Comparison of the long-term clinical effects between single-level Discover artificial cervical disc replacement and anterior cervical decompression and fusion in the treatment of cervical spondylosis

English Keywords:Cervical spondylosis  Artificial cervical disc replacement  Anterior cervical discectomy and fusion  Long-term follow-up  Clinical efficacy

English Abstract:

  【Abstract】 Objectives： To evaluate the long-term clinical efficacies of single-level Discover artificial cervical disc replacement(ACDR) and anterior cervical discectomy and fusion(ACDF) in the treatment of cervical spondylosis. Methods: The clinical data of patients with cervical spondylosis who underwent single-level ACDR or ACDF in Xijing Hospital from January 2009 to December 2011 were reviewed. ACDR group consisted of 21 patients(15 males and 6 females), aged 44.0±7.5(33-58) years old and treated with Discover prosthesis, involving C4/5 in 2 cases, C5/6 in 17 cases, and C6/7 in 2 cases. ACDF group consisted of 25 patients(20 males and 5 females), aged 48.2±8.5(33-63) years old, involving C3/4 in 1 case, C4/5 in 3 cases, C5/6 in 18 cases, and C6/7 in 3 cases. Japanese Orthopedic Association(JOA) score, visual analogue scale(VAS) and neck disability index(NDI) were used to assess the patients′ neurological functions and the clinical effects before surgery, at 3 months after surgery, and 1, 2, and 5 years after surgery, as well as the last follow-up. The range of motion(ROM) at the index level of ACDR group and final follow-up heterotopic ossification(HO) of ACDR group and adjacent segments degeneration(ASD) conditions of both groups were measured and evaluated with cervical spinal radiographs, CT scan and MRI, and statistical analyses were performed. Results: The mean follow-up time was 138.9±12.0 months in ACDR group and 136.9±10.8 months in ACDF group, and there was no statistical difference between the two groups(P>0.05). The postoperative follow-up JOA, VAS-Arm, and VAS-Neck scores and NDI of the two groups were all significantly improved compared with those before operation(P<0.05), respectively, there was no statistical difference between the scores at the last follow-up and 2 years after surgery in the same group(P>0.05), and there was no statistical difference between the two groups at the same time point(P>0.05). In the ACDR group, the range of motion(ROM) at the index level at the 3 month, 1 year and 2 years after surgery was significantly improved compared with that before surgery(P<0.05), and which at postoperative 5 years and final follow-up was not statistically different from that before operation(P>0.05). At the final follow-up, 13 cases(61.9%) in ACDR group occurred HO at the operated level, of which 1 case was of grade Ⅰ, 3 cases of grade Ⅱ, 6 cases of grade Ⅱ, and 3 cases of grade Ⅳ according to McAfee′s classification. The ASD rate in ACDR group(17/42, 40.5%) and ACDF group(34/50, 68.0%) was statistically different(P<0.05). At the last follow-up, there were 0 case of secondary operation in ACDR group and 2 cases in ACDF group caused by ASD were in need of secondary operations. The secondary operation rate between groups was statistically different(0 vs 8%, P<0.05). Conclusions: Single-level ACDR has the same and good long-term clinical efficacy comparing with ACDF, which also superiors in reducing the incidence of ASD in the treatment of cervical spondylosis. However, the incidence of HO at the index level may gradually increase over time, resulting in the reduction of the ROM at the index level.