[The causes and prevention of C₅ nerve root palsy after anterior cervical decompression and fusion].

To analyze the causes of muscular paralysis due to C₅ nerve root injury after anterior cervical decompression and fusion (ACDF) and explore its prevention way.From January 2005 to December 2015, 310 patients underwent ACDF in our hospital. Of them, 9 cases occurred muscular paralysis due to C₅ nerve root injury after operation. The clinical data of 9 patients were retrospectively analyzed. There were 8 males and 1 female, aged from 51 to 84 years with an average of 64 years. Two cases underwent internal fixation and intervertebral fusion with one segment, 6 cases with two segments, 1 case with three segments. Simple deltoid muscle weakness, pain, numbness happened in 7 cases, simultaneously biceps brachii muscle weakness, pain, numbness in 2 cases. Muscle strength was 0 grade in 1 case, 1 grade in 3 cases, 2 grades in 4 cases, 3 grades in 1 case.The follow up time of 9 patients was more than 12 months and the longest was 24 months with an average of 14 months. Muscle strength of 7 patients recovered to 4-5 grades. Recovering time after operation was directly proportional to the degree of injury, those patients with muscle strength level more than 2, usually could have significant improvement within 3 weeks. The JOA score improved from 10.89±1.89 preoperatively to 8.92±1.91 postoperative C₅ nerve root palsy to 14.48±2.10 at final follow up, with significant difference(P<0.05).More complicated factors result in C₅ nerve root injury after ACDF. Except those suffered severe grinding contusion and amputation, most of the patients can get satisfactory prognosis. Strict control of the operation indication, selection of the right surgical segment with accurate manipulation, control of the distraction of intervertebral space and the width of the multilevel anterior cervical corpectomy, are main methods to prevent the complication.