Faculty Bibliography

MINI: The ability of PROMIS to capture disability from cervical sagittal malalignment is unknown. Correlations between PROMIS domains and legacy outcome metrics with cervical sagittal alignment parameters were analyzed. PROMIS domains correlated strongly with legacy outcomes and PROMIS Pain Intensity correlated with worsening sagittal alignment in patients with cervical sagittal deformity.

STUDY DESIGN/METHODS:Cost-utility analysis OBJECTIVE.: To compare the cost utility of operative versus nonoperative treatment of adolescent idiopathic scoliosis (AIS) and identity factors that influence cost-utility estimates. SUMMARY OF BACKGROUND DATA/BACKGROUND:AIS affects 1% to 3% of children aged 10 to 16 years. When the major coronal curve reaches 50°, operative treatment may be considered. The cost utility of operative treatment of AIS is unknown. METHODS:A decision-analysis model comparing operative versus nonoperative treatment was developed for a hypothetical 15-year-old skeletally mature girl with a 55° right thoracic (Lenke 1) curve. The AIS literature was reviewed to estimate the probability, health utility, and quality-adjusted life years (QALYs) for each event. For the conservative model, we assumed that operative treatment did not result directly in any QALYs gained, and the health utility in AIS patients was the same as the age-matched US population mean. Costs were inflation-adjusted at 3.22% per year to 2015 US dollars. Costs and benefits were discounted at 3%. Probabilistic sensitivity analysis was performed using mixed first-order and second-order Monte Carlo simulations. Incremental cost utility ratio (ICUR) and incremental net monetary benefit were calculated. One-way sensitivity analyses were performed by varying cost, probability, and QALY estimates. RESULTS:Operative treatment was favored in 98.5% of simulations, with a median ICUR of $20,600/QALY (95% confidence interval, $20,500-$21,900) below the societal willingness-to-pay threshold (WTPT) of $50,000/QALY. The median incremental net monetary benefit associated with operative treatment was $15,100 (95% confidence interval, $14,800-$15,700). Operative treatment produced net monetary benefit across various WTPTs. Factors that most affected the ICUR were net costs associated with uncomplicated operative treatment, undergoing surgery during adulthood, and development of pulmonary complications. CONCLUSION/CONCLUSIONS:Cost-utility analysis suggests that operative treatment of AIS is favored over nonoperative treatment and falls below the $50,000/QALY WTPT for patients with Lenke 1 curves. LEVEL OF EVIDENCE/METHODS:2.

OBJECTIVEThe Patient-Reported Outcomes Measurement Information System (PROMIS) has become increasingly popular due to computer adaptive testing methodology. This study aims to validate the association between PROMIS and legacy outcome metrics and compare PROMIS to legacy metrics in terms of ceiling and floor effects and questionnaire burden.METHODSA retrospective review of an outcomes database was performed at a single institution from December 2016 to April 2017. Inclusion criteria were age > 18 years and a chief complaint of back pain or neck pain. The PROMIS computer adaptive testing Pain Interference, Physical Function (PF), and Pain Intensity domains; Oswestry Disability Index (ODI); Neck Disability Index (NDI); and visual analog scale (VAS) back, VAS leg, VAS neck, and VAS arm were completed in random order. PROMIS was compared to legacy metrics in terms of the average number of questions needed to complete each questionnaire and the score distributions in the lower and higher bounds of scores.RESULTSA total of 494 patients with back pain and 130 patients with neck pain were included. For back pain, ODI showed a strong correlation with PROMIS-PF (R = -0.749, p < 0.001), Pain Intensity (R = 0.709, p < 0.001), and Pain Interference (R = 0.790, p < 0.001) domains. Additionally, the PROMIS Pain Intensity domain correlated to both VAS back and neck pain (R = 0.642, p < 0.001 for both). PROMIS-PF took significantly fewer questions to complete compared to the ODI (4.123 vs 9.906, p < 0.001). When assessing for instrument sensitivity, neither survey presented a significant ceiling and floor effect in the back pain population (ODI: 0.40% and 2.63%; PROMIS-PF: 0.60% and 1.41%). In the neck pain cohort, NDI showed a strong correlation with PROMIS-PF (R = 0.771, p < 0.001). Additionally, PROMIS Pain Intensity correlated to VAS neck (R = 0.642, p < 0.001). The mean number of questions required to complete the questionnaire was much lower for PROMIS-PF compared to NDI (4.417 vs 10, p < 0.001). There were no significant differences found in terms of ceiling and floor effects for neck complaints (NDI: 2.3% and 6.92%; PROMIS-PF: 0.00% and 5.38%) or back complaints (ODI: 0.40% and 2.63%; PROMIS-PF: 1.41% and 0.60%).CONCLUSIONSPROMIS correlates strongly with traditional disability measures in patients with back pain and neck pain. For both back and neck pain, the PROMIS-PF required patients to answer significantly fewer questions to achieve similar granularity. There were no significant differences in ceiling and floor effects for NDI or ODI when compared with the PROMIS-PF instrument.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:The goals of this study were to (1) evaluate pre-operative bone quality assessment and intervention practice over time and (2) review the current evidence for bone evaluation in spine fusion surgery. SUMMARY OF BACKGROUND DATA/BACKGROUND:Deformity spine surgery has demonstrated improved quality of life in patients however its cost has made it controversial. If pre-operative bone quality can be optimized then potentially these treatments could be more durable however, at present, no clinical practice guidelines have been published by professional spine surgical organizations. METHODS:A retrospective cohort review was performed on patients who underwent a minimum five-level primary or revision fusion. Pre-operative bone quality metrics were evaluated over time from 2012 - 2017 to find potential trends. Sub-group analysis was conducted based on age, gender, pre-operative diagnosis, and spine fusion region. RESULTS:Patient characteristics including pre-operative rates of pseudarthrosis and junctional failure did not change. An increasing trend of physician bone health documentation was noted (p = 0.045) but changes in other metrics were not significant. A gender bias favored females who had higher rates of pre-operative DXA studies (p = 0.001), Vitamin D 25-OH serum labs (p = 0.005), Vitamin D supplementation (p = 0.022), calcium supplementation (p < 0.001), antiresorptive therapy (p = 0.016), and surgeon clinical documentation of bone health (p = 0.008) compared to men. CONCLUSION/CONCLUSIONS:Our spine surgeons have increased documentation of bone health discussions but this has not affected bone quality interventions. A discrepancy exists favoring females over males in nearly all pre-operative bone quality assessment metrics. Pre-operative vitamin D level and BMD assessment should be considered in patients undergoing long fusion constructs however the data for bone anabolic and resorptive agents has less support. Clinical practice guidelines on pre-operative bone quality assessment spine patients should be defined. LEVEL OF EVIDENCE/METHODS:4.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:The objective of this study was to examine associations of gabapentin use with inpatient postoperative daily pain scores and opioid use in children undergoing PSF for AIS. SUMMARY OF BACKGROUND DATA/BACKGROUND:Gabapentin use in posterior spinal fusion (PSF) postoperative pain management for adolescent idiopathic scoliosis (AIS) is increasingly common in order to decrease opioid use and improve pain control, though there is conflicting data on dosing and effectiveness to support this practice in real world settings. METHODS:Retrospective cohort study of children aged 10 to 21 years undergoing PSF for AIS between January 2013 and June 2016 at an urban academic tertiary care center. Adjuvant gabapentin exposure was defined as at least 15 mg/kg/d by postoperative day (POD) 1 with an initial loading dose of 10 mg/kg on day of surgery. Primary outcomes were daily postoperative mean pain score and opioid use [morphine milligram equivalents/kg/day(mme/kg/d)]. Secondary outcomes were short and long-term complications. RESULTS:Among 129 subjects (mean age, 14.6 y, 74% female, mean coronal cobb, 55.2 degrees), 24 (19%) received gabapentin. Unadjusted GABA exposure was associated with significantly lower opioid use on POD1 and 2 (49% and 31%mme/kg/d, respectively) and lower pain scores (14%) on POD2. Adjusting for preexisting back pain, preoperative coronal Cobb angle, and site, GABA use was associated with significantly lower mean pain scores on POD1 through POD3 (-0.68, P=0.01; -0.86, P=0.002; -0.63, P=0.04). Gabapentin use was also associated with decreased opioid use on POD1 and POD2 (-0.39mme/kg/d, P<0.001; -0.27, P=0.02). There was no difference in complications by gabapentin exposure. CONCLUSIONS:Addition of gabapentin as adjuvant therapy for adolescent PSF, beginning on day of surgery, is associated with improved pain scores and decreased opioid use in the first 48 to 72 hours postoperatively. LEVEL OF EVIDENCE/METHODS:This is a retrospective cohort study, classified as Level III under "Therapeutic Studies Investigating the Results of a Treatment."

This study sought to assess comorbidity profiles unique to early-onset-scoliosis (EOS) patients by employing cluster analytics and to determine the influence of isolated comorbidity clusters on perioperative complications, morbidity and mortality using a high powered administrative database. The KID database was queried for ICD-9 codes pertaining to congenital and idiopathic scoliosis from 2003, 2006, 2009, 2012. Patients <10 y/o (EOS group) were included. Demographics, incidence and comorbidity profiles were assessed. Comorbidity profiles were stratified by body systems (neurological, musculoskeletal, pulmonary, cardiovascular, renal). K-means cluster and descriptive analyses elucidated incidence and comorbidity relationships between frequently co-occurring comorbidities. Binary logistic regression models determined predictors of perioperative complication development, mortality, and extended length-of-stay (≥75th percentile). 25,747 patients were included (Age: 4.34, Female: 52.1%, CCI: 0.64). Incidence was 8.9 per 100,000 annual discharges. 55.2% presented with pulmonary comorbidities, 48.7% musculoskeletal, 43.8% neurological, 18.6% cardiovascular, and 11.9% renal; 38% had concurrent neurological and pulmonary. Top inter-bodysystem clusters: Pulmonary disease (17.2%) with epilepsy (17.8%), pulmonary failure (12.2%), restrictive lung disease (10.5%), or microcephaly and quadriplegia (2.1%). Musculoskeletal comorbidities (48.7%) with renal and cardiovascular comorbidities (8.2%, OR: 7.9 [6.6-9.4], p < 0.001). Top intra-bodysystem clusters: Epilepsy (11.7%) with quadriplegia (25.8%) or microcephaly (20.5%). Regression analysis determined neurological and pulmonary clusters to have a higher odds of perioperative complication development (OR: 1.28 [1.19-1.37], p < 0.001) and mortality (OR: 2.05 [1.65-2.54], p < 0.001). Musculoskeletal with cardiovascular and renal anomalies had higher odds of mortality (OR: 1.72 [1.28-2.29], p < 0.001) and extLOS (OR: 2.83 [2.48-3.22], p < 0.001). EOS patients with musculoskeletal conditions were 7.9x more likely to have concurrent cardiovascular and renal anomalies. Clustered neurologic and pulmonary anomalies increased mortality risk by as much as 105%. These relationships may benefit pre-operative risk assessment for concurrent anomalies and adverse outcomes. Level of Evidence: III - Retrospective Prognostic Study.

STUDY DESIGN/METHODS:Retrospective cohort study at a single institution. OBJECTIVE:To analyze the perioperative and postoperative outcomes of patients who underwent open transforaminal lumbar interbody fusion (O-TLIF) and bilateral minimally invasive (MIS) Wiltse approach TLIF (Wil-TLIF). SUMMARY OF BACKGROUND DATA/BACKGROUND:Several studies have compared Open TLIF to MIS TLIF, however, comparing the techniques using a large cohort of one-level TLIFs has not been fully explored. METHODS:We reviewed the charts of patients undergoing a single-level primary posterior lumbar interbody fusion between 2012 and 2017. The cases were categorized as Open TLIF (traditional midline exposure including lateral exposure of transverse processes) or bilateral paramedian Wiltse TLIF approach. Differences between groups were assessed by t-tests. RESULTS:227 patients underwent one-level primary TLIF (116 O-TLIF, 111 Wil-TLIF). There was no difference in age, gender, ASA or BMI between groups. Wil-TLIF had the lowest EBL (197 mL vs. 499 mL O-TLIF, p =  < .001), LOS (2.7 days vs. 3.6 days O-TLIF, p =  < .001), overall complication rate (12% vs. 24% O-TLIF, p = .015), minor complication rate (7% vs. 16% O-TLIF, p = .049), and 90-day readmission rate (1% vs. 8% O-TLIF, p = .012). Wil-TLIF was associated with the higher fluoroscopy time (83 sec vs. vs. 24 sec O-TLIF, p =  < .001). There was not a significant difference in operative time, intraoperative or neurological complications, extubation time, reoperation rate, or infection rate. CONCLUSIONS:In comparing Wiltse MIS TLIF to Open TLIF, the minimally invasive paramedian Wiltse approach demonstrated the lowest EBL, LOS, readmission rates and complications, but longer fluoroscopy times when compared to the traditional open approach. LEVEL OF EVIDENCE/METHODS:3.

STUDY DESIGN/METHODS:Retrospective analysis of Medicare claims and procedure details from a single institution participation in the Bundled Payments for Care Improvement (BPCI) program. OBJECTIVE:To analyze the effects of the BPCI program on patient outcome metrics and cost data. SUMMARY OF BACKGROUND DATA/BACKGROUND:The BPCI program was designed to improve the value of care provided to patients, but the financial consequences of this system remain largely unknown. We present two years of data from participation in the lumbar spine fusion bundle at a large, urban, academic institution. METHODS:In 2013 and 2014, all Medicare patients undergoing lumbar spine fusions for DGR 459 (spinal fusion except cervical with MCC) and 460 (without MCC) at our institution were enrolled in the BPCI program. We compared the BPCI cohort to a baseline cohort of patients under the same DRGs from 2009 to 2012 from which the target price was established. RESULTS:350 patients were enrolled into the BPCI program, while the baseline group contained 518 patients. When compared to the baseline cohort, length of stay decreased (4.58 +/- 2.51 vs 5.13 +/- 3.75; p = 0.009), readmission rate was unchanged, and discharges with HHA increased. Nonetheless, we were unable to effect an episode-based cost savings ($52,655 +/- 27,028 vs $48,913 +/- 24,764). In the larger DRG 460 group, total payments increased in the BPCI group ($51,105 +/- 26,347 vs $45,934 +/- 19,638, p = 0.001). Operative data demonstrated a more complex patient mix in the BPCI cohort. The use of interbody fusions increased from 2% to 16% (p < 0.001), and the percentage of complex spines increased from 23% to 45% (p < 0.001). CONCLUSIONS:Increased case complexity was responsible for increasing costs relative to the negotiated baseline target price. This payment system may discourage advancement in spine surgery due to the financial penalty associated with novel techniques and technologies. LEVEL OF EVIDENCE/METHODS:3.

STUDY DESIGN/METHODS:Observational cohort study of prospective database registry. OBJECTIVE:To determine the incidence of neurological complications in AIS patients undergoing surgical treatment with PO. SUMMARY OF BACKGROUND DATA/BACKGROUND:Despite the widespread use of Ponte Osteotomies (PO) in adolescent idiopathic scoliosis (AIS) correction, outcomes and complications in patients treated with this technique have not been well characterized. METHODS:A multicenter prospective registry of patients undergoing surgical correction of AIS was queried at 2-year follow up for patient demographics, surgical data, deformity characteristics and peri-operative complications. A neurological complication was defined as perioperative nerve root or spinal cord injury as identified by the surgeon. Patients were divided into those that underwent peri-apical PO and those without, and further stratified by Lenke curve classification into 3 groups (I-types 1 & 2, II- types 3, 4, 6, and III-type 5). Patients with- and without neurological complications were compared with respect to baseline demographics, surgical variables, curve types, fusion construct types (screws vs. hybrid), curve magnitude (coronal and sagittal Cobb), apical vertebral translation, and coronal- deformity angular ratios (C-DAR). RESULTS:Of 2210 patients included in the study, 1611 underwent PO. Peri-operative neurological complications occurred in 7 patients, with 6 in the PO group (0.37%) and 1 in non-PO group (0.17%) though this was not a statistically significant risk factor for peri-operative neurological injury (p = 0.45). Neuromonitoring alerts were recorded in 168 patients (7.6%: 9.3% PO group; 4.2% no-PO group (p < 0.001). Multivariate logistic regression analysis found PO and curve magnitude to be independent risk factors for intra-operative neuromonitoring alerts (p < 0.01). CONCLUSIONS:PO and curve magnitude were independent risk factors for intra-operative neuromonitoring alerts in surgical AIS correction. The effect of Ponte osteotomy on neurological complications remains unknown due to the low incidence of these complications. LEVEL OF EVIDENCE/METHODS:3.

STUDY DESIGN/METHODS:A retrospective analysis of a patient-reported outcomes database from a single institution from December 2016 to April 2017. OBJECTIVE:To validate the association of PROMIS with NDI in patients with neck pain and examine each instruments ability to capture concomitant arm pain and concomitant back pain. SUMMARY OF BACKGROUND DATA/BACKGROUND:PROMIS has been increasingly utilized and its computer adapted testing methodology improves assessment of pain and disability. However literature is lacking regarding how these instruments perform in neck pain patients with concomitant arm pain or back pain. METHODS:Inclusion criteria were age>18years and a primary complaint of neck pain. The NDI, VAS Back, Neck, Arm and Leg, and PROMIS Physical Function, Pain Intensity, and Pain Interference questionnaires were administered. Propensity score matching was performed to compare patients with high and low back and arm pain while controlling for neck pain. Bivariate correlations and independent samples t-tests were performed to assess linear relationships and compare back and arm pain groups with PROMIS. RESULTS:130 patients were included. NDI correlated strongly to PROMIS Physical Function (r = -0.771, p < 0.001), Pain Intensity (r = 0.605, p < 0.001), and Pain Interference (r = 0.786, p < 0.001). VAS Neck and Arm Pain also correlated to the PROMIS Pain Intensity instrument (VAS Neck: r = 0.642, p < 0.001; VAS Arm: r = 0.376, p < 0.001).Following matching for neck pain, the high and low back pain groups each included 32 patients. There were significant differences in PROMIS Physical Function when high and low back pain groups were compared (39.07 vs 43.68, p = 0.031). No significant difference was found for any outcome metric for high and low arm pain groups. CONCLUSIONS:PROMIS instruments are capable of characterizing pain and disability in patients with neck pain and are sensitive to disability in regions adjacent to the neck. LEVEL OF EVIDENCE/METHODS:3.