Faculty Bibliography

BACKGROUND CONTEXT: The Adult Spinal Deformity Invasiveness Index incorporates deformity-specific components to assess the magnitude of correction. It's unknown how invasiveness relates to outcomes in each frailty state. PURPOSE: Investigate the relationship between increasing invasiveness and outcomes in ASD surgery in each frailty states. STUDY DESIGN/SETTING: Retrospective review of prospective, consecutively enrolled multicenter ASD database. PATIENT SAMPLE: A total of 195 ASD patients with baseline demographic and surgical details. OUTCOME MEASURES: Invasiveness, frailty, minimal clinically important differences (MCID) for the Oswestry Disability Index, SF-36 Physical Component Scores, and Scoliosis Research Society Scores.
METHOD(S): ASD patients (scoliosis >=20degree, SVA >=5cm, PT >=25degree, or TK >=60degree) with baseline frailty and invasiveness scores. Invasiveness index included; posterior: decompression (1), fusion (2), instrumentation (1), osteotomies: 3-coloumn (14), Ponte (1), interbody fusion; anterior lumbar (8), transforaminal/posterior lumbar (2), iliac fixation (2), revision surgery (3). Invasiveness scores were calculated within different frailty states (not frail, NF, <0.3), frail (F, 0.3-0.5), severely frail (SF, >0.5). Logistic regression analysis assessed the relationship between increasing invasiveness and major complications or reoperations and meeting MCID for any of the measured HRQLs at 3 years. Decision tree analysis assessed thresholds for an invasiveness risk benefit cutoff point, above which experiencing complications or reoperations and not reaching MCID were higher. Significance was set to p<0.05.
RESULT(S): One hundred ninety-five of 322 patients met inclusion criteria. Baseline demographic info: age 59.9 +/- 14.4, 75% female, BMI 27.8 +/- 6.2, CCI 1.7 +/- 1.7. Baseline surgical info: 61% osteotomy, 52% decompression, 11.0 +/- 4.1 levels fused. There were 98 NF, 65 F, and 30 SF patients. For the entire cohort, binary regression analysis found a significant relationship between increasing invasiveness and experiencing a major complication or reoperation (1.01 [1.00-1.02], p=0.01). Within each frailty subgroup, the results were 1.01 ([1.00-1.03], p=0.05) for NF, 1.01 ([1.01-1.02], p<0.001) for F, and 1.01 ([1.00-1.01], p=0.02) for SF. When defining no major complications or reoperation and meeting MCID in any HRQL at 3 years as a favorable outcome, decision tree analysis established an invasiveness risk benefit cutoff of 63.9. Patients below this threshold were 1.8 [1.38-2.35] (p<0.001) times more likely to not have a major complication/reoperation and meet MCID at 3 years. Invasiveness above this point was a negative predictor (0.55 [0.401-0.754], p<0.001). When factoring in frailty, for NF patients the risk benefit cutoff was 79.3 (2.11 [1.39-3.20] (p<0.001), 111 for F (2.62 [1.70-4.06] (p<0.001), and 53.3 for SF (2.35 [0.78-7.13] (p=0.13).
CONCLUSION(S): Increasing invasiveness is associated with increased odds of major complications and reoperations. A risk/benefit cutoff for decreasing major complications/reoperations and meeting MCID was found to be 79.3 for NF patients, 111 for F patients, and 53.3 for SF patients. Above these thresholds, increasing invasiveness is associated with increasing the risk of major complications or reoperations and not meeting MCID at 3 years. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Spinal and body balance are active processes requiring a thorough understanding of the harmony between static posture and dynamic motion. Our understanding of patients' function is lacking a more objective and quantified mechanism of assessment. The Dubousset Functional Test (DFT) is a four-component, novel, multidomain physical function and balance assessment proposed by Dr. Jean Dubousset. PURPOSE: To identify normative baseline/reference values for DFT in asymptomatic, healthy subjects, establish test feasibility, and identify correlations between demographics and DFT performance in the general population. STUDY DESIGN/SETTING: Prospective single-center. PATIENT SAMPLE: Sixty-five asymptomatic volunteers (mean age: 42.4+/-15.4 years; 42% female, mean BMI 26+/-4.8kg/m2). OUTCOME MEASURES: Demographics, DFT components: Up-and-Walking Test (UWT), Steps Test (ST), Down-and-Sitting Test (DST), Dual-Tasking Test (DTT).
METHOD(S): Asymptomatic volunteers were screened and recruited to participate in the 4 DFT components at a single center from 2017-2018. These include: (1) UWT (Up-and-Walking Test): unassisted sit-to-stand, walk forward/backward 5 m (no turn), unassisted sit; (2) ST (Steps Test): ascend 3 steps, turn, descend 3 steps; (3) DST (Down-and-Sitting Test): stand-to-ground sit-to-stand, assistance as needed; (4) DTT (Dual-Tasking Test): walk 5 m forth and back while counting down from 50 by 2. All subjects were given standardized verbal instructions and a physical demonstration for each DFT test. Trials were video recorded and timed, with scores assigned by time required to complete the test. All trials were conducted and all tests were scored by the same rater. Univariate and multivariate analysis were utilized to analyze durations of test components against demographics.
RESULT(S): 65 subjects were included (mean age, 42.4+/-15.4 years); 42% were female, and mean BMI was 26+/-4.8 kg/m^2. The racial breakdown of the cohort was 34% White, 25% Black, 15% Asian, 9% Indian, 6% Latino, 10% other. Evaluating the four components of the DFT, the mean and standard deviations of each test component were as follows: mean duration in seconds and 95% confidence interval of each DFT test: UWT: 14.8s (14.0-15.6s), ST: 6.3s (6.0-6.6s), DST: 6.0s (5.4-6.6s), and DTT: 12.8s (12.1-13.6s). There were no differences between males and females in time taken to perform any of the tests. There were significant correlations between age and DST (r=0.529), UWT (r=0.429), and ST (r=0.356) (all p<0.05), with no correlation found with DTT. A similar trend was found with respect to correlation with BMI (r=0.372, r=0.289, and r=0.366, p<0.05), with no correlation again found with DTT. With respect to DTT specifically, patients on average finished countdown from 50 to 29.7+/-5.3. 12.3% of subjects exhibited physical pausing during the DTT, and 87.5% of those were pauses occurred while turning. Among total subjects, 32.3% exhibited verbal pausing/stuttering/mistakes in counting during the Dual Tasking test; of these, 62% occurred while turning.
CONCLUSION(S): The DFT is a quick and feasible test that was performed safely in a cohort of healthy subjects. Age and BMI, but not gender, were found to influence all DFT tests. Physical and verbal pausing were reported in about 1/10 and 1/3 patients, respectively, with the majority of pausing occurring during the turning phase of the test. Utilization of this test in patients with spinal pathologies may help us to determine the offset from norms as well as understand the impact of preoperative DFT performance on surgical outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Sagittal malalignment has been discussed extensively in adult spinal deformity (ASD) literature, while coronal malalignment (CM) and fractional curve (FC) have received less attention. As a result, little guidance currently exists for surgical indications in managing CM, despite it being a relatively common occurrence that can considerably impact patient wellbeing. Patients with CM significantly affected by FC are at particular risk for continued CM postoperatively, along with its complications. PURPOSE: Assess types of approach to fusion of the fractional curve in ASD surgery and their relation to coronal alignment and sagittal alignment. STUDY DESIGN/SETTING: Retrospective review at single institution. PATIENT SAMPLE: A total of 82 ASD patients undergoing primary spinal fusion of 4 or more levels to sacrum or pelvis. OUTCOME MEASURES: Baseline (BL), 1-year (Y1) postoperatively and BL-Y1 difference (DELTABL-Y1) in magnitudes of FC, coronal alignment (CA) and sagittal alignment (SA) parameters: pelvic incidence-LL (PI-LL), cervical sagittal vertical axis (cSVA), T1 pelvic angle (TPA).
METHOD(S): Patients >=18 years old undergoing primary >=4-level fusion to sacrum/pelvis between October 2011 and January 2018 with minimum 6-month follow-up included. Chart review performed for operative dates and details and patient follow-up information. Coronal and sagittal parameters measured using deformity measuring software program. FC measured as segmental angle between L4 and S1. CA measured as distance between C7 plumb line and central sacral vertical line. CA>=20mm designated as CM, per guidelines in literature. Chi-squared test used to compare percentages and ANOVA used to compare means, with significance set at p<0.05.
RESULT(S): A total of 82 patients studied (68.3%F, age 62.6+/-13.3, BMI 28.1+/-6.6, Charlson comorbidity index 0.80+/-1.16). Nine patients (10.98%) had anterior-posterior fusion (AP), 41 (50%) posterior-only fusion with interbody device (PIB), 32 (39.02%) PSF without interbody (PSF). Twenty-three patients (28.04%) had FC>=15degree at BL, 7 (8.54%) at Y1. Forty-one patients (50%) had CM at BL, 35 (42.68%) at Y1. AP fusion patients had least levels fused (6.4 AP, 11.4 PIB, 11.8 PSF, p<0.001). No difference in revision by approach (55.56% AP, 24.39% PIB, 28.13% PSF, p=0.179). Approach type was not associated with different BL, Y1 or DELTABL-Y1 alignment parameters for FC, CA or SA. Mean FC 9.89degree at BL, 6.91degree at Y1 and DELTABL-Y1 difference 5.77degree, no difference between approach groups (p=0.361, 0.127, 0.550, respectively). Mean value for CA 33.62mm at BL, 21.15mm at Y1 and DELTABL-Y1 difference 23.23mm, no difference between approach groups (p=0.087, 0.153, 0.206, respectively). Mean PI-LL 25.21degree at BL, 11.1degree at Y1 and DELTABL-Y1 difference -13.7degree, no difference between approach groups (p=0.503, 0.600, 0.356, respectively). Mean cSVA 27.53degree at BL, 28.85degree at Y1 and DELTABL-Y1 difference 1.29degree, no difference between approach groups (p=0.364, 0.099, 0.141, respectively). Mean TPA 28.37degree at BL, 21.12degree at Y1 and DELTABL-Y1 difference -6.63degree, no difference between approach groups (p=0.066, 0.248, 0.138, respectively).
CONCLUSION(S): Fusion to the sacrum/pelvis improves sagittal alignment, fractional curve and coronal alignment in most patients. However, while fractional curve and sagittal alignment are better corrected, coronal malalignment, particularly more severe malalignment at baseline, tends to persist postoperatively. Type of approach and use of interbody device does not appear to significantly impact these results. This should be considered in preoperative planning for patients with coronal deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Cannabis is the most commonly used illicit drug in the United States, and with changing state legislation, the use of cannabis is expected to expand. Although other literature has noted potentially medicinally beneficial effects of cannabis, there is limited literature evaluating the impact of cannabis on outcomes for patients following spinal surgery. With shifting public sentiment, expanding decriminalization, and a dearth of knowledge on the potential surgical implications of cannabis, it is imperative we take a closer, objective look at how cannabis dependence or abuse impacts the outcomes of common orthopedic procedures, such as thoracolumbar fusion. PURPOSE: To determine if adverse outcomes would be comparable between baseline cannabis users and non-cannabis users undergoing thoracolumbar spinal fusion. We compared the rates of 90-day outcomes and complications and 2-year revisions between baseline cannabis users and non-users following thoracolumbar spinal fusion. STUDY DESIGN/SETTING: Retrospective cohort study of a prospectively-collected database. PATIENT SAMPLE: The New York State Statewide Planning and Research Cooperative System (SPARCS) was queried to identify all patients from January 2009 to September 2013 who underwent thoracolumbar spinal fusion. Patients were included if they had <=90-day follow-up for complications and readmissions or >=2-year follow-up for revisions. Patients with preoperative cannabis abuse/dependence were identified. Patients were excluded for systemic disease, osteomyelitis, cancer, trauma, or concomitant substance or polysubstance abuse/dependence. OUTCOME MEASURES: Demographic information, fusion approach, fusion levels, complications, readmissions, and revisions.
METHOD(S): The NYS SPARCS database was queried to identify all patients >=18y who underwent thoracolumbar spinal fusion from 2009-13. Patients were included if they had <=90D FU for complications and readmissions or 2Y FU for revisions. Patients with preoperative cannabis abuse/dependence were identified. Patients were excluded for systemic disease, osteomyelitis, cancer, trauma, or concomitant substance or polysubstance abuse/dependence. Following patient identification in the SPARCS database, patients with ICD-9-CM diagnosed cannabis use were 1:1 propensity score-matched by age, gender, race, Deyo score, fusion levels and approach and tobacco use to non-cannabis users. These groups were compared for hospital-related parameters, rates of 90-day complications and readmissions and 2-year revisions. Multivariate binary stepwise logistic regression models identified independent predictors of outcomes.
RESULT(S): A total of 628 patients (n=314 each) were identified and included; patients had comparable age, gender, fusion approaches and fusion levels distribution. More cannabis patients were African American (19.7 vs 7.6%) and primarily utilized Medicaid (24.2% vs 11.5%), all p<=0.001. Non-cannabis patients incurred lower 90-day overall and medical complication rates (5.1% vs 12.1%; 4.5% vs 9.9%), all p<0.01. Regression revealed baseline cannabis use as a negative independent predictor of any 90-day medical complications (OR=0.43, p=0.01). Baseline cannabis use was not associated with increased surgical or overall 90-day complications, 90-day readmissions or 2-year revisions.
CONCLUSION(S): Cannabis was a protective factor against postoperative anemia and any medical complication, and baseline cannabis use was not associated with increased surgical or overall 90-day complications and readmissions or 2-year revision rates. These findings underscore that baseline cannabis use in the absence of acute intoxication may not necessarily require delays in preoperative clearance. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adult Spinal Deformity (ASD) surgery is associated with a high cost. Previous studies have suggested that the actual direct hospital cost of ASD surgery is higher than the Medicare Allowable (MA) rate. MA rates are becoming the benchmark reimbursement target for hospital accounting systems. It is important to determine what factors can predict which ASD patients have actual costs below Medicare reimbursement. PURPOSE: Our goal is to (1) determine if we can develop a model to predict when index episode of care (iEOC) surgical costs of ASD surgeries are below the MA threshold and (2) to identify potentially modifiable variables. STUDY DESIGN/SETTING: Retrospective analysis of a prospective multi-center ASD database. PATIENT SAMPLE: Adult spinal deformity patients undergoing surgical correction enrolled into a prospective, multicenter surgical database from 2008-2014. OUTCOME MEASURES: Primary outcome measure is iEOC costs and patient and hospital-specific MA reimbursements, but other baseline HRQOL outcome measures were collected such as Oswestry Disability Index (ODI), SF-36 PCS, and SF-36 MCS.
METHOD(S): From a prospective, multicenter ASD surgical database, patients undergoing long instrumented fusions (>4 level) with cost data were identified. Index episode of care (iEOC) cost was calculated by utilizing actual direct hospital cost. MA rates were calculated using the year-appropriate CMS Inpatient Pricer Payment System Tool and were hospital specific. Demographic, baseline HRQOL, radiographic and surgical variables were analyzed. A predictive model was developed to identify variables that can predict iEOCRESULT(S): Administrative direct cost data was obtained from 4 of 11 centers with a total of 195 patients included in the model. A total of 109 (55%) patients had iEOC below the MA threshold. There was significant variation across the 4 centers in both the mean iEOC cost ($56,788 to $78,878,p<0.001) and reimbursement ($40,623 to $91,351, p<0.001) which was seen across deformity-specific DRGs (453,454,456,457). Academic centers were more likely to have iEOC costs below reimbursement (66.7% vs 8.9%, p<0.001). The model showed excellent fit and calibration with an AUC of 94.48% [95%CI 91.59-97.38]. Negative predictors included number of levels fused (OR 0.61, 95%CI [0.48-0.75], p <0.001) and DRG 457 (OR 0.016, 95%CI [0.0-0.20], p = 0.0016) while having a revision surgery (OR 3.61, [1.06-13.58], p=0.045) and at an academic center (OR 19.6 95%CI [8.81-50.7], p <0.001) were positive predictors. The marginal effect for additional levels fused is -4.38%, meaning for each additional level fused, the likelihood of the iEOCCONCLUSION(S): There is significant institutional variation in ASD cost and reimbursement with an increased likelihood of 56.8% getting reimbursed more than the cost of surgery (iEOCCopyright

BACKGROUND CONTEXT: In the past, averages from published studies have been used for performance benchmarking. However, in practice and in large studies, usually only a small subset of patients fall within the "average" and therefore the average may not provide a valid benchmark rate. One can overperform or underperform the average and still attain the predicted performance benchmark. Predictive modeling can be used to help set performance standards based on a large number of variables including patients' specific factors, procedure details, use of osteogenic products, site specific variations and many others. This study attempts to use predictive modeling for pseudarthrosis performance benchmarking as a proof of concept in ASD surgery. PURPOSE: To use predictive modeling for performance benchmarking in high-volume centers and demonstrate that it is more appropriate than simply using averages. STUDY DESIGN/SETTING: Retrospective review of a prospective, multicenter ASD database from 11 different sites PATIENT SAMPLE: ASD operative patients with age >=18, Coronal Cobb >= 20deg, SVA >=5cm, PT>=25deg, and/or thoracic kyphosis (TK) >= 60deg with min 2-year follow-up. Exclusion criteria: having a revision for any indication other than pseudo in order to reduce confounding of potential pseudo as a result of the revision surgery. OUTCOME MEASURES: HRQOL scores: Oswestry Disability Index (ODI), Short form-36 (SF36), Scoliosis Research Society (SRS22), back/leg pain numerical rating scale (NRS). Radiographic values: max coronal cobb angle, coronal C7 plumb line, pelvic tilt (PT), mismatch between pelvic incidence and lumbar lordosis (PI-LL), thoracic kyphosis (TK), C7 sagittal vertical axis (SVA). Posterior fusion was graded to determine if pseudo has occurred within 2 years postoperative. Demographic, frailty, surgical including BMP and complications data were also collected.
METHOD(S): A prior validated and published pseudo predictive model has been constructed from 336 ASD patients with an accuracy of 91.3% and an AUC of 0.94 using 21 out of 82 total variables listed above. This model was deployed with an updated set of patients to determine the predicted pseudo rate for each individual surgical site. Actual pseudo rates of the 11 contributing surgical sites were compared to the predicted values as a means to assess for performance benchmarking.
RESULT(S): A total of 403 patients were included (80.1% Female, avg age 57.9+/-14.9 years) from a total of 502 operative patients with 99 excluded for having a revision for indication other than pseudo. A total of 129 (32.0%) had pseudo by 2 years. The overall pseudo rates per year were the following: 2008-20.0%, 2009-37.7%, 2010-31.4%, 2011-29.3%, 2012-36.7%, 2013-32.0%, 2014-26.6%, 2015-38.1%. Six sites had actual rates above the overall rate of 32% with 5 sites below. However, the predicted rates varied according to each site and included rates above/below the overall rate. All of the actual rates were larger than the predicted rates except for 4 sites in which the actual and predicted rates were the same.
CONCLUSION(S): The pseudo rate varied per year and per site. Predictive modeling was able to provide a customized pseudoarthosis rate for each site considering multiple variables allowing for performance benchmarking instead of the average. Even though a site was above the overall average rate, they may be predicted to have a higher rate given the type of patients being treated or procedures done at that site. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adult Spinal Deformity (ASD) surgery significantly improves disability in patients who are functionally limited. Few studies have been done examining the threshold at which surgery is unlikely to provide functional benefit in ASD patients. PURPOSE: To identify a preoperative threshold at which patients who are more active than this threshold are unlikely to have functional improvement following ASD surgery, and may experience functional decline. STUDY DESIGN/SETTING: Retrospective review of a multicenter database. PATIENT SAMPLE: A total of 592/760 (78%) eligible ASD patients (>5 levels fused) were identified in a multicenter database with minimum 2-year follow-up. OUTCOME MEASURES: Our primary outcome was baseline-2 year postoperative change in Scoliosis Research Society 22r (SRS-22r) Activity domain.
METHOD(S): The SRS-22r was administered at preoperatively and at follow-up visits through 2-years. A baseline SRS-22r Activity score threshold was identified at which patients were more likely to decline than improve at 2-years postoperatively. Categorical variables were compared with chi-squared test. Significance was set at 0.05.
RESULT(S): Mean age of patients was 59+/-14 years, 80% females. Patients had 11.2+/-4.3 levels fused; follow up of 3.8+/-0.9 years. A baseline SRS-22r threshold of 3.8 was identified at which 44 (52%) patients above this threshold declined and 40 (48%) had improved activity at 2-year follow-up. In patients who declined, mean change was -0.6+/-0.43 points. Patients above this threshold were younger, had less severe deformity, and less back/leg pain (p<0.001). Most patients worse than this threshold reported SRS-22r Pain as the most severe domain (51%), while most patients better than this threshold reported the SRS-22r appearance as the worst domain (58%) (p<0.001). Patients above and below this threshold were equally likely to be satisfied with their surgery at 2 years (p=0.92).
CONCLUSION(S): Baseline SRS-22r Activity score can be used to risk-stratify ASD patients by likelihood of functional improvement postoperatively. Patients doing better than this threshold are just as likely to be satisfied as more disabled patients at 2 years, likely due to improvement in appearance, pain or mental health rather than activity level. In patients with SRS-22r activity above 3.8, the potential for minimal functional benefit should be included in the shared decision making process. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Sexual function is an important contributor to quality of life. Adult spinal deformity (ASD) patients have been shown to have sexual limitations due to their deformity. PURPOSE: This investigation sought to assess sexual dysfunction due to lumbar stiffness before and after fusion surgery. STUDY DESIGN/SETTING: Retrospective analysis of a multi-center, prospectively-collected, consecutive cohort of ASD patients. PATIENT SAMPLE: Only patients with 2-year follow-up were included. In total, 365 patients were included in this study, comprising 76 males and 289 females. OUTCOME MEASURES: The primary outcome in this study was the Lumbar Spine Disability Index (LSDI) question 10: "Choose the statement that best describes the effect of low back stiffness on your ability to engage in sexual intercourse." METHODS: Differences in sexual function between baseline and 2-year follow-up were assessed with a Wilcoxon-Mann-Whitney test. Patient factors associated with poor baseline sexual function were evaluated with multiple linear regression. The association between sexual function and HRQOL at baseline and 2-year follow-up was evaluated with multiple linear regression, adjusting for all factors previously included in analyses of baseline sexual function.
RESULT(S): Baseline LSDI sexual function scores averaged 2.7 (SD 1.3), which improved to 2.3 (SD 1.2) at 2-year postsurgical follow-up (p = 0.0009). Predictors of poorer baseline sexual function included older age, BMI, and higher Charlson Comorbidity Index (p<0.05 for all comparisons). After adjusting for confounding factors, worse LSDI sexual function score was strongly associated with worse ODI, SRS total, and SF-36 PCS at both baseline and 2-year follow-up (p<0.001 for all comparisons).
CONCLUSION(S): This study found that sexual dysfunction due to lumbar stiffness is strongly related to HRQOL measures such as ODI and SRS-22r total score. Further, sexual function was not diminished postoperatively, possibly due to reduced pain that accompanied improved stability. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: The Roussouly Classification system of sagittal spinal shape and the SRS-Schwab adult spinal deformity (ASD) classification system have become important indicators of spine deformity. No prior studies have examined the outcomes of matching both Roussouly type and improving in Schwab modifiers postoperatively. PURPOSE: Evaluate outcomes of matching Roussouly Type and improving in Schwab modifier following ASD surgery. STUDY DESIGN/SETTING: Retrospective review of single-center ASD database. PATIENT SAMPLE: A total of 103 ASD patients. OUTCOME MEASURES: Roussouly types, Schwab modifiers, Health Related Quality of Life scores(HRQLs): Minimal Clinical Important Difference for ODI, EQ5D, VAS Leg &Back Pain.
METHOD(S): Surgical ASD patients (SVA>=5cm, PT>=25degree, or TK >=60degree, >3 levels fused) >=18 years old with available baseline (BL) radiographic data at baseline (BL) and 1-year (1Y) were isolated in the single-center Comprehensive Spine Quality Database (Quality). Patients were grouped by two Roussouly types: (1)"theoretical" Roussouly type(Type 1: PI<45degree, LL apex below L4; Type 2: PI<45degree, LL apex above L4 L4-L5 space; Type 3: 45degree60degree); (2) "current" Roussouly type (1: SS<35degree, LL apex below L4; 2: PI<35degree, LL apex above L4-L5 space; 3: 35degree45degree), as previously published. One year (1Y) matched Roussouly: preoperative mismatched (Between 'actual' and 'theoretical' patients that matched at 1Y. Schwab modifiers at BL were identified: non-, moderate and severe deformity (0, +, ++) for PT, SVA, and PI-LL. Schwab improvement was defined as a decrease in a modifier at one year.
RESULT(S): A total of 103 ASD patients (61.8yrs, 63.1%F, 30kg/m2). By surgical approach, 79.6% posterior, 10.7% combined, 2.9% anterior). Average levels fused: 4.6. BL breakdown of 'current; Roussouly type: 28% Type 1, 25.3% Type 2, 32.0% Type 3, 14.7% Type 4. BL Roussouly mismatch: 65.3%. Breakdown BL Schwab modifiers: PT (0: 8.7%, +: 41.7%, ++: 49.5%), SVA (0: 29.7%, +: 20.3%, ++: 50%), PI-LL mismatch (0: 28.2%, +: 25.2%, ++: 46.6%). At one year, 19.2% of patients matched Roussouly target type, while according to Schwab modifiers, 12.6% improved in SVA, 42.7% in PI-LL, and 45.6% in PT. Patients who both met Roussouly type and improved in a Schwab by the modifiers: 9 PT (8.7%), 8 PI-LL (7.8%), 2 SVA (1.9%). There were 2 patients (1.9%) who met their Roussouly type and improved in all 3 Schwab modifiers. One year (1Y) matched Roussouly patients improved more in HRQLs (MCID for ODI, EQ5D, VAS Leg/Back Pain), when compared to mismatched Roussouly, but was not significant(P>0.05). Match Roussouly and improvement in PT Schwab met MCID for EQ5D significantly more (33.3% vs 10.6%, p=0.050). Matched Roussouly and PI-LL Schwab had more patients meet MCID for all HRQLs, yet none were significant, p>0.05. Matched Roussouly and improvement in SVA Schwab met MCID for ODI significantly more (p=0.024).
CONCLUSION(S): Patients who both matched Roussouly sagittal spinal type and improved in SRS-Schwab modifiers had superior patient-reported outcomes at 1-year. Utilizing both classification systems in surgical decision making can optimize postop patient outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Despite increased recognition of the clinical benefit of optimal sagittal realignment among symptomatic ASD patients, persistent malalignment remains prevalent following corrective surgery. Following surgery it remains difficult to predict the changes in truncal inclination and pelvic retroversion depending on segmental and regional correction of the lumbar spine. PURPOSE: Establish simultaneous focal and regional corrective guidelines accounting for reciprocal global and pelvic compensation STUDY DESIGN/SETTING: Retrospective review of a prospective database PATIENT SAMPLE: A total of 433 Surgical Adult Spinal Deformity (ASD) patients with 2-year follow-up. OUTCOME MEASURES: Prediction of postoperative sagittal alignment (PT, SVA and TPA).
METHOD(S): Patients were included based on the presence of radiographic ASD and having undergone corrective realignment at minimum incorporating L1-pelvis. Established sagittal radiographic parameters, as well as segmental and regional (T10-L1, L1-L4, and L4-S1) Cobb angles were assessed prior to and following surgery. To distinguish the impact of the realignment on pelvic versus truncal inclination a virtual postoperative alignment was generated by combining postoperative alignment of the fused spine with the preoperative alignment on the unfused thoracic kyphosis and the preoperative pelvic retroversion. Incorporating virtual alignment, regression models were then generated to predict the relative impact of segmental (L4-L5) and regional (L1-L4) corrections on PT, SVA (virtual), and TPA.
RESULT(S): A total of 433/667 patients were included (mean age 62.9 years, 81.3% women). Following surgical intervention significant improvement of sagittal alignment occurred; PI-LL (21degree to 4degree), PT (26degree to 23degree), SVA (79mm to 33mm) and TPA (26degree to 19degree)(all p<0.001). Regarding segmental and regional alignment, baseline analysis revealed a distal lordosis of 33+/-15degree, a flat proximal lordosis (1.7+/-17degree), and segmental kyphosis from L2-L3 to T10-T11. Following surgery, there was no mean change in distal lordosis (L5-S1 decreased by 2degree, and L4-L5 increased by 2degree), while the more proximal lordosis increased by 18+/-16degree. Regression analysis based on the virtual alignment yielded the following equations: PT = 2.42 - 0.46*L4S1 - 0.35*L1L4 - 0.23*T10L1 (r-square = 0.65, mean error -0.2degree, RMSE 5.5degree)TPA = -0.75*L4S1 - 0.55*L1L4 - 0.36*T10L1 (r-square = 0. 95, mean error: -0.3degree, RMSE 4.3degree)SVA = -8*L4S1 -6.14*L1L4 - 4*T10L1 (r-square = 0. 95, mean error: -2.6mm RMSE 50mm). Summarily, a 10degree in distal lordosis resulted in a 10degree in TPA, associated with 100mm in SVA or 3degree in PT; 10degree in proximal lordosis yields 5degree in TPA associated with 50mm in SVA; and finally 10degree in thoraco-lumbar junction yields 2.5degree in TPA associated with 25mm in SVA and no impact on PT correction.
CONCLUSION(S): This study establishes that the overall impact of lumbar lordosis restoration is critically determined by the location of the correction. For any given amount of lordosis correction, a distal correction leads to a greater impact on global alignment and pelvic retroversion. More specifically, it can be assumed that 1degree L4-S1 correction implies 1degree change in TPA / 10mm change in SVA and 0.5degree in PT. Based on regional objectives (PI-LL) and global perspectives (TPA/SVA and PT), preoperative planning can be adjusted to optimize realignment. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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