It refers to the removal of a cone-shaped tissue sample from the mucous membrane of the cervix.
Conization can be used for diagnostic purposes as part of a biopsy or for therapeutic purposes to remove precancerous cells .
The types include:
Cold knife conization : generally outpatient, occasionally inpatient.
Loop electrical excision procedure : usually outpatient.
Conization of the cervix is a common treatment for dysplasia after abnormal Pap test results.
The patient receives general anesthesia and adequate exposure of the cervix is obtained. The cervix is stained with the lugol solution to completely define all the areas that do not take up the iodine agent and thus demarcate the areas of glycogen depletion.
An incision that will surely include all abnormal areas is made in the mucous membrane of the ectocervix. Many believe that blood loss can be reduced by injecting a dilute antidiuretic hormone solution into the incision line before starting the procedure.
For this, lidocaine or xylocaine 1% with epinephrine will be injected around the entire surface of the cervix. Vascular constriction and scalding of the cervix will be noted. This technique may be contraindicated in patients with cardiovascular disease and / or hypertension .
A vascular cerclage of the waist to control bleeding is rarely indicated. With the lesion adequately stained with Lugo’s iodine solution, the device is placed outside the lesion in the area of the cervix.
It is adjusted and inserted through the cervical tissue to the necessary depth and is slowly moved from one side of the cervical os to the other side.
When inserting the device to the full depth of the cervix, the cone must contain the entire lesion. When the surgeon has reached the opposite limits of the lesion, as indicated by the iodine area, the instrument is lifted forward and the sample is removed.
Significant cervical stenosis, cervical incompetence, and infertility with a cervical factor are rare complications and are a function of the amount of endocervix removed. Several physicians advocate the use of the laser as a cervical tool instead of the knife in conization of the cervix.
Several studies have now shown that blood loss, infection, and stenosis in laser conization are essentially the same as those that occur in cold knife conization.
Some have suggested that less dysmenorrhea occurs after laser conization. Complication rates, in at least one study, were the same when laser vaporization was compared with laser conization.
Complications after an open cone procedure appear to be similar to those managed with a closed cone procedure (Sturmdorf or other suture). Although it has been suggested that the laser does not distort the cervical margins with respect to pathological evaluation, one article suggests that this is not the case.
The authors reviewed 77 laser conizations, of which 28 (36%) showed extensive epithelial denudation, 10 (13%) coagulation artifacts that made recognition of cervical intraepithelial neoplasia extremely difficult or impossible, and 11 (14%) showed artifacts. of lasers that produced the evaluation of the margins is extremely difficult or impossible.
In the United States, conization of the cervix is used primarily as a diagnostic tool and secondarily as a therapy for patients who are young and desire greater fertility.
However, in other countries, conization is used as definitive therapy. Extensive experience has been gained with this operative modality, particularly in the treatment of severe cervical intraepithelial neoplasia (CIN).
In Europe (especially Scandinavia), conization has been widely used to treat patients with cervical intraepithelial neoplasia, and some interesting data has been published.
Bjerre and associates reported on 2099 cases of women with abnormal vaginal smears in whom conization of the cervix had been performed.
The frequency of complications was considered low, and cervical carcinoma in situ was diagnosed in 1500 cases. Conization appeared to be curative in 87% of these 1,500 cases. The failure was related to whether the resection margins were free of pathological epithelium.
If Pap smears were repeatedly negative during the first year after conization, subsequent abnormal smears were found in only 0.4% of cases.
Kolstad and Klem reported on a series of 1121 patients with cervical carcinoma in situ who had been followed for 5 to 25 years.
Therapeutic conization was performed in 795 of these patients, of whom 19 (2.3%) had recurrent cervical carcinoma in situ and 7 (0.9%) developed invasive cancer. The corresponding figures for 238 patients treated with hysterectomy were, respectively, 3 (1.2%) and 5 (2.1%).
The invasive lesions noted appeared several years later, and the type of initial procedure did not have a significant influence.
Kolstad and Klem emphasized that women who have had cervical carcinoma in situ of the cervix will always be at risk and therefore must be followed carefully for a much longer time than the conventional 5-year period.
If conization has ruled out invasive cancer, those with free surgical margins have almost 100% disease-free follow-up.
Cold knife conization
Cold knife conizations have decreased considerably in frequency after the wide acceptance of the loop electrosurgical excision procedure.
However, the cold knife approach may be preferable in situations where evaluation of the margins is particularly critical or in situations where the use of a diathermic loop is impossible due to the proximity of the exocervical margin to the vaginal fornix.
In some centers, the cold knife approach is used exclusively if microinvasion or glandular injury is suggested. Cold knife conization should be performed in a fully equipped operating room under general, epidural, or spinal anesthesia.
Local anesthesia may be adequate in relaxed and highly cooperative patients, but unexpected movements and vaginal tension can interfere with an optimal conclusion.
Complications of the cold knife conization procedure
Cold knife conization can cause significant bleeding. Consequently, it is recommended to perform a preconization cerclage or inject the cervix with a vasoconstrictor solution , such as dilute vasopressin.
Infection is a possibility as with all surgical procedures. Cervical scarring and incompetent cervix are rare, but potentially serious risks.
Cervical scarring can hinder your efforts to get pregnant and can cause difficulties reading Pap tests. An incompetent cervix occurs when a very large area of the cervix has been removed.
The wide area of tissue shedding can increase your chances of preterm labor during pregnancy.
Loop electrical cleavage procedure
The loop electrosurgical excision procedure (LEEP) is one of the most widely used methods to treat high-grade cervical dysplasia (cervical intraepithelial neoplasia II / III, high-grade squamous intraepithelial lesion) discovered on examination. colposcopic.
In the UK it is known as large loop excision of the transformation zone.
The procedure has many advantages, including low cost, high success rate, and ease of use. The procedure can be performed in an office setting and typically only requires local anesthesia, although IV sedation or general anesthesia is sometimes used.
In doing this, the doctor uses a wire loop through which an electric current is passed at variable power settings.
Various shapes and sizes of loop can be used depending on the size and orientation of the lesion. The cervical transformation zone and the lesion are excised to an adequate depth, which in most cases is at least 8 mm and extends 4 to 5 mm beyond the lesion.
A second pass with a narrower cycle can also be performed to obtain an endocervical sample for later histological evaluation.
The loop electrosurgical excision procedure technique produces some thermal artifact in all samples obtained due to the use of electricity that simultaneously cuts and cauterizes the lesion, but this generally does not interfere with the pathological interpretation.
Complications of the electrical loop excision procedure
Complications are less common compared to cold knife conization, but can include infection and bleeding.
On the other hand, a case-control study has found an association between the surgical treatment of cervical intraepithelial neoplasia lesions and the risk of infertility or subfertility, with a odds ratio of approximately 2.
Cervical scarring is a theoretical mechanism that causes problems conceiving. This scar tissue can be massaged or ruptured in a number of ways, allowing the cervical opening to dilate back to its normal size.
A cohort study found that women with a time interval between the electrosurgical excision procedure and pregnancy of less than 12 months compared with 12 months or more had a significantly higher risk of miscarriage, with a risk of miscarriage of 18% compared to 4.6%, respectively.
On the other hand, no increased risk of preterm birth was identified after the loop electrosurgical excision procedure.
However, a large meta-analysis concluded that women with cervical intraepithelial neoplasia have a higher initial risk of preterm delivery than the general population and that the electrosurgical excision procedure as the treatment for cervical intraepithelial neoplasia is likely to further increase this risk.
Additionally, the risk of preterm birth appears to increase with multiple treatments and increasing amounts of tissue removed.
One study found that women reported a minimal, but statistically significant, decrease in sexual satisfaction after the loop electrosurgical excision procedure.
Risks after conization
The frequently asked question is: what should be the administration after conization if the surgical margins, particularly the endocervical margins, have disease present?
The considerable data in the literature suggest that the majority will have normal conization on cytology and that no additional treatment is necessary.
Anderson and his colleagues looked at 58 patients with positive surgical margins, and only three (5%) had persistent disease.
Lopes and colleagues noted in 75 similar patients that 9 (12%) had residual disease.
Grundsell found 3 of 21 patients with positive margins with residual disease. Our practice is to follow up all post-conization patients with cytology only regardless of the surgical margin and intervene only if the cytology is abnormal.