title: The evolution of percutaneous spinal endoscopy and discectomy: state of the art.
abstract: OBJECTIVE
  The author relates his 7 years' experience with endoscopic spine surgery for lumbar disc herniations and conditions previously treated only with more invasive methods.
  
  
  METHODS
  Five hundred (500) patients were treated with the Yeung endoscopic spine system, which features an endoscope with a 2.8 mm operating channel. The protocol included preoperative or intraoperative discography in all cases. Adjuvant therapies were employed in various clinical conditions when dictated by the visualized spinal pathology--KTP laser (Laserscope, San Jose, CA) in 100 patients, radiofrequency by electrothermal probe in 400 patients, chymopapain in 50 cases, and intraoperative steroids in 100 cases. A newer slotted tube system allowed for foraminoplasty and removal of osteophytes or extruded fragments.
  
  
  RESULTS
  Good-to-excellent results were recorded in 432 of the 500 patients (86.4%). Separate analysis was made of the first 100 cases when the KTP laser was in use.
  
  
  CONCLUSIONS
  The 2.8 mm operating channel scope produced clear visualization of annular tears, disc fragments, foraminal osteophytes, and the epidural space. Monitoring of the microinstruments in the disc space and spinal canal was readily accomplished. The quality of the imaging provided by discography improved the definition of the disc pathology. Adjuvant use of lasers, radiofrequency, chymopapain, and intradiscal steroids and the newer slotted tube system, have contributed to the advances in minimally invasive technique for endoscopic discectomy.
authors.affiliation: Squaw Peak Surgical Facility, Phoenix, AZ, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Yeung
mesh_terms: D000328:Adult; D000368:Aged; D017587:Diskectomy, Percutaneous / Q000295:instrumentation*; D004724:Endoscopy; D004867:Equipment Design; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D053685:Laser Therapy / Q000379:methods; D008159:Lumbar Vertebrae; D008875:Middle Aged; D012189:Retrospective Studies