T-Saw laminoplasty for the management of cervical spondylotic myelopathy: clinical and radiographic outcome

Abstract

Study design: Independent evaluation of 18 patients with multilevel cervical spondylotic myelopathy who underwent threadwire T-saw laminoplasty.

Objectives: Assess the efficacy of midline T-saw laminoplasty in non-Japanese patients based on clinical and radiographic criteria.

Summary of background data: Spinous process-splitting laminoplasty has been well accepted in Japan. The results in non-Japanese patients are unknown.

Methods: A single physician performed independent clinical and radiographic evaluations at latest follow-up (mean, 24 months). In addition to a patient self-assessment questionnaire, objective measures included physical examination, Pavlov's ratio, sagittal canal diameter (by computed tomography), cord compression index, cervical lordosis, range of motion, and complications.

Results: Progression of myelopathy was arrested in all patients. Patients reported improvement in strength (78%), dexterity (67%), numbness (83%), pain (83%), and gait (67%). Bowel and bladder compromise resolved in five of six patients. The mean Nurick score improved from 2.7 to 0.9 (P < 0.001), and the mean Robinson pain score improved from 2.0 to 0.89 (P = 0.002). No patient required narcotic analgesics at latest follow-up compared with eight before laminoplasty. Objectively, 68% of patients with motor weakness regained normal strength (P = 0.001), whereas 50% regained normal sensation (P = 0.003). Radiographic canal expansion was verified by a statistically significant increase in the mean Pavlov ratio and osseous sagittal computed tomographic measurements. The mean cord compression index improved from 0.49 to 0.61 (P = 0.01). There was no significant change in mean cervical lordosis. Graft dislodgment or segmental instability did not occur. Complications included: infection (n = 1) and persistent postoperative motor root lesion at C5 (n = 1).

Conclusions: T-saw laminoplasty appears to be a safe and effective method of arresting the progression of myelopathy and allowing marked functional improvement in most patients with multilevel cervical spondylotic myelopathy. [Key Words: cervical spine, decompression, laminoplasty, myelopathy, spondylosis]