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Obstetrics & Gynecology 2005;106:128-130
© 2005 by The American College of Obstetricians and Gynecologists
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ORIGINAL RESEARCH

Topical Analgesia for Endometrial Biopsy

A Randomized Controlled Trial

Jon I. Einarsson, MD MPH, Gwendolyn Henao, MD and Amy E. Young, MD

From the Departments of Obstetrics and Gynecology, Landspitali-University Hospital, Reykjavik, Iceland, and Baylor College of Medicine, Houston, Texas.


   ABSTRACT
TOP
ABSTRACT
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Objective: To estimate whether benzocaine spray applied to the cervix and the endocervical canal before performing office endometrial biopsy improves patient comfort during the procedure.

Methods: Eighty-eight women were randomly assigned to receive either 20% benzocaine spray or placebo to the outside of the cervix and into the endocervical canal before an endometrial biopsy was performed. The main outcome measure was pain during the endometrial biopsy, assessed by a visual analog scale. Statistical analysis was performed using Wilcoxon rank-sum test and Student t test.

Results: There were no statistically significant differences between the study group and the control group in mean age, race, parity, body mass index, menopausal status, tenaculum use, or history of chronic pelvic pain. No statistically significant differences were found in median pain scores between the 2 treatment groups.

Conclusion: Topical benzocaine spray does not appear to offer effective pain control in patients undergoing an endometrial biopsy.

Level of Evidence: I

Endometrial biopsy is a common outpatient office procedure performed for various indications, such as abnormal uterine bleeding, postmenopausal bleeding, abnormal cytology, and infertility. Although patients frequently experience moderate-to-severe pain during endometrial biopsy, relatively few studies have investigated potential methods of pain relief for this procedure.1 The majority of prior studies evaluated the use of intrauterine anesthesia in women undergoing a concurrent office hysteroscopy and an endometrial biopsy.1,2 We were interested in evaluating the potential benefit of the benzocaine spray during an endometrial biopsy, because the use of a local anesthetic spray has a number of potential advantages over intracervical or paracervical injection for procedural analgesia. The application is painless, and there is no danger of bleeding and potentially less risk of intravasation and infection. Benzocaine spray acts in less than 30 seconds and the effects last approximately 15 minutes.3 Additionally, use of lidocaine spray has been associated with significant reduction of pain levels among patients undergoing office hysteroscopy.4 Therefore, our main objective was to evaluate the efficacy of benzocaine spray in reducing patient discomfort during a routine office endometrial biopsy.


   MATERIALS AND METHODS
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ABSTRACT
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
This was a randomized, double-blind, placebo-controlled trial comparing the efficacy of benzocaine spray with placebo for pain control in patients undergoing office endometrial biopsy. The study was conducted at Harris County Hospital District outpatient clinics at Baylor College of Medicine. Patient enrollment commenced in February 2004 and ended in August 2004. The study protocol was reviewed and approved by the Baylor College of Medicine Institutional Review Board.

Patients in which biopsy was medically indicated were considered eligible study participants. Exclusion criteria included pregnancy, suspected pelvic infection, known cervical stenosis, known sensitivity to benzocaine, epilepsy, significantly impaired respiratory or cardiac conduction functions, and active liver disease.

After providing their informed consent, subjects were randomized into 2 groups: endometrial biopsy with active medication in the form of topical benzocaine spray and endometrial biopsy with topical placebo spray. The placebo spray and the topical benzocaine spray were provided by Beutlich Pharmaceuticals (Waukegan, IL). They were packaged in identical containers, labeled only A or B. The identification code was broken at the completion of patient enrollment. We employed a simple 1:1 computer-generated patient randomization scheme, and sequentially numbered opaque sealed envelopes were used for treatment allocation. Intent-to-treat data analysis was employed.

Patients underwent a standard gynecological examination. A speculum was inserted into the vagina, and the cervix visualized. Aerosol spray containing either placebo or 20% benzocaine was applied to the outside of the cervix and then into the cervical canal with an extension cannula. The aerosol was applied via a pump mechanism with a 1/2 second dose (60 mg) applied to the cervix and a 1/2 second dose applied into the endocervical canal. These are the doses recommended by the manufacturer.3 Following application and a 1-minute interval, endometrial biopsy was performed with a 3.1-mm or 4-mm Pipelle catheter. Physicians were encouraged to use a 3.1-mm Pipelle if possible, but the choice of Pipelle size was left to the discretion of the individual physician. If a tenaculum was used, the spray was applied 1 minute before placement of the tenaculum and again 1 minute before performing the endometrial biopsy. The decision to use a tenaculum was also left to the discretion of the individual physician. Patients were asked to rate their pain level on a visual analog scale (VAS) from 0 (no pain) to 10 (worst pain ever). Rating was done before, during, and 1 minute after the biopsy. No further follow-up was scheduled.

We documented patient demographics such as age, parity, race, maternal weight and height, history of chronic pelvic pain, menopause, and indication for biopsy. We also documented potential confounders such as use of a tenaculum, number of passes, and size of the endometrial cannula used.

Assuming an {alpha} of 0.05, a ß error of 0.2, and a standard deviation of 2.5, 44 subjects were required in each arm to detect a difference between the 2 groups of 1.5 cm on a 10-cm VAS scale. Normality was assessed by visual inspection of the sample histograms and use of the Shapiro-Wilk test for normality. Because our primary outcome of variable of pain during sampling was ordinal and not normally distributed (range 0–10, no pain to worst pain ever), we used the Wilcoxon rank-sum test to compare distribution of pain scores between the 2 study groups. We also employed the Student t test for normally distributed data and the Wilcoxon rank-sum test for non–normally distributed data to compare the distribution of potential confounders within the 2 study groups. All P values were 2-sided, and those less than .05 were considered to indicate statistical significance. Statistical calculations were performed with SAS 8.2 (SAS Institute Inc, Cary, NC).


   RESULTS
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ABSTRACT
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
A total of 88 patients were enrolled in our study. Of these, 44 patients were randomized to receive the placebo spray, and 44 received the active topical analgesic (Fig. 1). Patient demographics were similarly distributed between the 2 treatment groups (Table 1). Several potential confounders seemed to be equally distributed between the 2 groups (Table 2). We found no statistically significant differences in mean pain scores between the benzocaine group and the placebo group during endometrial sampling or at 1 minute following endometrial sampling (Table 3).



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  		Fig. 1. Flow chart of study participants.

Einarsson. Analgesia for Endometrial Biopsy. Obstet Gynecol 2005.

 

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  		Table 1. Patient Demographics

 

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  		Table 2. Distribution of Potential Confounders

 

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  		Table 3. Median Pain Scores and Ranges in the Two Study Groups

 


   DISCUSSION
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ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
In our efforts to evaluate the efficacy of topical anesthetic spray for pain relief during endometrial biopsy, we were unable to detect a significant difference in pain scores between the 2 treatment groups. A potential explanation for these findings might be that pain perception from the cervix and the corpus of the uterus appear to travel through 2 distinct neural pathways. Innervation to the cervix arises from parasympathetic fibers from the pelvic splanchnic nerves (S2–4), which also supply the lower portion of the uterus. Pain perception from the fundus and body of the uterus travels up the hypogastric nerves to the lower thoracic spinal cord.5 The analgesia offered at the level of the cervix might therefore have been overshadowed by the pain experienced from the uterine corpus.6

There have been several conflicting reports on various methods of pain relief during an endometrial biopsy. A study by Dogan et al2 found that the combination of local lidocaine and oral naproxen sodium significantly reduced patient discomfort during an endometrial biopsy. However, when either lidocaine or naproxen sodium were given individually, there was no improvement in outcome. Trolice et al1 evaluated the use of intrauterine 2% lidocaine instilled with a catheter before endometrial biopsy and found a statistically significant reduction in pain over placebo in the treatment group. Davies et al7 reported that intrauterine application of lidocaine spray during hysteroscopy significantly reduced pain during grasping of the cervix, but not during endometrial biopsy. Similarly Lau et al8 found no pain relief in patients receiving 5 mL of 2% intrauterine lidocaine for outpatient diagnostic hysteroscopy and endometrial biopsy.

Our study has some important limitations. We found that, for some of our patients, the introducer was not long enough to reach the cervical canal. This may have reduced the potential efficacy of the active medication, although the proportion of patients affected was probably similar in both groups. This was formally reported in only 2 patients, but there might be a level of underreporting of this problem by the resident physicians. Our study was performed in a community clinic run by residents. Although the proper procedure was explained to the residents beforehand and one of the authors was present for the majority of biopsies, it is possible that some of the resident physicians did not adhere fully to the proposed guidelines, specifically the 1-minute waiting period following spray application to endometrial biopsy and/or use of appropriate dose of medication. Finally, because our patient population was mostly Hispanic, the results may not be applicable to other ethnic groups.

In conclusion, we were unable to detect a significant difference in pain scores in patients undergoing endometrial biopsy when comparing the use of local benzocaine spray with placebo. Based on our observations, we cannot recommend using topical benzocaine spray for pain relief in this patient population.


   Footnotes
 
Address reprint requests to: Jon I. Einarsson, MD, MPH, Department of Obstetrics and Gynecology, Landspitali-University Hospital Hringbraut, IS-101, Reykjavik, Iceland; e-mail: jonivar{at}yahoo.com.

doi:10.1097/01.AOG.0000165272.62416.61


   REFERENCES
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
1. Trolice MP, Fishburne C, McGrady S. Anesthetic efficacy of intrauterine lidocaine for endometrial biopsy: a randomized double-masked trial. Obstet Gynecol 2000;95:345–7.[Abstract/Free Full Text]

2. Dogan E, Celiloglu M, Sarihan E, Demir A. Anesthetic effect of intrauterine lidocaine plus naproxen sodium in endometrial biopsy. Obstet Gynecol 2004;103:347–51.[Abstract/Free Full Text]

3. Beutlich Pharmaceuticals. Hurricaine Topical Anesthetics. Available at: http://www.beutlich.com/hurricaine. Retrieved April 18, 2005.

4. Soriano D, Ajaj S, Chuong T, Deval B, Fauconnier A, Darai E. Lidocaine spray and outpatient hysteroscopy: randomized placebo-controlled trial. Obstet Gynecol 2000;96:661–4.[Abstract/Free Full Text]

5. Moore KL, Dalley AF. Clinically oriented anatomy. 4th ed. Philadelphia (PA): Lippincott Williams & Wilkins; 1999.

6. Van der Burght M, Schonemann NK, Laursen JK, Arendt-Nielson L, Bjerring P. Onset and duration of hypoalgesia following application of lidocaine spray on the genital mucosa. Acta Obstet Gynecol Scand 1994;73:809–11.[Medline]

7. Davies A, Richardson RE, O’Connor H, Baskett TF, Nagele F, Magos AL. Lidocaine aerosol spray in outpatient hysteroscopy: a randomized double-blind placebo-controlled trial. Fertil Steril 1997;67:1019–23.[Medline]

8. Lau WC, Tam WH, Lo WK, Yuen PM. A randomized double-blind placebo-controlled trial of intracervical intrauterine local anesthesia in outpatient hysteroscopy. BJOG 2000;107:610–3.[Medline]





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