Clinical and Radiological Outcomes in C2 Recapping Laminoplasty for the Pathologies in the Upper Cervical Spine

Abstract

Objective: To evaluate C2 muscle preservation effect and the radiological and clinical outcomes after C2 recapping laminoplasty.

Methods: Fourteen consecutive patients who underwent C2 recapping laminoplasty around C1-2 level were enrolled. To evaluate muscle preservation effect, the authors conducted a morphological measurement of extensor muscles between the operated and nonoperated side. Two surgeons measured the cross-sectional area (CSA) of obliquus capitis inferior (OCI) and semispinalis cervicis (SSC) muscle before and after surgery to determine atrophy rates (ARs). Additionally, we examined range of motion (ROM), sagittal vertical axis (SVA), neck visual analogue scale (VAS), Neck Disability Index (NDI), and Japanese Orthopaedic Association (JOA) score to assess potential changes in alignment and consequent clinical outcomes following posterior cervical surgery.

Results: We measured the CSA of OCI and SSC before surgery, and at 6 and 12 months postoperatively. Based on these measurements, the AR of the nonoperated SSC was 0.1% ± 8.5%, the AR of the operated OCI was 2.0% ± 7.2%, and the AR of the nonoperated OCI was -0.7% ± 5.1% at the 12 months after surgery. However, the AR of the operated side's SSC was 11.2% ± 12.5%, which is a relatively higher value than other measurements. Despite the atrophic change of SSC on the operated side, there were no prominent changes observed in SVA, C0-2 ROM, and C2-7 ROM between preoperative and 12 months postoperative measurements, which were 11.8 ± 10.9 mm, 16.3° ± 5.9°, and 48.7° ± 7.7° preoperatively, and 14.1 ± 11.6 mm, 16.1° ± 7.2°, and 44.0° ± 10.3° at 12 months postoperative, respectively. Improvement was also noted in VAS, NDI, and JOA scores after surgery with JOA recovery rate of 77.3% ± 29.6%.

Conclusion: C2 recapping laminoplasty could be a useful tool for addressing pathologies around the upper cervical spine, potentially mitigating muscle atrophy and reducing postoperative neck pain, while maintaining sagittal alignment and ROM.

Keywords: Cervical vertebrae; Laminectomy; Laminoplasty; Muscular atrophy; Postoperative complications; Spinal cord neoplasms.

Fig. 1.

Schematic representation of the C2 muscle preservation procedure. (A) The rectus capitis posterior major (RCPM), obliquus capitis inferior (OCI), and semispinalis cervicis (SSC) muscles are attached to C2 spinous process. The rectus capitis posterior minor is attached to C1 posterior arch. The OCI is the only suboccipital muscle that does not have an attachment to the cranium. (B) Division of the plane between the OCI muscle and the SSC muscles. (C) C2 spinous process is split longitudinally, and lateral gutter are made between the SSC muscles and the OCI muscles. Dotted line indicates the resection margin in the midline spinous process and lateral gutter. The bilateral SSC muscles and OCI muscles were completely preserved. (D) Unilateral C2 spinous process and lamina was retracted to expose spinal canal. While the C2 attachments of the SSC, OCI, and RCPM muscles are left intact, the C2 laminal flaps are elevated to swing open. Either C1 laminectomy or C1 laminoplasty could be possible to expand the surgical exposure. (E) Main surgical procedure and tumor removal can be performed after the opening of C2 lamina. (F) Reconstructing the C2 spinous process/lamina and the muscle attachments. Expanded half of the C2 spinous process then reattached to counterpart with stitch passed through drill-hole in each split half of spinous process.

Fig. 2.

Intraoperative photographs of C2 muscle preservation procedure. (A) C2 spinous process is split longitudinally with a surgical threaded wire (white arrows), leaving all muscular attachments (RCPM, OCI, and SSC muscles). (B) Dividing the plane between the OCI muscle (black arrow) and the SSC muscles (white arrow). A scalpel and bipolar forceps are used in the sharp dissection process to avoid heat damage to the muscles. (C) Making lateral gutter on the C2 lamina using bone scalpel for muscle-preserving C2 laminoplasty. (D) Unilateral C2 spinous process and lamina is retracted to expose spinal canal. While the attachments of the SSC, OCI, and RCPM muscles (at C2) are left intact, the C2 laminal flaps are elevated to swing open. (E) Spinal cord is exposed. Main surgical procedure and tumor removal can be performed after the opening of C2 lamina. (F) Reconstructing the C2 spinous process/lamina and the muscle attachments. Expanded half of the C2 spinous process then reattached to counterpart with stitch (white arrows) passed through drill-hole in each split half of spinous process. The bilateral SSC muscles and OCI muscles are completely preserved. RCPM, rectus capitis posterior major; OCI, obliquus capitis inferior; SSC, semispinalis cervicis.

Fig. 3.

(A) The postoperative axial computed tomography (CT) image demonstrating the measurement of cross-sectional area (CSA) for the OCI muscle at the middle of the C2 spinous process. (B) The postoperative axial CT image demonstrating the measurement of CSA for the SSC muscle at the C23 intervertebral disc level. (C) The postoperative axial CT image demonstrating atrophic change of the OCI muscle (white arrows) after C2 laminectomy for tumor removal. (D) The postoperative axial CT image demonstrating the bilateral atrophy of the SSC muscle at the C23 intervertebral disc level (black arrows) after C2 laminectomy. OCI, obliquus capitis inferior; SSC, semispinalis cervicis.

Fig. 4.

Case 1. (A) Preoperative axial magnetic resonance image are showing that homogenously enhanced intradural mass compressed spinal cord at the C2 level. (B) Postoperative magnetic resonance imaging is showing that there is no enhanced mass or cord compression after the surgery. (C–E) Axial computed tomography images show the change of C2 spinous process and attached muscles before, 3 months after, and 1 year after surgery.

Fig. 5.

(A) Preoperative enhanced magnetic resonance image showing that homogenously enhanced ventral intradural mass compressed spinal cord at the C1–2 level. The axial computed tomography images demonstrating C2 spinous process and the bilateral OCI muscles (CSA) at the C2 level before (B) and after surgery (C). The lateral radiographs demonstrating cervical alignment before (D) and after surgery (E). OCI, obliquus capitis inferior; CSA, cross-sectional area.