Bariatric surgery is the most effective treatment for obesity with clinically significant long-term weight loss along with amelioration or resolution of obesity-related comorbidities [1,2,3,4]. According to the American Society of Metabolic and Bariatric Surgery (ASMBS), approximately 280,000 operations were performed in the USA in 2022 for bariatric surgery [1]. The majority of these operations were the conventional vertical sleeve gastrectomy (cVSG), accounting for 57.4% of all bariatric operations. The Roux-en-Y gastric bypass (RYGB) is the second most common primary bariatric procedure, accounting for 22.2% of cases [5]. The reasons for the greater use of the cVSG include its procedural simplicity, i.e., no need for a gastrointestinal anastomosis, short operative time, ability to be performed as an outpatient procedure, durable long-term weight loss, and significant improvement of many obesity-related comorbidities. However, many studies have reported an unintended consequence of the cVSG which is worsening or new onset (de novo) gastroesophageal reflux disease (GERD) following the surgery. Depending upon the method of assessment and the follow-up duration, GERD incidence post-cVSG varied considerably with some studies reporting up to 68% [6,7,8,9,10,11]. A 2012 International Sleeve Gastrectomy Expert Panel reported an average GERD incidence of 31% after cVSG [9]. A 2020 meta-analysis estimated that 23% of patients developed de novo GERD after cVSG. [10] DuPree et al. in an analysis of 4832 patients undergoing cVSG found that 84% continued to have GERD symptoms postoperatively [7]. In the SM-BOSS trial conducted in Switzerland, patients with severe obesity were randomly assigned to cVSG (n = 107) or RYGB (n = 110) [12]. At 5-year follow-up, de novo GERD was reported by 18/57 (32%) and 6/56 (11%) in the cVSG and RYGB groups, respectively. Among the patients who had preoperative GERD, 32% in the cVSG group had worsening of symptoms compared to 6% in the RYGB group. In the SLEEVEPASS trial conducted in Finland, patients with severe obesity were randomized to either cVSG (n = 121) or RYGB (n = 119) [13]. GERD symptoms worsened at 10-year follow-up among 44/90 (49%) patients who had cVSG and 8/85 (9%) who had RYGB [13]. Using 24-h impedance, pH study, and manometry testing, Poggi et al. found that among VSG patients, the prevalence of pathological reflux increased from 47.2% preoperatively to 88.7% postoperatively; average DeMeester score increased from 16.7 (normal being < 14.7) to 42.9; LES pressure decreased from 12.3 to 8.9 mmHg, and the stimulated gastric pressure increased from 27.1 to 133.0 mmHg. [14] Although RYGB is an appropriate surgical alternative in the management of patients with obesity and preexisting pathologic reflux, this procedure is associated with a higher risk of complications including the risks for anastomotic marginal ulceration, dumping syndrome, bowel obstruction, and internal herniation, thus reducing its attractiveness as a primary bariatric operation [13, 14].

The GERD after cVSG was thought to be primarily related to the high-pressure, non-compliant system and technical issues associated with narrowing of the gastric incisura leading to a partial, distal gastric obstruction following sleeve gastrectomy [9, 15]. However, despite technical improvements in the construction of the sleeve over the years, GERD continues to plague this surgical procedure. We postulated that GERD development after sleeve gastrectomy is not related to individual skill level of the surgeon but rather due to the anatomic disruption of the antireflux barrier (ARB) as it relates with the specific technique of the cVSG operation, as it currently stands.

The cVSG, which reduces the gastric volume, did not consider the importance of avoiding the disruption of the ARB, which can lead to worsening of GERD. One of the native mechanisms protective against reflux is that the esophagus enters on the side of the stomach at an angle which results in the formation of a gastroesophageal valve mechanism. The latter can be seen on the retroflex view of the esophagogastric junction during endoscopic examination. The cVSG resects the entire gastric fundus and essentially creates a continuous tube with the esophagus entering directly into the stomach, thus eliminating the naturally-occurring gastroesophageal valve. Elimination of the gastroesophageal flap valve (GEFV) is one of the most important mechanisms for the increased risk of GERD after cVSG [16]. With the understanding that disruption of the ARB leads to the development of GERD, our trial proposes a surgical modification which is described as a flap valve preserving VSG (fvpVSG). The main technical modifications in the proposed fvpVSG include surgical principles that strengthen the ARB. Specifically, the technique for fvpVSG includes dissection of the esophageal hiatus with increasing the intra-abdominal esophageal length and repair of the diaphragmatic crura, both of which are not commonly performed in the cVSG unless there is a large hiatal hernia (Fig. 1). Additionally, the stapling technique for cVSG is altered, instead of gastric transection line going through the angle of His at the esophagogastric junction; it is performed 3 cm lateral to the angle of His thus preserving a small portion of the fundus/cardia (Figs. 2 and 3). This modification prevents disruption of the gastric sling fibers as shown in Fig. 3. Additionally, the preserved gastric fundus/cardia allows it to be wrapped around the distal esophagus (120–160° fundoplication) between 1 and 5 o' clock position, which we believe recreates the angle of His and preserves the GEFV (Figs. 4 and 5). This newly constructed gastroesophageal complex preserves the gastroesophageal valve that can act as a barrier to reflux. The latter can be visibly seen on endoscopic exam at follow-up (Fig. 6). The technical modifications described above align with the well-known principles of antireflux surgery (i.e., Nissen fundoplication) in the management of pathologic reflux. However, this technical innovation is not considered as a conventional fundoplication procedure combined with a sleeve gastrectomy as the preserved gastric fundus/cardia is too small to effectively perform any standard fundoplication procedures (i.e. Nissen, Rossetti-Nissen, Toupet, Dor, ect.). The goal for this innovation is more to reestablish the naturally-occurring flap valve that acts as an excellent antireflux barrier [16]. The proposed antireflux mechanism of the fvpVSG is related to the impact of gastric distention acting upon the esophageal high pressure zone [17]. In summary, the proposed fvpVSG is a technical innovation that incorporates the principles of antireflux surgery into cVSG to minimize GERD.

Laparoscopic esophageal hiatus dissection to achieve 3 cm intraabdominal esophageal length and closure of the diaphragmatic crus to strengthen the antireflux barrier

Gastric resection in the cVSG goes directly through the angle of His which disrupts the gastric sling fibers and eliminates the naturally-occurring gastroesophageal valve, defined as an anatomic valve composed of a segment of gastric fundus in direct apposition to the intraabdominal esophagus. In contrast, the fvpVSG strengthens the antireflux barrier by including (1) dissection of the hiatus to achieves 3 cm intraabdominal esophageal length, (2) preserving 3 cm of gastric fundus/cardia, and (3) performing partial wrap (120–160°) around the distal esophagus, thus preserving the gastroesophageal valve. The proposed antireflux mechanism of fvpVSG is related to the impact of gastric distention acting upon the esophago-gastric high pressure zone

Laparoscopic gastric stapling with preservation of 3 cm gastric fundus/cardia

Schematic drawing of the flap valve preserving sleeve gastrectomy

Laparoscopic preservation of the gastric fundus/cardia followed by reestablishing the angle of His and 120–160° partial wrap around the distal esophagus. It should be noted that the wrap occurs between 1-5 o'clock position with a goal to reestablish the naturally-occurring gastroesophageal valve

Endoscopic view of cVSG versus fvpVSG at 6 months follow-up. Endoscopic view of the fvpVSG demonstrates a visible gastroesophageal valve, whereas the cVSG shows a wide hiatal opening without a mechanical antireflux barrier to the esophagus