Impact of the Deep Neuromuscular Block on Oncologic Quality of Laparoscopic Surgery in Obese Gastric Cancer Patients: A Randomized Clinical Trial

Obesity can hinder laparoscopic procedures and impede oncological safety during laparoscopic cancer surgery. Deep neuromuscular block (NMB) reportedly improves laparoscopic surgical conditions, but its oncological benefits are unclear. We aimed to evaluate whether deep NMB improves the oncologic quality of laparoscopic cancer surgery in obese patients.We conducted a double-blinded, parallel-group, randomized, phase 3 trial at 9 institutions in Korea. Clinical stage I and II gastric cancer patients with a BMI at or above 25 kg m -2 were eligible and randomized 1:1 ratio to the deep or moderate NMB groups, with continuous infusion of rocuronium (0.5-1.0 and 0.1-0.5 mg kg -1 h -1, respectively). The primary endpoint was the number of retrieved lymph nodes (LNs). The secondary endpoints included the surgeon's surgical rating score (SRS) and interrupted events.Between August 2017 and July 2020, 196 patients were enrolled. Fifteen patients were excluded, and 181 patients were finally included in the study. There was no significant difference in the number of retrieved LNs between the deep (N = 88) and moderate NMB groups (N = 93; 44.6 ± 17.5 vs 41.5 ± 16.9, p = 0.239). However, deep NMB enabled retrieving more LNs in patients with a BMI at or above 28 kg/m2 than moderate NMB (49.2 ± 18.6 vs 39.2 ± 13.3, p = 0.026). Interrupted events during surgery were lower in the deep NMB group than in the moderate NMB group (21.6% vs 36.6%; p = 0.034). The SRS was not influenced by NMB depth.Deep NMB provides potential oncologic benefits by retrieving more LNs in patients with BMI at or above 28 kg/m2 during laparoscopic gastrectomy.