Preservation of Deep Cervical Extensor Muscle Volume: Comparison Between Conventional Open-Door and Muscle Preserving Laminoplasty Approaches in the Same Patients

Abstract

Surgical laminoplasty techniques have been developed to reduce cervical kyphosis and postoperative axial neck pain and preserve the posterior cervical extensor muscles. We compared a unilateral conventional open approach (OA) and a contralateral muscle preserving approach (MPA) for laminoplasty in the same patients to determine differences in the preservation of the posterior cervical muscles after the 2 approaches. This study was a prospective observational study involving 44 patients who underwent laminoplasty with unilateral OA and contralateral MPA for cervical myelopathy from January 2005 to December 2013. The cross-sectional area (CSA) changes in the posterior cervical extensor muscles (multifidus, semispinalis cervicis, and semispinalis capitis muscles) were measured on computed tomography scan, both pre- and postoperatively. Using an OA, the multifidus and semispinalis cervicis muscle preservation was 58.2% and 67.0%, but using an MPA, muscle preservation was 97% and 90.8% (P < 0.001 and P= 0.042), respectively. However, the CSA of the semispinalis capitis muscle did not differ significantly between the 2 groups. In terms of the level, conservation of the multifidus muscle was significantly different according to the approach at all levels, and the conservation of the deep extensor muscles was significantly different at the C3-4 level. MPA was effective in preserving the volume of deep cervical extensor muscles and helping minimize postoperative musculoskeletal complications. In addition, muscle preservation was more effective at the C3-4 level.