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Intrauterine lignocaine gel did not significantly reduce pain during endometrial sampling
GYNECOLOGY
Intrauterine lignocaine gel did not significantly reduce pain during endometrial sampling Kozman E, Collins P, Howard A, AkanmuT,Gibbs A, Frazer M.The effect of an intrauterine application of two percent lignocaine gel on pain perception during Vabra endometrial sampling: a randomised double-blind, placebo-controlled trial. Br J Obstet Gynaecol 2001; 108: 87^90.
OBJECTIVE To determine if intrauterine lignocaine gel is e¡ective in reducing the pain of endometrial sampling in women with abnormal vaginal bleeding. DESIGN Randomized, triple-blind, placebocontrolled trial. Allocation was by blocked randomization list held by the pharmacy, using coded medications.The study had su⁄cient power to detect a relative di¡erence of 50% in the proportion of women experiencing high levels of pain. SETTING Hospital in the UK. SUBJECTS Three hundred and eight women, aged 22^82 (mean 51) years, who were undergoing endometrial sampling for investigation of abnormal vaginal bleeding. 97% of women were parous. 31% of women were postmenopausal and 32% were taking hormone replacement therapy. INTERVENTION One hundred and ¢fty-seven women were randomized to receive intrauterine application of 2% lignocaine gel and 151 women to receive placebo. An 11mL syringe attached to a 3 mm quill was used to apply 1mL of gel to the cervical lip and the remainder into the uterine cavity from within the cervical canal. About 3 min later, the 3 mm
Commentary The use of topical anesthetics for reducing pain during endometrial biopsy and office hysteroscopy is an interesting topic. In the early 1990s, studies suggesting that topical anesthetics were effective were usually of small sample size or non-randomized. Since the late 1990s, large-scale randomized trials repeatedly have shown a lack of effectiveness or limited effectiveness mainly during cervical manipulation (e.g. application of the tenaculum), whereas no significant pain relief was observed during intrauterine manipulation (e.g. uterine distension and endometrial biopsy). The present study showed that intrauterine lignocaine gel application did not significantly reduce pain during Vabra endome-
192
Evidence-based Obstetrics and Gynecology (2001) 3,192^193 doi:10.1054/ebog.2001.0296, available online at http://www.idealibrary.com.on
cannula of the Vabra sampling device was inserted into the uterine cavity. Suction was used to curette the endometrial cavity three times. Prior to and 5 min following the procedure and 5 min following it, the women assessed their pain on a visual analogue scale of 0^10 and completed an anxiety inventory. MAIN OUTCOME MEASURES Proportion of women with pain score 6 after the procedure. MAIN RESULTS Pain scores were missing for 8% of women in each group. The proportion of women with pain score 6 after the procedure was 38/145 (26%) in the lignocaine group and 46/139 (33%) in the placebo group (p=0.20*, relative risk [RR] 0.8, 95% CI 0.6^1.1). Anxiety levels were higher than normal prior to the procedure and were reduced slightly afterwards, to a similar extent in both groups. CONCLUSION Compared to placebo, the use of intrauterine lignocaine gel did not signi¢cantly reduce the proportion of women who experienced high levels of pain during endometrial sampling for abnormal vaginal bleeding. * Calculated from data in article.
trial aspiration. The sample size provided sufficient power to demonstrate the desired clinical difference. The study was well designed concerning randomization and blinding. A similar study on intrauterine lignocaine in outpatient hysteroscopy also demonstrated the ineffectiveness of this treatment in reducing pain during hysteroscopy and endometrial biopsy.1 However, with the inclusion of hysteroscopy, its implication is quite different from that of the present trial, which assessed pain with endometrial sampling alone. The site of application of lignocaine in the present study was actually more endocervical than intrauterine: ‘The quill was then introduced into the cervical canal beyond the external os, but not through the internal os, and the rest of the gel was then & 2001Elsevier Science Ltd
applied’.With the tip of the quill not being right inside the uterine cavity, instillation of the gel would lead to significant backflow of the gel. Thus, the exact amount of gel being injected into the uterus was probably small and inconsistent.With the innervation pattern of the uterine corpus and cervix as described in the article, it is not difficult to understand why lignocaine did not work in this study. In another randomized, double-blinded trial, the authors instilled lignocaine or placebo through the endocervix into the uterine cavity, using an18 -gauge angiocatheter advanced to the hub, and the angiocatheter was left in place for 3 min before it was withdrawn, to prevent backflow.2 A significant reduction of pain during endometrial biopsy using the Pipelle instrument was demonstrated. The sample size, however, was much smaller than that of the present study. The use of a pain score of 6 as the cutoff point for ‘unacceptable’ pain was described as ‘arbitrary’ by the authors. As pain is a subjective experience, a pain score of 6 may be unacceptable to some women but well tolerated by others. Most studies would compare instead the difference between the mean pain scores of different study groups.
& 2001Elsevier Science Ltd
From the results of this study, the described method of lignocaine application was not effective in reducing unacceptable levels of pain or anxiety during endometrial sampling using the Vabra aspirator. A more refined method of genuine intrauterine instillation of lignocaine should be considered as an area for further exploration, bearing in mind that the method should be as simple and convenient as the well-tolerated 1-min procedure of endometrial sampling itself. AliceYuen Kwan Wong, MBBS Kwong Wah Hospital, Hong Kong, China
Literature cited 1. Lau WC, Tam WH, Lo WK, Yuen PM. A randomised doubleblind placebo-controlled trial of transcervical intrauterine local anaesthesia in outpatient hysteroscopy. Br J Obstet Gynaecol 2000; 107: 610 ^ 613. 2. Trolice MP, Fishburne Jr C, McGradu S. Anesthetic efficacy of intrauterine lidocaine for endometrial biopsy: a randomized double-masked trial. Obstet Gynecol 2000; 95: 345^347.
Evidence-based Obstetrics and Gynecology (2001) 3,192^193
193
Intrauterine lignocaine gel did not significantly reduce pain during endometrial sampling Kozman E, Collins P, Howard A, AkanmuT,Gibbs A, Frazer M.The effect of an intrauterine application of two percent lignocaine gel on pain perception during Vabra endometrial sampling: a randomised double-blind, placebo-controlled trial. Br J Obstet Gynaecol 2001; 108: 87^90.
OBJECTIVE To determine if intrauterine lignocaine gel is e¡ective in reducing the pain of endometrial sampling in women with abnormal vaginal bleeding. DESIGN Randomized, triple-blind, placebocontrolled trial. Allocation was by blocked randomization list held by the pharmacy, using coded medications.The study had su⁄cient power to detect a relative di¡erence of 50% in the proportion of women experiencing high levels of pain. SETTING Hospital in the UK. SUBJECTS Three hundred and eight women, aged 22^82 (mean 51) years, who were undergoing endometrial sampling for investigation of abnormal vaginal bleeding. 97% of women were parous. 31% of women were postmenopausal and 32% were taking hormone replacement therapy. INTERVENTION One hundred and ¢fty-seven women were randomized to receive intrauterine application of 2% lignocaine gel and 151 women to receive placebo. An 11mL syringe attached to a 3 mm quill was used to apply 1mL of gel to the cervical lip and the remainder into the uterine cavity from within the cervical canal. About 3 min later, the 3 mm
Commentary The use of topical anesthetics for reducing pain during endometrial biopsy and office hysteroscopy is an interesting topic. In the early 1990s, studies suggesting that topical anesthetics were effective were usually of small sample size or non-randomized. Since the late 1990s, large-scale randomized trials repeatedly have shown a lack of effectiveness or limited effectiveness mainly during cervical manipulation (e.g. application of the tenaculum), whereas no significant pain relief was observed during intrauterine manipulation (e.g. uterine distension and endometrial biopsy). The present study showed that intrauterine lignocaine gel application did not significantly reduce pain during Vabra endome-
192
Evidence-based Obstetrics and Gynecology (2001) 3,192^193 doi:10.1054/ebog.2001.0296, available online at http://www.idealibrary.com.on
cannula of the Vabra sampling device was inserted into the uterine cavity. Suction was used to curette the endometrial cavity three times. Prior to and 5 min following the procedure and 5 min following it, the women assessed their pain on a visual analogue scale of 0^10 and completed an anxiety inventory. MAIN OUTCOME MEASURES Proportion of women with pain score 6 after the procedure. MAIN RESULTS Pain scores were missing for 8% of women in each group. The proportion of women with pain score 6 after the procedure was 38/145 (26%) in the lignocaine group and 46/139 (33%) in the placebo group (p=0.20*, relative risk [RR] 0.8, 95% CI 0.6^1.1). Anxiety levels were higher than normal prior to the procedure and were reduced slightly afterwards, to a similar extent in both groups. CONCLUSION Compared to placebo, the use of intrauterine lignocaine gel did not signi¢cantly reduce the proportion of women who experienced high levels of pain during endometrial sampling for abnormal vaginal bleeding. * Calculated from data in article.
trial aspiration. The sample size provided sufficient power to demonstrate the desired clinical difference. The study was well designed concerning randomization and blinding. A similar study on intrauterine lignocaine in outpatient hysteroscopy also demonstrated the ineffectiveness of this treatment in reducing pain during hysteroscopy and endometrial biopsy.1 However, with the inclusion of hysteroscopy, its implication is quite different from that of the present trial, which assessed pain with endometrial sampling alone. The site of application of lignocaine in the present study was actually more endocervical than intrauterine: ‘The quill was then introduced into the cervical canal beyond the external os, but not through the internal os, and the rest of the gel was then & 2001Elsevier Science Ltd
applied’.With the tip of the quill not being right inside the uterine cavity, instillation of the gel would lead to significant backflow of the gel. Thus, the exact amount of gel being injected into the uterus was probably small and inconsistent.With the innervation pattern of the uterine corpus and cervix as described in the article, it is not difficult to understand why lignocaine did not work in this study. In another randomized, double-blinded trial, the authors instilled lignocaine or placebo through the endocervix into the uterine cavity, using an18 -gauge angiocatheter advanced to the hub, and the angiocatheter was left in place for 3 min before it was withdrawn, to prevent backflow.2 A significant reduction of pain during endometrial biopsy using the Pipelle instrument was demonstrated. The sample size, however, was much smaller than that of the present study. The use of a pain score of 6 as the cutoff point for ‘unacceptable’ pain was described as ‘arbitrary’ by the authors. As pain is a subjective experience, a pain score of 6 may be unacceptable to some women but well tolerated by others. Most studies would compare instead the difference between the mean pain scores of different study groups.
& 2001Elsevier Science Ltd
From the results of this study, the described method of lignocaine application was not effective in reducing unacceptable levels of pain or anxiety during endometrial sampling using the Vabra aspirator. A more refined method of genuine intrauterine instillation of lignocaine should be considered as an area for further exploration, bearing in mind that the method should be as simple and convenient as the well-tolerated 1-min procedure of endometrial sampling itself. AliceYuen Kwan Wong, MBBS Kwong Wah Hospital, Hong Kong, China
Literature cited 1. Lau WC, Tam WH, Lo WK, Yuen PM. A randomised doubleblind placebo-controlled trial of transcervical intrauterine local anaesthesia in outpatient hysteroscopy. Br J Obstet Gynaecol 2000; 107: 610 ^ 613. 2. Trolice MP, Fishburne Jr C, McGradu S. Anesthetic efficacy of intrauterine lidocaine for endometrial biopsy: a randomized double-masked trial. Obstet Gynecol 2000; 95: 345^347.
Evidence-based Obstetrics and Gynecology (2001) 3,192^193
193