The severity of basilar invagination and atlantoaxial dislocation correlates with sagittal joint inclination, coronal joint inclination, and craniocervical tilt: a description of new indexes for the craniovertebral junction.

BACKGROUND: Joint-distraction and intra-operative manipulation surgeries to correct basilar invagination (BI) and atlantoaxial dislocation (AAD) are becoming standard procedures. However, current data are unable to aid in the understanding of normal and abnormal morphology of the C1/C2 joints. OBJECTIVE: To study various aspects of C1/C2 joint morphology to create normative and patient data on joint abnormalities that could provide the surgeon with objective data for surgical planning and approach. METHODS: Seventy patients (age, 15-45 years) were compared with an equal number of age- and sex-matched control subjects (age, 21.9±8.2 years) with irreducible BI and AAD from a developmental origin (May 2010-July 2013). Joint anatomy was studied with the use of thin-slice computed tomography scans. The joint parameters studied included sagittal joint inclination, craniocervical tilt, coronal joint inclination, surface area, joint overlap index, and joint reciprocity. The severity of BI and the severity of AAD were compared. RESULTS: Sagittal joint inclination and craniocervical tilt significantly correlated with both BI and AAD (P<.01). Coronal joint inclination correlated with BI (P=.2). The mean sagittal joint inclination value in control subjects was 87.15±5.65° and in patients with BI and AAD was 127.1±22.05°. The mean craniocervical tilt value in controls was 60.2±9.2° and in patients with BI and AAD was 84.0±15.1°. The mean coronal joint inclination value in control subjects was 110.3±4.23° and in patients with BI and AAD was 121.15±14.6°. CONCLUSION: This study has demonstrated for the first time the important role of joint orientation and its correlation with the severity of BI and AAD and has described new joint indexes.

Extended costotransversectomy to achieve circumferential fusion for pathologies causing thoracic instability.

BACKGROUND CONTEXT: Conventional circumferential stabilization for pathologies causing instability of the thoracic spine requires a two or even a three-staged procedure. The authors present their tertiary care center experience of single-staged procedure to establish a circumferential fusion through an extended costotransversectomy approach. OBJECTIVE: To demonstrate neural canal decompression, removal of the pathology, achieve circumferential fusion, and correcting the deformity through a single procedure. STUDY DESIGN: Prospective and observational. PATIENT SAMPLE: Forty-six patients with pan thoracic column instability due to various pathologies. OUTCOME MEASURES: Neurologic condition was evaluated using American Spinal Injury Association and Eastern Cooperative Oncology Group grading systems. Outcome was evaluated with regard to the decompression of neural canal, correction of deformity, and neurologic improvement. All patients were evaluated for neural canal compromise and degree of kyphosis preoperatively, early, and late postoperatively. METHODS: All patients had severe spinal canal compromise (mean, 59%±9%) and loss of vertebral body height (mean, 55%±10%). A single-stage circumferential fusion was performed (four-level pedicle screw fixation along with a ventral cage fixation after a vertebrectomy or corpectomy) through an extended costotransversectomy approach. RESULTS: The pathologies included trauma (21), tuberculosis (18), hemangioma (2), aneurysmal bone cyst (1), recurrent hemangioendothelioma (1), solitary metastasis (1) and plasmacytoma (1), and neurofibromatosis (1). Thirty-five of 46 patients (76%) demonstrated improvement in the performance status. The major complications included pneumonitis (3), pneumothorax (3) and neurologic deterioration (3; improved in two), deep venous thrombosis (2), and recurrent hemoptysis (1). No implant failures were noted on last radiology follow-up. There were two mortalities; one because of myocardial infarction and another because of respiratory complications. CONCLUSIONS: The following study demonstrated that extended costotrasversectomy approach is a good option for achieving single-staged circumferential fusion for correcting unstable thoracic spine due to both traumatic and nontraumatic pathologies.