Use of a vibration tool to reduce pain from growth factors injection in the treatment of androgenetic alopecia: a randomized controlled trial

Objective: local anesthetics (cream or tape) are often used to reduce pain associated with injection procedures, but might not be sufficiently effective or applicable when treating the scalp for androgenetic alopecia with growth factors injection. The aim of this randomized controlled trial was to determine whether the application of microvibratory stimulation during scalp injection would decrease pain reported by patients. Methods: fifty consenting patients scheduled to undergo growth factors injections for the treatment of androgenetic alopecia were recruited. The study period was 12 months, with a single surgeon performing all procedures. The treatment area was divided in two equal halves and subjects were randomized to receive injections with vibration given by a mini massager in the first zone, and then no vibration in the second zone, or viceversa. At the end of the session, all patients were asked to express the level of discomfort of each procedure, using the Numeric Rating Scale. Results: out of the 50 patients, 39 reported that vibration relieved the pain, 10 stated that it had no effect, and 1 complained that it made the pain worse. Vibration did not affect the safety of the injections. The average Numeric Rating Scale scores for the no-vibration and vibration injections were 5.34 and 4.16 respectively (p≤ 0.05). Conclusions: vibration reduces pain associated with needling/injection of the scalp. The Gate Control Theory of Pain explains this effect.