Experimental determination of the effect of progressive sharp-angle spinal deformity on the spinal cord.

Neurological deficit is a serious though not well-known complication associated with spinal deformity. Sharp-angle kyphosis may be congenital, traumatic, degenerative, infectious, or iatrogenic in origin. Many kyphotic deformities are underestimated, thus leading to severe neurological deficit. In order to determine exactly what procedures of angulation the patients should undergo to stabilize the spine, which are major operations, the authors analyzed in an experimental model the effects of progressive sharp angulation on the anatomy of spinal canal and cord. We found that sharp anterior angulation of 50 degrees causes anterior-posterior stenosis and the dura will touch the spinal cord. At 90 degrees of angulation, the spinal cord will be squeezed and the pressure in the canal will be double what it was initially, probably leading to ischemia. The experimental confirmation (determination) of these angulations allows the physician in charge to define early in the treatment program when a surgical stabilization procedure should be included, before the angulation causes any neurological damage.