RESUMO
OBJECTIVE: Anterior cervical discectomy and fusion (ACDF) is a standard surgical approach for cervical spondylotic myelopathy (CSM) caused by disc herniations. Although cervical disc arthroplasty (CDA) has become, in the past decade, a viable alternative to ACDF in selected patients, the differences among patients with CSM treated with CDA and ACDF remain elusive. The effectiveness of motion preservation devices in CSM is also unclear. METHODS: Adult patients who underwent 1- or 2-level CDA or ACDF between 2007 and 2021 were retrospectively reviewed. Patients whose preoperative T2-weighted MRI demonstrated increased intramedullary signal intensity (IISI) were included and analyzed for the following: comparison of the length of IISI on pre- and postoperative MR images as well as range of motion (ROM) at the indexed levels between the CDA and ACDF groups. Measurement for clinical outcomes included the visual analog scale (VAS) of the arm and neck, the Neck Disability Index, and modified Japanese Orthopaedic Association scores. Perioperative clinical data were also compared between the two groups. RESULTS: A total of 122 patients were allocated to the CDA group and 108 to the ACDF group, with mean follow-ups of 46.6 and 39.0 months, respectively. Patients in the CDA group were younger than those in the ACDF group (47.64 ± 12.40 vs 61.73 ± 12.25 years, p < 0.001) (mean ± SD). The ACDF group had more 2-level surgery compared to the CDA group (p = 0.002). Both groups had significant regression of IISI on postoperative MRI compared to that of preoperative imaging (CDA: 1.23 ± 0.84 to 0.28 ± 0.39 cm; ACDF: 1.07 ± 0.60 to 0.37 ± 0.42 cm; both p < 0.001). The decrease in the length of IISI was similar between the two groups (p = 0.058). The postoperative ROM was well preserved in the CDA group (superior to ACDF, which yielded minimal ROM postoperatively). Both the CDA and ACDF groups demonstrated improvement in Neck Disability Index and modified Japanese Orthopaedic Association scores at 24 months postoperatively. The CDA group had significant improvements on VAS scores, whereas the improvement did not reach significance for the ACDF group at 24 months postoperatively. CONCLUSIONS: Significant shortening of IISI on T2-weighted MRI was demonstrated after both CDA and ACDF. At 24 months postoperatively, all clinical outcomes demonstrated improvement after both strategies, except that the VAS score was not significantly improved for ACDF. Therefore, CDA is a safe and effective option for patients with MR-evident CSM.
RESUMO
OBJECTIVE: Several trials from the U.S. Food and Drug Administration have demonstrated the success of cervical disc arthroplasty (CDA) in patients with degenerative disc disease causing radiculopathy, myelopathy, or both. For patients who had increased intramedullary signal intensity (IISI) on magnetic resonance image (MRI), however, the effectiveness and safety of CDA was unclear. This study aimed to evaluate the outcomes of CDA for patients with IISI on preoperative MRI. METHODS: Consecutive patients who received 1-level CDA for symptomatic degenerative disc disease were reviewed retrospectively. Patients with IISI on preoperative T2-weighted MRI were compared to those without IISI (non-IISI). Clinical outcome parameters including visual analog scale, Neck Disability Index, Japanese Orthopedic Association (JOA), and Nurick scores were analyzed. Radiographic studies included dynamic lateral radiography and MRI. RESULTS: A total of 91 patients were analyzed (22 in the IISI group and 69 in the non-IISI group). The mean follow-up was 30.0 months. The demographic data were mostly similar between the 2 groups. All clinical outcomes, including visual analog scale, Neck Disability Index, JOA, and Nurick scores in the IISI group demonstrated significant improvement after operation. The IISI group had similar clinical outcomes to the non-IISI group, except that the JOA scores were generally worse. Follow-up MRI demonstrated significant regression of the length of IISI (P = 0.009). Both groups had preserved motion after CDA. CONCLUSIONS: Both clinical and radiological outcomes improved (the average length of IISI in the cervical spinal cord became shorter) after CDA. Therefore, CDA is a safe and effective option for patients even when there is IISI on the preoperative T2-weighted MRI.