New techniques for exposure of posterior cervical spine through intermuscular planes and their surgical application.

STUDY DESIGN: Retrospective study of new muscle-preserving exposure techniques and their application to posterior cervical spine surgery.

OBJECTIVE: To describe muscle-preserving techniques for exposure of the posterior cervical spine, and to demonstrate how their application to a variety of posterior cervical spine surgeries for varying pathologies allows preservation of cervical mobility and stability.

SUMMARY OF BACKGROUND DATA: Although surgical approaches through intermuscular planes have been applied to the extremities and anterior spinal column, to our knowledge, they have yet to be applied to the posterior cervical spine.

METHODS: We have used our new exposure techniques since 2000, applying them to selective mono laminoplasty (73 patients) for cervical myelopathy, muscle-preserving intervertebral foraminotomy (30 patients) for radiculopathy, posterior atlantoaxial instrumentation with muscle preservation (6 patients) for upper cervical instability, and muscle-reserving unilateral posterior arch recapping technique (11 patients) for cervical spinal cord tumors. A total of 120 patients were enrolled in this study. To evaluate surgical outcomes, we reviewed all their clinical records and pre- and postoperative images.

RESULTS: In selective mono laminoplasty, recovery rate according to Japanese Orthopaedic Association (JOA) scores averaged 60.7%. In muscle-preserving intervertebral foraminotomy, the averaged visual analogue scale for radicular pain decreased from 2.53 preoperatively to 0.47 postoperatively. Of 120 patients, 119 showed neither loss of curvature nor neck motion according to a comparison of pre- and postoperative plain x-rays, with only 1 patient who underwent unilateral posterior arch recapping technique for intramedullary ependymoma showing both. No trace of damage to the deep muscles was observed in any of the 17 patients who underwent posterior atlantoaxial instrumentation with muscle preservation or unilateral posterior arch recapping technique on postoperative magnetic resonance imaging.

CONCLUSION: The muscle-preserving exposure techniques described here can be applied to a variety of posterior cervical spine surgeries for varying pathologies, with no adverse effect on cervical mobility or stability.