ASSESSMENT OF NEUROFORAMINAL DECOMPRESSION IN DEGENERATIVE SPINAL STENOSIS

Surgical decompression of spinal stenosis is a balance between adequat e removal of bone and soft tissue for an effective decompression of ne ural structures and a sufficient retention of bone to maintain mechani cal stability of the spine, To develop an objective, reproducible tech nique for the assessment of neuroforaminal decompression in the adult lumbar spine, facet sparing laminectomies mere performed from L1-S1 on the lumbar spines of 59 human cadavers, A series of semirigid probes in 0.5-mm increments were passed into each successive intervertebral f oramen bilaterally, beginning at L2-L3, The minimum space available fo r the nerve root within the foramen of the lumbar spine is 3.5 mm at L 2-L3, 3.9 mm at L3-L4, 4.3 mm at L4-L5 and 5.1 mm at L5-S1, as determi ned by three independent observers, There were no significant differen ces in interobserver or intraobserver measurements, There mere no comp lications related to passage of the probes, This study pro,ides a meth od for the intraoperative determination of the adequacy of neuroforami nal decompression.