Any Condition Requiring Vulvar Biopsy Clinical Trial
Official title:
A Comparison of Pain Perception Using Topical EMLA Cream Versus Lidocaine Injection for Vulvar Biopsy: a Randomized Controlled Trial
The purpose of this study is to compare pain control during vulvar biopsy following either (1) application of EMLA (a eutectic mixture of local anesthetics lidocaine 2.5% and prilocaine 2.5%) cream or (2) injection of 1% lidocaine. We hypothesize that lidocaine will provide better biopsy analgesia, but the benefit will be offset by the pain of lidocaine injection compared to EMLA application, thus there will not be a significant difference in highest pain scores between the two groups.
Performing minor procedures in-office is essential to gynecologic practices. In-office
procedures allow for evaluation and diagnosis of a variety of conditions while avoiding the
expense, anesthesia, and time associated with the operating room. Pain and discomfort are
frequently associated with these procedures, and ensuring that the patient has the least
amount of discomfort is a priority. Very painful or uncomfortable procedures could
potentially discourage a patient from returning to clinic or receiving the follow up that
they may need. Psychological, physiologic, and social factors influence a patient's
experience of pain. Previous studies, though mostly related to first trimester abortion
procedures in the office, indicate that the procedure type, anxiety, depression, and general
anticipation of pain predict increased pain during in office gynecologic procedures (1-4). A
review by Ireland et al., found that a multimodal approach that includes patient counseling
with other techniques is most effective in achieving optimum pain control for procedures
(5,6).
Vulvar biopsies are associated with significant discomfort, and some form of anesthesia is
required. The current standard in our group is to inject local anesthesia prior to vulvar
biopsy. However, the injection itself is associated with its own level of pain that is not
insignificant, and for many, the anticipation of receiving an injection is anxiety provoking.
The use of topical anesthesia in lieu of injection or as pre-injection analgesia is variable.
Several previous studies have examined the use of topical anesthetics in the place of or in
addition to injected anesthesia. Drouault et al. compared EMLA cream alone to injected
lidocaine alone for pain relief in vulvar biopsy and found that pain associated with
administration of anesthesia was significantly less for EMLA cream, but better biopsy
analgesia was obtained with injected anesthesia. The study considered combined pain scores
for both groups for the overall procedure (anesthesia + biopsy), it comments that the
combined scores were lower for the EMLA group but failed to reach statistical significance.
The study ultimately concluded that EMLA is the less painful procedure to obtain anesthesia
and that it can be used as an alternative to injection for biopsies of the genital mucosa
(7). This prior study did not compare the highest pain score between groups. Consideration of
the highest pain score allows us to assess whether the injection of lidocaine could result in
causing more pain than the biopsy itself using EMLA cream alone for anesthesia. Further, the
study did not assess the subjects' or the providers' perception of the tolerability and
acceptability of performing the procedure using either method. This is an important factor in
any in office procedure
EMLA cream is the most extensively studied topical anesthetic. It is FDA approved for use as
a topical anesthetic on the genital mucous membranes for superficial, minor surgery. EMLA
cream requires between 7-10 minutes of absorption time on the genital mucosa for analgesic
effect, with variable duration of analgesia following, usually around 15-20 minutes (9).
There is a highly variable absorption rate for EMLA cream depending on the characteristics of
the epithelium upon which it is applied as well as the duration and surface area of cream
applied. On hair-bearing non-mucosal surfaces it can require 60 minutes of application time
to obtain analgesic affect (10). The vulvar area is unique in that it contains both mucosal
and non-mucosal and hair-bearing surfaces; this could greatly affect the absorption of EMLA
and therefore affect analgesia. For this reason, we will exclude from the study patients
requiring vulvar biopsy on hair bearing portion of the vulva.
Several previous studies have examined the use of topical anesthetics in the place of or in
addition to injected anesthesia. Drouault et al. compared EMLA cream to injected lidocaine as
described above. The study found that pain associated with administration of anesthesia was
significantly less for EMLA cream, but better biopsy analgesia was obtained with injected
anesthesia. However, there were some limitations to this study also noted above, that we plan
to expand and improve upon with the current study.
Zilbert and Lewandoswki studied pre-treatment with EMLA cream prior to anesthesia injection
and found that pain was decreased by 50% in patients pretreated compared to placebo prior to
lidocaine injection.
Van den Berg studied application of EMLA alone versus lidocaine injection alone in punch
biopsies and electrocoagulation of genital warts in men. The study found that in the punch
biopsy cohort that the total pain scores (application of EMLA + biopsy versus injection of
lidocaine + biopsy) were less for the EMLA group than the injected lidocaine group and the
difference was statistically significant (11).
With its FDA approval for use as a topical anesthetic on the genital mucous membranes for
superficial, minor surgery, it can be considered a standard of care to use EMLA for
anesthesia prior to biopsy as an alternative to injection of lidocaine (10)
As there are no studies that consider the subjects' or the providers' perception of the
acceptability or the tolerability of the procedure, this will be novel data for vulvar
biopsy. However, acceptability and tolerability have been assessed in other procedural
settings, such as in office endoscopic procedures, in which BS-11, a validated 11 point
scale, is used to assess pain, anxiety, acceptability, tolerability, and levels of other
procedure related symptoms (12-13).
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