Preliminary report of C1-C2 pedicle screw fixation for pediatric atlantoaxial dislocation

English Keywords:Atlantoaxial dislocation  Pediatrics  Atlas  Pedicle screw  Internal fixation

English Abstract:

  【Abstract】 Objectives: To investigate the surgical feasibility and short-term clinical outcome of C1-C2 pedicle screw fixation for pediatric atlantoaxial dislocation. Methods: Between September 2005 and March 2011, 16 cases suffering from pediatric atlantoaxial dislocation undergoing atlantoaxial pedicle screw instrumentation were reviewed retrospectively. There were 9 males and 7 females with the age at time of surgery ranging from 5 to 13 years(mean, 9.1 years). All patients presented with pain at craniocervical junction and neck stiffness. 3 cases were complicated with medulla compression, and according to ASIA classification, there were 2 grade D and 1 grade C. Standard anterior-posterior, lateral and flexion-extension radiographs, computed tomography and MRI of cervical spine were obtained in all patients before operation. All patients presented with atlantoaxial dislocation, and the pathogenesis included disruption of transverse ligament(n=1), atlantoaxial fracture and dislocation(n=1), congenital odontoid malfromation(n=12), atlantoaxial rotatory subluxation(n=2). Cervical spinal cord compression was identified in 5 cases. The height of C1 posterior arch was 2.5-3.8mm(average, 3.0mm). The atlanto-dental interval(ADI) was 6-14mm(average, 9mm). Preoperative skull traction was performed rou-tinely on all cases for 1-2 weeks, and complete reduction was achieved in 7 cases, incomplete reduction in 5 cases, and no reduction in 4 cases. All patients had C1 pedicle screws placed as part of a fixation construct with pedicle exposure method(PEM). C1-C2 pedicle screw placement under direct vision intraoperativeiy, reduction and fixation, bone graft and fusion were administered in all cases. The neurological function and CT scan were used to evaluate the surgical outcome. Results: All 16 patients underwent bilateral atlantoaxial pedicle screw fixation. All operations were completed successfully. A total of 64 screws were successfully placed. Reduction and fixation were successfully performed. No intraoperative or postoperative complication(neurological or vascular injury) was noted. Overall, mean estimated blood loss(EBL) was 300ml(range, 150-650ml), operative time averaged at 130(range, 100-190) minutes. Of the 16 cases, 12 cases were followed up from 12 to 72 months(on an average of 28.5 months). All 12 patients had clinical symptoms improved, even 3 cases with neurological deficit including 2 from grade D to grade E and 1 from grade C to grade D. All 12 cases showed evidence of solid fusion 3 to 6 months after operation. No instrument failure was noted in any case. Conclusions: Technique of atlas pedicle screw with PEM is generally feasible and safe. C1-C2 pedicle screw fixation has been proven to be an effective treatment with satisfactory short-term result for pediatric atlantoaxial dislocation.