Stability of the lumbar spine after intradiscal electrothermal therapy

Objective: To assess the stability of the human lumbar cadaveric spinal motion segment before and after treatment with intradiscal electrothermal therapy (IDET). Design: An in vitro biomechanic analysis of 5 human cadaveric spinal motion segments by using nondestructive biomechanic testing in flexion/extension, lateral bending, and axial rotation with loads of ON, 600N, and 1200N. Setting: University-based hospital research center. Cadavers: Spinal unit specimens (upper and middle lumbar) from 5 human cadavers (age range, 39-79yr). Interventions: A spinal catheter consisting of a thermal-resistive heating coil was placed circumferentially into the outer annulus by using the standard extrapedicular discographic technique through a 17-gauge introducer needle. The disc was then heated in a saline bath (37°C) from 65°C up to 90°C for a total of 17 minutes. Main Outcome Measure: The stability of the spinal segments was measured before and shortly after IDET. Stability of the spine was measured as the compliance of the spine (the angular deformation afforded by the spine under applied bending moments). Results: With increasing preloads, there is a decrease in motion of the spinal segment in all planes of testing. However, there was no significant difference (p > .05) in the stability of the lumbar spine before and after treatment with IDET. Conclusions: IDET does not destabilize the spinal motion segment in vitro.