Comparisons of three anterior cervical surgeries in treating cervical spondylotic myelopathy
© Zhu et al.; licensee BioMed Central Ltd. 2014
Received: 30 June 2013
Accepted: 3 July 2014
Published: 10 July 2014
Anterior cervical discectomy and fusion (ACDF) was one of the preferred treatments for degenerative cervical spondylosis. However, the motion of adjacent segment was significantly increased after operation. So cervical disc arthroplasty have been suggested to keep the motion of adjacent segment. A new implant named dynamic cervical implant (DCI) has been developed to keep the motion of adjacent segment.
We retrospectively reviewed 91 patients treated for single level cervical spondylotic myelopathy with anterior cervical discectomy and fusion (ACDF), dynamic cervical implant (DCI) and cervical total disc replacement (CTDR) between sep 2009 and Mar 2011 in our hospital. They were divided into three groups by surgical methods: ACDF group (group A, 34 cases), DCI group (group B, 25 cases), CTDR group (group C, 32 cases). Operation time, intraoperative blood loss, preoperative and postoperative JOA score and JOA recovery rate were compared among the three groups. Pre-and postoperative hyperextension and hyperflexion radiograms were observed to measure range of motion (ROM) of C2–7, operative and adjacent levels.
There was no statistical difference in operative time, intraoperative blood loss, and JOA recovery rate (P > 0.05) among three groups. But the differences of their postoperative JOA scores and preoperative JOA scores were of statistical significance (P < 0.05). Compared the pre-and postoperative ROM of C2–7, operative, upper and lower levels of each group respectively, the difference between preoperative ROM and postoperative ROM of group A were of statistically significant (P < 0.05), while was no statistically significant of group C (P > 0.05). There was no statistically significant difference between preoperative ROM and postoperative ROM of upper and lower levels in group B (P > 0.05), but had statistically significance of C2–7 and operative levels (P < 0.05).
Three operations are effective therapies for single level cervical spondylotic myelopathy. But each group has respective advantages and disadvantages.
KeywordsCervical spondylotic myelopathy Fusion Non-fusion Dynamic cervical implant Clinical effects
Since 1950s, anterior cervical discectomy and fusion (ACDF) has been considered as the golden standard of treating middle-aged degenerative cervical spondylosis[1, 2]. But as is found in long-term clinical researches, the motion of cervical spine might decrease after ACDF, while fused adjacent segments accelerate degeneration[3–5]. Cervical total disc replacement can maintain the motion of surgical segments as well as the cervical stability, however, it has a high incidence of Heterotopic Ossification and kyphosis with few indications. Dynamic cervical implant (DCI) is a U-shaped titanium alloy stabilizing device for cervical implantation recently designed by GCI, which provides cervical dynamic stability under non-fusion. This research compares the curative effects and ROM of C2–7, operative, upper and lower levels of three anterior approaches in treating single level cervical spondylotic myelopathy.
91 cases of single level cervical spondylotic myelopathy diagnosed and followed up in our hospital from September 2009 to March 2011 were conducted among people who underwent the examination of anteroposterior, lateral, hyperextension and hyperflexion X-rays, CT scan and MRI. Among them, 34 cases underwent anterior cervical discectomy and fusion with traditional titanium plate and Cage (Group A), and the devices were ATLANTIS titanium plate and PEEK CornerStone-SR cage provided by Medtronic. There were 16 females and 18 males with an average age of 49.54 years (range 32–69 y) at surgery. The average duration of symptoms was 10.75 months (range 1–55 months). Postoperative follow-up was 13–32 months, with an average time of 20.33 months. C3–4 2 cases, C4–5 9 cases, C5–6 14 cases, C6–7 9 cases. 25 cases underwent DCI implantation (Group B), and the devices were the DCI of GCI. There were 11 females and 14 males with an average age of 47.07 years (range 23-62y) at surgery. The average duration of symptoms was 11.13 months (range 2–50 months). Postoperative follow-up was 14–33 months with an average follow-up was 19.93 months. C3–4 2 cases, C4–5 7 cases, C5–6 11 cases, C6–7 5 cases. 32 cases underwent cervical total disc replacement with prestige prosthesis (Group C), and the device was provided by Medtronic. There were 12 females and 10 males with an average age of 48.00 years (range 34-67 y) at surgery. The average duration of symptoms was 10.63 months (range 2-60 months). Postoperative follow-up was 12–30 months with an average follow-up of 20.18 months. C3–4 1 cases, C4–5 6 cases, C5–6 15 cases, C6–7 10 cases. There was no statistical difference in age, follow-up time and duration of symptoms among the three groups (P > 0.05). This study was approved by the Institutional Ethics Committee of Soochow University.
All surgeries were conducted by a chief physician of our hospital. After cervical plexus anesthesia or endotracheal intubation for general anaesthesia, the patients were placed with ahead extension in supine position. Group A: The operations were performed using standard anterior cervical discectomy and fusion. Group B and C: A transverse incision is made in a skin crease at the appropriate disc level on the right side of the neck. After confirmation and exposure of the appropriate vertebral levels. The Casper distracter was placed and the disc materials were removed and the resection of posterior longitudinal ligament was applied depending on the pressurized severity of dural sac. Group B: After decompression, model testing was conducted with DCI specific tool under fluoroscopy, placing corresponding DCI model in intervertebral space. The insertion depth was 2-3 cm away from the vertebral body. As the position was observed to be satisfying under fluoroscopy with C-arm X-ray machine, and then conventionally close the incision. Group C: After decompression, we put the tested models into intervertebral space to get appropriate prosthesis, and used different models of files to polish the endplate as flat as possible and keep its cortical bone, to get filing marks on the bone plate, as well as appropriate intervertebral space. Guided by pilot sleeve, gently knock out a groove separately on upper and lower endplates for prosthesis implantation, implanted the prestige prosthesis into intervertebral space. As the position was observed to be satisfying under fluoroscopy with C-arm X-ray machine, and then conventionally close the incision. The operation time and the intraoperative blood loss for the three groups were recorded.
Clinical outcome assessment
Follow-up clinical examinations were obtained by a physician unrelated to the surgical procedures. The clinical outcomes were evaluated using Japanese Orthopaedic Association (JOA) score before and after operations. A recovery rate (RR) was also calculated, which was defined according to the rationale of Hirabayashi et al. as RR = (postoperative JOA scores- preoperative JOA scores)/(17- preoperative JOA scores) × 100%. Results were indicated by the RR as follows: 75% or more (excellent), 50% to 74% (good), 25% to 49% (fair), and less than 25% (poor). The patients’ conditions were divided into three levels and indicated by the JOA scores as follows: less than 7 score (severe), 8 score to 12 score (moderate), 13 score to 16 scores (Mild).
All follow-up patients underwent anteroposterior, lateral, hyperextension and hyperflexion X-rays, the range of motion (ROM) of C2–7, operative and adjacent levels were measured on hyperextension and hyperflexion radiograms according to the Cobb’ method. The imaging data were separately and independently measured blindedly by three orthopaedics physician, the results were mean value.
A Paired- samples t test was used for the paired data and an One-Way ANOVA was used for Three-samples data. The two-tailed test ’s results were considered significant when P was less than 0.05. All the analyses were performed using Microsoft Excel 2003 (Microsoft, Seattle, WA) and SPSS 16.0 (SPSS, Chicago, IL,USA).
Comparisons of intraoperative blood loss, operative time and JOA scores among three groups
Intraoperative blood loss
Preoperative JOA score
Postoperative JOA score
JOA recovey rate
94.79 ± 14.33
109.79 ± 18.97
9.54 ± 0.88*
13.96 ± 1.52*
0.60 ± 0.18
93.33 ± 13.05
125.00 ± 18.13
9.33 ± 1.18*
14.07 ± 1.79*
0.62 ± 0.21
91.59 ± 15.77
116.59 ± 20.49
9.27 ± 0.83*
14.00 ± 1.19*
0.62 ± 0.16
Sagittal ROM of C 2-7 , implanted level and adjacent levels
49.92 ± 8.17
49.13 ± 8.04
49.18 ± 7.82
41.08 ± 4.74
44.73 ± 6.90
48.59 ± 6.80
Implanted level ROM
8.88 ± 1.33
9.20 ± 1.26
8.91 ± 1.48
7.13 ± 1.19
8.59 ± 1.68
Upper level ROM
8.83 ± 1.83
8.87 ± 1.46
9.05 ± 1.86
10.75 ± 1.82
9.33 ± 2.72
9.23 ± 2.52
Lower level ROM
9.04 ± 1.46
8.93 ± 1.90
9.27 ± 1.75
11.08 ± 1.56
9.80 ± 2.51
9.45 ± 2.22
Cervical spondylotic myelopathy is a common disease endangering human beings. When the patients have failed formal conservative treatment and worsened syndromes, he should undergo surgery. All surgical treatments achieve effects by discectomy for relieving spinal cord compression, and what differs is the approach which is typical fusion or cervical arthroplasty that emphasizes on maintaining the motion of surgical segments in recent years. In 1958, Robinson, Smith and Cloward successively adopted ACDF to treat cervical spondylosis caused by intervertebral disc degeneration with good clinical effects, so it became the typical surgical method to treat cervical spondylosis. However, as is found in numerous long-term clinical cases, ACDF has some complications like reduced cervical activity and accelerated degeneration of adjacent-segment disc. After as long as 21 years follow-up of 374 cases undergoing ACDF, Hilibrand et al. found that the clinical syndromes caused by fusion adjacent segment degeneration had an average incidence of 2.9% in postoperative 10 years, which requires clinical focus and in-depth research.
Dynamic cervical implant size (mm)
Size (length × width)
10 × 12
12 × 14
14 × 16
16 × 18
10 × 12
12 × 14
14 × 16
16 × 18
10 × 12
12 × 14
14 × 16
16 × 18
The three anterior cervical surgical approaches have good curative effects on single level cervical spondylotic myelopathy. Both anterior fusion and cervical total disc replacement have their own advantages and disadvantages, and DCI implantation, as a new non-fusion approach, is easy and simple to operate with short learning curve. It is an interbody fixed device between ACDF and cervical disc replacement surgery, being able to partially keep the motion function of cervical surgical segments and an new alternative of treating cervical spondylosis. Although its short-term effect is satisfactory, it has a short follow-up time and few cases. Whether DCI prosthesis will be loose, fall off or submerge, whether heterotopic Ossification occurs around DCI prosthesis and what are the middle and long-term curative effects require a long follow-up.
No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
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