Preservation of the spinous process-ligament-muscle complex to prevent kyphotic deformity following laminoplasty.

BACKGROUND CONTEXT: Long-term results of patients treated with conventional laminoplasty have shown a significant number of patients complicated with kyphotic deformity. The authors hypothesize that by maintaining the spinous process-ligament-muscle complex (SPLMC) during laminoplasty, followed by postoperative muscle strengthening exercises, the formation of kyphosis can be decreased. PURPOSE: To evaluate the incidence of kyphosis in a select patient group undergoing laminoplasty with preservation of the SPLMC followed by neck strengthening exercises. STUDY DESIGN/SETTING: A midterm retrospective study of 30 patients following laminoplasty with preservation of the SPLMC. PATIENT SAMPLE: Thirty consecutive patients with cervical myelopathy attributable to multilevel cervical spinal stenosis underwent laminoplasty with preservation of the SPLMC from April 1998 to July 2002. OUTCOME MEASURES: Preoperative and postoperative Japanese Orthopedic Association (JOA) scores, Guigui angles, and axial symptoms were measured. METHODS: Thirty patients with multiple-level cervical myelopathy were studied. Fourteen had a normal lordotic curve, whereas 16 had a straight curve. All these patients underwent laminoplasty with preservation of the SPLMC. For the first 6 months, isometric neck muscle exercises were performed. After this time, the intensity of the exercises was gradually increased. RESULTS: The average preoperative JOA score was 5.8+/-1.4. Mean JOA score at 3.8 years follow-up was 13.6+/-2.1. The recovery ratio was 69%. All 14 presurgical lordotic curves remained lordotic. Fourteen of the 16 straight spines improved to a lordotic configuration. Using the Guigui method, the preoperative lordotic angle was corrected by approximately 9 degrees (mean preoperative of 9.89+/-1.13 degrees, mean postoperative of 18.66+/-1.85 degrees), and the preoperative straight angle was corrected by approximately 15 degrees (mean preoperative of 0.91+/-2.14 degrees, mean postoperative of 15.88+/-1.71 degrees). CONCLUSIONS: Laminoplasty with preservation of the SPLMC followed by appropriate postoperative muscle exercises may be an encouraging way to maintain or restore the physiological curve and prevent kyphotic deformity at a medium term follow-up.