Ossification of the cervical posterior longitudinal ligament: a review.

Ossification of the cervical posterior longitudinal ligament (OPLL) represents a continuum beginning with hypertrophy of the posterior longitudinal ligament (PLL) followed by progressive coalescence of centers of chondrification and ossification. Early OPLL mimicking disc disease appears opposite multiple disc spaces associated with significant retrovertebral extension, helping to differentiate it from spondylosis. On computerized tomography examinations, the single- and double-layer signs indicate possible dural penetration with the increased potential for an intraoperative cerebrospinal fluid fistula during dissection. Direct ventral resection of OPLL in patients younger than 65 years of age is optimal and includes single- or multilevel anterior corpectomy with fusion, the latter accompanied by posterior fusion. For patients older than the age of 65 years, with a well-preserved cervical lordosis, laminectomy with or without fusion and/or laminoplasty may suffice in providing indirect dorsal decompression. Patients undergoing circumferential procedures with halo devices are managed with a specific anesthetic protocol, including awake intubation and positioning with intraoperative monitoring of somatosensory evoked potentials, electromyography, and the option of undergoing motor evoked potential monitoring. Intubation is maintained during the 1st postoperative night. When circumferential procedures are performed intubation is always maintained during the 1st postoperative night, and fiberoptic postoperative extubation is electively performed by specifically trained anesthesiologists when deemed appropriate. Patients exhibiting three or more major risk factors are considered candidates for delayed extubation and rarely, tracheostomy. Repeated anterior surgery, operations lasting more than 10 hours, involving four or more levels (including C-2), obesity, asthma, and blood transfusions of more than 4 U (1000-1200 ml) are all considered major risk factors.