Faculty Bibliography

The aim of this study was to investigate the cost utility of treating non-frail versus frail or severely frail adult spinal deformity (ASD) patients. 79 surgical ASD patients >18 years with available frailty and ODI data at baseline and 2-years post-surgery (2Y) were included. Utility data was calculated using the ODI converted to the SF-6D. QALYs utilized a 3% discount rate to account for decline to life expectancy (LE). Costs were calculated using the PearlDiver database. ICER was compared between non-operative (non-op.) and operative (op.) NF and F/SF patients at 2Y and LE. When compared to non-operative ASD, the ICER was $447,943.96 vs. $313,211.01 for NF and F/SF at 2Y, and $68,311.35 vs. $47,764.61 for NF and F/SF at LE. Frail and severely frail patients had lower cost per QALY compared to not frail patients at 2Y and life expectancy, and had lower ICER values when compared to a non-operative cohort of ASD patients. While these results support operative correction of frail and severely frail patients, it is important to note that these patients are often at worse baseline disability, which is closely related to frailty scores, and have more opportunity to improve postoperatively. Furthermore, there may be a threshold of frailty that is not operable due to the risk of severe complications that is not captured by this analysis. While future research should investigate economic outcomes at extended follow up times, these findings support the cost effectiveness of ASD surgery at all frailty states.

BACKGROUND:Although epidural steroid injection (ESI) may provide pain relief for patients with degenerative spondylolisthesis in treatment regimens of up to 4 months, it remains unclear whether ESI affects crossover from nonoperative to operative management. METHODS:This retrospective cohort study analyzed 2 groups of surgical candidates with degenerative spondylolisthesis: those who received ESI within 3 months after enrollment (ESI group) and those who did not (no-ESI group). Annual outcomes following enrollment were assessed within operative and nonoperative groups (patients who initially chose or were assigned to surgery or nonoperative treatment) by using longitudinal mixed-effect models with a random subject intercept term accounting for correlations between repeated measurements. Treatment comparisons were performed at follow-up intervals. Area-under-the-curve analysis for all time points assessed the global significance of treatment. RESULTS:The study included 192 patients in the no-ESI group and 74 in the ESI group. The no-ESI group had greater baseline Short Form-36 (SF-36) Bodily Pain scores (median, 35 versus 32) and self-reported preference for surgery (38% versus 11%). There were no differences in surgical rates within 4 years after enrollment between the no-ESI and ESI groups (61% versus 62%). The surgical ESI and no-ESI groups also showed no differences in changes in patient-reported outcomes at any follow-up interval or in the 4-year average. Compared with the nonoperative ESI group, the nonoperative no-ESI group showed greater improvements in SF-36 scores for Bodily Pain (p = 0.004) and Physical Function (p = 0.005) at 4 years, Bodily Pain at 1 year (p = 0.002) and 3 years (p = 0.005), and Physical Function at 1 year (p = 0.030) and 2 years (p = 0.002). Of the patients who were initially treated nonsurgically, those who received ESI and those who did not receive ESI did not differ with regard to surgical crossover rates. The rates of crossover to nonoperative treatment by patients who initially chose or were assigned to surgery also did not differ between the ESI and no-ESI groups. CONCLUSIONS:There was no relationship between ESI and improved clinical outcomes over a 4-year study period for patients who chose or were assigned to receive surgery for degenerative spondylolisthesis. In the nonsurgical group, ESI was associated with inferior pain reduction through 3 years, although this was confounded by greater baseline pain. ESI showed little relationship with surgical crossover. LEVEL OF EVIDENCE/METHODS:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

There has been limited discussion as to whether spine surgery patients are benefiting from shorter in-patient hospital stays or if they are incurring higher rates of readmission and complications secondary to shortened length of stays. Included in this study were 237,446 spine patients >18yrs and excluding infection. Patients with Clavien Grade 5 complications in 2015 had the lowest mean time to readmission after initial surgery in all years at 12.44 ± 9.03 days. Pearson bivariate correlations between LOS ≤ 1 day and decreasing days to readmission was the strongest in 2016.). Logistic regression analysis found that LOS ≤ 1 day showed an overall increase in the odds of hospital readmission from 2012 to 2016 (2.29 [2.00-2.63], 2.33 [2.08-2.61], 2.35 [2.11-2.61], 2.27 [2.06-2.49], 2.33 [2.14-2.54], all p < 0.001).

STUDY DESIGN/UNASSIGNED:Retrospective cohort study of prospective patients undergoing minimally invasive lumbar fusion at a single academic institution. OBJECTIVE/UNASSIGNED:To assess differences in perioperative outcomes between primary and revision MIS (minimally invasive surgical) lumbar interbody fusion patients and compare with those undergoing corresponding open procedures. METHODS/UNASSIGNED:Patients ≥18 years old undergoing lumbar interbody fusion were grouped by surgical technique: MIS or open. Patients within each group were propensity score matched for comorbidities and levels fused. Patient demographics, surgical factors, and perioperative complication incidences were compared between primary and revision cases using means comparison tests, as appropriate. RESULTS/UNASSIGNED:< .05). CONCLUSIONS/UNASSIGNED:Clinical outcomes of revision MIS lumbar interbody fusion were similar to those of primary surgery. Additionally, MIS techniques were associated with less EBL, shorter LOS, and fewer perioperative complications than corresponding open revisions.

Study Design/UNASSIGNED:Retrospective review of single institution. Objective/UNASSIGNED:To assess the relationship between Patient-Reported Outcomes Measurement Information System (PROMIS) and Oswestry Disability Index (ODI) scores in thoracolumbar patients. Methods/UNASSIGNED:Included: Patients ≥18 years with a thoracolumbar spine condition (spinal stenosis, disc herniation, low back pain, disc degeneration, spondylolysis). Bivariate correlations assessed the linear relationships between ODI and PROMIS (Physical Function, Pain Intensity, and Pain Interference). Correlation cutoffs assessed patients with high and low correlation between ODI and PROMIS. Linear regression predicted the relationship of ODI to PROMIS. Results/UNASSIGNED:= 0.499) of the variance in Pain Intensity score. Conclusions/UNASSIGNED:There is a large amount of variability with PROMIS that cannot be accounted for with ODI. ODI questions regarding walking, social life, and lifting ability correlate strongly with PROMIS while sitting, standing, and sleeping do not. These results reinforce the utility of PROMIS as a valid assessment for low back disability, while indicating the need for further evaluation of the factors responsible for variation between PROMIS and ODI.

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

STUDY DESIGN/METHODS:Single institution retrospective clinical review. OBJECTIVE:To investigate the relationship between levels fused and clinical outcomes in patients undergoing open and minimally invasive surgical (MIS) lumbar fusion. SUMMARY OF BACKGROUND DATA/BACKGROUND:Minimally invasive spinal fusion aims to reduce the morbidity associated with conventional open surgery. As multilevel arthrodesis procedures are increasingly performed using MIS techniques, it is necessary to weigh the risks and benefits of multilevel MIS lumbar fusion as a function of fusion length. METHODS:Patients undergoing <4 level lumbar interbody fusion were stratified by surgical technique (MIS or open), and grouped by fusion length: 1-level, 2-levels, 3+ levels. Demographics, Charlson Comorbidity Index (CCI), surgical factors, and perioperative complication rates were compared between technique groups at different fusion lengths using means comparison tests. RESULTS:Included: 361 patients undergoing lumbar interbody fusion (88% transforaminal, 14% lateral; 41% MIS). Breakdown by fusion length: 63% 1-level, 22% 2-level, 15% 3+ level. Op-time did not differ between groups at 1-level (MIS: 233 min vs. Open: 227, P = 0.554), though MIS at 2-levels (332 min vs. 281) and 3+ levels (373 min vs. 323) were longer (P = 0.033 and P = 0.231, respectively). While complication rates were lower for MIS at 1-level (15% vs. 30%, P = 0.006) and 2-levels (13% vs. 27%, P = 0.147), at 3+ levels, complication rates were comparable (38% vs. 35%, P = 0.870). 3+ level MIS fusions had higher rates of ileus (13% vs. 0%, P = 0.008) and a trend of increased adverse pulmonary events (25% vs. 7%, P = 0.110). MIS was associated with less EBL at all lengths (all P < 0.01) and lower rates of anemia at 1-level (5% vs. 18%, P < 0.001) and 2-levels (7% vs. 16%, P = 0.193). At 3+ levels, however, anemia rates were similar between groups (13% vs. 15%, P = 0.877). CONCLUSION/CONCLUSIONS:MIS lumbar interbody fusions provided diminishing clinical returns for multilevel procedures. While MIS patients had lower rates of perioperative complications for 1- and 2-level fusions, 3+ level MIS fusions had comparable complication rates to open cases, and higher rates of adverse pulmonary and ileus events. LEVEL OF EVIDENCE/METHODS:3.

In the current value-based healthcare climate where spine surgery is shifting to the ambulatory setting, factors influencing postop length of stay (LOS) are important to surgeons and hospital administrators. Pre-op patient factors including diagnosis of radiculopathy and myelopathy have yet to be investigated in this context. Operative pts ≥ 18Y with primary diagnoses of cervical myelopathy (M), radiculopathy (R), or myeloradiculopathy (MR) were included and propensity score matched by invasiveness score (Mirza et al.). Top-quartile LOS was defined as extended. M&R patients were compared using Chi² & independent t-tests. Univariate tests assessed differences in preop patient and surgical data in M&R pts and extended/non-extended LOS. Stepwise regression analysis explored factors predictive of LOS. 718 operative pts (54.5 yrs, 41.1%F, 29.1 kg/m², mean CCI 1.11) included (177 M, 383 R, and 158 MR). After PSM, 345 patients remained (115 in each diagnosis). 102 patients had E-LOS (Avg: 5.96 days), 41 M patients (mean 7.1 days), 28 R (5.9 days), and 33 MR (4.6 days). Regression showed predictors of E-LOS in R pts (R²â€¯= 0.532, p = 0.043): TS-CL, combined and posterior approach, LIV, UIV, op time, Lactated Ringer's, postoperative complications. Predictors of E-LOS in M pts (R²â€¯= 0.230, p < 0.001): age, CCI, combined and posterior approach, levels fused, UIV, EBL, neuro and any postop complications. Predictors of E-LOS in MR patients (R²â€¯= 0.152, p < 0.001): age, kyphosis, combined approach, UIV, LIV, levels fused, EBL and op time. Independent of invasiveness, patients with a primary diagnosis of myelopathy, though older aged and higher comorbidity profile, had consistently longer overall postop LOS when compared to radiculopathy or myeloradiculopathy patients.

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

BACKGROUND CONTEXT: The efficacy of surgical intervention for central cord syndrome (CCS) is shown in the literature; however, it is unclear whether disparities in patient presentation and treatment exist between those who initially undergo operative treatment and those who delay operative treatment. PURPOSE: In a population of CCS patients, assess disparities in presentation and treatment between those undergoing immediate surgery and those who delay operative treatment. STUDY DESIGN/SETTING: Retrospective analysis of New York State Inpatient Database years 2004-2013. PATIENT SAMPLE: A total of 1,301 CCS patients (ICD-9 codes 952.03, 952.08, 952.13, 952.18). OUTCOME MEASURES: Time to surgery, length of stay (LOS).
METHOD(S): Patient-specific linkage codes allowed longitudinal tracking of inpatient stays within the study period. Demographics, comorbidities (Charlson Comorbidity Index [CCI]), complications, and surgical factors, including Mirza invasiveness score, were compared between CCS patients that initially underwent surgery (Initial) and patients that delayed operative treatment (Delayed) using Chi-squared tests and independent samples t-tests as appropriate. Similar tests assessed differences in demographics and comorbidity burden between nonoperative patients and surgical crossover patients.
RESULT(S): Included: 1,301 CCS patients (62+/-16 yrs, 27% female). Follow-up rate was 67.3%; mean follow-up time was 515+/-707 days. By level of CCS injury, 61.0% of patients were injured between C1 and C4, 59.2% between C5-C7, 1.0% between T1-T6, and 0.6% between T7-T12. Overall, 800 (61%) patients underwent surgical treatment (procedural breakdown: 80% fusion, 59% decompression, including 38% discectomy and 23% other decompression of the spinal canal). Of the surgical patients, 621 (78%) had surgery at first recorded hospital visit, while 179 (22%) experienced a delay before surgical treatment. For patients that delayed treatment, mean time to surgery was 203+/-358 days. Initial and Delayed patients did not differ in sex (p=0.109) or CCI (p=0.894), though Initial patients were younger than Delayed (60+/-15 yrs vs 63+/-13, p=0.016) and had lower rates of diabetes and valvular disease (both p<0.04). Initial patients underwent more invasive procedures than Delayed (5.1+/-2.6 vs 4.3+/-3.2, p=0.003), including higher rates of fusion (84% vs 71%, p<0.001), but not decompression: overall (59% vs 60%, p=0.816), discectomy (39% vs 35%, p=0.306), other canal decompression (22% vs 27%, p=0.175). LOS was longer for Initial patients (16+/-20 days vs 7+/-10, p<0.001), but complication rates did not differ (all p>0.05). Patients who delayed operative treatment did not differ from nonop patients in age (63+/-13 vs 63+/-17, p=0.802) or CCI (1.04+/-1.49 vs 1.06+/-1.49, p=0.923); however, Delayed patients had higher rates of diabetes (26% vs 18%, p=0.037), neurologic disorders (7% vs 1%, p<0.001), and valvular disease (6% vs 2%, p=0.026) than patients that remained nonoperative.
CONCLUSION(S): Although patients managed with initial surgical treatment of CCS had longer hospital stays and were treated with more invasive procedures, perioperative complications did not differ. Twenty-two percent of CCS patients crossed over from nonoperative to operative treatment, with a mean time to crossover of 203 days. Patients who crossed over to operative care were more comorbid than patients who remained nonoperative, indicating comorbidity burden may play a role in the decision to operate. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright