Association Between Linea Alba Morphology and Abdominal Wall Distensibility During Pneumoperitoneum

The linea alba is subjected to the greatest tensile stress during anterior abdominal wall loading and plays a central role in maintaining mechanical stability. During pneumoperitoneum, abdominal wall behavior under controlled intra-abdominal pressure may reflect structural properties of its fascial components. This study examined the association between linea alba morphology and abdominal wall distensibility during pneumoperitoneum in laparoscopic surgery.

A retrospective observational cohort study was conducted in 343 patients undergoing laparoscopic surgery between February 2023 and December 2024. Abdominal wall distensibility during pneumoperitoneum was approximated by insufflated gas volume adjusted for body habitus under standardized anesthetic and pressure conditions. Preoperative computed tomography was used to assess interrectus distance (IRD) as a morphologic measure of the linea alba. Associations between IRD, abdominal distensibility, and body mass index (BMI) were analyzed.

The median IRD was 15.4 mm; 29.1% of patients had IRD ≥2 cm and 9.9% ≥3 cm, with wider IRD more frequently observed in female patients. Abdominal distensibility did not differ between patients with normal linea alba width (IRD <2 cm) and those with moderate widening (IRD 2 to 3 cm). In contrast, considerable widening of the linea alba (IRD ≥3 cm) was associated with higher abdominal distensibility, particularly among patients with lower BMI. Both IRD distribution and abdominal distensibility differed across BMI categories; patients with BMI ≥25 demonstrated significantly wider IRD but significantly lower abdominal distensibility compared with those with BMI <25, indicating that abdominal wall distensibility reflects the combined influence of IRD magnitude and body composition. In multivariable analysis, IRD ≥3 cm, BMI, and age were independent predictors of abdominal distensibility.

Linea alba morphology was associated with greater abdominal wall distensibility during pneumoperitoneum, particularly with larger separations. While abdominal distensibility is influenced by multiple factors, linea alba morphology represents an independent structural contributor to abdominal wall mechanics. Assessment of abdominal wall behavior under standardized insufflation conditions may complement morphologic evaluation and improve understanding of interindividual variability in laparoscopic surgery.