A new mri dorsal spinal cord migration pattern may reduce C5 palsy in C3 dome C7 reverse dome open door laminoplasty.

INTRODUCTION

The C3-dome, C7 reverse dome open-door laminoplasty technique preserves posterior cervical musculature and has been reported to improve postoperative cervical alignment while reducing axial neck pain and C5 palsy. This study investigates differences in postoperative dorsal cervical cord migration with this new technique compared to published data on traditional laminoplasty.

METHODS

A retrospective review was performed on consecutive patients who underwent C3 dome-C7 reverse dome open-door laminoplasty for cervical myelopathy. Clinical, surgical, and radiological outcomes were analyzed, with emphasis on postoperative MRI cord migration and C5 palsy.

RESULTS

Eighty-one patients (50 males, 31 females) with at least two years' follow-up were included. Mean intraoperative blood loss was 233 ± 216 ml. The mean mJOA score improved from 12.9 ± 2.8 to 15.1 ± 1.4, with an average gain of 2.2 ± 2.0. Two patients developed superficial wound infections, managed successfully with oral antibiotics. No C5 palsy, implant failure, or revision surgery occurred. C2-7 sagittal alignment (p=0.911) and cervical range of motion (p=0.869) were unchanged postoperatively. Mean dorsal cord migration by level was: C3: 0.60 ± 0.8 mm, C3/4: 0.86 ± 1.0 mm, C4: 1.38 ± 0.9 mm, C4/5: 1.7 ± 1.0 mm, C5: 1.81 ± 1.0 mm, C5/6: 1.8 ± 1.1 mm, C6: 1.9 ± 0.9 mm, C6/7: 1.32 ± 1.0 mm, C7: 0.1 ± 1.4 mm. Compared with traditional laminoplasty, two key differences were noted: (1) the maximal cord migration apex shifted caudally to C6 (versus C5), and (2) overall dorsal migration was more controlled and reduced.

CONCLUSION

This study is the first to define cord migration patterns after C3 dome-C7 reverse dome open-door laminoplasty. The caudal shift of maximal migration to C6 and reduced overall dorsal displacement likely reduces C5 root traction, potentially lowering the risk of postoperative C5 palsy.

LEVEL OF EVIDENCE: IV.