A biophysical explanation for Nd : YAG percutaneous laser disc decompression success

Objective: To use pre- and postoperative CT density measurements to demonst rate changes achieved by Nd:YAG laser (1,064 nm) in protruded or extruded d iscs. Background Data: Nonendoscopic percutaneous laser disc decompression and nucleotomy (PLDN) with the Nd:YAG laser is an established minimal invas ive treatment of discogenic pain syndromes in patients with bulging, protru ded, or extruded intravertebral discs. Extremely high success rates involvi ng improvement in the flow of cerebrospinal fluid in the dural sac and enha nced venous flow by MRI myelography are 80% lumbar, 86.5% cervical, and 98% thoracic spine. However, verification of reduced intradisc and intraspinal pressure by imaging procedures is difficult. Methods: Twenty-one patients, four women and 17 men, with an average age of 43.67 (range, 24-59) were se lected. The patients showed lumbar radicular pain syndromes with monosegmen tal disc protrusion or extrusion, and monoradicular clinical symptoms. Meas urements were performed preoperatively and on postoperative day 1. Results: The preoperative density measurements averaged 83.43, in agreement with th e Houndsfield units (HU) described in the literature. Postoperatively, the reduction down to 66.33 HU had a statistical significance of p = 0.001 veri fied in the t test. Standardizing the measurements prior to laser irradiati on to 100% produced an average 20% postoperative density reduction. Conclus ion: PLDN with the Nd:YAG laser (1,064 nm) markedly reduces the postoperati ve density in protrusion and extrusion of intravertebral discs. The excelle nt therapeutic results achieved with this method in discogenic pain syndrom es can be verified by imaging procedures.