Anterior Cervical Corpectomy with Fusion versus Anterior Hybrid Fusion Surgery for Patients with Severe Ossification of the Posterior Longitudinal Ligament Involving Three or More Levels: A Retrospective Comparative Study

Abstract

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.

Keywords: anterior cervical corpectomy and fusion; complications; fusion rate; graft subsidence; hybrid fusion; implant failure; mechanical stability; ossification of the posterior longitudinal ligament; perioperative outcomes; segmental paralysis.

Figure 1

Long semi-constrained plate fixation with artificial bone graft. (a) Preoperative radiograph showing the C2–7 lordotic angle, C-SVA, and T1 slope. Postoperative radiographs (b) after dual-level corpectomy (C4–5) and ossification floating decompression and (c) with dual artificial bone graft after discectomy (C3/4) and single corpectomy (C5). (d) Postoperative radiograph showing fused segment angle and fused segment height in the ACCF group. (e) Postoperative radiograph showing fused segment angle and fused segment height in the hybrid group.

Figure 2

Radiographic measurement of (a) C2–7 angle; (b) C2–7 SVA; (c) T1 slope; (d) FSA; and (e) FSH in the ACCF and hybrid groups.

Figure 3

(a) Plot showing changes in FSA and FSH (ΔFSA and ΔFSH) and the incidence of graft subsidence; (b) Plot showing associations between absolute values of ΔFSA and ΔFSH and graft migration. A large |ΔFSH| is more closely linked with graft migration than |ΔFSA|.