Georgeson's procedure: Laparoscopically assisted anorectoplasty for high anorectal malformations

Abstract

Minimally invasive options for correction of many surgical conditions seen in infants and children have become available and primary advantages seen with minimally invasive methods derive from the surgeons ability to perform procedures within the bodys major cavities with the least amount of iatrogenic injury to intervening skin, fascial, muscular, and nervous tissues (Dick et al. 1998; Kehlet and Nielsen 1998). The ability to perform reconstructive surgery with minimal trauma is especially relevant and important for the neonate with an anorectal malformation, since the intervening tissues must perform sensory and contractile functions critical for lifelong control of continence. For many decades, the infant born with a high anorectal malformation (ARM) has represented a management challenge for pediatric surgeons and parents alike. Operative reconstruction of high ARM is a demanding and meticulous undertaking, and, despite the careful and deliberate technique of an experienced pediatric surgeon, functional outcomes are far from perfect. In the early 1990s, a minimally invasive technique for correction of high ARM was developed by Keith Georgeson-the laparoscopically assisted anorectoplasty (LAARP). His early surgical experience with LAARP was first presented at the surgical section meeting of the American Academy of Pediatrics in October of 1998 (Georgeson et al. 2000). Since that time, many other centers have gained experience with this minimally invasive technique, and have confirmed the merits of the approach to this complex and difficult malformation. This chapter will represent a current update of the technique of minimally invasive correction of high ARM. Over the years, we have learned that muscles deep within the pelvic floor are critical to continence by virtue of their sensory as well as motor function. Before the 1950s, if reconstruction of patients with high ARM was attempted at all, it was done by way of laparotomy and a limited perineal incision (abdominoperineal pull-through). Surgeons used a blind, blunt dissection through the pelvic floor toward the perineum. It is not difficult to imagine the challenges which faced the operative team at that time, which included poor ability to visually inspect the depths of the infant pelvis, the real concern for eliciting hemorrhage in an area which would be difficult to easily control, and the imprecise guidance of the dissection using tactile sense. Due in part to the anterior lie of the central portion of the puborectalis sling in the patient with ARM, this critical element controlling fecal continence was often completely disrupted by blind pull-through. Important concepts (which would contribute to modern thinking) were inspired by the work of Douglas Stephens in the premodern era (Stephens 1953). His seminal contribution, which began in the early and mid 1950s, was to recognize the importance of preservation of the integrity of the pelvic levator musculature (the puborectalis muscle in particular) and external anal sphincters. His important principles-to minimize surgical trauma and thus preserve the integrity of the muscles of continence by using alternative strategies for visualization of the pelvic floor-are still emphasized today. Specifically, Stephens aimed to improve surgical results by improving the quality of the surgical dissection of the pelvic passage for rectal pull-through. Thus was born the sacroperineal pull-through procedure (Fig. 54.1), and variations thereof. With a transverse (Figure presented) sacral incision, superoposterior to and separate from the perineal incision for anorectal anastomosis, the hope was that the surgeon could more accurately negotiate the minute and delicate pelvic floor components and place the pull-through rectum more correctly through the midline center of the levators while anterior to the central belly of the puborectalis muscle. Although surgeons of this era clearly had intended to better visualize and preserve the structures critical to continence, unfortunately, the tools and access approaches available were still unsuitable for the exacting task. A major revolution in thinking about ARM repair came in the early 1980s when Pena and DeVries introduced an operative approach that has been considered the most important advancement in the management of the entire spectrum of ARMs (de Vries and Pena 1982). The posterior sagittal anorectoplasty (PSARP) allowed surgeons the ability to accurately place the bowel within the confines of the levator complex as well as the more distal striated muscle complex contiguous with the external anal sphincter. This technique quickly supplanted other contemporaneous operations, in large part due to its simplicity and elegance (Fig. 54.2). In the prelaparoscopic era, the visualization afforded to the surgeons who used this procedure was unparalleled. Pena and others noted an improvement in functional outcome after PSARP and credit that functional improvement to the fact that the muscles of continence are not destroyed during the procedure, rather these structures are surgically separated or divided and ultimately reapproximated during reconstruction. Indeed, this operation has endured the all important test of time, being the dominant procedure since the 1980s. There are many manuscripts and chapters devoted to every detail of this operation and a recent update of the experience with PSARP (Pena and Hong 2000). With this procedure, Pena has made a fundamental contribution to our understanding of high ARM. He showed that dissection through the external anal sphincter complex and complete surgical division of the levator muscles in the midline can be performed without destroying these important structures. Indeed, if the operation is performed well, 30-50% of patients with high ARM can be completely continent, and most of the remainder can be made socially continent. However, although the results of PSARP represent an improvement over prior operations, there remains some uncertainty as to the extent to which (1) the inherently abnormal bowel and sphincter function or (2) the dissection technique of PSARP (with division and reconstruction of the muscles critical for fecal control) contribute to the high rates of incontinence following PSARP for high ARM. This important question provided us with the rationale to consider the possibility of accomplishing a correction of high ARM without midsagittal division of any of the muscles of continence (Georgeson et al. 2000). If one of the most important advances inherent in the PSARP was that of exquisite visualization of the pelvic structures of continence, Georgesons procedure for reconstruction of high ARM provides an even greater advantage of exquisite visualization of the intrapelvic anatomy. The angled laparoscope used in Georgesons procedure enables the surgeon to visualize in magnified detail the critical pelvic musculature. Unlike the PSARP, the vantage point for this visualization is internal, rather than external as with PSARP. Thus, with the laparoscope, the pediatric surgeon can see well within the depths of the neonatal pelvis, behind the neck of the bladder. Inspection of the pelvic floor and visualization of the individual muscles constituting the levator complex is possible. From this point of view, guidance of the dissection from perineum is precise, and any deviation from the desired path of dissection is instantaneously identified and corrected.