| Objective:.To compare the short-term surgical outcomes of anterior cervical decompression and fusion (ACDF) with that of laminoplasty with/without instrumented fusion for patients with cervical ossification of the posterior longitudinal ligament and to analyse the predictors of the surgical outcomes for all cases.Data and method:.Fourteen patients of cervical ossification of the posterior longitudinal ligament were treated with ACDF from August 2006 to August 2008 and 11 of them were followed up more than 12 months (A-group). The author retrieved his hospital's medical records library for the cases of cervical ossification of the posterior longitudinal ligament who underwent laminoplasty with/without instrumented fusion from January 2003 to July 2006 and 14 cases were found meeting the criteria of inclusion and exclusion. The Japanese Orthopedic Association scoring system(JOA) was used to evaluate cervical neurological functions and the recovery rates were calculated and compared between the two groups at 12-month follow-up. In order to identify the predictors of the surgical outcomes, all the patients of the two groups were combined and then divides into two groups according the recovery of neurologic function: a good outcome group comprising patients whose recovery rate was 50% or higher and a poor outcome group comprising patients whose recovery rate was less than 50%. The facors possibly affecting surgical outcomes proposed by previous authors were compared between the"good outcome"and"bad outcome"group and if there is statistical difference, the fator will be considerd as affecting the surgical outcomes. Result: The two groups showed no statistical difference in preoperative data including sex, age, duration of symptoms, coexisting of diabetes mellitus, traumatic history, JOA score, Nurick grade, cervical spine curverture, segmental instability, occupancy ratio of OPLL to the canal, the longitudinal extent of OPLL and magnetic resonance findings such as the degrees of spinal cord ?attening and intra-medullar high signal intensity(IMHSI). In A-group, nine patients were treated with anterior corpectomy and direct resection of OPLL and 2 were treated with anterior floating method. In P-group, ten cases underwent laminoplasy only and another 4 cases underwent laminoplasty and instrumented fusion. The mean surgical time was 138.6±47.3mins(100～270mins) in the A-group and 108.6±28.2mins(70～160mins) in P-group, a di?erence that was not significant (P=0.06). The mean blood loss volume was 518.2±426.8ml(250ml～1750ml) in A-group and 332.1±140.9ml(200ml～750ml) in P-group, again a di?erence that was not significant (P=0.14). Despite comparable preoperative data, the anterior surgery, although technically more demanding, showed a significantly better cervical spinal functional recovery and better cervical spine curverture (P<0.05) with no neurologic or graft-related complications at 12-month follow-up,although there was no significant difference in term of the mean JOA score(14.6±1.9vs12.6±3.0). In comparison, laminoplasty, in spite of instrumented fusion in 4 of the 14 cases, was associated with cervical kyphosis in 2 patients and segmental instability in 2 case(one coexsiting of kyphosis). Seven patients, one in A-group and 6 in P-group, had a recovery rate less than 50%. The analysis of surgical prognostic factors showed that the poor surgical outcomes could be attributed to coexisting of DM, cervical traumatic history, the high grade of Nurick scale (P<0.05).Conclusion: The results demonstrated that for those cervical OPLL cases whose surgical indications were strictly defined, the surgical outcome of ACDF was superior to that of laminoplasty with/without instrumented fusion at short-term follow-up, what is more, it seems counterintuitively safer than laminoplasy. The results of analysis of predictors of surgical outcomes showed that the factors causing poor surgical outcomes included coexisting of DM, traumatic history and the high grade of Nurick scale.
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