The effect of topical lignocaine gel in pain relief for colposcopic assessment and biopsy: is it useful?
Dr GCY Wong, The Family Planning Association of Hong Kong, 9/F, Southorn Centre, 130 Hennessy Road, WanChai, Hong Kong, China. Email email@example.com
We investigated the use of topical ligocaine gel in pain relief for colposcopy and cervical punch biopsy. Ninety women referred for colposcopy due to abnormal cervical cytology were randomised to receive 5 ml of either 2% xylocaine gel or KY jelly to the cervix and the upper part of the vagina for at least 10 minutes prior to the colposcopic procedures. Pain score was obtained at several points of the procedure. Topical lignocaine gel did not significantly relieve pain from cervical punch biopsy and alleviate the stinging sensation from application of acetic acid and Lugol’s iodine to cervix and vagina. However, it may be beneficial to a subgroup of women with prior unpleasant experience towards speculum examination.
Women may experience discomfort during colposcopic procedure. Discomfort arises not only from the biopsy procedure. Application of acetic acid and Lugol’s iodine may also give rise to stinging sensation to some women, especially those with active vaginitis. Previous studies on topical anaesthetics for colposcopy showed conflicting results. One study1 noticed a significant reduced pain score during cervical biopsy after the use of benzocaine gel, while another study2 showed no beneficial effect of topical xylocaine during colposcopic biopsies. A randomised double-masked study showed no advantage of topical benzocaine gel, either alone or together with oral ibuprofen, in decreasing colposcopy pain.3 In that study, only 2 ml of 20% benzocaine topical gel was applied to the cervix for 2 minutes. Such amount of anaesthetic gel might not be able to alleviate discomfort associated with the application of acetic acid and iodine to the vagina during the colposcopic procedure. Furthermore, another study on local anaesthesia of genital mucosa with a lidocaine/prilocaine combination cream in laser treatment of human papillomavirus lesions suggested that an application time of 5–15 minutes would be optimal.4 Our previous experience on topical lignocaine gel in pain relief for first-trimester therapeutic abortion had demonstrated a benefit of such treatment in minor gynaecological procedure.5 We would like to investigate whether such treatment also benefits women undergoing colposcopic assessment and biopsy.
As previous conflicting results may also be related to the dosage and duration of administration, we would like to investigate whether our proposed topical lignocaine gel application would relieve pain from cervical punch biopsy and alleviate the stinging sensation from application of acetic acid and Lugol’s iodine to the cervix and vagina.
Materials and methods
This is a randomised, double-blind placebo-controlled trial conducted in an accredited colposcopy service centre in Hong Kong. Women who attended the Cervical Disease Clinic of the Family Planning Association for colposcopy and biopsy after abnormal cervical cytology were recruited. Those who had taken analgesics in the previous 24 hours, had history of allergy to local anaesthetics and those with partial or complete heart block or with advanced liver disease or severe renal dysfunction were excluded. If cervical biopsy were not taken due to normal colposcopic examination, the women would be excluded after the recruitment.
One nurse interviewed the suitable subjects to explain the purpose of our study and to obtain their informed consent. The study protocol and consent form were approved by the Ethics Panel and the Health Services Subcommittee of the Family Planning Association of Hong Kong. A minimal sample size of 33 on each arm would have a 90% power to detect a true difference of two out of ten points in the mean pain score between the two treatment groups, using the SD of 2.5, as shown in the study by Church et al.3 We believed that a 2-point difference on a 10-point pain scale would be clinically meaningful. To make up for potential exclusion after recruitment, a sample of 45 on each arm was employed.
The recruited women were randomly assigned to the treatment group and the placebo group. The randomisation schedule was generated by the computer using blocks of ten. The name of the medication that would be used was sealed in a numbered opaque envelope. Each woman was given the medication in the envelope bearing the number she was assigned.
The nurse first enquired about the patients’ anticipated pain score for the whole procedure. Then, she passed a medium size speculum into the vagina and the baseline pain score was recorded. Five millilitres of 2% xylocaine jelly (Xylocaine Jelly®; AstraZeneca, Karlskoga, Sweden) or KY jelly (KY jelly®; Johnson & Johnson, Sezanne, France) was then applied to the cervix and upper part of the vagina through a syringe with extended tube. The women were asked to rest on the couch for 5 minutes after the application of gel and were then allowed to be ambulatory. Both the patient and the colposcopist were blinded on the nature of the jelly applied. After 10–15 minutes, the colposcopic procedure would begin. Pain score was rated using a visual analogue scale from 1 to 10 (1 = no pain, 10 = intolerable pain). Pain score was obtained at several points of the procedure: during the passage of speculum by the colposcopists, after the application of 3% acetic acid, after the application of Lugol’s iodine and after cervical punch biopsy. The number of cervical punch biopsies performed would be recorded, and the basic demographic and medical information, including age, education level, smoking habit, parity, previous cervical procedure and dysmenorrhoea were obtained from the medical notes. The need for additional analgesics after the procedure was also noted. Before the women left the clinic, they were asked about their overall pain score for the whole procedure.
Statistical analysis was performed using Statistical Program for Social Sciences (SPSS Inc., version 11.5, Chicago, IL, USA). T test was used to compare means for parametric continuous variables, while chi-square test was used for categorical data. Kruskal–Wallis test was used for comparing related categorical data. Mann–Whitney U test was used to compare means for nonparametric values. Spearman correlation test was used to assess the relationship of the basic demographic factors, application–procedure interval and number of biopsy on pain score. The mean anticipated and overall pain score was compared using Wilcoxon signed-ranks test.
Ninety women were recruited for the study. Nine of them were excluded from analysis as two of them had passed urine after the application of gel. It would be difficult to assess the amount of gel that might be repelled during urination that in turn affect the proper assessment of our proposed volume of gel used and the application time. There was difficulty in exposing the cervix of a woman for colposcopic assessment and so additional instrument was used. The other six women had additional procedures carried out other than colposcopy and biopsy that might have incurred additional pain (four had cervical polyp removed and two had endometrial sampling performed). Therefore, only 81 sets of data were included for analysis.
There was no statistically significant difference between the treatment and the placebo group in terms of their age, parity, education, dysmenorrhoea, smoking habit and previous cervical procedures. Table 1 showed the mean pain scores of the treatment and placebo groups. The baseline pain score (i.e. during the insertion of medium size speculum by nurse) was significantly higher in the treatment group than in the placebo group. There was no statistically significant difference in pain scores between the two groups in terms of anticipated and overall pain score, pain scores during insertion of speculum by colposcopists, application of acetic acid and Lugol’s iodine and pain during cervical and/or vaginal biopsy. The mean overall pain score of the colposcopy and biopsy procedure was significantly lower than the mean anticipated pain of the whole procedure by the subjects (P < 0.001). There was also no difference between the treatment and placebo arms in the application–procedure interval, the number of cervical biopsies, the vaginal biopsy performed and the need for additional analgesics.
Table 1. Pain scores at different time-point of the procedure and other procedure-related parameters
|Anticipated pain score||5.83 ± 1.38||5.31 ± 1.3||0.087*|
|Baseline pain score (insertion of medium size speculum by nurse)||2.19 ± 1.8||1.36 ± 1.77||0.014*,**|
|Pain score during insertion of speculum by colposcopist||1.48 ± 1.61||1.62 ± 1.79||0.784*|
|Pain score during the application of acetic acid||2.12 ± 1.99||2.05 ± 1.81||0.992*|
|Pain score during the application of Lugol’s iodine||2.43 ± 2.11||2.05 ± 1.73||0.561*|
|Pain score at biopsy||4.33 ± 2.63||3.90 ± 2.23||0.489*|
|Overall pain score||4.05 ± 2.45||3.87 ± 2.19||0.749*|
|Application of gel to procedure interval (minutes)||14.95 ± 4.88||14.69 ± 3.47||0.761*|
|Need of additional analgesics, n (%)||1 (2.6)||0 (0)||0.481***|
|Number of cervical biopsy||3.36 ± 0.69||3.41 ± 0.72||0.807*|
|Vaginal biopsy, n (%)||8 (19)||5 (12.8)||0.446***|
Spearman correlation test suggests that there was association between the application–procedure intervals with the pain score upon applications of acetic acid (P = 0.037) but not pain scores at other points. The number of cervical biopsies correlated with the pain during biopsy (P = 0.023) but not the overall pain score (P = 0.052). Vaginal biopsy was not associated with increased pain for biopsy and overall pain score. The overall pain score correlated with anticipated pain score (P = 0.001) and baseline pain score (P = 0.013) but not with the demographic factors of the subjects. However, the anticipated pain score was related to the severity of dysmenorrhoea of the subjects (P = 0.008).
Women perceived colposcopy and biopsy as a slightly painful procedure as reflected in the mean perceived pain score of 5.5 over a 10-point score in visual analogue scale in our study. Studies have previously been conducted in pain control for colposcopy and biopsy but yielded conflicting and discouraging results. One study6 reported the use of submucosal injection of topical anaesthetics before biopsy with promising pain relieving results. However, submucosal injection of local anaesthetics will give rise to bleeding and may interfere with the view for proper biopsy of suspected lesions. It also cannot relief the discomfort associated with the applications of acetic acid and Lugol’s iodine. The use of topical anaesthetic gel will not interfere with colposcopic assessment and biopsy as the gel can be easily removed during saline wash. The application of larger amount of anaesthetic gel at cervix and upper vagina can theoretically enhance the anaesthetic effect and provide additional protection against the stinging sensation or pain associated with the use of acetic acid and Lugol’s iodine and even for vaginal biopsy. The use of vaginal applicator is a convenient means to deliver the anaesthetic gel. However, women in Hong Kong are not used to self-administration of medication using vaginal applicator. The amount of gel that can be applied directly to the cervix and upper part of vagina may vary among different subjects. Therefore, in our study, we employed the same nurse to apply gel to women to minimise the variation in application. The passage of medium size speculum during the application of gel can also serve to assess baseline pain score of individuals.
Our study did not find any significant difference in pain scores among women treated with topical xylocaine gel versus those treated with KY jelly. However, the baseline pain scores of the two groups were different despite randomisation. If one believe that the baseline pain score reflects an individual’s pain threshold, the use of xylocaine gel would be beneficial to this group of women with lower pain threshold as it equalised the overall pain score with the other group women with higher pain threshold.
One would suspect that the lack of difference in pain scores could be related to the insufficient time for the onset of action of the topical xylocaine gel. According to Monthly Index of Medical Specialities annual (17th edition), anaesthetic effect of the gel usually occurs rapidly within 5 minutes and lasts for 20–30 minutes. However, we found no correlation between the duration of application of gel to onset of procedure with various pain scores, except the pain score associated with application of acetic acid. Future studies can be conducted to assess how the application–procedure interval can affect the various pain scores and to find out the optimal time for application.
It is interesting to note that although the number of biopsies affected the pain score associated with biopsy, it was not related to the overall pain score. This reflects that pain associated with biopsy is only short term. It was not possible to assess the effect of topical xylocaine gel on pain associated with vaginal biopsy, as the number was so few. Therefore, it would not be surprising that vaginal biopsy did not affect the overall pain score. There was only one woman in the treatment group who required additional analgesics. However, the provision of the additional analgesics was after the scoring of the overall pain score. Therefore, the overall pain score would not have been affected by the use of additional analgesics.
The overall pain score was, however, associated with the anticipated pain score. Anticipated pain score was affected by the severity of dysmenorrhoea. Women who are constantly disturbed by painful periods might have the false impression that procedures related to genital organs are always painful. Future intervention trials involving educational talk prior to colposcopy appointment can be used to assess whether correct information can help to improve the anticipated and overall pain score related to the procedure for this group of women. In the meantime, xylocaine gel can be used in the subgroup of women with unpleasant experience with prior speculum examination to alleviate their adverse response to colposcopy and biopsy.
Contribution to authorship
C.Y.G.W. originated the idea of the study, wrote the study protocol, designed the electronic database, analysed and interpreted the data and wrote up the manuscripts. C.Y.G.W., R.H.W.L. and T.S.W. were the colposcopists involved in the study. R.H.W.L. also contributed to data analysis and interpretation. C.Y.G.W., R.H.W.L., T.S.W. and S.Y.S.F. contributed to the design, analysis and revising of the manuscript.
Details of ethics approval
The Ethics Panel and the Health Services Subcommittee of the Family Planning Association of Hong Kong approved the study on 26 July 2006.
The authors would like to thank RN Carmen Lai who is the nursing in-charge of the Cervical Disease Clinic of the Family Planning Association of Hong Kong for her effort in recruitment, assessment of baseline pain score, applying the gel and managing the data.