Faculty Bibliography

BACKGROUND CONTEXT: Adult spinal deformity is associated with severe pain and disability. Recent literature has shown that surgical intervention can significantly improve patient's quality of life and lessen disease burden. As many patients requiring spine surgery are elderly and often frail, restoration of alignment targets may differ. There is paucity in literature on whether different frailty and deformity states may warrant a different level of surgical invasiveness. PURPOSE: To investigate the effect of frailty and deformity severity on appropriate surgical invasiveness. STUDY DESIGN/SETTING: Retrospective cohort study from multicenter database. PATIENT SAMPLE: This study included 381 adult spinal deformity (ASD) patients. OUTCOME MEASURES: Complications; health-related quality of life (HRQL); Oswestry Disability Index (ODI).
METHOD(S): Operative ASD patients (scoliosis >20, SVA>5cm, PT>25, or TK>60) with available baseline (BL) and 2-year (2Y) radiographic and HRQL data were included. The ASD-FI was used to stratify patients into 2 categories: Not Frail (NF): 20. Four groups were formed by frailty and deformity severity: NF Low, F Low, NF Sev, F Sev. ANCOVA determined differences in Surgical Invasiveness (SI) among F/D groups. Logistic regression determined significant association between SI and reaching Ideal Clinical outcome (ICO), defined as: no major complications, no reoperations, and reaching MCID for ODI. Surgical Invasiveness (SI) was normalized to a scale of 0-100 using the SI range. Thresholds for invasiveness and achieving ICO were found through conditional inference tree (CIT) analysis.
RESULT(S): A total of 381 ASD patients (59.3+/-15yrs, 26.9+/- kg/m2, CCI: 1.52+/-1.6, FI: 3.09+/-1.6) were included and underwent surgery (11.6+/-4 lvls fused, EBL: 1522+/-1275 mL, op time: 337+/-124 min, LOS: 7.3+/-3.9 days), with 62.2% having a posterior-only approach, 36.5% combined approach, 46% having a decompression and 65% an osteotomy. By deformity severity: 60% Low-Mod, 40% Severe, while frailty assessment was 49% NF, and 51% F. This categorized the patients into deformity/frailty groups as follows: 35% NF Low, 13% NF Sev, 22% F Low, 25% F Sev. Patients had a significantly different degree of SI: 35 NF Low/Mod, 38 F Low/mod, 48 NF Sev, 50 F Sev (p<0.001). CIT analysis found NF Sev patients had a higher likelihood of reaching ICO with an SI below 40 (OR: 3.6, 95% CI: 1.1-12.1, p=.037), and F Sev with a SI below 30 (OR: 4.6, 95% CI: 1.7-12.6, p=.003). Low/mod groups revealed no significant association between invasiveness and achieving ICO.
CONCLUSION(S): Analysis of increasing surgical invasiveness in patients stratified by frailty and baseline deformity showed frail severely deformed patients, compared with non-frail severely deformed patients, had a lower invasiveness threshold above which there was a higher risk of major complications, reoperations and failure to reach clinically important improvement in ODI. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Prior studies assessed the association between underlying neurological condition and worse outcomes following spinal surgery with recent emphasis of self-reported loss of balance (Imbalance) by Uribe et al. PURPOSE: To investigate if patients with self-reported loss of balance have poorer outcomes following adult spinal deformity (ASD) surgery. STUDY DESIGN/SETTING: Retrospective review of prospectively collected database. PATIENT SAMPLE: ASD patients with baseline and 2-year radiographic and patient-reported outcome measure (PROM) data were included. OUTCOME MEASURES: Demographics, radiographic outcomes, complications, and PROM were compared from baseline to 2-year follow up.
METHOD(S): Patients undergoing a long spinal fusion with no prior history of spine surgery were retained. Patients were grouped according to imbalance and unsteady gait. The groups were propensity matched by age, PI-LL, and surgical invasiveness score. Demographics, radiographic, complications and PROM were compared from baseline to 2-year post-op.
RESULT(S): A total of 212 patients were reported (106 patients in each group). The mean age (64 vs 63 years), BMI (27.2 vs 27.0 kg/m2), and gender (76% vs 87% female) were not significantly different for patients with imbalance and without imbalance respectively (all p >0.05). Patients in the imbalance group had a higher Frailty Index Score compared to patients without imbalance (3.74 vs 2.33, p <0.001). At baseline, the sagittal profile for both groups were comparable with regard to PT, PI-LL, and SVA. Patients with loss of balance had a significantly lower thoracic Cobb angle (25.27degree vs 37.45degree, p <0.001) and lumbar Cobb angle (37.03degree vs 45.53degree, p=0.004), although the global coronal alignment was similar (imbalance:41.51 mm vs 34.25 mm, p=0.155). Patients with imbalance had worse PROM measures, including ODI (45.15 vs 36.62), SF-36 Mental Component Score (44.04 vs 51.76), SF-36 Physical Component Score (30.17 vs 35.10), and SRS-22 Mental domain score (3.28 vs 3.80) (p <0.001 for all). Postoperatively, patients with imbalance had less PT correction (-1.45degree vs -3.60degree, p=0.039) for a comparable correction in their PI-LL (-11.93degree vs-15.08degree, p=0.144) by 2-year follow-up. Both groups demonstrated similar improvements in their coronal plane deformity. Imbalance patients had higher rates of radiographic PJK at 2-year follow-up (26.4% vs 14.2%, p=0.026). Furthermore, patients with reported imbalance have significantly higher rate of implant related complications (47.2% vs 34.0%, p=0.05). After controlling for age, baseline sagittal parameters, PI-LL correction and Charlson Comorbidity Index, patients with imbalance had 2.2 times increased odds of sustaining PJK by 2 years.
CONCLUSION(S): Patients with a self-reported loss of balance and unsteady gait have significantly worse baseline frailty and PROMs, represented by poorer mental health and physical function. Although those patients had higher rates of PJK and implant-related complications, surgical intervention significantly improved their quality of life. Despite the improvement, they remained with lower PROMs by 2-year follow-up. Therefore, in the clinic setting and with limited institutional access to Frailty scores, asking patients if they have loss of balance or unsteady gait is a simple yet powerful question which may trigger their preoperative risk stratification and optimization. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: It is imperative to determine which factors have greater implications on postoperative outcomes, which can afford tailored treatment plans for adult spinal deformity (ASD) patients. PURPOSE: To determine the discriminative ability of commonly used indices to predict adverse outcomes after corrective surgery for adult spinal deformity. STUDY DESIGN/SETTING: Retrospective cohort. PATIENT SAMPLE: This study included 9,763 patients. OUTCOME MEASURES: Perioperative complications.
METHOD(S): ASD patients from the National Surgical Quality Improvement Program (NSQIP) 2005-2015 were included. Logistic regression analysis determined significant odds ratios among complications between the following indices and demographics: Passias et al modified frailty index score for ASD (mFI-ASD), the modified Charlson Comorbidity Index (mCCI), ASA classification score, age and body mass index (BMI). Using multivariate analysis, indices and demographics that demonstrated significance for predicting complications were identified. CIT run forest analysis generated an index threshold value for all complications tested.
RESULT(S): Included: 9,763 ASD patients. At least 4 of the 5 risk indices were significant for the following complications: any type, major, cardiac, infection and death. None of the indices correlated with reoperation or readmission. The mFI-ASD demonstrated the highest odds ratio (OR) for all complications (p <.001), followed by ASA status. Modified CCI also correlated with a higher OR for all five complications, compared to age and BMI. An index threshold value for each complication was determined by CIT run forest analysis. Analysis of threshold values showed mFI had the highest ORs for any complication (OR: 3.50) as well as infection (OR: 2.53). ASA status, on the other hand, had the highest ORs for major complications (OR: 2.93), cardiac complications (OR: 4.09) and death (OR: 10.18).
CONCLUSION(S): The modified FI-ASD demonstrated superiority in predicting adverse postoperative outcomes, compared to various commonly used indices and patient characteristics. These findings are important as it allows spine surgeons to appropriately counsel their patients preoperatively. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Several studies have suggested that Hounsfield units (HU) in the spine are associated with increased complications for adult spinal deformity (ASD) patients. PURPOSE: The aim of this study is to assess whether there exists a threshold for HU that is associated with increased blood loss following ASD surgery. We hypothesize that HU below thresholds on spinal CT are predictive of increased blood loss during surgery and implant complications within 90 days after surgery for ASD. STUDY DESIGN/SETTING: Retrospective analysis. PATIENT SAMPLE: ASD patients who had HU measured in the spine were identified from a multicenter database. OUTCOME MEASURES: High Intraoperative blood loss and implant complications within 90 days of surgery.
METHOD(S): HU at L1, upper instrumented vertebrae (UIV) and total averages were assessed. Threshold linear regression with Bayesian information criteria was utilized to identify optimal cut-offs for predicting high blood loss (>2100mL, top 25% by volume) or any implant complications within 90 days. Implant complications included loosening, breakage and dislocation of rods or screws. Multivariable logistic regression was utilized controlling for age, gender, comorbidity, osteotomy and levels fused.
RESULT(S): Of 527 patients included, the mean age was 61+/-14. Mean L1 HU was 154.59+/-87, UIV HU was 175.1+/-304, and total average HU was 165+/-168. There were 59 patients with high blood loss (mean 5,026+/-233ml) and 467 with low blood loss (1,331+/-39.5ml). Threshold regression analysis identified that a cut-off of =140.33 was optimal for predicting high blood loss and =99.75 total average HU was optimal for predicting implant complications within 90 days of surgery. On multivariable analysis, L1 HU less than 140 was associated with 1.57x higher odds of high blood loss (P=0.032). Total average HU less than 100 was associated with a 3.6x higher odds of having an implant related failure within 90 days of surgery (P=0.035).
CONCLUSION(S): In this prospective multi-center study, Those with L1 HU=140 had a 1.52x higher odds of high blood loss. Patients with an average HUof =100 have 3.6x higher odds of implant related complication within 90 days of surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: A previous study by Pellise et al identified strong preoperative and surgical predictors of major complications. It is unknown which of these risk factors has the most significant impact on cost-effectiveness. PURPOSE: To assess the impact of previously established risk factors on the cost effectiveness of ASD surgery. STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: A total of 689 ASD patients. OUTCOME MEASURES: Quality adjusted life years (QALYs), utility gained, ODI, total cost.
METHOD(S): ASD patients with baseline (BL) and 2-year postoperative (2Y) data were included. Frailty score, sagittal deformity measures (SVA, PI-LL, T1 Sagittal Tilt), blood loss and surgical time were divided into tertiles, with the highest tertile being classified as high risk. Since some patients have multiple risk factors, they may be included in multiple groups. Descriptive analysis identified demographics, radiographic parameters and surgical factors. Published methods for cost was calculated using the PearlDiver database and CMS.gov definitions. Cost per QALY at 2Y was calculated for each risk factor.
RESULT(S): There were 422 patients included. Of the 381 patients with a risk factor, 77% were fused to the pelvis, 44% were highly frail, 56% had a high deformity, 34% had high EBL and 34% had high operative time. When analyzing BL scores, highly frail patients had the highest mean ODI and EQ-5D. After undergoing surgery, patients with a high EBL had the highest rate of SICU admissions, rate of any complications and rate of major complications. This translated to patients with high EBL having the lowest utility gained at 2Y. Interestingly, patients with high frailty had the highest rates of implant complications and pseudarthrosis resulting in the second highest major complication rates and total estimated cost. Despite this high estimated cost, however, patients with high frailty also achieved the highest utility gained at 2Y resulting in the best cost-utility at two years.
CONCLUSION(S): Despite having higher rates of implant failures, pseudarthrosis, and major complications, highly frail patients managed to generate the highest utility gained and best cost-effectiveness, while higher blood loss had higher rates of complications as well, but demonstrated the lowest utility gained and cost-utility. Therefore, spine surgeons should limit intraoperative risk factors, such as blood loss and operative time, which would minimize postoperative complications and improve overall cost-effectiveness during correction of adult spinal deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Surgical correction of cervical deformity is a proven treatment option that provides functional restoration and pain relief. It is unclear whether patient outcomes and costs of the procedure are influenced by the time between initial symptom onset and definitive surgical intervention. This study sought to determine how long nonoperative treatment should be exhausted prior to offering surgery for cervical deformity. PURPOSE: To identify whether delayed procedures influence patients' ability to recover and cervical deforminty corrective surgery cost effectiveness. STUDY DESIGN/SETTING: Retrospective cohort. PATIENT SAMPLE: This study included 290 cervical deformity patients. OUTCOME MEASURES: Delayed surgical intervention, recovery kinetics, cost effectiveness.
METHOD(S): Cervical deformity patients with baseline (BL) and two-year (2Y) follow-up data were included. Patients were stratified by time to surgery following the onset of their neck pain: >5 years=Delayed; <5 years=not Delayed. Normalized HRQL scores at BL and follow-up intervals (3M, 6M, 1Y, 2Y) were generated. Normalized HRQLs were plotted and area under the curve was calculated, generating one number describing overall recovery (Integrated Health State [IHS]). Cost was calculated using the PearlDiver database, which represents national average Medicare cost. Cost per Quality-Adjusted Life Year (QALY) at 2Y was calculated. Multivariable regression analysis assessed the impact of Delayed surgery on patient outcomes and cost.
RESULT(S): A total of 123 patients were included (54 Delayed, 69 not Delayed). Demographic and surgical characteristics were similar between groups (p > 0.05). Normalized HRQLs showed that Delayed patients exhibit worse NDI and NRS Neck at 2Y follow-up, both p 0.05. Utility gained at 2Y follow-up was 0.172 for Delayed and 0.2847 for not Delayed. This translated to QALY gained at 2Y of 0.334 for Delayed and 0.553 for not Delayed, p 0.05. Multivariable analysis found Delayed patients were less likely to gain utility (OR 0.125 [CI 0.019-0.840]) and QALYs (OR 0.343 [CI 0.129-0.914]) at 2Y postoperatively, both p< 0.05.
CONCLUSION(S): Patients who had a 5-year or greater delay to surgery from the onset of neck pain had more significant postoperative neck disability. Cost by procedure and cost-effectiveness when stratified by time to surgery following enrollment were comparable. While both patient cohorts had postop improvement, patients without delay had greater utility gained and quality adjusted life years at 2-year follow-up. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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OBJECTIVE:Revision surgery is often necessary for adult spinal deformity (ASD) patients. Satisfaction with management is an important component of health-related quality of life. The authors hypothesized that patients who underwent multiple revision surgeries following ASD correction would exhibit lower self-reported satisfaction scores. METHODS:This was a retrospective cohort study of 668 patients who underwent ASD surgery and were eligible for a minimum 2-year follow-up. Visits were stratified by occurrence prior to the index surgery (period 0), after the index surgery only (period 1), after the first revision only (period 2), and after the second revision only (period 3). Patients were further stratified by prior spine surgery before their index surgery. Scoliosis Research Society-22 (SRS-22r) health-related quality-of-life satisfaction subscore and total satisfaction scores were evaluated at all periods using multiple linear regression and adjustment for age, sex, and Charlson Comorbidity Index. RESULTS:In total, 46.6% of the study patients had undergone prior spine surgery before their index surgery. The overall revision rate was 21.3%. Among patients with no spine surgery prior to the index surgery, SRS-22r satisfaction scores increased from period 0 to 1 (from 2.8 to 4.3, p < 0.0001), decreased after one revision from period 1 to 2 (4.3 to 3.9, p = 0.0004), and decreased further after a second revision from period 2 to 3 (3.9 to 3.3, p = 0.0437). Among patients with spine surgery prior to the index procedure, SRS-22r satisfaction increased from period 0 to 1 (2.8 to 4.2, p < 0.0001) and decreased from period 1 to 2 (4.2 to 3.8, p = 0.0011). No differences in follow-up time from last surgery were observed (all p > 0.3). Among patients with multiple revisions, 40% experienced rod fracture, 40% proximal junctional kyphosis, and 33% pseudarthrosis. CONCLUSIONS:Among patients undergoing ASD surgery, revision surgery is associated with decreased satisfaction, and multiple revisions are associated with additive detriment to satisfaction among patients initially undergoing primary surgery. These findings have direct implications for preoperative patient counseling and establishment of postoperative expectations.

BACKGROUND:There is limited research regarding the association between the mFI-5 and postoperative complications among adult spinal deformity (ASD) patients. METHODS:Using the National Surgical Quality Improvement Project (NSQIP) database, patients with Current Procedural Terminology (CPT) codes for > 7-level fusion or < 7-level fusion with International Classification of Diseases, Ninth Revision (ICD-9) codes for ASD were identified between 2008 and 2016. Univariate analyses with post-hoc Bonferroni correction for demographics and preoperative factors were performed. Logistic regression assessed associations between mFI-5 scores and 30-day post-operative outcomes. RESULTS:2,120 patients met criteria. Patients with an mFI-5 score of 4 or 5 were excluded, given there were<20 patients with those scores. Patients with mFI-5 scores of 1 and 2 had increased 30-day rates of pneumonia (3.5 % and 4.3 % vs 1.6 %), unplanned postoperative ventilation for > 48 h (3.1 % and 4.3 % vs 0.9 %), and UTIs (4.4 % and 7.4 % vs 2.0 %) than patients with a score of 0 (all, p < 0.05). Logistic regression revealed that compared to an mFI-5 of 0, a score of 1 was an independent predictor of 30-day reoperations (OR = 1.4; 95 % CI 1.1-18). A score of 2 was an independent predictor of overall (OR = 2.4; 95 % CI 1.4-4.1) and related (OR = 2.2; 95 % CI 1.2-4.1) 30-day readmissions. A score of 3 was not predictive of any adverse outcome. CONCLUSION/CONCLUSIONS:The mFI-5 score predicted complications and postoperative events in the ASD population. The mFI-5 may effectively predict 30-day readmissions. Further research is needed to identify the benefits and predictive value of mFI-5 as a risk assessment tool.

BACKGROUND:The International Spine Study Group (ISSG) and the European Spine Study Group (ESSG) developed an adult spinal deformity (ASD) risk calculator based on one of the most granular, prospective ASD databases. The calculator utilizes preoperative radiographic, surgical, and patient-specific variables to predict patient-reported outcomes and complication rates at 2 years. Our aim was to assess the ISSG-ESSG risk calculator's usability in a single-institution ASD population. METHODS:tests. Each F patient was inputted into the ESSG risk calculator to identify individual predictive rates for postoperative 2-year health-related quality of life questions (HRQL) outcomes and major complications. These calculated predicted outcomes were analyzed against those identified from the ASD database in order to validate the calculator's predictability via Brier scores. A score closer to 1 meant the ISSG-ESSG calculator was not predictive of that specific outcome. A score closer to 0 meant the ISSG-ESSG calculator was a predictive tool for that factor. RESULTS:, 0.95 ± 1.3 Charlson Comorbidity Index). Of those patients, 7.8% were frail. Fifty percent of frail patients received an interbody fusion, 58.3% received a decompression, and 79.2% underwent osteotomy. Surgical details were as follows: mean operative time was 342.9 ± 94.3 minutes, mean estimated blood loss was 2131.82 ± 1011 mL, and average length of stay was 7.12 ± 2.5 days. The ISSG-ESSG calculator predicted the likelihood of improvement for the following HRQL's: Oswestry Disability Index (ODI) (86%), Scoliosis Research Society (SRS)-22 mental health (71.1%), SRS-22 total (87.6%), and major complication (53.4%). The single institution had lower percentages of improvement in ODI (24.6%), SRS-22 mental health (21.3%), SRS-22 total (25.1%), and lower presence of major complication (34.8%). The calculated Brier scores identified the calculator's predictability for each factor was as follows: ODI (0.24), SRS-22 mental health (0.21), SRS-22 total (0.25), and major complication (0.28). CONCLUSIONS:All of the variables had low Brier scores, indicating that the ISSG-ESSG calculator can be used as a predictive tool for ASD frail patients. LEVEL OF EVIDENCE: 3/METHODS/:

Prediction of blood transfusion after adult spinal deformity (ASD) surgery can identify at-risk patients and potentially reduce its utilization and the complications associated with it. The use of artificial neural networks (ANNs) offers the potential for high predictive capability. A total of 1173 patients who underwent surgery for ASD were identified in the 2017-2019 NSQIP databases. The data were split into 70% training and 30% testing cohorts. Eighteen patient and operative variables were used. The outcome variable was receiving RBC transfusion intraoperatively or within 72 h after surgery. The model was assessed by its sensitivity, positive predictive value, F1-score, accuracy (ACC), and area under the curve (AUROC). Average patient age was 56 years and 63% were female. Pelvic fixation was performed in 21.3% of patients and three-column osteotomies in 19.5% of cases. The transfusion rate was 50.0% (586/1173 patients). The best model showed an overall ACC of 81% and 77% on the training and testing data, respectively. On the testing data, the sensitivity was 80%, the positive predictive value 76%, and the F1-score was 78%. The AUROC was 0.84. ANNs may allow the identification of at-risk patients, potentially decrease the risk of transfusion via strategic planning, and improve resource allocation.