An indirect method to examine forces affecting Courvoisier's oblique gall-bladder incision

The aim of this study is to establish a method by which the maximum forces attacking Courvoisier's oblique gall-bladder incision can be evaluated. Nine well-informed patients served as subjects. Four investigations were made: pre-, per-, and two postoperative. The pre- and postoperative maximum isometric muscle strength in pulling forward were measured with a dynamometer. Simultaneously the IEMG was obtained. A muscle tensiometer was used for registration of the peroperative muscle pull of the right abdominal rectus muscle, and IEMG obtained simultaneously. The IEMG makes a calculation of the pre- and postoperative rectus muscle pull possible. The study seems to indicate that the most realistic estimation of the forces attacking the wound in the early postoperative phase is a preoperative measurement of the maximum force in pulling forward (attempted trunk bending). If ruptures in the wound occur during the extubation, ruptures would very likely also occur in the early postoperative phase. Eight weeks after the operation the right rectus muscle has regained its preoperative strength.