Minimally Invasive Technologies for the Treatment of Hypertrophic Scars and Keloids: Intralesional Cryosurgery

AbstractA novel intralesional cryosurgical needle is inserted into the hypertrophic scars and keloid (HSK). It is connected to a canister of liquid nitrogen, which causes the cryoprobe to freeze, thereby freezing the HSK from inside out.Following the cryo-treatment, the histomorphometric analysis demonstrated rejuvenation of the treated scar. The frozen tissue was devoid of proliferating cells and of mast cells whereas the number of blood vessels remained unaltered.The surface thermal history showed slow cooling and thawing rates as well as less pronounced end temperature, which is “friendly” to the melanocytes, thus only minimal hypopigmentation was evident. A significant long hold time was documented. This allows time for solute effects, ice crystal formation, and recrystallization, which enhances and increases the rate of cell death. This long hold time is unique for the intralesional cryosurgery technology and might explain the superior clinical results.More than 50% of scar volume reduction was achieved following a single cryotherapy. For ear HSK, 70% of volume reduction was achieved, and for the upper back and shoulders 60%. Significant alleviation of objective and subjective clinical symptoms was documented. During the follow-up period there was no worsening or infection of the HSK and only minimal hypopigmentation.A pain control protocol was applied, which significantly reduced pain severity during and after the cryosurgery treatment to tolerable levels (VAS ≤ 3).The intralesional cryosurgery treatment is an evidence-based, effective, and safe technology, simple to operate, can be applied as an office procedure, is cost-effective, and takes a short learning curve. The technique achieves remarkable clinical results usually by a single treatment.