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Frank J Schwab - One of the best experts on this subject based on the ideXlab platform.
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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, 2014Co-Authors: Themistocles S Protopsaltis, Justin S Smith, Eric O Klineberg, Frank J Schwab, Gregory M Mundis, Nicolas Bronsard, Devon J. Ryan, Richard A. Hostin, Robert Hart, Douglas BurtonAbstract:Background: 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 ( 30°) revealed a significant and progressive worsening in health-related quality of life (p 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
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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
Journal of Bone and Joint Surgery American Volume, 2014Co-Authors: Themistocles S Protopsaltis, Justin S Smith, Eric O Klineberg, Frank J Schwab, Gregory M Mundis, Nicolas Bronsard, Devon J. Ryan, Richard A. Hostin, Robert Hart, Douglas BurtonAbstract:Background: 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 ( 30°) revealed a significant and progressive worsening in health-related quality of life (p 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.
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surgical treatment of pathological loss of lumbar lordosis flatback in patients with normal Sagittal Vertical Axis achieves similar clinical improvement as surgical treatment of elevated Sagittal Vertical Axis clinical article
Journal of Neurosurgery, 2014Co-Authors: Justin S Smith, Virginie Lafage, Manish Singh, Eric O Klineberg, Christopher I Shaffrey, Frank J Schwab, Themistocles S Protopsaltis, David M Ibrahimi, Justin Schee K R, Gregory M MundisAbstract:Object Increased Sagittal Vertical Axis (SVA) correlates strongly with pain and disability for adults with spinal deformity. A subset of patients with Sagittal spinopelvic malalignment (SSM) have flatback deformity (pelvic incidence–lumbar lordosis [PI-LL] mismatch > 10°) but remain Sagittally compensated with normal SVA. Few data exist for SSM patients with flatback deformity and normal SVA. The authors' objective was to compare baseline disability and treatment outcomes for patients with compensated (SVA 10°) and decompensated (SVA > 5 cm) SSM. Methods The study was a multicenter, prospective analysis of adults with spinal deformity who consecutively underwent surgical treatment for SSM. Inclusion criteria included age older than 18 years, presence of adult spinal deformity with SSM, plan for surgical treatment, and minimum 1-year follow-up data. Patients with SSM were divided into 2 groups: those with compensated SSM (SVA 10°) and those with decom...
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assessment of symptomatic rod fracture after posterior instrumented fusion for adult spinal deformity
Neurosurgery, 2012Co-Authors: Justin S Smith, Virginie Lafage, Christopher I Shaffrey, Frank J Schwab, Christopher P Ames, Vedat Deviren, Jason Demakakos, Sassan Keshavarzi, Shay BessAbstract:BACKGROUND: Improved understanding of rod fracture (RF) in adult spinal deformity could be valuable for implant design, surgical planning, and patient counseling. OBJECTIVE: To evaluate symptomatic RF after posterior instrumented fusion for adult spinal deformity. METHODS: A multicenter, retrospective review of RF in adult spinal deformity was performed. Inclusion criteria were spinal deformity, age older than 18 years, and more than 5 levels posterior instrumented fusion. Rod failures were divided into early (#12 months) and late (.12 months). RESULTS: Of 442 patients, 6.8% had symptomatic RF. RF rates were 8.6% for titanium alloy, 7.4% for stainless steel, and 2.7% for cobalt chromium. RF incidence after pedicle subtraction osteotomy (PSO) was 15.8%. Among patients with a PSO and RF, 89% had RF at or adjacent to the PSO. Mean time to early RF (63%) was 6.4 months (range, 2-12 months). Mean time to late RF (37%) was 31.8 months (range, 14-73 months). The majority of RFs after PSO (71%) were early (mean, 10 months). Among RF cases, mean Sagittal Vertical Axis improved from preoperative (163 mm) to postoperative (76.9 mm) measures (P , .001); however, 16 had postoperative malalignment (Sagittal Vertical Axis .50 mm; mean, 109 mm). CONCLUSION: Symptomatic RF occurred in 6.8% of adult spinal deformity cases and in 15.8% of PSO patients. The rate of RF was lower with cobalt chromium than with titanium alloy or stainless steel. Early failure was most common after PSO and favored the PSO site, suggesting that RF may be caused by stress at the PSO site. Postoperative Sagittal malalignment may increase the risk of RF.
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impact of spinopelvic alignment on decision making in deformity surgery in adults a review
Journal of Neurosurgery, 2012Co-Authors: Christopher P Ames, Virginie Lafage, Justin S Smith, Frank J Schwab, Vedat Deviren, Shay Bess, Justin K Scheer, Samuel S Bederman, Christopher I ShaffreyAbstract:Sagittal spinal misalignment (SSM) is an established cause of pain and disability. Treating physicians must be familiar with the radiographic findings consistent with SSM. Additionally, the restoration or maintenance of physiological Sagittal spinal alignment after reconstructive spinal procedures is imperative to achieve good clinical outcomes. The C-7 plumb line (Sagittal Vertical Axis) has traditionally been used to evaluate Sagittal spinal alignment; however, recent data indicate that the measurement of spinopelvic parameters provides a more comprehensive assessment of Sagittal spinal alignment. In this review the authors describe the proper analysis of spinopelvic alignment for surgical planning. Online videos supplement the text to better illustrate the key concepts.
Justin S Smith - One of the best experts on this subject based on the ideXlab platform.
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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
Journal of Bone and Joint Surgery American Volume, 2014Co-Authors: Themistocles S Protopsaltis, Justin S Smith, Eric O Klineberg, Frank J Schwab, Gregory M Mundis, Nicolas Bronsard, Devon J. Ryan, Richard A. Hostin, Robert Hart, Douglas BurtonAbstract:Background: 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 ( 30°) revealed a significant and progressive worsening in health-related quality of life (p 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.
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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, 2014Co-Authors: Themistocles S Protopsaltis, Justin S Smith, Eric O Klineberg, Frank J Schwab, Gregory M Mundis, Nicolas Bronsard, Devon J. Ryan, Richard A. Hostin, Robert Hart, Douglas BurtonAbstract:Background: 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 ( 30°) revealed a significant and progressive worsening in health-related quality of life (p 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
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surgical treatment of pathological loss of lumbar lordosis flatback in patients with normal Sagittal Vertical Axis achieves similar clinical improvement as surgical treatment of elevated Sagittal Vertical Axis clinical article
Journal of Neurosurgery, 2014Co-Authors: Justin S Smith, Virginie Lafage, Manish Singh, Eric O Klineberg, Christopher I Shaffrey, Frank J Schwab, Themistocles S Protopsaltis, David M Ibrahimi, Justin Schee K R, Gregory M MundisAbstract:Object Increased Sagittal Vertical Axis (SVA) correlates strongly with pain and disability for adults with spinal deformity. A subset of patients with Sagittal spinopelvic malalignment (SSM) have flatback deformity (pelvic incidence–lumbar lordosis [PI-LL] mismatch > 10°) but remain Sagittally compensated with normal SVA. Few data exist for SSM patients with flatback deformity and normal SVA. The authors' objective was to compare baseline disability and treatment outcomes for patients with compensated (SVA 10°) and decompensated (SVA > 5 cm) SSM. Methods The study was a multicenter, prospective analysis of adults with spinal deformity who consecutively underwent surgical treatment for SSM. Inclusion criteria included age older than 18 years, presence of adult spinal deformity with SSM, plan for surgical treatment, and minimum 1-year follow-up data. Patients with SSM were divided into 2 groups: those with compensated SSM (SVA 10°) and those with decom...
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assessment of symptomatic rod fracture after posterior instrumented fusion for adult spinal deformity
Neurosurgery, 2012Co-Authors: Justin S Smith, Virginie Lafage, Christopher I Shaffrey, Frank J Schwab, Christopher P Ames, Vedat Deviren, Jason Demakakos, Sassan Keshavarzi, Shay BessAbstract:BACKGROUND: Improved understanding of rod fracture (RF) in adult spinal deformity could be valuable for implant design, surgical planning, and patient counseling. OBJECTIVE: To evaluate symptomatic RF after posterior instrumented fusion for adult spinal deformity. METHODS: A multicenter, retrospective review of RF in adult spinal deformity was performed. Inclusion criteria were spinal deformity, age older than 18 years, and more than 5 levels posterior instrumented fusion. Rod failures were divided into early (#12 months) and late (.12 months). RESULTS: Of 442 patients, 6.8% had symptomatic RF. RF rates were 8.6% for titanium alloy, 7.4% for stainless steel, and 2.7% for cobalt chromium. RF incidence after pedicle subtraction osteotomy (PSO) was 15.8%. Among patients with a PSO and RF, 89% had RF at or adjacent to the PSO. Mean time to early RF (63%) was 6.4 months (range, 2-12 months). Mean time to late RF (37%) was 31.8 months (range, 14-73 months). The majority of RFs after PSO (71%) were early (mean, 10 months). Among RF cases, mean Sagittal Vertical Axis improved from preoperative (163 mm) to postoperative (76.9 mm) measures (P , .001); however, 16 had postoperative malalignment (Sagittal Vertical Axis .50 mm; mean, 109 mm). CONCLUSION: Symptomatic RF occurred in 6.8% of adult spinal deformity cases and in 15.8% of PSO patients. The rate of RF was lower with cobalt chromium than with titanium alloy or stainless steel. Early failure was most common after PSO and favored the PSO site, suggesting that RF may be caused by stress at the PSO site. Postoperative Sagittal malalignment may increase the risk of RF.
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impact of spinopelvic alignment on decision making in deformity surgery in adults a review
Journal of Neurosurgery, 2012Co-Authors: Christopher P Ames, Virginie Lafage, Justin S Smith, Frank J Schwab, Vedat Deviren, Shay Bess, Justin K Scheer, Samuel S Bederman, Christopher I ShaffreyAbstract:Sagittal spinal misalignment (SSM) is an established cause of pain and disability. Treating physicians must be familiar with the radiographic findings consistent with SSM. Additionally, the restoration or maintenance of physiological Sagittal spinal alignment after reconstructive spinal procedures is imperative to achieve good clinical outcomes. The C-7 plumb line (Sagittal Vertical Axis) has traditionally been used to evaluate Sagittal spinal alignment; however, recent data indicate that the measurement of spinopelvic parameters provides a more comprehensive assessment of Sagittal spinal alignment. In this review the authors describe the proper analysis of spinopelvic alignment for surgical planning. Online videos supplement the text to better illustrate the key concepts.
Virginie Lafage - One of the best experts on this subject based on the ideXlab platform.
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Relationship between body mass index and Sagittal Vertical Axis change as well as health-related quality of life in 564 patients after deformity surgery: Presented at the 2019 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves
Journal of neurosurgery. Spine, 2019Co-Authors: Nitin Agarwal, Virginie Lafage, Themistocles S Protopsaltis, Ezequiel Goldschmidt, Federico Angriman, James Zhou, Adam S. Kanter, David O. Okonkwo, Peter G. Passias, Renaud LafageAbstract:OBJECTIVE Obesity, a condition that is increasing in prevalence in the United States, has previously been associated with poorer outcomes following deformity surgery, including higher rates of perioperative complications such as deep and superficial infections. To date, however, no study has examined the relationship between preoperative BMI and outcomes of deformity surgery as measured by spine parameters such as the Sagittal Vertical Axis (SVA), as well as health-related quality of life (HRQoL) measures such as the Oswestry Disability Index (ODI) and Scoliosis Research Society-22 patient questionnaire (SRS-22). To this end, the authors sought to clarify the relationship between BMI and postoperative change in SVA as well as HRQoL outcomes. METHODS The authors performed a retrospective review of a prospectively managed multicenter adult spinal deformity database collected and maintained by the International Spine Study Group (ISSG) between 2009 and 2014. The primary independent variable considered was preoperative BMI. The primary outcome was the change in SVA at 1 year after deformity surgery. Postoperative ODI and SRS-22 outcome measures were evaluated as secondary outcomes. Generalized linear models were used to model the primary and secondary outcomes at 1 year as a function of BMI at baseline, while adjusting for potential measured confounders. RESULTS Increasing BMI (compared to BMI 30 appeared to be associated with poorer outcomes as determined by the ODI, this correlation did not reach statistical significance. CONCLUSIONS Baseline BMI did not affect the achievable SVA at 1 year postsurgery. Further studies should evaluate whether even in the absence of a change in SVA, baseline BMIs in the obese range are associated with worsened HRQoL outcomes after spinal surgery.
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Variation of the Sagittal Vertical Axis during walking and its determinants
Gait & Posture, 2018Co-Authors: Ayman Assi, Ziad Bakouny, Aren Joe Bizdikian, Joeffroy Otayek, Fares Yared, Virginie Lafage, Nour Khalil, Abir Massaad, Ismat Ghanem, Wafa SkalliAbstract:Patients with adult spinal deformities (ASD) are known to have altered postural alignment affecting their quality of life and activities of daily living, especially gait. The Sagittal Vertical Axis (SVA), a postural parameter calculated as the distance between the posterior corner of the sacrum and the C7-plumbline on full-body Sagittal radiographs [1], has been shown to be highly altered in ASD. Even though this parameter is positional and could vary during gait, no studies have investigated its variation during walking even in asymptomatic subjects.
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Does Minimally Invasive Percutaneous Posterior Instrumentation Reduce Risk of Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery? A Propensity-Matched Cohort Analysis.
Neurosurgery, 2015Co-Authors: Praveen V Mummaneni, Virginie Lafage, Paul Park, Michael Y. Wang, Stacie Nguyen, Juan S. Uribe, John E. Ziewacz, Jamie S. Terran, David O. OkonkwoAbstract:BACKGROUND Proximal junctional kyphosis (PJK) is a known complication after spinal deformity surgery. One potential cause is disruption of posterior muscular tension band during pedicle screw placement. OBJECTIVE To investigate the effect of minimally invasive surgery (MIS) on PJK. METHODS A multicenter database of patients who underwent deformity surgery was propensity matched for pelvic incidence (PI) to lumbar lordosis (LL) mismatch and change in LL. Radiographic PJK was defined as proximal junctional angle >10°. Sixty-eight patients made up the circumferential MIS (cMIS) group, and 68 were in the hybrid (HYB) surgery group (open screw placement). RESULTS Preoperatively, there was no difference in age, body mass index, PI-LL mismatch, or Sagittal Vertical Axis. The mean number of levels treated posteriorly was 4.7 for cMIS and 8.2 for HYB (P < .001). Both had improved LL and PI-LL mismatch postoperatively. Sagittal Vertical Axis remained physiological for the cMIS and HYB groups. Oswestry Disability Index scores were significantly improved in both groups. Radiographic PJK developed in 31.3% of the cMIS and 52.9% of the HYB group (P = .01). Reoperation for PJK was 4.5% for the cMIS and 10.3% for the HYB group (P = .20). Subgroup analysis for patients undergoing similar levels of posterior instrumentation in the cMIS and HYB groups found a PJK rate of 48.1% and 53.8% (P = .68) and a reoperation rate of 11.1% and 19.2%, respectively (P = .41). Mean follow-up was 32.8 months. CONCLUSION Overall rates of radiographic PJK and reoperation for PJK were not significantly decreased with MIS pedicle screw placement. However, a larger comparative study is needed to confirm that MIS pedicle screw placement does not affect PJK.
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surgical treatment of pathological loss of lumbar lordosis flatback in patients with normal Sagittal Vertical Axis achieves similar clinical improvement as surgical treatment of elevated Sagittal Vertical Axis clinical article
Journal of Neurosurgery, 2014Co-Authors: Justin S Smith, Virginie Lafage, Manish Singh, Eric O Klineberg, Christopher I Shaffrey, Frank J Schwab, Themistocles S Protopsaltis, David M Ibrahimi, Justin Schee K R, Gregory M MundisAbstract:Object Increased Sagittal Vertical Axis (SVA) correlates strongly with pain and disability for adults with spinal deformity. A subset of patients with Sagittal spinopelvic malalignment (SSM) have flatback deformity (pelvic incidence–lumbar lordosis [PI-LL] mismatch > 10°) but remain Sagittally compensated with normal SVA. Few data exist for SSM patients with flatback deformity and normal SVA. The authors' objective was to compare baseline disability and treatment outcomes for patients with compensated (SVA 10°) and decompensated (SVA > 5 cm) SSM. Methods The study was a multicenter, prospective analysis of adults with spinal deformity who consecutively underwent surgical treatment for SSM. Inclusion criteria included age older than 18 years, presence of adult spinal deformity with SSM, plan for surgical treatment, and minimum 1-year follow-up data. Patients with SSM were divided into 2 groups: those with compensated SSM (SVA 10°) and those with decom...
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assessment of symptomatic rod fracture after posterior instrumented fusion for adult spinal deformity
Neurosurgery, 2012Co-Authors: Justin S Smith, Virginie Lafage, Christopher I Shaffrey, Frank J Schwab, Christopher P Ames, Vedat Deviren, Jason Demakakos, Sassan Keshavarzi, Shay BessAbstract:BACKGROUND: Improved understanding of rod fracture (RF) in adult spinal deformity could be valuable for implant design, surgical planning, and patient counseling. OBJECTIVE: To evaluate symptomatic RF after posterior instrumented fusion for adult spinal deformity. METHODS: A multicenter, retrospective review of RF in adult spinal deformity was performed. Inclusion criteria were spinal deformity, age older than 18 years, and more than 5 levels posterior instrumented fusion. Rod failures were divided into early (#12 months) and late (.12 months). RESULTS: Of 442 patients, 6.8% had symptomatic RF. RF rates were 8.6% for titanium alloy, 7.4% for stainless steel, and 2.7% for cobalt chromium. RF incidence after pedicle subtraction osteotomy (PSO) was 15.8%. Among patients with a PSO and RF, 89% had RF at or adjacent to the PSO. Mean time to early RF (63%) was 6.4 months (range, 2-12 months). Mean time to late RF (37%) was 31.8 months (range, 14-73 months). The majority of RFs after PSO (71%) were early (mean, 10 months). Among RF cases, mean Sagittal Vertical Axis improved from preoperative (163 mm) to postoperative (76.9 mm) measures (P , .001); however, 16 had postoperative malalignment (Sagittal Vertical Axis .50 mm; mean, 109 mm). CONCLUSION: Symptomatic RF occurred in 6.8% of adult spinal deformity cases and in 15.8% of PSO patients. The rate of RF was lower with cobalt chromium than with titanium alloy or stainless steel. Early failure was most common after PSO and favored the PSO site, suggesting that RF may be caused by stress at the PSO site. Postoperative Sagittal malalignment may increase the risk of RF.
Praveen V Mummaneni - One of the best experts on this subject based on the ideXlab platform.
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The effect of anterior cervical discectomy and fusion (ACDF) on cervical Sagittal Vertical Axis and lordosis with minimum 2-year follow up.
World neurosurgery, 2021Co-Authors: Rong Xie, Jinping Liu, Minghao Wang, Yinhui Dong, Praveen V Mummaneni, Dean ChouAbstract:Anterior cervical discectomy and fusion (ACDF) can induce lordosis and improve cervical Sagittal Vertical Axis (cSVA), but multi-level ACDF may inadvertently increase cSVA because of insufficient lordosis induction. Patients who underwent 1, 2, or ≥3-level ACDFs in the subaxial spine with minimum 2-year follow up (f/u) at the University of California San Francisco were retrospectively studied. Exclusion criteria were trauma, infection, tumor, arthroplasty, stand-alone cages, previous anterior fusion, or concomitant posterior cervical fusion. The C2-7 Cobb (lordosis), cSVA, and T1 slope were measured pre-operatively, immediately post-operatively, and at last f/u. A total of 127 patients met inclusion criteria. There were no differences in baseline demographics among 1, 2, and ≥3-level ACDF groups. Mean f/u was 43.7 (24-142) months. Increase of post-operative cSVA immediately post-operative was 1.94mm, -1.44mm, and 7.25mm for 1, 2, and ≥3-level ACDF, respectively (p=0.041), and 2.97mm, 0.70mm, and 9.32mm for 1, 2, and ≥3-level ACDF respectively at last f/u (p=0.026). Two-level ACDF patients had the greatest decrease in T1 slope (-0.43°) compared to an increase of 2.71° for 1-level and 2.84° for ≥3-level (p=0.028) at last f/u. Segmental (ACDF levels) lordosis, cSVA and T1 slope did not decrease from immediate postop to last f/u in all three groups. However, only 2-level ACDF maintained C2-7 lordosis (2.16°) compared to loss of lordosis in one (-0.84°) and ≥3-level (-2.00°) (p=0.008) at last f/u. Linear regression analysis showed that the T1 slope had no relationship with correction of cSVA (p=0.5310), but had a significant correlation with Cobb angle loss of C2-7 lordosis (p=0.0016). ≥3-level ACDF resulted in significant increase of cSVA and loss of overall lordosis compared to 1- and 2-level ACDF. 2-level ACDF had the greatest ability to maintain the lordosis compared to 1- and ≥3-level ACDF. T1 slope had a significant correlation with loss of C2-7 lordosis after ACDF. Copyright © 2021 Elsevier Inc. All rights reserved.
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Applicability of cervical Sagittal Vertical Axis, cervical lordosis, and T1 slope on pain and disability outcomes after anterior cervical discectomy and fusion in patients without deformity
Journal of neurosurgery. Spine, 2019Co-Authors: Darryl Lau, Dean Chou, Anthony M. Digiorgio, Andrew K. Chan, Cecilia L. Dalle Ore, Michael S. Virk, Erica F. Bisson, Praveen V MummaneniAbstract:OBJECTIVE Understanding what influences pain and disability following anterior cervical discectomy and fusion (ACDF) in patients with degenerative cervical spine disease is critical. This study examines the timing of clinical improvement and identifies factors (including spinal alignment) associated with worse outcomes. METHODS Consecutive adult patients were enrolled in a prospective outcomes database from two academic centers participating in the Quality Outcomes Database from 2013 to 2016. Demographics, surgical details, radiographic data, arm and neck pain (visual analog scale [VAS] scores), and disability (Neck Disability Index [NDI] and EQ-5D scores) were reviewed. Multivariate analysis was used. RESULTS A total of 186 patients were included, and 48.4% were male. Their mean age was 55.4 years, and 45.7% had myelopathy. Preoperative cervical Sagittal Vertical Axis (cSVA), cervical lordosis (CL), and T1 slope values were 24.9 mm (range 0-55 mm), 10.4° (range -6.0° to 44°), and 28.3° (range 14.0°-51.0°), respectively. ACDF was performed at 1, 2, and 3 levels in 47.8%, 42.0%, and 10.2% of patients, respectively. Preoperative neck and arm VAS scores were 5.7 and 5.4, respectively. NDI and EQ-5D scores were 22.1 and 0.5, respectively. There was significant improvement in all outcomes at 3 months (p < 0.001) and 12 months (p < 0.001). At 3 months, neck VAS (3.0), arm VAS (2.2), NDI (12.7), and EQ-5D (0.7) scores were improved, and at 12 months, neck VAS (2.8), arm VAS (2.3), NDI (11.7), and EQ-5D (0.8) score improvements were sustained. Improvements occurred within the first 3-month period; there was no significant difference in outcomes between the 3-month and 12-month mark. There was no correlation among cSVA, CL, or T1 slope with any outcome endpoint. The most consistent independent preoperative factors associated with worse outcomes were high neck and arm VAS scores and a severe NDI result (p < 0.001). Similar findings were seen with worse NDI and EQ-5D scores (p < 0.001). A significant linear trend of worse NDI and EQ-5D scores at 3 and 12 months was associated with worse baseline scores. Of the 186 patients, 171 (91.9%) had 3-month follow-up data, and 162 (87.1%) had 12-month follow-up data. CONCLUSIONS ACDF is effective in improving pain and disability, and improvement occurs within 3 months of surgery. cSVA, CL, and T1 slope do not appear to influence outcomes following ACDF surgery in the population with degenerative cervical disease. Therefore, in patients with relatively normal cervical parameters, augmenting alignment or lordosis is likely unnecessary. Worse preoperative pain and disability were independently associated with worse outcomes.
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Comparing Radiographic Parameters for Single-Level L5-S1 Interbody Fusion: Anterior Lumbar (ALIF) Versus Transforaminal Lumbar Interbody Fusion (TLIF)
Neurosurgery, 2019Co-Authors: Caleb S. Edwards, Andrew K. Chan, Dean Chou, Praveen V MummaneniAbstract:Abstract INTRODUCTION The lumbosacral junction acts as a transition point between the mobile lumbar spine and the rigid pelvis. It is thereby susceptible to degenerative changes necessitating fusion at L5-S1. In this study, we compared radiographic outcomes observed from single-level anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) at this level. METHODS Retrospective review of single-level ALIF and TLIF with up to one level PSF at L5-S1 between May 2007 and October 2018 was undertaken. X-ray measurements were gathered for lumbar lordosis, segmental lordosis, pelvic tilt, sacral slope, pelvic incidence, pelvic incidence-lumbar lordosis mismatch, anterior/posterior disc height, and Sagittal Vertical Axis. Computed tomography /magnetic resonance imaging was used to determine central canal area, Sagittal diameter, foraminal height, and foraminal area. RESULTS A total of 47 ALIF patients and 50 TLIF patients were included. Patients averaged 53.7 ± 10.1 yr of age for ALIF and 49.4 ± 14.7 yr old for TLIF (P = .094) with significant differences (P = .0017) seen with gender as ALIF had 60.4% males and TLIF 70.0% females. Single-level ALIF led to significantly (P = .0010) more segmental lordosis (+5.75° ± 7.31°) than TLIF (+0.25° ± 6.55°), though differences in lumbar lordosis were not statistically significant (P = .52). ALIF significantly increased both anterior (+10.4 ± 4.32 mm vs +4.30 ± 3.55 mm; P < .0001) and posterior disc height (+4.33 ± 3.32 mm vs + 2.98 ± 2.07 mm; P = .043) than TLIF. Changes in Sagittal Vertical Axis also significantly differed (P = .030) with ALIF decreasing Sagittal Vertical Axis by 17.8 ± 26.4 mm from +60.3 mm to + 42.5 mm, and TLIF increasing by 0.95 ± 25.8 mm from 39.9 mm to 40.9 mm. Pelvic tilt, sacral slope, pelvic incidence, pelvic incidence-lumbar lordosis mismatch had no significant differences. No statistically significant differences were observed with central canal area, Sagittal diameter, foraminal height or foraminal area between ALIF and TLIF. CONCLUSION At L5-S1, the ALIF approach leads to increased segmental lordosis, disc height, while also decreasing Sagittal Vertical Axis to a significant degree than TLIF. However, these two approaches were no different with regards to pelvic parameters and measures of central canal and foraminal decompression.
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Evolution of the Minimally Invasive Spinal Deformity Surgery Algorithm: An Evidence-Based Approach to Surgical Strategies for Deformity Correction.
Neurosurgery clinics of North America, 2018Co-Authors: Winward Choy, Paul Park, Andrew K. Chan, Catherine Miller, Praveen V MummaneniAbstract:Minimally invasive surgery (MIS) is an alternative to open surgery for adult spinal deformity correction. However, not all patients are ideal candidates for MIS correction. The minimally invasive spinal deformity surgery algorithm is a systematic and reproducible decision-making framework for surgeons to identify patients appropriate for deformity correction by MIS techniques. Key spinopelvic parameters including Sagittal Vertical Axis, pelvic tilt, pelvic incidence to lumbar lordosis mismatch, and coronal Cobb angle are used to guide surgeons toward three treatment classes ranging from MIS to traditional open approaches. This article updates the minimally invasive spinal deformity surgery algorithm and presents representative cases.
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Does Minimally Invasive Percutaneous Posterior Instrumentation Reduce Risk of Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery? A Propensity-Matched Cohort Analysis.
Neurosurgery, 2015Co-Authors: Praveen V Mummaneni, Virginie Lafage, Paul Park, Michael Y. Wang, Stacie Nguyen, Juan S. Uribe, John E. Ziewacz, Jamie S. Terran, David O. OkonkwoAbstract:BACKGROUND Proximal junctional kyphosis (PJK) is a known complication after spinal deformity surgery. One potential cause is disruption of posterior muscular tension band during pedicle screw placement. OBJECTIVE To investigate the effect of minimally invasive surgery (MIS) on PJK. METHODS A multicenter database of patients who underwent deformity surgery was propensity matched for pelvic incidence (PI) to lumbar lordosis (LL) mismatch and change in LL. Radiographic PJK was defined as proximal junctional angle >10°. Sixty-eight patients made up the circumferential MIS (cMIS) group, and 68 were in the hybrid (HYB) surgery group (open screw placement). RESULTS Preoperatively, there was no difference in age, body mass index, PI-LL mismatch, or Sagittal Vertical Axis. The mean number of levels treated posteriorly was 4.7 for cMIS and 8.2 for HYB (P < .001). Both had improved LL and PI-LL mismatch postoperatively. Sagittal Vertical Axis remained physiological for the cMIS and HYB groups. Oswestry Disability Index scores were significantly improved in both groups. Radiographic PJK developed in 31.3% of the cMIS and 52.9% of the HYB group (P = .01). Reoperation for PJK was 4.5% for the cMIS and 10.3% for the HYB group (P = .20). Subgroup analysis for patients undergoing similar levels of posterior instrumentation in the cMIS and HYB groups found a PJK rate of 48.1% and 53.8% (P = .68) and a reoperation rate of 11.1% and 19.2%, respectively (P = .41). Mean follow-up was 32.8 months. CONCLUSION Overall rates of radiographic PJK and reoperation for PJK were not significantly decreased with MIS pedicle screw placement. However, a larger comparative study is needed to confirm that MIS pedicle screw placement does not affect PJK.
G. Alexander Jones - One of the best experts on this subject based on the ideXlab platform.
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Neutral cervical Sagittal Vertical Axis and cervical lordosis vary with T1 tilt
Journal of neurosurgery. Spine, 2020Co-Authors: Ryan C. Hofler, Muturi Muriuki, Robert M. Havey, Kenneth R. Blank, Joseph N. Frazzetta, Avinash G. Patwardhan, G. Alexander JonesAbstract:OBJECTIVE The authors conducted a study to determine whether a change in T1 tilt results in a compensatory change in the cervical Sagittal Vertical Axis (SVA) in a cadaveric spine model. METHODS Six fresh-frozen cadavers (occiput [C0]-T1) were cleaned of soft tissue and mounted on a customized test apparatus. A 5-kg mass was applied to simulate head weight. Infrared fiducials were used to track segmental motion. The occiput was constrained to maintain horizontal gaze, and the mounting platform was angled to change T1 tilt. The SVA was altered by translating the upper (occipital) platform in the anterior-posterior plane. Neutral SVA was defined by the lowest flexion-extension moment at T1 and recorded for each T1 tilt. Lordosis was measured at C0-C2, C2-7, and C0-C7. RESULTS Neutral SVA was positively correlated with T1 tilt in all specimens. After increasing T1 tilt by a mean of 8.3° ± 2.2°, neutral SVA increased by 27.3 ± 18.6 mm. When T1 tilt was reduced by 6.7° ± 1.4°, neutral SVA decreased by a mean of 26.1 ± 17.6 mm.When T1 tilt was increased, overall (C0-C7) lordosis at the neutral SVA increased from 23.1° ± 2.6° to 32.2° ± 4.4° (p < 0.01). When the T1 tilt decreased, C0-C7 lordosis at the neutral SVA decreased to 15.6° ± 3.1° (p < 0.01). C0-C2 lordosis increased from 12.9° ± 9.3° to 29.1° ± 5.0° with increased T1 tilt and decreased to -4.3° ± 6.8° with decreased T1 tilt (p = 0.047 and p = 0.041, respectively). CONCLUSIONS Neutral SVA is not a fixed property but, rather, is positively correlated with T1 tilt in all specimens. Overall lordosis and C0-C2 lordosis increased when T1 tilt was increased from baseline, and vice versa.
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135. Neutral cervical Sagittal Vertical Axis (SVA) varies with T1 tilt
The Spine Journal, 2019Co-Authors: Ryan C. Hofler, Muturi Muriuki, Robert M. Havey, Kenneth R. Blank, Avinash G. Patwardhan, G. Alexander JonesAbstract:BACKGROUND CONTEXT With an aging population and increasing incidence of cervical spine surgery, more attention is being focused on cervical alignment and deformity. Iatrogenic deformity can result from under- or overcorrection of cervical Sagittal alignment during fusion surgery. We sought to explore the relationship between T1 tilt and cervical SVA. In our cadaveric study, the Sagittal Vertical alignment (SVA) was altered for a given T1 tilt until the least extrinsic force was required to maintain alignment. This correlates with the in vivo state requiring the least muscle contraction to maintain alignment. PURPOSE To determine if an increase or decrease in T1 tilt from baseline will require a compensatory increase or decrease in SVA in order to maintain neutral posture. STUDY DESIGN/SETTING Cadaver biomechanical study. PATIENT SAMPLE Six cadaveric cervical spines (occiput-T1). OUTCOME MEASURES C0-T1 SVA (mm). METHODS Six cadaveric cervical spines (occiput-T1) were mounted with a 5 kg mass simulating head weight. Forces and moments were recorded with a load cell. Motion was recorded with optoelectric sensors placed at each level, and a thin cut CT was used to create a 3-dimensional reconstruction. The head was constrained to maintain horizontal gaze. T1 tilt and SVA were adjusted by rotating or translating the test bed (respectively) to find the condition requiring the least extrinsic force to maintain. T1 tilt was then decreased, and SVA was adjusted to minimize extrinsic force and measured. T1 tilt was then increased and SVA adjusted and measured. RESULTS T1 tilt was decreased an average of 6.49 ± 1.39° (mean ± SD) from baseline, requiring a decrease in C0-T1 SVA of 28.14 ± 17.41 mm to achieve neutral posture. T1 tilt was increased 35.12 ± 37.08° from baseline, leading to an increase in SVA of 8.80 ± 2.72 mm. CONCLUSIONS As T1 tilt was increased from baseline, an increase in C0-T1 SVA was required to maintain neutral posture. As T1 tilt was decreased, a decrease in SVA was required. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.
