Radiological and clinical outcomes of 3-level cervical disc arthroplasty

One- and two-level cervical disc arthroplasty (CDA) has been compared to anterior cervical discectomy and fusion (ACDF) in several large-scale, prospective, randomized trials that have demonstrated similar clinical outcomes. However, whether these results would be similar when treating 3-level disc herniation and/or spondylosis has remained unanswered. This study aimed to investigate the differences between 3-level CDA and ACDF.

A series of 50 patients who underwent 3-level CDA at C3-7 was retrospectively reviewed and compared with another series of 50 patients (age- and sex-matched controls) who underwent ACDF at C3-7. Clinical outcomes were measured using the visual analog scale (VAS) for neck and arm pain, the modified Japanese Orthopaedic Association (mJOA) scale, and the Neck Disability Index (NDI). Radiological outcomes included range of motion (ROM) at the index levels. Every patient was evaluated by CT for the presence of fusion in the ACDF group. Also, complication profiles were investigated.

The demographics and levels of distribution in both groups were very similar. During the follow-up period of 24 months, clinical outcomes improved (overall and respectively in each group) for both the CDA and ACDF patients when compared with the patients' preoperative condition. There were essentially few differences between the two groups in terms of neck and arm pain VAS scores, mJOA scores, and NDI scores preoperatively and at 3, 6, 12, and 24 months postoperatively. After the 3-level surgery, the CDA group had an increased mean ROM of approximately 3.4°, at 25.2° ± 8.84°, compared to their preoperative ROM (21.8° ± 7.20°) (p = 0.001), whereas the ACDF group had little mobility (22.8° ± 5.90° before and 1.0° ± 1.28° after surgery; p < 0.001). The mean operative time, estimated blood loss, and complication profiles were similar for both groups.

In this selectively matched retrospective study, clinical outcomes after 3-level CDA and ACDF were similar during the 2-year follow-up period. CDA not only successfully preserved but slightly increased the mobility at the 3 index levels. However, the safety and efficacy of 3-level CDA requires more long-term data for validatation.