A Prospective, Randomized Controlled, Single-Blinded Study to Assess the Effect of a 33-Gauge Needle Versus a 34-Gauge Needle on Pain Experienced During Injection of Local Anesthetic on the Face
November 2023 | Volume 22 | Issue 11 | 1124 | Copyright © November 2023
Published online October 30, 2023
Kourosh Beroukhim MDa,b, Paige H. Williams MDa,b, Leonard H. Goldberg MDa,b, Maria Sarah Bovenberg MD PhDa,b, Xin Tan BSc, Meng Li PhDc, Elizabeth Hall MDa,b, Isadore Tarantino MDa,b, Remi Hamel MDa,b
aDivision of Micrographic Surgery and Dermatologic Oncology, Houston Methodist Hospital, Houston, TX
bDermSurgery Associates, Houston, TX
cDepartment of Statistics, Rice University, Houston, TX
Abstract
Background: Most pain experienced by patients during Mohs micrographic surgery is associated with the initial injection. Previous studies have shown that a smaller gauge needle (33-gauge vs 30-gauge) is associated with less patient-reported pain.
Objectives: To evaluate patient-reported pain levels following injection with a 33-gauge versus a 34-gauge needle.
Methods: During this prospective, randomized, controlled, single-blinded study, 480 patients were randomized into a 33-gauge versus a 34-gauge needle group. Pain levels following needle insertion were recorded using the validated numerical rating scale (VNRS)-11 scale.
Results: Injection of local anesthetic with a 34-gauge needle is associated with significantly less pain compared to a 33-gauge needle across all subgroups (P=0.007, average pain level 0.49 [34-gauge group] vs 0.79 [33-gauge group] rated on a 0-10 pain scale). Females, first-time Mohs patients, patients under age 65, patients with basal cell carcinoma, and those with tumor locations on the nose experienced the most pain reduction with the use of a 34-gauge needle.
Limitations: This was a single-blinded study; thus, the injector was able to see which needle was being used. This knowledge could have subconsciously affected the angle, speed, or force used to insert the needle.
Conclusions: Injections with a 33-gauge and a 34-gauge needle are both tolerated well and associated with minimal pain. While the pain reduction associated with using a 34-gauge needle is statistically significant, the use of a 34-gauge needle may be most clinically relevant for certain patient subgroups.
J Drugs Dermatol. 2023;22(11): doi:10.36849/JDD.7689
BACKGROUND
The pain associated with penetration of the needle into the skin and the infiltration of the local anesthetic agent is often the only pain experienced by patients during outpatient procedures.1 Suggested methods used to minimize this pain include buffering with sodium bicarbonate, warming the lidocaine solution, injecting slowly, using finer needles, and altering the injection depth or angle. A prior study demonstrated that a significantly smaller proportion of patients experience pain with injection of local anesthetic using a 33-gauge needle compared to a 30-gauge needle.2 However, even when using a 33-gauge needle, close to 25% of patients still felt some level of pain with injection of local anesthetic to the face. It is possible this can be reduced further with the use of needles that are finer than 33 gauge. To date, there are no studies assessing whether there is a significant difference in pain experience with injection of local anesthesia on the face using a 33-gauge versus a 34-gauge needle.
