Expansive laminoplasty as a method for managing cervical multilevel spondylotic myelopathy.

摘要

STUDY DESIGN: This study evaluated 12 patients with multilevel cervical spondylotic myelopathy who underwent Kurokawa's procedure using hydroxyapatite spacers and performed with T-saw thread wire. OBJECTIVES: To assess the efficacy and safety of Kurokawa's laminoplasty for patients with multilevel cervical spondylotic myelopathy using the T-saw, and to determine the radiographic and clinical factors that correlate with the prognosis. SUMMARY OF BACKGROUND DATA: Spinous process-splitting laminoplasty as an alternative or a combined method with an anterior approach was evaluated for the management of multilevel stenosis of the cervical spine. METHODS: This study involved 12 patients (10 men and 2 women) with multilevel spondylotic myelopathy managed with expansive laminoplasty using the T-saw to open the spinous process. The mean age of the patients was 56 years. The mean postoperative follow-up period was 2 years. Magnetic resonance imaging and computed tomography scan were performed for all the patients. Clinical status and mobility after surgery also were evaluated. The average duration of symptoms was 3 years (range, 3 months to 5 years). RESULTS: Nine patients had five levels of decompression (C3-C7), and three patients had four levels of decompression: C3-C6 (2 patients) and C4-C7 (1 patient). The mean duration of surgery was 3 hours. No cases of postoperative kyphosis, instability, or neurologic deficit were found. All the patients had a decrease of at least one level. The mean Nurick Functional Disability Score improved from 2.8 (range, 2-4) before surgery to 1.2 (range 1-3) after surgery. Verification of the canal expansion was measured using the increase of the spinal canal-vertebral body ratio at each level from C3 to C7 in nine patients, from C3 to C6 in two patients, and from C4 to C7 in one patient. After surgery, it was possible to make a comparison by measuring the osseous canal directly with computed tomography scans and high-resolution magnetic resonance imaging. The levels of myelomalacia assessed by magnetic resonance imaging in all the patients was 2.5 before surgery, and less than one level (range, 0-2) thereafter, the posterior movement of the spinal cord in all the patients at level C5 being 1.2 mm. At the latest follow-up evaluation, cervical motion assessed by plain radiographs in flexion and extension, both before and after surgery, decreased 29% (range, 25-32%). CONCLUSIONS: Laminoplasty with the T-saw technique appears to be a good method for managing multilevel cervical spondylotic myelopathy. This method is associated with a low rate of complications that also allows marked functional improvement in most patients. It can be used as a complement to anterior surgery.