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Intraoperative leak tests correlated with increase in staple line leakage but a lower rate of postoperative bleeding

Intraoperative leak test (IOLT) is correlated with an increase in staple line leakage (SLL) when included as a part of a sleeve gastrectomy (SG), but it is also associated with a lower rate of postoperative bleeding and should be considered when performing a SG in the situation of suspected postoperative bleeding, according to a meta-analysis by researchers from China and the US.


Figure: 1a Evaluation of perfusion of the staple line of the stomach by using the indocyanine green test. 1b Intraoperative picture of the staple line of the stomach

The authors noted that a previous international SG expert panel failed to reach a consensus (48% consensus) about whether routine IOLTs should be performed. In addition, it has also been reported in the literature that the leak rate was higher in patients with air insufflation or methylene blue versus without and IOLT could cause iatrogenic injury due to excessive dilation of the remaining gastric pouch.


Therefore, the authors carried out a meta-analysis to compare postoperative staple line leakage, postoperative bleeding, 30 days mortality rates and 30 days readmission rates of IOLT with no intraoperative leak test (NIOLT) for SG. They identified six studies (published between 2016 and 2022) that met the inclusion criteria with 324,264 assigned to the IOLT group and 145,324 to the NIOLT group. All studies performed intraoperative endoscopic or non-endoscopic methods (naso/orogastric tube insertion), which used air injection or used methylene blue to test for leakage. The researchers noted that there was a low statistical heterogeneity between the six studies (I²=0%, o=0.56), therefore they used a fixed effect model for the meta-analysis.


Outcomes

The analysis reported that the SLL rate was 0.38% (1221/324,264) in the IOLT group and 0.31% (453/145,324) in the NIOLT group. The meta-analysis showed that postoperative staple line leakage was lower in the NIOLT group than the IOLT group (OR=1.27; 95% CI: 1.14–1.42, p=0.000).


After performing a subgroup analysis, two included studies used the methylene blue test was adopted in the IOLT group. The postoperative staple line leakage rate was 0.25% (356/142 673) in the IOLT group, and 0.23% (98/42 317) in the NIOLT group. There was no statistically significant differences in the IOLT group and in the NIOLT group (OR=1.09; 95% CI: 0.87–1.36, p=0.458). In three studies were air insufflation or methylene blue dye was used in the IOLT group, the postoperative staple line leakage rate was 0.44% (259/59 110) in the IOLT group and 0.34% (198/57 534) in the NIOLT group. They reported that the postoperative staple line leakage was lower in the NIOLT group than that in the IOLT group (OR=1.22; 95% CI: 1.02–1.48, p=0.033).


Three studies (279,216 patients) that reported postoperative bleeding, the rate was 0.59% (1059/178 112) in the IOLT group and 0.76% (766/101 104) in the NIOLT group. The meta-analysis showed that postoperative bleeding was lower in the IOLT group than that in the NIOLT group (OR=0.79; 95% CI: 0.72–0.87, p=0.000).


Two of the included studies reported that the 30-day mortality rate of patients was 0.1% (103/143 776) in the IOLT group and 0.1% (33/42 312) in the NIOLT group. Due to the moderate heterogeneity (I2=66%, p=0.08), a random-effect model was used for meta-analysis, which found no statistically significant differences in the 30-day mortality rates between the two groups (OR=0.36; 95% CI: 0.03–5.09, p=0.45).


In total, 1.78% (5700/320,333) patients had 30 days readmission rates in the IOLT group and 2.28% (1,794/142 996) in the NIOLT group. There was no significant difference in the 30 days readmission rates between the IOLT group and the NIOLT group (OR=0.98; 95% CI: 0.94–1.02, p=0.33).


The authors hypothesise that one possible explanation for NIOLT having a lower rate of postoperative staple line leakage compared to IOLT, is that postoperative leakage may occur due to a fault in the testing mechanism. They explain that the calibration tube is already present in the stomach before stapling. When the test is about to be conducted, the calibration tube is gradually drawn up to the upper stomach, and then the test is performed. Therefore, there may be no need to insert it, thus reducing the risk of staple line injury.


“Prospective studies proposing a systematic way of performing IOLT are still needed,” the authors concluded. “Further studies, perhaps incorporating manometric factors into IOLT, should be considered.”


The findings were reported in the paper, ‘Comparison of the postoperative outcome with and without intraoperative leak testing for sleeve gastrectomy: a systematic review and meta-analysis of 469 588 cases’, published in the International Journal of Surgery.


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