There is no consensus on the definition of cervical stenosis, but from the hysteroscopy point of view, it could defined as the cervix that present a difficult access and require special maneuvers to introduce the hysteroscope into the cervical canal. Perhaps, the definition proposed by Bandalf defining cervical stenosis when the cervical canal does not allow the passage of a Hegar dilator 2.5 mm is more objective. Stenosis of the external os has been defined when there is less than 4.5 mm expansion. (2) Cervical stenosis and pain during the procedure, are the main causes of failure to perform in office hysteroscopy.
Cervical stenosis may be congenital or acquired. Congenital cervical stenosis is observed in the rare case of cervical atresia. Acquired is the most common cause of cervical atresia and is related to age, hormonal status and previous surgical procedures on the cervix.
Cervical stenosis may affect the external os, the internal os or the entire cervical canal. In all three locations, the most frequently affected by stenosis is the IO. Cervical stenosis is a condition that affects mainly postmenopausal women.
Technique to overcome cervical stenosis
When confronted with a stenotic cervix while performing in office hysteroscopy, we offer various alternatives that facilitates the access to the uterine cavity, which depend on the location and consistency of the cervical tissue adhesions.
Input optical rotation technique
Rigid optics have a bevel tip, which gives the capacity for tissue penetration and ability to separate the fibers. Most cases of cervical stenosis are solved by a rotational movement of the tip of hysteroscope to separate the fibrous tissue and allow to advance of the hysteroscope.
The use of biopsy forceps or hysteroscopic scissors help to overcome more severe cases that are not solved by the input optical rotation technique. The introduction of scissors or a closed clamp into the stenotic cervical canal and subsequent opened extraction, dilate the cervix just enough to introduce the tip of the hysteroscope. Sometimes the use of scissors is needed to cut the lateral corner of the cervical canal or fibrous tissue adhesions at the level of the internal os.
Entrance with bipolar electrode
The use of a bipolar electrode allows the section of the ring fibers of the cervix, extending the cervical os allowing the passage of the hysteroscope. These sections should be done at the level of the side edges of the cervical os.
Dilation with stems
There is evidence describing that the inyection of a dilute solution of vasopressin (0.05 U/mL) at the cervical stroma, significantly reduce the force needed to dilate the cervix. This technique could be an alternative when faced with a stenotic cervix in a patient that has not received pre-procedure prostaglanding to prime the cervix.
In certain situations, we face a real cervical disintegration in which we are unable to identify any recognizable structure and, of course, it is impossible to determine where the external os is located. Cervical disintegration often occurs in patients with history of invasive surgical procedures on the cervix such as traquelectomy or cold knife conization. In these patients access to the cervix represents a challenge and the use of ultrasound guide or cold cervical incision with a scalpel often allows access to the unstructured cervix. There are some case report describing hysteroscopic uterine access in patients with unstructured cervix. Shankar et al. reported a case of a 65 year old patient with postmenopausal bleeding in whom a cut of 15 mm performed with a cold knife was performed to introduce the hysteroscope into the uterine cavity.
Overcoming cervical stenosis in office hysteroscopy is challenging and often requires to abort the procedure and to take the patient to the operating room for treatment under general anesthesia.