[Outcomes and related factors of C₅ nerve root palsy after cervical posterior single open-door laminoplasty].

Objective: To analyze the clinical outcomes and related factors of C₅ palsy following cervical laminectomy in treating multi-segments cervical spondylotic myelopathy.

Methods: From January 2010 to June 2014, 80 patients with spondylotic myelopathy underwent C₃-C₆ open-door laminoplasty(group A) and 80 patients C₄-C₆ open-door laminoplasty (group B). The mean age was (68.4±9.2) years (44 males and 36 females) in group A and the mean age was (66.8±8.9) years (48 males and 32 females) in group B. Japanese Orthopaedic Association(JOA) score, Visual Analogue Score, incidence of C₅ palsy, time of onset, grade of muscle weakness, other accompanying cervical nerve root palsies, recovery time were used to evaluate clinical effects before operation and at last follow-up. Radiographically, changes of Cobb angle of sagittal plane from C₂-C₇, cervical range of motion, minimal spinal cord diameter on MRI were analyzed before operation and at last follow-up.

Results: All the patients were followed up from 6 to 15 months with an average of (12.4±3.2) months. No obvious differences were observed between change of VAS of cervical and upper limb, JOA, Cobb angle, cervical range of motion, minimal spinal cord diameter on MRI. C₅ nerve root palsy occurred in 7 cases (8.75%) in group A, including 4 cases of upper limb pain, 3 cases of upper limb pain, and 2 cases of residual upper limb pain and sensory loss at the last follow-up. C₅ nerve root palsy occurred in 5 cases (7.5%) in group B, 3 cases of upper limb pain, 2 cases of upper limb sensory loss, and all patients recovered normal radiation pain and sensory loss at the last follow-up. There was no significant difference in the incidence of C₅ nerve root palsy between the two groups. C₅ nerve root palsy, deltoid muscle, accompanied by neurological symptoms, recovery time were(2.3±1.0) N, 30 cases (37.5%), (11.4±1.0) weeks in group A, (2.8±0.8) N, 23 cases (28.8%), (8.2±0.8) weeks in group B, there was no significant difference on deltoid muscle decreased between the two groups, accompanied by neurological symptoms and the recovery time in group A was worse than the group B.

Conclusions: Comparison of the two kinds of operation, the probability of postoperative C₅ nerve root palsy was equal, but the C₅ nerve root palsy in patients with C₄-C₆ open-door laminoplasty showed lighter symptom and faster recovery.