Discussion
Our systematic review and subsequent meta-analysis, including a total of 1396 patients (703 LSG with OP), showed that laparoscopic sleeve gastrectomy with omentopexy is associated with significantly lower morbidity and lower gastric leak rate. Batman et al., in retrospective study with 1200 patients who underwent sleeve gastrectomy and omentopexy, suggest that it is a safe procedure with low complication rates (1.33% of all patients) [
17]. Only one of the included studies in our meta-analysis was a randomized control study (Pilone et al.).
The most severe complication after LSG is gastric leakage, which is associated with higher mortality rate [
18]. Our study shows that LSG with omentopexy is related with significantly lower rate of gastric leakage. Leaks occur when the intraluminal pressure is higher than the strength of the staple line [
19]. Sharma et al. give mathematical and anatomical theoretical explanations about increasing intragastric pressure after LSG. After standard LSG, the medial forces acting on sleeved stomach from ligaments are stable, but the lateral forces are lost as a result of detachment of the greater omentum. Omentopexy recreate stomach stabilization inside the abdomen preventing it from kinking and thus reducing the intragastric pressure [
14].
Few studies, carried out on a large group of patients, despite being excluded from our meta-analysis, confirm that omentopexy reduces the risk of gastric leakage. Sabri et al., in a retrospective cohort study on 2000 patients, shown that LSG with omentopexy can be effective in decreasing staple line bleeding, leakage, and hospital stay, although it prolongs the operative time [
20]. Lale et al., in study of 3942 LSGs divided into 3 groups ( group 1: no reinforcement, group 2: staple line reinforcement with fibrin glue, group 3: staple line reinforcement with omentopexy (SLR-O)), show that SLR-O during laparoscopic sleeve gastrectomy is a promising method for the prevention of postoperative leakage, bleeding, and twist complications with an increase in the duration of operation [
21]. However, the authors point out that taking into account the advantages of the introduced method, the extension of the duration of the procedure is acceptable.
In addition, only two selected studies (Pilone et al. and Hassan et al.) report length of procedure which longer in groups with omentopexy in both studies. There was no statistical analysis on the influence of omentopexy on the duration of procedure. However, despite the longer time with omentopexy, it may be worth considering if it will be proven that it reduces the number of leaks after standard LSG.
Analyzed studies did not provide any additional information on whether patients required any subsequent revision surgery. In our opinion, omentopexy may impede the procedures of revision bariatric surgery in the future.
Complication rate after laparoscopic sleeve gastrectomy is associated with higher body weight and Body Mass Index (BMI) [
22]. Referring to the results of our study, it is worth adding that despite the lower number of complications after LSG with omentopexy, one study showed different results. Ricardo et al., in a single-center study, in a group of 181 patients who underwent a laparoscopic sleeve gastrectomy (41% also underwent omentopexy), showed that omentopexy performed in patients who are super-obese had more complications than severely obese patients. Based on the data presented by Major et al. and Ricardo et al., qualification for LSG with omentopexy in super-obese patients should be more thoughtful due to a significantly higher number of complications [
22,
23].
The length of stay is a suitable indicator of the patient’s full mobilization, appropriate oral fluid tolerance, and whether there have been complications that may have contributed to delayed discharge. According to the ERAS Society guidelines, the patient after bariatric surgery may be discharged home when he meets the following criteria: tolerating an oral diet, consuming at least 1000 ml of fluids a day, no need for intravenous fluid therapy, postoperative pain is controlled with oral medications, the level of physical activity is similar to that before surgery, has constant contact with the treatment center, and there were no complications that would require postponement of hospitalization. Our study also shows that there is no significant difference in LOS between LSG with omentopexy and LSG without omentopexy. Heterogeneity between studies was significantly high (l2 92%). We observed that there is a noticeable difference in time range: Pilone et al. reported LOS in days (4.5 versus 5.8), but Hassan et al. reported in hours (32+/−9 versus 40+/−8) [
13,
16]. The difference may depend on the method of calculating the length of stay in the hospital and on well-developed outpatient care in accordance with the ERAS protocol [
24,
25]. In addition, an unbiased comparison of LOS between studies is difficult because it can be associated with local customs rather than fulfilling clear objective discharge criteria. Nevertheless, there is no information about the criteria for home discharge in both studies.
Our meta-analysis shows that omentopexy may decrease gastric leaks after LSG. However, omentopexy is not the first technique used to minimize this complication. Various preventive gastric leak techniques have been proposed, such as staple-line reinforcement (SLR). Another technique used for preventing staple-line leaks involves oversewing sutures. No consensus has been reached in the literature on the efficacy of SLR after sleeve gastrectomy in preventing leaks [
26]. For example Demeusy et al. in his analysis of total 198339 primary LSG and the relationship between various SLR techniques demonstrated that SLR is associated with decreased rates of bleeding and reoperations but does not affect leak rates [
27]. On the other hand, Gagner et al. in his systematic review of staple-line leaks following LSG demonstrated a significantly lower rate using APM (absorbable polymer membrane) staple-line reinforcement as compared to oversewing, use of sealants, BPS reinforcement, or no reinforcement [
28].
Two studies (Pilone et al. and Sharma et al.) mentioned about the effectiveness of SLR or fibrin glue suture on decreasing postoperative bleeding. Pilone et al. hypothesize that NBCA+MS sealant (Glubran®2) may decrease the risk of staple line bleeding and fixing of the omentum can enhance adhesive properties, reducing risk of leak. In Sharma’s study, the rate of bleeding did not reach statistical significance, in contrast to significantly lower leakage rates with omentopexy as compared with no omentopexy. According to the literature, there is also no consensus about the influence of fibrin glue on decreasing bleeding. In 2014, Musella et al., in randomized control trial, showed that the use of fibrin sealant in LSG significantly reduces postoperative bleeding [
29]. In turn, Mehmet Bayrak et al. suggest that the use of fibrin glue and over-sewing for staple line reinforcement during laparoscopic sleeve gastrectomy did not affect postoperative or perioperative hemorrhage and leakage [
30].
In addition to the above-mentioned conclusions, some researchers compare the effect on reducing postoperative gastroesophageal reflux (GER) and food intolerance. On the one hand, Filho et al. show that LSG with omentopexy improved the clinical score of GER and did not cause significant changes in the lower esophageal sphincter (LES) tone [
8]. On the other hand, Nasrati et al., in a retrospective cohort study in a group of 201 patients, show that omentopexy does not have a significant effect on reducing the incidence of de novo GERD after LSG after 1-year observation [
31]. Also Cheguevara et al., in a prospective randomized controlled trial in a group of 60 LSGs divided into two groups, show that omentopexy did not significantly decrease postoperative food intolerance or GI symptoms in morbidly obese patients undergoing LSG. Authors suggest that GERD impact scores were low at all the measured time points with or without an omentopexy and it may be related to the fact that all patients had administered a proton-pump inhibitor for at least 3 months [
32]. So far, no unequivocally positive effect on the reduction of symptoms in the form of gastroesophageal reflux has been found, but the described stabilization of sleeved gastric tube caused by omentopexy and its effect on facilitating food passage after resection requires further research and observation.
Our study has a lot of limitations. Two of four included studies are conference abstracts. In the included studies, the number of patients with gastric leakage was low. For this reason, to achieve sufficient patient numbers, larger multicenter studies are required.
Omentopexy is not a standardized procedure and the technique description varies between the studies
. Sharma et al., in their technique, placed 2–4 sutures at the site proximal to incisura and one suture at the most distal end of staple line [
14]. Pilone et al., after formation of the sleeve, applied a layer of the synthetic sealant on all rime sutures and cover it by an omentum flap [
13]. In Batman et al., omentopexy is performed by suturing the omentum back to the greater curvature with V-Loc sutures along the entire staple line [
17]. Furthermore, in two studies, there is a difference between the method of suture line reinforcement before performed omentopexy (Pilone et al. use a synthetic sealant and Sharma et al. use a buttress material (BSLR)). Despite that, in both cases, groups with omentopexy have lower numbers of gastric leakage
. The above examples show the difficulty in comparing procedures performed with different techniques. The lack of a clearly defined surgical technique affects the diversity of the results obtained.
In two studies, Pilone et al. and Sharma et al. used similar size of the boogie for sleeve calibration (42–48 Fr vs. 40–44 Fr). The potentially larger difference in the diameter of the boogie may affect the number of leaks. In literature, the size of the boogie, used for calibration, is also a subject of controversies, ranging between 32 and 60 Fr. Aurora et al., in a large systematic review (4888 patients), suggested that larger boogie size may decrease the leak rate [
33].
One study (Sharma et al.) includes information about dividing the team into surgeons doing LSG only, LSG with omentopexy only, or surgeons doing both procedures. In this particular case, all procedures were done by three surgeons (surgeon A performs LSG with omentopexy, while surgeons B and C do not perform omentopexy). There are no variables in the form of a different experience, skills, or a different position on the learning curve.
The effect of SLR after sleeve gastrectomy on bleeding or gastric leakage is still a controversial topic. Studies show either no effect or extremely different effects on bleeding and leak or no effect on leakage but decreased staple line bleeding. There is a need for more research to confirm the benefits of procedures potentially reducing gastric leakage or bleeding after LSG.
Because of limitations, included studies still do not provide decisive, high-grade results. In our opinion, more studies, especially RCTs, are required to fully assess this approach because the available data are of limited quality.
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