Our analysis revealed no difference in the 30-day incidence of SLL between the p-SLR and non-SLR group. However, the 30-day incidence of SLB was significantly lower in the p-SLR group. In addition, the operative time and LOS were significantly shorter in the p-SLR group. Otherwise, no differences were observed in intraoperative or postoperative outcomes.
Staple line leakage
Our main finding that SLL rates are similar in the p-SLR and non-SLR groups is largely confirmed in the literature.
The studies by Dawani et al. and Albanopoulos et al. used a similar method of p-SLR [10,11]. In the study by Dawani et al. three groups were compared: non-SLR, p-SLR with GORE® SEAMGUARD®, and reinforcement of the entire staple line with GORE® SEAMGUARD®. In contrast to our p-SLR group, Dawani et al. reinforced the staple line at both the fundus end and the pyloric end. They defined SLL as the presence of contrast material outside the gastric lumen during the postoperative gastrografin swallow test and could not demonstrate a difference in the occurrence of SLL. Albanopoulos et al. compared a p-SLR group with a group in which the entire staple line was reinforced with a continuous suture. In contrast to our study, where only the last staple cartridge was reinforced with GORE® SEAMGUARD®, Albanopoulos et al. reinforced on average the last 3 staple cartridges. SLL was defined in their study as presence of methylene blue in a routinely left drain on a swallow test on the second postoperative day, or leakage of contrast material on an upper gastrointestinal series or computed tomography scan. Three months postoperatively, no difference in the incidence of SLL was observed between the two groups.
Other working groups [13–17] have studied the effects of reinforcing the entire staple line with GORE® SEAMGUARD® and, with the exception of Durmush et al. [4], have been unable to demonstrate a reduction in the incidence of SLL. However, the comparison groups were heterogeneous. Thus, in some studies, reinforcement of the staple line was omitted, whereas in others, such as the study by Durmush et al, reinforcement of the staple line was performed with oversewing or fibrin glue.
We decided to use SLR only on the most proximal portion of the staple line, since SLL occur most frequently in this part [6]. Reinforcing the entire staple line with GORE® SEAMGUARD® would theoretically only increase the cost without further preventing the risk of SLL. However, the results of our analysis do not support this strategy of p-SLR.
If we look in detail at the SLL that occurred in our patients and divide them into proximal and distal SLL, we see that 3 proximal and 4 distal SLL occurred in the p-SLR group. One SLL in the p-SLR group and the 2 SLL in the non-SLR group cannot be classified because, despite computed tomographic evidence of an abscess, the site of the SLL could not be clearly identified during revisional surgery.
The most appropriate method to find out whether our strategy of p-SLR has an impact on the reduction of SLL would be to compare the difference in the occurrence of proximal SLL between the two groups. Unfortunately, because classification into proximal or distal SLL was not possible in the non-SLR group, we could not perform this subgroup analysis. We can only speculate whether such an analysis would have revealed a difference in the occurrence of SLL.
Staple line bleeding
Our analysis showed a significantly lower incidence of SLB in the p-SLR group, which contradicts the existing literature.
Dawani et al. and Albanopoulos et al., whose surgical technique of p-SLR is most similar to ours, found no effect of p-SLR with GORE® SEAMGUARD® on the occurrence of SLB. However, Dawani et al. only studied intraoperative bleeding from the staple line and not the incidence of postoperative SLB. Of the other groups [4,13,15–17] that performed reinforcement of the entire staple line with GORE® SEAMGUARD®, only Gayrel et al. demonstrated a significantly lower rate of SLB compared to a non-SLR group. However, Gayrel et al. focused on a high-risk population in their study, and this finding may represent a type of selection bias.
Yong et al. [18] reported that direct bleeding from the staple line and bleeding from transected branches of the right gastroepiploic artery and short gastric arteries are the main causes of SLB. Based on the results of the study by Chakravartty et al. [19], who reported that most intraoperative bleeding occurs in the middle part of the staple line (second to fourth staple firing), it can be concluded that the most proximal part of the staple line is not the most common site for the manifestation of SLB, unlike SLL.
The non-SLR group represents our early experience with SG in our bariatric center, which is also reflected in the significantly shorter operative time in the p-SLR group, as described below. Therefore, we interpret the lower incidence of SLB in the p-SLR group as a result of the surgeons' learning curve and increasing experience and better standardization in perioperative care in this patient cohort.
Other intra- and postoperative findings
We observed a significantly shorter operative time and LOS in the p-SLR group. As intraoperative complications were similar in both groups, we interpret the shorter operative time in the p-SLR group to be related to the surgeons' learning curve and better standardization of the operation. Otherwise, it is difficult to justify a relevant effect of SLR on operative time.
Similarly, the shorter LOS cannot be attributed to a lower rate of postoperative complications, as their frequency (i.e., complications with a grade ≥ 3 according to Dindo-Clavien [20]) was similar in both groups. Therefore, the shorter LOS in the p-SLR group should be attributed to the surgeons' experience and safety acquired over the years rather than to SLR.
Limitations
This was a retrospective analysis in which data were retrieved from medical records. The lack of randomization was compensated for by a comprehensive PSM analysis. Other limitations include small sample size and lack of long-term follow-up data.