Gastric cancer is a major health problem, as it is the second leading cause of cancer death and the fourth most common cancer worldwide23. Surgery is a major curative strategy for gastric cancer23. A PD is created after gastrectomy with B-2 or R-Y reconstruction. However, there has been no consensus yet on how to deal with it.
The study showed that the rates of SBO and SIH were significantly decreased after closure of PD. The rate of IH was not significantly decreased after closure of PD, probably reflecting the very low number of IHs. In the descriptive analysis, the rate of IH was much lower in the closure group (1/385, 0.3%) than the non-closure group (9/828, 1.1%). The analysis of the risk factors for IH and SIH additionally validated these findings. Our results were consistent with those of previous studies9, 20, 24.
Theoretically, if mesenteric defects are completely closed, no IH can occur through mesenteric defects. However, similar to a previous study8, after we closed the PDs, one case of IH occurred. We found that the IH patient underwent gastrectomy in the first week when we started to close the PD, and there have been no IH patients in closure group since then. Both surgeons participating in the study were very well experienced with gastrectomy and far beyond their learning curve for this operation, but this was not necessarily the case for PD closure. Therefore, the reason for this may be incomplete closure of the PD during primary surgery25.Another explanation is that defects may open out after the loss of mesenteric fat, leading to the formation of IH26. Therefore, although closure of all mesenteric defects cannot completely prevent IH, current studies have shown that it may decrease the rate.
The overall rate of IH was 0.8% in our study, and it ranged from 0.19–5% in previous studies1, 7, 8, 20. The rate of IH varied greatly among different literatures. These differences may be caused by different inclusion groups, diagnostic criteria, follow-up periods, laparoscopy proportions, and mesenteric defect closures1. The rate of IH in the study was lower than that in most studies. The possible reason is that we routinely closed the JMD in all patients, and no IH was found in the JMD in this study; however, most authors left it open before they changed their technique to close all mesenteric defects. In a study conducted by Miyagaki et al8, all gastrectomies, regardless of reconstruction method or gastrectomy type, were invested, including patients with little possibility of IH such as those who underwent esophagogastrostomy and Billroth-1 reconstruction. The 3-year incidence rate of IH in their study was 0.19%, which was the lowest in literature.
Laparoscopic surgery was considered a risk factor for IH in most previous studies1, 7, 8, 20, 27. The possible reason was fewer adhesions1, 8. However, similar to a previous study9, it was not a risk factor in the present study. The possible explanation was that we adopted laparoscopy-assisted surgery in most cases. However, most authors mainly adopted total laparoscopic surgery in previous studies. Laparoscopy-assisted surgery may result in more adhesions than total laparoscopic surgery.
In previous studies on the effect of closure of mesenteric defects in gastrectomy for gastric cancer, IH was defined as the only endpoint, but if SBO and SIH were not included, the effect of mesenteric defects closure may be overlooked. Due to its rare incidence and nonspecific symptoms, it is difficult to diagnose IH preoperatively. CT scans have become the main work-up to diagnose IH before surgery11 and some authors held the idea that “whirl sign” on CT scans was the most predictive sign of IH (sensitivity 78-100%, specificity 80-90%)3, 12, 18, 19 . Kang et al20 even used the “whirl sign” as a diagnostic criterion for IH in their study. In the present study, 2 patients were considered to have SIH according to our criteria before surgery, and they were finally confirmed to have IH by surgical exploration. Another 20 non-operatively treated SBO patients also showed a “whirl sign” on CT examinations. The reason why they were managed nonoperatively was that they had no signs of bowel necrosis, and they were reluctant to receive surgery, or surgery was not physically allowed. There is a high possibility that in some of these patients with SBO, it was caused by IH, although this was not confirmed by surgical exploration. Therefore, we defined these patients as having SIH in this study. Additionally, the work-up for IH was mainly performed with CT scan, and it is possible that these false negative CT patients were not diagnosed with IH; however, SBO is not easily missed with CT scans28. It is also possible that some patients who underwent operation for SBO actually suffered from IH, and they were not identified during the procedure29. Therefore, considering the above factors, we included both SIH and SBO as endpoints in this study.
SBO is a well-described complication after abdominal surgery and adhesion is considered as the cause of almost 75% SBO, other etiologies including IH, inguinal hernia, incisional hernia, and obstructive tumor etc30. The rate of SBO after gastrectomy for gastric cancer ranged from 11.7 to 38.5% in previous studies31, 32.The rate of SBO reported in this study was 12.4%, which was similar to previous studies. The rate of SBO may be influenced by different diagnostic criteria, follow-up periods, and proportions of laparoscopy. In our study, SBO was defined as an episode of intestinal obstruction caused by IH, SIH and adhesions. And we found that there was no significant difference in the rate of adhesive SBO between the two groups.
There is concern that closure of the mesenteric defects may be associated with a higher rate of postoperative complications such as mesenteric hematomas and bleeding. However, in our study, there was no difference in the rate of complications within 30 days between non-closure and closure groups. It showed that closure of PD did not increase early postoperative complications.
The strengths of the study were that it followed a standardized surgical protocol and two distinct groups for comparison. Both surgeons participating in the study were well and equally experienced in gastrectomy for gastric cancer. The limitations of the study include that it was a retrospective study conducted in a single center. The number of IHs in our study was too small for analysis, and we included SIH to investigated the risk factors. Another potential limitation of the study was that the follow-up duration was different between the two groups. However, the rate of IH seems to be highest within 1-2 years after operation33-35,corresponding to the time of the largest weight loss3. And in the non-closure group, 7 out of 9 IH cases (78%) presented within the first 16 months after gastrectomy. Considering that 85% of patients in the closure group were followed for more than 16 months, we would not expect a large number of additional IHs in this group. A multicenter prospective study is required to evaluate patients with closure of all mesenteric defects during gastrectomy, including postoperative complications and quality of life.
In conclusion, closure of PD is recommended after gastrectomy for gastric cancer, as we noticed a significantly lower rate of SIH and SBO and a tendency for lower rate of IH, while the procedure did not significantly increase postoperative complications.