Faculty Bibliography

BACKGROUND:The Miller et al adult spinal deformity frailty index (ASD-FI) correlates with complication risk; however, its development was not rooted in clinical outcomes, and the 40 factors needed for its calculation limit the index's clinical utility. The present study aimed to develop a simplified, weighted frailty index for ASD patients METHODS: This study is a retrospective review of a single-center database. Component ASD-FI parameters contributing to overall ASD-FI score were assessed via Pearson correlation. Top significant, clinically relevant factors were regressed against ASD-FI score to generate the modified ASD-FI (mASD-FI). Component mASD-FI factors were regressed against incidence of medical complications, and factor weights were calculated from regression of these coefficients. Total mASD-FI score ranged from 0 to 21, and was calculated by summing weights of expressed parameters. Linear regression and published ASD-FI cutoffs generated corresponding mASD-FI frailty cutoffs: not frail (NF, <7), frail (7-12), severely frail (SF, >12). Analysis of variance assessed the relationship between frailty category and validated baseline measures of pain and disability at baseline. RESULTS:= .001). CONCLUSIONS:This study modifies an existing ASD frailty index and proposes a weighted, shorter mASD-FI. The mASD-FI relies less on patient-reported variables, and it weights component factors by their contribution to adverse outcomes. Because increasing mASD-FI score is associated with inferior clinical measures of pain and disability, the mASD-FI may serve as a valuable tool for preoperative risk assessment.

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.

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.

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 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.

BACKGROUND CONTEXT: Although epidural steroid injection (ESI) has been shown to provide adequate pain relief for degenerative spondylolisthesis patients in treatment regimens up to months, it remains unclear whether the use of ESI affects the rate of crossover from nonoperative to operative management. PURPOSE: Investigate the relationship between epidural steroid injections and rates of surgical crossover for degenerative spondylolisthesis patients. STUDY DESIGN/SETTING: Retrospective review of prospectively collected data from 13 spine centers. PATIENT SAMPLE: Degenerative spondylolisthesis patients from both the randomized and concurrent observational cohorts of the Spine Patient Outcomes Research Trial (SPORT). OUTCOME MEASURES: Primary: Surgical crossover rates. Secondary: health related quality of life outcome (HRQL) measures (SF-36, ODI, Sciatica and Leg Pain Bothersomeness Indices), self-reported improvement METHODS: Included: surgical candidates >18yrs with degenerative spondylolisthesis. Excluded: patients receiving ESI before enrollment. Those who received ESI within 3 months of enrollment (ESI) and those who did not (no-ESI) were compared for differences in baseline characteristics. Outcomes at 1-year, 2-year, 3-year, and 4-year intervals following enrollment were assessed within operative and nonoperative groups using longitudinal mixed-effect models with random subject intercept term to account for correlations between repeated measurements. Treatment comparisons were performed at follow-up intervals. Area under the curve analysis for all time points assessed global significance of treatment.
RESULT(S): Included: 266 patients (192 no-ESI, 74 ESI). Patient groups did not differ in age, sex, BMI, or comorbidity burden (all p>0.05). No-ESI had greater baseline SF-36 body-pain scores (38+/-20 vs 30+/-16, p=0.002) and self-reported surgical preference (38% vs 11%, p<0.001). There were no differences in surgical rates within 4-years of enrollment between no-ESI and ESI patients (61% vs 62%, p=0.97). Surgical ESI and no-ESI patients did not differ in op-time, blood loss, rates of decompression, multilevel fusion or levels decompressed (all p>0.05). Surgical ESI and no-ESI patients showed no differences in postoperative HRQL changes at any follow-up interval, or in 4-year average HRQL outcomes. Non-operative no-ESI patients showed greater 4-year average improvement in SF-36 body pain (no-ESI: 17.8, ESI: 7.8, p=0.004) and physical function (no-ESI: 13.1, ESI: 4.3, p=0.005) than non-operative ESI patients. These improvements in SF-36 body pain were greater for non-operative no-ESI patients at 1-year (p=0.002) and 3-years (p=0.005); improvements in SF-36 physical function were greater for non-operative no-ESI patients at 1-year (p=0.030) and 2-years (p=0.002). Of patients that were initially non-operative, there was no difference between ESI and no-ESI groups in surgical crossover rates (ESI: 52%, no-ESI: 39%, p=0.15). For operative patients, crossover rates to non-operative treatment did not differ between ESI and no-ESI groups (ESI: 23%, no-ESI: 16%, p=0.38).
CONCLUSION(S): For surgical degenerative spondylolisthesis patients, there was no relationship between ESI and improved clinical outcomes over a 4-year study. For nonoperative patients, ESI was associated with inferior pain reduction through 3 years of follow-up; however, this was confounded by higher levels of baseline pain. ESI showed little relationship with surgical crossover. FDA DEVICE/DRUG STATUS: Unavailable from authors at time of publication.
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BACKGROUND CONTEXT: Bariatric surgery for morbid obesity helps to address common comorbidity burdens, including decreasing rates of myocardial infarction and stroke. The increased mechanical stresses on the spine caused by morbid obesity predispose patients to various spinal pathologies and are concerning for spinal surgeons, with previous studies suggesting poorer outcomes than the general population. The effects of bariatric surgery on diminishing spinal complaints or symptoms have yet to be elucidated in the literature. PURPOSE: To assess the rate in which various spinal symptoms diminish after bariatric surgery. STUDY DESIGN/SETTING: Retrospective analysis of the prospectively collected New York State Inpatient Database (NYSID) years (2004-2013). PATIENT SAMPLE: A total of 4,351 patients who underwent bariatric surgery with at least one identified spinal diagnosis present before bariatric surgery. OUTCOME MEASURES: Time from bariatric surgery until disappearance of specific spinal complaint, percentage of unresolved spinal complaints with 2-year follow-up.
METHOD(S): Retrospective analysis of the prospectively collected (NYSID) years 2004-2013. Patient linkage codes allow identification of multiple and return inpatient stays within the time frame analyzed (720 days). Inclusion criteria were bariatrics surgery patients with one or more visits prior to and after bariatric procedure (excluding pts with <30 days f/u, spine surgery, or new post-bariatric spine pathology) for one of the following common cervical or lumbar spinal diagnoses, queried with ICD-9CM codes: herniation, stenosis, spondylosis, disc degeneration, and spondylolisthesis. Time from bariatric surgery until the patient's respective spinal diagnosis was no longer present was considered resolution of spinal symptoms. Kaplan-Meier survivorship curves assessed rates of resolution within each spinal diagnosis cohort.
RESULT(S): A total of 4,351 bariatric surgery pts with a preop spinal diagnosis by ICD-9 were analyzed. Lumbar pts: 1,049 had stenosis, 774 spondylosis, 648 degeneration, 249 spondylolisthesis, 72 disc herniation. Cervical pts: 581 disc herniation, 376 had stenosis, 366 spondylosis, 236 degeneration. Cumulative resolution rates at 90-day, 180-day, 360-day, and 720-day follow-up were as follows: lumbar stenosis (48%,67.6%,79%,91%), lumbar herniation (61%,77%,86%,93%), lumbar spondylosis (47%,65%,80%,93%), lumbar spondylolisthesis (37%,58%,70%,87%), lumbar degeneration (37%,56%,72%,86%). By cervical region: cervical stenosis (48%,70%,84%,94%), cervical herniation (39%,58%,74%,87%), cervical spondylosis (46%, 70%,83%, 94%), cervical degeneration (44%,64%,78%,89%). Lumbar herniation pts saw significantly higher 90d-resolution than cervical herniation pts (p<0.001). Cervical vs lumbar degeneration resolution rates did not differ @90d (p=0.058), but did @180d(p=0.034). Cervical and lumbar stenosis resolution was similar @90d & 180d, but cervical showed greater resolution by 1 year (p=0.036).
CONCLUSION(S): Over 50% of bariatric patients diagnosed with a cervical or lumbar pathology before weight-loss surgery no longer sought inpatient care for their respective spinal diagnosis by 180 days postop. Lumbar herniation had significantly higher resolution than cervical herniation by 90d, whereas cervical degeneration and stenosis resolved at higher rates than corresponding lumbar pathologies by 180d and 1-year follow-up, respectively. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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