Clinical Study Of Posterior Extensor Muscles-preserving Laminectomy To Treat Multilevel Cervical Spondylotic Myelopathy

Objectives:Evaluating the clinical effects of the technique for posterior extensor muscle-preserving laminectomy(TEMPL) to treat multilevel cervical spondylotic myelopathy(MCSM).Methods:Twenty patients with MCSM undergone the microscope-assisted TEMPL from the the orthopaedic surgery of the first affiliated hospital of Nanchang University between October 2012 and April 2014 were included(group A) Twenty-four patients with MCSM conducted with open-door laminoplasty(ODLP) have been chosen as controls(group B) in the same duration. A prospective study is designed to compare the Japanese Orthopaedic Association(JOA) Scores, the recovery rate of cervical cord function, visual analogue score(VAS), axial syndrom(AS) and C5 paresis before surgery, after surgery and at the final follow-up between two groups. Preoperative and postoperative cervical curvature indexes were calculated according to Borden’s method. Preoperative and the final follow-up ranges of neck motion(ROM) were measured on lateral flexion and extension radiographs, the retained ROM rate postoperatively was calculated. The intraoperative blood loss and the length of hospital stay were recorded.Result: JOA score in group A increased from 6.80±0.77 preoperative to 10.15±0.89(3 months postoperative), and to 13.70±0.86 at the final follow-up(12 months postoperative), JOA score increased from 7.29±0.86 preoperative to 10.67±1.12(3 months postoperative), and to 14.04±0.86 at the final follow-up(12 months postoperative) in group B, which showed no significant difference between two groups(P>0.05). The recovery rate of cervical cord function at the final follow-up was 67.41±8.77% in group A and 69.53±8.61% in group B, which showed no significant difference between two groups(P>0.05); VAS in group A increased from 1.35±0.59 preoperative to 2.95±0.02 5 days postoperative, but VAS increased from 1.67±0.56 preoperative to 4.92±0.72 5 days postoperative in group B. The value was significant difference 5 days in surgery between two groups(P<0.001); None of the patients complained of persistent AS postoperatively in group A, however, 5 patients suffering persistent AS and need drug treatment in group B. None of the group A existed C5 paralysis,but two patients had the complication in group B. The cervical curvature index, D value, preoperatively and at the final follow-up was 10.15±1.04 mm and 10.55±1.04 mm in group A compared to 10.46±1.25 mm and 9.21±1.20 mm in group B, which showed no significant difference preoperatively(P>0.05) and significant difference at the final follow-up between two groups(P < 0.001). The ROM averaged 54.25±2.60° before surgery and 51.90±2.25° at the final follow-up in group A, 55.46±2.25° before surgery and 44.75±2.49° at the final follow-up in group B, which showed no significant difference preoperatively(P>0.05) and significant difference at the final follow-up between two groups(P<0.001). The surgery retained 95.77±4.55% of cervical ROM in group A, compared to 80.72±3.80% in group B with significant difference(P<0.001); Intraoperative blood loss averaged 83.30±12.41 ml in group A and 349.80±37.29 ml in group B, length of hospital stay averaged 4.35±0.59 days in group A and 7.46±0.55 days in group B, which both showed significant difference between two groups(P<0.001).Conclusions :TEMPL not only contributes more satisfactory clinical effects with less invasion than ODLP to patients with MCSM, also decreases hospital stays, reserves cervical ROM, reduces loss of cervical curvature, lowers postoperative AS and C5 paralysis rate.