Anterior Controllable Antedisplacement Fusion (ACAF) for Severe Cervical Ossification of the Posterior Longitudinal Ligament: Comparison with Anterior Cervical Corpectomy with Fusion (ACCF)

OBJECTIVE: Anterior cervical corpectomy and fusion (ACCF), in which a ventral constriction is resected, can decompress myelopathy and is considered the optimal treatment for ossification of the posterior longitudinal ligament (OPLL) up to now. However, its disadvantages are incomplete decompression, high surgery- and implant-related complication rates, and extremely surgical technique demanding. Our object was to introduce anterior controllable antedisplacement fusion (ACAF), a new surgical technique to treat OPLL, and compare it with ACCF. METHODS: ACAF was performed on 34 patients with spinal stenosis with myelopathy due to severe (occupying rate >= 50%) OPLL. Pre- and postoperatively, we measured decompression width and spinal canal area on cross-sectional computed tomography and morphology and anteroposterior diameter of the spinal cord at the most severely affected segment on cross-sectional magnetic resonance imaging and cross-sectional computed tomography. Japanese Orthopedic Association scoring was used to evaluate neurologic status. The ACAF group and a control group of 36 patients with ACCF were compared. RESULTS: Postoperatively, decompression width (17.9 +/- 1.0 vs. 15.1 +/- 0.8 mm; P < 0.01), spinal canal area (150.4 +/- 31.6 vs. 127.0 +/- 27.0 mm(2); P < 0.01), and anteroposterior spinal cord diameter (5.4 +/- 0.6 vs. 5.0 +/- 1.1 mm; P < 0.05) were significantly greater in the ACAF group. At 6 months, mean Japanese Orthopedic Association score was significantly better in the ACAF group (15.4 +/- 0.9 vs. 14.5 +/- 2.5 points; P = 0.04). CONCLUSIONS: ACAF, providing adequate decompression of the spinal cord and good outcomes, is a well choice in the treatment of spinal stenosis due to severe OPLL.