The Surgical Choice And Outcome Of Lower Cervical Spine Injury Based On SLIC And AOSpine Subaxial Cervical Spine Injury Classification System

Objective: To evaluate the application of SLIC and AOSpine subaxial cervical spine injury classification system in the surgical choice and operative effect of lower cervical spine injury.Methods: A total of 55 patients with cervical spine injury were enrolled in our department from June 2013 to October2016.All patients met the inclusion criteria,and the case data were complete.All patients were evaluated with SLIC and AOSpine classification system before operation.Based on two classification systems,we developed the surgical strategy for each patient according to damageof disco-ligamentous complex,neurological status,facet joint injury and special cases of patients(such as severe intervertebral disc herniation,stiffness / metabolic bone disease,etc.).Among them,44 cases were treated with anterior cervical operations,11 cases received surgeries with combined anterior and posterior approach.The postoperative neurological function recovery were evaluated by ASIA and JOA.The bone graft fusion was assessedbased on Bridwell method.Results: For type A injury,there were 3 cases of type A1,4 cases of type A2,3 cases of type A3,and 7 cases of type A4.Three cases had 5 points in SLIC score,9 cases had 6 points,and 5 cases had 7 points,respectively.Patients had vertebral compression or burst fracture and anterior ligament damage mainly,with no obvious damage in the facet joints and posterior ligaments were treated with anterior operation.For type B injury,nine cases had Type B2 injury.Eight cases had 7 points in SLIC score,and 1 case had 9 points.All cases had cervical spine subluxation with no vertebral body fracture.The damage of disco-ligament complex was mild.Since anatomical reduction was achievedafter preoperative traction,all patients were treated with anterior operation. There were 9 cases of type B3.In SLIC score,2 cases had 7 points,4 cases had 8 points,and 3 cases had 9 points.The ligament and structure of anterior column were severely damaged in 6 cases,which were treated with anterior operation.Two cases withcervical fracture-dislocation combined with ankylosing spondylitis,and 1 case with intervertebral disc herniationand pedicle and laminar fracture were treated with combined anterior and posterior operation.There were 20 cases had Type C injury.Seven cases had 9 points in SLIC score,13 cases had 10 points.Anatomical reduction was achieved after preoperative skull traction or intraoperative instrumentation,11 cases of lower cervical locked-facet dislocationwith milddisco-ligament complex injuryreceived anterior surgery with fixation.While a single approach to restore the cervical stability was not expected,7 cases of lower cervical locked-facet dislocation with severedisco-ligament complex injury were treated with combined anterior and posterior approach.One case of lower cervical locked-facet dislocation with severe disco-ligament complex injury was treated with anterior operation in the local hospital.However,the internal fixation fell off after the operation,and asecond operation of combined anterior and posterior approach was performed in our hospital.1 case of cervical burst fracture and dislocation with left facet fracture and severe disco-ligament complex injury was treated with anterior surgery,and after the operation the internal fixation also fell off.According to the surgical strategy recommended by SLIC and AOSpine classification system,2 cases of type C injuryshould had combined anterior and posterior surgeries.However,they only had anterior surgery and their internal fixation fell off later.The surgical methods forother patients were consistent withthe recommendation of two classification systems.All patients underwent regular follow-up.The time of follow-up was from 3 months to 3.58 years.The average time of follow-up was 2.01 years.Pain,numbness and other symptoms of all patients were relieved in the last follow-up.X-ray,CT with three-dimensional reconstruction or MRI scanin the last follow-up verified the proper position of the screws,and bone fusion was achieved in all patients.Two cases had internal fixation failure,while no internal fixation rupture,loose,sinking,prolapse and other complications were found inother patients.The ASIAgrade of48 patients increased 1.21 grades after surgery which was higher than preoperative ASIA grade(P<0.05),while 6 cases with preoperative ASIA grade A and 1case with internal fixation failure(give up treatment after the first operation)did not have significant improvement in neurological function.The postoperative JOA score in all patients was significantly improved compared with preoperative JOA score(P<0.05).The overall bone graft fusion is satisfactory with43 Cases in grade I Bridwell bone graft fusion classification,11 cases in grade II,while 1 case lost follow-up and the bone fusion could not be assessed.Conclusion: 1?SLIC score contribute to determine whether the surgery isneeded,while AOSpine classification isbetterfor the assessment of the detailed structure damage of lower cervical injury.2?The surgical approach and operation strategy based on the combination of SLIC and AOSpine classification system,and the damage of disco-ligamentous complex,neurological status,facet joint injury and spinal cord compression will reduce the risk of internal fixation failure,promote the recovery of neurologicalfunction.3?Patients with type A1-4,type B2 and type B3 injuries and SLIC score between 5 point and 8 point are mostly suitable for anterior surgeryto restore cervical stability.Patients with type C injury and SLIC score between 9 point and 10 point with mild disco-ligament complex damage and intactfacet joint can be treated with anterior surgery to restore cervical stability.Patients with type C injury with severe disco-ligament complex and facet joint damage can be treated with combined anterior and posterior operation.