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

Abstract

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.