Biomechanical evaluation of destabilization following minimally invasive decompression for lumbar spinal canal stenosis

Object This study aimed to clarify changes in segmental instability following a unilateral approach for microendoscopic posterior decompression and muscle-preserving interlaminar decompression compared with traditional procedures and destabilized models. Methods An ex vivo experiment was performed using 30 fresh frozen porcine functional spinal units (FSUs). Each intact specimen was initially tested for flexion-extension, lateral bending, and torsion up to 1.5° using a material testing system at an angular velocity of 0.1°/second under a preload of 70 N. Microendoscopic posterior decompression, muscle-preserving interlaminar decompression, bilateral medial facetectomy, left unilateral total facetectomy, and bilateral total facetectomy were then performed, followed by mechanical testing with the same loading conditions, in 6 randomized FSUs from each group. Stiffness and neutral zone were standardized by dividing the experimental values by the baseline values and were then compared among groups. Results Me...