Conization of the cervix is defined as excision of a cone-shaped or cylindrical wedge from the cervix uteri that includes the transformation zone and all or a portion of the endocervical canal. It is used for the definitive diagnosis of squamous or glandular intraepithelial lesions, for excluding microinvasive carcinomas, and for conservative treatment of cervical intraepithelial neoplasia (CIN).
While no recent changes have occurred in the technique of conization, a quadrivalent human papillomavirus (types 6, 11, 16, 18) recombinant vaccine (Gardasil) was introduced in 2006. Its widespread use is expected to reduce the number of cervical neoplasias, and, consequently the need for surgical interventions.
Conization can be performed with a scalpel (cold-knife conization), laser, or electrosurgical loop. The latter is called the loop electrosurgical excision procedure (LEEP) or large loop excision of the transformation zone (LLETZ). Combined conization usually refers to a procedure started with a laser and completed with a cold-knife technique. Laser conization can be excisional or destructive (by vaporization). Techniques for diagnostic and therapeutic conization are virtually identical. The extent of excision must be adjusted according to individual needs (see image below).
Conization site as related to uterine anatomy.
Each of these approaches has distinct benefits and disadvantages. Cold-knife conization provides the cleanest specimen margins for further histologic study, but it is typically associated with more bleeding than laser or LEEP, and it requires general anesthesia in most cases. Laser procedures are of longer duration and, especially if low-power density is used, may "burn" the margins, thus interfering with histologic diagnosis. The main advantage with this procedure is that dots produced by the laser energy can be used to accurately outline the exocervical margins. However, overall, the benefit of using laser for conization may not justify the high cost of the procedure.
LEEP procedures have several advantages, including rapidity, preservation of the margins for histologic evaluation, and virtual bloodlessness. Moreover, one can perform LEEP procedures in the office or in other outpatient settings.