This research firstly compared iso- and anti- URYA after distal gastrectomy for gastric cancer. No differences were found between them in terms of short-term complications，nutritional status and quality of life one year after surgery. But endoscopic examination showed that anti-URYA group had more severe gastritis (P=0.036). More than 75% patients (79.2% for anti-URYA and 76.0% for iso-URYA) had an endoscopic review in the similar period after surgery, and the result could be convincing. So the anti-URYA might be closely related to reflux gastritis. But our findings could offer another explanation. The recanalization rate was significantly higher after the luminal occlusion by stapler (Table 4), and the luminal occlusion by stapler had a larger proportion in anti-URYA group than iso-URYA group (44.8% vs 11.5%, Table 2). So the anti-URYA group may have higher recanalization rate and further induce more severe gastritis. No significant differences in recanalization rates between iso- and anti- URYA group (P=0.554, Table 4) was probably because the proportion of patients who underwent contrast X-ray was insufficient (41.5% for anti-URYA group and 37.2% for iso-URYA group).
Little attention was paid to the orientation of peristalsis in previous studies [13-15]. In our institution, the orientation of peristalsis of URYA is mainly determined by surgeon’s personal preference. Surgeons who support anti-URYA argue that iso-URYA has a relatively limited and fixed space between gastrointestinal anastomosis and transverse mesentery and may further increase the incidence of internal hernia. Surgeons who support iso-URYA argue that anti-URYA transects the short gastric artery and may induce gastric stump ischemia. These arguments may exist but our study found no difference in short-term outcomes between two groups. So far, no RCTs focus on this problem. In this retrospective cohort study, we identified sufficient clinically essential covariates from among preoperative variables to maximize the comparability between iso- and anti- groups as far as possible. This methodology using actual clinical data with strict PSM may compensate for RCTs in the context of rapid developments in surgical treatment[16, 17].
The anastomotic bleeding was more common in iso-URYA comparing with anti- URYA (4.4% vs 2.2%, P=0.240), presumably because of the higher proportion of circular stapler use in iso-URYA group. Circular stapler has poor hemostatic effects by tissue squeezing and the following anastomotic reinforcement by suture may also increase anastomotic bleeding [18, 19]. An increased incidence of pancreatic fistula in anti-URYA group may be related to higher proportion of LAG (5.5% vs 2.7%, P=0.187). The possible reasons included intraoperative compression of the pancreas with long straight instruments, an inappropriate dissection plane along the pancreas, or thermal damage to the pancreas by energy devices in LAG.
URYA can divert biliary and pancreatic secretions away from the remnant stomach more efficiently by blocking the afferent loop and further prevent inflammation and even carcinogenesis of the remnant stomach and esophagus [3-5, 20, 21]. However, the recanalization of the jejunum after surgery may nullify this benefit. The luminal recanalization is caused by the failure of a fibrous healing process between the approximated mucosal surfaces [6, 22]. In this study, two methods, 0 # non-absorbable suture or no-knife linear cutter, were used to block the afferent loop. Only 2 out of 86 had recanalization for the former. 13 out of 58 had recanalization for the latter, of which 2 used 6-row linear stapler and 11 used 3-row linear stapler. So it seems that non-absorbable suture is more suitable for the luminal occlusion basing on the lower recanalization rate comparing with 3-row linear cutter and lower economic costs comparing with 6-row linear cutter. Our experience is that the ligation should be enough to block but not cut the small bowel. Too loose or too tight ligation both can induce early recanalization.
It cannot be denied that the present study had some important limitations. First, it was still retrospective in nature even after very strict PSM. There is no guarantee that all confounding factors were included in our analyses. RCTs will be necessary to assess the accuracy of this type of study. Second, this was a single center study. Therefore, we should be careful when extrapolating our results to all institutions. Third, this study could not survey postoperative symptoms severity. Assessment of subjective symptoms with a well-designed questionnaire might reveal the differences between two groups on early oral feeding or postprandial discomfort.
In conclusion, the iso-URYA and anti-URYA group present similar results in short term outcomes. The iso-URYA group had lower rate of severe gastritis comparing with anti-URYA group, and the reason lies in the higher proportion of ligation blocking afferent loop in iso-URYA group which leads to lower recanalization rate.