Patterns of Short-Term and Long-Term Surgical Outcomes and Prognostic Factors for Cervical Ossification of the Posterior Longitudinal Ligament Between Anterior Cervical Corpectomy and Fusion and Posterior Laminoplasty

Abstract

To compare short-term and long-term surgical outcome patterns between anterior cervical corpectomy and fusion (ACCF) and laminoplasty (LP) in patients diagnosed with cervical ossification of the posterior longitudinal ligament (OPLL) and identify factors affecting surgical outcomes based on follow-up duration. During short-term follow-up period, surgical outcomes between ACCF and LP were similar. However, there were several reports that long-term surgical outcomes were superior in the ACCF compared with LP. Surgical outcomes between ACCF and LP according to follow-up period changed. This study enrolled 70 patients who underwent ACCF and 63 patients who underwent LP between 2005 and 2012. Patterns of surgical outcomes were analyzed in accordance with surgical procedures. Furthermore, these patients were divided into two subgroups in respect of follow-up duration: the short-term group (less than 48 months) and the long-term group (more than 48 months) group. Occupying ratio, type of OPLL, shape of ossified lesion, cervical sagittal alignment, grade of signal intensity on MRI, and Japanese Orthopedic Association (JOA) score were examined. Surgical outcomes of ACCF went into reverse at 48-month follow-up period. In the short-term group, JOA recovery rate had no difference between ACCF and LP. In the long-term group, the ACCF recovery rate (78.5 ± 31.0) was significantly higher than the LP recovery rate (48.4 ± 54.9) (P = 0.008). In the short-term group, old age (p = 0.011), hill shape (p = 0.013), and high grade of MRI signal intensity (p = 0.040) had negative effects on recovery rate. On the other hand, in the long-term group, LP (p = 0.021) and a high grade of MR signal intensity (p = 0.017) independently and negatively affected recovery rate. Long-term surgical outcomes of ACCF became better than those of LP at more than 48-month follow-up period. High-grade MRI signal changes and the LP surgical procedure were independent negative factors for long-term surgical outcomes in patients with OPLL. Direct decompression of the spinal cord with ACCF provides better long-term stable neurologic outcomes than LP.