Anthropometric measurements of the abdominal wall: toward standardization and difficulty grading in rTAPP inguinal

Robotic-assisted procedures in hernia surgery are highly standardized, whereas the distance between the ports and the target organ is of critical importance. To date, anthropometric data regarding the distance from the umbilicus to the symphysis and the Abdominal Elevation Angle (AEA) are lacking, both of which may be relevant for preoperative estimation of procedural difficulty and for the standardization of the surgical technique. This study prospectively evaluated anthropometric abdominal wall parameters and their influence on procedural difficulty in robotic-assisted groin hernia repair.

Abdominal wall elasticity was assessed by measuring xiphopubic, xiphoumbilical, umbilicopubic, and transversal distances before and after pneumoperitoneum at 12 mmHg. The abdominal elevation angle (AEA) was measured photographically and categorized as narrow (<23.8°), normal (23.9°-40.0°), or wide (>40.1°). Intraoperative anatomical features including intra-abdominal fat, peritoneal thickness, and adhesions were recorded using Likert scales.

Sixty-eight consecutive patients (61 male, 7 female; mean age 65 years, mean BMI 25.3 kg/m²) undergoing elective robotic-assisted groin hernia repair were included between July 2020 and April 2021. A total of 96 hernia sides were operated, including 28 bilateral and 8 recurrent cases. All distances increased significantly under pneumoperitoneum (p < 0.0001); the mean umbilicopubic distance with pneumoperitoneum was 16.35 cm. Mean longitudinal elasticity was 13.74% and transversal elasticity 11.73%, with no statistically significant difference between the two directions (p = 0.0844). Neither AEA nor BMI showed a statistically significant correlation with procedural difficulty. However, multiple linear regression analysis identified longitudinal abdominal wall elasticity as an independent predictor of procedural difficulty (p = 0.0139). Surgeon satisfaction with the procedural outcome was consistently high across all patient groups (mean score of 9.76/10), regardless of BMI or AEA.

The mean umbilicopubic distance is less than the 20 cm proposed as distance-to-target in robot-assisted procedures; the umbilicus is not ideal for positioning of the endoscope port. Longitudinal abdominal wall elasticity appears to be a relevant factor influencing the difficulty of robot-assisted groin hernia repair, whereas BMI and AEA alone are insufficient predictors.