Minimal Access Surgery in the Neonate

Abstract

After completing this article, readers should be able to: Historically, pediatric surgeons were slow to adapt to minimal access surgery (MAS) techniques compared with the adult surgical community. However, MAS now is widely established in infants and children. Differences in size and physiology have necessitated a number of surgical and technological modifications to apply MAS techniques to this population. This review outlines the important differences between children and adults with respect to MAS and provides examples of the use of MAS for diseases seen in infants.The physiologic response to pneumoperitoneum in children is more pronounced than in adults. Peritoneal insufflation with carbon dioxide has been shown to cause hypercarbia, acidemia, and decreased oxygenation in the pediatric piglet model. (1) In infants, however, there is no detrimental effect on blood pressure, heart rate, or oxygen saturation during short periods of pneumoperitoneum, and elevations in end-tidal CO2 can be counteracted readily by increasing the minute ventilation. (2) Hypercarbia-induced pneumoperitoneum in infants is associated with changes in cerebral blood flow and cardiac output. Nevertheless, laparoscopic procedures have been performed safely with proper anesthetic management in children who have even severe congenital cardiac abnormalities such as hypoplastic left heart syndrome. (3) Hypothermia also can be a concern due to rapid insufflation of unwarmed CO2 gas, mandating the moderation of flow rates. (4)A number of anatomic factors set children apart from adults and must be accounted for when performing laparoscopic surgery in this age group. Young children and infants have thinner abdominal walls than adults, so extreme care must be exercised when placing trocars. Due to the small size of the abdomen, the working space is generally smaller, making the choice of trocar sites vitally important. Often very little space is afforded to perform some complex maneuvers. Infants tend to have large livers and spleens, horizontally oriented stomachs, and intra-abdominal (rather than pelvic) bladders, which may limit the intra-abdominal working space further.The early generation of laparoscopic instrumentation was large and difficult to work with in small children (Fig. 1), but there is now dedicated pediatric instrumentation that is significantly smaller than that used in adults (Fig. 2). Although instrument sizes range from 1 to 12 mm and trocar sizes from 2 to 5 mm, neonatal procedures typically use 3.5- and 5-mm instruments. Endoscopes and cameras are lighter, and the shafts of the instruments are considerably shorter, allowing finer manipulation in a smaller space. A radially expanding trocar system has been a tremendous advancement because it allows for a tighter fit in the thinner chest or abdominal wall of the infant and minimizes sliding movement of the ports. Trocar and instrument sizes are selected according to the surgeon’s preference and infant size.Pediatric thoracoscopy has been used in a wide variety of diagnostic and therapeutic procedures, although ventilation has been a considerable obstacle. Because of the inability for double-lung ventilation in smaller children, thoracoscopic procedures often rely on mainstem intubation and low-pressure, low-flow insufflation of the chest cavity to allow adequate visualization of the operative field. Other techniques are available to achieve single-lung ventilation, such as placement of a bronchial blocker or Fogarty catheter in a mainstem bronchus. Controlled pneumothorax can be achieved with low-flow (1 L/min) and low-pressure (3 to 5 torr) CO2 to collapse the lung fully, providing a larger operative space.Minimal access procedures require general anesthesia. Patients are secured to the table, the stomach is emptied by nasogastric or orogastric suction, and the bladder is decompressed by the Credé maneuver. Positioning of the infant is critical to maintain endotracheal tube placement, avoid peripheral nerve injuries, and provide proper access to peripheral intravenous catheter sites and monitoring devices. Increased abdominal compliance allows the use of lower CO2 insufflation pressures in infants. Newborns and infants frequently require only 8 to 12 torr; children and adolescents may require 12 to 15 torr of CO2 pressure for adequate workspace.In contrast to adults, in whom an inguinal hernia may be either direct or indirect, virtually all inguinal hernias in children are indirect, with no inherent weakness or defect in the transversus abdominus or internal oblique muscles. The standard operation for a pediatric inguinal hernia repair involves a groin incision with simple ligation of the sac at the internal ring. Some surgeons have used laparoscopy to identify a patent processus vaginalis on the contralateral side in children who have unilateral inguinal hernias. This was performed initially by placing a small port in the umbilicus, (5) but more recently by passage of a small, 70-degree angled telescope through the sac of the symptomatic side to view the opposite side. (6) Visualizing a patent processus necessitates a contralateral groin exploration.Several techniques for total laparoscopic hernia repair have been described, with the major theoretical advantage being less manipulation of the cord structures and, therefore, less chance of injuring the vas deferens or testicular vessels. (7)(8) We use a technique similar to Harrison and associates, (9) whereby hernial orifices are identified laparoscopically and a nonabsorbable suture on a large needle is passed transabdominally over the internal ring to encircle the neck of the hernia sac. The vas deferens and testicular vessels are excluded from the suture. Once passed back out of the abdominal wall, the suture is tied down, with the knot buried in the subcutaneous tissue. This technique leaves two 3-mm wounds on the abdominal wall (one at the umbilicus) and takes approximately 20 minutes to complete (Fig. 3).Most cases of undescended testis can be treated with orchidopexy, a procedure in which the testis is identified in the inguinal canal through a groin incision and brought down and secured in the scrotum through a scrotal incision. Some testes remain intra-abdominal and cannot be managed with a standard groin orchidopexy because the short testicular vessels limit the surgeon’s ability to place the testis in the scrotum. This problem can be managed using a microvascular anastomosis between the testicular and the inferior epigastric vessels, (10) or more commonly using the two-stage Fowler-Stephens approach (11) in which the testicular vessels are ligated in the first operation to allow for peritoneal and vasal neovascularization, followed by a second procedure several months later in which the orchidopexy is performed. Both of these procedures traditionally have required large groin, scrotal, and abdominal incisions.The current algorithm in the laparoscopic era for undescended testis that is not palpable in the inguinal canal first involves laparoscopy to look for a testis (Fig. 4). If no testis is found intra-abdominally and spermatic cord structures are seen entering the internal inguinal ring, a groin exploration is undertaken. If the testis is seen in the abdomen by laparoscopy, the vessels can be clipped laparoscopically and the subsequent orchidopexy also can be completed laparoscopically. (12) Laparoscopic orchidopexy using a microvascular anastomosis also has been described. (13)Hypertrophic pyloric stenosis occurs in 1 in 400 live births and is characterized by hypertrophy of the pyloric smooth muscle that results in gastric outlet obstruction presenting at approximately 1 month after birth. Following correction of fluid and electrolyte disturbances, patients undergo a Ramstedt pyloromyotomy, in which the pyloric muscle is split while leaving the mucosa intact. The traditional incision has been in the right upper quadrant. Some surgeons prefer a cosmetically superior umbilical fold incision. (14)Laparoscopic pyloromyotomy was first described by Alain and colleagues in 1991, (15) and a number of refinements subsequently have been published. (16) Although some authors have reported a higher-than-expected incidence of mucosal perforation, the results in most series after overcoming the learning curve have been comparable to those after open pyloromyotomy. (17) A meta-analysis of the literature on laparoscopic pyloromyotomy indicates a shorter time to postoperative feeding, which would be expected because there is less manipulation and trauma to the stomach. (18) We employ the laparoscopic “slice and pull technique” similar to that described by Rothenberg in 1997. (19) We introduce a laparoscope through a 3-mm umbilical incision and working instruments through two 3-mm stab incisions in the upper quadrants. A retractable blade is used to perform a longitudinal seromuscular incision, and its blunt end is used in combination with a grasper to complete the myotomy (Fig. 5). The procedure takes an average of 20 minutes, and the infant is generally discharged the next day on full feedings.Minimal access techniques have been used to treat a variety of postnatal pulmonary birth defects, including bronchogenic cyst, congenital cystic adenomatoid malformation, lobar emphysema, and pulmonary sequestration. Low-flow insufflation is used to generate a controlled pneumothorax. Typically, 3- to 5-mm instruments through three or four ports are employed for lung manipulation. A variety of thermal energy sources are used for dissection, such as the ultrasonic dissector or a vessel sealing device. The vessel sealing device can seal and divide vessels less than 7 mm in diameter and can be used to complete fissures. Lobectomy is performed in neonates with minimal morbidity, no need for narcotic analgesia, and hospital discharge within 48 hours. (20) A series of 125 thoracoscopic lobectomies in children were presented at a recent international endosurgery meeting, confirming the safety and efficacy of this procedure. (21)Congenital diaphragmatic hernia is a result of embryologic failure of the pleuroperitoneal membrane to close, resulting in a posterolateral defect (Bochdalek hernia) (Fig. 6), or from failure of the septum transversum to close, resulting in an anteromedial defect (Morgagni hernia). Most Bochdalek hernias present with significant neonatal respiratory insufficiency due to pulmonary hypoplasia, (22) although some smaller defects present later with intestinal symptoms or are discovered incidentally. (23) Morgagni hernias are less common and usually present beyond the neonatal period.A diaphragmatic hernia traditionally is repaired after stabilization of the child, using a subcostal incision. Primary repair always is attempted, and either a synthetic patch or internal oblique muscle flap may be used for larger defects that cannot be closed. Minimal access approaches have been used for both Bochdalek and Morgagni diaphragmatic hernias; the former have been approached both thoracoscopically and laparoscopically and the latter only laparoscopically. If necessary, a synthetic patch can be placed using either the laparoscopic or thoracoscopic approach. Initial reports included only children beyond the neonatal period, (24)(25) but several authors have reported neonatal cases recently. Special caution must be used in infants receiving extracorporeal membrane oxygenation, high-frequency ventilation, or high peak airway pressures due to their physiologic fragility and potential for extreme hypercarbia. Such infants must be individually considered for MAS.Unilateral diaphragmatic eventration is a permanent elevation of the normally attached musculature, either as a result of phrenic nerve injury (eg, following cardiac surgery) or as a congenital problem. Diaphragmatic weakness and paradoxic motion of the affected side during respiration produces a decrease in expiration and inspiration, leading to respiratory insufficiency that requires surgical correction. The diaphragm typically is reduced in thickness and is without other defects. Suture plication can be performed, using either a laparoscopic or thoracoscopic approach, and results in immediate resolution of symptoms.One of the most recent evolutions in pediatric minimally invasive surgery has been the application of thoracoscopic techniques to esophageal atresia with distal fistula. Traditionally, the surgical approach involved a right thoracotomy, fistula ligation, and a primary esophagoesophagostomy. Apart from the postoperative pain associated with a thoracotomy, reported long-term morbidity includes winged scapula, chest wall disfigurement, fusion of the ribs with respiratory dysfunction, thoracic scoliosis, fixation of the skin cicatrix to the bony thorax that limits mobility of the ipsilateral shoulder, and disfigurement of the right breast from the thoracotomy scar. (26)In recent years, a number of reports have described total thoracoscopic repair of esophageal atresia (Fig. 7). (27)(28) This procedure usually is performed using a three-port (two 3-mm and one 5-mm) approach in conjunction with 4-mm Hg CO2 pleural space insufflation at a low-flow rate.A recent meta-analysis of 104 thoracoscopic repairs from multiple institutions showed an 11.5% early leak or stricture rate, 1.9% rate of recurrent fistula, and one patient mortality related to the atresia. (29) These results are comparable to outcomes reported for patients who had repair through thoracotomy, with the added benefit of avoiding the morbidity of a thoracotomy. This procedure is particularly challenging from a technical point of view and likely will become more widespread as robotic and other surgical device technologies evolve.Hirschsprung disease is characterized by distal colonic aganglionosis that results in functional obstruction. Preoperative management includes confirmation of disease by rectal biopsy, rectal decompression and dilation, rectal irrigation, and preoperative antibiotics. Surgical management traditionally has involved two or three stages, with an initial diverting colostomy. A combined abdominal and perineal approach was used to resect the aganglionic bowel and anastomose the normally innervated bowel to the anus. Variations on this operation include the Swenson, Soave, and Duhamel procedures. More recently, many authors have advocated a one-stage operation without a preliminary stoma. (30)In 1995, Georgeson reported a one-stage minimal access approach to Hirschsprung disease using laparoscopic mobilization of the rectum combined with a perineal submucosal dissection. (31) This technique resulted in earlier feeding and decreased hospital stay and has been adopted by a large number of other centers. (32) Subsequently, a number of authors described a similar procedure using a purely transanal approach, (33)(34)(35) which has the advantage of avoiding the need for laparoscopic dissection and can be performed by surgeons who are not skilled in or do not have access to laparoscopic surgery (Fig. 8). Some surgeons have used laparoscopy or a small umbilical incision to identify the transition zone histologically prior to beginning the perineal dissection. (36) When compared with open procedures, both the laparoscopic and transanal techniques result in less pain, shorter hospitalization, and lower cost. (16)(37)Imperforate anus constitutes one end of the spectrum of anorectal malformations, in which there is absence of an anal opening, usually associated with a rectourethral or rectovaginal fistula. This condition frequently is associated with one or more other conditions such as vertebral, cardiac, tracheoesophageal, renal, and radial limb anomalies, giving rise to the VACTERL association.Posterior sagittal anorectoplasty, consisting of an incision from the coccyx to the perineal body with exposure of the external sphincter, levators, rectum, and fistula, is currently the most commonly performed procedure for imperforate anus. (38) With this approach, the sphincter complex is divided in the midline, the fistula is ligated, the rectum is pulled down and anastamosed to the center of the sphincter complex to form a neoanus, and the sphincter complex is reconstructed.In 2000, Georgeson and colleagues described a minimal access procedure for the repair of imperforate anus. (39) A laparoscopic approach is used to dissect the rectal pouch down to the fistula, which then is clipped and divided. As the rectum is mobilized from the pelvic floor, the underlying levator muscles are visualized. With sufficient muscle mass, the midline can be identified within the pubococcygeus muscles. The midline also can be identified from the position of the urethra and the divided fistula if the muscle mass is insufficient. Transcutaneous electrostimulation is used to define the center of the sphincter complex at the anal dimple, and this site is marked with an 8-mm vertical midline incision. A trocar with a radially expandable mesh sheath over a Veress needle is passed through the incision and advanced between the two bellies of the pubococcygeus muscle in the midline posterior to the urethra with laparoscopic guidance (Fig. 9). This ensures placement of the orifice in the midline and within the external sphincter. When expanded to a diameter of 12 mm, the trocar effectively forms a passage for the blind-ending rectum, which is grasped and pulled through with an instrument passed through the trocar. The rectum is anastomosed to the skin to create a neoanus and retracted laparoscopically cephalad and sutured to the presacral fascia to avoid prolapse.This procedure avoids an extensive perineal incision, prevents the need for division of the sphincter complex, and permits excellent visualization of the pelvic anatomy. The approach may be particularly useful for children who have high fistulas into the bladder neck or prostatic urethra. The operation can be performed with or without a preliminary colostomy. (40) Early results are encouraging, but long-term measurement of continence is necessary to evaluate this technique fully.Intestinal rotation abnormalities are defined as incomplete embryologic rotation of the duodenum and cecum around the superior mesenteric vessels. There is a spectrum of conditions, ranging from nonrotation to normal rotation. The most clinically important form is classic malrotation, in which the cecum and the duodenojejunal junction both sit in the mid-upper abdomen, creating a narrow-based small bowel mesentery that may lead to midgut volvulus and intestinal necrosis. In contrast, both nonrotation and normal rotation are associated with a longer mesenteric base that is not associated with volvulus.Malrotation is treated with the Ladd procedure, an operative sequence involving detorsion of the midgut if volvulus is present, mobilization of the colon to the left and the duodenum to the right, widening of the mesenteric base, and appendectomy, leaving the intestines in a position of nonrotation (duodenum and small bowel on right, cecum/colon on left). This operation traditionally is performed through a right upper quadrant transverse incision.A number of authors have described a laparoscopic approach to the Ladd procedure, with and without midgut volvulus, (41)(42)(43) although most surgeons still favor an open approach in a child who has clinical features suggestive of advancing intestinal ischemia. In these studies, the laparoscopic approach has been associated with early feeding, short hospital stay, and minimal pain.Some children have an intestinal rotation abnormality in which the length of the mesenteric base is not clear from radiologic studies (ie, not classic malrotation). Laparoscopy provides excellent visualization of the mesenteric base; in those who have a narrow base, a laparoscopic Ladd procedure can be performed, and in those who have a broad-based mesentery, nothing further need be done.Many surgeons believe that adhesions play a significant role in preventing volvulus after a Ladd procedure and have expressed concern that the lack of adhesions following laparoscopy may result in recurrent volvulus. Long-term follow-up studies are necessary to address this issue, although it has not emerged as a problem to date.Biliary atresia is a neonatal condition characterized by progressive inflammatory obliteration of the extrahepatic biliary ductal structures, progressing to cirrhosis and liver failure if left untreated. Surgical management involves resection of the atretic bile duct with Roux-en-Y portoenterosotomy to provide a biliary drainage conduit for the microscopic biliary radicles at the hilar plate (the Kasai operation). Although most patients subsequently develop liver failure and require transplant, approximately 30% have long-term relief of their biliary obstruction. (44)These operations are technically challenging and traditionally are performed through a wide right subcostal incision. A number of authors have reported laparoscopic approaches to the Kasai portoenterostomy. (45)(46)(47) We also have used the surgical robot for portoenterostomy (Fig. 10). Potential benefits to a laparoscopic approach include the avoidance of a large and painful incision, high magnification view of the hilar dissection, and avoidance of excessive scar tissue that may interfere later with hepatic transplantation. In our institutional experience, liver resection for transplant after a laparoscopic portoenterostomy has revealed reduced adhesions around the dome of the liver but not so around the Roux limb and porta hepatis. Consequently, dissecting the Roux limb away from the portal vasculature has been as difficult as after open portoenterostomy, although dissection around the cava and hepatic veins is simplified.Patent ductus arteriosus (PDA) in the newborn causes left-to-right shunting, with pulmonary overcirculation and left ventricular overload, and can lead to pulmonary vascular disease, congestive heart failure, and the potential for bacterial endocarditis. (48) The first successful ligation of a PDA was performed by Robert Gross in 1939, (49) and this has remained a common surgical procedure in both neonates and older children. The operation is performed through a left posterolateral thoracotomy, which is accompanied by the same long-term morbidity as described previously.Two minimal access approaches have been developed to deal with this problem: one by interventional cardiologists and the other by minimal access surgeons. Interventional cardiologists use an intravascular catheter to deliver a polyvinyl alcohol foam plug, or more recently, stainless-steel spring coils to act as the occluding device. (50) Coils have a complete occlusion rate of 89% to 93% at 4 to 24 hours postprocedure and 98% at 6 months. The inadvertent embolization rate is 3%, but the coils can be retrieved. (51)In an initial attempt to minimize the trauma of a thoracotomy, a transaxillary muscle-sparing lateral thoracotomy using a 3- to 4-cm incision was developed for PDA ligation. (52) To minimize incision size further, a number of authors have performed thoracoscopic PDA closure. (53) The PDA is ligated with two titanium clips through the posterior trocar, using a 5-mm clip applier. A chest tube is placed as needed. This approach also has been described in low-birthweight infants (575 to 2,500 g). (54)The introduction of robotic surgical technologies (Fig. 11), with their potential for improved optics and instrument dexterity, has added a new dimension to MAS. Featuring wristed instrumentation with additional degrees of freedom (Fig. 12) compared with standard laparoscopic instruments, stereoscopic (three-dimensional) visualization, nonreversed instrument control, tremor reduction, and motion scaling, robotic systems attempt to address many of the limitations of standard laparoscopic techniques. A wide variety of pediatric surgical procedures have been performed with the surgical robot, including fundoplication, repair of Morgagni hernia, splenectomy, cholecystectomy, appendicovesicostomy, PDA repair, Heller myotomy, and portoenterostomy, among others. (55) Its application in the infant population will evolve as miniaturization of the robotic arms becomes possible.Surgical intervention for fetal abnormalities has developed over the past few decades as imaging techniques and our understanding of the physiology of the anomalies has improved. Many interventions have involved placing shunts into an obstructed bladder, cystic lung lesion, or fetal hydrothorax under ultrasonographic guidance. More recently, the development of small endoscopes has permitted telescopic visualization of the fetus and the use of laser coagulation to manage twin-twin transfusion and other conditions. (56) “Fetendo” surgery also has been used to perform tracheal occlusion for fetuses that have congenital diaphragmatic hernia and to divide fibrous bands in pregnancies complicated by amniotic band syndrome. (57)