Clinical Outcomes Of ACDF In Single-segment Cervical Spondylotic Myelopathy With Developmental Cervical Spinal Canal Stenosis

Objective:To evaluate of clinical outcomes of the treatment of single-segment cervical spondylotic myelopathy with developmental cervical spinal canal stenosis by anterior cervical discectomy and fusion.Methods:This article retrospectively analyzed 66 patients with single-segment cervical spondylotic myelopathy from June 2015 to June 2017 who were treated by ACDF in our hospital.The patients were divided into DCS group(30 cases)and NDCS group(36 cases)according to the presence of sagittal diameter of spinal canal/vertebral body<0.75 in consecutive 3 levels on lateral cervical radiographs.There were 21 males and 9 females in DCS group(aged 48.43±10.06 years),and 23 males and 13 females in NDCS group(aged 48.83±7.34 years).There was no significant difference in gender and age between the two groups(P>0.05).The follow-up period was 39.03±2.14 months in DCS group,and 39.17±1.93 months in NDCS group,which was no statistically significant difference between the two groups(P>0.05).Perioperative complications were recorded in both groups.Neck Disability Index(NDI)score,Japanese Orthopaedic Association(JOA)score and X-ray were compared between the two groups before surgery,3months postoperatively,1 year postoperatively,and at final follow-up.At the same time,cervical curvature(C2～C7 Cobb angle)and the height of intervertebral space at the fusion segment were measured on lateral cervical radiographs.The fusion rate was recorded and evaluated.The excellent rates of JOA improvement were compared between the two groups at final follow-up.Results:All the patients completed the surgery successfully.3 patients(1 in the DCS group and 2 in the NDCS group)showed dysphagia after the surgery,however,the symptoms disappeared after 1 weeks of symptomatic treatment.There were no statistically significant differences between the DCS group and the NDCS group in operational time(78.23±10.41 min vs 76.72±10.66min)and intraoperative blood loss(32.27±5.07 ml vs 30.50±5.53ml),respectively(P>0.05).The JOA scores before surgery,at 3 months,1year after surgery,and final follow-up were(7.63±1.50),(12.73±1.41),(13.83±1.58),and(15.03±1.73)of DCS group,while those were(8.08±1.86),(12.97±1.70),(13.97±1.59),and(15.06±1.47)of NDCS group,respectively.The NDI scores before surgery,at 3 months,1 year after surgery,and final follow-up were(38.42±5.90)%,(19.89±2.25)%,(13.67±2.99)%,and(4.83±3.66)% of DCS group,and(36.26±6.63)%,(19.96±3.05)%,(14.61±2.75)%,and(5.69±2.76)%of NDCS group,respectively.The JOA score and the NDI score were significantly improved in both groups after surgery(P<0.05),and they were with no significant differences between both groups at the same time point(P>0.05).In the DCS group,the Cobb angle was(11.27±5.56)° before surgery,(14.80±5.53)° at 3 months after surgery,(14.97±5.11)° at 1 year after surgery and(15.64±4.86)° at final follow-up,and the intervertebral height of fusion segment was(5.71±1.47)mm before surgery,(7.56±1.43)mm at 3 months after surgery,(7.07±1.84)mm at 1 year after surgery and(6.93±1.61)mm at final follow-up.In the NDCS group,the Cobb angle was(11.66±5.23)°before surgery,(14.88±5.93)° at 3 months after surgery,(15.12±6.12)° at 1 year after surgery and(15.76±5.29)° at final follow-up,and the intervertebral height of fusion segment was(5.58±1.75)mm before surgery,(7.63±1.54)mm at 3 months after surgery,(7.19±2.09)mm at 1 year after surgery and(7.14±1.74)mm at final follow-up.The Cobb angle and the intervertebral height of fusion segment were significantly improved in both groups after surgery(P<0.05).There was no significant difference between both groups at the same time point(P>0.05).All patients achieved bony fusion at1 year follow-up.At the last follow-up,there was no significant difference in the excellent rates of JOA improvement between the two groups(P>0.05).Conclusion:ACDF the treatment of single-segment CSM with DCS can effectively restore nerve function,reliable stability,rebuild cervical curvature and restore the height of intervertebral space,improve fusion rate and the clinical outcomes is satisfactory.