Effect of Patient Body Mass Index on Laparoscopic Surgical Ergonomics

Background Minimally invasive surgery may introduce new ergonomic challenges for surgeons. Increased patient body mass index (BMI) may further add to this ergonomic stress. Objectives The objective of this study was to quantify the ergonomic impact of patient BMI on surgeons during laparoscopic surgery. Setting University Hospital, USA. Methods This prospective cohort study analyzed five minimally invasive surgeons during 24 laparoscopic procedures. Each subject’s muscle stress was assessed by recording surface electromyography (EMG) data from eight upper body muscle groups during laparoscopic procedures. EMG data was normalized against the maximal voluntary contraction (MVC) of each muscle measured before the start of surgery to create a percentage of the MVC value (%MVC). Subject workload was assessed through the NASA Task Load Index (NTLX). Statistical analysis was used to determine significance between surgeons operating on patients with or without obesity for %MVC and NTLX scores. Results There was no significant difference ( p > 0.05) in both the average muscle activation of all eight muscle groups and NTLX scores during laparoscopic surgery in surgeons operating on patients with BMI > = 30 compared with patients with a BMI < 30. Conclusions We detected no differences in ergonomic stress or workload for surgeons operating on patients with or without obesity. For surgeons, the laparoscopic approach may offer an additional advantage over open surgery in patients with obesity. This advantage may be due to an “equalizing effect” of laparoscopy—that surgical ergonomics are less affected by the BMI of the patient when using laparoscopic tools.