Medium and long term result of the single level cervical disc arthroplasty for cervical spondylosis meylopathy

English Keywords:Cervical spondylosis  Cervical disc arthroplasty  Anterior cervical decompression and fusion  Outcome  Medium and long term

English Abstract:

  【Abstract】 Objectives: To investigate the medium and long term clinical outcome of the single level cervical disc arthroplasty(CDA) vs anterior cervical decompression and fusion(ACDF) in a randomized controlled study. Methods: The medium and long term clinical outcome of the single level Bryan prosthesis CDA(experimental group) and conventional ACDF(controlled group) was reviewed retrospectively. All the patients participated in a randomized controlled prospective study from 2003 to 2005, the inclusive criteria for cervical disc arthroplasty was used in 80 cases, and 32 patients was in CDA group and 35 patients in ACDF group finished the clinical and imaging follow-up(range, 7-9 years). The range of movement(ROM) in operation segement was determined by dynamic X-ray. The heterotopic ossification around the prosthesis was determined according to McAfee classification, the adjacent segment degeneration was verified according to Miyazaki classification on MRI T2 weighted images, and the symptom improvement was determined by NDI and VAS score. Results: The postoperative follow-up averaged 8.8 years, ranging from 7.2 to 9.6 years. No prosthesis displacement occurred in CDA group. Range of motion in CDA group averaged 6.35°±1.45°, ranging from 1.20° to 8.20°. The heterotopic ossification around the prosthesis was noted in 8 of 32(25%) segments, which induced loss of motion in 2 cases. 3 patients underwent the revision surgery due to 1 cranial adjacent segment degeneration and canal stenosis caused by ossification next to adjacent segment in 2 cases. The adjacent disc degeneration was noted as deterioration of 1 grade in 22 and 2 grade in 8 of the rest 63 segments, but remained asymptomatic. 3 patients underwent revision surgery in ACDF group, with cranial disc degeneration and neurological deficit in 2 and spinal cord compression due to caudal disc degeneration in 1. The adjacent disc degeneration was noted as deterioration of 1 grade in 34 and 2 grade in 15 of the rest 67 segments, but remained asymptomatic. The NDI, VAS score for neck and upper limb at final follow-up in CDA group was 16.83±3.12, 1.17±0.41 and 1.96±0.51 respectively; while in ACDF group, it was 17.21±3.53, 1.23±0.35 and 1.86±0.62 respectively. There was significant improvement compared with pre-operation, but no statistical difference between 2 groups(P＞0.05). Conclusions: No significant difference of medium and long term outcome exists between cervical disc arthroplasty and ACDF, while the former can maintain the ROM of involved segment as well as preventing ASD, which is optional for single level cervical spondylosis meylopathy.