title: Principles and applications of laser lithotripsy: experience with the holmium laser lithotrite.
abstract: OBJECTIVE
  The initial clinical experience with holmium laser energy applied for endoscopic lithotripsy was positive. The current study is presented as a contrast to the preliminary findings and as a means of defining the clinical usefulness of this specific laser lithotrite.
  
  
  METHODS
  Calculi were treated endoscopically with the holmium laser lithotriptor and data was gathered prospectively. The youngest patient in the series was a thirteen-month--old who underwent percutaneous therapy, while the youngest patient on whom a retrograde endoscopic procedure was performed was a six-year old male patient with a proximal ureteral calculus. Lower water density, quartz fibers delivery systems were developed and employed. Fiber diameters ranged from 200-1000 micrograms. The smaller fibers were employed most commonly through the actively deflectable, flexible endoscope to facilitate treatment with maximum deflection. Larger fibers, with their much larger vaporization bubbles, were used through rigid endoscopes to debulk large stone burdens.
  
  
  RESULTS
  A total of 210 patients with 249 calculi were treated. All major stone compositions were treated with minimal variation in laser efficiency. All but three of 109 ureteral calculi were treated in a retrograde fashion to completion (i.e., "stone free") in one sitting (97%). One-hundred thirteen renal stone burdens were treated with the holmium laser; 99 of these were treated solely in a retrograde fashion. Of the latter, 79 (80%) required only a single session. The combination of the actively deflectable, flexible ureteroscope and the 200-micrograms fiber facilitated treatment to completion of 38 to 45 lower-pole caliceal calculi (85%). The success of ureteropyeloscopic lithotripsy with the holmium laser for all intrarenal calculi, including staged or second sitting for large complex stone burdens, was 90%. Sixteen percutaneous procedures (13 renal and 3 ureteral calculi) employed the holmium laser as an endoscopic lithotrite. All 28 patients with large bladder calculi with a mean diameter of 41.8 mm were treated to completion in one sitting. Complications from holmium laser energy, including postoperative ureteral stricture disease, were not encountered in this series.
  
  
  CONCLUSIONS
  Holmium laser energy is uniquely suited to treat urinary calculi safely regardless of stone size, location, or metabolic composition, and has particular efficacy in complex clinical presentations.
authors.affiliation: Department of Urology, New York University Medical Center, New York, NY 10016, USA.
authors.forename: M
authors.initials: M
authors.lastname: Grasso
authors.forename: Y
authors.initials: Y
authors.lastname: Chalik
mesh_terms: D002648:Child; D019723:Endoscopes; D006695:Holmium; D006801:Humans; D007223:Infant; D017602:Lithotripsy, Laser / Q000295:instrumentation / Q000379:methods; D008297:Male; D010043:Outcome and Process Assessment, Health Care; D014545:Urinary Calculi / Q000601:surgery*
chemical_list: D006695:Holmium