ 36 ]   Hippocrates  mentioned garlic as a remedy against intestinal parasites. [ 37 ]  German botanist  Adam Lonicer  also recommended garlic against parasitic worms. [ 38 ]


Proctoscopy , or  rectoscopy , is a common medical procedure in which an instrument called a proctoscope (also known as a  rectoscope , although the latter may be a bit longer) is used to examine the  anal cavity ,  rectum , or  sigmoid colon . A proctoscope is a short, straight, rigid, hollow metal tube, and usually has a small light bulb mounted at the end. It is approximately 15 cm (5 inches) long, while a rectoscope is approximately 25 cm (10 inches) long. [ 1 ]  During proctoscopy, the proctoscope is lubricated and inserted into the  rectum , and then the  obturator  is removed, allowing an unobstructed view of the interior of the rectal cavity. This procedure is normally done to inspect for  hemorrhoids  or rectal  polyps  and might be mildly uncomfortable as the proctoscope is inserted further into the rectum. Modern  fibre-optic  proctoscopes allow more extensive observation with less discomfort.


A  proctoscope  is a hollow, tube-like  speculum  that is used for visual inspection of the rectum. [ 2 ] [ 3 ]  Both disposable and non-disposable proctoscopes are available for use. Out of these, the non-disposable Kelly's rectal speculum, [ 4 ]  named after the American gynecologist  Howard Atwood Kelly , is the most commonly used speculum for proctoscopy. Some proctoscopes have a light source for better visibility. The proctoscope is inserted into the  anal canal  with the patient in  Sims' position . Fibre optic proctoscopes are now available which cause less discomfort to the patient.
The proctoscope is used in the diagnosis of  hemorrhoids , carcinoma of anal canal or rectum and  rectal polyp . It is used therapeutically for  polypectomy  and rectal biopsy.


Disposable proctoscopes without light are also available.   The proctoscope also has a hollow channel through which other instruments may be inserted. For example, another instrument may be used to take a  biopsy  of a small amount of  tissue  for examination under a  microscope . Also, air may be injected through the proctoscope to help make viewing easier. Similar instruments, the  sigmoidoscope  and  colonoscope  may be used to visualize more proximal parts of the bowels.


A  rectal prolapse  occurs when walls of the  rectum  have  prolapsed  to such a degree that they protrude out of the  anus  and are visible outside the body. [ 2 ]  However, most researchers agree that there are 3 to 5 different types of rectal prolapse, depending on whether the prolapsed section is visible externally, and whether the full or only partial thickness of the rectal wall is involved. [ 3 ] [ 4 ]


Rectal prolapse may occur without any symptoms, but depending upon the nature of the prolapse there may be  mucous discharge  (mucus coming from the anus),  rectal bleeding , degrees of  fecal incontinence , and  obstructed defecation  symptoms. [ 5 ]


Rectal prolapse is generally more common in elderly women, although it may occur at any age and in either sex. It is very rarely life-threatening, but the symptoms can be debilitating if left untreated. [ 5 ]  Most external prolapse cases can be treated successfully, often with a surgical procedure. Internal prolapses are traditionally harder to treat and surgery may not be suitable for many patients.


The different kinds of rectal prolapse can be difficult to grasp, as different definitions are used and some recognize some subtypes and others do not. Essentially, rectal prolapses may be: [ citation needed ]


External (complete) rectal prolapse  (rectal procidentia, full thickness rectal prolapse, overt rectal prolapse [ 6 ] ) is
a full thickness, circumferential, true intussusception of the rectal wall which protrudes from the anus and is visible externally. [ 7 ] [ 8 ]


Internal rectal intussusception  (occult rectal prolapse, internal procidentia) can be defined as a funnel shaped infolding of the upper rectal (or lower  sigmoid ) wall that can occur during  defecation . [ 9 ]  This infolding is perhaps best visualised as folding a sock inside out, [ 10 ]  creating "a tube within a tube". [ 11 ]  Another definition is "where the rectum collapses but does not exit the anus". [ 12 ]  Many sources differentiate between internal rectal intussusception and mucosal prolapse, implying that the former is a full thickness prolapse of rectal wall. However, a publication by the  American Society of Colon and Rectal Surgeons  stated that internal rectal intussusception involved the  mucosal  and  submucosal  layers separating from the underlying  muscularis mucosa  layer attachments, resulting in the separated portion of rectal lining "sliding" down. [ 5 ]  This may signify that authors use the terms internal rectal prolapse and internal mucosal prolapse to describe the same phenomena.


Mucosal prolapse  (partial rectal mucosal prolapse) [ 13 ]  refers to prolapse of the loosening of the submucosal attachments to the muscularis propria of the distal rectummucosal layer of the rectal wall. Most sources define mucosal prolapse as an external, segmental prolapse which is easily confused with prolapsed (3rd or 4th degree)  hemorrhoids  (piles). [ 10 ]  However, both internal mucosal prolapse (see below) and circumferential mucosal prolapse are described by some. [ 13 ]  Others do not consider mucosal prolapse a true form of rectal prolapse. [ 14 ]


Internal mucosal prolapse  (rectal internal mucosal prolapse, RIMP) refers to prolapse of the mucosal layer of the rectal wall which does not protrude externally. There is some controversy surrounding this condition as to its relationship with hemorrhoidal disease, or whether it is a separate entity. [ 15 ]  The term "mucosal hemorrhoidal prolapse" is also used. [ 16 ]


Solitary rectal ulcer syndrome  (SRUS, solitary rectal ulcer, SRU) occurs with internal rectal intussusception and is part of the spectrum of rectal prolapse conditions. [ 5 ]  It describes  ulceration  of the rectal lining caused by repeated frictional damage as the internal intussusception is forced into the anal canal during straining. SRUS can be considered a consequence of internal intussusception, which can be demonstrated in 94% of cases.


Mucosal prolapse syndrome  (MPS) is recognized by some. It includes solitary rectal ulcer syndrome, rectal prolapse, proctitis cystica profunda, and inflammatory polyps. [ 17 ] [ 18 ]  It is classified as a chronic benign inflammatory disorder.


Rectal prolapse and internal rectal intussusception has been classified according to the size of the prolapsed section of rectum, a function of rectal mobility from the sacrum and infolding of the rectum. This classification also takes into account sphincter relaxation: [ 19 ]


Rectal internal mucosal prolapse has been graded according to the level of descent of the intussusceptum, which was predictive of symptom severity: [ 20 ]


The most widely used classification of internal rectal prolapse is according to the height on the rectal/sigmoid wall from which they originate and by whether the intussusceptum remains within the rectum or extends into the  anal canal . The height of intussusception from the anal canal is usually estimated by  defecography . [ 11 ]


Recto-rectal (high) intussusception  (intra-rectal intussusception) is where the intussusception starts in the rectum, does not protrude into the anal canal, but stays within the rectum. (i.e. the intussusceptum originates in the rectum and does not extend into the anal canal. The intussuscipiens includes rectal lumen distal to the intussusceptum only). These are usually intussusceptions that originate in the upper rectum or lower  sigmoid . [ 11 ]


Recto-anal (low) intussusception  (intra-anal intussusception) is where the intussusception starts in the rectum and protrudes into the anal canal (i.e. the intussusceptum originates in the rectum, and the intussuscipiens includes part of the anal canal)


An Anatomico-Functional Classification of internal rectal intussusception has been described, [ 11 ]  with the argument that other factors apart from the height of intussusception above the anal canal appear to be important to predict symptomology. The parameters of this classification are anatomic descent, diameter of intussuscepted bowel, associated rectal hyposensitivity and associated delayed colonic transit:


Patients may have associated gynecological conditions which may require multidisciplinary management. [ 5 ]  History of  constipation  is important because some of the operations may worsen constipation. Fecal incontinence may also influence the choice of management.


Rectal prolapse may be confused easily with prolapsing hemorrhoids. [ 5 ]  Mucosal prolapse also differs from prolapsing (3rd or 4th degree) hemorrhoids, where there is a segmental prolapse of the hemorrhoidal tissues at the 3, 7 and 11 o'clock positions. [ 13 ]  Mucosal prolapse can be differentiated from a full thickness external rectal prolapse (a complete rectal prolapse) by the orientation of the folds (furrows) in the prolapsed section. In full thickness rectal prolapse, these folds run circumferential.  In mucosal prolapse, these folds are radially. [ 10 ]  The folds in mucosal prolapse are usually associated with internal hemorrhoids. Furthermore, in rectal prolapse, there is a sulcus present between the prolapsed bowel and the anal verge, whereas in hemorrhoidal disease there is no sulcus. [ 3 ]  Prolapsed, incarcerated hemorrhoids are extremely painful, whereas as long as a rectal prolapse is not strangulated, it gives little pain and is easy to reduce. [ 5 ]


The prolapse may be obvious, or it may require straining and squatting to produce it. [ 5 ]  The anus is usually patulous, (loose, open) and has reduced resting and squeeze pressures. [ 5 ]  Sometimes it is necessary to observe the patient while they strain on a toilet to see the prolapse happen [ 21 ]  (the perineum can be seen with a mirror or by placing an endoscope in the bowl of the toilet). [ 10 ]  A phosphate enema may need to be used to induce straining. [ 3 ]


The perianal skin may be macerated (softening and whitening of skin that is kept constantly wet) and show  excoriation . [ 10 ]


These may reveal congestion and  edema  (swelling) of the distal rectal mucosa, [ 21 ]  and in 10-15% of cases there may be a solitary rectal ulcer on the anterior rectal wall. [ 5 ]  Localized inflammation or ulceration can be biopsied and may lead to a diagnosis of SRUS or colitis cystica profunda. [ 5 ]  Rarely, a  neoplasm  (tumour) may form on the leading edge of the intussusceptum. In addition, patients are frequently elderly and therefore have increased incidence of  colorectal cancer . Full length colonoscopy is usually carried out in adults prior to any surgical intervention. [ 5 ]  These investigations may be used with contrast media ( barium enema ) which may show the associated mucosal abnormalities. [ 10 ]