Clinical Research On The Accuracy Of Cervical Pedicle Screw (Attached With Analysis Of Clinical Effect On 510 Screws Of 105 Patients)

Objective:To evaluate the clinical effect of a self-developed technique of manual placement of pedicle screw in cervical spine based on anatomical research.Methods:Data of 105 patients who had cervical pedicle screw placement within seven years(from April 2007 to April 2013,and April 2013 to April 2016)were retrospectively analyzed,including 60 male and 45 female,aged from 20 to 76 years(51.7±14.5 years).Five main types of spinal injury were included: traumatic spinal injury(61 cases),degenerative cervical injury(19 cases including 12 ossification of posterior longitudinal ligament and 17 cervical spondylosis),cervical cancer(16 cases including 9 schwannoma,4 meningioma,and 3 cases of cervical vertebral tumor),deformity(6 cases including 3 kyphosis and 3 ngenital malformation),and intervertebral space infection(3 cases).All the patients were received X-ray,CT scan and MRI imaging pre-operation,and were taken X-ray and CT scan post operation to assess the accurate of the position of screws.The accuracy of pedicle screws placement and screw leaning degree were analyzed according to the Lee standard.Grade 0: no penetration;Grade I: pedicle penetration within 25% of the pedical screw diameter;Grade II: pedicle penetration between 25% to 50% of the pedical screw diameter;Grade III: pedicle penetration beyond 50% of the pedical screw diameter.Grade II and III are considered as misplacement.And all patients with Grade II and/or III were observed complications of blood vessels and nerve injury,etc.ASIA was used to classify spinal injury among patients with traumatic,while JOA was used to evaluate neural function improvement within patients with non traumatic.Results:A total of 510 screws were placed by manual placement into the 105 patients.Among 99 patents(6 without post-operative CT scan were excluded)with 497 screws(including 201 in upper cervical spine,and 296 in lower cervical spine)were grading as following:(1)Screw placement accuracy: 486 screws in Grade 0,8 screws in Grade I,3 screws in II grade,and 0 screws in III Grade.(2)11 screws were penetrated pedical cortex with 8 in Grade I and 3 in Grade II(2 penetrated into cortical paries medialis and 1 penetrated into paries lateralis,but no screw penetrated into upper or inferior border).The accuracy of screw placement is 97.79%(Grade 0),the total misplacement rade was 0.6%(Grade II and III).According to post-operative follow up in 12 to 30 months(average 20.6±5.2 months),no complication of spinal,nerve root,or vascular injury was found,no screw loosening or fracture,all bones were healing properly.Follow up in the 6 months after operation showed patients with traumatic had significantly improvement,while patients with non traumatic had been improved according to JOA(p<0.05).Conclusion:Based on the study,the technique of manual placement of pedicle screw in cervical spine is considered as with high safety and reliability,which has wide indication,and worthy of clinical application and popularization.