Sleeve surgery in Houston is the most commonly performed procedure for weight loss. Gastric sleeve surgery is, however, an excellent treatment option for type two diabetes without the long-term complications of gastric bypass. The underlying mechanism of diabetes resolution following gastric sleeve surgery is not fully elucidated. When properly performed, sleeve surgery, accelerates gastric emptying. The loss of the compliant gastric fundus with preservation of the antral pump lead to enhanced gastric emptying. The rapid food transit through the proximal gut changes the interaction between ingested food and intestinal tract leading to altered neuro-hormonal signals that seem to improve blood glucose level.
The short term evidence for gastric sleeve efficacy in type 2 diabetes resolution is robust. Many studies have demonstrated equal efficacy between gastric sleeve and bypass at 12 months after surgery. At 3 year follow up after surgery, the STAMPEDE trial showed that gastric bypass procedure is superior to sleeve surgery in terms of blood sugar control. Why are gastric sleeve surgery metabolic benefits less durable than those of gastric bypass when it comes to blood sugar control? Is it because of gastric fundus dilation and loss of the accelerated gastric emptying? Is there room for improving our current surgical technique to improve sleeve durability? Or is the sleeve doomed to fail in the long run?
I firmly believe that diabetes resolution following gastric sleeve surgery is highly dependent on how well the stomach is resected. A radical antrectomy, narrowed incisura and retained gastric fundus will greatly diminish the successful long term outcome of gastric sleeve surgery. “Contouring the sleeve” is not as simple as it sounds. I have learned over the past few years that complete gastric fundus resection requires complete gastro-esophageal junction mobilization and not simple visualization of the left crus. The fat pad must be carefully elevated and the angle of Hiss clearly visualized prior to gastric fundus resection. I always leave a small dog ear in that area to decrease the incidence of staple line leak. However, a retained posterior fundus will most likely dilate with time leading to GERD, weight regain and diabetes recurrence. Additionally, a narrowed incisura angularis creates a partial obstruction that leads to increased intra-gastric pressure and abnormal gastric peristalsis. Consequently, staple line leak, GERD and gastric fundus dilation incidence increases. A dilated gastric fundus in the setting of a narrow angularis results in decreased gastric emptying. If type 2 diabetes is a gastro-duodenal motility disorder, then one can easily see how gastric fundus dilation over time diminishes the effectiveness of gastric sleeve surgery in terms of blood sugar control.
It is very important to mention that gastric sleeve surgery “contouring” has nothing to do with bougie size. Indeed, bougie placement distorts the gastric angle at the incisura and prevents proper resection. For this reason, I navigate the incisura angularis without a bougie in place. Only after 2 or 3 staple firing that I place the bougie and continue the sleeve resection creating a straight gastric sleeve tube with no twisting or narrowing. When I perform the upper endoscopy intra-operatively I can visualize the antrum through the newly created angularis from the gastro-esophageal junction. If you have to maneuver the scope to pass through the angularis into the antrum you have narrowed the angularis and you have most likely increased the patient chances for long term failure.
From this perspective, one can appreciate the difference between gastric bypass and sleeve surgery from a technical point of view. There is little variation in gastric bypass anatomy that can affect its metabolic outcome. Gastric pouch size has no effect on extent of post-operative weight loss or diabetes resolution. Conversely, gastric fundus size in a sleeve gastrectomy can greatly alter the metabolic outcome especially in the long term. Long-term studies are needed to further understand the durability of gastric sleeve surgery in the treatment of type 2 diabetes. Particularly important, are studies that evaluate gastric emptying and gastric fundus size, several years after surgery, and their effect on blood sugar control.