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Do Perioperative Spinal Deformity Parameters and Junctional Mechanical Failures Predict the Development of Proximal Junctional Kyphosis after Long Thoracolumbar Fusions for Adult Spinal Deformity?
Proceedings of the NASS 30th Annual Meeting / The Spine Journal 15 (2015) 87S–267S 7
Kansas Medical Center, Kansas City, KS, US; Oregon Health & Science University, Portland, OR, US; 8Washington University, Saint Louis, MO, US; 9San Francisco, CA, US; 10University of Minnesota, Minneapolis, MN, US; 11Rocky Mountain Scoliosis and Spine, Denver, CO, US; 12University of Virginia, Charlottesville, VA, US; 13UVA Health System, Charlottesville, VA, US; 14University of California San Francisco, San Francisco, CA, US BACKGROUND CONTEXT: Operative management of adult spinal deformity (ASD) repeatedly demonstrates improvements in HRQOL over nonoperative treatment. However, little is reported regarding the qualityadjusted-life-year (QALY) improvements following surgical correction of ASD. PURPOSE: The purpose of this study was to evaluate the QALY increases following the operative treatment of ASD compared with nonoperative treatment. STUDY DESIGN/SETTING: Retrospective review of prospective multicenter ASD database. PATIENT SAMPLE: 479 patients with ASD. OUTCOME MEASURES: QALY from SF6D. METHODS: Inclusion criteria: $18 years, ASD. Individual SF36 scores were converted to SF6D utility values based on an externally validated and previously published nonparametric Bayesian model. These were used to calculate QALYs gained or lost at minimum 2 years from the baseline utility value. A subanalysis was conducted on the available patients in the cohort with complete 1, 2 and 3-year SF36 scores to establish a trend in QALY changes. RESULTS: 365 operative and 469 nonop patients were eligible for 2-year follow up and 479 patients were included (OP:258 (70.7%), NONOP:221(47.1%). OP had significantly worse health utility values (0.54560.118 vs 0.65760.114, p!0.0001), and larger QALY gained (0.13960.253 vs -0.00460.209, p!0.0001). OP had lower QALY at min 2 years (1.2860.330 vs 1.3960.374, p50.0014). 179 patients (OP:106, NONOP:73) had complete 1,2 and 3yr SF36 scores and were included in the subanalysis. Of these patients, both groups had statistically similar mean QALYs at all time points (OP vs NONOP, pO0.05): 1 year (0.64860.102 vs 0.64560.090), 2 year (1.32 60.232 vs 1.2760.204), and 3 year (1.9760.379 vs 1.9360.303). OP patients had a significantly larger increase in QALYs (from baseline) at 1, 2, and 3 years compared with NONOP: 1 year (0.08460.113 vs 0.01160.086, p!0.0001), 2 year (0.17960.240 vs 0.00560.186, p!0.0001), and 3 year (0.25860.354 vs 0.02060.258, p!0.0001). CONCLUSIONS: The operative treatment of adult spinal deformity results in significant increases in QALYs gained at minimum 2 years postop as well as at the 1-, 2-, and 3-year time points compared to nonoperative management. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.08.034
Friday, October 16, 2015 3:50 – 4:50 pm Thoracolumbar Spinal Alignment 148. The ALL Biomechanically Affects Lateral Hyperlordotic Interbody Spacer Lordosis Correction Noelle Klocke, MS1, Heidi M. Hullinger, MD2, Mir Hussain1, Sean Jenkins, BS1, Yiwei Cai1, Brandon Bucklen, PhD1; 1Globus Medical, Audubon, PA, US; 2Summit, NJ, US BACKGROUND CONTEXT: The anterior longitudinal ligament (ALL) may be left intact during standard lateral lumbar interbody fusion
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(LLIF) procedures for stability and to prevent anterior expulsion of the device. However, if lordosis restoration is a priority, the benefits of using a hyperlordotic interbody spacer may not be fully realized without resection. PURPOSE: To investigate the changes in L4-5 Cobb angles when using varying lordotic lateral interbody spacers within cadaveric specimens and determine whether hyperlordotic spacers necessitate ALL resection in order to achieve the desired correction. STUDY DESIGN/SETTING: Cadaveric fluoroscopic investigation. PATIENT SAMPLE: N56 cadaveric specimens. OUTCOME MEASURES: Fluoroscopic Cobb angles. METHODS: This biomechanical study investigated changes in Cobb angles using hyperlordotic spacers both with and without an intact ALL. Six fresh-frozen, L4-5 cadaveric specimens were cleaned of excess soft tissues and fixed using Bondo autobody filler (MarHyde Corporation, Inc.) such that the superior L5 endplate was parallel with the horizon. Each specimen was then placed into a custom fixture, which applied forces experienced by L4-5 during supine intraoperative (27.5lb) and upright standing (112.5lb) positions. Lateral fluoroscopic images captured absolute changes from the intact Cobb angle for each inserted static 11mm hyperlordotic LLIF spacer (0,6,10,20 , Globus Medical, Inc.), both alone (initial surgical angle) and with posterior reduction using bilateral pedicle screws (standing weight). RESULTS: The Cobb angles achieved with a resected ALL ranged 0.6 5.4 greater than the same spacers used with the ALL intact under both simulated supine and standing conditions; the difference between the two groups decreased with increasing angulation. CONCLUSIONS: Achievable lordosis correction was smaller when the ALL remained intact across all tested hyperlodotic spacers. However, average postsurgical correction was nearly equivalent between intact and resected ALL states when a 20 hyperlordotic spacer was used. The use of angled interbody spacers had a positive impact on increasing lordosis correction, especially following full posterior reduction. While ALL resection may allow for improved lordosis correction, anterior expulsion and other patient safety factors should always be considered. FDA DEVICE/DRUG STATUS: Transcontinental-M (Approved for this indication). http://dx.doi.org/10.1016/j.spinee.2015.07.181
149. Do Perioperative Spinal Deformity Parameters and Junctional Mechanical Failures Predict the Development of Proximal Junctional Kyphosis after Long Thoracolumbar Fusions for Adult Spinal Deformity? Murat S. Eksi, MD1, Alexander A. Theologis, MD2, Altug Yucekul, MD3, Murat Pekmezci, MD4, Shane Burch, MD1, Sigurd H. Berven, MD4, Bobby Tay, MD1, Dean Chou, MD1, Christopher P. Ames, MD1, Vedat Deviren, MD1; 1University of California San Francisco, San Francisco, CA, US; 2University of California San Francisco, San Francisco General Hospital Orthopaedic Trauma Institute, San Francisco, CA, US; 3Ankara, Turkey; 4University of California San Francisco Department of Orthopaedic Surgery, San Francisco, CA, US; 5San Francisco, CA, US BACKGROUND CONTEXT: Proximal junctional kyphosis (PJK) is the most common complication following adult spinal deformity (ASD) surgery, although unique demographic and perioperative radiographic spinal deformity parameters for patients who develop PJK and those who do not after ASD operation are not well defined. PURPOSE: To assess unique demographic and perioperative radiographic spinal deformity parameters associated with PJK after ASD operation. STUDY DESIGN/SETTING: Retrospective cohort analysis. PATIENT SAMPLE: Adults with spinal deformity who underwent long thoracolumbar fusions.
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
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Proceedings of the NASS 30th Annual Meeting / The Spine Journal 15 (2015) 87S–267S
OUTCOME MEASURES: Spinal deformity parameters, including pelvic tilt, pelvic incidence, sacral slope, lumbar lordosis, lumbopelvic mismatch, thoracic kyphosis, sagittal vertical axis, thoracic and lumbar Cobb angles, and proximal junctional angles. METHODS: A retrospective study of consecutive patients who underwent thoracolumbar fusions for ASD between 2003 and 2011 at a single institution was performed. Inclusion criteria were: age O18 years, instrumentation extending from the pelvis to L1 or above, and minimum 2 years follow-up. Patients with infections were excluded. Radiographic analysis included: pre- and postoperative spinal deformity parameters and mechanical failures at the proximal junction of fusions were assessed. Patients with and without PJK were compared. Radiographic PJK was defined as: (1) O10 of proximal junctional angle (PJA, between UIV and UIVþ2) and (2) O10 increase of PJA compared to preop PJA. RESULTS: Three-hundred-forty patients (male: 86, female: 254, average age: 63610 years) met inclusion criteria. One-hundred seventy-six patients (51.8%) developed PJK of whom 104 (59%) had a proximal junction fracture, 39 had proximal junctional screw pullout (22%) and 18 had spondylolisthesis (10.2%). Non-PJK patients (n5164) had significantly fewer junctional fractures (n521; 16%), screw pullout (n510; 7.8%), and spondylolisthesis (n50). While only 27% of patients with PJK required revision surgery. Compared to those without PJK, patients who developed PJK were significantly older (61.09 vs 65.21; p!0.001 ) and had significantly greater thoracic kyphosis (35.02 vs 42 , p!0.001; 37.92 vs 45.41 , p!0.001), lumbar lordosis (45.25 vs 48.87 , p50.028; 43.62 vs 48.77 , p50.001) and less LL-PI mismatch (8.99 6 14.52 vs 4.96 6 16.409 , p50.021;10.45 6 14.203 vs 5.87 6 15.72 , p50.006) on the first erect radiographic and at final follow-up. All other pre- and postoperative radiographs were statistically similar between the two groups. CONCLUSIONS: After long fusions for ASD surgery, PJK occurred in more than 50% of patients, of which 27.2% were revised. Junctional mechanical failures (fracture, screw pullout, spondylolisthesis) often do not warrant revision surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.07.182
150. Unlocking TPA’s Clinical and Sagittal Significance by Analyzing its Relation to Pelvic Tilt Virginie Lafage, PhD1, Barthelemy Liabaud, MD2, Renaud Lafage1, Jonathan H. Oren, MD1, Shaleen Vira, MD1, Bradley Harris, JD1, Matthew Spiegel, BS, MD3, Bassel G. Diebo, MD2, Elizabeth Tanzi, ARNP4, Themistocles S. Protopsaltis, MD1, Thomas J. Errico, MD5, Frank J. Schwab, MD1; 1New York University Hospital for Joint Diseases, New York, NY, US; 2New York University, New York, NY, US; 3Woodmere, NY, US; 4New York, NY, US; 5New York University Medical Center, New York, NY, US BACKGROUND CONTEXT: TPA (T1 pelvic angle) is a valuable perioperative planning tool that accounts for both pelvic tilt (PT) and trunk inclination. While this parameter correlates with patient reported outcomes, it is limited as a standalone parameter because it does not distinguish patients’ ability to compensate with pelvic retroversion. PURPOSE: Investigate the TPA and its close relation with pelvic tilt in order to assess patients HRQOL (health-related quality of life) with a given TPA and a varying PT. STUDY DESIGN/SETTING: Retrospective cohort. PATIENT SAMPLE: Single-center study of 230 patients (58.7615.5 years old, 60% females) with full body radiographs, HRQOL forms and TPA$10 . OUTCOME MEASURES: Sagittal spino-pelvic parameters including SVA, PT, PI-LL, and TPA, and the following health related quality of life questionnaires: ODI and EQ-5D.
METHODS: Proportions of PT to TPA (PTp5PT/TPA) and T1SPi to TPA (T1SPip5T1SPi/TPA) were calculated and investigated against increased values of TPA. Then, two sub-groups of similar TPA were created (HighPT and LowPT) based on mean (PTp)60.5 standard deviation. HighPT and LowPT were compared across the entire cohort using an unpaired T-test. RESULTS: Mean sagittal parameters included: PI-LL 12.3616.3 , SVA 41649mm, TPA 21.9610.1 and PT 24.468.6 . The analysis of PTp distribution revealed a decrease in PT recruitment as TPA increases (137639% for patients with TPA!15 , 87615% for patients with TPAO40 ). Comparing LowPT (n557) with HighPT (n569) revealed that for a similar TPA (24.1 vs 22.1 , p50.308), patients with LowPT (and therefore little compensatory PT) had significantly worse HRQOL scores in terms of ODI (45 vs 32 in HighPT; p50.002) and EQ-5D (9.7 vs 8.5 in HighPT, p50.003). CONCLUSIONS: While TPA captures the severity of deformity, disability is a product of deformity severity and the inability to recruit compensatory mechanisms. TPA measures the severity of the thoracolumbar deformity separate from pelvic compensation. Therefore, to develop a complete picture of standing sagittal alignment, TPA should be considered in conjunction with PT to convey the full radiological and clinical picture. Failing to do so potentially results in inadequate assessment of a patient’s disability. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.07.183
151. When Does Compensation for Lumbar Stenosis Become a Deformity? Virginie Lafage, PhD1, Aaron J. Buckland, MBBS, FRACS1, Shaleen Vira, MD1, Jonathan H. Oren, MD1, Renaud Lafage1, Bradley Harris, JD1, Matthew Spiegel, BS, MD2, Bassel G. Diebo, MD3, Barthelemy Liabaud, MD3, Themistocles S. Protopsaltis, MD1, Frank J. Schwab, MD1, Thomas J. Errico, MD4, John A. Bendo, MD5; 1New York University Hospital for Joint Diseases, New York, NY, US; 2Woodmere, NY, US; 3New York University, New York, NY, US; 4New York University Medical Center, New York, NY, US; 5New York University Hospital for Joint Diseases Spine Center, New York, NY, US BACKGROUND CONTEXT: Degenerative lumbar stenosis (DLS) patients adopt forward-bending posture as a compensatory mechanism, increasing spinal canal and foraminal volume. Previous data show laminectomy 6 short segment fusion results in improvement of sagittal vertical axis (SVA), pelvic tilt (PT) and PI-LL (pelvic incidence-lumbar lordosis) mismatch by SRS-Schwab classification in !25% of patients. The magnitude of deformity for which a DLS patient should have realignment remains unknown. PURPOSE: To identify differences in compensatory mechanisms between DLS and adult spinal deformity (ASD) patients with increasing, and to identify at what point DLS patients recruit ASD-type compensatory mechanisms. STUDY DESIGN/SETTING: Retrospective clinical and radiological review. PATIENT SAMPLE: Baseline X-ray images of 239 patients without spinal instrumentation, with the clinical radiological and diagnosis of DLS or ASD were assessed for patterns of spino-pelvic compensatory mechanisms. Patients were stratified by sagittal vertical axis (SVA) by the Schwab-SRS classification. OUTCOME MEASURES: Radiographic spino-pelvic parameters were measured in the DLS and ASD groups, including SVA, PI-LL, T1SPi, TPA and PT. METHODS: Patients were identified using a single-institution database with sole diagnosis of DLS, O40 years and if they had any of the following: PTO25 , SVAO5cm, thoracic kyphosis (TK)O60 or PI-LL
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
Kansas Medical Center, Kansas City, KS, US; Oregon Health & Science University, Portland, OR, US; 8Washington University, Saint Louis, MO, US; 9San Francisco, CA, US; 10University of Minnesota, Minneapolis, MN, US; 11Rocky Mountain Scoliosis and Spine, Denver, CO, US; 12University of Virginia, Charlottesville, VA, US; 13UVA Health System, Charlottesville, VA, US; 14University of California San Francisco, San Francisco, CA, US BACKGROUND CONTEXT: Operative management of adult spinal deformity (ASD) repeatedly demonstrates improvements in HRQOL over nonoperative treatment. However, little is reported regarding the qualityadjusted-life-year (QALY) improvements following surgical correction of ASD. PURPOSE: The purpose of this study was to evaluate the QALY increases following the operative treatment of ASD compared with nonoperative treatment. STUDY DESIGN/SETTING: Retrospective review of prospective multicenter ASD database. PATIENT SAMPLE: 479 patients with ASD. OUTCOME MEASURES: QALY from SF6D. METHODS: Inclusion criteria: $18 years, ASD. Individual SF36 scores were converted to SF6D utility values based on an externally validated and previously published nonparametric Bayesian model. These were used to calculate QALYs gained or lost at minimum 2 years from the baseline utility value. A subanalysis was conducted on the available patients in the cohort with complete 1, 2 and 3-year SF36 scores to establish a trend in QALY changes. RESULTS: 365 operative and 469 nonop patients were eligible for 2-year follow up and 479 patients were included (OP:258 (70.7%), NONOP:221(47.1%). OP had significantly worse health utility values (0.54560.118 vs 0.65760.114, p!0.0001), and larger QALY gained (0.13960.253 vs -0.00460.209, p!0.0001). OP had lower QALY at min 2 years (1.2860.330 vs 1.3960.374, p50.0014). 179 patients (OP:106, NONOP:73) had complete 1,2 and 3yr SF36 scores and were included in the subanalysis. Of these patients, both groups had statistically similar mean QALYs at all time points (OP vs NONOP, pO0.05): 1 year (0.64860.102 vs 0.64560.090), 2 year (1.32 60.232 vs 1.2760.204), and 3 year (1.9760.379 vs 1.9360.303). OP patients had a significantly larger increase in QALYs (from baseline) at 1, 2, and 3 years compared with NONOP: 1 year (0.08460.113 vs 0.01160.086, p!0.0001), 2 year (0.17960.240 vs 0.00560.186, p!0.0001), and 3 year (0.25860.354 vs 0.02060.258, p!0.0001). CONCLUSIONS: The operative treatment of adult spinal deformity results in significant increases in QALYs gained at minimum 2 years postop as well as at the 1-, 2-, and 3-year time points compared to nonoperative management. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.08.034
Friday, October 16, 2015 3:50 – 4:50 pm Thoracolumbar Spinal Alignment 148. The ALL Biomechanically Affects Lateral Hyperlordotic Interbody Spacer Lordosis Correction Noelle Klocke, MS1, Heidi M. Hullinger, MD2, Mir Hussain1, Sean Jenkins, BS1, Yiwei Cai1, Brandon Bucklen, PhD1; 1Globus Medical, Audubon, PA, US; 2Summit, NJ, US BACKGROUND CONTEXT: The anterior longitudinal ligament (ALL) may be left intact during standard lateral lumbar interbody fusion
161S
(LLIF) procedures for stability and to prevent anterior expulsion of the device. However, if lordosis restoration is a priority, the benefits of using a hyperlordotic interbody spacer may not be fully realized without resection. PURPOSE: To investigate the changes in L4-5 Cobb angles when using varying lordotic lateral interbody spacers within cadaveric specimens and determine whether hyperlordotic spacers necessitate ALL resection in order to achieve the desired correction. STUDY DESIGN/SETTING: Cadaveric fluoroscopic investigation. PATIENT SAMPLE: N56 cadaveric specimens. OUTCOME MEASURES: Fluoroscopic Cobb angles. METHODS: This biomechanical study investigated changes in Cobb angles using hyperlordotic spacers both with and without an intact ALL. Six fresh-frozen, L4-5 cadaveric specimens were cleaned of excess soft tissues and fixed using Bondo autobody filler (MarHyde Corporation, Inc.) such that the superior L5 endplate was parallel with the horizon. Each specimen was then placed into a custom fixture, which applied forces experienced by L4-5 during supine intraoperative (27.5lb) and upright standing (112.5lb) positions. Lateral fluoroscopic images captured absolute changes from the intact Cobb angle for each inserted static 11mm hyperlordotic LLIF spacer (0,6,10,20 , Globus Medical, Inc.), both alone (initial surgical angle) and with posterior reduction using bilateral pedicle screws (standing weight). RESULTS: The Cobb angles achieved with a resected ALL ranged 0.6 5.4 greater than the same spacers used with the ALL intact under both simulated supine and standing conditions; the difference between the two groups decreased with increasing angulation. CONCLUSIONS: Achievable lordosis correction was smaller when the ALL remained intact across all tested hyperlodotic spacers. However, average postsurgical correction was nearly equivalent between intact and resected ALL states when a 20 hyperlordotic spacer was used. The use of angled interbody spacers had a positive impact on increasing lordosis correction, especially following full posterior reduction. While ALL resection may allow for improved lordosis correction, anterior expulsion and other patient safety factors should always be considered. FDA DEVICE/DRUG STATUS: Transcontinental-M (Approved for this indication). http://dx.doi.org/10.1016/j.spinee.2015.07.181
149. Do Perioperative Spinal Deformity Parameters and Junctional Mechanical Failures Predict the Development of Proximal Junctional Kyphosis after Long Thoracolumbar Fusions for Adult Spinal Deformity? Murat S. Eksi, MD1, Alexander A. Theologis, MD2, Altug Yucekul, MD3, Murat Pekmezci, MD4, Shane Burch, MD1, Sigurd H. Berven, MD4, Bobby Tay, MD1, Dean Chou, MD1, Christopher P. Ames, MD1, Vedat Deviren, MD1; 1University of California San Francisco, San Francisco, CA, US; 2University of California San Francisco, San Francisco General Hospital Orthopaedic Trauma Institute, San Francisco, CA, US; 3Ankara, Turkey; 4University of California San Francisco Department of Orthopaedic Surgery, San Francisco, CA, US; 5San Francisco, CA, US BACKGROUND CONTEXT: Proximal junctional kyphosis (PJK) is the most common complication following adult spinal deformity (ASD) surgery, although unique demographic and perioperative radiographic spinal deformity parameters for patients who develop PJK and those who do not after ASD operation are not well defined. PURPOSE: To assess unique demographic and perioperative radiographic spinal deformity parameters associated with PJK after ASD operation. STUDY DESIGN/SETTING: Retrospective cohort analysis. PATIENT SAMPLE: Adults with spinal deformity who underwent long thoracolumbar fusions.
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
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Proceedings of the NASS 30th Annual Meeting / The Spine Journal 15 (2015) 87S–267S
OUTCOME MEASURES: Spinal deformity parameters, including pelvic tilt, pelvic incidence, sacral slope, lumbar lordosis, lumbopelvic mismatch, thoracic kyphosis, sagittal vertical axis, thoracic and lumbar Cobb angles, and proximal junctional angles. METHODS: A retrospective study of consecutive patients who underwent thoracolumbar fusions for ASD between 2003 and 2011 at a single institution was performed. Inclusion criteria were: age O18 years, instrumentation extending from the pelvis to L1 or above, and minimum 2 years follow-up. Patients with infections were excluded. Radiographic analysis included: pre- and postoperative spinal deformity parameters and mechanical failures at the proximal junction of fusions were assessed. Patients with and without PJK were compared. Radiographic PJK was defined as: (1) O10 of proximal junctional angle (PJA, between UIV and UIVþ2) and (2) O10 increase of PJA compared to preop PJA. RESULTS: Three-hundred-forty patients (male: 86, female: 254, average age: 63610 years) met inclusion criteria. One-hundred seventy-six patients (51.8%) developed PJK of whom 104 (59%) had a proximal junction fracture, 39 had proximal junctional screw pullout (22%) and 18 had spondylolisthesis (10.2%). Non-PJK patients (n5164) had significantly fewer junctional fractures (n521; 16%), screw pullout (n510; 7.8%), and spondylolisthesis (n50). While only 27% of patients with PJK required revision surgery. Compared to those without PJK, patients who developed PJK were significantly older (61.09 vs 65.21; p!0.001 ) and had significantly greater thoracic kyphosis (35.02 vs 42 , p!0.001; 37.92 vs 45.41 , p!0.001), lumbar lordosis (45.25 vs 48.87 , p50.028; 43.62 vs 48.77 , p50.001) and less LL-PI mismatch (8.99 6 14.52 vs 4.96 6 16.409 , p50.021;10.45 6 14.203 vs 5.87 6 15.72 , p50.006) on the first erect radiographic and at final follow-up. All other pre- and postoperative radiographs were statistically similar between the two groups. CONCLUSIONS: After long fusions for ASD surgery, PJK occurred in more than 50% of patients, of which 27.2% were revised. Junctional mechanical failures (fracture, screw pullout, spondylolisthesis) often do not warrant revision surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.07.182
150. Unlocking TPA’s Clinical and Sagittal Significance by Analyzing its Relation to Pelvic Tilt Virginie Lafage, PhD1, Barthelemy Liabaud, MD2, Renaud Lafage1, Jonathan H. Oren, MD1, Shaleen Vira, MD1, Bradley Harris, JD1, Matthew Spiegel, BS, MD3, Bassel G. Diebo, MD2, Elizabeth Tanzi, ARNP4, Themistocles S. Protopsaltis, MD1, Thomas J. Errico, MD5, Frank J. Schwab, MD1; 1New York University Hospital for Joint Diseases, New York, NY, US; 2New York University, New York, NY, US; 3Woodmere, NY, US; 4New York, NY, US; 5New York University Medical Center, New York, NY, US BACKGROUND CONTEXT: TPA (T1 pelvic angle) is a valuable perioperative planning tool that accounts for both pelvic tilt (PT) and trunk inclination. While this parameter correlates with patient reported outcomes, it is limited as a standalone parameter because it does not distinguish patients’ ability to compensate with pelvic retroversion. PURPOSE: Investigate the TPA and its close relation with pelvic tilt in order to assess patients HRQOL (health-related quality of life) with a given TPA and a varying PT. STUDY DESIGN/SETTING: Retrospective cohort. PATIENT SAMPLE: Single-center study of 230 patients (58.7615.5 years old, 60% females) with full body radiographs, HRQOL forms and TPA$10 . OUTCOME MEASURES: Sagittal spino-pelvic parameters including SVA, PT, PI-LL, and TPA, and the following health related quality of life questionnaires: ODI and EQ-5D.
METHODS: Proportions of PT to TPA (PTp5PT/TPA) and T1SPi to TPA (T1SPip5T1SPi/TPA) were calculated and investigated against increased values of TPA. Then, two sub-groups of similar TPA were created (HighPT and LowPT) based on mean (PTp)60.5 standard deviation. HighPT and LowPT were compared across the entire cohort using an unpaired T-test. RESULTS: Mean sagittal parameters included: PI-LL 12.3616.3 , SVA 41649mm, TPA 21.9610.1 and PT 24.468.6 . The analysis of PTp distribution revealed a decrease in PT recruitment as TPA increases (137639% for patients with TPA!15 , 87615% for patients with TPAO40 ). Comparing LowPT (n557) with HighPT (n569) revealed that for a similar TPA (24.1 vs 22.1 , p50.308), patients with LowPT (and therefore little compensatory PT) had significantly worse HRQOL scores in terms of ODI (45 vs 32 in HighPT; p50.002) and EQ-5D (9.7 vs 8.5 in HighPT, p50.003). CONCLUSIONS: While TPA captures the severity of deformity, disability is a product of deformity severity and the inability to recruit compensatory mechanisms. TPA measures the severity of the thoracolumbar deformity separate from pelvic compensation. Therefore, to develop a complete picture of standing sagittal alignment, TPA should be considered in conjunction with PT to convey the full radiological and clinical picture. Failing to do so potentially results in inadequate assessment of a patient’s disability. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.07.183
151. When Does Compensation for Lumbar Stenosis Become a Deformity? Virginie Lafage, PhD1, Aaron J. Buckland, MBBS, FRACS1, Shaleen Vira, MD1, Jonathan H. Oren, MD1, Renaud Lafage1, Bradley Harris, JD1, Matthew Spiegel, BS, MD2, Bassel G. Diebo, MD3, Barthelemy Liabaud, MD3, Themistocles S. Protopsaltis, MD1, Frank J. Schwab, MD1, Thomas J. Errico, MD4, John A. Bendo, MD5; 1New York University Hospital for Joint Diseases, New York, NY, US; 2Woodmere, NY, US; 3New York University, New York, NY, US; 4New York University Medical Center, New York, NY, US; 5New York University Hospital for Joint Diseases Spine Center, New York, NY, US BACKGROUND CONTEXT: Degenerative lumbar stenosis (DLS) patients adopt forward-bending posture as a compensatory mechanism, increasing spinal canal and foraminal volume. Previous data show laminectomy 6 short segment fusion results in improvement of sagittal vertical axis (SVA), pelvic tilt (PT) and PI-LL (pelvic incidence-lumbar lordosis) mismatch by SRS-Schwab classification in !25% of patients. The magnitude of deformity for which a DLS patient should have realignment remains unknown. PURPOSE: To identify differences in compensatory mechanisms between DLS and adult spinal deformity (ASD) patients with increasing, and to identify at what point DLS patients recruit ASD-type compensatory mechanisms. STUDY DESIGN/SETTING: Retrospective clinical and radiological review. PATIENT SAMPLE: Baseline X-ray images of 239 patients without spinal instrumentation, with the clinical radiological and diagnosis of DLS or ASD were assessed for patterns of spino-pelvic compensatory mechanisms. Patients were stratified by sagittal vertical axis (SVA) by the Schwab-SRS classification. OUTCOME MEASURES: Radiographic spino-pelvic parameters were measured in the DLS and ASD groups, including SVA, PI-LL, T1SPi, TPA and PT. METHODS: Patients were identified using a single-institution database with sole diagnosis of DLS, O40 years and if they had any of the following: PTO25 , SVAO5cm, thoracic kyphosis (TK)O60 or PI-LL
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.