Comparison of incidence of C5 nerve palsy after laminoplasty and laminectomy with internal fixation / 中华骨科杂志

ABSTRACT

ObjectiveTo compare the incidence of C5 nerve palsy after laminoplasty and laminectomy with internal fixation for treating multilevel cervical spondylotic myelopathy (MCSM).MethodsFrom January 2005 to June 2010,68 patients with MCSM were treated with laminoplasty (27 patients,group A) or laminectomy with internal fixation(41 patients,group B).There were 21 males and 6 females in group A,aged 33-80 years(average,60.4 years),31 males and 10 females in group B,aged 22-77 years (average,58.7 years).All the patients were followed up for 12-48 months (average,22 months).In both groups,Cobb's method was applied to measure cervical lordotic angle,and Ishihara's method was conducted to measure cervical curvature index(CCI) before and after operation.The incidence of C5 nerve palsy was recorded and compared.Then we further compared preoperative and postoperative the cervical lordosis angle and CCI of 9 patients with C5 nerve palsy (group B1) and 32 patients without C5 nerve palsy (group B2) in group B.ResultsThe incidence of C5 nerve palsy in group A was 3.7％(1/27),while 22.0％(9/41) in group B (x2=4.32,P＜0.05).For all ten patients with C5 nerve palsy,the muscle strengths of paralyzed muscles were recovered to grade 4 or better after being treated with conservative treatment for an average of 14 months.The change rate of preoperative and postoperative CCI in group B1 was 38.07％±18.03％,while 22.81％±12.71％ in group B2.There was a statistical difference between group B1 and group B2 (t=2.88,P＜0.05).Conclusion Compared with laminoplasty,laminectomy with internal fixation has a higher incidence of C5 nerve palsy.The C5 nerve palsy may be associated with postoperative increase of cervical lordosis angle.Moreover,tethering of the C5 root may be one of its important pathomechanisms.