Laser conization assisted by crypt visualization for cervical intraepithelial neoplasia

Objective: To describe intraoperative visualization of crypts and its effects on specimen clearance, safety, and clinical results of excisional treatment of cervical intraepithelial neoplasia (CIN). Methods: We treated 147 patients with high-grade CIN (II-III) and colposcopically-assessed endocervical extension, using a CO₂ laser instrument in a day-hospital setting. Endocervical walls were stained preoperatively with a 2% methylene blue aqueous solution. Cervical conization was done by laser under colposcopic vision. Stromal incision and cone shape were directed laterally to the endocervical crypts by intraoperative visualization in transparency of the stain. Results: We were able to make stromal incisions at minimal and uniform radial distances from the cervical canal, thus allowing individualized cone shape and optimal bleeding control. Median (range) base diameter and height of specimens were 18 (13-24) and 20 (15-26) mm, respectively. The final histologic diagnosis was CIN II in 35 patients, CIN III in 111, and microinvasive carcinoma in one. Endocervical disease extension was confirmed in 103 patients (70%) the median (range) length of CIN in the 99 evaluable cases was 15.6 (0.5-25.7) mm, and crypt involvement was found in 39 (26.5%). All lateral margins were free of dysplasia. Four specimens (2.7%) had positive apical margins. No significant complications occurred, and fertility did not seem to be impaired. With a median (range) follow-up period of 68 (60-92) months, only 1.4% of patients experienced recurrence; two patients, both with involved crypts, had recurrent dysplasia at 23 and 45 months, respectively. Conclusion: Laser microsurgical conization assisted by crypt visualization facilitates safe and complete removal of CIN extending into the endocervix.