CHARACTERIZATION OF LUMBAR SPINE ANNULAR DISRUPTION IN PMHS USING MRI, CRYOMICROTOMY AND HISTOLOGY TECHNIQUES

摘要

Internal intervertebral disc disruption is involved in the onset of a wide range of spinal dysfunction, ultimately affecting notonly the disc itself but the surrounding osseous and neural structures as well. The ability of disc to withstand and effectivelydistribute axial load is dependent upon whether peripherally located annular fibers provide the support necessary to containand corral the pressure sensitive nucleus. Any alteration in the structures immediate to the nucleus jeopardize this ability.While annular tears and fissures have been thoroughly investigated, one form of internal disc disruption is less wellunderstood.A network of elastin cross-bridges provides resistance to delamination of the collagenous sheets that comprisethe annulus. The current investigation utilized a Nitrogen gas-induced pressure mechanism to disrupt elastin cross links thatexist between annular lamellae. Twenty five cadaveric lumbar spine motion segments (mean age: 52±12 yr.) were subjectedto the annular disruption protocol. Damage to the annulus was assessed using MRI, cryomicrotome and histological stainingprocedures. MRI images were compared to cryomicrotome images to determine the ability of standard clinical MRI scans todetermine annular damage. In many cases MRI was moderately revealing in terms of damage. Future studies will quantifybiomechanical consequences of these low level annular disruptions relative to segmental stability.