Various studies have found a high incidence of early graft dislodgement after multilevel corpectomy. Although a hybrid fusion technique was developed to resolve implant failure, the hybrid and conventional techniques have not been clearly compared in terms of perioperative complications in patients with severe ossification of the posterior longitudinal ligament (OPLL) involving three or more levels. The purpose of this study was to compare clinical and radiologic outcomes between anterior cervical corpectomy with fusion (ACCF) and anterior hybrid fusion for the treatment of multilevel cervical OPLL. We therefore retrospectively reviewed the clinical and radiologic data of 53 consecutive patients who underwent anterior fusion to treat cervical OPLL: 30 underwent ACCF and 23 underwent anterior hybrid fusion. All patients completed 2 years of follow-ups. Implant migration was defined as subsidence > 3 mm. There were no significant differences in demographics or clinical characteristics between the ACCF and hybrid groups. Early implant failure occurred significantly more frequently in the ACCF group (5 cases, 16.7%) compared with the hybrid group (0 cases, 0%). The fusion rate was 80% in the ACCF group and 100% in the hybrid group. Although both procedures can achieve satisfactory neurologic outcomes for multilevel OPLL patients, hybrid fusion likely provides better biomechanical stability than the conventional ACCF technique.

In this paper, we present 2 cases of herniated nucleus pulposus (HNP) combined with the residual bony fragment of apophyseal ring fracture. HNP typically exists at the narrow lateral recess formed by the bony fragment, and so it has been reported that symptoms may persist. Case 1 was a 22-year-old man, a high-level javelin thrower and Paralympic athlete. He had a history of persistent pain for 4 years due to HNP, and so we performed surgical removal. Case 2 was a 23-year-old male professional baseball player. He was referred to us only 17 days after the onset of pain and presented with muscle weakness, a feature which may prolong the clinical course in addition other features such as pain. Thus, we performed a comparatively quick intervention of surgical removal. In both cases, we had excellent clinical outcomes and better function and performance. In conclusion, in cases with HNP and apophyseal ring separation, surgical intervention in the comparatively early phase can be recommended, particularly if the patients desire quick return to their original level of activity. J.