SPINA BIFIDA OCCULTA WITH ENGAGEMENT OF THE FIFTH LUMBAR SPINOUS PROCESS A Cause of Low Back Pain and Sciatica

Although spina bifida occulta has often been blamed in the past for backache and sciatica, I have believed neither that it was a common source of these troubles, nor that the fibrous band that closes the sacral breach is a cause of nerve root compression, as has been suggested by some authors. I have often explored a concomitant sacral defect while operating for a disc lesion, and have never found even the remotest possibility that this membrane could press on the contents of the spinal canal. Nevertheless spina bifida occulta may be associated with low back pain, because of the absence of the first sacral spinous process and the ligaments that normally run between it and the spinous process of the fifth lumbar vertebra. In the normal spine extension is often limited by the apposition of the fifth lumbar and first sacral spinous processes; because of the absence of the latter in spina bifida occulta there may be hypermobility in extension, and this may itself cause low back pain or sciatica.