Of twenty-two patients who had had anterior decompression of the spinal
canal for ossification of the posterior longitudinal ligament and cervical
myelopathy, seven had absence of the dura adjacent to the ossified part of
the ligament. The spinal cord and nerve-roots were visible through this
defect. Although the arachnoid membrane appeared to be intact and
watertight in most patients, a cerebrospinal-fluid fistula developed
postoperatively in five, and three had a second operation to repair the
defect in the dura. On the basis of this experience, we recommend use of
autogenous muscle or fascial dural patches, immediate lumbar subarachnoid
shunting, and modification of the usual postoperative regimen, such as
limitation of mechanical pulmonary ventilation to the shortest time that is
safely possible and use of anti-emetic and antitussive medications to
protect the remaining coverings of the spinal cord when the dura is found
to be absent adjacent to an ossified portion of the posterior longitudinal
ligament in the cervical spine.