For Botox injections, is there any benefit with using smaller needles?

The current standard seems to be 30-gauge needles for Botox, buta recent study shows that 33-gauge needles caused less pain.

(Investigations related to clinical needle derived pain also demonstrate that needle size is not the only factor affecting patient comfort level. In addition, the mechanics of needle insertion has been found to significantly affect pain. Both the force and the mechanical workload (i.e., area under the force-displacement curve) of hypodermic needle insertion have been found to positively correlate with the frequency of pain. Thus, needle tip sharpness and other factors, such as lubrication, which can reduce the force of insertion and mechanical workload, and pre-treatment with a topical anesthetic are important parameters that can be optimized to reduce pain from needle insertions.)

From the study:

The highest level of pain was in the malar region, and the lowest level was in the glabella. Although all pain scores were lower for the 33-G microneedle, the difference was significant only for the forehead. Because most minimally invasive procedures require multiple injections during the same sitting, the overall procedure was evaluated as well. Assessment of the multiple-injection process demonstrated a significant difference in pain level, favoring the 33-G needle. Although the difference in bruising was not statistically significant between the two needles, the degree of bruising was lower with the 33-G needle.

Conclusions: For procedures that involve multiple injections to the face (such as mesotherapy and injection of botulinum toxin A), thinner needles result in less pain, making the overall experience more comfortable for the patient and the physician.

There are a few other studies that show similar results and there are some contradictory findings from a study in 2010.

References:

1. The Effect of Microneedle Thickness on Pain During Minimally Invasive Facial Procedures: A Clinical Study. . Aesthetic Surgery Journal. 1 July 2014 Billur Sezgin MD, Bora Ozel MD, Hakan Bulam MD, Kirdar Guney MD, Serhan Tuncer MD, Seyhan Cenetoglu MD

2. Effect of Needle Size on Pain Perception in Patients Treated With Botulinum Toxin Type A Injections: A Randomized Clinical Trial. JAMA Dermatol. 2015 Nov;151(11):1194-9

3. Dermatol Surg. 2010;36(1):109-12. Needle preference in patients receiving cosmetic botulinum toxin type A. Price KM1, Williams ZY, Woodward JA.

4. Egekvist H, Bjerring P, Arendt-Nielsen L. Pain and mechanical injury of human skin following needle insertions. Eur J Pain. 1999 Mar;3(1):41-49.

5. Egekvist H, Bjerring P, Arendt-Nielsen L. Regional variations in pain to controlled mechanical skin traumas from automatic needle insertions and relations to ultrasonography. Skin Res Technol. 1999;247-54.

6. Schneider LW, Peck LS, Melvin JW. Penetration characteristics of hypodermic needles in skin and muscle tissue. Phase I (Appendices B-E). Final report. Highway Safety Research Institute, Ann Arbor, MI; 1978

7. Dermatol Surg. 2005 Dec;31(12):1655-9. Single-center, double-blind, randomized study to evaluate the efficacy of 4% lidocaine cream versus vehicle cream during botulinum toxin type A treatments. Carruthers A1, Carruthers J.

Originally published on LinkedIn by Michael Greenspan. Link