Fig. 36.1.
Contrast enema post evacuation phase demonstrating the transition zone (arrows). The aganglionic Hirschsprung’s bowel is distal to the transition zone (TZ—transition zone), which is less than 5 cm in length in most cases.
Treatment
Traditionally, surgical treatment for Hirschsprung’s disease was performed in two or even three stages. A leveling colostomy was done in the first stage, and this was subsequently reversed at a later time. Today, with advances in surgical techniques and perioperative management, surgery in uncomplicated cases is usually done as a single stage via minimally invasive approaches [24–27]. During the operation, frozen section seromuscular biopsies as well as the final doughnut are sent to determine the proximal margin of the resected segment. Care must be taken to resect all the abnormally innervated bowel including the transition zone bowel.
Surgical Techniques
Three surgical options were originally described to treat HD. The Swenson procedure involves excising the full-thickness aganglionic segment of bowel to the level just proximal to the internal sphincter and performing a colo-anal anastomosis. In the Soave procedure, the aganglionic segment is removed, but only the mucosa is resected from the aganglionic rectum. The normally ganglionated proximal bowel is then pulled through the split muscular cuff and a colo-anal anastomosis is created. The Soave procedure avoids any pelvic dissection and associated complications, such as pelvic nerve damage, seen with the Swenson. In the Duhamel procedure , the full-thickness rectal stump is left in place. The normal proximal bowel is pulled down posteriorly in the retrorectal space. A stapler placed through the anus is then used to create a side-to-side anastomosis. In this neorectum, the anterior wall is comprised of the aganglionic native rectum, and the posterior wall is normally innervated proximal bowel. This functional composition of the neorectal reservoir is intended to provide a more natural emptying mechanism, especially in cases of long-segment Hirschsprung’s disease when the ileum may have to be pulled through. These original procedures have evolved into the modern era of surgery, and they are now frequently performed via transanal and/or laparoscopic approaches or a combination of both [2, 22].
Laparoscopic-Assisted Transanal Pull-Through (Georgeson/Soave Technique)
Appropriate Patient Selection
The diagnosis of HD must be confirmed by an experienced, reliable pathologist with a rectal biopsy. This technique is best suited for short-segment disease, and ideally the patient would have a barium enema study demonstrating a distal transition zone. Longer segment disease is a relative contraindication for this surgical option, and these patients may be better served by a Duhamel procedure l. Prematurity is a relative contraindication, as these patients may not have fully mature ganglion cells and histologic evaluation of biopsies may therefore not be reliable. The patients are managed with rectal stimulation and irrigation until term. Strict contraindications include significant malnutrition, active enterocolitis, or massively dilated proximal bowel; these patients should undergo a staged procedure, with an initial colostomy and a definitive operation once the contraindication has resolved.
Preparation
Preoperative antibiotics are given to cover gram-negative and anaerobic organisms. Surgical Care Improvement Project (SCIP) guidelines should be followed. Some surgeons recommend on-table colonic and rectal lavage with warm, diluted Betadine solution via a red rubber catheter. A formal preoperative bowel preparation is not recommended due to the presence of functional distal obstruction.
The procedure is performed with the patient under general anesthesia in the lithotomy position. A sterile circumferential lower body preparation is used. No IVs or lines should be in the lower extremities. After the prep, a urinary catheter is placed sterilely.
Laparoscopic-Assisted Leveling Biopsy
Prior to beginning the transanal portion of the operation, the exact location of the transition zone must be confirmed. Laparoscopy offers an efficient and minimally invasive approach to this step. One camera port and two working ports are placed on the right side of the abdomen and pneumoperitoneum is established (Fig. 36.2). The descending and sigmoid colon are visualized to identify the transition zone, which can be difficult to reliably see in neonates. A Hegar dilator placed transanally may facilitate elevation and manipulation of the sigmoid colon during this step.
Fig. 36.2.
Sterile lower body preparation with typical instrument position for laparoscopically assisted pull-through procedure . An additional 3 mm instrument may be placed transabdominally in the left upper quadrant for retraction if more extensive mesocolonic dissection for a longer segment of aganglionated colon becomes necessary (from http://www.clsnyder.com/WordPress/2008/05/19/hirschsprungs-disease-lap-assisted-transanal-pullthrough-tutorial/).
A biopsy site is then chosen 2 cm proximal to the assumed transition zone, on the anti-mesenteric side of the colon. A “knuckle” of bowel is then grasped with Maryland forceps. Using scissors, a partial-thickness, seromuscular biopsy is taken (Fig. 36.3). Some surgeons prefer to take full-thickness biopsies on request of their pathologists; however, there currently is no definitive evidence that either of these strategies is superior. A stitch may be warranted to repair the defect at the biopsy site, in order to prevent contamination of the peritoneal cavity during the case. The biopsy is then sent for frozen section examination by the pathologist. While this is being done, the mesentery of the colon distal to the biopsy site can be taken down, staying close to the bowel (Fig. 36.4). If the pathologist cannot confirm normal ganglion cells and nerve fibers, additional biopsies will need to be taken, marching proximally until a normally ganglionated bowel with normal nerve fibers is found. Care must be taken to include transition zone bowel with some, but not all, completely normal ganglion cells into the pull-through. In most cases, the transition zone is less than 5 cm in length.
Fig. 36.3.
Using scissors, one or two partial-thickness, seromuscular biopsies are taken. Some surgeons prefer to take full-thickness biopsies on request of their pathologists. The biopsy site should be closed with a figure-of-eight suture to prevent contamination and mark the area during the pull-through (Courtesy of Marcus D. Jarboe, MD, C.S. Mott Children’s Hospital, University of Michigan, Ann Arbor, MI, USA).
Fig. 36.4.
Laparoscopic mesocolic dissection using the Maryland-shaped LigaSure device while awaiting the frozen section result of the colon biopsy. Alternatively, monopolar hook cautery works well for infants (Courtesy of Marcus D. Jarboe, MD, C.S. Mott Children’s Hospital, University of Michigan, Ann Arbor, MI, USA).
All mesenteric attachments are divided up to the confirmed normal colon. If there is concern that there is not enough length to reach the anus, the lateral peritoneal attachments to the colon along the white line of Toldt can be taken down laparoscopically, including the splenic flexure if necessary. While waiting for the frozen section of the biopsy specimen to confirm anatomically normal colon with ganglion cells and nerve fibers, the mesocolon can be dissected distal toward the rectum using the monopolar hook cautery or the JustRight bipolar dissector (JustRight Surgical, LLC, Louisville, CO). The mesenteric vessels should be divided proximal to the marginal arteries, thereby gaining length while maintaining perfusion through this collateral arcade. The pelvic peritoneal reflection can be dissected to facilitate the transanal portion of the surgery. In some cases, when the biopsy specimen shows transition zone bowel, an additional, more proximal biopsy has to be taken. Once the leveling biopsy site has established normal colon, the abdomen is desufflated and attention is turned to the perineum. Some surgeons prefer to continue with laparoscopic “full-thickness” proctectomy in the Swenson plane into the lower pelvis before turning to the transanal portion of the case (Fig. 36.5).
Fig. 36.5.
After the laparoscopic mesocolic dissection has been performed, the pelvic peritoneal reflection can be divided. Some minimally invasive surgeons who prefer a Swenson-type full-thickness proctectomy perform part or most of the proctectomy laparoscopically instead of solely through the anus. Adapted from Technical modification of the Georgeson procedure for Hirschsprung’s disease: a 12 Years experience with the laparoscopic-assisted mesocolon dissection. Ruggeri G, Randi B, Gargano T, Libri M, Maffi M, Lima M. JEMIS – Journal of Endoscopic, Minimally Invasive Surgery in Newborn, Children and Adolescent – ISSN 2283–7116 (DOI: http://dx.medra.org/10.1473/JEMIS14)).
Transanal Pull-Through
The operating surgeon sits at the foot of the bed. Visualization may be augmented with Trendelenburg positioning and the use of a headlight. The anal canal is everted using either the Lone Star retractor or interrupted silk sutures, depending on surgeon preference. The squamocolumnar transitional epithelium, or dentate line, is identified. It is crucial that this transitional epithelium remains intact (Fig. 36.6). A nasal speculum is inserted into the anus to provide exposure. Using needle-tip electrocautery, a circumferential mucosal incision is made 0.5 cm above the dentate line in infants; for older children, a 1-cm margin is advised. The mucosal dissection is carried proximally for approximately 2 cm, staying within the relatively avascular submucosal plane (Fig. 36.7). Stay sutures placed in the mucosa may be helpful to aid with retraction during dissection. This step creates the mucosal resection within the muscular rectal cuff as described in the original Soave procedure. The dissection then proceeds toward proximal between mucosal and muscular plane of the rectal wall. Once the peritoneal reflection is reached, a circumferential incision is made through the outer muscular and serosal layers of the rectal wall into the abdominal cavity of the upper pelvis (Fig. 36.8). At this point, the rectal mucosal tube and the previously mobilized sigmoid colon are freely mobile. The entire colorectal specimen is then pulled through the rectal muscular cuff and out of the anus until the leveling biopsy site is reached, taking particular care to avoid rotation (Fig. 36.9).
Fig. 36.6.
Start of the transanal part of the minimally invasive pull-through procedure (Soave or Swenson). A Lone Star retractor is used to evert the anus and visualize the dentate line. Retraction sutures are placed in the rectal mucosa 1 cm above the dentate line. It is very important to make an incision with appropriate distance proximal to the dentate line since injury of the dentate line may lead to fecal incontinence later. Please note that this picture was taken from a completely transanal procedure without laparoscopic portion, and the patient is in a prone position (Courtesy of Luis de la Torre, MD, Pediatric Colorectal Surgery, Children’s Hospital of Pittsburgh, Pittsburgh, PA, USA).
Fig. 36.7.
Transanal rectal mucosectomy (Soave procedure ) with dissection plane between rectal mucosa and submucosa/muscularis. Please note the hooks of the Lone Star retractor were advanced into the proximal aspect of the dentate line for exposure. The mucosal incision is well above the dentate line. For the Swenson procedure, the initial incision traverses the full-thickness rectal wall with the dissection plane just outside of the rectum (Courtesy of Luis de la Torre, MD, Pediatric Colorectal Surgery, Children’s Hospital of Pittsburgh, Pittsburgh, PA, USA).
Fig. 36.8.
Transanal dissection above the pelvic peritoneal reflection after division of the submucosal/seromuscular layer of the distal colon (Courtesy of Luis de la Torre, MD, Pediatric Colorectal Surgery, Children’s Hospital of Pittsburgh, Pittsburgh, PA, USA).
Fig. 36.9.
The complete transanal specimen prior to colo-anal anastomosis. Before the anastomosis is fashioned, the proximal doughnut of the resected colon is given to the pathologist to evaluate for an anatomically normal bowel (Courtesy of Luis de la Torre, MD, Pediatric Colorectal Surgery, Children’s Hospital of Pittsburgh, Pittsburgh, PA, USA).
Before anastomosis, a posterior myotomy of the rectal muscular sleeve, which remains after the Soave procedure, must be performed. Some surgeons remove about one quarter of the muscular sleeve posteriorly to prevent re-scaring and recurrence of a tight muscular rectal cuff (Fig. 36.10). A final laparoscopic look can be performed before completion of the anastomosis to verify the correct non-rotated position of the pulled-through colon (Fig. 36.11).
