*Article*

#### **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**

**Takashi Hirai 1,\*, Toshitaka Yoshii 1, Kenichiro Sakai 2, Hiroyuki Inose 1, Masato Yuasa 1, Tsuyoshi Yamada 1, Yu Matsukura 1, Shuta Ushio 1, Shingo Morishita 1, Satoru Egawa 1, Hiroaki Onuma 1, Yutaka Kobayashi 1, Kurando Utagawa 1, Jun Hashimoto 1, Atsuyuki Kawabata 1, Tomoyuki Tanaka 1, Takayuki Motoyoshi 1, Takuya Takahashi 1, Motonori Hashimoto 1, Kentaro Sakaeda 1, Tsuyoshi Kato 1, Yoshiyasu Arai 2, Shigenori Kawabata 1 and Atsushi Okawa 1**

	- katoorth@gmail.com (T.K.); kawabata.orth@tmd.ac.jp (S.K.); okawa.orth@tmd.ac.jp (A.O.) 2Department of Orthopedic Surgery, Saitamaken-Saiseikai Kawaguchi General Hospital, 5-11-5 Nishikawaguchu, Kawaguchi City 332-8558, Japan; kenitiro1122@gmail.com (K.S.); arai.orth@gmail.com (Y.A.)

**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; hybrid fusion; ossification of the posterior longitudinal ligament; implant failure; graft subsidence; complications; perioperative outcomes; fusion rate; segmental paralysis; mechanical stability
