Faculty Bibliography

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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BACKGROUND CONTEXT: The current proposed cervical deformity (CD) classification system including cutoffs for C2-C7 sagittal vertical axis(cSVA), T1 slope minus C2-C7 lordosis (TS-CL), Chin Brow Vertical Angle (CBVA), and the modified Japanese Orthopaedic Association scale(mJOA) are based upon a modified Delphi approach and expert opinion. PURPOSE: To investigate the relationship between cervical parameters and the Health Related Quality of Life (HRQL) measure, mJOA. STUDY DESIGN/SETTING: Retrospective review of a prospective, consecutively enrolled CD database. PATIENT SAMPLE: A total of 123 CD patients. OUTCOME MEASURES: CD modifiers; HRQL Instrument: mJOA; Radiographic thresholds for moderate (M) and severe (S) deformity.
METHOD(S): Included: surgical adult CD patients (C2-C7 Cobb>10degree, CL>10degree, cSVA>4cm, or CBVA>25degree). Radiographic parameters measured: C2-C7 lordosis (CL), T1 slope, C2-C7 SVA, TS-CL, C2-T3 angle, C2 slope, pelvic tilt (PT). Measured HRQLs: Reported mJOA scores, categorized by Tetreault et al.: 18 as none, 15-17 as mild, 12-14 as moderate and <12 as severe. Other modifiers assessed: McGregor slope (MGS), CBVA and frailty. Statistical analyses were performed to determine correlations between HRQLs and possible modifiers. After determining data followed a parametric distribution using the Shapiro Wilk Normality test (p=0.15, p>0.05), Pearson correlations were run for all combinations. For significant correlations, linear and binary logistic regressions were performed to determine a possible threshold of radiographic measures for which the correlation with mJOA scores was most significant. A mJOA score of 14 and <12 that are reported cut off values for moderate and severe disability.
RESULT(S): A total of 123 CD patients were included (60.5+/-10.1 years, 65% female, 29.1+/-8.2 kg/m2). The average Charlson Comorbidity Index (CCI) score was 0.90. Cohort surgical factors included, by approach, 17.1% anterior, 50.4% posterior and 32.5% combined. Average anterior levels fused was 3.36, while the average posterior levels fused was 8.93, and the total average was 8.05 levels fused. The mean total operative time was 534.3 minutes, with an estimated blood loss (EBL) of 890.6 ccs. Baseline mJOA score was 13.54+/-2.8. Pearson correlations determined significant correlation between baseline mJOA scores and McGregor's Slope (-0.236, p=0.015), TS-CL (-0.246, p=0.006), CL (0.225, p=0.012), C2-T3 (0.180, p=0.046), C2 Slope (-0.234, p=0.009), and frailty (0.517, p<0.001), and no significant correlation with T1 slope, cSVA, CBVA and PT. Logistic regression models assigned values as binary variables greater or less than a predicted threshold value, tested at increments. For significant baseline factors from the Pearson correlation, the following rough thresholds were predicted: MGS (M: -12 to -9degree and 0 to 19degree, p=0.020; S: >19degree and <-12degree, x2= 4.291, p=0.036), TS-CL (M: 26degreeto 45degree, p=0.307; S: >45degree, x2= 7.8, p=0.005), CL (M: -21degree to 3degree, x2= 8.947, p=0.004; S: >3degree, x2 =9.3, p=0.009), C2-T3 (M: -35degree to -25degree, x2 = 5.485, p=0.046; S: >-25degree, x2 = 4.1, p=0.041), C2 Slope (M:33degreeto 49degree, p=0.122; S: >49degree, x2=5.7, p=0.008), and Frailty (Mild: 0.18 to 0.27, p=0.129; Severe: >0.27, p=0.002).
CONCLUSION(S): Novel thresholds were established for McGregor's Slope, TS-CL, C2-T3 angle, C2 Slope and frailty. Each correlated with moderate or severe neurologic myelopathy HRQL by way of mJOA score. These cut-off values can be utilized in classifying cervical deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: In the current value-based health care climate where spinal surgery is shifting to the ambulatory setting, factors influencing postoperative patient length of stay (LOS) have significance to both surgeons and hospital administrators. Underlying patient factors including the diagnosis of radiculopathy and myelopathy have not been investigated in this context. PURPOSE: Identify predictors extended LOS(E-LOS) between myelopathy(M), radiculopathy(R), and patients with both (MR). STUDY DESIGN/SETTING: Retrospective review of a single-center stereographic database. PATIENT SAMPLE: A total of 718 surgical cervical spine patients. OUTCOME MEASURES: Postoperative LOS, patient factors, preoperative HRQL, complications, predictors of E-LOS.
METHOD(S): Surgical cervical spine patients >=18yrs diagnosed with M or R primary diagnoses were isolated in the single-center Comprehensive Spine Quality Database (Quality). Patients were stratified by surgical approach: Anterior, Posterior or Combined. Top-quartile LOS values were labeled as extended. M and R patients were compared using chi-squared and independent samples t-tests, as appropriate. Univariate tests assessed differences in baseline patient-related and surgical data between M and R, and extended/non-extended LOS. Univariate/multivariate analyses were run to assess predictive factors of E-LOS in each diagnosis group. Regression with stepwise model selection was employed to explore factors potentially significant in predicting LOS.
RESULT(S): A total of 718 patients (54.5 years, 41.1%F, 29.1kg/m2). Mean CCI score: 1.11. Within the cohort, 177 patients (24.7%) had a diagnosis of myelopathy, 383 (53.3%) radiculopathy, and 22% with a diagnosis of myeloradiculopathy. Patients with M primary diagnosis were significantly older (62.2 vs 49.8yrs, p<0.001) and had a greater CCI score (1.64 vs 0.82, p<0.001) when compared to R patients. By approach: 76.7% anterior (57.6% of M, 90.6%R, 64.6%MR; p<0.001), 16.4% (35%M, 6%R, 20.9%MR; p<0.001) posterior, 6.5% (6.8%M, 3.4%R, 13.9%MR; p<0.001) combined. Average LOS: M(3.8days), R(1.5 days), MR(2.9 days) p<0.001. LOS for anterior approach in each diagnosis was as follows, M: 2.21, R: 1.21, MR: 1.69 days, p<0.001. Meanwhile, posterior approach LOS, M:6.06, R:2.91, MR:5.0, p<0.001; combined approach M: 5.17, R: 6.23, MR: 5.59, P=0.881. A total of 195 patients were categorized as E-LOS (Avg: 5.87 days), 87 M, 43 R, 65 MR. Major surgical approach of E-LOS for M (60.9%) and MR (44.6%) was posterior; whereas R E-LOS patients majorly underwent anterior procedures (53.5%). Generalized linear regression modeling found that the following combination of factors predicted E-LOS in R patients (R2=0.736, p=0.003):BMI, durotomy, CCI, anterior and combined approaches, and cardiac complications. An additional model discovered the predictors of E-LOS in M patients (R2= 0.312, p<0.001): age, hypertension, CCI, anterior and combined approaches, intraoperative complications, neuro complications, ileus, and return to OR in 90 days. Lastly, the model for E-LOS in MR patients consisted of (R2 = 0.267, p=0.001): age, durotomy, BL EQ5D, hypertension, posterior and combined approaches and postoperative complications, specifically neuro.
CONCLUSION(S): Independent of surgical approach, patients with a primary diagnosis of myelopathy, though older aged and higher comorbidity profile, had consistently longer overall postop LOS when compared to radiculopathy or myeloradiculopathy patients. The heightened risk in myelopathy patients for extended LOS should be considered when determining admission status for patients undergoing cervical spine surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Recent studies have evaluated the correlation of health-related quality of life (HRQL) scores with radiographic parameters. This relationship may provide insight into the connection of patient-reported disability and disease burden caused by cervical diagnoses. PURPOSE: To evaluate the association between spinopelvic sagittal parameters and HRQLs in patients with primary cervical diagnoses. STUDY DESIGN/SETTING: Single center retrospective review. PATIENT SAMPLE: A total of 90 cervical operative patients. OUTCOME MEASURES: Spinopelvic sagittal parameters; Regional cervical alignment parameters; HRQL Outcome Instruments: modified Japanese Orthopedic Association scale (mJOA), Neck Disability Index (NDI).
METHOD(S): Patients >18yrs meeting criteria for primary cervical diagnoses(cSVA<4cm). Measured HRQLs: Reported mJOA scores, categorized by Tetreault et al.: 18 as none, 15-17 as mild, 12-14 as moderate, <12 as severe; NDI score cut-offs established by Vernon et al. (multiplied by 2 for this database) 0-8 no disability, 10-28 mild, 30-48 moderate, 50-68 severe, >68 complete disability. Cervical radiographic parameters assessed: cSVA, TS-CL, CBVA, C2-T3, CL, C2 Slope, MGS etc. Global radiographic alignment parameters assessed: PT, SVA, PI-LL, T1 Slope. Statistical analyses were performed to determine correlations between HRQLs and possible modifiers of CD. Pearson correlations were ran for all combinations at baseline (BL) and 1-year(1Y) for continuous BL and 1Y mJOA scores, as well as decline or improvement in those HRQLs at 1Y. Multiple linear regression models were constructed to investigate BL and 1Y alignment parameters as independent variables.
RESULT(S): A total of 90 patients included (55.6 years, 52%F, 30.7+/-7kg/m2). By approach, 14.3% of patients underwent procedures by anterior approach, 56% posterior, and 30% had combined approaches. Average anterior levels fused: 3.6, posterior: 4.8, and mean total number of levels fused: 4.5. Mean operative time for the cohort was 902.5 minutes with an average estimated blood loss of 830 ccs. The mean baseline NDI score was 56.5, and a mJOA of 12.81. While BL NDI score correlated with gender (p=0.050), it did not correlate with BL global or cervical radiographic factors. An increased NDI score at 1-year postoperatively correlated with BL BMI(p=0.026). A decreased NDI score was associated with 1Y T12-S1 angle (p=0.009) and 1Y T10 L2 angle (p=0.013). Overall, BL mJOA score correlated with the BL radiographic factors of T1 slope(p=0.005), cervical lordosis(p=0.001), C2-T3(p=0.008), C2 sacral slope(p=0.050), SVA(p=0.010), and CL Apex(p=0.043), as well as gender(p=0.050). Linear regression modeling for the prior independent variables found a significance of p=0.046 and an R2 of 0.367. Year 1 mJOA scores correlated with 1Y values for maximum kyphosis(p=0.043) and TS-CL(p=0.010). At 1Y, a smaller mJOA score correlated with BL S1 sacral slope(p=0.014), pelvic incidence(p=0.009), L1-S1(p=0.012), T12-S1(p=0.008). The linear regression model for those 4 variables demonstrated an R2 of 0.169 and a p-value of 0.005. An increased mJOA score correlated with PI-LL difference at 1Y(p=0.012), L1-S1 difference(p=0.036), T12-S1 difference (0.006), maximum lordosis(p=0.026), T9-PA difference(p=0.010), and difference of T4-PA(p=0.008).
CONCLUSION(S): While the impact of preoperative sagittal and cervical parameters on mJOA was strong, the BL radiographic factors did not impact NDI scores. PostOp HRQL was significantly associated with sagittal parameters for mJOA (both worsening and improvement) and NDI scores (improvement). When cervical surgery has been indicated, radiographic alignment is important for PostOp HRQL. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Distal junctional kyphosis (DJK) is a major concern following cervical deformity (CD) correction, leading to failed realignment and revision surgery. Undercorrection may be the major factor associated with DJK, however it is difficult to assess because the DJK erodes the correction and worsens traditional measures like cSVA. In-construct measures have been proposed that measure alignment within the fusion separate from the DJK and subjacent compensation. PURPOSE: To simulate cervical deformity corrections using surgical planning software to determine if undercorrection results in DJK. STUDY DESIGN/SETTING: Retrospective analysis of a prospective, multicenter CD database. PATIENT SAMPLE: A total of 69 CD patients. OUTCOME MEASURES: Radiographic measures: C2 plumblines, in-construct measures and DJK angle change.
METHOD(S): A prospective database of operative CD patients was analyzed for severe DJK (kyphosis change>20degree in LIV to LIV-2) and traditional DJK (change>10degree). C2LIV-Tilt (angle of a line from the centroid of C2 to the centroid of the lower instrumented vertebra and a line along the posterior vertebral body wall of the LIV) was measured postoperatively and the correction was simulated in the preoperative X-ray to match the C2LIV-Tilt using planning software. Linear regression analysis using C2 pelvic angle (CPA) and Pelvic Tilt (PT) determined the simulated PT to match the virtual CPA. SVA measures were compared in patients with severe and traditional DJK and no DJK. Linear regression analysis was used to determine the C2-T4 and C2-T10 Tilts that correspond to DJK=10degree and cSVA=4cm.
RESULT(S): A total of 69 CD patients (mean age 61, 60% female) were included. Severe and traditional DJK occurred in 11 (16%) and 22 (32%) patients; 3 (4%) required DJK revision. Simulated corrections demonstrated that severe and traditional DJK pts had worse alignments compared to no DJK pts: cSVA (42.5 vs 33.0 vs 23.4mm, p<.001), C2-T3 SVA (74.5 vs 61.8 vs 41.4mm, p<.001), C2-LIV SVA (68.9 vs 57.3 vs 36.8mm, p<.001). Linear regression revealed a predictive relationship between in-construct measures (C2T4-Tilt and C2T10-Tilt) and cSVA and change in DJK (all R>.57, p<.001). cSVA=4cm corresponded to C2T4-Tilt of 10.4degree and C2T10-Tilt of 28.0degree. DJK change=10degree corresponded to C2T4-Tilt of 5.8degree and C2T10-Tilt of 20.1degree. Severe DJK pts had the worst postoperative alignment by all measures including cSVA, TSCL, CPA, C2LIV-Tilt, (all p<.001).
CONCLUSION(S): Simulated cervical deformity corrections demonstrated that severe DJK patients have insufficient corrections compared to patients without DJK. In-construct measures assess sagittal alignment within the fusion separate from DJK and subjacent compensation. They can be useful as intraoperative tools to gauge the adequacy of CD correction. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Computer adaptive testing is becoming increasingly common in assessing patient outcomes. The Patient Reported Outcome Measurement Information System (PROMIS) instruments of Physical Function, Pain Intensity and Pain Interference have been shown to correlate with established patient outcome metrics. There is a lack of studies investigating the relationship between PROMIS physical health domain metrics and established Ames cervical deformity (CD) radiographic classification. PURPOSE: To evaluate the association of available cervical alignment components via the Ames cervical deformity classification parameters with PROMIS physical domains. STUDY DESIGN/SETTING: Retrospective review of a single-center stereoradiographic database. PATIENT SAMPLE: A total of 208 CD patients with complete baseline radiographic and PROMIS data. OUTCOME MEASURES: PROMIS metrics [Pain Intensity (PI), Physical Function (PF), Pain Interference] and Ames CD modifiers [cSVA, TS-CL].
METHOD(S): Surgical CD patients (C2-C7 Cobb angle >10degree or C2-C7 sagittal vertical axis >4cm or TS-CL>15degree) >=18 years old with available baseline (BL) radiographic and PROMIS data were isolated in the Spine Quality Database (Quality). Patients were classified according to Ames CD modifiers for cSVA and TS-CL (non-deformed [Non], moderate deformity [Mod], severe deformity [Sev]). Descriptives and univariate analyses compared population-weighted PROMIS scores for PI, PF, and Interference across CD deformity modifiers. Conditional Tree Analysis with logistic regression sampling were performed to determine a possible threshold of PROMIS scores for which the correlation with Ames radiographic cut-offs was most significant. Reported cut off values for Mod (cSVA: 4-8cm; TS-CL: 15-20degree) and Sev (cSVA: >8cm; TS-CL: >20degree) disability were used.
RESULT(S): A total of 208 pts (58.8yrs, 51%F, 29.6kg/m2, mean Charlson Comorbidity score: 1.19) met inclusion criteria. By surgical approach: 79.3% posterior, 5.7% anterior, 14.9% combined; mean levels fused: 3.7+/-4.2. Baseline cervical cSVA modifier by severity: 83.2% Non, 16.8% Mod. No patients met criteria for severe cSVA modifier. Baseline TS-CL modifier by severity: 18.8% Non, 22.1% Mod, 59.1% Sev. Mean PI score: 89.6+/-15.4, mean PF score: 11.9+/-13.1, mean Int score: 56.9+/-6.8. PI did not differ between cSVA or TS-CL modifier severity. Mod cSVA patients and Mod/Sev TS-CL modifier groups both trended towards lower PF scores and higher pain interference scores though this was not significant (P>0.05). Conditional tree analysis determined thresholds for PROMIS scores that were independent predictors of modifier severity. A PI score>96(OR: 0.658[0.303-1.430]), a PF score<14 (OR:1.864[0.767-4.531]) and an interference score of >57.4 (OR: 1.712[0.811-3.616]) were predictors of Mod cSVA. A PI score of >87(OR: 1.428[0.767-2.659]), a PF score <14 (OR: 1.551[0.851-2.827]), and a pain interference score of >56.3 (OR:1.656[0.946-2.897]) were predictors of Sev TS-CL.
CONCLUSION(S): PROMIS physical health domain metrics of Pain Intensity, Physical Function, and Pain Interference were related to cervical malalignment parameters of the Ames cervical deformity classifications system. Certain baseline PROMIS thresholds can be connected to severity of cervical deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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