Expansive Midline T-Saw Laminoplasty (Modified Spinous Process-Splitting) for the Management of Cervical Myelopathy

Abstract

The authors developed a method of spinous process-splitting laminoplasty using a threadwire saw in a prospective study of 25 patients with cervical myelopathy. This report describes the surgical technique and the results of the expansive midline laminoplasty performed with an threadwire saw. To compare the efficacy of midline, threadwire-saw laminoplasty with that of the original spinous process-splitting laminoplasty. The spinous process-splitting laminoplasty was described by Kurokawa in 1982. Although the procedure has a number of theoretical and practical advantages, it has not been widely used because of technical difficulties. Twenty-five patients who underwent expansive, midline, threadwire-saw laminoplasty from C3 to C7 for cervical myelopathy were studied. The threadwire saw was used to split the spinous processes. The mean follow-up period was 34 months. Neurologic results were evaluated with pre- and postoperative scores, and recovery rates were evaluated by methods described in previous reports using the Japanese Orthopaedic Association scoring system. Radiographic data analyzed included plain radiographs and computed tomography scans. The duration of surgery and the amount of blood lost during this procedure using the threadwire saw were compared with the duration and blood loss that occurred during the original Kurokawa's procedure using a burr. In all cases, good enlargement of the cervical canal was achieved. The mean increase in cervical cross-sectional area was 36.1%, according to computed tomography scans. No dural tears occurred, and no patients experienced any decrease in neurologic function. The neurologic recovery rate was 72%, which was almost same as the neurologic recovery rate in the original procedure. Using the threadwire saw, the mean duration of surgery was 63 minutes shorter and the mean blood loss was 70 cc less than in procedures using burrs. The application of the threadwire saw to split the spinous processes made Kurokawa's procedure simpler, faster, and safer.