New nomogram for safe laparoscopic entry to reduce vascular injury.

A nomogram is developed to determine the length of Veress needle that could be safely inserted to achieve pneumoperitoneum to reduce the risk of vascular injury during laparoscopic entry. Axial images of magnetic resonance imaging (MRI) were used to measure the vertical distance between umbilicus and retroperitoneal vessels (STR). This distance was correlated with body mass index and a nomogram was developed to exactly measure the safe distance for the length of Veress needle insertion. The fitted equation was STR (skin to rectus sheath) = 31.6 + 3.952 × BMI with adjusted R(2) = 94.5%. The abdominal cavity depth showed a correlation with adjusted R(2) = 84.2%. This showed a significant relation between body mass index and prediction of cavity depth. Using the mean regression line for STP (skin to peritoneum), a safe insertion distance was identified and a nomogram developed which can be used to objectively predict the depth of the peritoneal cavity.