The anterior approach to ossification of the posterior longitudinal ligament of the cervical spine: The operative procedure

Abstract

Ossification of the posterior longitudinal ligament (OPLL) is a well-known cause of cervical radiculomyelopathy, and although an OPLL is commonly seen in Japanese with a cervical myelopathy, the incidence of an OPLL has been increasing among North Americans. The surgical treatment of a cervical OPLL is approached from a variety of anterior and posterior routes. However, the choice of surgical procedure used, which include a laminectomy, laminoplasty, or anterior decompression with fusion, still remains a topic of controversy. Between 1983 and 1993, the authors have performed an anterior decompression with interbody fusion for 51 patients with a cervical radiculomyelopathy due to an OPLL. To briefly describe this surgical method, after nasotracheal fiberoptic intubation, with the patient's head resting on a Mayfield padded horseshoe, a skin incision is made along the anteromedial border of the right sternocleidomastoid muscle. This approach thus allow sample exposure of the cervical spine from the C3 to T1 levels. Plain X-ray confirmation of the spinal level is then mandatory before vertebral dissection is initiated with an air drill. The multilevel vertebrectomy should be initiated under direct vision with a Midas Rex drill, so as to remove the majority of the bodies down to the posterior cortical margin. Once the posterior cortical margin is reached, all subsequent drilling should be conducted under operative microscopy using a diamond burr, since a diamond burr minimizes trauma to the dura and spinal cord and reduces bleeding. The egg-shell like, residual OPLL is then completed to remove with microkerrison punches and other microinstruments. After the complete decompression of the spinal cord, the dural theca almost always begins to protrude anteriorly with good pulsation. At this point a bone graft of an appropriate length from iliac crest is inserted in an inlay fashion. Postoperatively, in patients in whom more than 2 bodies are removed, a halo vest is applied for about 12 weeks. In conclusion, cervical cord compression caused by the lesions located principally in the anterior aspect of the spinal canal should be completely relieved by using an anterior approach.