Measurement of the force necessary for laparoscopic trocar entry.

A study was designed to measure the force necessary for trocar insertion before laparoscopy. A strain gauge was used to measure the force used with a reusable, pyramid-tipped trocar system sharpened at regular intervals and a disposable trocar system also with a pyramidal point and of equal diameter (10 mm). Variables studied for both groups, 50 patients each, included the type of incision made at the umbilicus; the opening and closing laparoscopic gas source pressure; the volume of gas delivered to create the pneumoperitoneum; the age, weight and height of the patient; and whether the laparoscopy was the first or a repeat. The variables were matched for both groups. The disposable device required half the force for entry required with the reusable device. Since many gynecologists are now women and thus may have less upper body strength than men do, this finding could be important for them. Further, the disposable trocar affords an operator of any size and strength greater control over the potentially dangerous trocar insertion into the abdomen since less force is required.