Evaluation of the cone biopsy excisor compared with the large loop for electrosurgical excision of cervical lesions

Data incorporated from August 1994 to July 30, 1997.Objective: To compare a newly designed triangular electrode, the Cone Biopsy Excisor to the loop electrode with respect to the margin evaluation, fragmentation, and thermal damage of the conization specimen.Methods: After approval by the Institutional Review Boards of Hartford Hospital, St. Francis Hospital, and New Britain General Hospital/University of Connecticut, patients were randomly assigned to undergo conization with the Cone Biopsy Excisor or with the large loop. Inclusion criteria included biopsy proven CIN II, CIN III, inadequate colposcopy, positive endocervical curettage, or cytohistological discrepancy. Exclusion criteria included pregnancy, undiagnosed uterine bleeding, and invasive carcinoma. The procedures were performed by senior residents on clinic patients at the respective institutions. In addition, after FDA approval November 18, 1996, private OB/GYN practitioners performed cases and added those results to the study. Seventy-eight patients were randomized to the Cone Biopsy Excisor, while 77 patients were randomized to the loop electrosurgical excision procedure (LEEP). To obtain the surgical specimen, Force 2 Valley Lab generators were used with wattage ranging from 35 to 50 according to the size of the instrument chosen, 40/60 blend of coagulation, and cutting current.Pathology reports were reviewed to determine the amount of fragmentation that occurred during the procedure and for tissue diagnosis. Specimens were then evaluated by two gynecologic pathologists blinded to the instrument used. The specimens were analyzed for the ability to evaluate the margins and for degree of thermal damage. A thermal damage score was assigned to each specimen. The scoring system results in 4 levels of thermal damage, from one (minimal thermal damage) to four (heavy thermal damage). Follow-up data was obtained from the patients' medical and pathology records.Results: Seventy-two of 78 (92%) Cone Biopsy Excisor cases vs 10 of 77 (13%) LEEP cases submitted one specimen to pathology, P <.001 based on a chi(2) test. Mean number of specimens submitted to pathology per case in the Cone Biopsy Excisor group was 1.1 +/- 0.5 vs 2.2 +/- 0.8 in the LEEP group, P <.001 based on a t test. Margins were unable to be interpreted because of thermal damage in 2 of 78 (3%) in the Cone Biopsy Excisor group vs 14 of 77 (18%) in the LEEP group, P <.003 based on a chi(2) test.Conclusion: The Cone Biopsy Excisor provided a cervical specimen that had less fragmentation and less thermal damage with margins that were less likely to be indeterminate than those obtained with the large loop electrosurgical procedure.