title: Acne treatment with a 1,450 nm wavelength laser and cryogen spray cooling.
abstract: OBJECTIVE
  A laser with a wavelength in the mid-IR range targeting the depth in skin where sebaceous glands are located in combination with cryogen spray cooling was evaluated for treatment of acne. In this non-ablative treatment, the laser energy heats the dermal volume encompassing sebaceous glands whereas the cold cryogen spray preserves the epidermis from thermal damage.
  
  
  METHODS
  Monte Carlo simulations and heat transfer calculations were performed to optimize the heating and cooling parameters. A variety of heating and cooling parameters were tested in an in vivo rabbit ear study to evaluate the histological effect of the device on sebaceous glands and skin. Similar experiments were performed on ex vivo human skin. A clinical study for the treatment of acne on backs of human males was also conducted.
  
  
  RESULTS
  Monte Carlo simulations and heat transfer calculations resulted in a thermal damage profile that showed epidermal preservation and peak damage in the upper dermis where sebaceous glands are located. Ex vivo human skin histology confirmed the damage profile qualitatively. In vivo rabbit ear histology studies indicated short-term thermal alteration of sebaceous glands with epidermal preservation. In the human clinical study on the back, a statistically significant reduction in lesion count on the treated side compared to the control side was seen (p < 0.001). Side effects were transient and few.
  
  
  CONCLUSIONS
  The studies reported here demonstrate the feasibility of treating acne using a photothermal approach with a mid-IR laser and cryogen cooling.
authors.affiliation: Candela Corporation, 530 Boston Post Road, Wayland, Massachusetts 01778, USA. dilip.paithankar@c1zr1.com
authors.forename: Dilip Y
authors.initials: DY
authors.lastname: Paithankar
authors.forename: E Victor
authors.initials: EV
authors.lastname: Ross
authors.forename: Bilal A
authors.initials: BA
authors.lastname: Saleh
authors.forename: Mark A
authors.initials: MA
authors.lastname: Blair
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Graham
mesh_terms: D000152:Acne Vulgaris / Q000473:pathology / Q000628:therapy*; D000818:Animals; D003131:Combined Modality Therapy; D017679:Cryotherapy; D004195:Disease Models, Animal; D004817:Epidermis / Q000473:pathology / Q000528:radiation effects; D005500:Follow-Up Studies; D006801:Humans; D066298:In Vitro Techniques; D053685:Laser Therapy; D008297:Male; D011817:Rabbits; D012627:Sebaceous Glands / Q000473:pathology / Q000528:radiation effects; D013997:Time Factors; D016896:Treatment Outcome