LSG has emerged as a desired bariatric procedure as it avoids an intestinal bypass , with robust weight loss outcomes [2,3], and it does not have a steep learning curve . However, with its increased adoption and increased long-term data made available, studies reported an increased rate of postoperative GERD and EE after LSG [4, 12]. Despite knowing the pathophysiologic mechanisms involved in causing de novo GERD, including the increase in intraluminal pressure, removal of the fundus, presence of a hiatal hernia or disruption of the angle of His intraoperatively , there are reports that LSG may seem to improve pre-existing GERD as well . These relate to a decrease in intra-abdominal pressure from weight loss, loss of the stomach fundus and hence reduction in acid production, increased gastric emptying and reduction in volume due to the tubularisation of the stomach . As such, while the First International Consensus Conference recommended that higher degrees of EE and Barrett’s esophagus to be contraindications for LSG , there was no consensus on the type of surgery for patients with pre-existing GERD symptoms, as well as patients with an underlying hiatal hernia . Furthermore, the factors predisposing to GERD and EE after LSG were not well elucidated .
In this study, the prevalence of postoperative symptomatic GERD after LSG was 29.1%, with 26.0% of patients suffering from de novo GERD. This was comparable to that reported by Himpens et al, in their randomized controlled trial comparing LSG and gastric banding, where they reported a de novo GERD at 1-year of 21.8% . A total of 45.3% of patients suffered from postoperative EE, which was slightly lower than the 51.4% reported by Navarini et al, in their randomized controlled trial comparing LSG and Laparoscopic Roux-en-Y gastric bypass on its impact on postoperative GERD . The authors postulate that this could be due to the smaller sample size of patients who had undergone their esophagogastroduodenoscopy at their 1-year follow-up, and it is expected that the incidence of postoperative EE will increase with subsequent follow-up. Interestingly, the prevalence of preoperative symptomatic GERD in this study population is relatively low, at just 10.2%. The authors postulate that this could be due to a lower prevalence of GERD in Asia [20-22], as well as possible under-reporting of symptoms amongst patients with un-investigated GERD .
To our knowledge, this study was the first study to evaluate the Hill’s classification of the gastroesophageal junction on the likelihood of developing de novo or aggravating postoperative GERD or EE after LSG. In the univariate analysis, only the presence of a hiatal hernia and the Hill’s classification were significantly associated with postoperative symptomatic GERD and EE. Based on the multivariate analysis, only the preoperative Hill’s classification remained predictive for postoperative symptomatic GERD and EE (see Table 3 and 4). Also, the magnitude of the association appeared to correlate with a higher Hill’s grading. All patients with a Hill’s grade IV developed postoperative symptomatic GERD and EE. Patients with a Hill’s grade III had significantly higher odds of developing postoperative symptomatic GERD (OR 20.84, 95% CI: 3.98-109.13, p<0.001) and EE (OR 34.49, 95% CI: 1.08-1105.36, p=0.045) compared to patients with Hill’s grade I flap valve. For patients with Hill’s grade II, there were significantly more patients with postoperative symptomatic GERD (OR 7.13, 95% CI: 1.69-29.98, p=0.007), but not EE (OR 3.76, 95% CI: 0.21-66.30, p=0.366). This study thus demonstrated that the Hill’s classification system of the laxity of the gastroesophageal junction, even after adjusting for other preoperative factors, appeared to be better than preoperative GERD symptoms, preoperative presence of a hiatal hernia, or preoperative EE in predicting for postoperative symptomatic GERD and EE.
The Hill’s classification, first introduced by Hill et al in 1996, was derived from an observational study of 13 cadavers to determine the presence of an anti-reflux valve and hiatal hernia . In the absence of a hiatal hernia, the angle of His, defined as the acute angulation along the greater curve of the stomach where the esophagus enters the stomach , creates a flap valve mechanism [9, 25]. The laxity of this flap valve varies and can be objectively graded based on the Hill’s classification . This classification has been shown to be superior to the axial measurement of a hiatal hernia in the endoscopic assessment of the gastroesophageal junction and its association with GERD . This observation was similarly demonstrated in this study for patients who have undergone LSG as well. The authors believe that the predictive value of the Hill’s classification may be due to its ability to grade the mechanical laxity of the gastroesophageal junction. As previously demonstrated by Hill et al in their cadaveric studies , despite the absence of an active lower esophageal sphincter in a cadaver, a mechanical pressure gradient still existed in patients without a hiatal hernia, with lower Hill’s grade classifications. This mechanical gradient can be recreated in cadavers with a hiatal hernia by suturing the gastroesophageal junction to the preaortic fascia to recreate the angle of His and the gastroesophageal flap valve . Various mechanisms are thought to be responsible in maintaining the normal gastroesophageal junction, including the physiologic lower esophageal sphincter pressure , the diaphragmatic crura , length of the intra-abdominal esophagus  and the angle of His  with its associated gastroesophageal flap valve [9, 24, 25]. Our current study findings suggest that the integrity of the gastroesophageal flap valve and the laxity of the gastroesophageal junction graded by the Hill’s classification, may play a bigger role than previously thought, in determining the risk of GERD and EE after LSG.
Unlike measurement of the axial length of a hiatal hernia which is only useful to detect large hiatal hernias, the Hill’s classification system may potentially avoid missing patients with a lax gastroesophageal junction without a frank hiatal hernia. The use of axial length to grade a hiatal hernia can be subjective, with variations due to inspiration , as well as the physiologic shortening of the esophagus from either peristalsis, instrumentation, or distension . Thus, measurement of the axial length of a hiatal hernia is only useful to detect large sliding hiatal hernias. In this study, all patients diagnosed with a hiatal hernia on axial length had a type 1 sliding hiatal hernia, with a mean length of only 1.80cm (+ 0.79cm). Given that a separation of the squamocolumnar junction from the crural impression of 2cm or less may still be considered physiological , this might explain the discrepancy in the number of patients with a hiatal hernia diagnosed on axial length on endoscopy (n=17), in contrast to the number of patients with a Hill’s grade IV (n=2). This finding was not unexpected given the retrospective nature of the study as patients with a large hiatal hernia noted on axial length would have been counselled for a laparoscopic Roux-en-Y gastric bypass instead of a LSG. Hence, this may explain why the presence of a hiatal hernia does not appear to significantly impact postoperative symptomatic GERD and EE on the multivariate analysis. This explained why none of the patients in this study population with a preoperative hiatal hernia had undergone a concomitant hiatal hernia repair, as most of these hernias were small. However, given that both patients with Hill’s grade IV have a true anatomical hiatal hernia on axial length (both were 3cm in length), the study finding further strengthened the reproducibility and correlation between the Hill’s classification system with the axial length measurement system on clinically significant hiatus hernias. Furthermore, the study findings also support the Hill’s classification system as a predictive tool to stratify patients, who may not have a frank hiatal hernia, on their risk of postoperative symptomatic GERD and EE. In this context, the Hill’s classification in grading the laxity of the gastroesophageal junction and its impact on postoperative symptomatic GERD and EE may play a more important role than previously thought, as most patients undergoing LSG were likely those without any large hiatal hernias that can be detected on axial length.
It is hoped that these study findings can help in creating a standardised reporting system for preoperative esophagogastroduodenoscopy findings for patients undergoing LSG. On top of preoperative symptom evaluation of GERD, the axial length of any hiatal hernia and the presence of EE, the Hill’s classification of the gastroesophageal junction should also be documented. Based on the current study findings, at up to 1-year follow-up, less than one quarter and half of patients with Hill’s grade I or Hill’s grade II developed symptomatic GERD and EE after LSG respectively. In contrast, more than 50% of patients with Hill’s grade III had postoperative symptomatic GERD at up to 1-year follow-up, with a majority developing postoperative EE at 1-year follow-up. Lastly, all patients with Hill’s grade IV had symptomatic GERD and postoperative EE by 1-year. Thus, the authors believe that while LSG may be acceptable for patients with Hill’s grade I and II, patients with Hill’s grade III and IV might be better served with an alternative bariatric procedure instead, such as a laparoscopic Roux-en-Y gastric bypass, or a LSG with a hiatal hernia repair. In this study, patients with preoperative GERD, EE or hiatal hernia were offered laparoscopic Roux-en-Y gastric bypass, with LSG as an alternative. Patients included in this study had decided to proceed with LSG after an informed decision-making process.
Currently, opinions remain divided for patients with GERD symptoms undergoing bariatric surgery. Results from the First International Consensus Conference reported that slightly more than half of the surgeons surveyed will still recommend a LSG or a LSG with an anti-reflux procedure for patients with GERD symptoms . In the presence of an asymptomatic hiatal hernia, most surgeons will opt for a repair and closure of the hiatus during surgery . More studies are needed to determine the ideal surgical technique for such patients predisposed to GERD and EE after LSG. Initial results for concomitant LSG-fundoplication were associated with increased complication rates . The authors also eagerly await the results of the RELIEF trial, which investigated the role of LINXTM magnetic sphincter augmentation in patients with postoperative GERD after LSG, that has recently finished recruitment (ClinicaTrials.gov Identifer: NCT02429830).
This study has several limitations. Firstly, it is a single institution retrospective cohort study, hence prone to information and recall bias. Also, the follow-up period is short at only 1-year, and only a subgroup of patients (n=64) had undergone esophagogastroduodenoscopy at the end of 1-year. However, this subgroup of patients had similar outcomes as the entire cohort and hence was likely a representative sample for the analysis. In addition, GERD symptoms exist as a spectrum with varying degrees of severity, which may not be well represented in this study, which was reported as either present or absent. It is also unclear if the presence of a Los Angeles grade A esophagitis, which is itself subject to potential interobserver and intraobserver differences , would correlate with any clinically meaningful GERD. Also, the proportion of patients requiring preoperative proton pump inhibitors was unavailable. However, given that more than half of patients with postoperative symptomatic GERD had postoperative EE (51.7%), as well as the similar preoperative correlations between both GERD and EE outcomes, these outcome measures were likely clinically relevant. In addition, the presence of preoperative EE appeared to correlate with postoperative EE on the univariate analysis, though it did not reach statistical significance (p=0.067). The lack of such an association seen on the multivariate analysis might be related to the limited sample size in this study. Lastly, the study population is a heterogenous multi-ethnic Asian population, which may not be applicable to other regions. However, even with these limitations, the authors believe that the study findings are important, as it is the first study to document the importance of the laxity of the gastroesophageal junction, graded by the Hill’s classification system on predicting postoperative GERD and EE after LSG. Furthermore, the authors believe the study findings may potentially help shed light on the clinical importance of the gastroesophageal flap valve in maintaining the integrity of the gastroesophageal junction, both in physiologic and diseased states, as well as in cases where the stomach is tubularised such as after an LSG.