ObjectiveTo evaluate the long-term efficacy and influencing factors of cervical artificial disc replacement (CADR) for patients with cervical spondylotic radiculopathy (CSR).MethodsThe data of 29 CSR patients who underwent Bryan artificial disc replacement between December 2003 and December 2007 and followed up more than 10 years were retrospectively analysed. There were 16 males and 13 females with an average age of 54.1 years (range, 40-70 years). The disease duration was 2-144 months (mean, 19.2 months). CT and MRI were performed before operation to identify the compression segments (C3, 4 in 2 cases, C4, 5 in 6 cases, C5, 6 in 18 cases, C6, 7 in 3 cases) and the compression factors. According to the compression factor, the patients were divided into 2 groups: 14 patients with cervical disc herniation were in the group A and 15 patients combined with osteophyte were in the group B. There was no significant difference in gender, age, disease duration, and compressed level between 2 groups (P>0.05). The radiographic and clinical evaluation indexes were recorded before operation and at last follow-up. The radiographic evaluation indexes included the global cervical and segmental range of motion (ROM), loss of ROM (ROM<3°) at last follow-up, Cobb angle and incidence of local kyphosis, paravertebral ossification (PO) grading. The clinical evaluation indexes included neck disability index (NDI) and overall efficacy (Odom’s score).ResultsAll patients were followed up 121-153 months (mean, 130 months). The results of radiographic evaluation indexes showed that within group comparison, except that the Cobb angle of the operated level was significantly decreased (P<0.05) in both 2 groups, there was no significant difference in global cervical ROM and segmental ROM between preoperation and last follow-up (P>0.05). Except that the loss of ROM (ROM<3°) at last follow-up and high-grade PO at last follow-up in group B were significantly higher than those in group A (P<0.05), there was no significant difference in other radiographic evaluation indexes between 2 groups (P>0.05). The results of clinical evaluation indexes showed that the NDI was significantly improved in both groups (P<0.05) at last follow-up. There was no significant difference in the NDI at preoperation and at last follow-up, the decline of NDI at last follow-up, and the overall efficacy evaluated by Odom’s score between 2 groups (P>0.05). The excellent and good rate of overall efficacy reached 100% in both groups.ConclusionCADR has satisfied long-term efficacy in treating CSR. The maintenance of segmental mobility was better in patients with disc herniation than in patients with disc herniation and osteophyte.
ObjectiveTo evaluate the influence of the shell angle of cervical artificial disc on long-term effectiveness of cervical artificial disc replacement (CADR).MethodsThe clinical data of 71 patients who were treated with single-level CADR with Bryan prosthesis between December 2003 and December 2007 and followed up more than 10 years, were retrospectively analyzed. There were 44 males and 27 females with an age of 26-69 years (mean, 45.9 years). According to the shell angle of the cervical artificial disc which was measured on the postoperative lateral X-ray film, the patients were divided into kyphotic group (shell angle was negative) and non-kyphotic group. The following evaluation indexes before operation and at last follow-up were compared between 2 groups. Radiographic indexes included the range of motion (ROM) of cervical spine, the ROM of operated level, Cobb angle of operated level (the negative value indicated that the segmental kyphosis occurred at operated level), paravertebral ossification (PO) grades (grades 3 and 4 were high grade PO). Clinical indexes included Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), and overall effectiveness evaluation (Odom criteria).ResultsThere were 24 patients in kyphotic group and 47 patients in non-kyphotic group. There was no significant difference in baseline data including gender, age, and operated level between 2 groups (P>0.05). All the patients in 2 groups were followed up 121-165 months (mean, 128 months). There was no significant difference in preoperative ROM of cervical spine and ROM of operated level between 2 groups (P>0.05); but the preoperative Cobb angle of operated level in kyphosis group was significantly lower than that in non-kyphotic group (t=2.636, P=0.013). There was no significant difference in ROM of cervical spine at last follow-up between 2 groups (t=1.393, P=0.168), however, the ROM and the Cobb angle of operated level in kyphotic group were significantly lower than those in non-kyphotic group (P<0.05). According to the Cobb angle of operated level at last follow-up, there were 9 patients (37.5%) with segmental kyphosis in kyphotic group and 7 patients (14.9%) in non-kyphotic group, showing significant difference (χ2=4.651, P=0.031). There was a significant difference in PO grades between 2 groups (Z=2.894, P=0.004) at last follow-up. In kyphotic group, there were 10 patients (41.7%) with low grade PO and 14 patients (58.3%) with high grade PO; and in non-kyphosis group, there were 36 patients (76.6%) with low grade PO and 11 patients (23.4%) with high grade PO. There was no significant difference in JOA scores and NDI before operation and at last follow-up, and the JOA improvement rate, NDI decline, and Odom criteria score at last follow-up between 2 groups (P>0.05).ConclusionThe shell angle of cervical artificial disc may lead to a decrease in the postoperative segmental ROM, and an increased occurrence of segmental kyphosis and high incidence of PO.