Body mass index (BMI) and forensic autopsy: association with procedural duration, technical complexity and operator vigilance

: Body mass index (BMI) is routinely recorded in forensic autopsy practice and represents a well-established risk factor for numerous natural causes of death. However, its role as a procedural modifier influencing autopsy workflow, technical complexity, and operator cognitive performance has not been systematically investigated. This study aimed to evaluate the impact of BMI on autopsy duration, anatomical-technical difficulty, and operator vigilance under standardized medico-legal conditions.A total of 50 consecutive medico-legal autopsies performed for natural deaths were prospectively analyzed, including an obese cohort (n = 25, BMI ≥ 30 kg/m²) and a non-obese control group (n = 25, BMI < 30 kg/m²), matched for age and sex and examined using an identical standardized autopsy protocol. The term "consecutive" refers to all eligible medico-legal autopsies for natural deaths performed during the study period, excluding cases of violent or suspicious death and those not meeting inclusion criteria. The cases were collected over a period of approximately six months, during which all qualifying autopsies were prospectively included. Body mass index was analyzed both as a continuous variable and according to obesity severity classes. Autopsy duration was objectively measured from the first skin incision to completion of organ removal. Operator vigilance was assessed using the Mackworth Clock Test, administered to both primary and secondary operators immediately before and after each autopsy. Morphometric assessment of subcutaneous adipose tissue thickness at the thoracoabdominal incision site and qualitative evaluation of technical difficulty were also performed.Autopsy duration was significantly longer in obese cases compared with controls (mean 219.6 ± 26.9 vs. 184.2 ± 14.9 min; p < 0.001), with a progressive increase across obesity classes. Within the obese cohort, BMI was a significant predictor of procedural duration, with an estimated increase of approximately 4 min per BMI unit. Increased autopsy duration was associated with an exploratory signal of vigilance decrement, which was greater in obese cases than in controls. Each additional 30 min of procedural time was associated with an increase of approximately one missed critical stimulus on post-autopsy vigilance testing. In all cases with BMI ≥ 35 kg/m², subcutaneous adipose tissue thickness exceeded 4 cm, correlating with deeper incision planes, delayed cavity access, and increased technical difficulty.These findings suggest that obesity may act as a procedural modifier in forensic autopsy practice and support further investigation of workload-related cognitive effects under standardized conditions.