Comparison of the ClearView uterine manipulator with the Cohen cannula in laparoscopy

The ClearView Uterine Manipulator was compared with the Cohen acorn-tipped cannula for efficacy and safety in patients undergoing laparoscopy at the University of Utah Medical Center. Fifty consecutive patients were randomized by computer to have either the ClearView instrument or the Cohen cannula used as a uterine manipulator (25 patients each). The ClearView manipulator was statistically superior to the Cohen cannula for range of motion in the anterior and posterior sagittal plane (p <0.0001). The Cohen cannula was consistently inserted in less time (p <0.02). There was no statistically significant difference between the instruments in ease of uterine manipulation, ease of dye instillation, percentage of dye leakage from the cervix, overall ease of use, ease of device insertion, and ease of device removal. Two cervical perforations occurred during cervical dilatation in the ClearView manipulator group in patients with cervical stenosis requiring dilatation with metal dilators (os <2 mm). No patients in the Cohen cannula group had cervical stenosis. In that group two cervical lacerations occurred requiring suture ligation. The ClearView instrument provides a greater range of motion, does not require an assistant to maintain uterine position, and allows manipulation without a cervical tenaculum. Its insertion occasionally (36%) required tenaculum placement, uterine sounding, and cervical dilatation, increasing the time of insertion compared with placement of the Cohen cannula. In patients with cervical stenosis, use of a uterine sound and cervical dilatation increase the risk of perforation.