For most diagnostic and many operative procedures, effective cervical anesthesia is obtained using local anesthesia, allowing the hysteroscopy to be done in an office procedure room. Evidence suggests that the paracervical block may be the most effective (208,209). Following exposure of the cervix with a vaginal speculum, a spinal needle can be used to instill about 3 mL of 0.5% to 1% lidocaine into the anterior lip of the cervix to allow attachment of a tenaculum and manipulation of the exocervix. While the exact location and depth of the injection varies with providers and studies, the uterosacral ligament location (about 4 mm deep at approximately at the 4-and 8-o’clock positions as one looks at the cervix) was demonstrated successful (210). Care must be taken to avoid intravascular injection. An alternative technique is the use of an intracervical block where the anesthetic agent is injected evenly around the circumference of the cervix, attempting to reach the level of the internal os. The efficacy of this approach is unclear based on published studies (208). Recognizing the complex innervation of the uterus, alternative or additional topical anesthesia may be applied to the cervical canal or to the endometrium, or both, using anesthetic spray, gel, or cream. It is unclear how effective these approaches are because many of the study protocols seemed to allow inadequate time between application and initiation of the procedure (211). A number of options were presented, including instillation of 5 mL of 2% mepivacaine into the endometrial cavity with a syringe, or the application of similar amounts of 2% lidocaine gel. Many operative procedures can be performed with these techniques combined, if deemed necessary, with the oral or intravenous use of anxiolytics or analgesics, although the use of such systemic agents mandates continuous monitoring of blood pressure and oxygenation and the availability of appropriate resuscitative staff and equipment. An important component of the optimal use of local anesthesia is allowing sufficient time from the injection or application of the agents before the commencement of the procedure. While injectable local anesthetic agents such as lidocaine and mepivacaine may have an onset of action in 2 to 3 minutes, it may take up to 15 to 20 minutes to obtain a maximal effect. If local anesthesia is not deemed appropriate, regional or general anesthesia may be used in the context of a surgical center or operating room.
Cervical Dilation In many instances, and particularly in vaginally parous women, dilation of the cervix will be unnecessary, especially if narrow caliber hysteroscopic systems are used. Dilation will be necessary some of the time, and, although seemingly simple, cervical stenosis or suboptimal technique can result in perforation that compromises the entire procedure. If the objective lens of the endoscope cannot be placed in the endometrial cavity the hysteroscopy cannot be done. The process of dilation should be undertaken carefully, respecting the orientation of the cervix to the axis of the vaginal canal (version) and that of the corpus to the cervix (ﬂexion). In difficult circumstances, simultaneous ultrasound may be valuable, and difficult dilation may be facilitated directly with the hysteroscope.