Is the zero-profile anchored cage sufficient and safe for Microscope-assisted anterior cervical discectomy and fusion with oblique resection of posterior endplate in the treatment of degenerative cervical disease? A preliminary study.

PURPOSE: The study aims to evaluate the efficacy and safety of a modified microscope-assisted anterior cervical discectomy and fusion (ACDF) technique incorporating oblique resection of the posterior endplate (ORPE) in the treatment of degenerative cervical disease due to osteophyte osteophytes or ossification of the posterior longitudinal ligament (OPLL). Furthermore, we compare clinical and radiological outcomes between plate-cage constructs (PCC) and Zero-P integrated cages, and investigate the factors influencing the extent and angle of endplate resection.

METHODS

A total of 62 patients who underwent ACDF with ORPE were included (PCC group: 30 patients; Zero-P group: 32 patients). Clinical outcomes, radiological parameters, oblique resection metrics, and complications were systematically evaluated. Factors influencing the oblique resection geometry were further analyzed.

RESULTS

There were no significant differences in baseline demographic and clinical characteristics between the two groups (P > 0.05). Postoperative follow-up revealed significant improvements in VAS, JOA, and NDI scores in both groups (all P < 0.05). Each group experienced one case of cerebrospinal fluid leakage, which was managed conservatively without sequelae. Radiologically, both groups demonstrated postoperative improvement in cervical lordosis and occupation ratio. However, no significant intergroup differences were observed in fusion rates, cage subsidence, or screw loosening (all P > 0.05). Further analysis revealed that the resection ratio and angle increased progressively from C3/4 to C6/7 level. A significant linear correlation was observed between these resection parameters and the superior endplate slope of the caudal vertebral body (P < 0.05).

CONCLUSION

ACDF with ORPE under microscope using either a PCC or a Zero-P cage, has demonstrated satisfactory clinical outcomes and radiological results. Bilateral oblique resection facilitates extensive anterior decompression while preserving approximately 46% of the posterior vertebral wall per segment. Additionally, the resection ratio and angle are correlated with the superior endplate slope of the caudal vertebra in the discectomy.