title: Pulsed Ho:YAG laser meniscectomy: effect of pulsewidth on tissue penetration rate and lateral thermal damage.
abstract: OBJECTIVE
  Studies need to define the optimal parameters under which the holmium laser should operate for arthroscopic meniscectomy. This study was designed to analyze the effect of various Holmium wavelength pulsewidths on human meniscal tissue penetration rates and lateral thermal injury.
  
  
  METHODS
  Using a pulsed Holmium: YAG laser at a wavelength of 2.1 microns, the effect of various pulse-widths on tissue penetration rates as well as the degree of accompanying thermal damage in human meniscal tissue was evaluated in a specially designed jig. Holding the energy constant at 500 mJ per pulse, the pulsewidth was varied between 100 and 600 microseconds.
  
  
  RESULTS
  Fiber penetration of meniscal tissue was found to be fastest at a pulsewidth of 250 microseconds. As the pulsewidth was increased or decreased around this number, the observed penetration time decreased, although no statistical difference was found. The size of the hole created was inversely related to the penetration time. Microscopic examination revealed zones of lateral thermal effect extending 800 microns from the ablation site.
  
  
  CONCLUSIONS
  No relationship between the pulsewidth and the lateral thermal effect could be found.
authors.affiliation: Department of Orthopaedics, University of Southern California School of Medicine, Los Angeles 90033-4608, USA.
authors.forename: C T
authors.initials: CT
authors.lastname: Vangsness
authors.forename: T
authors.initials: T
authors.lastname: Watson
authors.forename: V
authors.initials: V
authors.lastname: Saadatmanesh
authors.forename: K
authors.initials: K
authors.lastname: Moran
mesh_terms: D000328:Adult; D000368:Aged; D000535:Aluminum; D001182:Arthroscopy; D002056:Burns / Q000209:etiology* / Q000473:pathology; D006695:Holmium; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects* / Q000379:methods; D008592:Menisci, Tibial / Q000601:surgery*; D008875:Middle Aged; D000070600:Tibial Meniscus Injuries; D015019:Yttrium
chemical_list: D015019:Yttrium; D000535:Aluminum; D006695:Holmium