The Effect of an Interspinous Process Implant on Facet Loading During Extension

Study Design. Facet loading parameters of lumbar ca-daver spines were measured during extension before and after placement of an interspinous process implant. Objective. The study was undertaken to quantify the influence of an interspinous implant on facet loading at the implanted and adjacent levels during extension. Summary of Background Data. Facet loading is in-creased during extension and decreased during flexion. Previous studies have demonstrated that interspinous process decompression relieves disc pressure at the im-planted level and does not alter disc pressure at the ad-jacent levels. Facet joints are believed to play a key role in back pain, especially in patients with collapsed discs and increased motion segment mobility resulting in increased facet loading