Afifi et al developed tools for determining the length of a Veresa needle needed for pneumoperitoneum during abdominal laparoscopic surgery. The goal is to have a needle long enough to enter but not long enough to injury retroperitoneal vessels. The authors are from Birmingham Women's Hospital, the University of Birmingham and Chelsea and Westminister Hospital in London.


Patient selection: females with body mass index from 15 to 40 kg per square meter


distance in mm from skin at pit of umbilicus to rectus sheath = STP =

= (0.7306 * (BMI)) + 0.864


distance in mm from skin at pit of umbilicus to anterior surface of retroperitoneum = STR = (3.952 * (BMI)) + 31.6


abdominal cavity depth in mm = distance between STP and STR =

= (3.222 * (BMI)) + 35.3


From the nomogram in Figure 2

Nomogram Line

Distance in mm from Skin in Umbilical Pit

pierce skin and rectus sheath to enter abdominal cavity

(0.7223 * (BMI)) - 1.096

mean distance from skin to retro-peritoneal vessels

(4.336 * (BMI)) - 41.71

lower limit of distance to retro-peritoneal vessels that includes safety margin

(4.307 * (BMI)) - 52.39


The authors recommended that the trocar be inserted using a 2-hand technique with the controlling hand adjusted to a safe length.


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