Reverse peristalsis is a rare complication of Roux-en-Y reconstruction seen with biliary and GI diversion procedures. Its presence may indicate improper length of the Roux limb, angulation, kink or narrowing of the jejunojejunostomy causing obstruction.
Reverse peristalsis can also be observed with Roux and Y misconstructions performed during gastric bypass surgery.1–3
These include the “Roux en O” construction, in which the biliary limb is connected to the gastric pouch or a reversed free alimentary segment, which may be seen more with revision surgery rather than primary construction. The incidence of these misconstructions is rare.
A small number of cases involving reverse peristalsis following Roux-en-Y gastric bypass without obvious misconstructions have been documented in the literature.4
Two additional reports have been published documenting a reverse peristaltic Roux limb following total gastrectomy and biliary enteric bypass after bile duct injury.5,6
When constructing the Roux limb, the jejunum is divided at varying lengths (typically 10cm to 30cm), depending on the type of procedure being performed. The length of the Roux limb itself is also variable usually in the range of 40cm to 60cm following gastrectomy and biliary bypass procedures with longer lengths of 60cm to 150cm utilized for gastric bypass surgery. Longer Roux limbs have been associated with greater weight loss and utilized in patients with higher BMIs.7
The inherent pacemaker cells of the small intestines are found in the duodenum. Ectopic pacemaker cells can be found throughout the jejunum and ileum. These ectopic pacemaker cells generate slower potentials that drive contractions in the Roux limb in the orad direction.8
Roux limbs of 35cm to 40cm have been shown to be effective at preventing reflux gastritis, ulceration, and delayed gastric emptying after Roux-en-Y construction. Roux limbs >40cm are associated with greater disruption of the normal antegrade contractile pattern.9
The optimal jejunal transection point and Roux limb length to prevent retrograde peristaltic activity have not been established.
Symptoms present in the immediate postoperative period are very nonspecific and can be indistinguishable from symptoms associated with other complications. This phenomenon also poses a challenge to identification by imaging, especially pertaining to the morbidly obese patient.1
Not only are there weight limitations posed by different radiologic modalities, but also technical modifications and adjustment to standard protocols need to be made for sufficient imaging to be obtained. Interpreting radiologists also need to be familiar with the altered anatomy and the associated complications of the procedure.
Initial imaging may be unremarkable. CT scan may show dilation of the Roux limb and raise the concern for a mechanical or possibly functional obstruction. Fluoroscopic imaging is a key component to diagnosis of motility disorders. The Roux limb may appear dilated, and initially contrast may pass unremarkably into the common channel. A larger amount of contrast may need to be administered to increase the luminal volume enough to trigger the retrograde peristaltic activity.1
Retrograde peristaltic activity is a transient phenomenon, with antegrade peristaltic activity restored once the Roux limb has decompressed itself. Generally, static fluoroscopic images appear unremarkable, so it is imperative that the radiologist spends sufficient time assessing the motility of the Roux limb in its entirety from the gastrojejunal to jejunojejunal anastomosis. Intestinal manometry has also been utilized to aid in the identification of reverse peristaltic activity following total gastrectomy; however, this is not readily available at most institutions.
The incidence of mechanical obstruction is approximately 2% to 3% following both open and laparoscopic gastric bypass.10
The level of obstruction is commonly at the jejunojejunal anastomosis leading to dilation of the Roux limb, biliopancreatic limb, or both.11
Because static imaging is unable to distinguish between functional and most causes of mechanical obstruction, forms of mechanical obstruction need to be ruled out. Causes of early mechanical obstruction include narrowing of the jejunojejunostomy anastomosis, angulation of the Roux limb, and obstruction of the Roux limb at the level of the transverse mesocolon.10–12
The presence of early obstruction is commonly attributed to errors in operative technique. The mean time to presentation of early obstruction is approximately 15 d. Common causes of late obstruction are internal hernias, adhesions, or herniation of small bowel through defects in the abdominal wall with the mean time interval for development being 7 mo.
Conservative management of presumed mechanical obstruction has been attempted with some success. However, because of the complexity and multitude of causes not easily distinguishable by radiologic imaging, operative exploration is often pursued. Direct operative visualization can also be utilized to diagnose functional obstruction, because reversed peristaltic waves can be directly observed as reported by Schrope et al.4
Surgical management of retrograde peristalsis requires correction of misconstructions, revision of the jejunojejunal anastomosis, or reversal of the gastric bypass. The Roux limb can be shortened or lengthened to reposition dominant ectopic pacemaker cells. Widening the jejunojejunostomy by making an enterotomy at the level of this anastomosis and firing a linear stapler through the afferent and efferent limbs may disrupt the area generating the disruptive migrating motor complexes and can correct any contributing mechanical component from narrowing or angulation. Another option is the creation of a proximal enteroenterostomy between the Roux limb and common channel, which acts as a separate outlet to bypass both functional and mechanical causes of obstruction. Construction of an “uncut” Roux-en-Y has been utilized following subtotal gastrectomy for adenocarcinoma, gastroparesis, peptic ulceration with gastric outlet obstruction, and bile reflux gastritis to avoid the effects of ectopic pacemaker cells generated by disruption of bowel continuity seen with Roux-en-Y construction.13
Its construction consists of a modified Billroth II gastrojejunostomy in which staples occlude the afferent jejunal lumen, while biliary and pancreatic secretions are diverted distally through a jejunojejunostomy. Creation of a “rho” shaped Roux-en-Y gastrojejunostomy after distal gastrectomy for gastric cancer has also been described to overcome the influence of ectopic pacemaker cells.14
The theory behind this construction is that delayed emptying will be prevented by allowing bidirectional flow generated by ectopic pacemaker cells in the rho-shaped intestine. These alternate constructions have not been utilized for weight loss surgery.