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The basic principles of the posterior sagittal anorectoplasty (PSARP) for the repair of anorectal malformations (ARMs) hold true regardless of the surgical approach. The major advantage of the laparoscopic-assisted anorectoplasty (LAARP) approach is improved visualization of the anatomy, a reduced abdominal and perineal surgical incision length, and avoidance of midline division of the levator muscle complex.
Prior to the selection of the surgical approach, all children born with an ARM require accurate assessment of the anomaly as classified utilizing the Krikenberg classification. The classification assists with ARM reconstructive options as well as guiding discussion of functional clinical outcomes. Workup for associated anomalies includes renal, spine, and cardiac assessment and a search for any additional congenital anomalies (esophageal atresia, duodenal atresia, limb anomalies, etc.). Documentation of the original ARM, the congenital lumbosacral anomalies, and the sacral ratio is important to guide discussions of fecal continence and functional prognosis.
Operative planning and management require imaging to correctly identify the level of the rectum, which guides the surgical approach. The high-pressure distal colostogram can help guide the surgical approach (PSARP vs. LAARP) based on the location of the rectum above or below the pubococcygeal (PC) line. If the rectum is the first structure encountered from the posterior sagittal approach, more success utilizing the posterior-only PSARP approach is likely ( Fig. 16-1 ). During operative construction of the neoanus, frequent use of the muscle stimulator helps identify the muscles and results in correct placement of the neorectum within the sphincter muscle complex. In males, management of a rectourethral fistula requires flush ligation with the urethra to avoid a retained remnant of the original fistula (ROOF). Finally, long-term follow-up and bowel management are required for optimal results.
Indications for Workup and Operation
Indications for the Use of Laparoscopy in Anorectal Malformations
Utilization of laparoscopy for ARMs is most clearly advantageous when the abdominal cavity requires entry. Malformations that require entry into the abdominal cavity include repair of a rectobladder-neck fistula, a high rectoprostatic fistula, a true rectovaginal fistula, and a high rectum in a cloacal malformation, or for planned inspection of Mullerian structures.
Much of the controversy in the surgical approach to ARM repair utilizing laparoscopy centers on repair of the male with an ARM and rectourethral fistula. In this malformation, preoperative imaging with a high-pressure distal colostogram often reveals that the malformation can be most reliably managed using the posterior sagittal approach. When the rectourethral fistula malformation is approached laparoscopically, the dissection poses difficulties as the common wall between the rectum and urethra is long. When the tapered rectum is not dissected flush with the urethra, the result is the premature ligation of the rectum and a ROOF (remnant of the original fistula). A retained ROOF is one of the most common complications when utilizing the LAARP technique for repair of an ARM and rectourethral fistula.
Laparoscopy also is helpful in the surgical approach for females with cloacal malformations, both at the time of operative repair and for additional evaluation of this patient group after puberty. In the neonatal period, a hydrocolpos can be drained utilizing laparoscopy when indicated at the time of colostomy creation. Laparoscopy can also be utilized during primary cloacal repair for mobilization of a high rectum in combination with a PSARP approach. In postpubertal females with previously reconstructed cloacal anomalies, laparoscopy can assist with assessment and treatment of hematometra and obstructed uterine horns. In patients with surgical reconstructions such as bladder augmentation with an umbilical Mitrofanoff and/or right lower quadrant appendicostomy, the use of laparoscopy using a lateral approach and the visualizing trocar/cannula or Veress needle access helps avoid damage to these lower abdominal midline reconstructions.
General Principles When Performing the Colostomy
A proximal sigmoid colostomy should be performed in the newborn with an intermediate or high ARM. The colostomy should be situated in the proximal sigmoid colon. The proximal sigmoid colon is divided so that a 1-cm lip of proximal colon can be exteriorized through the colostomy site in the left abdomen. The sigmoid colon should be divided so that the lateral ligaments to the colon tether the colostomy to help prevent prolapse of the proximal limb. A small enterotomy can be made in the loop to wash out the distal bowel contents. Unfortunately, the distal colon is also prone to prolapse. The incidence of prolapse from the distal colon (mucous fistula) can be reduced by exteriorizing only a small portion of the distal colon staple line from the divided sigmoid colon. The distal mucous fistula should be sited so there is enough length of distal colon to perform the future pull-through without tension. The mucous fistula is situated medial to the more lateral colostomy with intact skin between the two stomas ( Fig. 16-2 ). The opening to the mucous fistula should be no greater than 10 mm and the mucosa is secured flush with the skin. An intact skin bridge allows for the working colostomy to have its own ostomy appliance and avoids breakdown of an incision flush with a colostomy.
General Principles of a Laparoscopic Pull-Through
The principles of the laparoscopic approach consist of mobilizing the distal rectum, ligating/dividing the fistula, bringing the rectum through the muscle complex, and performing the anoplasty by securing it to a small perineal incision at the external sphincter. The operation is carried out with the infant in the dorsal lithotomy position with the legs elevated during the perineal portion of the procedure. The patient is circumferentially prepared with the sterile field encompassing the thorax to the lower limbs. The colostomy is covered with a sterile adhesive dressing.
The abdomen is accessed at the umbilicus. A 5-mm port is introduced and pneumoperitoneum with a pressure of 12 mm Hg is established. Two additional operating ports are then inserted: a 3-mm port or stab incision is situated in the left flank and a 5-mm port is inserted in the right lower quadrant. The 3-mm port allows the introduction of grasping forceps, while the 5-mm cannula allows for the use of the 3- or 5-mm bipolar sealer with Maryland tip (3-mm sealer [Bolder Surgical, Louisville, CO]) or fine hook cautery and facilitates the passage of the needles that are required for suture ligating the fistula. The ability to change the port from a 3- to 5-mm aperture is helpful. Sometimes, it is also helpful to place a retraction suture or instrument (Berchi needle) through a small stab incision in the anterior abdominal wall to elevate/retract the bladder or uterus to improve visualization ( Fig. 16-3 ).