Botulinum Toxin Injection Pain Is Less With Smaller ­Gauge Needles

NEW YORK (Reuters Health) ­- Injection of botulinum toxin type A through 32­gauge needles is slightly less painful than injection through 30­gauge needles, according to a randomized trial.

Dermatologists routinely use 30­gauge needles for facial injections of neurotoxins, prepackaged fillers, and intralesional local anesthesia, but pain is still an issue even with these small­gauge needles.

Dr. Murad Alam, from Feinberg School of Medicine, Northwestern University, Chicago, and colleagues compared discomfort associated with superficial cutaneous injections of botulinum toxin type A using 30­ and 32­gauge needles in a split­face randomized trial of 20 patients. They also compared the discomfort of saline injections into the upper arms using the two needles.

Mean injection pain scores for the face were nominally lower with the 32­gauge needle (3.41/10) than with the 30­ gauge needle (4.16/10). The mean pain scores were lower for the arm injections (1.21 with the 32­gauge needle and 1.66 with the 30­gauge needle).

Clinically significant pain was 3.8 times more likely with facial injections with 30­gauge needles than with 32­gauge needles (p=0.04), whereas there were no clinically significant differences in pain associated with needle type with arm injections, according to the September 9 JAMA Dermatology online report.

Pain descriptors (throbbing, shooting, stabbing, and so on) did not differ significantly between the needle types.

"This study is important because it suggests that for a subset of patients prone to experience clinically significant pain on injection with botulinum toxin type A to the face, such pain can be mitigated by selection of smaller­bore needles," the researchers concluded.

"To minimize avoidable expense, routine use of costly 32­gauge needles could be restricted to the subset of patients who have in earlier treatments encountered clinically significant pain with larger­bore needles," they said.

Dr. M. Laurin Council, from Washington University School of Medicine, St. Louis, Missouri, who wrote an editorial related to this report, told Reuters Health by email, "Small changes that we can make with respect to technique may make procedures more comfortable for patients. Patients appreciate when we do what we can to assure their comfort during medically necessary and cosmetic therapies."

"If a patient has a history of pain sensitivity during prior injection, one simple change that could result in less pain would be to switch to the 32­gauge needle," Dr. Council said.

She added, "Viscosity is an issue with smaller needles. Particularly with soft tissue augmentation, you must be able to physically inject the product through the needle. If the size of the gel particles is larger than the diameter of the needle, this simply will not work."

Dr. Billur Sezgin, reconstructive and anesthetic surgeon from Koc University School of Medicine, Erzurum, Turkey, told Reuters Health by email that these results "were quite similar to the results of a randomized clinical study that I had undertaken, which also demonstrated lower pain levels in facial injections with 33­gauge needles when compared to 30­gauge needles. I think that the results of both studies verify the importance of using thinner needles to promote a more comfortable experience during minimally invasive procedures." (http://bit.ly/1EZovF3)

"Although it is always a better choice to utilize the smallest needle possible when doing minimally invasive procedures, the depth of your injection can also be of importance when choosing the optimal needle as very fine needles tend to bend especially when they are being advanced into deeper tissues," Dr. Sezgin said, "So always go with the needle that you feel you gain the most control over while executing your work."

Dr. Alam did not respond to a request for comments.
The authors reported no external funding.
SOURCE: http://bit.ly/1LmEJFg and http://bit.ly/1ih9btH
JAMA Dermatol 2015.

Reuters Health Information © 2015

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