engleski

Axial vs. angular dynamization of anterior cervical fusion implants

Aim. To compare speed and quality of fusion following fixation with the first generation cervical plate and dynamic fixation system in surgical treatment of spondylogenic radiculomyelopathy. Methods. An independent matched-cohort study was conducted in two groups of patients: a trial (Dynamic fixation) group monitored prospectively and a control (“ H” plate) group of previously treated patients. Patients were matched by sex, age and number of operated levels. There were 10 patients in the one-level group, 8 in the two-level, and 5 in the multi-level group. The rotation and translation of screws, quality of fusion, and hardware position were assessed by two independent investigators. Statistical analysis was made using the Student test for independent samples and Fischer exact test. Results. Both groups consisted of 15 males and 8 females. Dynamization was detected in both groups: axial in the trial group (mean translation &plusmn ; ; SD = 2.67mm &plusmn ; ; 0.79 mm), and angular in the control group (angle of rotation 7.2° &plusmn ; ; 3.04°). In the one- level group, the mean angle was 4.8 &plusmn ; ; 1.14, in the two- level group 8, 37 &plusmn ; ; 1, 85 and in the multilevel group 8.4 &plusmn ; ; 2.3. A significant increase in the angle of rotation was noticed comparing the one-level and two-level group (p=0.0048). There was no significant difference between the angles in the two-level and multilevel group (p=0.643). The follow-up examination after 6 weeks showed that fusion was significantly better in the trial group (1.53 vs. 2.18 ; p=0.0013). There were 2 pseudoarthroses and 1 delayed union in the multilevel subgroup of the control group of patients. Four patients in the trial group had heterotopic ossification in the adjacent segment with ankylosis in 2 patients. Three of them had migration of allenthesis over adjacent intervertebral space. Conclusion. Our results suggest that subsidence was allowed with both fixation systems, but fusion was faster and more effective in the axially dynamised group. According to our results, angular dynamization stops after two level fusion and may be connected with pseudoarthrosis and delayed union in multilevel subgroup of the control group of patients.

surgical procedure; anterior; cervical plate; myelopathy; decompression; cervical fusion

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