[Anterior segmental decompression and double-plate fixation for treatment of skip cervical spondylotic myelopathy].

OBJECTIVE

To evaluate the clinical outcomes and values of anterior segmental decompression and double-plate fixation (ASDDF) for treatment of skip cervical spondylotic myelopathy (SCSM).

METHODS

Between June 2005 and June 2008, 17 patients with SCSM were treated with ASDDF. There were 10 males and 7 females with an average age of 58.8 years (range, 41-74 years) and an average disease duration of 9.7 months (range, 6-39 months). According to Japanese Orthopaedic Association (JOA) score system, 2 patients were rated as extreme severe condition, 7 as severe, 7 as moderate, and 1 as mild. MRI images showed 42 affected cervical disc levels, including 26 disc levels with high-intensity intramedullary lesions on T2, 4 with low-intensity intramedullary lesions on T1, and 12 with significant cord compression but no signal change; according to Nagata classification scale, there were 5 abnormal segments at class I, 21 at class II, and 16 at class III. The rate of fusion, the Cobb angle, and the range of motion (ROM) of the cervical spine were measured preoperatively and postoperatively by the X-ray examinations. The improvement of the neurological function was evaluated by the JOA score.

RESULTS

The average time of follow-up was 28.6 months (range, 24-58 months). After operation, dysphagia occurred in 2 cases (symptom relief after 1 month), hoarseness in 1 case (symptom relief after 3 months of methylcobalamin treatment), and degeneration of adjacent segments without symptom in 3 cases. The X-ray films showed the fusion rate of 100% at 12 months after operation without displacement, resorption or collapse of bone graft, and without breakage or loosening of plate and screw. The Cobb angles were (13.3 +/- 10.4) degrees preoperatively, (15.8 +/- 10.8) degrees immediately postoperatively, and (15.4 +/- 11.4) degrees at last follow-up; the ROM of the cervical spine were (41.3 +/- 17.4) degrees preoperatively and (23.8 +/- 18.8) degrees at last follow-up; and the JOA scores were 8.2 +/- 2.9 preoperatively, 13.7 +/- 3.0 at 12 months postoperatively, and 13.9 +/- 2.8 at last follow-up. All indexes showed significant differences between before operation and after operation (P < 0.05). The results of JOA scores were excellent in 8 cases, good in 6, fair in 2, and poor in 1 with an average improvement rate of 66.8% (range, 14%-88%) for the neurological function.

CONCLUSION

Adequate decompression, high rate of fusion, solid mechanical stability, improvement of total cervical lordosis, and the neurological function can be achieved through ASDDF for treatment of SCSM.