Antireflux Status Post Roux-en-Y anastomosis: An Experimental Study for Optimal Antireflux Technique.

BACKGROUND: Roux-en-Y hepaticojejunostomy has been a gold standard to establish biliary-enteric anastomosis for various surgical indications, but associated with variable incidences of cholangitis. This experimental study was conducted to report a modification in Roux-en-Y anastomosis for possible better alternative to provide antireflux procedure after Roux-en-Y biliary-enteric anastomosis with the aim to minimize the possibility of reflux and its consequences.
MATERIALS AND METHODS: For experimental study, the required fresh segment of Lamb's small intestine was procured. Three sets of Roux-en-Y anastomosis were created for each experiment. In set 1, there was simple Roux-en-Y anastomosis. In set 2, Roux-en-Y anastomosis along with 4-5 cm long spur between the hepatic and duodenal limbs was created. In set 3, in addition to Roux-en-Y with creation of spur, additional antireflux mechanism was created at the junction of upper two-third and lower one-third of the hepatic limb. Saline mixed contrast was infused by infusion pump to raise the intraluminal pressure to more than 10 cm of H2O. X-ray was taken at that time.
RESULTS: In set 1, all preparations demonstrated reflux of contrast in the hepatic limb. The set 2 also demonstrated the same findings of 100% reflux in the hepatic limb. In set 3, No reflux was observed in 8 (80%) preparations while remaining 2 (20%) preparations reveal partial reflux.
CONCLUSION: This experimental study suggests that the provision of spur and additional valve may be able to decrease the possibility of reflux in Roux-en-Y biliary-enteric anastomosis.

INTRODUCTION

For extrahepatic biliary tree pathologies, such as biliary atresia, choledochal cyst, and biliary stricture, biliary-enteric anastomosis like Roux-en-Y hepaticojejunostomy[1] has been a gold standard. It is believed to be associated with minimal incidence of cholangitis and thus preventing long-term biliary cirrhosis and other complications.[2]

Other alternatives of establishing biliary-enteric continuity in the form of jejunal interposition or hepaticoduodenostomy have not gained widespread acceptance because of very high incidence of ascending cholangitis, less subsequent decreased drainage, and long-term incidence of biliary cirrhosis.[3] Despite the widespread established safety of Roux-en-Y anastomosis, there have been reports of cholangitis,[4] leading to morbidity in the form of hospitalization.

Therefore, to prevent reflux of bile and pancreatic juice into the biliary tree, various techniques of antireflux procedure have been devised, namely, provision of long (90–100 cm) efferent loop of jejunum,[56] creation of spur between afferent and efferent limb of Roux-en-Y hepaticojejunostomy,[6] and making intussusception acting as a valve.[789]

Still, the aim of providing better antireflux mechanism after Roux-en-Y biliary-enteric anastomosis and eradicating the possibility of reflux and ascending cholangitis lingers on.

This experimental study was conducted to report a possible better alternative for providing antireflux procedure after Roux-en-Y biliary-enteric anastomosis for minimizing the possibility of reflux and its consequences.

MATERIALS AND METHODS

The study was conducted in experimental laboratory of the Department of Pediatric Surgery of the university hospital. Ethical clearance was obtained from the Institutional Ethics Committee. For experimental study, the required fresh segment of lamb's small intestine was procured from nearby slaughter house. The segment of intestine was cleaned with saline and over a bench; three sets of Roux-en-Y anastomosis were created for each experiment. Ten experiments were conducted over a period of 12 months.

In each set, duodenal limb of Roux-en-Y biliary-enteric anastomosis, kept 25 cm long, was connected proximally with 50 ml syringe filled with water-soluble contrast diluted with saline, along with infusion pump. Hepatic limb of Roux-en-Y biliary-enteric anastomosis was kept 40 cm long and was connected proximally with 50 ml syringe filled with water-soluble contrast diluted with saline along with infusion pump. The distal end of the jejunum was connected to the manometer [Figure 1]. Flow rate in infusion pump at duodenal end was set equal to physiological flow rate of duodenojejunal contents in jejunum. Similarly, flow rate in infusion pump at hepatic duct end was also set equal to physiological flow rate of bile in hepatic duct. An X-ray was taken in every set when manometer showed intraluminal pressure exceeding 10 cm of H2O.

Figure 1

Experimental setup to conduct the study. (A) Pressure infusion pump connected to 40 cm long segment of lamb intestine representing hepatic segment. (B) Pressure infusion pump connected to 25 cm long segment of lamb intestine representing duodenal segment. (C) Site for Roux-en-Y anastomosis. (D) Distal intestinal segment. (E) Manometer connected to distal segment of lamb intestine for pressure measurement in intestinal lumen

Set 1 - A simple Roux-en-Y anastomosis without any spur or antireflux mechanism was created [Figure 2A]

Figure 2

Method of creation of valve in hepatic segment

Set 2 - A Roux-en-Y anastomosis along with 4–5 cm long spur between the hepatic and duodenal limbs was created [Figure 2B]

Set 3 - In addition to Roux-en-Y with creation of spur, additional antireflux mechanism was created at the junction of upper two-third and lower one-third of hepatic limb by partial oblique transection of hepatic loop and the suturing of proximal and distal segment creating a flap valve and leaving 50% of lumen patent for unidirectional free flow of the diluted contrast [Figure 2C and D].

In each set, flow of the diluted contrast across the Roux-en-Y anastomosis was assessed by X-ray to demonstrate the reflux in hepatic limb of Roux-en-Y anastomosis.

The results were analyzed in terms of the amount of contrast reflux in the hepatic limb.

RESULTS

In set 1, all preparations demonstrated reflux of contrast in the hepatic limb [Figure 3a]. The set 2 also demonstrated the same findings of 100% reflux in the hepatic limb [Figure 3b]. In set 3, reflux of contrast in hepatic segment was absent in 8 (80%) preparations [Figure 3c] while in 2 (20%) preparations, partial reflux was observed [Figure 3d].

Figure 3

(a) Contrast X-ray in set 1 preparation showing contrast infused through duodenojejunal segment filling the hepatic and distal intestinal segment. (b) Contrast X-ray in set 2 preparation showing contrast infused through duodenojejunal segment filling the hepatic and distal intestinal segment despite creation of spur between duodenal and hepatic segment. (c) Contrast X-ray in set 3 preparation showing contrast infused through duodenojejunal segment filling the distal intestinal segment and proximal hepatic segment but almost nil refluxing beyond valve because of almost effective antireflux mechanism. (d) Contrast X-ray in set 3 preparation showing contrast infused through duodenojejunal segment filling the hepatic segment and distal segment despite creation of spur between duodenal and hepatic segment as well as valve in hepatic segment but filling in hepatic segment distal to valve is partial

DISCUSSION

In normal individual, after production of bile in liver, it flows through the right and left hepatic duct and common hepatic duct to be stored in the gallbladder. As per physiological need, gallbladder contracts and bile flows through common bile duct (CBD), through sphincter of Oddi into the duodenum. In response to contraction of smooth muscle of CBD, the sphincter of Oddi relaxes, thereby allowing the passage of bile. However, after this, it contracts again maintaining the high-pressure zone. In this manner, the CBD remain protected against the reflux of duodenal contents into the biliary tree.

In conditions such as choledochal cyst and biliary atresia, there is a need to make a Roux-en-Y biliary-enteric anastomosis. However, this bypasses the naturally available antireflux mechanism at sphincter of Oddi. Out of several options described in literature, Roux-en-Y biliary-enteric anastomosis is the gold standard for providing safe biliary drainage with minimum possibility of long-term anastomotic stricture and ascending cholangitis. However, some workers have reported that despite the provision of long loop, Roux-en-Y may be associated with troublesome cholangitis leading to morbidity, sepsis, and biliary cirrhosis.[10]

As per the law of physics dictating the flow of fluid in tube, it is natural that the flow of fluid will occur from high-pressure zone toward low-pressure zone. If the pressure remains similar, the flow of fluid also directed by the presence of valve in the passage and availability of free space that is fluid is flowing toward the free caliber rather the toward the valve.

In establishing the biliary-enteric anastomosis through Roux-en-Y, when bypassing the sphincter of Oddi, high-pressure zone is all together bypassed.

From the pressure flow study already published, we know that the intrahepatic biliary pressure is 20–30 mmHg.[11] It is also known that during peristalsis, the pressure rise in jejunum is 60–100 mmHg.[1213] Hence, in response to rise in pressure in the jejunum, there is always a possibility of reverse flow despite provision of long loop Roux-en-Y and spur.

In this study by transecting and creating a valve, we are providing double safety of prevention of reflux. By creating spur, we prevent the flow of fluid toward biliary tree, but, in addition to spur, partial transection has narrowed the lumen to 50% of its caliber. This, in turn, indirectly adds to rise in pressure by 16 times (Poiseuille's equation).[14]

Therefore, to some extent, it may compensate for the absence of valve within the safe limit, and this may possibly prevent the reflux. These findings necessitate the conducting of a long-term randomized study after obtaining institutional ethical clearance to establish the actual result of modified Roux-en-Y biliary-enteric anastomosis. There may be an apprehension that this experiment was conducted on a dead intestine, and results from previous studies are known vis-a-vis length of Roux loop and interposed antireflux mechanisms. However, we would like to say that this type of valve creation has not been evaluated previously; hence, this assumes significance. Despite this, we agree that this being an in vitro study needs long-term results when applied to patients.

There may be some technical difficulties because of the long suture line and creation of valve. This may lead to the possibility of procedure being difficult and precarious. Besides, there may be a possibility of blind loop syndrome, obstruction due to intussusception as it may act as lead point, and growth of such loop and spur over time, which may create other physiological problems. However, before analyzing it in a patient population, it remains a speculation.

The limitation of this study is it being an in vitro type, and the results may differ from that of an in vivo study. However, we feel that before any experimental confirmation, it is not justified to go for in vivo study.

CONCLUSION

This experimental study suggests that the provision of spur and additional valve may be able to decrease the possibility of reflux in Roux-en-Y biliary-enteric anastomosis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.