Browsing by Author "Ryan, Devon J"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Open Access Association of myelopathy scores with cervical sagittal balance and normalized spinal cord volume: analysis of 56 preoperative cases from the AOSpine North America Myelopathy study.(Spine, 2013-10) Smith, Justin S; Lafage, Virginie; Ryan, Devon J; Shaffrey, Christopher I; Schwab, Frank J; Patel, Alpesh A; Brodke, Darrel S; Arnold, Paul M; Riew, K Daniel; Traynelis, Vincent C; Radcliff, Kris; Vaccaro, Alexander R; Fehlings, Michael G; Ames, Christopher PStudy design
Post hoc analysis of prospectively collected data.Objective
Development of methods to determine in vivo spinal cord dimensions and application to correlate preoperative alignment, myelopathy, and health-related quality-of-life scores in patients with cervical spondylotic myelopathy (CSM).Summary of background data
CSM is the leading cause of spinal cord dysfunction. The association between cervical alignment, sagittal balance, and myelopathy has not been well characterized.Methods
This was a post hoc analysis of the prospective, multicenter AOSpine North America CSM study. Inclusion criteria for this study required preoperative cervical magnetic resonance imaging (MRI) and neutral sagittal cervical radiography. Techniques for MRI assessment of spinal cord dimensions were developed. Correlations between imaging and health-related quality-of-life scores were assessed.Results
Fifty-six patients met inclusion criteria (mean age = 55.4 yr). The modified Japanese Orthopedic Association (mJOA) scores correlated with C2-C7 sagittal vertical axis (SVA) (r = -0.282, P = 0.035). Spinal cord volume correlated with cord length (r = 0.472, P < 0.001) and cord average cross-sectional area (r = 0.957, P < 0.001). For all patients, no correlations were found between MRI measurements of spinal cord length, volume, mean cross-sectional area or surface area, and outcomes. For patients with cervical lordosis, mJOA scores correlated positively with cord volume (r = 0.366, P = 0.022), external cord area (r = 0.399, P = 0.012), and mean cross-sectional cord area (r = 0.345, P = 0.031). In contrast, for patients with cervical kyphosis, mJOA scores correlated negatively with cord volume (r = -0.496, P = 0.043) and mean cross-sectional cord area (r = -0.535, P = 0.027).Conclusion
This study is the first to correlate cervical sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment. It is interesting to note that sagittal balance but not kyphosis is tied to myelopathy score. Future work will correlate alignment changes to cord morphology changes and myelopathy outcomes. SUMMARY STATEMENTS: This is the first study to correlate sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment.Item Open Access TheT1 pelvic angle, a novel radiographic measure of global sagittal deformity, accounts for both spinal inclination and pelvic tilt and correlates with health-related quality of life.(The Journal of bone and joint surgery. American volume, 2014-10) Protopsaltis, Themistocles; Schwab, Frank; Bronsard, Nicolas; Smith, Justin S; Klineberg, Eric; Mundis, Gregory; Ryan, Devon J; Hostin, Richard; Hart, Robert; Burton, Douglas; Ames, Christopher; Shaffrey, Christopher; Bess, Shay; Errico, Thomas; Lafage, Virginie; International Spine Study GroupBackground
Adult spinal deformity is a prevalent cause of pain and disability. Established measures of sagittal spinopelvic alignment such as sagittal vertical axis and pelvic tilt can be modified by postural compensation, including pelvic retroversion, knee flexion, and the use of assistive devices for standing. We introduce the T1 pelvic angle, a novel measure of sagittal alignment that simultaneously accounts for both spinal inclination and pelvic retroversion. The purpose of this study was to investigate the relationship of the T1 pelvic angle and other established sagittal alignment measures and to correlate these parameters with health-related quality-of-life measures.Methods
This is a multicenter, prospective, cross-sectional analysis of consecutive patients with adult spinal deformity. Inclusion criteria were adult spinal deformity, an age of greater than eighteen years, and any of the following: scoliosis, a Cobb angle of ≥ 20°, sagittal vertical axis of ≥ 5 cm, thoracic kyphosis of ≥ 60°, and pelvic tilt of ≥ 25°. Clinical measures of disability included the Oswestry Disability Index (ODI), Scoliosis Research Society (SRS)-22, and Short Form-36 (SF-36) questionnaires.Results
Five hundred and fifty-nine consecutive patients with adult spinal deformity (mean age, 52.5 years) were enrolled. The T1 pelvic angle correlated with the sagittal vertical axis (r = 0.837), pelvic incidence minus lumbar lordosis (r = 0.889), and pelvic tilt (0.933). Categorizing the patients by increasing T1 pelvic angle (<10°, 10° to 20°, 21° to 30°, and > 30°) revealed a significant and progressive worsening in health-related quality of life (p < 0.001 for all). The T1 pelvic angle and sagittal vertical axis correlated with the ODI (0.435 and 0.455), SF-36 Physical Component Summary (-0.445 and -0.458), and SRS (-0.358 and -0.383) (p < 0.001 for all). Utilizing a linear regression analysis, a T1 pelvic angle of 20° corresponded to a severe disability (an ODI of >40), and the meaningful change in T1 pelvic angle corresponding to one minimal clinically important difference was 4.1° on the ODI.Conclusions
The T1 pelvic angle correlates with health-related quality of life in patients with adult spinal deformity. The T1 pelvic angle is related to both pelvic tilt and sagittal vertical axis; however, unlike sagittal vertical axis, it does not vary on the basis of the extent of pelvic retroversion or patient support in standing. Since the T1 pelvic angle is an angular and not a linear measure, it does not require calibration of the radiograph. Thus, the T1 pelvic angle measures sagittal deformity independent of many postural compensatory mechanisms, and it can be useful as a preoperative planning tool, with a target T1 pelvic angle of < 14°.Level of evidence
Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.