LASER DISKECTOMY - COMPARISON OF SYSTEMS

Percutaneous methods of lumbar disc removal have gained wide popularit y since the introduction of the automated suction device. Newer method s to enter this field include the Nd:YAG and Ho:YAG lasers. To date, n o experimental model exists to compare the efficacy of disc removal of these devices. An in vitro disc elastance (pressure/volume) model was designed that accurately reflects the mass of dry disc removed after any type of discectomy procedure. The experimental design consists of an infusion pump compressing a static column of air in line with the d isc through a 12-gauge needle. Both mechanical and laser devices exhib ited a reproducible treatment plateau, beyond which no disc removal wa s effected. Total energy, as opposed to power, was found to be the mai n determinant of the extent of disc removal during laser discectomy. F inally, in the experimental model of juvenile swine the automated suct ion device exhibited superior disc removal compared to the two lasers, but the clinical applicability of this is debatable. Disc space elast ance offers a rapid and reproducible method to quantitate the extent o f disc removal after intradiscal treatment methods and if employed in human cadaver spines may minimize the need for clinical trials to comp are different devices and techniques.