Topical cryoanesthesia for the relief of pain caused by steroid injections used to treat hypertrophic scars and keloids

Abstract

Intralesional steroid injections are the standard treatment for hypertrophic scars and keloids. The procedure is, however, quite painful and is unpopular with patients because of this. Topical application of anesthetic creams, such as Ametop gel (tetracaine) and EMLA cream (lidocaine and prilocaine), has limited efficacy because of poor drug penetration. The onset of the analgesic effect is also slow, which means that the use of topical anesthetics is time-consuming in clinical practice.We hypothesized that a commercially available cryotip could be used to provide fast-acting topical cryoanesthesia that would reduce the pain associated with steroid injections.Thirty patients with hypertrophic scars or keloids were enrolled in the study. Scars were injected with the steroid, triamcinolone acetonide, with or without prior application of the cryotip (-10 °C) for 15 seconds. The degree of pain was evaluated in each case using the visual analogue scale (VAS) and the verbal descriptor scale (VDS), together with any side-effects caused by application of the cryotip.The VAS pain scores showed a statistically significant (P < .01) difference between the pretreated and the control scars (pain scores 7.87 ± 1.31 and 2.7 ± 1.37, respectively). The VDS pain scores also showed a statistically significant (P < .01) difference between the pretreated and the control scars. And its average scores were 7.89 ± 0.32 and 2.68 ± 0.25, respectively.Application of the cryotip before injection could provide a rapid and effective means of reducing the pain associated with steroid injections. Painless would result in better therapeutic effect.

Figure 1

Cryotip device.

Figure 2

Injection sites used in 1st (A–C) and 2nd (D–E) protocols. In the 1st protocol, 2 adjacent scars were randomly designated as control or experimental. The control scar was injected without cryoanethesia (A). The cryotip was placed on the experimental scar for 15 seconds (B) before injection (C). In the 2nd protocol, the scar to be treated was divided into 2 parts down a center line. The control side was injected without cryoanethesia (D). The cryotip was then placed on the experimental side for 15 seconds (E) before injection (F).

Figure 3

(A) Visual analogue scale and (B) verbal descriptor scale.

Figure 4

Pain intensity scores determined using visual analogue scale (VAS). There is a significant difference between the control group and the group that received cryoanesthesia (P < .01).

Figure 5

Pain intensity scores determined using verbal descriptor scale (VDS). There is a significant difference between the control group and the group that received cryoanesthesia (P < .01).