HOT-KNIFE CONIZATION OF THE CERVIX - CLINICAL AND PATHOLOGICAL FINDINGS FROM A STUDY INTRODUCING A NEW TECHNIQUE

Objective: To introduce an alternative method for conization of the ce rvix using a Teflon-coated hot knife and to evaluate thermal distortio n, adequacy of excision, operating time, blood loss, and short- and lo ng-term effects of this method. Methods: Between 1987-1993, 88 patient s underwent cervical conization using a Teflon-coated hot knife at tem peratures ranging from 110-130C. Histopathologic slides were reviewed simultaneously by two pathologists, who assessed thermal distortion, a dequacy of excision, and interpretability of the surgical margins. Cli nical information was obtained prospectively, including operating time , blood loss, and depth and volume of the excised cone. In addition, d ata were accumulated retrospectively from 40 randomly selected patient s who underwent cold-knife conization between 1985-1990. Short- and lo ng-term data were assessed for healing and scarring and the adequacy o f postoperative Papanicolaou smears in the hot-knife patients. Results : Thermal injury was minimal, with 300 mu or less in 83 patients (92%) and 350-600 mu in four patients. One patient had thermal distortion o f 1500 mu. All slides were interpreted adequately. Blood loss was mild to moderate in 84 of 88 patients (95%) in the hot-knife group and in 34 of 40 patients (85%) in the cold-knife group. No patient in the hot -knife group needed blood transfusion or hospitalization. Operating ti me was reduced by as much as 67% when the hot knife was used. Thirteen percent of the hot-knife patients developed stenosis of the external as. No patient in the hot-knife group developed recurrence within 2 ye ars of surgery. Conclusion: Using a Teflon-coated hot knife for coniza tion of the cervix produces adequate surgical margins and reduces bloo d loss and operating time over that with cold-knife conization. Long-t erm follow-up reveals no increase in cervical stenosis and demonstrate s adequate cytologic smears in the hot-knife patients. (Obstet Gynecol 1994;83: 97-103)