Multicenter Adult Spinal Deformity Database Research Articles

209. Global spinal deformity from the upper cervical perspective: what is “abnormal” in the upper cervical spine?

BACKGROUND CONTEXT Reciprocal changes in cervical alignment occur with incremental degrees of adult spinal deformity (ASD) severity, or across different sagittal morphotypes as described respectively by Schwab and Roussouly systems. The extent to which these systems relate changes in the upper cervical spine remains underexplored. PURPOSE To investigate quantitative anatomical relationships with regards to abnormal alignment in the upper cervical spine. STUDY DESIGN/SETTING Retrospective review of a prospective multicenter ASD database. PATIENT SAMPLE A total of 343 patients who met criteria for ASD. OUTCOME MEASURES Cervical alignment parameters (C2-C7 angle, C2 slope, McGregor's Slope, CBVA when available, segmental tilt), Ostrow Disability Index (ODI) METHODS Patients >18 years with ASD (scoliosis≥20°, SVA≥5cm, PT≥25°, or thoracic kyphosis ≥60°) and complete radiographic data at baseline (BL) & 1-year (1Y) were identified. Patients were grouped by BL PI and apex of LL into component types of the Roussouly classification system (Type 1: PI 65°). Patients were categorized by increasing severity of SRS-Schwab modifiers at BL (0, +, ++) and further grouped by anatomical malalignment, moving cranially (P: pelvic only; LP: lumbopelvic; TL: thoracolumbopelvic; C: subaxial & thoracolumbo-pelvic). Analysis of variance (ANOVA) tests assessed differences in BL upper cervical alignment parameters (C0-C2, C0 slope, McGregor's slope, CBVA) and ODI scores across Roussouly and Schwab modifier groups. RESULTS A total of 343 ASD patients were analyzed. Schwab modifiers at BL were as follows: SVA (0: 45.8%, +: 20.3%, ++: 33.9%), PI-LL (0: 42.3%, +: 20.7%, ++: 37.0%), PT (0: 38.6%, +: 36.2%, ++: 25.3%). By Roussouly classification, 4.2% were Type 1, 19.3% were Type 2, 43.1% were Type 3, and 33.3% were Type 4. Moving cranially up the spine, Group P (10.6%), Group LP (54.7%) and Group TL (8.5%) did not differ in C0-C2 angle, C0 slope, MGS or CBVA (all P>0.05). Group C (26.2%) had a significantly smaller C0-C2 angle, and more negative MGS, C0 slope, and CBVA than non-cervical groups. By Roussouly type, Type 1 trended slightly higher CBVA and MGS than types 2-4 without statistical significance (all P>0.05). No differences in CL, C0-C2, or C0S were found between Types 1-4 (all P>0.05). McGregor's slope (r=-0.131, P=0.015), CBVA (r=-0.473, P 34mm predicted a 1 unit(°) decrease in MGS (OR: 0.970 [0.948 – 0.993], p=0.010), while cSVA>51mm predicted a 1 unit increase in MGS (OR: 1.25[1.12-1.38], p CONCLUSIONS Our present study suggests that upper cervical alignment remains relatively stable through most broad variations of adult thoracolumbar deformity. Changes in SVA correlated most with upper cervical changes compared to other TL modifiers. Incremental trends in upper cervical alignment changes were observed as TL deformity extended cranially, with greatest variation in pts who also had subaxial malalignment. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

212. Giving patients the info they want: practical answers to FAQs for shared decision-making in ASD surgery

BACKGROUND CONTEXT The shared decision-making (SDM) process is an opportunity to deliver answers to frequently asked questions (FAQs) in adult spinal deformity (ASD) surgery. PURPOSE Our goal was to present a concise list of answers to these FAQs to aid in SDM counseling. 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 2008-2016. OUTCOME MEASURES Health related quality of life (HRQOL) outcome measures were collected such as Oswestry Disability Index (ODI), SF-36 PCS, and SF-36 MCS. METHODS Adult patients undergoing ≥ 5 level fusion with minimum 2-year follow up were included. We purposely included all deformity types (heterogeneity) to provide general applicability. We compiled a list of FAQs by patients undergoing ASD surgery and utilized a retrospective analysis to provide answers. All responses are reported as either means or reaching minimal clinically important difference (MCID) at the 2-year follow-up interval. RESULTS Out of 689 ASD patients eligible for 2-year follow-up, 521 (76%) had complete follow-up. The majority were female (77%) with mean age of 58.5 years and BMI of 27.5. Mean levels fused were 11.3 with 52% being primary vs 48% revision surgeries. Will my pain improve? Back (7.2 to 3.6) and leg (4.7 to 2.6) pain were both reduced by ∼50%. Will my activity level improve? A total of 63.9% reached MCID for SRS-22r activity. Will I feel better about myself? A total of 71.2% reached MCID for SRS-22r appearance. Is there a chance I'm worse? A total of 4.1% of patients were worse (ODI). What is the likelihood I have a complication? A total of 52.9% of patients have at least 1 complication and 29.6% have a major complication. Will I need another surgery? A total of 29.6% of patients have a reoperation within 2 years. Will I regret having surgery? A total of 32% would not choose the same treatment. Will I get a blood transfusion? A total of 79.1% of patients receive a blood transfusion. How long will I stay in the hospital? Study showed 9.9 days. Will I have to go to the ICU? A total of 79.1% of patients require an ICU stay. Will I be able to return to work? A total of 71% returned to full-time work at 2 years. Will I be taller after surgery? Yes, 1.4cm was the average CONCLUSIONS The above list provides concise, practical answers to FAQs encountered in the SDM process while counseling patients for ASD surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

P84. Predicting ASD surgeries that exceed Medicare allowable payment thresholds: a comparison of hospital costs to what the government will actually pay

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. METHODS 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 iEOC RESULTS 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 CONCLUSIONS 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 (iEOC FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

190. Preoperative opioid therapy poorly controls pain in nonrevision adult spinal deformity (ASD) and increases risk for chronic postoperative opioid usage

BACKGROUND CONTEXT Iatrogenic malalignment, nonunion and adjacent segment degeneration are established etiologies for pain in adult spinal deformity (ASD). However, reasons for pain among ASD patients with no prior history of surgery (nonrevision) are incompletely understood. Opioid therapy for pain is controversial and problematic. PURPOSE Compare pain scores in nonrevision ASD patients who preoperatively receive opioids vs no opioids and evaluate pain scores and risk for chronic opioid use following surgical treatment. It is hypothesized that preop opioid therapy poorly controls pain and increases risk for chronic postop opioid use compared to opioid nonusers in nonrevision ASD patients. STUDY DESIGN/SETTING Analysis of a prospective multicenter ASD database. PATIENT SAMPLE ASD patients with no history of prior spine surgery, enrolled into a prospective multicenter database and subsequently surgically treated for ASD. OUTCOME MEASURES Scoliosis Research Society-22r questionnaire (SRS-22r), SF-36, numeric rating scale (NRS) back and leg pain. METHODS ASD patients (age >18 years, no history of spine surgery), were enrolled into a prospective multicenter ASD database and evaluated for opioid use on SRS-22r questionnaire. Patients divided into preop opioid (OPIOID) vs nonopioid (NON) users, organized into SRS deformity types (thoracic, lumbar, double, sagittal and mixed), treated surgically for ASD and evaluated minimum 2 years postop. Pre- and postop demographic, radiographic, and pain values evaluated, and postop opioid usage compared. RESULTS Two hundred twenty-seven of 426 patients, (mean follow-up 3.3 years) were eligible for study and evaluated. Distribution of SRS deformity type for OPIOID vs NON was similar. Comparison of scoliosis patients (thoracic, lumbar or double deformities) demonstrated OPIOID (n=32) had similar preop age, BMI, smoking history, maximal scoliosis, SVA, and sagittal spinopelvic parameters as NON (n=95; p>0.05). However, OPIOID had greater preop NRS back pain (7.3 vs 6.1), leg pain (4.9 vs 3.1), and worse SF-36 bodily pain (31.8 vs 39.8) than NON (p 0.05). However, OPIOID had greater preop NRS back pain (7.8 vs 7.0), leg pain (5.8 vs. 3.8), and worse SF-36 bodily pain (29.3 vs. 35.6) than NON (p CONCLUSIONS Evaluation of 227 surgically treated nonrevision ASD patients demonstrated that despite having similar demographics, spinal deformity and similar surgery OPIOID reported greater preop pain scores, greater postop pain scores and had greater risk for opioid usage than NON. The relative risk of opioid usage at 2 years postop was 5.0 for preop daily users and 2.8 for preop weekly users compared to NON. Preop opioid therapy should be avoided in non-revision ASD. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

193. Comprehensive alignment planning (CAP) for adult spinal deformity (ASD) more effectively predicts surgical outcomes and proximal junctional kyphosis than previous classifications

BACKGROUND CONTEXT Several methodologies have been proposed to determine ideal adult spinal deformity (ASD) sagittal spinopelvic alignment, two of them being; (1) patient age adjusted alignment based on pelvic incidence-lumbar lordosis (PI-LL), and sagittal vertical alignment (SVA) and (2) global alignment and proportion (GAP) score (a calculator initially developed to assess proximal junctional kyhosis [PJK] risk). A recent study evaluating the ability of different methodologies to predict PJK highlighted GAP inability to effectively predict PJK outside the original GAP creation data set. PURPOSE Investigate a novel methodology (comprehensive alignment planing, or CAP) that utilizes a hybrid approach to assess ASD alignment by combining age adjusted alignment thresholds with concurrent alignment parameters. STUDY DESIGN/SETTING Retrospective review of a prospective ASD database. PATIENT SAMPLE Surgically treated ASD patients minimum 2-year follow-up. OUTCOME MEASURES Sagittal alignment, ODI, SF-36, SRS-22r, proximal junctional kyphosis/failure, CAP and GAP scores. METHODS Multicenter ASD database was evaluated for surgically treated ASD patients with (1) fusion with a minimum of 5 levels, (2) fusion to pelvis, and (3) minimum 2-year follow-up. The CAP scoring methodology was created by assigning numerical values to the difference between each patient's postoperative sagittal alignment and ideal alignment as defined by previously reported age generational norms for PI-LL, PT, and TPA. CAP score ranges from −3 (if a patient is under corrected for all 3 parameters by at least 10 years) to +9 (if a patient is overcorrected by at least 30 years in all 3 parameters). A cumulative CAP score −1 to +2 represents unity between patient postop alignment and age alignment targets, CAP≤-2 represents under-correction, and CAP>+2 represents overcorrection. Postoperatively, PJK severity was categorized as None, PJK (angle 10°), Severe-PJK (28°), and PJF (PJK treated surgically). Postop HRQOL and PJK severity between each GAP and CAP categories were evaluated. RESULTS Four hundred and nine667 patients meeting inclusion criteria were evaluated. Preoperatively most of the patients had moderate to severe deformity per SRS-Schwab modifiers (PT: 26°, PI-LL=20°, and SVA=80 mm). At 2 years, mean CAP score increased from −0.8±2.4 to +0.8±2.9 (p CONCLUSIONS Evaluation of a novel ASD alignment assessment tool (CAP) demonstrates improved ability to predict the occurrence and severity of PJK compared to previously reported tools. Additionally the CAP tool correlates well with postoperative patient outcomes including HRQOL. The CAP tool may aid ASD surgical planning via use of age-adjusted alignment parameters allowing surgeons to target a postoperative alignment that minimizes complications and optimize surgical outcomes. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Relationship between body mass index and sagittal vertical axis change as well as health-related quality of life in 564 patients after deformity surgery.

Obesity, a condition that is increasing in prevalence in the United States, has previously been associated with poorer outcomes following deformity surgery, including higher rates of perioperative complications such as deep and superficial infections. To date, however, no study has examined the relationship between preoperative BMI and outcomes of deformity surgery as measured by spine parameters such as the sagittal vertical axis (SVA), as well as health-related quality of life (HRQoL) measures such as the Oswestry Disability Index (ODI) and Scoliosis Research Society-22 patient questionnaire (SRS-22). To this end, the authors sought to clarify the relationship between BMI and postoperative change in SVA as well as HRQoL outcomes. The authors performed a retrospective review of a prospectively managed multicenter adult spinal deformity database collected and maintained by the International Spine Study Group (ISSG) between 2009 and 2014. The primary independent variable considered was preoperative BMI. The primary outcome was the change in SVA at 1 year after deformity surgery. Postoperative ODI and SRS-22 outcome measures were evaluated as secondary outcomes. Generalized linear models were used to model the primary and secondary outcomes at 1 year as a function of BMI at baseline, while adjusting for potential measured confounders. Increasing BMI (compared to BMI < 18) was not associated with change of SVA at 1 year postsurgery. However, BMIs in the obese range of 30 to 34.9 kg/m2, compared to BMI < 18 at baseline, were associated with poorer outcomes as measured by the SRS-22 score (estimated change -0.47, 95% CI -0.93 to -0.01, p = 0.04). While BMIs > 30 appeared to be associated with poorer outcomes as determined by the ODI, this correlation did not reach statistical significance. Baseline BMI did not affect the achievable SVA at 1 year postsurgery. Further studies should evaluate whether even in the absence of a change in SVA, baseline BMIs in the obese range are associated with worsened HRQoL outcomes after spinal surgery.

Minimally Invasive Surgery for Mild-to-Moderate Adult Spinal Deformities: Impact on Intensive Care Unit and Hospital Stay

To compare circumferential minimally invasive (cMIS) versus open surgeries for mild-to-moderate adult spinal deformity (ASD) with regard to intensive care unit (ICU) and hospital lengths of stay (LOS). A retrospective review of 2 multicenter ASD databases with 426 ASD (sagittal vertical axis <6 cm) surgery patients with 4 or more fusion levels and 2-year follow-up was conducted. ICU stay, LOS, and estimated blood loss (EBL) were compared between open and cMIS surgeries. Propensity matching resulted in 88 patients (44 cMIS, 44 open). cMIS were older (61 vs. 53 years, P=0.005). Mean levels fused were 6.5 in cMIS and 7.1 in open (P= 0.368). Preoperative lordosis was higher in open than in cMIS (42.7° vs. 40.9°, P= 0.016), and preoperative visual analog score back pain was greater in open than in cMIS (7 vs. 6.2, P= 0.033). Preoperative and postoperative spinopelvic parameters and coronal Cobb angles were not different. EBL was 534 cc in cMIS and 1211 cc in open (P<0.001). Transfusions were less in cMIS (27.3% vs. 70.5%, P < 0.001). ICU stay was 0.6 days for cMIS and 1.2 days for open (P= 0.009). Hospital LOS was 7.9 days for cMIS versus 9.6 for open (P= 0.804). For patients with mild-to-moderate ASD, cMIS surgery had a significantly lower EBL and shorter ICU stay. Major and minor complication rates were lower in cMIS patients than open patients. Overall LOS was shorter in cMIS patients, but did not reach statistical significance.

Development of a validated computer-based preoperative predictive model for pseudarthrosis with 91% accuracy in 336 adult spinal deformity patients.

OBJECTIVEPseudarthrosis can occur following adult spinal deformity (ASD) surgery and can lead to instrumentation failure, recurrent pain, and ultimately revision surgery. In addition, it is one of the most expensive complications of ASD surgery. Risk factors contributing to pseudarthrosis in ASD have been described; however, a preoperative model predicting the development of pseudarthrosis does not exist. The goal of this study was to create a preoperative predictive model for pseudarthrosis based on demographic, radiographic, and surgical factors.METHODSA retrospective review of a prospectively maintained, multicenter ASD database was conducted. Study inclusion criteria consisted of adult patients (age ≥ 18 years) with spinal deformity and surgery for the ASD. From among 82 variables assessed, 21 were used for model building after applying collinearity testing, redundancy, and univariable predictor importance ≥ 0.90. Variables included demographic data along with comorbidities, modifiable surgical variables, baseline coronal and sagittal radiographic parameters, and baseline scores for health-related quality of life measures. Patients groups were determined according to their Lenke radiographic fusion type at the 2-year follow-up: bilateral or unilateral fusion (union) or pseudarthrosis (nonunion). A decision tree was constructed, and internal validation was accomplished via bootstrapped training and testing data sets. Accuracy and the area under the receiver operating characteristic curve (AUC) were calculated to evaluate the model.RESULTSA total of 336 patients were included in the study (nonunion: 105, union: 231). The model was 91.3% accurate with an AUC of 0.94. From 82 initial variables, the top 21 covered a wide range of areas including preoperative alignment, comorbidities, patient demographics, and surgical use of graft material.CONCLUSIONSA model for predicting the development of pseudarthrosis at the 2-year follow-up was successfully created. This model is the first of its kind for complex predictive analytics in the development of pseudarthrosis for patients with ASD undergoing surgical correction and can aid in clinical decision-making for potential preventative strategies.

Minimum clinically important difference of the health-related quality of life scales in adult spinal deformity calculated by latent class analysis: is it appropriate to use the same values for surgical and nonsurgical patients?

BACKGROUND CONTEXTHealth-related quality of life (HRQOL) parameters have been shown to be reliable and valid in patients with adult spinal deformity (ASD). Minimum clinically important difference (MCID) has become increasingly important to clinicians in evaluating patients with a threshold of improvement that is clinically relevant. PURPOSETo calculate MCID and minimum detectable change (MDC) values of total scores of the Core Outcome Measures Index (COMI), Oswestry Disability Index (ODI), Physical Component Summary (PCS), Mental Component Summary (MCS) of the Short Form 36 (SF-36), and Scoliosis Research Society 22R (SRS-22R) in surgically and nonsurgically treated ASD patients who have completed an anchor question at pretreatment and 1-year follow-up. STUDY DESIGN/SETTINGProspective cohort. PATIENT SAMPLESurgical and nonsurgical patients from a multicenter ASD database. OUTCOME MEASURESSelf-reported HRQOL measures (COMI, ODI, SF-36, SRS-22R, and anchor question). METHODSA total of 185 surgical and 86 nonsurgical patients from a multicenter ASD database who completed pretreatment and 1-year follow-up HRQOL scales and the anchor question at the first year follow-up were included. The anchor question was used to determine MCID for each HRQOL measure. MCIDs were calculated by an anchor-based method using latent class analysis (LCA) and MDCs by a distribution-based method. RESULTSAll differences between means of baseline and first year postoperative total score measures for all scales demonstrated statistically significant improvements in the overall population as well as the surgically treated patients but not in the nonsurgical group. The calculated MDC and MCID values of HRQOL parameters in the entire study population were 1.34 and 2.62 for COMI, 10.65 and 14.31 for ODI, 6.09 and 7.33 for SF-36 PCS, 6.14 and 4.37 for SF-36 MCS, and 0.42 and 0.71 for SRS-22R. The calculated MCID values for surgical and non-surgical treatment groups were 2.76 versus 1.20 for COMI, 14.96 versus 2.45 for ODI, 7.83 versus 2.15 for SF-36 PCS, 5.14 versus 2.03 for SF-36 MCS, and 0.94 versus 0.11 for SRS-22R; the MDC values for surgical and nonsurgical treatment groups were 1.22 versus 1.51 for COMI, 10.27 versus 9.45 for ODI, 5.16 versus 6.77 for SF-36 PCS, 6.05 versus 5.67 for SF-36 MCS, and 0.38 versus 0.43 for SRS-22R. CONCLUSIONSThis study has demonstrated that MCID calculations for the HRQOL scales in ASD using LCA yield values comparable to other studies that had used different methodologies. The most important finding was the significantly different MCIDs for COMI, ODI, SF-36 PCS and SRS-22 in the surgically and nonsurgically treated cohorts. This finding suggests that a universal MCID value, inherent to a specific HRQOL for an entire cohort of ASD may not exist. Use of different MCIDs for surgical and nonsurgical patients may be warranted.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P81. Successful creation of deployable preoperative predictive risk calculators for individual patient event-free survivorship for major complications, hospital readmissions and unplanned surgery following adult spinal deformity (ASD) surgery

BACKGROUND CONTEXT Few predictive models allow for proper patient selection, adjustment of invasiveness and patient frailty optimization to predict and reduce postoperative major complications (MC), hospital readmissions (READMIT), and unplanned surgery (UNPLAN). PURPOSE The objective of this project is to create accurate predictive models for the occurrence and timing of MC, READMIT, and UNPLAN following ASD surgery. STUDY DESIGN/SETTING Retrospective analysis of two independent prospective, multicenter ASD databases with identical fixed data fields. PATIENT SAMPLE Data from 1,018 ASD surgically treated patients (57 surgeons, 24 sites, and 5 countries) were used to build MC, READM and UNPLAN risk calculating models with proved successful model fit. OUTCOME MEASURES Postoperative major complications (MC), hospital readmissions (READMIT), unplanned surgery (UNPLAN). METHODS Surgical ASD patients with >2yFU were identified. Patient demographic, radiographic, operative, baseline PROMs, and complications data were analyzed to build event free survival curves for MC, READMIT and UNPLAN, and to create predictive models by means of a random survival forest with 80/20 train or test sets. 101 variables were used. Missing value imputation was performed with the missForest package. RESULTS A total of 1,018 ASD patients treated surgically before September-2014 (77.7% women, 55.5 mean age, 10.7 levels fused segments, 55.5% pelvic fixation, 21.2% 3CO) by 57 surgeons at 24 sites in 5 countries (2 continents), with 2,047.9 observation-years, were included in the analysis. Missing value imputation was 14.59%. C-statistic value (70.6%) proved successful model fit. Models demonstrate that 87.9% of patients are MC-free at 10days postop, 78.5% at 90days and 63% at 2years. Surgical invasiveness (LIV-pelvic fixation, length of fusion, prior surgery), age, magnitude of sagittal deformity, patient frailty (walking and lifting capacity) and blood loss most strongly predict MC. Surgeon and site most strongly predict READMIT and UNPLAN. Curves show a continued survivorship decrease for event free MC, READMIT and UNPLAN beyond >2yFU. CONCLUSIONS Risk calculating models for event-free MC, READMIT and UNPLAN following ASD surgery demonstrate that patient-related factors, >1/3 of which are modifiable, account for 55% of the MC predictive model weight. Surgeon and site represent 4% for MC, but are most relevant for READMIT and UNPLAN.

Friday, September 28, 2018 4:05 PM–5:05 PM abstracts: tumor and deformity: 247. Is frailty responsive to surgical correction of adult spinal deformity? An investigation of sagittal realignment and frailty component drivers

BACKGROUND CONTEXT Frailty, a relative new medical diagnosis defined by a reduced physiological reserve, has been associated with vulnerability to adverse postoperative outcomes. Recently, a novel frailty index for preoperative risk stratification in patients with adult spinal deformity (ASD-FI) was developed. Components of the ASD-FI utilize patient comorbidity history, clinical symptoms, and patient-reported-outcome-measures (PROMS). PURPOSE The goal of our study was to investigate components of the ASD-FI that are most responsive to operative intervention, and drive overall frailty score at 1Y. STUDY DESIGN/SETTING Retrospective review of a prospective multicenter adult spinal deformity database. PATIENT SAMPLE A total of 696 ASD patients. OUTCOME MEASURES PROMS: Short Form 36 (SF36) Total and Component Scores, Oswestry Disability Index (ODI). METHODS ASD patients (defined as: coronal scoliosis ≥20°, SVA ≥5cm, pelvic tilt ≥25° and/or thoracic kyphosis >60°) ≥18 years old, undergoing multilevel fusions, with complete baseline (BL) and 1Y ASD-FI scores were included. The ASD-FI is scored on a scale between 0 and 1 (no frailty: 0.5). Descriptive analysis assessed cohort demographics, radiographic parameters, and surgical details. Pearson bivariate correlations, independent and paired t-tests assessed postoperative changes to ASD-FI score components, ASD-FI total scores, and radiographic parameters. Forward hierarchal linear regression models determined the effect of successful surgical intervention (achieving lowest level SRS-Schwab classification modifiers) on change in frailty total and component scores. RESULTS A total of 696 patients were included (Mean age: 59.6, 77.4% F, 91.2% White, Mean BMI: 27.8, Mean CCI: 1.76). BL radiographic parameters: SS: 30.6, PI-LL: 16.0, PT: 24.1, SVA: 67.3, TPA: 23.7. Surgical approaches included 0.7% anterior, 69.7% posterior, 29.6% combined; 50.7% of patients had prior spine surgery, 16.4% of patients underwent staged procedures, 63.2% had an osteotomy, mean op time was 373.6 minutes, mean EBL was 1591.14ccs, mean levels fused was 5.2 anteriorly, 11.1 posteriorly, mean LOS was 7.7 days. Following surgical correction, ASD-FI score improved at 1Y (BL:0.34 vs. Y1:0.25, p CONCLUSIONS Improvements to a patient's social life, employment status, carrying groceries, climbing a flight of stairs, overall balance, and lack of leg weakness all highly correlated with improved postoperative frailty status. Although sagittal realignment correlated with frailty improvement, additional research and deformity sub-group analyses are needed to describe the association between frailty and sagittal realignment in adult spinal deformity.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P79. Patient frailty is an important contributor to disability in adult spinal deformity (ASD): rationale for routine frailty and deformity assessment

BACKGROUND CONTEXT Frailty, defined as the accumulation of physiological deficits, is used in multiple medical specialties to predict complication risk and prolonged hospital stay. Less data exist regarding the contribution of patient frailty toward compromise in patient health related quality of life. ASD frailty assessment may allow for improved patient profiling to predict disability in conjunction with spinal alignment. PURPOSE Evaluate correlations of spinal alignment and patient frailty with pre-treatment pain, disability, and patient reported outcome measures (PROMS). STUDY DESIGN/SETTING Retrospective analysis of a multicenter prospective ASD database. PATIENT SAMPLE ASD patients. OUTCOME MEASURES Oswestry Disability Index (ODI), Scoliosis Research Society-22r questionnaire (SRS-22r), SF-36, numeric rating scale (NRS) back and leg pain METHODS ASD frailty score (range 0.3–6.4) was calculated for ASD patients enrolled into a prospective database using a validated frailty scoring methodology that incorporates patient health deficits from review of systems, past medical history, general health and vitality (as recommended by Rockwood et al). PROM questions that assessed pain and/or physical function were not used in the frailty assessment, nor was patient age, to avoid confounding associations between ASD frailty score and PROMs. Correlations between age, ASA grade, total frailty score, and raw and age adjusted spinal alignment versus preop and postop ODI and SRS-22r were evaluated. ASD cohort was divided into quartiles based on worsening frailty score and propensity score matched (PSM) analysis performed controlling for age adjusted sagittal deformity (SVA, PI-LL) and max scoliosis to evaluate differences in ODI and SRS-22r between lowest (best) and highest (worst) frailty quartiles. RESULTS Mean ASD frailty score for all ASD patients (n=408) was 2.7 (SD=1.2). Correlations between preop demographic, frailty, and alignment parameters vs. preop ODI demonstrated significant associations between age, ASA grade, frailty score, SVA, and PI-LL (p CONCLUSIONS Patient frailty is an important contributor to disability and diminished physical function in ASD. Patient frailty and spinal malalignment both compromise ASD health related quality of life. Efforts should be made to routinely evaluate patient frailty and spinal malalignment when assessing disability magnitude in ASD.

Home Versus Rehabilitation: Factors that Influence Disposition After Minimally Invasive Surgery in Adult Spinal Deformity Surgery

Minimally invasive surgery (MIS) correction for adult spinal deformity (ASD) may reduce the need the need for postoperative skilled nursing facility (SNF) or inpatient rehabilitation (IR) placement following surgery. The likelihood of requiring placement in a facility rather than home disposition may be influenced by various factors. In addition, the associations between discharge location and outcomes and complication rates have not been elucidated in these patients. In this study, we aimed to define factors predicting disposition to an SNF/IR and to elucidate the rates of complications occurring in patients sent to home versus to a facility. A retrospective review of a multicenter ASD database, which included patients who underwent surgery between 2009 and 2014. Inclusion criteria were age >18 years, MIS as part of index surgery, location of discharge, and at least 1 of the following: pelvic tilt >20°, sagittal vertical axis >5 cm, pelvic incidence-lumbar lordosis mismatch >10, or lumbar scoliosis >20°. Patients with a 2-year follow-up were included. Preoperative demographic and radiographic data, postoperative (<30 day) complications, and health-related quality of life were analyzed. A total of 182 patients met our inclusion criteria, including 113 who were discharged to home and 69 who were discharged to an SNF/IR. Older patients (>50 years) were more likely to be discharged to an SNF/IR (P= 0.043). Those aged >70 years were 6-fold more likely to go to an SNF/IR. No association was identified between discharge to an SNF/IR and any radiographic parameters except preoperative pelvic tilt (odds ratio [OR], 1.11; P= 0.009). Staged cases were more likely to be discharged to an SNF/IR (OR, 3.24; 95% confidence interval, 1.11-9.46; P= 0.032); otherwise, there was no difference in levels treated, operating time, estimated blood loss, osteotomy, or length of hospital stay. Patients requiring discharge to an SNF/IR had a higher rate of complications (58% vs. 39.8%; P= 0.017), including major complications (19.5% vs. 42%; P= 0.001), perioperative complications (14.2% vs. 31.9%; P= 0.004) and infections (3.5% vs. 13%; P= 0.016). Patients discharged to an SNF/IR had a higher rate of revision (19.5% vs. 33%; P= 0.035). Health-related quality of life measures were similar regardless of disposition. Older patients and those undergoing staged MIS deformity correction have a higher likelihood of postoperative disposition to an SNF/IR. Complications occurred more commonly in those patients requiring transfer to an SNF/IR after hospitalization.

Decision-making factors in the treatment of adult spinal deformity.

We aimed to elucidate the factors for the decision-making process in the treatment of adult spinal deformity (ASD), including sagittal parameters, that impact health-related quality of life (HRQOL). A multicenter prospective ASD database was retrospectively reviewed. The demographic data, HRQOL, and radiographic measures were analyzed using multivariate analyses in younger (≤ 50years) and older (> 50years) age groups. This study included 414 patients (134 surgical and 280 nonsurgical; mean age 30.7years) in the younger age group and 575 patients (323 surgical and 252 nonsurgical; mean age 65.8years) in the older age group. Worse HRQOL measures drove surgical treatment, both in younger and older patients. The SRS-22 self-image score was the most differentiating domain, both in the younger and older age groups, and an additional significant factor in the older age group was pain and disability. Coronal deformity drove surgical treatment for the younger age group; however, older surgical patients were less likely to have coronal malalignment. Sagittal parameters were associated with the decision-making process. Greater pelvic incidence minus lumbar lordosis mismatch in the younger age group and smaller lumbar lordosis index in the older age group were most correlated with the decision to undergo surgery. Aside from the HRQOL measures and coronal deformity, sagittal parameters were identified as significant factors for the decision-making process in the ASD population, and the lack of lumbar lordosis in relation to pelvic incidence was a strong driver to pursue surgical treatment. These slides can be retrieved under Electronic Supplementary Material.

Design and Testing of 2 Novel Scores That Predict Global Sagittal Alignment Utilizing Cervical or Lumbar Plain Radiographs.

Global sagittal deformity is an established cause of disability. However, measurements of sagittal alignment are often ignored when patients present with symptoms localizing to the cervical or lumbar spine. To develop scoring scales to predict the risk of sagittal malalignment in patients with only cervical or lumbar spine radiographs. A retrospective review of a prospectively maintained multicenter adult spinal deformity database was performed. Primary outcome (sagittal malalignment) was defined as a C7 plumbline ≥ 50 mm. Two multivariate logistic regressions were performed using patient characteristics and measurements derived from cervical or lumbar radiographs as covariates. Point scores were assigned to age, body mass index (BMI), and lumbar lordosis or T1 slope by rounding their ß coefficients to the nearest integer. Nine hundred seventy-nine patients were included, with 652 randomly assigned to the derivation cohort (used to build the score) and 327 comprising the validation set. Final cervical score for the primary outcome included BMI ≥ 25 (1 point), age ≥ 55 yr (2 points), and T1 slope ≥ 27o (2 points). Final lumbar score for the primary outcome included BMI ≥ 25 (1 point), age ≥ 55 yr (1 point), and lumbar lordosis ≥ 45o (-1 points). High scores for both the cervical and lumbar spine presented with high specificity and positive likelihood ratios of sagittal malalignment. We developed scoring scales to predict global sagittal malalignment utilizing clinical covariates and cervical or lumbar radiographs. Patients with high scores may prompt imaging with long-cassette plain films to evaluate for global sagittal imbalance.

The Adult Deformity Surgery Complexity Index (ADSCI): a valid tool to quantify the complexity of posterior adult spinal deformity surgery and predict postoperative complications

Background ContextIn 2008, Mirza et al. designed and validated the first and only index capable of quantifying the complexity of spine surgery. However, this index is not fully applicable to adult spinal deformity (ASD) surgery as it does not include the surgical techniques most commonly used and most strongly associated with perioperative complications in patients with ASD. PurposeThe objective of this study is to develop an “Adult Deformity Surgery Complexity Index” (ADSCI) to quantify objectively the complexity of the ASD posterior surgery. Study Design/SettingThis is an expert consensus (Delphi process) and retrospective analysis of prospectively collected data using multiple regression models. Patient SamplePatients were prospectively enrolled in two comparable multicenter ASD databases sharing the same inclusion criteria. Outcome MeasuresThe ADSCI was internally and externally validated using R2 for intraoperative bleeding and length of surgery. Receiver operating characteristics (ROC) and area under the curve (AUC) analysis was used to assess the sensitivity and specificity of ADSCI. MethodsThe development and validation of ADSCI was based on the construction and comparison of three different tools: ADSCI score was constructed by three rounds of expert consensus (ADSCI-Delphi) and two multiple regression models (ADSCI-RM-Simple and ADSCI-RM-Mixed). Their predictive capability was compared by means of R2 values in the same subrogated of surgical complexity as in the Mirza index validation: intraoperative bleeding and duration of surgery. Sensitivity and specificity were evaluated using ROC curves and AUC analysis. The external validity was also examined by evaluating its predictive capability in another multicenter ASD database of comparable patients in the United States. ResultsAt the time of the study, the database included 1,325 patients. Four hundred seventy-five patients were eligible for the study, having been treated surgically using a posterior approach only (52.2 years standard deviation 20; 77.7% women; 85.4% American Society of Anesthesiologists I/II). Fifty-one international experts participated in the Delphi consensus process. The surgical variables selected by consensus and included in the equation were divided into actions and factors. Actions selected were number of fused segments, decompressions, interbody fusions, and cemented levels; number and type of posterior osteotomies; and use of pelvic fixation. The factors included were implant density, revision surgery, and team experience. ADSCI-RM-Mixed (regression model with Delphi formula interactions) provided the best estimates and predictive value, well above Mirza's invasiveness index. The ADSCI-RM-Mixed, with greater AUCs (>0.70), was also the most sensitive and specific for both of the dependent variables studied and for complication prediction. ADSCI-RM-Mixed obtained also the highest R2 value in the validation cohort in predicting blood loss (R2=0.34) and surgical time (R2=0.26) with effect sizes similar to those for the derivation cohort. ConclusionsThe ADSCI is the first tool to be specifically developed for the preoperative assessment of the complexity of ASD surgery. This study confirms its validity, specificity, and sensitivity, and shows that it has greater predictive capability than the more generic Mirza invasiveness index. The ADSCI should be useful for quantitatively estimating the increased risk associated with more invasive surgery and adjusting for surgical case-mix when making safety comparisons in ASDS.

A Novel Tool for Deformity Surgery Planning: Determining the Magnitude of Lordotic Correction Required to Achieve a Desired Sagittal Vertical Axis.

We sought to create a model capable of predicting the magnitude of pelvic incidence-lumbar lordosis (PI-LL) correction necessary to achieve a desired change in sagittal vertical axis (SVA). A retrospective review was conducted of a prospectively maintained multicenter adult spinal deformity database collected by the International Spine Study Group between 2009 and 2014. The independent variable of interest was the degree of correction achieved in the PI-LL mismatch 6 weeks after surgery. Primary outcome was the change in global sagittal alignment 6 weeks and 1 year after surgery. We used a linear mixed-effects model to determine the extent to which corrections in the PI-LL relationship affected postoperative changes in SVA. A total of 1053 adult patients were identified. Of these patients, 590 were managed surgically. Eighty-seven surgically managed patients were excluded because of incomplete or missing PI-LL measurements on follow-up; the remaining 503 patients were selected for inclusion. For each degree of improvement in the PI-LL mismatch at 6 weeks, the SVA decreased by 2.18 mm (95% confidence interval,-2.56,-1.79; P < 0.01) and 1.67 mm (95% confidence interval,-2.07,-1.27; P < 0.01) at 6 weeks and 12 months, respectively. A high SVA measurement (>50 mm) 1 year after surgery was negatively associated with health-related quality of life as measured by the Scoliosis Research Society 22 outcomes assessment. We describe a novel model that shows how surgical correction of the PI-LL relationship affects postoperative changes in SVA. This model may enable surgeons to determine preoperatively the amount of LL necessary to achieve a desired change in SVA.

Development of a preoperative predictive model for major complications following adult spinal deformity surgery.

OBJECTIVE The operative management of patients with adult spinal deformity (ASD) has a high complication rate and it remains unknown whether baseline patient characteristics and surgical variables can predict early complications (intraoperative and perioperative [within 6 weeks]). The development of an accurate preoperative predictive model can aid in patient counseling, shared decision making, and improved surgical planning. The purpose of this study was to develop a model based on baseline demographic, radiographic, and surgical factors that can predict if patients will sustain an intraoperative or perioperative major complication. METHODS This study was a retrospective analysis of a prospective, multicenter ASD database. The inclusion criteria were age ≥ 18 years and the presence of ASD. In total, 45 variables were used in the initial training of the model including demographic data, comorbidities, modifiable surgical variables, baseline health-related quality of life, and coronal and sagittal radiographic parameters. Patients were grouped as either having at least 1 major intraoperative or perioperative complication (COMP group) or not (NOCOMP group). An ensemble of decision trees was constructed utilizing the C5.0 algorithm with 5 different bootstrapped models. Internal validation was accomplished via a 70/30 data split for training and testing each model, respectively. Overall accuracy, the area under the receiver operating characteristic (AUROC) curve, and predictor importance were calculated. RESULTS Five hundred fifty-seven patients were included: 409 (73.4%) in the NOCOMP group, and 148 (26.6%) in the COMP group. The overall model accuracy was 87.6% correct with an AUROC curve of 0.89 indicating a very good model fit. Twenty variables were determined to be the top predictors (importance ≥ 0.90 as determined by the model) and included (in decreasing importance): age, leg pain, Oswestry Disability Index, number of decompression levels, number of interbody fusion levels, Physical Component Summary of the SF-36, Scoliosis Research Society (SRS)-Schwab coronal curve type, Charlson Comorbidity Index, SRS activity, T-1 pelvic angle, American Society of Anesthesiologists grade, presence of osteoporosis, pelvic tilt, sagittal vertical axis, primary versus revision surgery, SRS pain, SRS total, use of bone morphogenetic protein, use of iliac crest graft, and pelvic incidence-lumbar lordosis mismatch. CONCLUSIONS A successful model (87% accuracy, 0.89 AUROC curve) was built predicting major intraoperative or perioperative complications following ASD surgery. This model can provide the foundation toward improved education and point-of-care decision making for patients undergoing ASD surgery.

Complication rates associated with 3-column osteotomy in 82 adult spinal deformity patients: retrospective review of a prospectively collected multicenter consecutive series with 2-year follow-up.

OBJECTIVE Although 3-column osteotomy (3CO) can provide powerful alignment correction in adult spinal deformity (ASD), these procedures are complex and associated with high complication rates. The authors' objective was to assess complications associated with ASD surgery that included 3CO based on a prospectively collected multicenter database. METHODS This study is a retrospective review of a prospectively collected multicenter consecutive case registry. ASD patients treated with 3CO and eligible for 2-year follow-up were identified from a prospectively collected multicenter ASD database. Early (≤ 6 weeks after surgery) and delayed (> 6 weeks after surgery) complications were collected using standardized forms and on-site coordinators. RESULTS Of 106 ASD patients treated with 3CO, 82 (77%; 68 treated with pedicle subtraction osteotomy [PSO] and 14 treated with vertebral column resection [VCR]) had 2-year follow-up (76% women, mean age 60.7 years, previous spine fusion in 80%). The mean number of posterior fusion levels was 12.9, and 17% also had an anterior fusion. A total of 76 early (44 minor, 32 major) and 66 delayed (13 minor, 53 major) complications were reported, with 41 patients (50.0%) and 45 patients (54.9%) affected, respectively. Overall, 64 patients (78.0%) had at least 1 complication, and 50 (61.0%) had at least 1 major complication. The most common complications were rod breakage (31.7%), dural tear (20.7%), radiculopathy (9.8%), motor deficit (9.8%), proximal junctional kyphosis (PJK, 9.8%), pleural effusion (8.5%), and deep wound infection (7.3%). Compared with patients who did not experience early or delayed complications, those who had these complications did not differ significantly with regard to age, sex, body mass index, Charlson Comorbidity Index, American Society of Anesthesiologists score, smoking status, history of previous spine surgery or spine fusion, or whether the 3CO performed was a PSO or VCR (p ≥ 0.06). Twenty-seven (33%) patients had 1-11 reoperations (total of 44 reoperations). The most common indications for reoperation were rod breakage (n = 14), deep wound infection (n = 15), and PJK (n = 6). The 24 patients who did not achieve 2-year follow-up had a mean of 0.85 years of follow-up, and the types of early and delayed complications encountered in these 24 patients were comparable to those encountered in the patients that achieved 2-year follow-up. CONCLUSIONS Among 82 ASD patients treated with 3CO, 64 (78.0%) had at least 1 early or delayed complication (57 minor, 85 major). The most common complications were instrumentation failure, dural tear, new neurological deficit, PJK, pleural effusion, and deep wound infection. None of the assessed demographic or surgical parameters were significantly associated with the occurrence of complications. These data may prove useful for surgical planning, patient counseling, and efforts to improve the safety and cost-effectiveness of these procedures.

Sagittal malalignment has a significant association with postoperative leg pain in adult spinal deformity patients.

To evaluate the association between spinopelvic sagittal parameters and leg pain in patients with adult spinal deformity (ASD) after adjusting for demographic and surgical variables. A multicenter prospective ASD database (European Spine Study Group) was retrospectively reviewed. The characteristics (age, sex, body mass index, comorbidity, history of spine surgery, and radiographical coronal and sagittal parameters) of patients with preoperative and 6-month postoperative leg pain (PostLP; numerical rating scale score≥5) were analyzed using univariate and multivariate analyses. In this study, 204 patients (164 women and 40 men; mean age 53.1years) were included. Fifty-three percent of the patients had preoperative leg pain (PreLP). The patients with PreLP had significantly worse sagittal parameters and less coronal Cobb angle than those with less leg pain; however, this association disappeared after adjustment for covariates. The PreLP of the ASD patients was successfully treated surgically in most cases; however, 24% of the patients still had unexpected residual leg pain. Postoperative sagittal malalignment (sagittal vertical axis≥40mm, T1 sagittal tilt≥0°, pelvic tilt≥30°) was a significant risk factor of PostLP even after adjusting for covariates. Leg pain in patients with ASD was significantly associated with sagittal malalignment especially after surgical treatments. As these patients lose flexibility in the fused spinal segment, they can only depend on the remaining compensatory mechanisms below the pelvis (e.g., the hips and knees) to maintain a balanced posture. This may lead to a predisposition of these patients to postoperative leg symptoms related to spinal sagittal malalignment.