Mid-term Follow-up Study Of Odontoid Process Reduction In Patients With Basilar Invagination

ObjectiveTo evaluate the mid-term effect of halo-traction combined with intraoperative reduction of odontoid process and posterior occipitocervical instrumentedfusion in the treatment of basilar invagination.MethodsRetrospective analyze 53 patients with with basilar invagination treated in The First Affiliated Hospital of Zhengzhou University from January 2009 to December 2014.All patients were treated with progressive traction reduction by halo-traction for 2-4 weeks before surgery,and the odontoid process was further reduced with continuous traction and posterior occipitocervical instrumented fusion during surgery.Radiographic analysis evaluated changes in atlantodental distance,McGregor's line violation,spinalcanal width at the craniovertebral junction,cervicomedullary angle,C2-C7 lordosisangle,and the occiput-C2 angle.Clinical outcomes were evaluated according to visual analogue scale(VAS)and Japanese Orthopedic Association(JOA)scoring system.Incidence of complications after operation was also recorded and analyzed.ResultsAmong the 53 patients,23 were male and 30 were female,with an average age of 41.34 years old.The follow-up time was 48-112 months,with an average of 62.53 ±13.74 months.The average operative time was 173.67 min.The average intraoperative blood loss was 163.28 ml.Satisfied reduction of odontoid process were identified in all these patients.The odontoid process can be reduced in the horizontal and sagittal plane by 50%.Combined intraoperative reduction and posterior occipitocervical instrumented fusion to stabilize the odontoid process,the rates of complete anatomical reduction were 84% for atlantoaxial distance,and 95% for basilar invagination.The score of pain before traction was 7.45 points(range,5-9),after traction was 7.61 points(range,6-9),the JOA score before traction was 9.24 points(range,4-11),and after traction was 9.43 points(range,5-11).There was no statistical difference in the score of pain and JOA before and after traction.Most of the patients reported satisfactory pain relief and improvement in daily activity after the surgery.Postoperative pain score was 0.63(range,0-3)and JOA score was 15.56(range,11-17),both significantly improved compared with that before traction(P<0.05).Complications occurred in 12 patients,all of which healed uneventfully after symptomatic treatment.The bony fusion rate was 100%.ConclusionPreoperative halo-vest traction combined with intraoperative instrumental reduction of odontoid process and posterior occipitocervical instrumentedfusion is a safe and effective method for the treatment of complex craniocervical junction deformity.