【Abstract】 Objective To investigate the early effectiveness of the Discover cervical artificial disc replacement in treating cervical spondylosis. Methods Qualified for the selective standard, 24 patients with cervical spondylosis were treated between March 2010 and March 2011. Of 24 patients, 13 patients underwent anterior cervical decompression and fusion (ACDF) (ACDF group, between March 2010 and September 2010) and 11 patients underwent Discover cervical artificial disc replacement (CADR group, between September 2010 and March 2011). There was no significant difference in gender, age, disease duration, lesions typing, and affected segments between 2 groups (P gt; 0.05). The operative time, blood loss, and complications were recorded. Japanese Orthopaedic Association (JOA) scores, Neck Disability Index (NDI) scores, and Odom’s scores were used to evaluate the postoperative effectiveness. In CADR group, the cervical range of motion (ROM) in all directions, and prosthesis eccentricity were measured before and after operation. Results Symptoms disappeared and no complication occurred after operation in the patients of 2 groups. The patients were followed up 12 to 18 months (mean, 15.3 months) in ACDF group and 6 to 12 months (mean, 9.6 months) in CADR group. The NDI scores in CADR group were significantly higher than those in ACDF group at 1, 3, and 6 months (P lt; 0.05), but no significant difference was observed in JOA score improvement rate between 2 groups (P gt; 0.05). According to Odom’s score at last follow-up, the results were excellent in 6 cases, good in 4 cases, and fair in 3 cases with an excellent and good rate of 76.92% in ACDF group, and were excellent in 9 cases, good in 1 case, and poor in 1 case with an excellent and good rate of 90.91% in CADR group, showing no significant difference (χ2=3.000, P=0.223). The patients in CADR group had significant limit of cervical joint ROM in flexion and extension and right bending at 1 month (P lt; 0.05), but cervical joint ROM restored after 3 months. The ROMs of left bending at 3 months and 6 months were bigger than preoperative value (P lt; 0.05). Meanwhile, ROM in left bending were bigger than that in right bending in replaced segment and upper segment (P lt; 0.05), and the ROM difference between left bending and right bending in upper segment was 2 times higher than that in the replaced segment; a marked linear correlation (P lt; 0.05) existed between the ROM difference and prosthesis eccentricity, and prosthesis bias had bigger ROM in lateral bending. Conclusion Discover cervical artificial disc replacement for treatment of cervical spondylosis can provide a good effectiveness and cervical postoperative movement function. As a new prosthesis, it has some merits such as simple operative steps and less complications.
Objective To evaluate the incidence of heterotopic ossification (HO) after single-level Bryan cervical artificial disc replacement, and to identify the relationship between HO and the effectiveness. Methods The cl inical data of 48 patients undergoing single-level Bryan cervical artificial disc replacement between October 2005 and October 2007 were reviewedretrospectively. There were 27 males and 21 females with an average age of 40.5 years (range, 33-51 years), including 8 cases of cervical myelopathy, 27 cases of nerve root cervical spondylosis, and 13 cases of mixed cervical spondylosis with an average disease duration of 10.3 months (range, 2-14 months). The involved segments included C3, 4 in 3 cases, C4, 5 in 6 cases, C5, 6 in 30 cases, and C6, 7 in 9 cases. The outcomes were evaluated using Visual Analogue Scale (VAS) score, the neck disabil ity index (NDI), and cervical range of motion (ROM). According to patients with or without HO, 48 patients were divided into 2 groups (HO group and no HO group). VAS score, NDI, and cervical ROM were compared between 2 groups at 1, 2, 3, and 4 years after operation. Results No severe complication occurred during and after operation in all patients. Forty-eight patients were followed up 48-72 months (mean, 56.6 months). VAS score and NDI were significantly improved when compared with preoperative values at all time points (P lt; 0.05); except at 3 days after operation, no significant difference was found in cervical ROM at the other time points when compared with preoperation (P gt; 0.05). Thirteen patients (27.08%) had HO at 4 years after operation, including 8 cases of grade 1, 3 cases of grade 2, and 2 cases of grade 3. There was no significant difference in VAS score, NDI, and cervical ROM between 2 groups at 1, 2, 3, and 4 years (P gt; 0.05). Conclusion The incidence of HO after single-level Bryan cervical artificial disc replacement is relatively high. However, HO has no effect on the cervical ROM and the effectiveness.
Objective To investigate the cl inical effect of cervical artificial disc replacement (CADR) on twosegment cervical spondylosis and to research its influences on the range of motion (ROM) of the diseased segments and theadjacent superior and inferior segments. Methods From September 2004 to February 2007, 7 cases with cervical spondylosis at C4,5 and C5,6 were treated with CADR using Bryan artificial disc prosthesis, including 4 males and 3 females aged 30-45 years old (average 38.5 years old). All the patients had cervicodynia in various degrees, pain and numbness of l imbs and decreased muscle strength, including 3 cases of cervical spondylotic radiculopathy, 3 of cervical spondylotic myelopathy and 1 of mixed cervical spondylosis. The course of disease was 12-54 months (average 27 months). Preoperatively, X-ray films revealed the intervertebral space of C4, 5 and C5,6 was narrowed and the cervical curve became straight, CT or MRI showed the intervertebral disk hernia of C4, 5 and C5,6, and the hyperostosis of vertebral margin compressed nerve root or spinal cord. All the patients had no response to the preopratively conservative treatment. JOA score and ROM of the diseased segments and the adjacent superior and inferior segments were compared before and after operation. Results All the patients survived the perioperative period, without hoarse voice, muscle spasm, dysphagia and cervicodynia. X-ray films showed the implanted prosthesis was well located, the height of intervertebral space was normal, and no prosthesis loosening, prosthesis migration and infection occurred 12 months after operation. All the 7 cases were followed up for 12-41 months (average 26.7 months). Cervicodynia and l imbs’pain and numbness disappeared, and muscle strength was improved obviously. The JOA score before and during the followup period was (8.35 ± 1.27) and (14.65 ± 1.61) points, respectively, indicating there was a significant difference (P lt; 0.05). For the ROM of C4,5 and C5,6, it was (8.38 ± 0.48)° and (9.16 ± 0.54)° before operation, respectively, and it increased to (11.15 ± 0.65)° and (12.75 ± 0.73)° after operation, respectively, showing there was a significant difference (P lt; 0.05). The ROM at C3,4 and C6,7 before operation was (9.71 ± 0.76)° and (12.39 ± 0.58)°, espectively, while it was improved to (10.26 ± 0.47)° and (13.67 ± 0.71)° after operation, respectively, indicating there were no significant differences between before and after operation (P gt; 0.05). Conclusion The appl ication of Bryan Disc CADR for two-segment cervical spondylosis has satisfying therapeutic effects, can improve the ROM of diseased segments obviously, and has minor influences on the ROM of adjacent superior and inferior segment.
This study was aimed to estimate the effect of different ProDisc-C arthroplasty designs after it was implanted to C5-C6 cervicalspine. Finite element (FE) model of intact C5-C6 segments including the vertebrae and disc was developed and validated. Ball-and-socket artificial disc prosthesis model (ProDisc-C, Synthes) was implanted into the validated FE model and the curvature of the ProDisc-C prosthesis was varied. All models were loaded with compressed force 74 N and the pure moment of 1.8 Nm along flexion-extension and bilateral bending and axial torsion separately. The results indicated that the variation in the curvature of ball and socket configuration would influence the range of motion in flexion/extension, while there were not apparently differences under other conditions of loads. The method increasing the curvature will solve the stress concentration of the polyethylene, but it will also bring adverse outcomes, such as facet joint force increasing and ligament tension increasing. Therefore, the design of artificial discs should be considered comprehensively to reserve the range of motion as well as to avoid the adverse problems, so as not to affect the long-term clinical results.
Objective To observe the early effectiveness of cervical disc replacement with Pretic-I, a new type artificial disc. Methods A retrospective analysis was made on the clinical data of 10 patients who underwent single segmental cervical disc replacement with Pretic-I from June to December 2014. Among 10 patients, 4 were male and 6 were female, with an average age of 40 years (range, 27-51 years). The mean disease duration was 15.4 months (range, 4-36 months). Affected segments located at C4, 5 level in 1 case, at C5, 6 level in 8 cases, and at C6, 7 level in 1 case. The visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) score, and neck disability index (NDI) were used to evaluate the clinical outcomes. Besides, the disc height and the range of motion (ROM) at operated level, and ROM of upper and lower adjacent level were measured to assess the function. Results The operation was successfully completed in all patients who were followed up for 12 months. No complications of aggravated nerve symptoms, vertebral artery injury, esophagotracheal fistula, cerebrospinal fluid leakage, incision infection, hematoma and prosthetic loosening were observed during follow-up. The VAS score, JOA score, and NDI significantly improved at each time point after operation when compared with preoperative scores (P<0.05). The height of intervertebral disc at operated level was significantly increased at immediate and 3 months after operation when compared with preoperative one (P<0.05), but no significant difference was found between at 6 months or 12 months after operation and at pre-operation (P>0.05). No significant difference was shown in the ROM at operated level, and ROM of upper and lower adjacent level between at pre-operation and at each time point after operation (P>0.05). Conclusion The early effctiveness of cervical disc replacement using Pretic-I is satisfactory. The symptoms can be relieved significantly and the dynamic features of the operated level, as well as the upper and lower adjacent levels, are well preserved.
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.
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.
Anterior cervical decompression and fusion (ACDF) treatment for cervical spondylosis has been more than half a century, and achieved good clinical results. However, with the continuous extension of follow-up time, the fusion segment-associated postoperative complications emerged gradually. Reserved cervical stability and activity, the concept of non-fusion was born. As a non-fusion technique, cervical artificial disc replacement (CADR) developed rapidly. With the continuous development of artificial prosthesis materials and design concepts, and specification and proficiency of surgical procedures, CADR has achieved better short- and mid-term clinical efficacy than ACDF. Compared with ACDF, the main advantages of CADR are that the postoperative recovery is quick, the activity and stability of cervical vertebra are maintained, the height of cervical intervertebral space is restored, and the stress of adjacent segments and the rate of surgical renovation are reduced. In clinical work, as an emerging technology, CADR requires spine surgeons to control the surgical indications, contraindications, and patients’ conditions strictly. This article reviews the research progress of CADR in order to provide new ideas for clinical treatment of cervical spondylosis.
Objective To compare the short-term effectiveness and the impact on cervical segmental range of motion using Prodisc-C Vivo artificial disc replacement and Zero-P fusion for the treatment of single-segment cervical spondylosis. MethodsThe clinical data of 56 patients with single-segment cervical spondylosis who met the selection criteria between January 2015 and December 2018 were retrospectively analyzed, and they were divided into study group (27 cases, using Prodisc-C Vivo artificial disc replacement) and control group (29 cases, using Zero-P fusion) according to different surgical methods. There was no significant difference between the two groups in terms of gender, age, type of cervical spondylosis, disease duration, involved segments and preoperative pain visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), surgical segments range of motion, upper and lower adjacent segments range of motion, overall cervical spine range of motion, and cervical curvature (P>0.05). The operation time, intraoperative blood loss, postoperative hospitalization stay, time of returning to work, clinical effectiveness indicators (VAS score, JOA score, NDI, and improvement rate of each score), and imaging indicators (surgical segments range of motion, upper and lower adjacent segments range of motion, overall cervical spine range of motion, and cervical curvature, prosthesis position, bone absorption, heterotopic ossification, etc.) were recorded and compared between the two groups. ResultsThere was no significant difference in operation time and intraoperative blood loss between the two groups (P>0.05); the postoperative hospitalization stay and time of returning to work in the study group were significantly shorter than those in the control group (P<0.05). Both groups were followed up 12-64 months, with an average of 26 months. There was no complication such as limb or organ damage, implant failure, and severe degeneration of adjacent segments requiring reoperation. The VAS score, JOA score, and NDI of the two groups at each time point after operation significantly improved when compared with those before operation (P<0.05); there was no significant difference in the above scores at each time point after operation between the two groups (P>0.05); there was no significant difference in the improvement rate of each score between the two groups at last follow-up (P>0.05). The surgical segments range of motion in the study group maintained to varying degrees after operation, while it in the control group basically disappeared after operation, showing significant differences between the two groups (P<0.05). At last follow-up, there was no significant difference in the upper and lower adjacent segments range of motion in the study group when compared with preoperative ones (P>0.05), while the upper adjacent segments range of motion in the control group increased significantly (P<0.05). The overall cervical spine range of motion and cervical curvature of the two groups decreased at 3 months after operation, and increased to varying degrees at last follow-up, but there was no significant difference between groups and within groups (P>0.05). At last follow-up, X-ray films and CT examinations showed that no prosthesis loosening, subsidence, or displacement was found in all patients; there were 2 cases (7.4%) of periprosthetic bone resorption and 3 cases (11.1%) of heterotopic ossification which did not affect the surgical segments range of motion. ConclusionBoth the Prodisc-C Vivo artificial disc replacement and Zero-P fusion have satisfactory short-term effectiveness in treatment of single-segment cervical spondylosis. Prodisc-C Vivo artificial disc replacement can also maintain the cervical spine range of motion to a certain extent, while reducing the occurrence of excessive motion of adjacent segments after fusion.