A Comparison of Pain Perception Using Topical EMLA Cream Versus Lidocaine Injection for Vulvar Biopsy: a Randomized Controlled Trial
Phase: PHASE4
Conditions: Any Condition Requiring Vulvar Biopsy
Sponsor: Duke University

Study Protocol 
A comparison of pain perception using topical EMLA cream versus lidocaine injection for vulvar 
biopsy: a randomized controlled trial 
NCT03654417 
Study Protocol approved September 23, 2019 
 
 

Research Abstract 
 
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.  
 
Subjects recruited from the Duke Gynecology Oncology clinic and the Duke Womens Cancer Care 
Raleigh clinic who will be receiving a vulvar biopsy will be randomized to receive either EMLA cream or 
injectable lidocaine in preparation for the biopsy. Subjects will complete a baseline survey, and 
sociodemographic information will be collected. Pain will be assessed using a 100 mm visual analog 
scale: at baseline, after application of EMLA or lidocaine injection, and immediately after vulvar biopsy. 
Subjects will then complete an exit survey on their perception of the tolerability and acceptability of the 
procedures. The primary outcome is highest subjective pain score. 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. Subjects will be compensated $20 for their participation. 
 
We chose a 16-mm difference on a standard 100-mm visual analog pain scale as value of clinical 
significance. In order to detect at least a 16-mm difference with 90% power and alpha of .05, we 
estimated a total sample size of 53. Highest mean pain scores between anesthetic methods will be 
compared as the primary outcome using T-test vs Wilcoxon Rank sum test. Patient perception of 
tolerability and acceptability of the procedure as well as the provider’s satisfaction with the procedure 
will also be analyzed. There are no additional risks/benefits to the study participant for being part of the 
study as both methods of anesthesia are considered standards of care. 
 
Primary Objectives 
 
To compare highest subjective pain score with application of EMLA cream versus injection of lidocaine 
for analgesia for vulvar biopsy. 
 
Secondary Objectives 
 
To compare pain scores at vulvar biopsy 
To investigate possible pathologic changes associated with EMLA cream administration 
 

Purpose 
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. 
 
Background and Significance 
 
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. 
  
There have been case reports of EMLA induced pathologic changes in children with a variety of 
inflammatory skin conditions where disruptive changes on H&E were noted.  Similarly in a small series of 
patients with vulvar dermatoses, EMLA was associated with similar disruptive changes on H&E. The 
extent of these changes and their ability to impact pathologic diagnoses have not been studied. 
 
Design and Procedures 
 
Following informed consent enrollment, subjects will be randomized to an arm of the study using the 
randomization tool in REDCap. eConsent will be programmed in REDcapand. Study subjects, study staff, 
and performing providers will not be blinded to the intervention as the interventions are different; 
therefore, our study design is an unblinded randomized controlled trial.Selection criteria are listed in the 
table below. 
  
Selection Criteria 
Participant Inclusion Criteria 
Participant Exclusion Criteria 
• 
Females above age 18 presenting to 
Duke Gynecology Oncology clinic for 
vulvar biopsy 
• 
Able to provide informed consent in 
English and agree to the risks of the 
study 
a. Not able to provide informed 
consent 
b. Vulvar biopsy on a hair bearing 
surface 
It is not standard to perform pregnancy testing prior to vulvar biopsy in Duke Gynecology Oncology clinic 
and Duke Womens Cancer Care Raleigh clinic as the administration of anesthesia and procedure itself 
present minimal risk of harming a fetus.   Both EMLA cream and injected lidocaine are labeled pregnancy 
category B indicating that reproduction studies performed in rats have revealed no evidence of harm to 

the fetus, but there are no adequate and well-controlled studies in pregnant women (10, 14).  For these 
reasons, we will not perform pregnancy tests on possible study participants. 
  
Because participation in the study only lasts the duration of the clinic visit during that day, and EMLA 
and lidocaine are pregnancy category B, there are no specific contraceptive methods required preceding 
or following participation in the study.  
  
Measurement of anxiety, acceptability, and pain 
Before the procedure is performed, subjects will complete the GAD-7, a validated 7 item anxiety 
disorder scale(15). 
  
Subjects will report pain using a visual analog scale, a scale comprised of a 100 mm horizontal line 
anchored with 2 verbal descriptors, one for each symptom extreme.For pain, the scale is most often 
anchored by “no pain” (score of 0) and “worst imaginable pain” (score of 100 mm). The patient marks 
their pain with a vertical line perpendicular to the scale, and the distance from 0 is measured with a 
ruler (16-18). 
  
Subjects will also be asked to rate the overall acceptability and tolerability of the procedure performed 
with a visual analog scale.The provider performing the biopsy will rate their overall satisfaction and 
perception of patient tolerability of the procedure using the same scale.The subjects will also be asked if 
the procedure was better or worse than they expected. 
  
Study Procedures: 
Intake information: Patients will present to their scheduled Duke Gynecology Oncology Clinic or Duke 
Womens Cancer Care Raleigh clinic appointment.  If it is determined that a vulvar biopsy is indicated, the 
provider will briefly inquire about interest in the study.  If interested, a study coordinator will introduce 
the study to the patient and perform informed consent should they decide to participate.  After 
providing informed consent, the patient will complete a survey including sociodemographic information 
and a baseline anxiety survey (GAD7) (see appendices).  The following information will be collected: age, 
race, ethnicity, level of education, baseline vulvar pain using a 100 mm visual analog scale, history of 
previous vulvar biopsy, daily narcotic or anxiolytic use.  Information including BMI, chronic pain 
diagnoses, history of vulvar cancer will be collected by study coordinators from the medical record.  
  
Participants will complete questionnaires electronically with the exception of the pain assessment by 
visual analog scale.The data will be collected directly into REDCap.Pain scores will be entered into 
REDCap by measuring from 0 millimeters the hash mark made by the patient.There will be paper forms 
of the questionnaires available, as a secondary option should it become necessary. 

  
Randomization: After completing the entry intake information, the subject will be randomized to EMLA 
cream application or lidocaine injection using the randomization tool within REDCap 
  
Procedure: The subject will then be placed in dorsal lithotomy position on the Gynecology Oncology 
pelvic exam tables in preparation for the procedure.   If the patient is randomized to the EMLA cream 
group, the EMLA cream will be applied at the intended site of biopsy and left in place for a minimum of 
10 minutes prior to biopsy.  Approximately 5 g of EMLA should be applied in a thick layer to the area to 
be biopsied (a 1g strip is approximately 1.5 x 0.2 inches and squeezed from the tube in a narrow strip) 
(10).  The subject will report a pain score at time of EMLA application.  After 10 minutes vulvar biopsy 
will be performed.  
  
For subjects receiving lidocaine injection, approximately 2 mL of 1% lidocaine will be injected 
superficially at the planned biopsy site using a 25- or 27-gauge needle at the discretion of the 
physican.The subject will report pain at time of injection on a 100 mm visual analog scale before 
proceeding to vulvar biopsy. The provider will then wait at least one minute after lidocaine injection 
before performing the biopsy. 
  
In both arms, should the provider deem anesthesia to be inadequate prior to performance of the biopsy, 
an additional lidocaine injection will be allowed prior to biopsy and this will be recorded. 
  
Vulvar biopsies will be performed using standard biopsy forceps or a punch biopsy (3-4 mm) device 
depending on provider preference.The subject will report pain using a 100 mm visual analog scale 
immediately following biopsy. 
  
If there are multiple biopsy sites that are treated, and the pain differs between these locations, the 
highest pain score will be recorded. 
  
If the procedure is interrupted secondary to pain, a pain score will be recorded prior to injecting 
additional lidocaine, as described above. 
  
Exit Survey: After completion of the procedure, subjects will complete an exit survey, as described 
above(see appendices), answering questions about overall satisfaction/tolerability of the procedure. 
  

The provider performing the biopsy will also complete a brief survey answering questions about their 
satisfaction with the procedure and their perception of the acceptability of the procedure performed. 
  
As described above, participants will complete questionnaires electronically with the exception of the 
pain assessment by visual analog scale, which will be completed on paper and measured distances will 
be entered into REDCap. 
  
Participants will receive a $20 check for participation in the study.All completed surveys will be collected 
by the study coordinator who will store the documents in a password protected file on the Duke secured 
server. 
  
Post Study Pathologic Analysis: To address the concern that EMLA might induce pathologic changes that 
could result in altered diagnosis, pathologist independent from initial diagnostic read will re-evaluate 
tissue slides and look for the previously described EMLA induced pathologic changes (pallor, necrosis, 
spongiosis, basophilic granules, acantholysis, clefting, papillary dermal edema).  Pathologist will be 
blinded to whether or not patient received EMLA cream for biopsy.  They will provide a score for all 
specimens that will be used to analyse any pathologic differences between patients exposed to EMLA 
and those not exposed to EMLA.   
 
Selection of Subjects 
 
An electronic consent form will be used during the informed consent process, the signed copy of the 
study consent form will be emailed to the subject or printed and provided to her in clinic based on her 
preference. Subjects will then be assigned a unique subject number by the research coordinator. 
Research coordinators will maintain an enrollment log to serve as the master list for the enrolled 
subjects.  After their information is placed into the enrollment log, the subject will only be identified by 
their unique number.  The enrollment log as well as the study questionnaires and pain assessment forms 
will be collected into a REDCap data base with any exported copies saved in a password protected file on 
the Duke secured server. 
 
Subject’s Capacity to Give Legally Effective Consent 
 
Subjects who do not have capacity to give legally effective consent will not be included in the study. 
 
Risk/Benefit Assessment 

There is a potential benefit for the subjects in this study in that they may receive analgesia for the 
procedure without the pain of an injection.However, it will be emphasized to the subject that there may 
be increased pain during biopsy in the EMLA arm or increased pain with injection for the lidocaine arm. 
  
There are risks associated with vulvar biopsy including bleeding and infection.These risks are small, but 
they are not risks incurred as a result of participating in the study as these patients will be getting vulvar 
biopsies regardless of study participation. 
  
There is a small risk of topical reaction to the EMLA cream.If irritation does occur, the area of irritation 
will be cleansed with water and the procedure will be postponed until the irritation is resolved.The 
subjects will return to clinic to assess for resolution of the area and their indicated vulvar biopsy. 
 
Costs to the Subject 
 
No additional costs will be incurred by the participant as a result of participating in this study 
 
Data Analysis and Statistical Considerations 
 
A 16-mm difference on a standard 100-mm visual analog pain scale was deemed clinically significant. In 
order to detect a 16-mm difference with 90% power at an alpha level of 0.05 assuming a standard 
deviation of 25-mm, we estimated a needed sample size of 53 participants in each treatment arm. 
However, due to time limitations, data collection will end on March 12, 2019. Only patients consented 
on or prior to March 12, 2019 will be included in the study. Data will be recorded using Research 
Electronic Data Capture (REDCap), and the database will be locked on March 13, 2019. Pain will be 
measured during the application of EMLA cream or lidocaine injection, and immediately after biopsy. 
The primary outcome will be the highest pain score recorded during the procedure. The primary 
outcome will be compared between treatment arms using linear regression adjusting for baseline pain. 
Secondary outcomes include pain score at vulvar biopsy, patient tolerability and acceptability, and 
provider’s satisfaction with the procedure. All testing will be performed at a two-tailed significance level 
of 0.05.  
 
 If significance for the primary objective is not achieved, then patient accrual will continue based on a 
new sample size determined by the primary results of this analysis. This will be the number of new 
patients that need to be enrolled. Outcomes will be assessed again at the point when the final sample 
size is achieved.