Is Intrauterine Anesthesia Beneficial for Performing Gynecologic Procedures?
Abstract & Commentary
By Frank W. Ling, MD, Clinical Professor, Departments of Obstetrics and Gynecology, Vanderbilt University School of Medicine and Meharry Medical College, Nashville, is Associate Editor for OB/GYN Clinical Alert.
Dr. Ling reports no financial relationships relevant to this field of study.
Synopsis: Instillation of local anesthesia into the uterine cavity can reduce pain for endometrial biopsy, curettage, hysteroscopy, and possibly other procedures.
Source: Mercier RJ, Zerden ML. Intrauterine anesthesia for gynecologic procedures: A systematic review. Obstet Gynecol 2012;120:669-677.
The authors performed a search of online databases as well as reference lists from published reviews that evaluated methods of pain control in gynecologic procedures using intrauterine instillations. Ultimately, 23 randomized, controlled trials (RCT) were deemed appropriate for inclusion in this systematic review. The two authors independently evaluated the quality of each article, using an independent reviewer if a disagreement occurred. A meta-analysis could not be performed due to the heterogeneity of the data in the studies. Conclusions could not be reached with regard to the efficacy of intrauterine anesthetic instillation in the case of induced abortion, intrauterine device insertion, tubal sterilization, and saline-infusion sonography. Moderate evidence provides support for its use in hysteroscopy. Although good evidence demonstrates that this technique is not useful in cases of hysterosalpingography, it is effective in reducing pain in endometrial biopsy and curettage.
This article is an excellent example of how peer- reviewed literature can answer a valuable clinical question. Mercier and Zerden conducted a methodologically sound review of 23 RCTs assessing the effectiveness of intrauterine instillation for outpatient endometrial procedures and summarized the findings in a logical and systematic fashion. This article is a real clinical gem since it serves as a “this-is-what-science-has-learned-about-this-subject-up-to-now” statement while presenting conclusions in a clinically accessible way. An added bonus of this article is the authors’ review of the innervations of the uterine cavity (there are 2 plexus — the better known Frankenhauser plexus, which is targeted by the paracervical block, as well as other endometrial nerve plexus) and reminds us of appropriate dosing of common anesthetic medications (most of the studies used a maximum of 200 mg of xylocaine® [lidocaine] which is 20 mL of a 1% solution).
The authors also address why they believe this practice has not become more popular among practitioners. Possible explanations include lack of clinical effectiveness of intrauterine instillation, lack of awareness of research in this area, attitude that the procedure is not painful enough to warrant anesthesia, perceived risk of intrauterine infection, and perceived disruption to the usual workflow in the office. I would offer the possible addition of potential financial implications, because insurers may not universally pay for the equipment and supplies needed to provide intrauterine instillation, whereas a paracervical block has a recognized CPT code that is more likely reimbursable.
Another service of this article is that the authors point out that the quality of research in this area heretofore certainly leaves room for further investigation. Until data from larger RCTs are available, we might wish to put into practice the findings of the best current literature. This review provides good evidence that intrauterine instillation of a local anesthetic reduces pain in endometrial biopsy, endometrial curettage, and possibly hysteroscopy. Although the literature does not currently support its use in other procedures, further research might change that landscape. Until then, our patients’ comfort is worth our consideration.