Faculty Bibliography

BACKGROUND CONTEXT: Adult spinal deformity (ASD) surgery is costly and carries a high complication rate. It is therefore very important to optimize value (cost-per-QALY) or cost-utility in ASD surgery. To identify targets for improvement, we compared the influence of patient factors, measured by frailty, vs surgical factors, measured by surgical invasiveness (SI), on 2-year cost-utility. Patient frailty is an approximation of baseline patient health status, whereas SI represents extensiveness of the surgical intervention. Data comparing the relative importance of these aggregate measures on cost-utility are limited. Additionally, this analysis can serve to help identify the most impactful modifiable factors in the value equation. PURPOSE: The aim of this study was to assess whether frailty or SI is a more important determinant of 2-year cost-utility in ASD surgery. STUDY DESIGN/SETTING: Prospective, multicenter study. PATIENT SAMPLE: ASD patients with >4-level fusion and eligible for minimum 2-year follow-up were included. OUTCOME MEASURES: Two-year cost-per-QALY.
METHOD(S): Index and total episode of care (EOC; iEOC; tEOC) cost was calculated using Medicare's inpatient prospective payment system (IPPS) for MS-DRGs 453-460. All costs were adjusted for inflation to 2020 US dollar values. QALYs gained were calculated using baseline, 1-year, and 2-year SF-6D scores. A discount rate of 3% was assumed. Cost-per-QALY was determined by calculating total EOC per cumulative QALY at two years. Patients were categorized as not-frail (NF, <0.3), frail (F, 0.3<= to <0.5), and severely frail (SF, >0.5). SI was categorized as low-SI (SI<90) and high-SI (SI>90). A generalized linear model with gamma error distribution and log link was used to estimate the association between frailty and SI on cost-per-QALY. All analyses were controlled for gender and blood loss. Other variables commonly adjusted for (ie, age, levels fused) were intentionally not controlled for in this analysis to avoid collinearity with either frailty or SI.
RESULT(S): DRG data for index and revision surgery was available for 505/889 patients. Mean age was 62.5+12.4years, 76% were women, and 91% were Caucasian. Of the total patients,72% demonstrated positive gain in QALY at 2 years (0.12+0.09, p<0.001) compared to baseline. The mean iEOC was $72,717, tEOC was $86,066, and cost-per-QALY was $52,357. Eighty-nine patients had 114 (range 1-5) revisions (17.6%) compared to 416 without. The tEOC in revision group was $151,913 compared to $71,978 in the non-revision group with 2-year cost-per-QALY 98,262 compared to 42,537, respectively. On adjusted analysis, F and SF patients compared to NF patients had significantly higher cost-per-QALY (p<0.0001 for all comparisons) regardless of the surgical invasiveness. However, SI was not significantly associated with cost-per-QALY regardless of patient's frailty.
CONCLUSION(S): Increasing levels of frailty were associated with significantly and incrementally higher values of 2-year cost-per-QALY in both low and high SI groups. However, within each frailty group, the high and low SI groups had equivalent cost-per-QALY. Frailty appears to be a better determinant of 2-year cost-per-QALY compared to surgical invasiveness. Surgeons should place more importance on modifiable patient factors compared to surgical factors to improve or optimize 2-year cost-utility in ASD surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Cervical alignment and cervical deformity surgery are complex topics. Recently, a score inspired by work on thoracolumbar alignment was developed for cervical alignment (cervical deformity score, CDS). While this score was designed to predict early mechanical failures, its association with patient reported outcomes (PROM) remains unclear. PURPOSE: Investigate the association between PROM, complications, and a newly described cervical deformity score. STUDY DESIGN/SETTING: Retrospective review of prospective multicenter database. PATIENT SAMPLE: A total of 102 adult cervical deformity (CD) patients with at least 1 year follow-up. OUTCOME MEASURES: NDI, neck pain, EQ5D, complication rates.
Method(s): CD patients with baseline and 1-year follow-up were included. Postoperative CDS was constructed using offset from age-adjusted values: SVA [(age -55)*2+25], T1 Slope [(age -55)/4 + 28.7], and TS minus CL [cst: between 26.5 and 14.5degree]. Points were assigned based on the offset from alignment targets and the CDS was the sum of the three individual scores. Association with patient-reported outcomes was investigated using Pearson's correlations. Comparison of CDS between patients with and without complication within 1-year was conducted. Logistical regression controlling for demographic and comorbidities was conducted to identify if CDS was an independent predictor of complications.
Result(s): A total of 102 patients met inclusion criteria (61.7yo+/-10, 66.7% F); 37.6% of them had a history of previous cervical surgery (16.7% previous ACDF, 11.7% previous posterior fusion). Preoperatively, they had elevated disability (NDI: 47.1+/-18.1), pain (NSR Neck: 6.6+/-2.5), myelopathy (mJOA: 13.6+/-2.7) and lower general health (EQ5D: 0.74+/-0.07). They also presented with an overall cervical kyphotic alignment (C2-C7: -6.3degree+/-20.9), a moderate cervical anterior alignment (cSVA: 39mm+/-20; TS-CL: 37.9degree+/-19.4) and a posterior global thoracolumbar alignment (SVA: -3mm+/-68). The median of number of levels fused was 7 [4-9], with 49% treated with a posterior approach and 30.4% with a combined approach; 83.2% received an osteotomy, 44.6% some posterior osteotomy, 16.8% grade 6 or 7. The mean operative time was 368min+/-208, median EBL was 525cc [200 1025], and LOS was 5 days [4 8]. At 1 year, patients improved significantly in terms of disability (NDI: 36.2+/-20.7, 60.8% reached MCID), pain (NSR: 4.1+/-2.9) and general health (EQ5D: 0.79+/-0.08) (all p<0.001). The cervical alignment significantly changed (C2-C7: 7.8+/-14.5m; cSVA: 34mm+/-15; TS-CL: 28.9degree+/-12.6 all p <0.002), with a 1-year CDS of 1.68+/-2.46 (prctl [0 3.25]). There was a significant association between increased CDS and increased disability (r=0.273), pain (r=0.336) and lower general health (r=-0.283). Patient with a lower disability level (NDI<20) had a significantly lower CDS (0.71+/-2.3 vs 2.16+/-2.4 p<0.004). Patients without any complications before 1 year had a lower CDS (0.78+/-2.33 vs 2.18+/-2.40 p=0.005), as did patients without major complications (1.36+/-2.27 vs 2.50+/-.78 p=0.037). Deeper analysis revealed significant differences in terms of CDS for patients experiencing cardiopulmonary, instrumentation and radiographic complications (p<0.05). Multivariate analysis, controlling for age and comorbidities, show 1-year CDS to be a significant predictor of complication (p=0.002, OR=1.409).
Conclusion(s): With better outcomes and lower complication rate, maintaining a proportionate alignment postoperatively can result in superior outcomes following CD surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Hounsfield unit values (HU) from computed tomography (CT) have been used to informally assess bone density in patients undergoing spine fusion procedures. HUs are easily obtained from a standard preoperative CT scan, and unlike Dual X-ray Absorptiometry analysis (DEXA) one can focus on specific regions of interest, such as the vertebral body of a planned upper-instrumented vertebrae (UIV). There is still a relative lack of literature on the reliability and utility of HUs to both identify patients with low BMD and guide surgical decision making. PURPOSE: To determine whether there was a significant difference in preoperative HUs, measured at the UIV, in patients that had a bone-density related complication (DRC) within 2 years of their spinal fusion. STUDY DESIGN/SETTING: A retrospective comparative study at a single academic institution. PATIENT SAMPLE: Patients 55 years or older that underwent a spinal fusion procedure in 2017 at a single academic institution. OUTCOME MEASURES: Occurrence of proximal junctional kyphosis, proximal junctional failure, pseudarthrosis, screw loosening or pullout, hardware failure and adjacent segment disease (ASD).
METHOD(S): Baseline preoperative demographic information, smoking history, levels fused, UIV and status as a revision procedure were recorded. All postoperative notes and images for 2 years post-procedure were reviewed for the presence of proximal junctional kyphosis, proximal junctional failure, pseudarthrosis, screw loosening or pullout, hardware failure, and ASD. HUs were measured via regions of interest drawn within the cancellous bone of the mid-vertebral body at the UIV of all patients. Patients were divided into 2 groups for comparison, those who experienced a DRC within 2 years and those who did not. Student's t-test was performed to compare HUs between the groups, chi-square analysis was performed for categorical variables. Dichotomous logistical regression was performed to analyze the relationship between density related complications and HU at the UIV, patient BMI, revision procedure, history of smoking, gender, UIV and number of levels fused. Significance was set at p<0.05.
RESULT(S): A total of 172 consecutive fusion patients with a preoperative CT scan were reviewed. Of these, 49 were revision procedures. 66 had a UIV in the cervical spine, 10 had a UIV in the thoracic spine and 95 had a UIV in the lumbar spine. Ninety-nine were 1 or 2 level fusions, 49 were 3 or 4 level fusions and 23 were long fusions with 4+ levels involved. Forty-eight patients had a DRC. Baseline demographics were similar between the 2 groups, with the exception of more revision procedures in the DRC group (p<0.001). The mean HUs of the UIV in the cohort that had a DRC was 168.92, as compared to 252.66 in the no-DRC group (p<0.001). Regression analysis revealed that low HUs at the UIV and revision procedures were independent risk factors for a DRC. For every 10 unit decrease in HUs, the odds of a DRC rose by 6%. When thoracic and lumbar fusions were analyzed the mean HUs at the UIV in the DRC group were 108.5 vs 152.6 (p<0.001). When cervical fusions were analyzed separately the mean HUs in the DRC group were 308 vs 383.4 (P=0.014).
CONCLUSION(S): To our knowledge, this is the first study that compares HUs measured at the UIV to the rate of density related complications for single and multilevel fusions in the cervical, thoracic and lumbar spine. This study found that HUs measured at the UIV of a fusion were significantly lower in patients that went on to have a density related complication within 2 years of their index procedure. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Surgeons may preferentially limit fusion levels for younger vs older ASD patients to maintain motion segments and optimize postoperative function. Few data exist comparing the functional impact of upper thoracic (UT) vs thoracolumbar (TL) upper instrumented vertebra (UIV) in younger vs older ASD patients undergoing long fusion to the pelvis. PURPOSE: Evaluate patient reported functional impact of UT vs TL UIV in younger vs older ASD patients undergoing long fusion to the pelvis. STUDY DESIGN/SETTING: Propensity score matched (PSM) analysis of ASD patients prospectively enrolled into a multicenter study. PATIENT SAMPLE: Surgically treated ASD patients prospectively enrolled into multicenter study. OUTCOME MEASURES: Numeric rating scale (NRS) back and leg pain, Scoliosis Research Society-22r questionnaire (SRS-22r), Short Form-36v2 questionnaire (SF-36), Oswestry Disability Index (ODI), estimated blood loss, duration of hospital stay, postoperative complications, revision spine surgery.
METHOD(S): Surgically treated ASD patients prospectively enrolled into a multicenter ASD study were divided into 2 age groups (younger= <65 years, older= > 65 years) and separated according to UIV (TL= L2-T7; UT= T6-T1). Study inclusion criteria; 1) surgery for Lumbar (L), Sagittal (S), or Mixed (M) deformities (as per SRS-Schwab ASD classification), 2) fusion to the pelvis, 3) minimum 5 levels fused, and 4) minimum 2 year postop follow up. Surgery for double major or thoracic scoliosis were excluded. PSM was used to match preop patient demographics, scoliosis, and sagittal spinopelvic parameters including PI-LL, TK, SVS, and TPA. Surgical data evaluated and impact of UIV upon patient reported functional outcomes compared for UT vs TL for younger vs older.
RESULT(S): From 2008-2018, 435 of 717 eligible surgically treated patients were evaluated; younger (n=193; mean age 57.6 years) and older (n=242; mean age 72.3 years), mean levels fused UT=17.4, TL=10.7 (p<0.05). Preop spine deformity, demographics, and performance of osteotomies were similar for matched UT vs TL in younger and older (p>0.05). Surgical blood loss, duration of SICU and hospital stay was greater for UT vs TL in younger and older (p<0.05). UT had more revision surgery than TL due to implant failures in younger (20% vs 3%) and older (16% vs 1%), respectively (p<0.05). Older UT had more major complications than older TL (65% vs 30%). At minimum 2 year postoperative follow up spine deformity correction and all PROMs (including improvements and final values) including SRS-22r activity, SF-36 physical function, SF-36 role physical, SF-36 social function and SF-36 vitality were similar UT vs TL in younger and older (p>0.05).
CONCLUSION(S): Younger ASD patients fused to the pelvis do not report more physical restrictions for UT vs TL UIV compared to older ASD patients, however blood loss, SICU and hospital stay and complications were greater for UT vs TL in younger and older cohorts. When deciding upon UIV for ASD patients, the minimal impact of UT vs TL UIV upon patient reported outcomes must be offset by cognizance of a longer hospital stay and potential for greater postoperative complications for UT fusions especially in older patients. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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STUDY DESIGN/METHODS:Longitudinal cohort. OBJECTIVES/OBJECTIVE:The aim of this study was to examine the relationship between patient satisfaction, patient-reported outcome measures (PROMs) and radiographic parameters in adult spine deformity (ASD) patients undergoing three-column osteotomies (3CO). SUMMARY OF BACKGROUND DATA/BACKGROUND:Identifying factors that influence patient satisfaction in ASD is important. Evidence suggests Scoliosis Research Society-22R (SRS-22R) Self-Image domain correlates with patient satisfaction in patients with ASD. METHODS:This is a retrospective review of ASD patients enrolled in a prospective, multicenter database undergoing a 3CO with complete SRS-22R pre-op and minimum 2-years postop. Spearman correlations were used to evaluate associations between the 2-year SRS Satisfaction score and changes in SRS-22R domain scores, Oswestry Disability Index (ODI), and radiographic parameters. RESULTS:Of 135 patients eligible for 2-year follow-up, 98 patients (73%) had complete pre- and 2-year postop data. The cohort was mostly female (69%) with mean BMI of 29.7 kg/m2 and age of 61.0 years. Mean levels fused was 12.9 with estimated blood loss of 2695 cc and OR time of 407 minutes; 27% were revision surgeries. There was a statistically significant improvement between pre- and 2-year post-op PROMs and all radiographic parameters except Coronal Vertical Axis. The majority of patients had an SRS Satisfaction score of ≥3.0 (90%) or ≥4.0 (68%), consistent with a moderate ceiling effect. Correlations of patient satisfaction was significant for Pain (0.43, P < 0.001), Activity (0.39, P < 0.001), Mental (0.38, P = 0.001) Self-Image (0.52, P < 0.001). ODI and Short-Form-36 Physical component summary had a moderate correlation as well, with mental component summary being weak. There was no statistically significant correlation between any radiographic or operative parameters and patient satisfaction. CONCLUSION/CONCLUSIONS:There was statistically significant improvement in all PROMs and radiographic parameters, except coronal vertical axis at 2 years in ASD patients undergoing 3CO. Improvement in SRS Self-Image domain has the strongest correlation with patient satisfaction.Level of Evidence: 3.

Purpose/UNASSIGNED:The aim is to investigate the relationship between cervical parameters and the modified Japanese Orthopedic Association scale (mJOA). Materials and Methods/UNASSIGNED:> 0.05), Pearson correlations were run for radiographic parameters and mJOA. For significant correlations, logistic regressions were performed to determine a threshold of radiographic measures for which the correlation with mJOA scores was most significant. mJOA score of 14 and <12 reported cut-off values for moderate (M) and severe (S) disability. New modifiers were compared to an existing classification using Spearman's rho and logistic regression analyses to predict outcomes up to 2 years. Results/UNASSIGNED:= 0.002). Compared to existing Ames- International Spine Study Group classification, the novel thresholds demonstrated significant predictive value for reoperation and mortality up to 2 years. Conclusions/UNASSIGNED:Collectively, these radiographic values can be utilized in refining existing classifications and developing collective understanding of severity and surgical targets in corrective surgery for adult CD.

STUDY DESIGN/METHODS:Retrospective review of a single-center spine database. OBJECTIVE:Investigate the intersections of chronological age and physiological age via frailty to determine the influence of surgical invasiveness on patient outcomes. SUMMARY OF BACKGROUND DATA/BACKGROUND:Frailty is a well-established factor in preoperative risk stratification and prediction of postoperative outcomes. The surgical profile of operative adult spinal deformity (ASD) patients who present as elderly and not frail has yet to be investigated. Our aim was to examine the surgical profile and outcomes of ASD patients who were not frail and elderly. METHODS:Included: ASD patients≥18 years old, ≥4 levels fused, with baseline(BL) and follow up data. Patients were categorized by ASD frailty index: Not Frail[NF], Frail[F], Severely Frail [SF]. An elderly patient was defined as ≥70 years. Patients were grouped into NF/elderly and F/elderly. SRS-Schwab modifiers were assessed at baseline and 1-year(0, +, ++). Logistic regression analysis assessed the relationship between increasing invasiveness, no reoperations, or major complications, and improvement in SRS-Schwab modifiers[Good Outcome]. Decision tree analysis assessed thresholds for an invasiveness risk/benefit cutoff point. RESULTS:598 ASD pts included(55.3yrs, 59.7%F, 28.3 kg/m2). 29.8% of patients were above age 70. At baseline, 51.3% of patients were NF, 37.5% F, and 11.2% SF. 66(11%) of patients were NF and elderly. 24.2% of NF-Elderly patients improved in SRS-Schwab by 1-year and had no reoperation or complication postoperatively. Binary regression analysis found a relationship between worsening SRS-Schwab, postop complication, and reoperation with invasiveness score(OR: 1.056[1.013-1.102], p = 0.011). Risk/benefit cut-off was 10(p = 0.004). Patients below this threshold were 7.9[2.2-28.4] times more likely to have a Good Outcome. 156 patients were elderly and F/SF with 16.7% having Good Outcome, with a risk/benefit cut-off point of <8 (4.4[2.2-9.0], p < 0.001). CONCLUSIONS:Frailty status impacted the balance of surgical invasiveness relative to operative risk in an inverse manner, while the opposite was seen amongst elderly patients with a frailty status less than their chronologic age. Surgeons should perhaps consider incorporation of frailty status over age status when determining realignment plans in patients of advanced age.Level of Evidence: ???

STUDY DESIGN/METHODS:Retrospective review. OBJECTIVES/OBJECTIVE:The aim of this study was to define a surgical invasiveness threshold that predicts major complications after adult spinal deformity (ASD) surgery; use this threshold to categorize patients into quartiles by invasiveness; and determine the odds of major complications by quartile. SUMMARY OF BACKGROUND DATA/BACKGROUND:Understanding the relationship between surgical invasiveness and major complications is important for estimating the likelihood of major complications after ASD surgery. METHODS:Using a multicenter database, we identified 574 ASD patients (more than 5 levels fused; mean age, 60 ± 15 years) with minimum 2-year follow-up. Invasiveness was calculated as the ASD Surgical and Radiographic (ASD-SR) score. Youden index was used to identify the invasiveness score cut-off associated with optimal sensitivity and specificity for predicting major complications. Resulting high- and low-invasiveness groups were divided in half to create quartiles. Odds of developing a major complication were analyzed for each quartile using logistic regression (alpha = 0.05). RESULTS:The ASD-SR cutoff score that maximally predicted major complications was 90 points. ASD-SR quartiles were 0 to 65 (Q1), 66 to 89 (Q2), 90 to 119 (Q3), and ≥120 (Q4). Risk of a major complication was 17% in Q1, 21% in Q2, 35% in Q3, and 33% in Q4 (P < 0.001). Comparisons of adjacent quartiles showed an increase in the odds of a major complication from Q2 to Q3 (odds ratio [OR] 1.8; 95% confidence interval [CI]: 1.0-3.0), but not from Q1 to Q2 or from Q3 to Q4. Patients with ASD-SR scores ≥90 were 1.9 times as likely to have a major complication than patients with scores <90 (OR 1.9, 95% CI 1.3-2.9). Mean ASD-SR scores above and below 90 points were 121 ± 25 and 63 ± 17, respectively. CONCLUSION/CONCLUSIONS:The odds of major complications after ASD surgery are significantly greater when the procedure has an ASD-SR score ≥90. ASD-SR score can be used to counsel patients regarding these increased odds.Level of Evidence: 3.

STUDY DESIGN/METHODS:Retrospective cohort analysis. OBJECTIVE:The aim of this study was to compare postoperative outcomes of Coflex interspinous device versus laminectomy. SUMMARY OF BACKGROUND DATA/BACKGROUND:Coflex Interlaminar Stabilization device (CID) is indicated for one- or two-level lumbar stenosis with grade 1 stable spondylolisthesis in adult patients, as an alternative to laminectomy, or laminectomy and fusion. CID provides stability against progressive spondylolisthesis, retains motion, and prevents further disc space collapse. METHODS:Patients ≥18 years' old with lumbar stenosis and grade 1 stable spondylolisthesis who underwent either primary single-level decompression and implantation of CID, or single-level laminectomy alone were included with a minimum 90-day follow-up at a single academic institution. Clinical characteristics, perioperative outcomes, and postoperative complications were reviewed until the latest follow-up. χ2 and independent samples t tests were used for analysis. RESULTS:Eighty-three patients (2007-2019) were included: 37 cases of single-level laminectomy (48.6% female) were compared to 46 single-level CID (50% female). CID cohort was older (CID 69.0 ± 9.4 vs. laminectomy 64.2 ± 11.0, P = 0.042) and had higher American Society of Anesthesiologists (ASA) grade (CID 2.59 ± 0.73 vs. laminectomy 2.17 ± 0.48, P = 0.020). CID patients had higher estimated blood loss (EBL) (97.50 ± 77.76 vs. 52.84 ± 50.63 mL, P = 0.004), longer operative time (141.91 ± 47.88 vs. 106.81 ± 41.30 minutes, P = 0.001), and longer length of stay (2.0 ± 1.5 vs. 1.1 ± 1.0 days, P = 0.001). Total perioperative complications (21.7% vs. 5.4%, P = 0.035) and instrumentation-related complication was higher in CID (10.9% vs. 0% laminectomy group, P = 0.039). There were no other significant differences between the groups in demographics or outcomes. CONCLUSION/CONCLUSIONS:Single-level CID devices had higher perioperative 90-day complications, longer operative time, length of stay, higher EBL compared to laminectomies alone. Similar overall revision and neurologic complication rates were noted compared to laminectomy at last follow-up.Level of Evidence: 3.

STUDY DESIGN/UNASSIGNED:Retrospective cohort study. OBJECTIVES/UNASSIGNED:The interactions between hip osteoarthritis (OA) and spinal malalignment are poorly understood. The purpose of this study was to assess the influence of total hip arthroplasty (THA) on standing spinopelvic alignment. METHODS/UNASSIGNED:In this retrospective cohort study, patients undergoing THA for OA with pre-and postoperative full-body radiographs were included. Standing spinopelvic parameters were measured. Contralateral hip was graded on the Kellgren-Lawrence scale. Pre-and postoperative alignment parameters were compared by paired t-test. The severity of preoperative thoracolumbar deformity was measured using TPA. Linear regression was performed to assess the impact of preoperative TPA and changes in spinal alignment. Patients were separated into low and high TPA (<20 or >/=20 deg) and change in parameters were compared between groups by t-test. Similarly, the influence of K-L grade, age, and PI were also tested. RESULTS/UNASSIGNED:= .004). Preoperative TPA was significantly associated with the change in PI-LL, SVA, and TPA. High TPA patients significantly decreased SVA more than low TPA patients. There was no significant impact of contralateral hip OA, PI, or age on change in alignment parameters. CONCLUSION/UNASSIGNED:Spinopelvic alignment changes after THA, evident by a reduction in SVA. Preoperative spinal sagittal deformity impacts this change. Level of evidence: III.