Buffered Lidocaine for Loop Electrosurgical Excision Procedures (LEEPs)

This study has been completed.
Information provided by (Responsible Party):
Washington University School of Medicine
ClinicalTrials.gov Identifier:
First received: July 28, 2011
Last updated: July 12, 2013
Last verified: July 2013

Women undergoing a LEEP procedure who receive lidocaine buffered with sodium bicarbonate for their cervical block will experience less injection pain than women who receive plain lidocaine.

Condition Intervention Phase
Uterine Cervical Dysplasia
Drug: sodium bicarbonate buffered lidocaine
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator, Outcomes Assessor)
Primary Purpose: Supportive Care
Official Title: A Randomized Trial of Buffered vs Nonbuffered Lidocaine With Epinephrine for Cervical Loop Excision

Resource links provided by NLM:

Further study details as provided by Washington University School of Medicine:

Primary Outcome Measures:
  • Injection Pain Score [ Time Frame: immediately following procedure ] [ Designated as safety issue: No ]
    A Likert visual analog scale will be used to document each study participant's level of pain experienced during injection of the cervical block.

Secondary Outcome Measures:
  • Overall LEEP procedure pain (including procedural pain and cramping) [ Time Frame: immmediately following procedure ] [ Designated as safety issue: No ]
    A likert visual analog scale will be used to determine the overall pain experienced by each study participant including injection pain, procedural pain, and cramping.

Enrollment: 55
Study Start Date: July 2011
Study Completion Date: December 2012
Primary Completion Date: October 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
No Intervention: Lidocaine Arm
Women in this arm will receive plain lidocaine with epinephrine injected into their cervix prior to the LEEP procedure.
Experimental: Buffered Lidocaine
Women in this arm will receive sodium bicarbonate buffered lidocaine mixed with epinephrine injected into their cervix prior to the LEEP procedure.
Drug: sodium bicarbonate buffered lidocaine
8.4% sodium bicarbonate will be mixed with lidocaine in a 1:10 ratio prior to mixing with epinephrine and injecting into the cervix.

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Detailed Description:

Specific aims:

  1. To determine whether buffering the agent used for intracervical anesthetic at the time of cervical loop excision reduces injection-related pain. (Hypothesis: buffering significantly reduces injection-related pain.)
  2. To determine whether other components of pain from LEEP (procedural pain, and cramping) can be reduced by buffering of intracervical anesthetic among women undergoing cervical loop excision. (Hypothesis: only injection pain will be reduced by buffering, as procedural pain will be reduced by lidocaine equally in both arms and cramping will not be reduced in either arm.)


Although cervical cancer rates have been dramatically reduced by Pap test screening and the eradication of precursors, more than 100,000 U.S. women develop premalignant cervical lesions each year that require treatment (1). The cervical loop electrosurgical excision procedure (LEEP) is the most common therapy for CIN among U.S. gynecologists. LEEP is performed using one or more 1-2 cm electrosurgical diathermy loops to excise involved and at-risk cervical epithelium including underlying stroma containing glands. Destroying this tissue eliminates cells infected with human papillomavirus, the proximate cause of cervical cancer, and radically reduces the risk of later developing cervical cancer (2, 3).

LEEP is usually performed as an outpatient procedure using intracervical anesthesia, most commonly combining lidocaine as an anesthetic agent with epinephrine as a hemostatic agent; final hemostasis is achieved using electrosurgical fulguration and topical hemostatic agents (4). Prior literature has suggested that pain from LEEP has 3 components: pain from injection of the anesthetic combination, pain from the excision, and cramping from reflex uterine contractions (5). While cramping can be controlled with oral nonsteroidal anti-inflammatory agents, injection and procedural pain are not. Most women categorize the pain of LEEP as 3-7 on a 0-10 Likert scale (5, 6).

Studies of dermal and ocular anesthesia and bone marrow biopsy have found that buffering of acidic local anesthetic agents reduces injection pain (7-14), with up to 66% reduction in pain and significant results in randomized trials involving 30-50 participants. However, the use of buffered lidocaine has not yet been tested for LEEPs. The principal investigator has used both forms of anesthesia and considers both acceptable forms of therapy; he is unaware of any evidence to support the superiority of either arm.

Inclusion criteria 1. Subjects ≥ 18 years who meet any of the following indications for LEEP:

a. Antecedent biopsy read as i. cervical intraepithelial neoplasia (CIN) grade 2 or 3 or microinvasive cancer ii. adenocarcinoma in situ iii. persistent CIN1 b. Antecedent Pap read as i. high grade squamous intraepithelial lesion ii. atypical glandular cells iii. persistent low grade squamous intraepithelial lesion Exclusion criteria

  1. Anatomy unsuitable for safe office loop excision based on operator judgment
  2. Inability to tolerate procedure under local anesthesia
  3. Pregnancy
  4. Age less than 18 years
  5. Inability to understand spoken or written English
  6. Refusal of consent
  7. Prisoner
  8. Mental incapacity
  9. Anticoagulant or antiplatelet therapy, or known bleeding diathesis
  10. Use of analgesics other than over the counter medications (OTC meds include NSAIDS or Tylenol) within 7 days of scheduled LEEP

Methods Eligible, consenting women who have either a negative pregnancy test or are postmenopausal women who present for LEEP in the Gynecologic Treatment Center in the Center for Advanced Medicine will be randomized to either buffered or nonbuffered lidocaine. The LEEP clinic is run by the PI, Dr. Leslie Massad, and as such this is the PI's patient population and clinic. Women will be asked about analgesics and antiplatelet or anticoagulant therapy, and records will be reviewed for a history of bleeding diathesis. Subjects will not be excluded for use of over the counter medications such as Ibuprofen or Tylenol. Subjects who have taken stronger prescription analgesics (ie codeine, or other narcotics) within 7 days of her scheduled LEEP procedure will be excluded.

Randomization will be by computerized random number generation by the Division of Clinical Research in the Department of Obstetrics & Gynecology at Washington University in St. Louis. Treatment assignments will be sequenced accordingly, and prepared, opaque envelopes will be opened in order by either the medical assistant (MA) or registered nurse (RN) responsible; neither the MA or the RN will perform the procedure or obtain pain scores. Only the RNs will prepare the study drug solution.

The randomization envelopes will be prepared by Dr. Peipert's team and, then will be submitted sealed to the LEEP clinic where they will be stored by the MAs. Only the MAs and the RNs will have access to these envelopes. Once randomization of the participant is noted by one of two gynecologic oncology RNs (Gina Vansickle, RN or Vanessa Thomas-Homes, RN), she will then fill syringes with either 10 ml 1% lidocaine with epinephrine 1:100,000 (control) vs 9 ml 1% lidocaine with epinephrine 1:100,000 and 1 ml of a 1mEq/ml (8.4%) solution of NaHCO3 (study) in a separate room adjacent to the LEEP procedure room. The RNs will prepare the anesthesia solution as if in standard clinical practice. Anesthetic will be carried immediately to the treatment area, so storage will not occur. Neither the treating clinicians performing LEEP nor the patient will be informed of allocation. Either the MA or RN will inform the study coordinator (Lynne Lippmann) of the treatment allocation once the participant has completed the post-procedure questionnaire and she is finished with her participation in the study. The principal investigator along with all members of the study team involved in data analysis will remained blinded to the study groups until the analyses are fully completed.

After informed consent for procedure and study, and after cervical visualization as per standard clinical care to determine suitable cervical anatomy for excision, the anesthetic solution will be injected intracervically. The injection technique will not differ from routine practice and will be done within 30 minutes of mixing the solution. The patient will be advised that pain experienced at this point is "injection pain." LEEP will be tailored to individual needs according to lesion size, lesion grade, and depth into the endocervical canal. Once the procedure begins, the patient will be informed that the subsequent cramping pain is distinct from the pain felt at the time of injection and is considered "procedural" pain.

Within 30 min of completion of the procedure and after instruction by the primary investigator, women will represent the intensity of their pain by marking single lines across 100mm Likert visual analog scales employed in prior nongynecologic studies of buffered lidocaine (5, 7-10) (See appendix). Scales will not include hashmarks or internal descriptors, as these have been shown to bias responses and diminish reliability (12). Separate scales will be marked to represent the previously identified domains of intensity of pain from injection, pain from LEEP, and cramping (3). Buffering will be assumed to have influenced pain for any of the three domains with a significant reduction in pain score. Self-designated ethnicity will be solicited to facilitate description of the study population to allow for generalization of results. This information will be obtained as part of the pain assessment questionnaire given to the participant post-procedure (See appendix).

Patient participation in the study will end on completion of the pain scoresheet. Clinical follow-up will continue as per usual standard care. The principal investigator will review charts for additional demographic information and procedural data, again to allow for generalization of results.

Risks No serious risks are likely. Less likely risks may include greater pain from a diluted lidocaine solution, though this has not been seen with buffered lidocaine used for other procedures, and increased bleeding from dilution of the epinephrine in the anesthetic solution. Alkalinization of epinephrine-containing local anesthetic solutions takes several hours; since buffered lidocaine with epinephrine will be injected within 30 min of mixing, this should not be relevant to the current study (13).

Statistical analysis Patient marks on 100mm Likert scale lines will be measured by the PI and a score defined by the length marked off in mm. We will first perform basic descriptive statistics on the baseline data of the two groups. We will then assess whether the randomization achieved balance of baseline characteristics using standard chi-square and Fisher Exact tests (for categorical variables), and t-tests or nonparametric tests for continuous data. We expect the pain scores will not approximate a Gaussian distribution, so we will use a Mann-Whitney non-parametric test to compare pain scores of the two groups. Assuming an alpha (type I error rate) of 0.05, a power of 80% (type II error rate of 0.20), a pain score of at least 5 for 80% of women in the standard treatment arm, and a 50% reduction in pain with buffering to 40% scoring pain above 5, with no loss to follow-up, 27 women will need to be accrued per group, or 54 women in the trial. This should be achievable within 2 years.


When a patient is found to be eligible for study, verbal and signed informed consent will be required by the managing physician. Nora Kizer, MD, physician and study team member, will contact the potential study participant by telephone to discuss the research project, evaluate eligibility criteria, and answer any questions. Information included in the consent form will be discussed. However, the potential participant will not view the actual consent document until the day of her scheduled LEEP. There will be an approximate 1-2 week wait period between the phone conversation and the date of the LEEP where the patient may discuss with study with family and friends, if desired. Individuals who agree to participate by phone, will be asked to sign a consent document in clinic at the time of their regularly scheduled LEEP. A paper copy of the consent form will be mailed to those individuals who agree to participate or remain undecided after the telephone conversation. The potential participant may to decline to participate at that time, even if she initially agreed to participate over the phone. An eligibility checklist will be submitted to the Contact Person/Data Manager at Washington University, Lynne Lippmann (FAX # 314-362-2893). Questions concerning eligibility may be addressed to the Study Chair(s), Contact Person, or Data Manager. A protocol number will be assigned and the designated study team member (Dr. Nora Kizer) will be informed of this number. All patient entries will also be reported to the Siteman Cancer Center by the Gynecologic Oncology Data Manager for entry into their database. The following forms will be completed in a timely fashion as per the schedule below and will be placed in the subject's study chart: Eligibility checklist, datasheet, patient scoresheet, consent.

Data Safety and Monitoring The principal investigator will supervise or perform all LEEPs. A separate research member (Dr. Nora Kizer) will complete all data entry sheets (including measurement of Likert scores and description of adverse events), and will enter de-identified data to a spreadsheet.

The frequency and severity of all toxicities will be tabulated on an ongoing basis and summarized for review under the Data Safety and Monitoring Plan for this study (DSMP) as per the guidelines for the Siteman Cancer Center at Washington University. Data for this study will be reviewed by L. Stewart Massad, M.D. (Gynecologic Oncology), Nora Kizer, M.D. (Gynecologic Oncology), and Lynne Lippmann, CCRP (Research Administrator) (Gynecologic Oncology). Statistical support will be provided by Jeffery Peipert, MD, MPH, MHA and Feng Gao, MD, PhD. Data will be reviewed every six months for toxicities and response, prior to the bi-annual report to the Quality Assurance and Safety Monitoring committee of the Siteman Cancer Center. All serious and/or unexpected events will be communicated to the Study Chair and reviewed within 2 working days for consideration of notification, amendment, or immediate study suspension.

The principal investigator will review all patient data at least every six months, and provide a semi-annual report to the Siteman Cancer Center Quality Assurance and Safety Monitoring (QASM) Committee. This report will include

  1. The protocol title, IRB protocol number, and the activation date of the study.
  2. The number of patients enrolled to date
  3. The date of first and most recent patient enrollment
  4. A summary of all adverse events regardless of grade and attribution
  5. A response evaluation for evaluable patients
  6. A summary of any recent literature that may affect the ethics of the study Privacy will be protected by storing all records and the master list in a locked office (Dr. Kizer); all computerized records will be stored on a password-protected computer with backup on a flash drive stored in a locked cabinet in the same locked office.

Study Calendar Study Phase Recruitment Consent Research Participation Follow-up Time Frame 2 weeks prior to scheduled LEEP Day of LEEP Day of LEEP N/A Activity 1 Patient is called to discuss their potential participation in the study and review consent form. On day of procedure, the consent form is reviewed with the patient and signed. The participant undergoes LEEP in routine fashion. She receives either buffered or plain lidocaine for anesthesia. There is no follow-up specific to the study. Each patient will follow-up per routine clinical practice.

Activity 2 Paper copy of consent form is mailed. All questions and concerns are addressed. Post-procedure questionnaire is completed by the participant.


  1. Henk HJ, Insinga RP, Singhal PK, Darkow T. Incidence and costs of cervical intraepithelial neoplasia in a US commercially insured population. J L Gen Tract Dis 2010; 14(1): 29-36.
  2. Gustafsson L, Ponten J, Zack M, Adami H-O. International incidence rates of invasive cervical cancer after introduction of cytological screening. Cancer Causes Ctrl 1997; 8: 755-763.
  3. Herbert A, Anshu, Gregory M, Gupta SS, Singh N. Screen-detected invasive cervical carcinoma and its clinical significance during the introduction of organized screening. BJOG 2009; 116: 854-859.
  4. Herzog TJ, Williams S, Adler LM, Rader JS, Kubiniec RT, Camel HM, Mutch DG. Potential of cervical electrosurgical excision procedure for diagnosis and treatment of cervical intraepithelial neoplasia. Gynecol Oncol 1995;57:286-93
  5. Harper DM, Walstatter BS, Lofton BJ. Anesthetic blocks for loop electrosurgical excision procedure. J Fam Pract 1994;39:249-56.
  6. Lipscomb GH, McCord ML, Bain KW, Ling FW. The effect of topical 20% benzocaine on pain during loop electrosurgical excision of the cervix. Am J Obstet Gynecol 1995;173:772-4.
  7. Ruegg TA, Curran CR, Lamb T. Use of buffered lidocaine in bone marrow biopsies: a randomized, controlled trial. Oncol Nurs Forum 2009;36:52-60.
  8. Sharma T, Gopal L, Shanmugam MP, Bhende P, George J, Samanta TK, Mukesh BN. Comparison of pH-adjusted bupivacaine with a misture of non-pH-adjusted bupivacaine and lignocaine in primary vitreoretinal surgery. Retina 2002;22:202-7.
  9. Fitton AT, Ragbir M, Milling MA. The use of pH adjusted lignocaine in controlling operative pain in the day surgery unit: a prospective, randomized trial. Br J Plast Surg 1996;49:404-8.
  10. Burns CA, Ferris G, Feng C, Cooper JZ, Brown MD. Decreasing the pain of local anesthesia: a prospective, double-blind comparison of buffered, premixed 1% lidocaine with epinephrine versus 1% lidocaine freshly mixed with epinephrine. J Am Acad Dermatol 2006;54:128-31.
  11. Younis I, Bhutiani RP. Taking the 'ouch' out—effect of buffering commercial xylocaine on infiltration and procedure pain—a prospective, randomised double-blind controlled trial. Ann R Coll Surg Engl 2004;86:213-7.
  12. Masters JE. Randomised control trial of pH buffered lignocaine with adrenaline in outpatient operations. Br J Plast Surg 1998;51:385-7.
  13. Orlinsky M, Hudson C, Chan L, Deslauriers R. Pain comparison of unbuffered versus buffered lidocaine in local wound infiltration. J Emerg Med 1992;10:411-5.
  14. Scott J, Huskisson EC. Graphic representation of pain. Pain 1976;2:175-84.
  15. Robinson J, Fernando R, Sun Wai WY, Reynolds F. Chemical stability of bupivicaine, lidocaine and epinephrine in pH-adjusted solutions. Anesthesia 2000;55:853-8.

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • antecedent biopsy read as cervical intraepithelial neoplasia (CIN) grade 2 or 3 or microinvasive cancer, adenocarcinoma in situ, persistent CIN 1
  • antecedent pap read as high grade squamous intraepithelial lesion, atypical glandular cells, and persistent low grade squamous intraepithelial lesion

Exclusion Criteria:

  • anatomy unsuitable for safe office loop excision based on operator judgement
  • inability to tolerate procedure under local anesthesia
  • pregnancy
  • age less than 18 years
  • inability to understand spoken or written English
  • refusal of consent
  • prisoner
  • mental incapacity
  • anticoagulant or antiplatelet therapy, or known bleeding diathesis
  • use of analgesics other than over the counter medications within 7 days of scheduled LEEP
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01405768

United States, Missouri
Washington University School of Medicine
Saint Louis, Missouri, United States, 63110
Sponsors and Collaborators
Washington University School of Medicine
Principal Investigator: Leslie S Massad, M.D. Washington University School of Medicine
  More Information

Additional Information:
Responsible Party: Washington University School of Medicine
ClinicalTrials.gov Identifier: NCT01405768     History of Changes
Other Study ID Numbers: 201104269
Study First Received: July 28, 2011
Last Updated: July 12, 2013
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Uterine Cervical Dysplasia
Cervical Intraepithelial Neoplasia
Precancerous Conditions
Uterine Cervical Diseases
Uterine Diseases
Genital Diseases, Female
Carcinoma in Situ
Neoplasms, Glandular and Epithelial
Neoplasms by Histologic Type
Epinephryl borate
Adrenergic beta-Agonists
Adrenergic Agonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Pharmacologic Actions
Physiological Effects of Drugs
Bronchodilator Agents
Autonomic Agents
Peripheral Nervous System Agents
Anti-Asthmatic Agents
Respiratory System Agents
Therapeutic Uses
Adrenergic alpha-Agonists

ClinicalTrials.gov processed this record on July 20, 2014