Relationship of Cervical Sagittal Vertical Alignment After Sagittal Balance Correction in Adult Spinal Deformity: A Retrospective Radiographic Study.

STUDY DESIGN: Retrospective radiographic study. PURPOSE: Predict the variability of the center of gravity of head (COG) relative to the global cervical sagittal alignment (SVA). BACKGROUND: Cervical lordosis, thoracic kyphosis, lumbar lordosis, and pelvic incidence are considered interrelated, with changes in SVA causing reciprocal changes to bring the head over pelvis. The implications of cervical deformities have generated more interest recently, and it has been shown that poor cervical alignment is associated with poor clinical outcomes. METHODS: Patients were selected from the imaging server of a single institution with adult spinal deformity (ASD) and SVA, who underwent surgical correction from 2008 to 2013. Three observers performed the measurements, and intraclass correlation coefficient (ICC) was measured for inter and intraobserver reliability. Group 1 was patients with unbalanced spines (C7-SVA > 5 cm) preoperatively and corrected to full balanced spine (C7-SVA < 5 cm) until last follow-up. Group 2 was improved in sagittal balance after surgery and maintained SVA correction until last follow-up, but not fully balanced. RESULTS: Fifty-five patients met the inclusion criteria, 42 patients improved in SVA after surgery, and 13 showed no improvement. Twenty-three patients kept full balanced measurements until last follow-up, and 19 patients maintained not-full balanced spine. In group 1, there was no change in pre and postoperative parameters except for C2-CL (21.74° vs 16.91°, P = .033). It was similar in group 2, no differences except for C2-CL (21.67° vs 17.81°, P = .018). CONCLUSION: Parameters in this study failed to yield predictable relationships when compared to changes in SVA. The position of COG may be independent of global SVA. CLINICAL RELEVANCE: This study aims to improve our understanding of the dynamic changes and relationships of the regional and global spinal parameters with regard to spinal deformity corrective surgeries in adults. LEVEL OF EVIDENCE: III.

Posttraumatic Spinal Cord Injury without Radiographic Abnormality.

"Spinal Cord Injury without Radiographic Abnormality" (SCIWORA) is a term that denotes objective clinical signs of posttraumatic spinal cord injury without evidence of fracture or malalignment on plain radiographs and computed tomography (CT) of the spine. SCIWORA is most commonly seen in children with a predilection for the cervical spinal cord due to the increased mobility of the cervical spine, the inherent ligamentous laxity, and the large head-to-body ratio during childhood. However, SCIWORA can also be seen in adults and, in rare cases, the thoracolumbar spinal cord can be affected too. Magnetic resonance imaging (MRI) has become a valuable diagnostic tool in patients with SCIWORA because of its superior ability to identify soft tissue lesions such as cord edema, hematomas and transections, and discoligamentous injuries that may not be visualized in plain radiographs and CT. The mainstay of treatment in patients with SCIWORA is nonoperative management including steroid therapy, immobilization, and avoidance of activities that may increase the risk of exacerbation or recurrent injury. Although the role of operative treatment in SCIWORA can be controversial, surgical alternatives such as decompression and fusion should be considered in selected patients with clinical and MRI evidence of persistent spinal cord compression and instability.

Adult Spinal Deformity: Epidemiology, Health Impact, Evaluation, and Management.

Spinal deformity in the adult is a common medical disorder with a significant and measurable impact on health-related quality of life. The ability to measure and quantify patient self-reported health status with disease-specific and general health status measures, and to correlate health status with radiographic and clinical measures of spinal deformity, has enabled significant advances in the assessment of the impact of deformity on our population, and in the evaluation and management of spinal deformity using an evidence-based approach. There has been a significant paradigm shift in the evaluation and management of patients with adult deformity. The paradigm shift includes development of validated, disease-specific measures of health status, recognition of deformity in the sagittal plane as a primary determinant of health status, and information on results of operative and medical/interventional management strategies for adults with spinal deformity. Since its inception in 1966, the Scoliosis Research Society (SRS) has been an international catalyst for improving the research and care for patients of all ages with spinal deformity. The SRS Adult Spinal Deformity Committee serves the mission of developing and defining an evidence-based approach to the evaluation and management of adult spinal deformity. The purpose of this overview from the SRS Adult Deformity Committee is to provide current information on the epidemiology and impact of adult deformity, and to provide patients, physicians, and policy makers a guide to the evidence-based evaluation and management of patients with adult deformity.

Correlation of Pelvic and Spinal Parameters in Adult Deformity Patients With Neutral Sagittal Balance.

STUDY DESIGN: Retrospective measurement of spinal and pelvic parameters in adult spinal deformity patients. OBJECTIVE: To correlate spinal and pelvic parameters in adult spinal deformity patients who were in neutral spinal balance. SUMMARY AND BACKGROUND DATA: It is believed that sagittal spinal balance is influenced by both spinal and pelvic parameters, which are closely interrelated as manifested by the reciprocal changes seen when any of the interrelationships was altered. New parameters including proximal thoracic slope (PTS), proximal thoracic tilt, thoracic apical tilt, and coxo-spinal angle (CSA) were studied and correlated with previously studied spinal and pelvic parameters. METHODS: One thousand patients who had undergone standing scoliosis views from 2007 to 2010 were screened. A total of 70 patients, 29 with a diagnosis of degenerative scoliosis and 41 with the diagnosis of adult idiopathic scoliosis, were analyzed for various spinal and spinopelvic parameters. Linear regression analysis was performed. RESULTS: Thoracic kyphosis (TK) plus sacral slope (SS) had as strong a correlation with lumbar lordosis (LL) (r = 0.871; p < .000) as with pelvic incidence. The ratio LL / (TK + SS) yielded a constant ratio of 0.74 for the balanced spine. Pelvic incidence ± 9 = LL. Lumbar lordosis × 0.74 = TK. Coxo-spinal angle correlated with TK (r = 0.404; p = .000) and CSA / TK yielded a constant ratio in balanced spines. Proximal thoracic slope and thoracic apical tilt strongly correlated with TK (R = 0.793; p = 0.000). Proximal thoracic slope allows introduction of the spinal equation, PTS + LL = SS + TK, which is based on the geometric principle that when measuring angles between 2 horizontal parallel lines the sum of the angles in opposite directions is equal. CONCLUSION: The spinal equation may predict ideal spinal and pelvic parameters that may aid in preventing complications such as proximal junctional failure.

An extension-distraction injury of the thoracic spine with traumatic partial correction of thoracic kyphosis.

Study Design The study is a case report. Objective The authors aim to report an unusual injury pattern in a patient previously treated for thoracic kyphoscoliosis. Methods A postoperative (computed tomography) CT of a healthy 24-year-old man who underwent posterior instrumentation and fusion for a kyphoscoliosis deformity was compared with a CT performed after a motor vehicle accident (MVA) 1 year later, which resulted in an extension-distraction injury of T8 with no neurologic deficit. Cobb angles of the thoracic sagittal images of both CTs were measured using a digital measuring device and the values were recorded. Results Initial postoperative sagittal CT images demonstrate a 67-degree residual thoracic kyphosis compared with the post-MVA sagittal CT images, which reveal a 54-degree thoracic kyphosis, a 13-degree improvement in sagittal alignment. Conclusion It is unusual for a patient with long posterior instrumentation of the spine to sustain a spinal fracture without breakage of the rods, which were 6-mm nickel-titanium alloy with two crosslinks. Although sustaining plastic deformation, the rods maintained their integrity to the degree that the patient required no subsequent treatment to his spine at 12 months follow-up. It is rare to sustain a vertebral fracture without implant failure, which occurred in this case.

Scoliosis Research Society-Schwab adult spinal deformity classification: a validation study.

STUDY DESIGN: Inter- and intra-rater variability study. OBJECTIVE: On the basis of a Scoliosis Research Society effort, this study seeks to determine whether the new adult spinal deformity (ASD) classification system is clear and reliable. SUMMARY OF BACKGROUND DATA: A classification of adult ASD can serve several purposes, including consistent characterization of a clinical entity, a basis for comparing different treatments, and recommended treatments. Although pediatric scoliosis classifications are well established, an ASD classification is still being developed. A previous classification developed by Schwab et al has met with clinical relevance but did not include pelvic parameters, which have shown substantial correlation with health-related quality of life measures in recent studies. METHODS: Initiated by the Scoliosis Research Society Adult Deformity Committee, this study revised a previously published classification to include pelvic parameters. Modifier cutoffs were determined using health-related quality of life analysis from a multicenter database of adult deformity patients. Nine readers graded 21 premarked cases twice each, approximately 1 week apart. Inter- and intra-rater variability and agreement were determined for curve type and each modifier separately. Fleiss' kappa was used for reliability measures, with values of 0.00 to 0.20 considered slight, 0.21 to 0.40 fair, 0.41 to 0.60 moderate, 0.61 to 0.80 substantial, and 0.81 to 1.00 almost perfect agreement. RESULTS: Inter-rater kappa for curve type was 0.80 and 0.87 for the 2 readings, respectively, with modifier kappas of 0.75 and 0.86, 0.97 and 0.98, and 0.96 and 0.96 for pelvic incidence minus lumbar lordosis (PI-LL), pelvic tilt (PT), and sagittal vertical axis (SVA), respectively. By the second reading, curve type was identified by all readers consistently in 66.7%, PI-LL in 71.4%, PT in 95.2%, and SVA in 90.5% of cases. Intra-rater kappa averaged 0.94 for curve type, 0.88 for PI-LL, 0.97 for PT, and 0.97 for SVA across all readers. CONCLUSION: Data from this study show that there is excellent inter- and intra-rater reliability and inter-rater agreement for curve type and each modifier. The high degree of reliability demonstrates that applying the classification system is easy and consistent.