Faculty Bibliography

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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BACKGROUND CONTEXT: With the rise of health care costs and a focus on value-based outcomes, hospitals have become more cognizant on cost of revisions and complications. However, literature on the effect of distal junctional kyphosis in driving up health care costs is scarce. PURPOSE: To evaluate the effect of distal junctional kyphosis on the cost effectiveness of corrective cervical deformity surgery. STUDY DESIGN/SETTING: Retrospective review of a single surgeon database. PATIENT SAMPLE: This study included 123 cervical deformity patients. OUTCOME MEASURES: Cost per QALY.
METHOD(S): Cervical deformity patients with minimum 1-year HRQL follow-up were included. Means comparison tests assessed differences in baseline demographic and clinical data. Utility data was calculated using published conversion methods to convert NDI to SF-6D. QALYs utilized a 3% discount rate to account for residual decline to life expectancy (78.7 years). Costs was calculated using the PearlDiver database incorporating complications, comorbidities (CC), major complications, and comorbidities (MCC) were assessed according to CMS.gov manual definitions. Reimbursement consisted of a standardized estimate using regression analysis of Medicare pay-scales for all services rendered within a 30-day window, including estimates regarding costs of postoperative complications, outpatient health care encounters, revisions and medical-related readmissions. After accounting for CC, MCC, length of stay (LOS) and death, cost per QALY at 2Y was calculated for revisions due to distal junctional kyphosis.
RESULT(S): A total of 123 cervical deformity patients met inclusion criteria (57.22yrs, 54%F, 29.0kg/m2). At baseline, patients presented radiographically as: PT (16.9+/-9.7), PI (54.7+/-11.4), PI-LL (-2.9+/-12.6), SVA (80.5+/-49.8), cSVA (28.4+/-20.6), TS-CL (26.6+/-14.4). Surgical details: EBL of 708 mL, operative time of 438.6 min, with 29.51% undergoing an anterior approach, 50.82% posterior-only approach, and 19.67% combined approach. Overall, 7.9% of patients developed DJK within two years postoperatively. Average cost of revision surgery due to DJK within 2years of index surgery was $50,736 +/- 31,467. Patients that developed DJK within 2years of index surgery trended toward having a greater baseline NDI (62.8 vs 55.47, p>0.05) and showed less improvement in NDI at 2 years (4 vs 16.6). Overall, cost per QALY was higher for patients developing DJK at 2 years ($28,483 vs $20,989).
CONCLUSION(S): Cervical deformity revisions due to distal junctional kyphosis had a cost per QALY of $28,483. Efforts to limit postoperative DJK after surgical intervention can further limit additional costs associated with revisions and complications. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Frailty has been utilized in cervical deformity (CD) to characterize the influence of preop health state on postop outcomes. Frailty severity may be an important determinant for impaired recovery after CD corrective surgery. No prior studies have examined the associations between increasingly frail states and the trajectory of recovery in CD realignment. PURPOSE: Evaluate postop clinical recovery among CD patients between frailty states undergoing primary procedures STUDY DESIGN/SETTING: Retrospective review of a prospective CD database PATIENT SAMPLE: A total of 106 CD patients. OUTCOME MEASURES: Baseline (BL) to 1-Year(1Y) HRQL Instruments: NDI, mJOA, EQ5D METHODS: Patients>18yrs undergoing surgery for CD (C2-7 Cobb>10degree, coronal Cobb>10degree, cSVA>4cm or TS-CL>10degree, or CBVA>25degree) with HRQL data at BL, 3M and 1Y postop intervals were identified. Patients were stratified by the modified CD frailty index (mCD-FI, Passias et al.) scale from 0-1 (no frailty:<0.3[NF], mild/severe: >0.3[F]). Patients in NF and F groups were propensity score matched (PSM) for TS-CL to control for baseline deformity. Demographics, alignment and Ames-ISSG deformity modifiers were assessed using chi-squared and paired t-tests to compare HRQL outcomes. HRQL outcomes were normalized by dividing BL and postop (3M, 1Y) outcomes by BL for each patient. Normalized scores (y-axis) were plotted against duration of follow-up (x-axis). AUC was calculated for follow-up time intervals; total area for each follow-up interval was divided by cumulative follow-up, determining overall normalized, time-adjusted HRQL outcomes (Integrated Health State [IHS]). IHS was compared between NF and F groups.
RESULT(S): A total of 106 CD patients included (61.7yrs, 66% F, 27.7kg/m2). By frailty group: 52.8% NF, 47.2% F. After PSM for TS-CL (mean: 38.1degree), 38 patients remained in each of the NF and F groups. By surgical approach, 46.1% underwent posterior approach, 19.7% anterior, and 34.2% combined; which was not significant between the frailty groups(p>0.05). At baseline, cervical and spinopelvic radiographic parameters were not significant, except for the C7-S1 SVA (NF: -26.5mm vs F: 15.2mm, p=0.007). According to BL HRQLs, F patients displayed significantly worse NDI scores (NF: 36.8 F: 55.4; p<0.001), mJOA (NF: 14.7, F: 12.7; p=0.002), and EQ5D (NF: 0.78, F: 0.69; p<0.001). All frailty groups exhibited BL to 1Y improvement in NDI, EQ5D and NRS Neck Pain (all p<0.001). After HRQL normalization, F patients had more improvement in mJOA scores at 3M (p=0.065) as well as NDI (p=0.096) and EQ5D (p=0.016). IHS-adjusted HRQL outcomes from BL to 1Y showed a significant difference in EQ5D scores (NF: 1.02, F: 1.07, P=0.016). No significant differences were found in the IHS NDI and mJOA between frailty groups (p>0.05). F patients had more postop major complications (31.3%) compared to the NF (8.9%), p=0.004, though DJK occurrence and reoperation between the groups was not significant.
CONCLUSION(S): While all groups exhibited improved postop disability/pain scores, frail patients recovered better in overall health state. Despite frail patients having more complications, they seem to have overall better patient-reported outcomes, signifying that with frailty severity, patients have more room for improvement postop compared to baseline quality of life. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: While advances have been made in the surgical management of distal junctional kyphosis (DJK), complication rates remain high. Although individual factors related to its occurrence have been cited, many of these cases are mild and have no clinical relevance nor have these been combined into a formal predictive model, particularly for cases that are clinically impactful. PURPOSE: Develop a formal predictive model distinguishing between symptomatic and asymptomatic DJK. STUDY DESIGN/SETTING: Retrospective review PATIENT SAMPLE: A total of 99 cervical deformity patients (CD) with 1 year (1Y) follow up OUTCOME MEASURES: Complications; reoperations; HRQL, alignment METHODS: CD patients (pts) were stratified into asymptomatic (Asym) and symptomatic (Sym) DJK. DJK angle (DJKA) was defined >10degree change in kyphosis between LIV and LIV-2 and a >10degree index angle. Asym: DJK to be>10degree in the absence neurologic sequelae. Sym: 1) DJKA> 10degree and either reop due to DJK or >one new-onset neurological sequelae related to DJK or 2) pts who had either a DJKA > 20degree or DJKA > 20degree. Stepwise logistic regressions were used to identify patient-specific, surgical, radiographic and HRQL factors that were associated with these types of DJK. Decision tree analysis established cut-offs for the continuous variables.
RESULT(S): A total of 99 CD pts were included (60yrs, 26.5kg/m2, 66.7%F). Surgical characteristics: 7.4+/-4 levels fused, 47.5% posterior, 18.2% anterior, and 34.3% combined. Overall, 32.2% developed DJK (34.3% Asym, 65.7% Sym). 37.5% of Asym pts received a reop vs 62.5% Sym pts. At BL, Asym pts had a greater BMI (28.5 vs 23kg/m2) and NSR back pain (5.2 vs 4.6; all p<0.05). Decision tree analysis identified osteoporosis, UIV level, and the apex of the region of the spine where the primary deformity is located to predict Sym pts. Top factors predicting Sym pts over Asym were BL EQ5D>0.65, UIV cephalad to C2, and C2-C7 apex caudal to C5. Multivariate analysis identified independent radiographic and surgical factors for developing Sym DJK: [Radiographic] BL PI (1.02[0.9-1.07]), preop cervical flexibility (1.04[1.01-1.07]); [Surgical] combined approach (6.2[1.4-27]; all p<0.05). Having abnormal hyper kyphosis in the thoracic spine, more so than abnormal cervical lordosis, was an independent factor for developing Sym when analyzed against Asym pts (1.2[0.01-115]). Predictive modeling identified factors that were predictive of Sym against no DJK pts such as having myelopathy (mJOA score:12-14), combined approach, UIV=C3 or C4, preoperative hypermobility, and >7 levels fused (AUC: 0.89). A predictive model for Sym versus Asym pts yielded an AUC of 85% and included being frail, having a TS-CL>20, and a PI>46.3. Controlling for BL deformity and disability, Sym pts had greater cSVA(4-8cm: 47.6%vs 27%) and were more maligned according to their SRS-SVA (0.1[0.76-0.02]) than non DJK pts at 1Y (all p<0.05). Despite their symptomatology and higher re-operation rate, outcomes equilibrated in the Sym cohort at 1Y following revision.
CONCLUSION(S): Overall 32.2% cervical deformed patients suffered from DJK most of which were clinically significant. Severe symptomatic DJK can be predicted with high reliability using combined determinants of baseline spinal cord dysfunction, mobility, frailty, and surgical factors including end levels, number of levels fused and use of a combined approach. It can be further distinguished from asymptomatic occurrences by taking into account pelvic incidence and baseline cervicothoracic deformity severity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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PURPOSE/OBJECTIVE:Coronal malalignment (CM) causes pain, impairment of function and cosmetic problems for adult spinal deformity (ASD) patients in addition to sagittal malalignment. Certain types of CM are at risk of insufficient re-alignment after correction. However, CM has received minimal attention in the literature compared to sagittal malalignment. The purpose was to establish reliability for our recently published classification system of CM in ASD among spine surgeons. METHODS:Fifteen readers were assigned 28 cases for classification, who represented CM with reference to their full-length standing anteroposterior and lateral radiographs. The assignment was repeated 2 weeks later, then a third assignment was done with reference to additional side bending radiographs (SBRs). Intra-, inter-rater reliability and contribution of SBRs were determined. RESULTS:Intra-rater reliability was calculated as 0.95, 0.86 and 0.73 for main curve types, subtypes with first modifier, and subtypes with two modifiers respectively. Inter-rater reliability averaged 0.91, 0.75 and 0.52. No differences in intra-rater reliability were shown between the four expert elaborators of the classification and other readers. SBRs helped to increase the concordance rate of second modifiers or changed to appropriate grading in cases graded type A in first modifier. CONCLUSIONS:Adequate intra- and inter-rater reliability was shown in the Obeid-CM classification with reference to full spine anteroposterior and lateral radiographs. While side bending radiographs did not improve the classification reliability, they contributed to a better understanding in certain cases. Surgeons should consider both the sagittal and coronal planes, and this system may allow better surgical decision making for CM.

PURPOSE/OBJECTIVE:Analysis of interactions of spinal alignment metrics may uncover novel alignment parameters, similar to PI-LL. This study utilized a data-driven approach to hypothesis generation by testing all possible division interactions between spinal alignment parameters. METHODS:This study was a retrospective cohort analysis. In total, 1439 patients with baseline ODI were included for hypothesis generation. In total, 666 patients had 2-year postoperative follow-up and were included for validation. All possible combinations of division interactions between baseline metrics were assessed with linear regression against baseline ODI. RESULTS:From 247 raw alignment metrics, 32,398 division interactions were considered in hypothesis generation. Conceptually, the TPA divided by PI is a measure of the relative alignment of the line connecting T1 to the femoral head and the line perpendicular to the sacral endplate. The mean TPA/PI was 0.41 at baseline and 0.30 at 2 years postoperatively. Higher TPA/PI was associated with worse baseline ODI (p < 0.0001). The change in ODI at 2 years was linearly associated with the change in TPA/PI (p = 0.0172). The optimal statistical grouping of TPA/PI was low/normal (≤ 0.2), medium (0.2-0.4), and high (> 0.4). The R-squared for ODI against categorical TPA/PI alone (0.154) was directionally higher than that for each of the individual Schwab modifiers (SVA: 0.138, PI-LL 0.111, PT 0.057). CONCLUSION/CONCLUSIONS:This study utilized a data-driven approach for hypothesis generation and identified the spino-pelvic ratio (TPA divided by PI) as a promising measure of sagittal spinal alignment among ASD patients. Patients with SPR > 0.2 exhibited inferior ODI scores. LEVEL OF EVIDENCE/METHODS:III.

BACKGROUND CONTEXT: For surgical adult spinal deformity (ASD) patients, determining optimal restoration of alignment and spinal shape is an active area of research. Complex corrective measures taken are in ASD. Incidence of specific alignment outcomes has yet to be investigated in each of the complex realignment ideals. PURPOSE: Assess alignment outcomes (pelvic nonresponse [PNR], PJK, postop cervical deformity [CD]) following ASD-corrective surgery in the context of correction relative to various alignment schemas. STUDY DESIGN/SETTING: Retrospective cohort study of prospective ASD database. PATIENT SAMPLE: A total of 468 ASD patients. OUTCOME MEASURES: PNR, PJK, postop CD.
METHOD(S): ASD patients with preop, 6-week postop (6W), and 2-year postop (2Y) radiographic data included. PNR: 10-year mismatch (undercorrection; unimproved) from a patient's age-adjusted PT at 6W and maintained at 2Y. Pelvic responder (PR): PT +/-10 match age-adjusted goals. Patients were stratified by incremental additions of corrective alignment schemas: (a) improvement in Schwab SVA, (b) matching age-adjusted PI-LL, (c) match postop "ideal" and "theoretical" Roussouly, (d) improvement in proportionality spinal score at 6W. PNR, PJK, and CD development by 2Y were compared within groups, as well as simultaneous improvement/match of the suggested corrective measures (exclusively). In a subanalysis, patients were stratified by severity of baseline PT, low (<20degree), moderate (20-30degree), and severe (>30degree) to determine which alignment schema is necessary to achieve less PNR, PJK and postop CD.
RESULT(S): A total of 468 patients (56.3 yrs, 76.5% F; 25.6% PNR, 40.6% PR) met inclusion criteria. Rates of postop PJK (PNR:49.2% vs PR:59.5%) and CD (18.3% vs 25.8%) were significantly less in the PNR group, p<0.05. Sole improvement in Schwab SVA (73.2%) did not impact PNR, PJK or CD (p>0.050). Undercorrected age-adjusted PI-LL presented with more PNR (60.1%), whereas overcorrected had increased PJK (68.2%), p<0.001. Matching Roussouly at 6W decreased PNR (17.8% vs mismatch:42.3%, p=0.002). 6W proportional spine, had lower rates of PNR (19.7%, severely disproportioned: 58.8%, p<0.001), with postop moderately disproportioned GAP with highest rates of PJK (p=0.010). Incremental addition of alignment schemas was assessed for effect on malalignment outcomes. Schwab and age-adjusted use (20.9%) had less incidence of PNR (28.6% vs 38.7%) than just Schwab. Addition of the Roussouly (18.3%) presented with less PNR (20% vs 30.4%) and PJK (38.5% vs 60.3%) than only Schwab & age-adjusted. Lastly, addition of proportion (16.7%) had 0% occurrence of PNR and CD. Stratifying by baseline PT severity, the low group demonstrated the least incidence of PNR (7.7%) and CD (10.3%) and PJK (41.3%) when matching theoretical Roussouly at 6W (all p<0.050). This remained the same for moderate PT for PNR and PJK, except Schwab improvement decreased postop CD occurrence (21.2%, p=0.049). Severe PT assessment determined PNR (20%), PJK (37.5%) and CD (19.4%) were the lowest with improvement of proportion at 6W (p<0.050).
CONCLUSION(S): Following ASD corrective surgery, 25.6% of patients showed residual pelvic malalignment, qualifying as pelvic nonresponders. Use of complex realignment schemas (SRS-Schwab, age-adjusted, Roussouly shape, GAP) decreased rates of pelvic nonresponse, PJK and postop cervical deformity development. Severe (>30degree) baseline pelvic tilt requires particular emphasis of proportionality in addition to other realignment ideals. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT/BACKGROUND:Considerable debate exists regarding the optimal surgical approach for adult spinal deformity (ASD). It remains unclear which approach, posterior-only or combined anterior-posterior (AP), is more cost-effective. Our goal is to determine the 2-year cost per quality-adjusted life year (QALY) for each approach. PURPOSE/OBJECTIVE:To compare the 2-year cost-effectiveness of surgical treatment for ASD between the posterior-only approach and combined AP approach. STUDY DESIGN/METHODS:Retrospective economic analysis of a prospective, multicenter database PATIENT SAMPLE: From a prospective, multicenter surgical database of ASD, patients undergoing 5 or more level fusions through a posterior-only or AP approach were identified and compared. METHODS:QALYs gained were determined using baseline, 1-year, and 2-year post-operative Short Form 6D. Cost was calculated from actual, direct hospital costs including any subsequent readmission or revision. Cost-effectiveness was determined using cost/QALY gained. RESULTS:The AP approach showed significantly higher index cost than the posterior-only approach ($84,329 vs $64,281). This margin decreased at 2-year follow-up with total costs of $89,824 and $73,904, respectively. QALYs gained at two years were similar with 0.21 and 0.17 in the posterior-only and the AP approaches, respectively. The cost/QALY at two years after surgery was significantly higher in the AP approach ($525,080) than in the posterior-only approach ($351,086). CONCLUSIONS:We assessed 2-year cost-effectiveness for the surgical treatment through posterior-only and AP approaches. The posterior-only approach is less expensive both for the index surgery and at 2-year follow-up. The QALY gained at 2-years was similar between the two approaches. Thus, posterior-only approach was more cost-effective than the AP approach under our study parameters. However, both approaches were not cost-effective at 2-year follow-up.

BACKGROUND CONTEXT: Revision surgery is often necessary for adult spinal deformity (ASD) patients. Satisfaction with management is an important component of HRQOL. PURPOSE: We hypothesized that patients who underwent multiple revision surgeries following adult spinal deformity correction would exhibit lower satisfaction scores. STUDY DESIGN/SETTING: Retrospective cohort study of a prospectively collected multicenter database of ASD patients. PATIENT SAMPLE: A total of 668 patients undergoing ASD surgery and eligible for minimum 2-year follow-up were included. OUTCOME MEASURES: SRS-22r satisfaction score.
METHOD(S): Visits were stratified by occurrence prior to the index surgery (period 0), after the index surgery only (period 1) (ie, never underwent revision or had not yet undergone revision), after first revision only (period 2), and after second revision only (period 3). Patients were further stratified by prior spine surgery before their index surgery. SRS-22r satisfaction scores were evaluated at all periods using multiple linear regression adjusting for age, gender, and CCI.
RESULT(S): In total, 46.6% had prior spine surgery before their index surgery. The overall revision rate was 21.3%. among patients with no spine surgery prior to the index surgery, satisfaction increased from period 0 to 1 (2.8 to 4.3, p<0.0001), decreased after one revision from period 1 to 2 (4.3 to 3.9, p=0.0004), and decreased after a second revision from period 2 to 3 (3.9 to 3.3, p=0.0437). Among patients with spine surgery prior to the index procedure, satisfaction increased from period 0 to 1 (2.8 to 4.2, p<0.0001), and decreased from period 1 to 2 (4.2 to 3.8, p=0.0011). No differences in follow-up time from last surgery were observed between visits in periods 1, 2, and 3 (all p>0.3). among patients with multiple revisions, 40% experienced rod fracture, 40% PJK, and 33% pseudarthrosis.
CONCLUSION(S): ASD patients exhibit decreased satisfaction with subsequent revision. Among patients undergoing primary surgery in our database, this effect is additive for multiple revisions. These results have important implications for surgeons, patients, insurers, hospital administrators, and policymakers. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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