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MALROTATION
chapter 32
MALROTATION Danny C. Little, MD • Samuel D. Smith, MD
rotation of the human intestine requires N ormal transformation from a simple, straight alimentary tube into the mature fixed and folded configuration present at birth. Through precise embryologic events, the duodenojejunal junction becomes fixed in the left upper abdomen while the cecum is anchored in the right lower quadrant. The midgut, defined as the portion of the intestine supplied by the superior mesenteric artery, is thus suspended from a wide mesenteric base. In children with malrotation, the bowel is not fixed adequately and is thus held by a precariously narrow-based mesentery. Rotational anomalies create a spectrum of anatomic conditions with critical importance to the pediatric surgeon. Clinical disorders may arise when intestinal rotation either fails to occur or is incomplete. Rotational anomalies may be isolated or occur as an intrinsic component of gastroschisis, omphalocele, or congenital diaphragmatic hernia. Additionally, malrotation may present as an incidental, subtle finding discovered during the radiographic evaluation of another diagnosis or with septic shock from a catastrophic midgut volvulus. The earliest descriptions of intestinal development were from Mall in 1898 and later expanded upon by Frazer and Robbins in 1915.1,2 Eight years later, Dott translated these preliminary embryologic observations into problems encountered clinically.3 In his 1932 landmark surgical paper, Ladd described the evaluation and surgical treatment of malrotation.4 He described a relatively simple solution to a complicated problem. In his 1941 textbook entitled Abdominal Surgery of Infancy and Childhood, Ladd warned that unfamiliarity with this lesion would quickly lead to surgical confusion.5 Over 200 postmortem studies had been reported previous to Ladd’s paper, yet he was the first to emphasize the importance of placing the duodenum along the right abdominal wall, widening the mesenteric base, and moving the cecum to the left upper abdomen. With the exception of the laparoscopic approach, the original Ladd procedure has remained relatively unchanged. 416
EMBRYOLOGY The development of the midgut begins with the differentiation of the primitive intestinal tract into the foregut, midgut, and hindgut at the fourth week of gestation.6 The mature alimentary tract and all associated digestive organs are formed from this primitive tube. The most accepted model of midgut maturation involves four distinct stages: (1) herniation, (2) rotation, (3) retraction, and (4) fixation. Normal fixation of the duodenum and colon is illustrated in Figure 32-1. The intestinal loop can be divided into the cephalic (duodenojejunal) limb and the caudal (cecocolic) limb, which rotate separately but in parallel. The superior mesenteric artery serves as the fulcrum with the omphalomesenteric duct at the apex. Because of disproportional growth and elongation of the midgut during the fourth gestational week, the intestinal loop herniates into the extraembryonic coelom. Next, the bowel enters a critical period of rotation when the prearterial and postarterial limbs make three separate 90-degree turns, all in the counterclockwise direction around the superior mesenteric artery. The first 90degree rotation occurs outside the abdomen. The second 90-degree rotation commences during the return of the intestine into the abdominal cavity during the 10th gestational week. The duodenojejunal junction now passes posterior to the superior mesenteric artery. The last rotation occurs in the abdomen. The primitive intestine has thus completed a 270-degree counterclockwise rotation, allowing the duodenojejunal limb to be positioned to the left of the superior mesenteric artery while the cecocolic limb is on the right. Fixation of the ascending and descending colon now occurs. Disruption of any of these vital steps leads to the spectrum of malrotation encountered clinically. Alternatively, Kluth has proposed another model of intestinal rotation based on rat embryo studies.6 In this model, the rapid growth and subsequent duodenal lengthening forces the tip of the duodenojejunal loop to grow under the mesenteric root. Simultaneously,
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Ligament of Treitz
Ascending colon
Descending colon
Cecum
Figure 32-1. Normal intestinal anatomy results in fixation of the duodenojejunal junction in the left upper quadrant and the cecum in the right lower quadrant. This allows a wide breadth to the mesentery of the small bowel.
the distal midgut is also growing, forcing the cecum from a caudal to cranial position. In this hypothesis, cecal and colonic positioning is a passive process with final location of the midgut being based on a process of differential growth rather than active rotation. The most common forms of rotational disorders include nonrotation (Fig. 32-2), incomplete rotation (Fig. 32-3), and reversed rotation. Right and left mesocolic hernias can also occur. In nonrotation, there is failure of the normal intestinal 270-degree counterclockwise rotation around the superior mesenteric artery. Thus, the duodenojejunal limb lies in the right hemi-abdomen with the cecocolic limb in the left hemi-abdomen. Midgut volvulus due to a narrow mesenteric pedicle and extrinsic duodenal obstruction secondary to abnormally positioned cecal attachments are significant risks. In cases of incomplete rotation, normal rotation has been arrested at or near 180 degrees. The cecum will usually reside in the right upper abdomen. Obstructing peritoneal bands are present. With reversed rotation, an errant 90-degree clockwise rotation occurs, which leaves a tortuous transverse colon to the right of the superior mesenteric artery, passing through a retroduodenal tunnel dorsal to the artery and in the small bowel mesentery.7,8 The duodenum will assume an anterior position. Reverse rotation with volvulus may occur with obstruction of the transverse colon. Paraduodenal hernias are rare and result from failure of the right or left mesocolon to fuse to the posterior body wall. A potential space is created.
Figure 32-2. Illustration of nonrotation. The prearterial midgut (lightly shaded) is found on the right side of the abdomen, while the postarterial midgut (darkly shaded) remains on the left. Neither segment has undergone appropriate rotation. Volvulus is a risk.
Subsequently, the small intestine may become sequestered and potentially obstructed. A significant delay in diagnosis is often encountered.
PRESENTATION The incidence of malrotation has been estimated at 1 in 6000 live births. An increased incidence of 0.2% has been found in barium swallow studies,9 whereas autopsy studies estimate that the true incidence may be as high as 1% of the total population.10 Associated anomalies are common (Table 32-1).11 Rotational disorders are also known to coexist with heterotaxia but rarely with situs inversus.12 Intestinal malrotation occurs along a wide spectrum of anatomic variants and clinical presentations, including midgut volvulus and chronic duodenal obstruction. In-utero volvulus may lead to intestinal atresia. Classic malrotation with midgut volvulus is often discovered in a previously healthy term neonate. Up to 75% of patients present during the first month of life. Another 15% will present within the first year.13- 15 Volvulus, intestinal gangrene, and mortality have been noted regardless of the patient’s age or chronicity of symptoms.16 Bilious vomiting remains the cardinal sign of neonatal intestinal obstruction, and malrotation must be the presumed diagnosis until
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and mild abdominal discomfort are routinely reported. Partial volvulus leads to mesenteric venous and lymphatic obstruction and subsequently impairs nutrient absorption. The diagnosis becomes more challenging with the older child or teenager because the symptoms are often very vague and seemingly unrelated to the abdomen.17 The discordant incidence of malrotation between clinical cases and autopsy studies suggests that many patients are asymptomatic but “anatomically at risk” for midgut volvulus. Although most cases will present in the neonatal period or infancy, presentation in children or adults is not uncommon.18 Anomalies of intestinal rotation may be discovered incidentally in the teenager or adult during investigation for upper abdominal complaints. Yet, it is important to remember that these patients possess a narrow small bowel mesentery and thus remain susceptible to midgut volvulus.
DIAGNOSIS
Figure 32-3. Illustration of incomplete rotation. Both the prearterial (lightly shaded) and postarterial (darkly shaded) segments have undergone partial, yet not complete, rotation. Ladd’s bands are seen attaching the cecum to the right posterior abdominal wall. The duodenum becomes compressed and possibly obstructed. Volvulus is a risk.
Radiologic studies play a critical role in establishing a diagnosis of intestinal malrotation. Initial evaluation will usually begin with a plain anteroposterior abdominal flat plate combined with a lateral decubitus or upright view (Fig. 32-4). Variable, nonspecific findings are common. However, gastric and/or duodenal distention (“double bubble” sign) may be observed. Additionally, bowel wall thickening and edema may be present secondary to vascular compromise. A gasless
proven otherwise. Delays in diagnosis can be devastating. Other signs in the neonate include abdominal pain and distention. The inconsolable infant may rapidly deteriorate as metabolic acidosis quickly advances to hypovolemic shock. Late signs include abdominal wall erythema and hematemesis or melena from progressive mucosal ischemia. Laboratory investigation may reveal leukocytosis or leukopenia, hyperkalemia, and thrombocytopenia. Mesenteric vascular compromise rapidly leads to peritonitis, sepsis, shock, and death. Many other cases will present less dramatically. Failure to thrive, gastroesophageal reflux, early satiety,
Table 32-1 Incidence of Associated Anomalies
(by percent) with Malrotation
Intestinal atresia Imperforate anus Cardiac anomalies Duodenal web Meckel’s diverticulum Hernia Trisomy 21
5-26% 0-9% 7-13% 1-2% 1-4% 0-7% 3-10%
Rare: esophageal atresia, biliary atresia, mesenteric cyst, craniocynostosis, Hirschsprung’s disease, intestinal duplication.
Figure 32-4. Upright abdominal film in an infant demonstrating proximal small bowel dilatation. This infant had a midgut volvulus.
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MANAGEMENT
Figure 32-5. Lateral image on upper gastrointestinal series in an infant with malrotation and midgut volvulus showing the “corkscrew” appearance of the obstructed duodenum.
abdomen is particularly worrisome because the compromised bowel may be filled with fluid alone. Of particular importance is the presence of rectal gas in the newborn, which essentially excludes duodenal atresia (but not duodenal stenosis or web). If the diagnosis remains in doubt, an emergent upper gastrointestinal contrast study is needed to document the position of the ligament of Treitz. Delineation of the duodenojejunal junction remains the most important diagnostic tool with high sensitivity and is preferred over barium enema.19 The duodenum should be seen traveling across the spine to the left. Additionally, the lateral film will show the duodenum obtaining a retroperitoneal, posterior position. Abnormal findings include positioning of the duodenojejunal flexure to the right of the spine, obstruction of the duodenum, and the “coil spring,” “corkscrew,” or “beak” appearance of the obstructed proximal jejunum (Figs. 32-5 and 32-6). In some settings, color Doppler ultrasound imaging is favored and may reveal a dilated duodenum with inversion of the superior mesenteric artery and vein (the whirlpool sign) in cases of acute volvulus.20,21-23 Moreover, with ultrasonography, it is now possible to diagnose intestinal volvulus in utero. The patient with suspected or confirmed midgut volvulus should be aggressively resuscitated, given intravenous broad-spectrum antibiotics, and taken to the operating room for immediate exploration. Delaying surgery for confirmatory testing should be discouraged when the diagnosis is likely based on clinical grounds. Prompt diagnosis and exploration is paramount to limit the complications and mortality of massive bowel resection. Clinicians should counsel the family preoperatively, but an intraoperative discussion is also advisable in certain cases.
Management of children with radiographically proven symptomatic malrotation is relatively straightforward. A discussion of the open and laparoscopic techniques is presented later. Malrotation is an integral part of abdominal wall defects and congenital diaphragmatic hernia. Operative correction of these defects creates intra-abdominal adhesions. These patients are considered to be protected from volvulus. Therefore, Ladd’s procedure is not generally required. The dilemma arises when an abnormality is discovered on imaging, and the child is labeled as a “malrotation variant.” To exclude malrotation, the duodenojejunal flexure must be located to the left of the spine at the level of the duodenal bulb. Defined as the ligament of Treitz, this flexure may be in an equivocal position. Symptoms are generally mild and could easily be attributed to several diagnoses. Volvulus or internal hernia is usually not seen with malrotation variants. These children are usually referred, leaving the surgeon with the dilemma to decide whether the symptoms are truly related to the radiographic findings. Given the higher rate of persistence of symptoms after operation and an overall increase in postoperative complications in general, close observation or repeated contrast study has been suggested in these equivocal cases.24,25
Figure 32-6. Lateral image on upper gastrointestinal series in infant with malrotation and midgut volvulus showing the “beak” (arrow) appearance of the obstructed duodenum. Note that a small amount of contrast agent has progressed through the volvulus.
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Table 32-2 Six Key Elements in Operative
Correction of Malrotation
1. Entry into abdominal cavity and evisceration (open) 2. Counterclockwise detorsion of the bowel (acute cases) 3. Division of Ladd’s cecal bands 4. Broadening of the small intestine mesentery 5. Incidental appendectomy 6. Placement of small bowel along the right lateral gutter and colon along the left lateral ���������� ������������������ gutter
Open Surgical Technique There has been little change from Ladd’s original description of the operative technique for correction of malrotation with or without acute volvulus. Preoperative discussion with the family is crucial. The six essential/critical steps are summarized in Table 32-2. Prolonged resuscitation efforts are not warranted. Preincision broad-spectrum antibiotics should be administered in cases of suspected volvulus. The surgeon’s primary goal is to prevent the catastrophic loss of portions of the entire midgut. Entry into the abdomen through a right upper quadrant transverse approach is preferred, although a midline incision is also reasonable. In suspected cases of acute volvulus, time to detorsion is critical. Chylous ascites secondary to lymphatic obstruction and rupture of mesenteric lacteals is often encountered. When turbid fluid is seen, contamination should be suspected and peritoneal cultures taken. The bowel and mesentery should be eviscerated. One will commonly encounter two or three complete clockwise revolutions. The bowel will be often discolored and congested, although frankly gangrenous or perforated bowel is not uncommon. The bowel wall is fragile, and manipulation should be delicate. Care with counterclockwise detorsion is needed to prevent serosal or full-thickness injury (Fig. 32-7). The bowel may remain dusky. After detorsion, release of inflammatory mediators and lactic acid is common and may require aggressive fluid resuscitation and the temporary use of vascoactives. Once detorsion has been accomplished, ������������������� warm soaked �������������� lap pads are placed on the bowel, and the surgeon should patiently observe for reperfusion. Twenty or 30 minutes of intraoperative rewarming may be required. If perfusion remains in question, the surgeon has several options, including (1) assessment of the antimesenteric vascular integrity with the use of a Doppler probe and (2) intravenous administration of fluorescein with Wood’s lamp evaluation. After a period of observation, a limited segment of intestine may remain gangrenous and resection should proceed. However, when longer segments are of questionable viability, the principles of intestinal salvage and preservation should be remembered. Resection of clearly necrotic bowel should be performed while leaving bowel of uncertain perfusion in the abdomen (clip and drop) to be re-evaluated at a second-look operation 24 to 48 hours later. At the second exploration, recovery of questionable bowel or demarcation of
necrotic bowel requiring resection is usually obvious. Unfortunately, an occasional patient will have complete infarction of the midgut. Closure of the abdomen, without bowel resection and comfort care, may be considered after intraoperative family discussion. The development of intestinal and multiple-viscera transplantation makes this approach less clear. Assuming bowel viability has been confirmed, the breadth of the mesentery must be widened. This is accomplished through a series of maneuvers, including excision of cecal peritoneal bands traversing the duodenum (Ladd’s bands) and kocherization of the duodenum. The dissection then continues to the base of the superior mesenteric artery and vein by incising the anterior mesenteric leaflet. When properly opened, the mesentery is maximally broadened and the possibility of postoperative volvulus is reduced, although not completely eliminated. Most surgeons will complete the procedure with an appendectomy. Owing to the subsequent malposition of the cecum in the left upper quadrant, failure to remove the appendix could lead to diagnostic uncertainty and delay if appendicitis developed. Standard or inversion appendectomy is equally acceptable. Finally, as the surgeon prepares for closure, the duodenum and small intestine are positioned toward the right abdomen with the colon in the left abdomen. A final check to rule out mesenteric torsion is advisable. Suture fixation of the bowel to the lateral abdominal wall is not recommended.26,27 In patients without evidence of volvulus or obstruction, a nasogastric tube is not required. Bowel function generally returns in 1 to 5 days. However, older patients with chronic obstruction are likely to have a prolonged ileus, and thus nasogastric drainage and parenteral support should be considered. Antibiotics are not required. Feedings can be advanced per the surgeon’s discretion. Patients with extended or subtotal small bowel resection pose a special problem. Total parenteral nutrition is essential to sustain these patients until adaptation and compensatory growth of the residual bowel can occur.28 Small bowel or multiple-viscera transplantation should be considered. Postoperative intussusception has been noted in 3.1% of all patients who underwent a Ladd procedure, compared with 0.05% following other laparotomies.29 The incidence of recurrent volvulus is low. Finally, up to 10% of patients may develop an adhesive small bowel obstruction requiring laparotomy after the procedure.26,27,30
Laparoscopic Approach The laparoscopic treatment for intestinal rotation anomalies in neonates, infants, and children with or without midgut volvulus has been proposed by several authors since van der Zee’s original report in 1995.31 The previously published reports have been singleinstitution case reports or small case series. Clinical outcomes for the laparoscopic technique have been favorable. The patient is placed supine in the reversed Trendelenburg position, on a shortened operating room
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C
Figure 32-7. Open correction of malrotation. A and B, Initial appearance of the malrotated bowel during exploration. The surgeon first will perform counterclockwise detorsion of the midgut. C, Next, Ladd’s bands from the cecum to the right abdominal wall are divided. D, Last is the critical step of broadening the small bowel mesentery. An appendectomy is also performed.
A
B
table, if available. The surgeon will stand at the child’s feet with the assistant positioned to the surgeon’s left. Alternatively, the surgeon may stand at the patient’s right with the assistant and camera holder to the left. The stomach and bladder are decompressed. The child’s arms are tucked. A four-port technique provides adequate visualization with cannulas placed at the umbilicus, right and left mid abdomen, and subxiphoid region (for the liver retractor, if required). Gentle insufflation with carbon dioxide to a pressure of 8 to 12 mm Hg with flow at 2 to 5 L/min is generally well tolerated.31-33 Muscle relaxation will allow an optimal working space. Full abdominal exploration may reveal internal hernias, which are associated with malrotation. The surgeon’s first goal is to determine if malrotation is actually present and thus confirm preoperative imaging (Figs. 32-8 and 32-9). Tilting the table 30 degrees may help identify the ligament of Treitz and the ileocecal junction. Findings are variable but may include a high and medial cecal position and an elongated, tortuous duodenum. Although there are no specific guidelines established to predict whether a future volvulus will occur, a mesenteric
D
base extending more than half the diameter of the abdomen is generally sufficient to prevent volvulus.34 Owing to the necessity of rapid detorsion, the laparoscopic approach for acute volvulus is controversial. In these acute cases, a clockwise volvulus is easily recognized. The expeditious dissection may progress by identifying the second portion of the duodenum and excising restricting peritoneal bands. Next the surgeon may proceed with reduction of the volvulus (if present), mobilization of the duodenum and jejunum, and incision of the anterior mesenteric leaflet. The friable, ischemic bowel may be injured by the laparoscopic instruments. In older children with long-standing duodenal obstruction, the proximal bowel may be molded into a cocoon-like deformity (Fig. 32-10).33 Lastly, the appendix is brought out through the umbilicus for an extracorporeal appendectomy (Fig. 32-11). Alternatively, an intracorporeal appendectomy may be performed through the 5-mm ports using bipolar cautery and endoloops, or the surgeon may proceed with a standard stapled intracorporeal appendectomy if a 12-mm umbilical cannula has been placed. The ports are removed under direct visualization, and the
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A
B
Figure 32-8. An upper gastrointestinal study was performed in this infant who presented with vomiting. A and B, The radiologic interpretation was that the duodenum was entirely on the patient’s right side and the ligament of Treitz was at the level of pylorus. Also, the ligament of Treitz did not cross the midline. There was no evidence of obstruction. This patient underwent diagnostic laparoscopy and was found to have normal anatomy with correct positioning of the ligament of Treitz and the cecum (see Fig. 32-9).
incisions are closed in layers with absorbable suture. Postoperative management is similar to that for the open approach. Most children may begin clear liquids on the day of surgery. Discharge on day 1 or 2 is expected.33 Although each procedure will present its own challenges, several recommendations may expedite the procedure, decrease the conversion rate, and reduce surgeon frustration. For elective cases, decreasing stool burden with a gentle bowel preparation will improve visualization. Furthermore, it is important to position the working sites as far away as possible from the congenital bands, which increases the intraabdominal working space. Direct handling of the bowel increases the risk of serosal tears so gentle manipulation is important. The majority of the dissection may be accomplished by grasping the congenital bands or appendix. Since van der Zee’s initial report, other authors have described variations in technique and have published their positive results.35-38 Successful laparoscopic management of a 15-day-old with acute midgut volvulus has been described.39 The authors carefully reduced the acute volvulus, divided the Ladd’s bands, incised
A
the anterior mesentery, and performed an appendectomy. However, the majority of patients undergoing laparoscopic repair of intestinal malrotation have been elective cases without volvulus.36,37,40 Operative times have been reported to average 111 to 120 minutes.36,40 In one report, the time to a regular diet was 2 days (median) and resolution of symptoms was found in 5 of 7 patients at 15 months.36 In another series, 12 neonates and infants, weighing 3 to 7 kg, underwent a three-port laparoscopic Ladd’s procedure.35 Presentation included intermittent upper intestinal obstruction, and the diagnosis was eventually confirmed by contrast study. Three 3.5-mm ports were placed in the infraumbilical ring and in the right and left abdomen. Operative time was equivalent to published open results, ranging from 35 to 120 minutes (mean, 58 minutes). Feedings were started on postoperative day 1 or 2, and the patients were discharged at a mean of 2 days. All symptoms had resolved on postoperative evaluation. In a review of 21 adults undergoing both an open and laparoscopic Ladd procedure, comparative results were favorable for the laparoscopic group for resumption of oral intake (1.8 days vs. 2.7 days), shorter
B
Figure 32-9. At times, the upper gastrointestinal study can be equivocal for possible malrotation (see Fig. 32-8). In such patients, diagnostic laparoscopy is a useful technique to ascertain whether the patient actually has malrotation. A, In such patients, the position of the ligament of Treitz (arrow) to the patient’s left of midline is important. B, In addition, the location of the cecum in the right lower quadrant also helps verify that the patient does not have malrotation.
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Figure 32-10. In older children with long-standing partial obstruction or internal herniation, the Ladd bands may cause the bowel to form into a cocoon-like deformity. (From Moir CR: Laparoscopic Ladd procedure. In Holcomb GW III, Georgeson KE, Rothenberg SS [eds]: Atlas of Pediatric Laparoscopy and Thoracoscopy. Philadelphia, Elsevier, 2008, pp 55-60.)
hospitalization (4 days vs. 6.1 days), and decreased requirements for intravenous narcotics on postoperative day 1 (4.9 mg vs. 48.5 mg).41 Operative times, however, averaged 51 minutes longer for the laparoscopic patients (194 minutes vs. 143 minutes). Conversion to an open operation occurred in 25% of the patients undergoing a laparoscopic procedure. No patients required a second operation. One additional value of laparoscopy is found in cases of malrotation variants when the ligament
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of Treitz is in an equivocal position on preoperative imaging (see Fig. 32-8). Radiographic terms such as “wandering duodenum,” “low ligament of Treitz,” and “abnormal rotation” are frequently encountered in the radiologist’s vernacular. Such “soft” radiologic findings place the responsibility of excluding malrotation directly on the surgeon. In equivocal cases, laparoscopy may be used to determine the position and fixation of the cecum and the overall breadth of the mesenteric pedicle (see Fig. 32-9). Additionally, when performing open exploration based on these preoperative descriptives, a surgeon may find relatively normal rotation that is not suggestive of malrotation or prone to volvulus. The laparoscopic approach allows excellent visualization of the width and fixation of the mesentery and the presence of Ladd’s bands. Questionable cases are thus stratified regarding whether operative correction is required.42 If the mesentery is noted to be narrow, the patient will be prone to volvulus and requires operative correction. The procedure may continue with laparoscopic correction, or the surgeon may wish to convert to an open procedure at this point. The formation of intra-abdominal adhesions has generally been viewed as necessary to prevent postoperative volvulus. Through open exploration and direct manipulation of the bowel, adhesions are created. Concerns have been raised that adhesion formation may be limited with laparoscopy, as is seen in other laparoscopic procedures. Initial reports have not validated these concerns. Laparoscopic correction of malrotation is an accepted procedure but still remains a technical challenge. In patients with acute volvulus, the working space will be limited owing to bowel edema and chylous ascites. Although many cases can be accomplished with these minimally invasive techniques, conversion to an open procedure should be considered if significant progress has not been made after 60 minutes. As a collection, the available literature supports consideration of laparoscopy. Further prospective studies with large sample sizes, possible randomization, and long-term followup should be conducted to confirm the advantages and disadvantages of the laparoscopic approach.
Figure 32-11. When performing a laparoscopic Ladd procedure, an extracorporeal appendectomy eliminates the need for a large port for the endoscopic stapler. The appendix is grasped with one of the intracorporeal instruments and brought into view through the umbilicofascial defect, where it is grasped and exteriorized. (From Moir CR: Laparoscopic Ladd procedure. In Holcomb GW III, Georgeson KE, Rothenberg SS [eds]: Atlas of Pediatric Laparoscopy and Thoracoscopy. Philadelphia, Elsevier, 2008, pp 55-60.)
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THE OLDER PATIENT Malrotation is occasionally diagnosed in the teenager or adult, yet the symptoms are often vague, including vomiting, diarrhea, early satiety, bloating, dyspepsia, and ulcer disease.43-46 After a lengthy period of medical evaluation, some of these patients are labeled with functional or psychiatric disorders.10,44,45 The diagnosis may require multiple imaging modalities, including barium studies, computed tomography, magnetic resonance imaging, and angiography. Furthermore, preoperative imaging may also delineate vascular and/or hepatobiliary anatomic irregularities that are associated with rotational disorders.47 In the acute symptomatic patient, only emergent laparotomy can provide the correct diagnosis in a timely fashion. Given that adult surgeons may have little experience with this disorder, it is common for pediatric surgeons to be asked for intraoperative consultations. Outcomes in patients younger than 16 years old have been compared with those of patients older than 16.48 When compared with younger patients, the older patients experienced longer delays in diagnosis, endured a higher percentage of postoperative complications, and required a higher percentage of reoperation. No patients in the adult group were diagnosed correctly at the time of initial presentation.
The question arises whether an incidental discovery of malrotation in the older child or adult should be repaired at all. A candid discussion on the riskbenefit ratio with these older patients is important. The principle of “watchful waiting” has been suggested.49 Currently, there are no diagnostic modalities that can assess an individual’s future risk for midgut volvulus. Up to 20% of adult patients undergoing operative repair of malrotation will have an acute volvulus or bowel ischemia, both potentially life-threatening presentations.50 Furthermore, even in patients who are believed to be asymptomatic, preoperative symptoms attributable to malrotation have retrospectively been noted, and postoperative improvement has been seen.37,48,51 As noted by Ladd in 1932, malrotation is a “condition rare enough that it is likely to escape the mind, and it is common enough to be important.”4 This advice is especially true in older patients. The subtle presentation may lead to unnecessary or ineffective treatment. A high index of suspicion is required to prevent a delay in diagnosis, counsel patients effectively, and improve outcomes. Operative correction in the symptomatic and asymptomatic older patient is currently recommended.45,48,52,53
MALROTATION Danny C. Little, MD • Samuel D. Smith, MD
rotation of the human intestine requires N ormal transformation from a simple, straight alimentary tube into the mature fixed and folded configuration present at birth. Through precise embryologic events, the duodenojejunal junction becomes fixed in the left upper abdomen while the cecum is anchored in the right lower quadrant. The midgut, defined as the portion of the intestine supplied by the superior mesenteric artery, is thus suspended from a wide mesenteric base. In children with malrotation, the bowel is not fixed adequately and is thus held by a precariously narrow-based mesentery. Rotational anomalies create a spectrum of anatomic conditions with critical importance to the pediatric surgeon. Clinical disorders may arise when intestinal rotation either fails to occur or is incomplete. Rotational anomalies may be isolated or occur as an intrinsic component of gastroschisis, omphalocele, or congenital diaphragmatic hernia. Additionally, malrotation may present as an incidental, subtle finding discovered during the radiographic evaluation of another diagnosis or with septic shock from a catastrophic midgut volvulus. The earliest descriptions of intestinal development were from Mall in 1898 and later expanded upon by Frazer and Robbins in 1915.1,2 Eight years later, Dott translated these preliminary embryologic observations into problems encountered clinically.3 In his 1932 landmark surgical paper, Ladd described the evaluation and surgical treatment of malrotation.4 He described a relatively simple solution to a complicated problem. In his 1941 textbook entitled Abdominal Surgery of Infancy and Childhood, Ladd warned that unfamiliarity with this lesion would quickly lead to surgical confusion.5 Over 200 postmortem studies had been reported previous to Ladd’s paper, yet he was the first to emphasize the importance of placing the duodenum along the right abdominal wall, widening the mesenteric base, and moving the cecum to the left upper abdomen. With the exception of the laparoscopic approach, the original Ladd procedure has remained relatively unchanged. 416
EMBRYOLOGY The development of the midgut begins with the differentiation of the primitive intestinal tract into the foregut, midgut, and hindgut at the fourth week of gestation.6 The mature alimentary tract and all associated digestive organs are formed from this primitive tube. The most accepted model of midgut maturation involves four distinct stages: (1) herniation, (2) rotation, (3) retraction, and (4) fixation. Normal fixation of the duodenum and colon is illustrated in Figure 32-1. The intestinal loop can be divided into the cephalic (duodenojejunal) limb and the caudal (cecocolic) limb, which rotate separately but in parallel. The superior mesenteric artery serves as the fulcrum with the omphalomesenteric duct at the apex. Because of disproportional growth and elongation of the midgut during the fourth gestational week, the intestinal loop herniates into the extraembryonic coelom. Next, the bowel enters a critical period of rotation when the prearterial and postarterial limbs make three separate 90-degree turns, all in the counterclockwise direction around the superior mesenteric artery. The first 90degree rotation occurs outside the abdomen. The second 90-degree rotation commences during the return of the intestine into the abdominal cavity during the 10th gestational week. The duodenojejunal junction now passes posterior to the superior mesenteric artery. The last rotation occurs in the abdomen. The primitive intestine has thus completed a 270-degree counterclockwise rotation, allowing the duodenojejunal limb to be positioned to the left of the superior mesenteric artery while the cecocolic limb is on the right. Fixation of the ascending and descending colon now occurs. Disruption of any of these vital steps leads to the spectrum of malrotation encountered clinically. Alternatively, Kluth has proposed another model of intestinal rotation based on rat embryo studies.6 In this model, the rapid growth and subsequent duodenal lengthening forces the tip of the duodenojejunal loop to grow under the mesenteric root. Simultaneously,
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Ligament of Treitz
Ascending colon
Descending colon
Cecum
Figure 32-1. Normal intestinal anatomy results in fixation of the duodenojejunal junction in the left upper quadrant and the cecum in the right lower quadrant. This allows a wide breadth to the mesentery of the small bowel.
the distal midgut is also growing, forcing the cecum from a caudal to cranial position. In this hypothesis, cecal and colonic positioning is a passive process with final location of the midgut being based on a process of differential growth rather than active rotation. The most common forms of rotational disorders include nonrotation (Fig. 32-2), incomplete rotation (Fig. 32-3), and reversed rotation. Right and left mesocolic hernias can also occur. In nonrotation, there is failure of the normal intestinal 270-degree counterclockwise rotation around the superior mesenteric artery. Thus, the duodenojejunal limb lies in the right hemi-abdomen with the cecocolic limb in the left hemi-abdomen. Midgut volvulus due to a narrow mesenteric pedicle and extrinsic duodenal obstruction secondary to abnormally positioned cecal attachments are significant risks. In cases of incomplete rotation, normal rotation has been arrested at or near 180 degrees. The cecum will usually reside in the right upper abdomen. Obstructing peritoneal bands are present. With reversed rotation, an errant 90-degree clockwise rotation occurs, which leaves a tortuous transverse colon to the right of the superior mesenteric artery, passing through a retroduodenal tunnel dorsal to the artery and in the small bowel mesentery.7,8 The duodenum will assume an anterior position. Reverse rotation with volvulus may occur with obstruction of the transverse colon. Paraduodenal hernias are rare and result from failure of the right or left mesocolon to fuse to the posterior body wall. A potential space is created.
Figure 32-2. Illustration of nonrotation. The prearterial midgut (lightly shaded) is found on the right side of the abdomen, while the postarterial midgut (darkly shaded) remains on the left. Neither segment has undergone appropriate rotation. Volvulus is a risk.
Subsequently, the small intestine may become sequestered and potentially obstructed. A significant delay in diagnosis is often encountered.
PRESENTATION The incidence of malrotation has been estimated at 1 in 6000 live births. An increased incidence of 0.2% has been found in barium swallow studies,9 whereas autopsy studies estimate that the true incidence may be as high as 1% of the total population.10 Associated anomalies are common (Table 32-1).11 Rotational disorders are also known to coexist with heterotaxia but rarely with situs inversus.12 Intestinal malrotation occurs along a wide spectrum of anatomic variants and clinical presentations, including midgut volvulus and chronic duodenal obstruction. In-utero volvulus may lead to intestinal atresia. Classic malrotation with midgut volvulus is often discovered in a previously healthy term neonate. Up to 75% of patients present during the first month of life. Another 15% will present within the first year.13- 15 Volvulus, intestinal gangrene, and mortality have been noted regardless of the patient’s age or chronicity of symptoms.16 Bilious vomiting remains the cardinal sign of neonatal intestinal obstruction, and malrotation must be the presumed diagnosis until
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and mild abdominal discomfort are routinely reported. Partial volvulus leads to mesenteric venous and lymphatic obstruction and subsequently impairs nutrient absorption. The diagnosis becomes more challenging with the older child or teenager because the symptoms are often very vague and seemingly unrelated to the abdomen.17 The discordant incidence of malrotation between clinical cases and autopsy studies suggests that many patients are asymptomatic but “anatomically at risk” for midgut volvulus. Although most cases will present in the neonatal period or infancy, presentation in children or adults is not uncommon.18 Anomalies of intestinal rotation may be discovered incidentally in the teenager or adult during investigation for upper abdominal complaints. Yet, it is important to remember that these patients possess a narrow small bowel mesentery and thus remain susceptible to midgut volvulus.
DIAGNOSIS
Figure 32-3. Illustration of incomplete rotation. Both the prearterial (lightly shaded) and postarterial (darkly shaded) segments have undergone partial, yet not complete, rotation. Ladd’s bands are seen attaching the cecum to the right posterior abdominal wall. The duodenum becomes compressed and possibly obstructed. Volvulus is a risk.
Radiologic studies play a critical role in establishing a diagnosis of intestinal malrotation. Initial evaluation will usually begin with a plain anteroposterior abdominal flat plate combined with a lateral decubitus or upright view (Fig. 32-4). Variable, nonspecific findings are common. However, gastric and/or duodenal distention (“double bubble” sign) may be observed. Additionally, bowel wall thickening and edema may be present secondary to vascular compromise. A gasless
proven otherwise. Delays in diagnosis can be devastating. Other signs in the neonate include abdominal pain and distention. The inconsolable infant may rapidly deteriorate as metabolic acidosis quickly advances to hypovolemic shock. Late signs include abdominal wall erythema and hematemesis or melena from progressive mucosal ischemia. Laboratory investigation may reveal leukocytosis or leukopenia, hyperkalemia, and thrombocytopenia. Mesenteric vascular compromise rapidly leads to peritonitis, sepsis, shock, and death. Many other cases will present less dramatically. Failure to thrive, gastroesophageal reflux, early satiety,
Table 32-1 Incidence of Associated Anomalies
(by percent) with Malrotation
Intestinal atresia Imperforate anus Cardiac anomalies Duodenal web Meckel’s diverticulum Hernia Trisomy 21
5-26% 0-9% 7-13% 1-2% 1-4% 0-7% 3-10%
Rare: esophageal atresia, biliary atresia, mesenteric cyst, craniocynostosis, Hirschsprung’s disease, intestinal duplication.
Figure 32-4. Upright abdominal film in an infant demonstrating proximal small bowel dilatation. This infant had a midgut volvulus.
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Figure 32-5. Lateral image on upper gastrointestinal series in an infant with malrotation and midgut volvulus showing the “corkscrew” appearance of the obstructed duodenum.
abdomen is particularly worrisome because the compromised bowel may be filled with fluid alone. Of particular importance is the presence of rectal gas in the newborn, which essentially excludes duodenal atresia (but not duodenal stenosis or web). If the diagnosis remains in doubt, an emergent upper gastrointestinal contrast study is needed to document the position of the ligament of Treitz. Delineation of the duodenojejunal junction remains the most important diagnostic tool with high sensitivity and is preferred over barium enema.19 The duodenum should be seen traveling across the spine to the left. Additionally, the lateral film will show the duodenum obtaining a retroperitoneal, posterior position. Abnormal findings include positioning of the duodenojejunal flexure to the right of the spine, obstruction of the duodenum, and the “coil spring,” “corkscrew,” or “beak” appearance of the obstructed proximal jejunum (Figs. 32-5 and 32-6). In some settings, color Doppler ultrasound imaging is favored and may reveal a dilated duodenum with inversion of the superior mesenteric artery and vein (the whirlpool sign) in cases of acute volvulus.20,21-23 Moreover, with ultrasonography, it is now possible to diagnose intestinal volvulus in utero. The patient with suspected or confirmed midgut volvulus should be aggressively resuscitated, given intravenous broad-spectrum antibiotics, and taken to the operating room for immediate exploration. Delaying surgery for confirmatory testing should be discouraged when the diagnosis is likely based on clinical grounds. Prompt diagnosis and exploration is paramount to limit the complications and mortality of massive bowel resection. Clinicians should counsel the family preoperatively, but an intraoperative discussion is also advisable in certain cases.
Management of children with radiographically proven symptomatic malrotation is relatively straightforward. A discussion of the open and laparoscopic techniques is presented later. Malrotation is an integral part of abdominal wall defects and congenital diaphragmatic hernia. Operative correction of these defects creates intra-abdominal adhesions. These patients are considered to be protected from volvulus. Therefore, Ladd’s procedure is not generally required. The dilemma arises when an abnormality is discovered on imaging, and the child is labeled as a “malrotation variant.” To exclude malrotation, the duodenojejunal flexure must be located to the left of the spine at the level of the duodenal bulb. Defined as the ligament of Treitz, this flexure may be in an equivocal position. Symptoms are generally mild and could easily be attributed to several diagnoses. Volvulus or internal hernia is usually not seen with malrotation variants. These children are usually referred, leaving the surgeon with the dilemma to decide whether the symptoms are truly related to the radiographic findings. Given the higher rate of persistence of symptoms after operation and an overall increase in postoperative complications in general, close observation or repeated contrast study has been suggested in these equivocal cases.24,25
Figure 32-6. Lateral image on upper gastrointestinal series in infant with malrotation and midgut volvulus showing the “beak” (arrow) appearance of the obstructed duodenum. Note that a small amount of contrast agent has progressed through the volvulus.
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Table 32-2 Six Key Elements in Operative
Correction of Malrotation
1. Entry into abdominal cavity and evisceration (open) 2. Counterclockwise detorsion of the bowel (acute cases) 3. Division of Ladd’s cecal bands 4. Broadening of the small intestine mesentery 5. Incidental appendectomy 6. Placement of small bowel along the right lateral gutter and colon along the left lateral ���������� ������������������ gutter
Open Surgical Technique There has been little change from Ladd’s original description of the operative technique for correction of malrotation with or without acute volvulus. Preoperative discussion with the family is crucial. The six essential/critical steps are summarized in Table 32-2. Prolonged resuscitation efforts are not warranted. Preincision broad-spectrum antibiotics should be administered in cases of suspected volvulus. The surgeon’s primary goal is to prevent the catastrophic loss of portions of the entire midgut. Entry into the abdomen through a right upper quadrant transverse approach is preferred, although a midline incision is also reasonable. In suspected cases of acute volvulus, time to detorsion is critical. Chylous ascites secondary to lymphatic obstruction and rupture of mesenteric lacteals is often encountered. When turbid fluid is seen, contamination should be suspected and peritoneal cultures taken. The bowel and mesentery should be eviscerated. One will commonly encounter two or three complete clockwise revolutions. The bowel will be often discolored and congested, although frankly gangrenous or perforated bowel is not uncommon. The bowel wall is fragile, and manipulation should be delicate. Care with counterclockwise detorsion is needed to prevent serosal or full-thickness injury (Fig. 32-7). The bowel may remain dusky. After detorsion, release of inflammatory mediators and lactic acid is common and may require aggressive fluid resuscitation and the temporary use of vascoactives. Once detorsion has been accomplished, ������������������� warm soaked �������������� lap pads are placed on the bowel, and the surgeon should patiently observe for reperfusion. Twenty or 30 minutes of intraoperative rewarming may be required. If perfusion remains in question, the surgeon has several options, including (1) assessment of the antimesenteric vascular integrity with the use of a Doppler probe and (2) intravenous administration of fluorescein with Wood’s lamp evaluation. After a period of observation, a limited segment of intestine may remain gangrenous and resection should proceed. However, when longer segments are of questionable viability, the principles of intestinal salvage and preservation should be remembered. Resection of clearly necrotic bowel should be performed while leaving bowel of uncertain perfusion in the abdomen (clip and drop) to be re-evaluated at a second-look operation 24 to 48 hours later. At the second exploration, recovery of questionable bowel or demarcation of
necrotic bowel requiring resection is usually obvious. Unfortunately, an occasional patient will have complete infarction of the midgut. Closure of the abdomen, without bowel resection and comfort care, may be considered after intraoperative family discussion. The development of intestinal and multiple-viscera transplantation makes this approach less clear. Assuming bowel viability has been confirmed, the breadth of the mesentery must be widened. This is accomplished through a series of maneuvers, including excision of cecal peritoneal bands traversing the duodenum (Ladd’s bands) and kocherization of the duodenum. The dissection then continues to the base of the superior mesenteric artery and vein by incising the anterior mesenteric leaflet. When properly opened, the mesentery is maximally broadened and the possibility of postoperative volvulus is reduced, although not completely eliminated. Most surgeons will complete the procedure with an appendectomy. Owing to the subsequent malposition of the cecum in the left upper quadrant, failure to remove the appendix could lead to diagnostic uncertainty and delay if appendicitis developed. Standard or inversion appendectomy is equally acceptable. Finally, as the surgeon prepares for closure, the duodenum and small intestine are positioned toward the right abdomen with the colon in the left abdomen. A final check to rule out mesenteric torsion is advisable. Suture fixation of the bowel to the lateral abdominal wall is not recommended.26,27 In patients without evidence of volvulus or obstruction, a nasogastric tube is not required. Bowel function generally returns in 1 to 5 days. However, older patients with chronic obstruction are likely to have a prolonged ileus, and thus nasogastric drainage and parenteral support should be considered. Antibiotics are not required. Feedings can be advanced per the surgeon’s discretion. Patients with extended or subtotal small bowel resection pose a special problem. Total parenteral nutrition is essential to sustain these patients until adaptation and compensatory growth of the residual bowel can occur.28 Small bowel or multiple-viscera transplantation should be considered. Postoperative intussusception has been noted in 3.1% of all patients who underwent a Ladd procedure, compared with 0.05% following other laparotomies.29 The incidence of recurrent volvulus is low. Finally, up to 10% of patients may develop an adhesive small bowel obstruction requiring laparotomy after the procedure.26,27,30
Laparoscopic Approach The laparoscopic treatment for intestinal rotation anomalies in neonates, infants, and children with or without midgut volvulus has been proposed by several authors since van der Zee’s original report in 1995.31 The previously published reports have been singleinstitution case reports or small case series. Clinical outcomes for the laparoscopic technique have been favorable. The patient is placed supine in the reversed Trendelenburg position, on a shortened operating room
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C
Figure 32-7. Open correction of malrotation. A and B, Initial appearance of the malrotated bowel during exploration. The surgeon first will perform counterclockwise detorsion of the midgut. C, Next, Ladd’s bands from the cecum to the right abdominal wall are divided. D, Last is the critical step of broadening the small bowel mesentery. An appendectomy is also performed.
A
B
table, if available. The surgeon will stand at the child’s feet with the assistant positioned to the surgeon’s left. Alternatively, the surgeon may stand at the patient’s right with the assistant and camera holder to the left. The stomach and bladder are decompressed. The child’s arms are tucked. A four-port technique provides adequate visualization with cannulas placed at the umbilicus, right and left mid abdomen, and subxiphoid region (for the liver retractor, if required). Gentle insufflation with carbon dioxide to a pressure of 8 to 12 mm Hg with flow at 2 to 5 L/min is generally well tolerated.31-33 Muscle relaxation will allow an optimal working space. Full abdominal exploration may reveal internal hernias, which are associated with malrotation. The surgeon’s first goal is to determine if malrotation is actually present and thus confirm preoperative imaging (Figs. 32-8 and 32-9). Tilting the table 30 degrees may help identify the ligament of Treitz and the ileocecal junction. Findings are variable but may include a high and medial cecal position and an elongated, tortuous duodenum. Although there are no specific guidelines established to predict whether a future volvulus will occur, a mesenteric
D
base extending more than half the diameter of the abdomen is generally sufficient to prevent volvulus.34 Owing to the necessity of rapid detorsion, the laparoscopic approach for acute volvulus is controversial. In these acute cases, a clockwise volvulus is easily recognized. The expeditious dissection may progress by identifying the second portion of the duodenum and excising restricting peritoneal bands. Next the surgeon may proceed with reduction of the volvulus (if present), mobilization of the duodenum and jejunum, and incision of the anterior mesenteric leaflet. The friable, ischemic bowel may be injured by the laparoscopic instruments. In older children with long-standing duodenal obstruction, the proximal bowel may be molded into a cocoon-like deformity (Fig. 32-10).33 Lastly, the appendix is brought out through the umbilicus for an extracorporeal appendectomy (Fig. 32-11). Alternatively, an intracorporeal appendectomy may be performed through the 5-mm ports using bipolar cautery and endoloops, or the surgeon may proceed with a standard stapled intracorporeal appendectomy if a 12-mm umbilical cannula has been placed. The ports are removed under direct visualization, and the
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A
B
Figure 32-8. An upper gastrointestinal study was performed in this infant who presented with vomiting. A and B, The radiologic interpretation was that the duodenum was entirely on the patient’s right side and the ligament of Treitz was at the level of pylorus. Also, the ligament of Treitz did not cross the midline. There was no evidence of obstruction. This patient underwent diagnostic laparoscopy and was found to have normal anatomy with correct positioning of the ligament of Treitz and the cecum (see Fig. 32-9).
incisions are closed in layers with absorbable suture. Postoperative management is similar to that for the open approach. Most children may begin clear liquids on the day of surgery. Discharge on day 1 or 2 is expected.33 Although each procedure will present its own challenges, several recommendations may expedite the procedure, decrease the conversion rate, and reduce surgeon frustration. For elective cases, decreasing stool burden with a gentle bowel preparation will improve visualization. Furthermore, it is important to position the working sites as far away as possible from the congenital bands, which increases the intraabdominal working space. Direct handling of the bowel increases the risk of serosal tears so gentle manipulation is important. The majority of the dissection may be accomplished by grasping the congenital bands or appendix. Since van der Zee’s initial report, other authors have described variations in technique and have published their positive results.35-38 Successful laparoscopic management of a 15-day-old with acute midgut volvulus has been described.39 The authors carefully reduced the acute volvulus, divided the Ladd’s bands, incised
A
the anterior mesentery, and performed an appendectomy. However, the majority of patients undergoing laparoscopic repair of intestinal malrotation have been elective cases without volvulus.36,37,40 Operative times have been reported to average 111 to 120 minutes.36,40 In one report, the time to a regular diet was 2 days (median) and resolution of symptoms was found in 5 of 7 patients at 15 months.36 In another series, 12 neonates and infants, weighing 3 to 7 kg, underwent a three-port laparoscopic Ladd’s procedure.35 Presentation included intermittent upper intestinal obstruction, and the diagnosis was eventually confirmed by contrast study. Three 3.5-mm ports were placed in the infraumbilical ring and in the right and left abdomen. Operative time was equivalent to published open results, ranging from 35 to 120 minutes (mean, 58 minutes). Feedings were started on postoperative day 1 or 2, and the patients were discharged at a mean of 2 days. All symptoms had resolved on postoperative evaluation. In a review of 21 adults undergoing both an open and laparoscopic Ladd procedure, comparative results were favorable for the laparoscopic group for resumption of oral intake (1.8 days vs. 2.7 days), shorter
B
Figure 32-9. At times, the upper gastrointestinal study can be equivocal for possible malrotation (see Fig. 32-8). In such patients, diagnostic laparoscopy is a useful technique to ascertain whether the patient actually has malrotation. A, In such patients, the position of the ligament of Treitz (arrow) to the patient’s left of midline is important. B, In addition, the location of the cecum in the right lower quadrant also helps verify that the patient does not have malrotation.
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Figure 32-10. In older children with long-standing partial obstruction or internal herniation, the Ladd bands may cause the bowel to form into a cocoon-like deformity. (From Moir CR: Laparoscopic Ladd procedure. In Holcomb GW III, Georgeson KE, Rothenberg SS [eds]: Atlas of Pediatric Laparoscopy and Thoracoscopy. Philadelphia, Elsevier, 2008, pp 55-60.)
hospitalization (4 days vs. 6.1 days), and decreased requirements for intravenous narcotics on postoperative day 1 (4.9 mg vs. 48.5 mg).41 Operative times, however, averaged 51 minutes longer for the laparoscopic patients (194 minutes vs. 143 minutes). Conversion to an open operation occurred in 25% of the patients undergoing a laparoscopic procedure. No patients required a second operation. One additional value of laparoscopy is found in cases of malrotation variants when the ligament
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of Treitz is in an equivocal position on preoperative imaging (see Fig. 32-8). Radiographic terms such as “wandering duodenum,” “low ligament of Treitz,” and “abnormal rotation” are frequently encountered in the radiologist’s vernacular. Such “soft” radiologic findings place the responsibility of excluding malrotation directly on the surgeon. In equivocal cases, laparoscopy may be used to determine the position and fixation of the cecum and the overall breadth of the mesenteric pedicle (see Fig. 32-9). Additionally, when performing open exploration based on these preoperative descriptives, a surgeon may find relatively normal rotation that is not suggestive of malrotation or prone to volvulus. The laparoscopic approach allows excellent visualization of the width and fixation of the mesentery and the presence of Ladd’s bands. Questionable cases are thus stratified regarding whether operative correction is required.42 If the mesentery is noted to be narrow, the patient will be prone to volvulus and requires operative correction. The procedure may continue with laparoscopic correction, or the surgeon may wish to convert to an open procedure at this point. The formation of intra-abdominal adhesions has generally been viewed as necessary to prevent postoperative volvulus. Through open exploration and direct manipulation of the bowel, adhesions are created. Concerns have been raised that adhesion formation may be limited with laparoscopy, as is seen in other laparoscopic procedures. Initial reports have not validated these concerns. Laparoscopic correction of malrotation is an accepted procedure but still remains a technical challenge. In patients with acute volvulus, the working space will be limited owing to bowel edema and chylous ascites. Although many cases can be accomplished with these minimally invasive techniques, conversion to an open procedure should be considered if significant progress has not been made after 60 minutes. As a collection, the available literature supports consideration of laparoscopy. Further prospective studies with large sample sizes, possible randomization, and long-term followup should be conducted to confirm the advantages and disadvantages of the laparoscopic approach.
Figure 32-11. When performing a laparoscopic Ladd procedure, an extracorporeal appendectomy eliminates the need for a large port for the endoscopic stapler. The appendix is grasped with one of the intracorporeal instruments and brought into view through the umbilicofascial defect, where it is grasped and exteriorized. (From Moir CR: Laparoscopic Ladd procedure. In Holcomb GW III, Georgeson KE, Rothenberg SS [eds]: Atlas of Pediatric Laparoscopy and Thoracoscopy. Philadelphia, Elsevier, 2008, pp 55-60.)
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THE OLDER PATIENT Malrotation is occasionally diagnosed in the teenager or adult, yet the symptoms are often vague, including vomiting, diarrhea, early satiety, bloating, dyspepsia, and ulcer disease.43-46 After a lengthy period of medical evaluation, some of these patients are labeled with functional or psychiatric disorders.10,44,45 The diagnosis may require multiple imaging modalities, including barium studies, computed tomography, magnetic resonance imaging, and angiography. Furthermore, preoperative imaging may also delineate vascular and/or hepatobiliary anatomic irregularities that are associated with rotational disorders.47 In the acute symptomatic patient, only emergent laparotomy can provide the correct diagnosis in a timely fashion. Given that adult surgeons may have little experience with this disorder, it is common for pediatric surgeons to be asked for intraoperative consultations. Outcomes in patients younger than 16 years old have been compared with those of patients older than 16.48 When compared with younger patients, the older patients experienced longer delays in diagnosis, endured a higher percentage of postoperative complications, and required a higher percentage of reoperation. No patients in the adult group were diagnosed correctly at the time of initial presentation.
The question arises whether an incidental discovery of malrotation in the older child or adult should be repaired at all. A candid discussion on the riskbenefit ratio with these older patients is important. The principle of “watchful waiting” has been suggested.49 Currently, there are no diagnostic modalities that can assess an individual’s future risk for midgut volvulus. Up to 20% of adult patients undergoing operative repair of malrotation will have an acute volvulus or bowel ischemia, both potentially life-threatening presentations.50 Furthermore, even in patients who are believed to be asymptomatic, preoperative symptoms attributable to malrotation have retrospectively been noted, and postoperative improvement has been seen.37,48,51 As noted by Ladd in 1932, malrotation is a “condition rare enough that it is likely to escape the mind, and it is common enough to be important.”4 This advice is especially true in older patients. The subtle presentation may lead to unnecessary or ineffective treatment. A high index of suspicion is required to prevent a delay in diagnosis, counsel patients effectively, and improve outcomes. Operative correction in the symptomatic and asymptomatic older patient is currently recommended.45,48,52,53