title: Differences between C3-4 and other subaxial levels of cervical disc arthroplasty: more heterotopic ossification at the 5-year follow-up.
abstract: OBJECTIVE Several large-scale clinical trials demonstrate the efficacy of 1- and 2-level cervical disc arthroplasty (CDA) for degenerative disc disease (DDD) in the subaxial cervical spine, while other studies reveal that during physiological neck flexion, the C4-5 and C5-6 discs account for more motion than the C3-4 level, causing more DDD. This study aimed to compare the results of CDA at different levels. METHODS After a review of the medical records, 94 consecutive patients who underwent single-level CDA were divided into the C3-4 and non-C3-4 CDA groups (i.e., those including C4-5, C5-6, and C6-7). Clinical outcomes were measured using the visual analog scale for neck and arm pain and by the Japanese Orthopaedic Association scores. Postoperative range of motion (ROM) and heterotopic ossification (HO) were determined by radiography and CT, respectively. RESULTS Eighty-eight patients (93.6%; mean age 45.62 ± 10.91 years), including 41 (46.6%) female patients, underwent a mean follow-up of 4.90 ± 1.13 years. There were 11 patients in the C3-4 CDA group and 77 in the non-C3-4 CDA group. Both groups had significantly improved clinical outcomes at each time point after the surgery. The mean preoperative (7.75° vs 7.03°; p = 0.58) and postoperative (8.18° vs 8.45°; p = 0.59) ROMs were similar in both groups. The C3-4 CDA group had significantly greater prevalence (90.9% vs 58.44%; p = 0.02) and higher severity grades (2.27 ± 0.3 vs 0.97 ± 0.99; p = 0.0001) of HO. CONCLUSIONS Although CDA at C3-4 was infrequent, the improved clinical outcomes of CDA were similar at C3-4 to that in the other subaxial levels of the cervical spine at the approximately 5-year follow-ups. In this Asian population, who had a propensity to have ossification of the posterior longitudinal ligament, there was more HO formation in patients who received CDA at the C3-4 level than in other subaxial levels of the cervical spine. While the type of artificial discs could have confounded the issue, future studies with more patients are required to corroborate the phenomenon.
authors.affiliation: Departments of 1 Neurosurgery, Neurological Institute and.|School of Medicine, National Yang-Ming University;
authors.forename: Peng-Yuan
authors.initials: PY
authors.lastname: Chang
authors.affiliation: Departments of 1 Neurosurgery, Neurological Institute and.|School of Medicine, National Yang-Ming University;
authors.forename: Hsuan-Kan
authors.initials: HK
authors.lastname: Chang
authors.affiliation: Departments of 1 Neurosurgery, Neurological Institute and.|School of Medicine, National Yang-Ming University;
authors.forename: Jau-Ching
authors.initials: JC
authors.lastname: Wu
authors.affiliation: Departments of 1 Neurosurgery, Neurological Institute and.|School of Medicine, National Yang-Ming University;
authors.forename: Wen-Cheng
authors.initials: WC
authors.lastname: Huang
authors.affiliation: Departments of 1 Neurosurgery, Neurological Institute and.|School of Medicine, National Yang-Ming University;|Institute of Pharmacology, National Yang-Ming University; and.
authors.forename: Li-Yu
authors.initials: LY
authors.lastname: Fay
authors.affiliation: Departments of 1 Neurosurgery, Neurological Institute and.|School of Medicine, National Yang-Ming University;|Molecular Medicine Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan.
authors.forename: Tsung-Hsi
authors.initials: TH
authors.lastname: Tu
authors.affiliation: Radiology, Taipei Veterans General Hospital;|School of Medicine, National Yang-Ming University;
authors.forename: Ching-Lan
authors.initials: CL
authors.lastname: Wu
authors.affiliation: Departments of 1 Neurosurgery, Neurological Institute and.|Radiology, Taipei Veterans General Hospital;|School of Medicine, National Yang-Ming University;
authors.forename: Henrich
authors.initials: H
authors.lastname: Cheng
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000209:etiology / Q000473:pathology*; D016059:Range of Motion, Articular; D059145:Total Disc Replacement / Q000009:adverse effects*; D016896:Treatment Outcome
keywords: ACDF = anterior cervical discectomy and fusion; C3–4; CDA = cervical disc arthroplasty; DDD = degenerative disc disease; HO = heterotopic ossification; JOA = Japanese Orthopaedic Association; OPLL = ossification of the posterior longitudinal ligament; ROM = range of motion; VAS = visual analog scale; cervical disc arthroplasty; heterotopic ossification