This subtype is defined by the insertion of the distal rectum into the perineal skin anteriorly to the center of the sphincter complex. The anal opening on the perineum is measured by Hegar dilators typically smaller than appropriate for the child’s age, and/or creates a subepithelial tract ( Fig. 33.1 ). The subepithelial tract may open anywhere along the midline perineal raphe, scrotum, or even at the base of the penis ( Fig. 33.2 ). The diagnosis of this malformation is established by perineal inspection and thorough physical exam.

This drawing shows the course of a perineal fistula in a male. The rectum is located within most of the muscle complex. Only the most distal aspect of the rectum is anteriorly placed in relation to the sphincter complex.

Variations of male rectoperineal fistula presentation with a subepithelial tract filled with either mucus (A), skin (classic “bucket handle deformity”) (B), or meconium (C) that extends into the scrotal raphe.

Courtesy Dr. Marc Levitt.

Anorectal malformation with a rectourethral fistula is the most common malformation in males. The distal rectum, or fistula, inserts into the distal urethra, and the fistula may be located in the bulbar or proximal prostatic urethra ( Fig. 33.3 ). Immediately proximal to the fistula, the rectum and urethra share a common wall.

Anorectal malformation with rectourethral fistulas. (A) Rectourethrobulbar fistula. (B) Rectourethroprostatic fistula.

The more distal the fistula location, the longer the common wall between the rectum and urethra. This vital anatomic fact must be understood prior to operative repair and guides the operative plan. The rectum is usually distended and surrounded laterally and posteriorly by the levator muscle. Between the rectum and the perineal skin, voluntary muscles, called the muscle complex, are present. The contraction of these muscle fibers elevates the skin of the anal dimple. More distal urethral fistulas are typically associated with good-quality muscles, a well-developed sacrum, a prominent midline groove (created by the parasagittal muscle fibers on both sides of the midline), and a prominent anal dimple. More proximal urethral fistulas are frequently associated with poorer-quality muscles, a more abnormally developed sacrum, a flat perineum, a poor midline groove, and a less obvious anal dimple. Occasionally, the infant passes meconium through the urethra. This confirms the presence of rectourinary fistula and is an unequivocal sign of this entity.

The distal rectum inserts at the bladder neck (above the urinary sphincter) on imaging studies ( Fig. 33.4 ). These ARMs carry a less-favorable prognosis for future continence because the levator muscles, the striated muscle complex, and the external sphincter are frequently underdeveloped. The sacrum is often not well formed and short. In fact, the entire pelvis may appear to be underdeveloped (caudal regression). The perineum is often flat, which provides additional evidence of poor pelvic muscle development. About 10% of males fall into this category.

Schematic representation of a rectobladder neck fistula. Note that the fistula enters the bladder neck near the junction between the urethra and the bladder. The rectum enters high above the pubococcygeal (PC) line with the urethra being the first structure encountered in a posterior approach (A), versus the rectum below the PC line as the first structure (B).

ARM without fistula is defined by a blind-ending distal rectum with no communication to the urinary tract or vagina and without a normal anal canal. Most patients with this defect have a well-developed sacrum, good pelvic muscle development, and therefore, often carry good prognosis for future bowel function. The rectum typically ends blindly approximately 2 cm from the perineal skin. Although the rectum and urethra do not communicate, these two structures are separated only by a thin common wall. About half of the patients with no fistula also have Down syndrome, and >90% of patients with Down syndrome and anorectal atresia have this specific defect, ^, suggesting a chromosomal link.

Anal stenosis is defined as a centered anal orifice within the sphincter complex that is measured as too small for the child’s age ( Fig. 33.5 ), with or without a skin-lined funnel-like anal canal. This occurs in <1% of the entire group of malformations. The lumen of the rectum is totally (atresia) or partially (stenosis) interrupted. For rectal atresia, the anal canal is centered within the sphincter complex and there is rectal atresia proximally. The upper pouch is a dilated rectum, and the lower portion empties into a small anal canal that is in the normal location and is 1–2 cm in length ( Fig. 33.6A ). These two rectal structures may be separated by a thin membrane or by dense fibrous tissue. The repair involves a primary anastomosis between the upper pouch and lower anal canal and is ideally approached posterosagittally, with splitting of the anal canal longitudinally ( Fig. 33.6B ). Patients with this defect have all the necessary elements of continence and have an excellent functional prognosis because they have a well-developed anal canal, normal sensation in the anorectum, and normal voluntary sphincters. These patients must also be screened for a presacral mass due to their relative association in Currarino’s triad.

A newborn with anal stenosis[Q3]. Note the normal anal position (A) and the small anal opening (B).

This newborn was found to have rectal atresia. (A) Note the normal anal position and short depth of the anal canal. (B) Operative repair. The anastomosis is to the distal anal canal, preserving the dentate line, which becomes the anterior 180 degrees of the anoplasty.

The distal rectum inserts into the perineal skin (not mucosalized tissue) anteriorly to the center of the sphincter complex ( Fig. 33.7A ), and the opening is smaller than appropriate for the child’s age, and/or creates a subepithelial tract. The rectum is well positioned within the sphincter mechanism, except for its lower portion, which is anteriorly located. The rectum and vagina are well separated ( Fig. 33.7B ). The key anatomic issues are the location of the anal opening in relation to the sphincter mechanism and the length of the perineal body.

Schematic drawing and picture of normal female anatomy. (A) Female neonate with rectovestibular fistula ( arrow ) pointing to fistula. Schematic drawing of a perineal fistula with the entire firstula anterior to the sphincter muscle complex (B), perineal fistula where most of the rectum is in the muscle complex with only the most distal aspect of the rectum is anteriorly positioned (C). Rectovestibular fistula (D).

The distal rectum inserts into the posterior wall of the vagina distal to the hymen, with a typical urethral orifice. Rectovestibular fistula is the most common defect in female patients with ARM and has an excellent functional prognosis. Inspection of the perineum to ensure the normal number of perineal orifices are present is a key portion of any physical exam for the female patient diagnosed with an ARM. Inspection of the genitalia allows the clinician to confirm the presence of a normal urethral meatus, and a normal vagina. In patients with rectovestibular fistula, a third orifice within the vestibule but posterior to the vaginal opening is identified. This opening is the rectovestibular fistula ( Fig. 33.7C ). Approximately 5% of these patients will also have two hemivaginas with a vaginal septum.

The distal rectum inserts into the posterior wall of the vagina proximally to the hymen, with a typical urethral and vaginal orifice. As previously noted, congenital rectovaginal fistula is a relatively rare entity as a newborn diagnosis but can be seen more frequently in infectious settings related to CMV (cytomegalovirus) or HIV (human immunodeficiency virus) infection.

This defect in females carries the same therapeutic and prognostic implications as described for male patients. Anatomically, this diagnosis is characterized by a blind-ending distal rectum with no communication to the urinary tract or vagina and without a normal anal canal. A long common wall with the next most anterior structure (urinary tract in male patients, vagina in female patients) is also present and is important to recognize during surgical repair.

Cloaca is defined by a patient with a single perineal orifice on physical exam between normal or underdeveloped labia with a proximal confluence of the urinary, gynecologic, and gastrointestinal tracts. A cloaca is the extreme in the spectrum of complexity of female malformations. The diagnosis of a cloaca is a clinical one and should be suspected in a female following clinical inspection and identification of a single perineal orifice. The length of the channel from the perineal orifice to the urethral takeoff is called the common channel. The urethral length is the distance from the bladder neck to the insertion of the urethra into the common channel. The length of the common channel can vary, anywhere from 1 to 8 cm ( Fig. 33.8A–C ), and this measurement, along with the urethral length, are the key factors for operative and prognostic implications ( Fig. 33.9 ).

(A) Schematic diagram of a long common channel in a female with a cloacal anomaly. (B) The more commonly encountered short common channel cloaca is depicted. (C) The rectum inserting high into the posterior vagina with a short common urethral and vaginal channel.

(A) Schematic depiction of a cloacal anomaly with insertion of the rectum into the common channel and subsequent vaginal obstruction with hydrocolpos. (B) Schematic depiction of a cloacal anomaly and uterine duplication. The rectum is shown entering between the two hemivaginas.

A thorough and accurate physical exam is of paramount importance for all patients with concern for anorectal malformation. A normal anus is of adequate size, lined by mucosa, has a dentate line, and is located within the center of sphincter complex. The appropriate size of the anal opening is based on age: a newborn should accommodate a size 12 Hegar, while in a one-year-old patient, a 15 Hegar isthought to be adequately sized.

When examining the genital area of a neonatal female, it is optimal to have the patient in the frog-leg position with knees and hips flexed and abducted, or in a supine position. It is important to spread the perineum adequately enough to identify the anatomy. Key anatomical structures should be identified and documented, including three specific aspects related to the anal location: its size, its positioning (centered vs. not centered in the sphincter muscle complex), and the length of the perineal body (distance between the introitus or urinary structures and the anal opening). Identification of a normal urethra and vagina are important and are always part of a comprehensive exam. In some instances, the perineal body may appear short, but the anal opening is still centered within the muscular complex. In unclear cases, an anorectal examination under anesthesia with electric stimulation should be performed to evaluate for perineal fistula and confirm circumferential muscular contractions and a centered anus.

The Currarino triad includes a diagnosis of ARM, typically anal stenosis or rectal atresia, a sacral defect, and a presacral mass. Currarino syndrome (CS) is a syndrome with multiple congenital anomalies that is characterized by partial agenesis of the sacrum in association with pelvic malformation. Inheritance is autosomal dominant. The anus characteristically appears funnel-shaped and is lined with skin. Plain radiographs to evaluate the sacral quality and magnetic resonance imaging (MRI) to evaluate for a presacral mass are important in the evaluation of these children ( Fig. 33.10 ). A presacral mass is found in 90% of cases. Possible masses associated with the Currarino triad include teratomas, meningoceles, dermoid cysts, enteric cysts, and rectal duplications. A spinal cord anomaly, such as tethered cord, is the fourth major associated anomaly and is identified in 70% of cases. Finally, a Mullerian duplication is diagnosed in 70% of females with CS.

Typical sickle-shaped sacrum on abdominal radiograph ( arrow ) (A), infundibular anus (B), presacral mass ( thick arrow ) with tethered cord ( thin arrow ) in Currarino (C).

A decision-making algorithm for the initial management in male infants is seen in Fig. 33.11 . Evaluation of the male newborn with an anorectal malformation begins with a thorough perineal inspection. It is important to defer the determination of initial surgical strategy (either colostomy, a primary neonatal operation, or delayed repair in the presence of a perineal fistula) until around 24 hours of life, as significant intraluminal pressure is required for the meconium to be forced through a fistula. If meconium is seen on the perineum, a rectoperineal fistula is present. If meconium is identified in the urine or emanating from the penis, a rectourinary fistula exists.

Algorithm for the management of male newborns with anorectal malformations based on the physical examination and radiographs.

Radiographic evaluations also may not show the correct anatomy before 24 hours because the rectum is collapsed by the pelvic sphincters. Therefore, imaging studies before that time may show a “very high rectum” and may lead to determination of an incorrect location of the distal rectum. Historically, an invertogram was performed to identify a “high” or “low” anomaly. Currently, we use a cross-table radiograph that shows the height of the rectal air and how close it is to the perineum ( Fig. 33.12 ). This is typically performed around 24 hours of life to ensure the air in the gastrointestinal tract has had sufficient time to distend the rectum after delivery and provide the most accurate location of the distal rectum. This study is performed by placing the patient in the prone position with the bottom elevated to see the column of air within the rectum on radiograph and determine the distance between this column of rectal air and the perineum.

Technique for a cross-table lateral radiograph. (A) A roll has been placed beneath the hips of the infant to elevate the buttocks and allow air to migrate superiorly to the end of the rectum. (B) Actual cross-table lateral radiograph. Air is visualized distal to the coccyx ( arrow ).

During the first day of life, the neonate should receive intravenous fluids, antibiotics, nasogastric decompression, and should be evaluated for associated defects including cardiac malformations, esophageal atresia, and urinary defects. A radiograph of the lumbar spine and the sacrum should be obtained as well as a spinal ultrasound to screen for a tethered cord. Renal ultrasound should be performed to evaluate for hydronephrosis and other urologic anomalies. The renal ultrasound is often deferred until after the first 48 hours of life to ensure adequate evaluation of the urologic system. Echocardiogram is also performed to evaluate for congenital cardiac defects that occur in approximately 10%. Radiographs of the limbs are obtained if there are abnormal physical exam findings.

If a rectoperineal fistula is identified on perineal exam, two common surgical treatment strategies exist. An anoplasty can either be performed in the newborn period if the surgeon is comfortable with neonatal posterior sagittal anorectoplasty. If the perineal fistula opening on physical exam is sized as large enough to pass stool and allow the child to feed and grow in the short term, typically requiring easy passage of a 6 Hegar or larger, repair can be safely deferred for a short period of time and the fistula may be dilated by the parents at home to encourage stool evacuation. Neither of these surgical strategies require a protective colostomy. After 24 hours, if there is no meconium on the perineum, a cross-table lateral radiograph with the patient in the prone position (see Fig. 33.12A ) can show air in the rectum distal to the coccyx (see Fig. 33.12B ). If the baby is in good condition, without significant associated defects, a posterior sagittal operation without a protective colostomy can be considered for surgeons who are comfortable with neonatal posterior sagittal anorectoplasty. If the repair is delayed, it should be performed at or prior to 3 months of age, if possible, to prevent fecal impaction and progressive dilation of the rectum that may complicate future surgical intervention.

If a cross-table radiograph demonstrates the rectal gas proximal to the coccyx, or if meconium is identified in the urine or on the penis, fecal diversion with a colostomy is the preferred initial procedure. Additional features on physical exam that may also direct the surgeon towards colostomy include a flat bottom and poorly formed anal and buttock musculature. An initial colostomy allows for a future distal colostogram. This radiographic study provides more accurate anatomic information about the distal rectum as well as the fistula location. In this scenario, surgical repair can be performed 2–3 months later provided the neonate is gaining weight appropriately.

Performing the definitive repair early in life has important advantages including less time with an abdominal stoma, less size discrepancy between the proximal and distal bowel at the time of colostomy closure, easier anal dilations (because the infant is smaller), and the potential to improve acquired local sensation by placing the rectum in the right location early in life.

Repair of defects with a more proximal fistula and a more proximal rectum without a protective colostomy has been described. ^, However, there are limitations to this surgical strategy. First, a distal colostogram cannot be performed, which is very helpful to the surgeon for precise anatomic information and fistula location that are important for determining the surgical approach. The more common and severe complications often involve infants who have undergone repair without a colostomy or without a properly performed distal colostogram: complications that could potentially have been avoided with more accurate anatomic information. Proceeding with the posterior sagittal approach looking blindly for the rectum without a radiographic map can result in many serious complications including damage to the urethra, complete division of the urethra, pull-through of the urethra, pull-through of the bladder neck, injury to the ureters, and division of the vas deferens or seminal vesicles.

A decision-making algorithm for the initial management of newborn females is shown in Fig. 33.13 . Again, perineal inspection is the most important step to guide diagnosis and operative planning. The first 24 hours should also be used to evaluate for associated defects. The same radiographic and physical exam screening should be performed for female patients as described in male infants. A vestibular fistula represents the most common female anomaly (see Fig. 33.7C ). If a perineal or rectovestibular fistula is identified and the anal fistulous opening is sized as adequate for temporary passage of stool, a similar delayed repair strategy can be employed and has been shown to have similar outcomes when compared to earlier surgical repair. With appropriate pre- and postoperative care, a delayed repair prior to, or around, 3 months of age can be performed without a protective colostomy. When the patient undergoes a primary repair of a vestibular or a perineal fistula without colostomy outside of the neonatal period, a preoperative bowel preparation and a postoperative period with only clear liquids (or breast milk) and no solid foods helps ensure perineal healing.

Decision-making algorithm for female newborns with anorectal malformations.

Perineal inspection may identify a single perineal orifice, which is pathognomonic for the diagnosis of cloaca and carries a high risk of an associated urologic abnormality. Diagnosis of cloaca should prompt complete and timely urologic and gynecologic evaluation, including abdominal and pelvic US to look for hydronephrosis and hydrocolpos ( Fig. 33.14 ).

Hydrocolpos is found on: A severely distended abdomen on physical examination at birth (A), and a plain-film radiograph showing a large opacifying structure with all bowel pushed superiorly, indicating a large pelvic mass (B).

Reprinted with permission from Jacobs SE, et al. Fetal and newborn management of cloacal malformations. Children . 2022;9(6):888.

Hydrocolpos, if present, needs to be addressed in a timely fashion as it typically results in compression of the trigone of the bladder. This causes poor emptying of urine and subsequent dilation of the upper urinary tracts, or hydronephrosis. Drainage of the hydrocolpos is important to allow for decompression of the ureters and resolve any hydronephrosis, thus protecting the kidneys and long-term renal function. Perineal catheterization, or clean intermittent catheterization (CIC), through the single perineal orifice may be effective at draining the hydrocolpos and adequately decompress the renal system, but its success in resolving hydrocolpos and hydronephrosis should be tracked closely and confirmed by ultrasound. ^,

When performing a colostomy for cloaca, if hydrocolpos is persistent it can be drained at the time of surgery. This is best achieved by either a pigtail catheter or by suturing the vagina to the abdominal wall skin as a tubeless vaginostomy. A pigtail catheter can also be placed pre- or postoperatively with image guidance and assistance by interventional radiology. A significant proportion of these patients have two hemivaginas with a septum. Therefore, if performing intraoperative drainage of the hydrocolpos the surgeon must be certain that both hemivaginas are adequately drained to achieve resolution of hydronephrosis and proper urinary drainage. Occasionally, a vaginovaginostomy via the dome of the dilated vaginal structure in the vaginal septum needs to be created to drain both hemivaginas with a single catheter. Rarely, the common channel is very narrow or can be atretic and does not allow the bladder to drain. In these instances, the neonate may require a vesicostomy to decompress the bladder and ensure appropriate urinary drainage. Patients with a cloaca require a colostomy. It is important to perform the divided sigmoid colostomy in such a manner as to leave enough redundant, distal rectosigmoid colon thus allowing for subsequent pull-through ( Fig. 33.15 ).

An ideal colostomy for infants with high anorectal malformations is seen in the drawing (A) and infant (B). Note the colostomy and mucous fistula are separated and that adequate distal colonic length remains for the subsequent rectal pull-through, as well as an intact skin bridge between the incision and colostomy creation.

Prior to reconstructive surgical intervention, endoscopic and radiologic examination of the cloaca is recommended to delineate the anatomy. This is best performed at several months of age during a separate anesthetic due to swelling of the neonatal perineum and difficulty of endoscopy in the newborn. See the surgical intervention section of this chapter for further operative management of cloaca.

In fewer than 5% of girls, there is no visible fistula and there is also no evidence of meconium after 24 hours of observation. Similar to male patients, this small group of patients requires a cross-table prone radiograph (see Fig. 33.12 ). If the radiograph shows gas in the rectum very close to the skin, the baby likely has a very narrow perineal fistula or no fistula. If the baby is in stable condition, a primary operation without a colostomy can be considered by surgeons familiar with this operation. Most of these infants diagnosed with ARM without a fistula also have trisomy 21 syndrome. If significant associated comorbid conditions are identified in the patient with a rectoperineal or rectovestibular fistula that make rectal repair not feasible in the newborn period due to potential clinical instability, the surgeon may elect to dilate the fistula to facilitate emptying of the colon while these other issues are addressed or even place a colostomy if the repair is anticipated to be very delayed. Additionally, if there is a question about the specific details of the anatomy, or the surgeon is not comfortable with neonatal repair, temporary dilations should be considered or a colostomy should be performed, followed by definitive repair, typically when the child is several months old.

For patients with ARM, the goals of stoma with distal mucus fistula placement include diversion of the feces away from the urinary stream, and facilitation of a future distal colostogram for anatomy delineation. It should also be designed to reduce complications like prolapse, stricture, and wound and skin issues such as breakdown and infection. The mucus fistula portion of the colostomy is used for the distal colostogram, which is the critical diagnostic study to determine the distal anatomy, specifically fistula location and its relationship with the bony pelvis and other pelvic structures. ^, During initial ostomy placement, the distal limb of the bowel must be cleared out, ensuring no stool remains. Typically, in an open procedure, separate stomas are made with the proximal bowel placed in the upper left of the incision and the mucous fistula placed lower and medially, ensuring a skin bridge remains ( Fig. 33.15 ). The mucous fistula should be kept flat and small, to preserve distal bowel length. The two openings should be spaced appropriately for an ostomy appliance between the two.

Selecting a stoma location should balance the prevention of issues like prolapse and future reconstruction considerations. To avoid prolapse, the stoma is positioned at the sigmoid colon’s first movable section after the descending portion. A colostomy in the distal sigmoid complicates future pull-through surgery reducing the length of distal bowel available for pull-through without altering the mucus fistula and possibly affecting the distal segment’s blood supply ( Fig. 33.17A and B ). Some believe transverse colon stomas offer flexibility for future reconstructions, but there are challenges, ^, including unintentional sigmoid colostomies placed in the upper right quadrant or issues with obtaining high enough pressure to achieve an adequate distal colostogram. ^, Loop colostomies also may present pitfalls like severe prolapse, stool diversion issues, impactions ( Fig. 33.17C ), and infections. However, when performed correctly, some authors suggest they may have fewer complications.

(A) It is important not to create the colostomy too distal because there will not be sufficient rectal length to allow for the pull-through. (B) This problem is seen on the lateral view of the distal colostogram, where there is insufficient distal rectal length for the pull-through. This is because of an inappropriately placed colostomy and mucous fistula. (C) A markedly dilated distal rectal pouch secondary to fecal impaction can be seen with a loop colostomy.

Adapted from Puri P. In: Newborn Surgery . 3rd ed. CRC; 2012:580.

Laparoscopic divided sigmoid colostomy with a mucous fistula is also an option and if the infant is stable, the stoma should be created before significant abdominal swelling occurs from distal obstruction, usually prior to 48 hours after birth. A 4 or 5 mm port is inserted at the umbilicus, with a 5 mm port at the colostomy site, and 3 mm incisions elsewhere as needed. The sigmoid loop is identified and an ideal location for the stoma site established. The proximal and distal aspects of the colon are confirmed with laparoscopy. The site for the colostomy is brought out onto the abdomen through the 5 mm port site after extension of the incision as needed. The distal bowel contents are irrigated until clean. Laparoscopy can also help verify adequate distal colon evacuation. After bowel division, the distal end is brought out a separate incision, and a corner of the bowel is all that is required to be matured for the future colostogram. The proximal sigmoid stoma is matured. The marginal artery between the two stomas is kept intact when technically feasible.

The importance of preoperative imaging to plan for a successful surgery cannot be emphasized enough. Knowing the location of the fistula and any anatomic associated anomalies identified through appropriate screening and work up can prevent potential surgical misadventures and provides an accurate guide for surgical planning. Misinterpreting the fistula location in children with ARM can lead to significant morbidity. This often arises from reliance on improperly captured images, which the surgeon uses to plan the surgical procedure. The distal colostogram images should be studied by the surgeon to ensure proper distention of the rectum was achieved with the pressure applied.

The conventional high-pressure distal colostogram continues to be the gold standard in determining fistula location and rectal positioning, setting the benchmark for other imaging techniques ( Fig. 33.18 ). More recent imaging options include contrast-enhanced colosonography (ceCS), MRI, ^, and on-table high-pressure colostogram. ceCS uses sulfur hexafluoride lipid-type A microspheres as a contrast, captures ultrasound images without radiation or sedation, but is operator dependent. MRI requires general anesthesia and may not achieve optimal rectal distension.

High-pressure distal colostogram. Auguste Rodin’s Stain John the Baptist sculpture (1880) in the Musee d’Orsay, Paris, France. The right arm is used to represent the course of the male urethra (A). The relative positions of the male urethra represented by the various levels of the arm of the statue. The elbow represents the bulbar urethra junction (B), the humerus represents the prostatic urethra (C), and the axilla represents the bladder neck (D).

Adopted with permission from Halleran DR, et al. A call to ARMs. J Pediatr Surg. 2019;54(8):1708–1710.

In males and females without obvious fistula and a colostomy, a balloon catheter is inserted into the distal mucus fistula. With the balloon inflated in the mucus fistula and below the level of the fascia, injection of contrast medium can be instilled with enough pressure to allow the contrast to flow distal to the levator complex and outline the most distal aspect of the rectum and subsequent rectourethral fistula. A true lateral view is needed to determine the location of the fistula from the tip of the coccyx, to plan for either for a posterior sagittal approach only, or if an abdominal approach is also required. Enough contrast needs to be instilled into the rectum until the connection to the urologic system is delineated. This often requires substantial pressure to distend the rectum and fistula past the levators. The fistula is usually apparent once the child starts to pass urine. An anteroposterior view is also needed to show the length and redundancy of the rectum. Females with rectoperineal and rectovestibular fistulas do not require imaging with contrast study prior to surgery.

In the presence of a colostomy, the posterior sagittal approach should never be attempted without a good high-pressure distal colostogram to determine the exact position of the rectum and the fistula ( Fig. 33.18 ). Attempting the repair without this critical information significantly increases the potential for damage to the bladder neck, urethra, seminal vesicles, ureters, vas deferens, and prostate. A primary advantage of an accurately executed high-pressure distal colostogram is its predictive capability in selecting the best surgical method—either a posterior sagittal or an abdominal technique (laparotomy or laparoscopy), based on whether the rectum is situated above or below the pubococcygeal (PC) line. The pubococcygeal (PC) line is a radiological reference, drawn between the pubis and the distal end of the coccyx on lateral radiographs. Its relevance in surgical planning is determined by the position of the rectum relative to this line. If the rectum lies distal (below) the PC line, a posterior approach is typically recommended. However, if the rectum is positioned proximally (above) the PC line, the urinary tract is usually the first structure encountered, necessitating a laparoscopic or abdominal surgical approach ( Fig. 33.19 ).

Two versions of a rectoprostatic fistula distal colostogram of male patients born with ARM: The pubococcygeal line (PC line, blue line ) is useful in predicting the location of the rectum and surgical approach. If the rectum is the first structure encountered from a posterior sagittal approach, inferior to the PC line, then a posterior sagittal approach is used (A). If the urinary tract is the first structure that would be encountered via a posterior sagittal incision, (i.e., the rectum is encountered proximal/above the PC line) then it is more likely that laparoscopy or laparotomy would be helpful (B).

For patients who have a perineal fistula on physical exam (in male or female patients) or rectovestibular fistula (in female patients), a repair can be performed without a protective colostomy by an experienced surgeon. The advantage of this approach is that it avoids the potential morbidity of a colostomy and reduces the number of operations to one from as many as three (colostomy, main repair, and colostomy closure) decreasing overall potential morbidity for the patient. Many patients do very well with a primary neonatal (or early newborn) operation without a protective colostomy. This approach should be balanced against the potential risk of a perineal infection and dehiscence of the anal anastomosis or perineal body, as well as the comfort level of the surgeon. ^,

It has recently been shown that the complication rate for early (in the first 2 weeks of life) or late primary repair (after 1 month of age) of these types of fistulas is similar and early primary repair can be performed safely. The delayed (vs. neonatal) surgical approach is being adopted more frequently by colorectal surgeons as the tissue of the older infant is more robust and tissue planes may be easier to identify, especially in the setting of a long common wall between either the urethra or vagina for male or female patients, respectively. The decision to perform a colostomy or a primary repair, either in the neonatal or delayed time frame, must be made individually by the surgeon based on their experience and the clinical condition of the patient.