Faculty Bibliography

BACKGROUND CONTEXT: Hospital acquired conditions (HACs) were established in the Affordable Care Act, and are defined as reasonably preventable complications that are nonreimbursable. In high risk patient populations for HACs, such as frail surgical spine patients, preoperative evaluation should consider modifiable factors. PURPOSE: To identify if optimizing the modifiable factors in the frailty index reduce the risk of developing HACs in population of surgical spine patients. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: This study included 196,523 elective spine surgery patients in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). OUTCOME MEASURES: Modifiable patient frailty factors: hypertension and diabetes mellitus; rates of HACs, superficial or deep surgical site infection (SSI), deep venous thromboembolism (VTE) and urinary tract infection (UTI), across frailty scores.
METHOD(S): Patients >18 years who underwent elective spine surgery were identified in ACS-NSQIP database from 2005-2016. HACs identified: SSI, VTE, and UTI. Patient frailty was assessed utilizing the modified NSQIP 5-factor frailty index. The modified frailty score (mFI-5) is assessed on a scale between 0 and 1 (no frailty [NF] <0.3, mild frailty [MF] 0.3-0.5, severe frailty [SF] >0.5). Descriptive analysis quantified rates of patient characteristics, operative details, and HAC prevalence. Stepwise linear regression models determined significant predictors of baseline frailty using controllable patient factors. HACs were compared between 'optimized' and 'non-optimized' frailty status in the cohort. Level of significance was set to P<0.05.
RESULT(S): A total of 196,523 patients (57+/-14.2 years, 30.4 kg/m², 48%F) met inclusion criteria. Overall, 5,720 (2.9%) of patients developed an HAC, the most common was an SSI (1.3%), followed by UTI (1.1%). When stratified by the mFI-5 frailty severity groups at baseline, 83.6% of patients were categorized NF, 15.1% MF and 1.3% SF. Within the frailty severity groups, prevalence of overall HACs increased significantly (NF: 2.64%, MF: 4.17%, 5.93%, p<0.001). Rates of all individual postoperative HACs assessed also increased with greater baseline frailty severity: SSI (NF: 1.14%, MF: 1.93%, SF: 2.39%, p<0.001), UTI (NF: 0.91%, MF: 1.66%, SF: 2.85%, p<0.001), VTE (NF: 0.68%, MF: 0.80%, SF: 1.16%, p=0.002). Stepwise linear regression models determined that diabetes mellitus (beta = 0.493) and hypertension (beta = 0.679) were the most significant predictors for increased baseline frailty by way of the mFI-5 NSQIP index (Final model: R2= 0.897). Of total patients, 47.2% had the optimal modifiable frailty factors (no history of diabetes or hypertension). The optimal frailty patients had significantly less overall incidence of SSI (2.03% vs 2.5%, p<0.001), UTI (0.65% vs 1.4%, p<0.001), DVT (0.56% vs 0.84%, p<0.001), and any overall HAC (2.18% vs 3.56%, p<0.001).
CONCLUSION(S): Stepwise linear regression models determined that hypertension and diabetes account for 89.7% of variance in baseline mFI-5 score. Patients with these optimal controllable factors had reduced incidence of all hospital acquired conditions. In order to optimize hospital resources and treatment outcomes, physicians and patients should be aware of the modifiable factors that contribute to a patient's frailty that can ultimately impact acquiring HACs. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: The International Spine Study Group (ISSG) and the European Spine Study Group (ESSG) developed an adult spinal deformity (ASD) specific risk calculator based on the largest and most granular, prospective ASD database. The calculators utilize preoperative radiographic, surgical, and patient-specific variables in order to predict patient-reported outcomes and complication rates at 2 years. PURPOSE: Assess the ISSG-ESSG risk calculator usability in a single institution ASD population. STUDY DESIGN/SETTING: Retrospective cohort study- single surgeon institution. PATIENT SAMPLE: ASD pts: A total of 631 patients undergoing surgery for adult spinal deformity. OUTCOME MEASURES: Improvement from BL SRS-22 [Pain, Function, total], major complications, Oswestry Disability Index (ODI).
METHOD(S): ASD pts were isolated in the single-center ASD Database 2013-2020. Frail pts were isolated (Frail[F] 0.3>0.5). Basic demographics were assessed for these F pts via chi-squared and t-tests. Each F patient was inputted into the ESSG risk calculator to identify individual predictive rates for postoperative 2-year HRQL outcomes as well as major complications. These calculated predicted outcomes were analyzed against those identified from the ASD database in order to validate the calculator predictability in a single center institution via Brier scores. Having a score closer to 1 means the EESG calculator is not predictive of that specific outcome. A score closer to 0 meant the EESG calculator was a predictive tool for that factor.
RESULT(S): A total of 631 ASD pts were isolated (55.8;16.8yrs, 26.68kg/m², 0.95+/-1.3CCI). Of these patients, 7.8% were frail. Fifty percent of frail pts received an interbody fusion, 58.3% received a decompression, and 79.2% had an osteotomy. Surgical details: mean operative time 342.9+/-94.3minutes, mean estimated blood loss 2131.82+/-1011mL, and an average length of stay 7.12+/-2.5days. The EESG calculator predicted the likelihood of improvement for the following HRQL's ODI(86%), SRS-22 Mental Health (71.1%), SRS-22 Total (87.6%), 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: ODI (0.24), SRS-22 Mental Health (0.21), SRS-22 Total (0.25), major complication (0.28).
CONCLUSION(S): The newly developed ESSG-ISSG risk-assessment tool has a wide application in single institutions as it accurately predicts 2-year outcomes for various SRS-22 questionnaires and development of major complications. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Frailty is a baseline measure of disability that transcends age alone and has been determined a strong predictor of outcomes following adult spinal deformity (ASD) surgery. This postop impact calls for investigation of unique adjustment of Global Alignment and Proportion (GAP) scores accounting for frailty. This adjustment in spinal proportion may help surgical planning for individualized, optimal postop outcomes. PURPOSE: Modify the GAP score with frailty to optimize outcomes in surgical ASD patients. STUDY DESIGN/SETTING: Retrospective review of a single-surgeon comprehensive ASD database PATIENT SAMPLE: A total of 140 ASD patients OUTCOME MEASURES: Frailty-adjusted GAP scores; Health Related Quality of Life scores (HRQLs): ODI, SRS-22 METHODS: Surgical ASD patients (SVA>=5cm, PT>=25degree, or TK >=60degree, >3 levels fused) >=18 years old with available baseline (BL) radiographic data were isolated in the single-center Comprehensive Spine Quality Database (Quality). Patients were dichotomized by the ASD frailty index, F (Not Frail, Frail). Linear regression analysis established radiographic equations for frailty-adjusted GAP Scores at baseline and 2-years involving relative pelvic version, relative lumbar lordosis, lordosis distribution index, relative spinopelvic alignment, and an age factor to formulate a sagittal plane score. Patients were restratified into frailty-adjusted proportionality groups: Proportional (<5.8), Moderately Disproportional (MD) (5.8-7), Severely Disproportional (SD) (>7). Frailty-adjusted GAP proportionality at 2-years were compared to adjusted-BL to determine whether patients improved, deteriorated or remained the same in their spine proportion.
RESULT(S): A total of 140 patients were included (55.5+/-16.4 yrs, 77.5% female, 25.2+/-4.7 kg/m2). BL frailty: 32.8% not frail, 67.2% frail. Primary analyses demonstrated correlation between BL frailty score and BL and 2-year GAP scores(P<0.001). Linear regression analysis(p<0.001) developed a frailty-adjusted GAP threshold equation: 4.4 + 0.93*(frailty score). Adjusted-baseline scores were taken and re-stratified based distribution and placed 26.4% of patients in Proportional, 26.6% MD, and 44% SD. BL adjusted GAP scores by frailty group: 5.3 Not Frail, 7.5 Frail; p<0.001. At 2-years, GAP scores were grouped into the frailty-adjusted proportionality groups: 66.2% Proportional, 10.8% MD, and 23.1% SD. Patients who were 2-year MD/SD underwent significantly more reoperations (>33.5%) compared to Proportional (12.8%), p=0.015. SD 2-year patients developed increased PJK at the 1-year mark (40%, Proportional: 13.9%, MD:7.1%, p=0.003), as well as had worse 2-year ODI and SRS-22 satisfaction scores(p<0.050). 47.5% improved in GAP (63.4% of frail patients), 12.3% deteriorated, and 40.2% remained in the same proportionality group at 2-year follow up.
CONCLUSION(S): Significant associations exist between frailty and spinal proportion. By adjusting the GAP proportionality groups accounting for baseline frailty contributed to improved outcomes and minimized reoperations. The adjusted GAP groups appeal for less rigorous spine proportion goals in severely frail patients. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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Study Design/UNASSIGNED:Retrospective review of single institution. Objective/UNASSIGNED:To assess the relationship between Patient-Reported Outcomes Measurement Information System (PROMIS) and Oswestry Disability Index (ODI) scores in thoracolumbar patients. Methods/UNASSIGNED:Included: Patients ≥18 years with a thoracolumbar spine condition (spinal stenosis, disc herniation, low back pain, disc degeneration, spondylolysis). Bivariate correlations assessed the linear relationships between ODI and PROMIS (Physical Function, Pain Intensity, and Pain Interference). Correlation cutoffs assessed patients with high and low correlation between ODI and PROMIS. Linear regression predicted the relationship of ODI to PROMIS. Results/UNASSIGNED:= 0.499) of the variance in Pain Intensity score. Conclusions/UNASSIGNED:There is a large amount of variability with PROMIS that cannot be accounted for with ODI. ODI questions regarding walking, social life, and lifting ability correlate strongly with PROMIS while sitting, standing, and sleeping do not. These results reinforce the utility of PROMIS as a valid assessment for low back disability, while indicating the need for further evaluation of the factors responsible for variation between PROMIS and ODI.

BACKGROUND CONTEXT/BACKGROUND:Obesity has risen to epidemic proportions within the United States. As the rates of obesity have increased, so has its prevalence among patients undergoing adult spinal deformity (ASD) surgery. The effect of obesity on the cost efficiency of corrective procedures for ASD has not been effectively evaluated. PURPOSE/OBJECTIVE:To investigate differences in cost efficiency of ASD surgery for patients stratified by body mass index (BMI). STUDY DESIGN/SETTING/METHODS:Retrospective review of a single center ASD database. PATIENT SAMPLE/METHODS:505 ASD patients OUTCOME MEASURES: Complications, revisions, costs, EuroQol-5D (EQ5D), quality adjusted life years (QALYS), cost per QALY. METHODS:ASD patients (scoliosis≥20°, SVA≥5cm, PT≥25°, or TK ≥60°) ≥18, undergoing ≥4 level fusions were included. Patients were stratified into NIH-defined obesity groups based on their preoperative BMI: underweight 18.5< (U), normal 18.5-24.9 (N), overweight 25.0-29.9 (O), obese I 30.0-34.9 (OI), obese II 35.0-39.9 (OII), and obesity class III 40.0 + (OIII). Total surgery costs for each ASD obesity group were calculated. Costs were calculated using the PearlDiver database, which reflects both private insurance and Medicare reimbursement claims. Overall complications (CC) and major complications (MCC) were assessed according to CMS. DEFINITIONS/BACKGROUND:QALYs and cost per QALY for obesity groups were calculated using an annual 3% discount up to life expectancy (78.7 years). RESULTS:In all, 505 patients met inclusion criteria. Baseline demographics and surgical details were: age 60.8 ± 14.8, 67.6% female, BMI 28.8 ± 7.30, 81.0% posterior approach, 18% combined approach, 10.1 ± 4.2 levels fused, op time 441.2 ± 146.1 minutes, EBL 1903.8 ± 1594.7 cc, LOS 8.7 ± 10.7 days. There were 17 U, 154 N patients, 151 O patients, 100 OI, 51 OII, and 32 OIII patients. Revision rates by obesity group were: 0% U, 3% N patients, 3% O patients, 5% OI, 4% OII, and 6% for OIII patients. The total surgery costs by obesity group were: $48,757.86 U, $49,688.52 N, $47,219.93 O, $50,467.66 OI, $51,189.47 OII, and $53,855.79 OIII. In an analysis of patients with baseline and 1Y EQ5D follow up, the cost per QALY by obesity group was: $153,737.78 U, $229,222.37 N, $290,361.68 O, $493,588.47 OI, $327,876.21 OII, and $171,680.00 OIII. If that benefit was sustained to life expectancy, the cost per QALY was $8,588.70 U, $12,805.72 N, $16,221.32 O, $27,574.77 OI, $18,317.11 OII, and $9,591.06 for OIII. CONCLUSIONS:Among adult spinal deformity patients, those with BMIs in the obesity I, obesity II, or obesity class III range had more expensive total surgery costs. When assessing 1 year cost per quality adjusted life year, obese patients had costs 32% higher than non-obese patients ($224,440.61 vs. $331,048.23). Further research is warranted on the utility of optimizing modifiable preoperative health factors for patients undergoing corrective adult spinal deformity surgery.

Metabolic syndrome is a clustering of clinical findings defined in the literature including hypertension, high glucose, abdominal obesity, high triglyceride, and low high-density lipoprotein cholesterol levels. The purpose of this study was to assess perioperative outcomes in patients undergoing spine fusion surgery with (MetS) and without (no-MetS) a history of metabolic syndrome. Included: Patients ≥18 yrs old undergoing spine fusion procedures diagnosed with MetS components with BL and 1-year follow-up were isolated in a single-center database. Patients in the two groups were propensity score matched for levels fused. 250 spine fusion patients (58 yrs, 52.2%F, 39.0 kg/m²) with an average CCI of 1.92 were analyzed. 125 patients were classified with MetS (60.2 yrs, 52%F, CCI: 3.2). MetS patients were significantly older (p = 0.012). MetS patients underwent significantly more open (Met-S: 78.4% vs No-MetS: 45.6%, p < 0.001) and posterior approached procedures (Met-S: 60.8% vs No-MetS: 47.2%, p = 0.031). Mean operative time: 272.4 ± 150 min (MetS: 288.1 min vs. no-MetS: 259.7; p = 0.089). Average length of stay: 4.6 days (MetS: 5.27 vs no-MetS: 3.95; p = 0.095). MetS patients had more post-operative complications (29.6% vs. 18.4%; p = 0.038), specifically neuro (6.4% vs 2.4%), pulmonary (4% vs. 1.6%), and urinary (4.8% vs 2.4%) complications. Binary logistic regression analyses found that MetS was an independent risk factor for post-operative complications (OR: 1.865 [1.030-3.375], p = 0.040). With longer surgeries and greater open-exposure types, MetS patients were at greater risk for complications, despite controlling for total number of levels fused. Surgeons should be aware of the increased threat to spine surgery patients with metabolic syndrome in order to optimize surgical decision-making.

Background/UNASSIGNED:Multilevel fusions and complex osteotomies to restore global alignment in adult spinal deformity (ASD) surgery can lead to increased operative time and blood loss. In this regard, we assessed factors predictive of perioperative blood product transfusion in patients undergoing long posterior spinal fusion for ASD. Methods/UNASSIGNED:A single-institution retrospective review was conducted on 909 patients with ASD, age > 18 years, who underwent surgery for ASD with greater than 4 levels fused. Using conditional inference tree analysis, a machine learning methodology, we sought to predict the combination of variables that best predicted increased risk for intraoperative percent blood volume lost and perioperative blood product transfusion. Results/UNASSIGNED: = .046). Conclusions/UNASSIGNED:Using a supervised learning technique, this study demonstrates that greater than 13 levels fused, ASA score > 1, 3-column osteotomy, and pelvic fixation are consistent risk factors for increased intraoperative percent blood volume lost and perioperative RBC transfusion. The addition of having a preoperative hemoglobin < 13.6 g/dL or undergoing a posterior column osteotomy conferred the highest risk for intraoperative blood loss. This information can assist spinal deformity surgeons in identifying at-risk individuals and allocating healthcare resources. Level of Evidence/UNASSIGNED:3.

OBJECTIVE:In the setting of a previous proximal fusion, an asymmetric 3-column osteotomy (3CO) can provide tremendous deformity correction. Our goal was to evaluate outcomes and complications of asymmetric 3CO through the proximal fusion mass, for coronal malalignment in patients with previous long thoracic fusion for adolescent idiopathic scoliosis. METHODS:This was a retrospective case series. Thirteen individuals with a history of a long thoracic fusion underwent asymmetric 3CO for persistent coronal malalignment. Clinical chart review was conducted to determine perioperative complications and radiographs evaluated for alignment. RESULTS:Thirteen patients (age: 57.8 ± 12.2 years; 0 male, 13 female) completed a mean follow-up of 42.4 months. There was significant improvement in coronal and sagittal alignment, and pelvic incidence-lumbar lordosis postoperatively (P < 0.05). One patient developed lower-extremity weakness requiring revision decompression 72 hours postoperatively; the weakness subsequently resolved. One patient had a foot drop postoperatively. At final follow-up, 12 of 13 patients had grade 1 fusion at the osteotomy site; 1 patient had a grade 2 fusion. None of the patients developed a pseudarthrosis, or superficial or deep infections. CONCLUSIONS:Patients with a history of previous thoracic fusion for adolescent idiopathic scoliosis and coronal malalignment may develop painful degeneration of the segments caudal to the fusion as adults. In this setting, extension of fusion to the sacropelvis alone may worsen the patient's coronal alignment. An asymmetric 3CO may be considered at the proximal fusion mass to achieve realignment objectives, with an acceptable complication rate and an expected improvement in outcomes.

BACKGROUND CONTEXT/BACKGROUND:ASD (Adult spinal deformity) surgery often entails complex osteotomies and realignment procedures, particularly in the setting of rigid deformities. While previous studies have established the efficacy of tranexamic acid (TXA), data evaluating the widely variable dosing regimens remains sparse. PURPOSE/OBJECTIVE:To improve understanding of blood loss and transfusion requirements for low-dose and high-dose TXA regimens for adult spinal deformity (ASD) surgery. STUDY DESIGN/SETTING/METHODS:This is a retrospective cohort study of 318 ASD patients who received TXA. Outcome measures include estimated blood loss (EBL), perioperative transfusion requirement, and complications. METHODS:A retrospective review was conducted on 318 ASD patients: 258 patients received a low-dose regimen of TXA (10 or 20 mg/kg loading dose with a 1 or 2 mg/kg/h maintenance dose) and 60 patients received a high-dose regimen of TXA (40 mg/kg loading dose with a 1 mg/kg/h maintenance dose, 30 mg/kg loading dose with a 10 mg/kg/h maintenance dose, or 50 mg/kg loading dose with a 5 mg/kg/h maintenance dose). RESULTS:Compared with the low-dose TXA group, the high-dose TXA group had significantly decreased EBL (1402 vs. 1793 mL, p=0.009), blood volume lost (30.3 vs. 39.4%, p=0.01), intraoperative packed red blood cell (pRBC) transfusion (0.9 vs 1.6 U, p<0.0001), and intraoperative platelet transfusion (0 versus 0.1 U, p<0.0001). High-dose TXA was predictive of 515 cc less EBL (p=0.002), 11.4% less blood volume lost (p=0.004), and 1 U pRBC less transfused intraoperatively (p<0.0001) than the low-dose TXA group. The high-dose TXA group had a higher incidence of postop atrial fibrillation (AF) (5 vs 0%, p<0.0001) and myocardial infarction (MI) (1.7 vs. 0%, p=0.04). CONCLUSIONS:Varying dosing regimens of TXA are utilized for ASD surgery, with a prevailing theme of dosing ambiguity. These data demonstrate that high-dose TXA is more effective than low-dose TXA in reducing blood loss and blood product transfusion requirement in ASD surgery. Importantly, rates of MI and postop AF were higher in the high-dose TXA group.

BACKGROUND CONTEXT: Persistent lumbopelvic malalignment following ASD-corrective surgery may impair quality of life and result in persistent pathologic compensation in the lower extremities. Patient-specific age- and BMI-adjusted alignment targets have been proposed to improve alignment outcomes; however, it is unclear whether reaching these postop targets reduces rates of pelvic nonresponse following surgery. PURPOSE: Assess the relationship between pelvic nonresponse to ASD-corrective surgery and persistent lower-extremity compensation. STUDY DESIGN/SETTING: Single center retrospective review. PATIENT SAMPLE: Fifty-eight ASD patients. OUTCOME MEASURES: Sagittal alignment.
METHOD(S): Included: surgical ASD patients with full-spine X-ray imaging at pre- and early postop follow-up (<1Y). Patients were grouped by postop improvement in PT, per SRS-Schwab Classification: those who did not improve (pelvic nonresponders, PNR), and those that did improve (pelvic responders, PR). Groups were propensity score matched for preop PT, and assessed for differences in demographics, surgical factors, and alignment (sagittal spinal and lower extremity) with means comparison tests. Rates of persistent postop lower extremity compensation (defined as no improvement in lower extremity alignment) were compared between groups. Subanalysis assessed the relationship between reaching postop age- and BMI-specific alignment targets and rates of pelvic nonresponse.
RESULT(S): Following propensity score matching, PNR (N=29) and PR (N=29) patients did not differ in age, sex, BMI or preop sagittal spinal alignment (all p>0.05); however, PNR patients presented with less knee flexion (9degree vs 14degree, p=0.043). Groups did not differ in levels fused (10.8 vs 10.8, p=0.974) or osteotomy (93% vs 92%, p=0.902). Postop, PNR patients had inferior lumbopelvic alignment in PT (30degree vs 17degree), PI-LL (17degree vs 3degree), and greater global malalignment for TPA (27degree vs 15degree, all p<0.001). For PNR patients, these changes in alignment were accompanied by greater compensatory anterior hip extension (53mm vs 31mm, p=0.021). PNR patients also showed greater pre- to postop increases in sacrofemoral angle (2degree vs -5degree), and smaller decreases in hip extension (-24mm vs -64mm), pelvic femoral angle (-1.4degree vs -3.8degree), and global sagittal angle (-3.5degree vs -8degree, all p<0.005), indicating persistent lower extremity compensation. PNR patients had higher rates of persistent postop lower extremity compensation for sacrofemoral angle (68% vs 25%), ankle flexion (64% vs 33%), and pelvic shift (28% vs 4%, all p<0.034). PNR and PR groups did not differ in rates of reaching age- and BMI specific ideal postop alignment for PT, SVA, TPA, or PI-LL (all p>0.05). For patients with severe preop SVA deformity, overcorrection relative to ideal postop PT targets was associated with lower rates of pelvic non-response (under: 12%, match: 18%, over: 71%, p<0.001). Lower rates of nonresponse were observed for patients with severe preop PT deformity overcorrected relative to ideal postop PI-LL (under: 0%, match: 30%, over: 70%, p=0.016).
CONCLUSION(S): Pelvic nonresponders following ASD-corrective surgery had higher rates of persistent compensatory action in the lower extremities. Patients with severe preop PT deformity who were surgically overcorrected with respect to ideal PI-LL had lower rates of postop pelvic nonresponse, indicating that for severely malalignmed patients, existing alignment targets may need to be adjusted to optimize alignment outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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