Posterior Expansive Open-door Laminoplasty And Pedicle Screw Fixation For Spinal Cord Injury Without Radiological Abnormality In Stenotic Cervical Spine

Abstract:objective:To investigate the clinical efficacy of posterior expansive open-door laminoplasty and pedicle screw fixation for spinal cord injury without fracture or dislocation in patients with cervical stenosis. Methods:Between June2006and March2011,44patients （28males and16females.） with cervical spinal cord injury with cervical stenosis but without fracture or dislocation in plain films were included to receive posterior C3to C7expansive open-door laminoplasty and pedicle screw fixation. Inclusion criteria:1.patients with cervical stenosis suffered from spinal cord injury without fracture and dislocation of the cervical spine.2. Absence of local anterior compression in radiographs.3. Multi-level anterior compressions, especially patients presented with due to multiple anterior and posterior compressions.4. Absence of vertebral artery deformity or encasement according to CT angiography.5. Absence of congenital cervical deformity or previous operations on cervical spine. Exclusion criteria:1. non-stenotic cervical spine injury.2. Spinal cord injury secondary to disc herniation.3. Single level of two-level compression by osteophyte or ossification of posterior longitudinal ligaments.4. unclear of posterior inferior part of C7vertebrae in radiographs.5. Tuberculosis, tumor or other infectious disease of cervical spine.6. Previous operation on cervical spine. The mean age was51.7±8.2years （range,34-71years）. The mechanism of injury included11motorcycle accidents,7falls from a stand-height,9falls from a height,9bicycle accidents,2crush injuries,2injuries from cervical massage and4diving injuries. All patients developed incomplete spinal cord injury, including central cord syndrome in26patients, anterior spinal cord syndrome in12, Brown-Sequard syndrome in4and mixed type in2. The mean preoperative JOA score was7.2±2.3（range,4to13）. Neurological functions were assessed in terms of improvement rate of JOA score. The cervical alignment, position of implants and status of the canal were evaluated by roentgenograms and computed tomography （CT）.Results:All patients were successfully managed with this technique. Operation time was mean of130±15.5min （range,100to180min） and blood loss was mean of250±48.5ml （range,150to600ml）. All patients have no other major complications occurred. Totally,180screws in44patients were implanted, including52in C3,68in C4,36in C5,18in C6,2in C7. the instrumented segments included4cases of two-segement fixation,2in C3-5,1in C3-4、C5-6,1in C4₆. Intraoperativ,8patients developed ecessive bleeding（non-pulsatile） from the screw tract, which subsided after screw insertion. Postoperativ CT demonstrated lateral cortical perforation in8cases and no spinal canal intrusion occured. The40patients were followed up for an average of25.2±17.8months （range,12to60months）. But for5patients who still sustained a poor functional improvement of upper extremities, the JOA improvement rate was68.5%at last follow-up. Two of them needed reoperations to decompress the residual anterior compression by anterior cervical decompression and fusion procedure. After that, satisfactory improvement of neurological function was documented. Postoperative radiography demonstrated that cervical alignment was maintained in all patients and no implant failure and spinal instability developed. CT scan showed screws were in place and the patency of spinal canal was maintained. No reclose of the canal and fracture of hinge occurred during follow-up. Conclusions:Posterior cervical laminoplasty combined with pedicle screw fixation is an effective procedure for patients with cervical stenosis after cervical spinal cord injury without fracture and dislocation. This procedure is highly practicable and useful in terms of stabilizing the instable segments, restoring cervical alignment, reducing postoperative axial symptoms and maintaining the position of the laminoplasty and thus promoting recovery of neurological functions.