Faculty Bibliography

BACKGROUND CONTEXT: Many different risk factors for PJK have been identified in those having surgery for ASD. The presence of CF prior to thoracolumbar fusion as a risk factor in this patient population has not been investigated. PURPOSE: To investigate if prior cervical fusion would be a risk factor for PJK when upper thoracic UIV was selected. STUDY DESIGN/SETTING: Retrospective review of prospective multicenter database. PATIENT SAMPLE: Inclusion: age >18 and one of the following inclusion criteria was queried: PI-LL >10, PT >20, Max Cobb>10, SVA > 5 cm. OUTCOME MEASURES: Development of PJK; HRQOL include NRS back and leg, ODI, SRS-22, EQ5D METHODS: Inclusion: age >18 and one of the following inclusion criteria was queried: PI-LL >10, PT >20, Max Cobb>10, SVA > 5 cm. 1023 patients were identified and grouped as CF (prior CF; n=101) and NoCF (n=922). Patients with 5 or fewer levels of CF and those without further cervical spine surgery at final follow-up were included (cASD= 86; ASD= 910). After initial analysis propensity matching was performed controlling for: age, BMI, pre-op alignment (PI, PI-LL, TPA, SVA), change in alignment (PI-LL), and UIV/LIV.
RESULT(S): Among 996 patients the CF group was older (64 v 60; p<0.000), higher BMI (29.7 v 28; p<0.014), with equal gender distribution. PJK at 1 year was 34.9% (n=30) in CF and 34.7% (n=316) in NoCF. All patients included had a minimum of four segments unfused between CF and TL fusion. No differences were found between groups when stratifying by UIV (UT=upper thoracic; LT=Lower thoracic; L=lumbar). Radiographically CF had worse preop deformity (PI-LL 21.3 v 17.2; TPA 27.3 v 23.6; SVA 90.6 v 68.5; p<0.05), with no difference in postop alignment between groups. CF was more likely to have LT UIV (61.6% v 46%; p=0.045) and fusion to the ilium (93% v 81%; p=0.005). After propensity matching 79 patients were included in each group. CF had 68 patients with ACDF, 5 patients with PSF, and 6 patients with A/PSF. There was no difference in the rate of PJK (39.2 v 34.2%), PJK magnitude (13.4 v 13.7) or change in PJK angle (10.1 v 10.4). PJK rate and magnitude are not different by UT or LT as UIV.
CONCLUSION(S): The presence of CF is not associated with the development of PJK or PJK magnitude in this propensity matched cohort. All CF patients had a minimum of four segments unfused between the CF and the TL fusion which may act as a buffer and be protective of PJK. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Surgical intervention of the cervical spine is a challenging procedure that can present postoperative complications such as dysphagia, swelling, and reoperations. However, the risk of reoperation can possibly be mitigated with the use of biologics to enhance fusion. There is paucity in the literature on long-term incidence of reoperations after application of BMP during ACDF. PURPOSE: To evaluate if bone morphogenetic protein usage during anterior cervical discectomy and fusion will decrease reoperation rates. STUDY DESIGN/SETTING: Retrospective review of the PearlDiver database between 2006-2014. PATIENT SAMPLE: Matched cohort of 35,544 ACDF patients. OUTCOME MEASURES: Reoperations.
METHOD(S): Patients undergoing an anterior cervical discectomy and fusion between the years 2006-2014 were isolated in the PearlDiver database. Patients receiving BMP operatively and a control with no BMP were matched for baseline demographics including age, sex, and comorbidities. A Kaplan Meier Survival analysis assessed five-Year Reoperation-Free Survival between BMP patients and controls. Statistical significance was set to p<0.05.
RESULT(S): A matched cohort of 35,544 ACDF patients was isolated. A total of 17,772 patients received BMP while undergoing cervical fusion and 17,772 did not receive any BMP during surgery. Patients did not differ in age, sex or comorbidities (p>0.05). Kaplan Meier survival analysis showed patients receiving BMP during cervical fusion were significantly more likely to remain reoperation free five years after index surgery (p<0.05). Overall, 91.3% of BMP patients remained reoperation free at five years.
CONCLUSION(S): For patients receiving bone morphogenetic protein during anterior cervical discectomy and fusion, Kaplan-Meier survival analysis following five years post index surgery had showed a 91.3% reoperation-free survivorship. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Complications occur commonly following adult spinal deformity surgery. Length of stay may be influenced by the type of surgical intervention, and/or by postoperative complication and the intervention required to treat that complication. PURPOSE: To understand the impact of complications and their intervention severity on the incremental increase in length of stay. STUDY DESIGN/SETTING: Retrospective cohort study of prospective ASD database. PATIENT SAMPLE: The study included 1418 adult spinal deformity patients. OUTCOME MEASURES: Neurologic complications, HRQL scores.
METHOD(S): ASD patients (>18yrs, scoliosis >=20degree, SVA >=5cm, PT >=25degree and/or TK >60degree). Complications were classified based on complication type, and intervention severity (grade 0, no intervention, Grade 1 minimal intervention (medication change, etc), Grade 2 moderate (cardioversion, chest tube, etc), grade 3 major intervention (return to OR).
RESULT(S): Of the 1418 patients included, 901 had at least one complication event, with 568 with a complication before discharge. Three hundred and six had an event that required a reoperation and 275 were readmitted for their event. When determining LOS, a baseline was established that was influenced by the type of surgery and placed into three groups based on osteotomy (O) and interbody use (I); Group 1 (n408): 0% O, 75% I, LOS=7.9, Group 2 (n374): 100% O, 0% I, LOS=11.9, Group 3 (n595) 100% O and I, LOS=11.2. Having a complication event prior to discharge led to an increase of 1-4 days for each group (p<0.01). This was true for every complication, regardless of type, but was worse for renal and pneumonia. The increase in LOS was most driven by the intervention required. No intervention had an LOS of 6.9, Grade 1 +1.2 days, Grade 2, +1.8 days, Grade 3 +2.5 days. Using the sum of a weighted intervention score (SUM=1*#grade1 + 2*#grade2 + 3*#grade3), we can even more accurately predict the incremental increase in LOS. This occurs until a weighted score of 7 which accurately predicts an increase of 7.5 days.
CONCLUSION(S): Length of stay following ASD is predicted by the type of surgical intervention, and postoperative complication profile. Additional days are most predicted by the type of complication and by intervention severity. A weighted intervention score can predict the additional LOS and is useful to help understand the impact of complications. 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.

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: Neurologic complications following adult spinal deformity (ASD) are common and may play a role in the outcomes for our patients. Neurologic complications may include radiculopathy, sensory deficit or motor weakness. The impact that these specific complications have on HRQL is unknown. PURPOSE: Neurologic complications are common following ASD. Understanding their impact on Health-related quality of life (HRQL) measures is critical. STUDY DESIGN/SETTING: Retrospective cohort study of prospective ASD database. PATIENT SAMPLE: Retrospective cohort study, 733 patients. OUTCOME MEASURES: Neurologic complications, HRQL scores.
METHOD(S): ASD patients (>18yrs, scoliosis >=20degree, SVA >=5cm, PT >=25degree and/or TK >60degree). Inclusion criteria was HRQL at baseline (BL) and 1 year, and lower extremity motor score (LEMS) at BL, 6-week and 1-year ODI, SRS22r and SF36 were determined at BL and 1yr LEMS was calculated from 0-50, with 50 designated as normal motor function. Patients were divided into 4 groups: pLEMS (perfect, no deficit), dLEMS (new postop deficit that returned to normal at 1 year), iLEMS (deficit improved from abnormal baseline), and wLEMS (new postop deficit persistent at one year).
RESULT(S): A total of 733 patients were eligible, with 95 (12.96%) reporting neurologic complications (NC). Impact of any NC vs no complication at 1yr was significant for ODI (5.1), PCS (3.6) and SRSpain (0.2) at 1 year (p<0.001 all). For NC vs any other complication, there was still a decrease in ODI (3.9) and PCS (2.4) at 1 year (p<0.01). NC subtype: radiculopathy caused worse outcomes for (4.3) and SRS pain (0.3) (p<0.05), sensory deficit caused worse SRSmental (0.5) (p<0.05), but no HRQL change was detected for motor deficit at 1 year. PLEMS (456/733) had improvement in all HRQL, and these improvements were not different with or w/o NC, or non-NC. Compared to pLEMS w/o complication, dLEMS (62/733) and iLEMS (147/733) were statically similar, however wLEMS (68/733) had worse ODI (7.1), SRStotal (0.3), activity (0.3), mental (0.3), pain (0.3) (p<0.05 all).
CONCLUSION(S): Neurologic complications that occur following ASD have a significant effect on HRQLs. The magnitude of effect is driven by radiculopathy and by lower extremity motor score. LEMS scores that remain normal, return back to normal or improve have similar outcomes, while patients that have continued weakness remain statistically worse at 1 year. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Circumferentially minimally invasive (cMIS) correction techniques of adult scoliosis have advanced, but it is unclear how outcomes compare to open correction. PURPOSE: To compare health related quality of life (HRQL) measures and surgical parameters between the two modalities. STUDY DESIGN/SETTING: Retrospective review of prospective multicenter adult spinal deformity database. PATIENT SAMPLE: Inclusion criteria are age >18, and one of the following: PT>25, PI-LL>10, or SVA>5 cm. OUTCOME MEASURES: NRS leg, ODI, SF-12, EQ5D, SRS-22.
METHOD(S): A prospective database was retrospectively reviewed. Inclusion criteria were age >18, and one of the following: PT>25, PI-LL>10, or SVA>5 cm. Patients were grouped as cMIS (percutaneous screws) or OPEN. Propensity matching was used to create two equal groups controlling for: age, BMI, preop (PI-LL, PI, TPA), and number of posterior levels fused.
RESULT(S): A total of 154 (77 cMIS, 77 OPEN) patients were included after matching for age, BMI, PI-LL (15 vs 17degree), PI (54degree vs 54degree), TPA (21degree vs 22degree), and mean number of levels fused (6 vs 6), for cMIS and OPEN, respectively. 3-column osteotomies were excluded. Baseline and postop ODI, SRS total, EQ5D were not different between MIS and OPEN (p=0.50, 0.45, 0.33). Maximum Cobb angles were similar for OPEN and cMIS, respectively, at baseline (26.3degree, 25.9degree, p=0.85) and at 1-yr postop (17.5degree, 15.0degree, p=0.17). Patients reaching minimal clinically important difference (MCID) were 58.3% for OPEN and 64.4% for cMIS (p=0.31) at 1 year. At 1 year, no difference was observed between PI-LL, SVA, PT, or Cobb (p=0.71, 0.46, 0.9, 0.20). OPEN vs MIS had greater EBL (1.36L vs 0.524L, p<0.05), fewer levels of interbody fusion (1.87 vs 3.46, p<0.05), but shorter OR time (356 vs 452min, p=0.003). Revision surgery rates between the two cohorts were not different (p=0.097).
CONCLUSION(S): When comparing cMIS to OPEN adult scoliosis correction with propensity matching, HRQL improvement, spino-pelvic parameters, revision surgery rates, and patients reaching MCID were not different between cohorts. However, cMIS had lower blood loss with comparable results in well-selected patients, but longer OR time. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Opioid use prior to surgery is associated with worse postop outcomes. Little is known regarding the economic impact that preop opioid use has upon patient preferred health state, quality adjusted life years (QALYs) and the cost/QALY of surgical treatment for adult spinal deformity (ASD). PURPOSE: Compare the health state preference values, QALYs, and cost/QALY for operatively treated ASD patients that used opioids vs did not use opioids prior to surgery. STUDY DESIGN/SETTING: Cost/QALY analysis of operatively treated patients identified from a prospective, multi-center ASD study. PATIENT SAMPLE: Propensity score matched (PSM) cohorts of patients that used opioids (OPIOID) vs nonusers (NON) prior to ASD surgery, at 1- and minimum 2-year follow up. OUTCOME MEASURES: Short Form-36v2 questionnaire (SF-36), SF6D derived from SF-36, hospital costs for operative treatment of ASD based on CMS DRG reimbursements, QALYs, cost/QALY for index surgery, perioperative complications, and 1- and 2-year postop opioid use.
METHOD(S): ASD patients (age>18 years) enrolled into a prospective multicenter ASD database were divided into preop opioid (OPIOID) vs nonopioid (NON) users. PSM was performed to control for confounding demographic, radiographic, and surgical variables. Preop, 1-year, and minimum 2-year postop SF6D values obtained, 1- and 2-year post QALYs were calculated using SF6D change from baseline, hospital costs at the time of index surgery were calculated using CMS DRG reimbursements adjusted for inflation to 2019 US dollars, cost/QALY evaluated at 1- and 2-years postop, perioperative complications, and 1- and 2-year postop opioid use was evaluated for OPIOID vs NON.
RESULT(S): DRG data was available for 182/262 patients meeting inclusion criteria. Following PSM, preoperative demographics, radiographic parameters, surgical treatment, and mean follow up (3.4 vs 3.3 years) were similar for OPIOID (n=68) vs NON (n=114), respectively (p>0.05). OPIOID had longer ICU (49 vs 23 hours) and hospital stay (9.7 vs 6.8 days) than NON, respectively (p<0.05). SF6D was worse for OPIOID at preop (0.521 vs 0.598), 1-year (0.613 vs 0.749), and 2-years postop (0.626 vs 0.749) than NON, respectively (p<0.05). QALYs were worse at 1- (0.567 vs 0.674) and 2-years postop (0.674 vs 0.825) for OPIOID vs NON, respectively (p<0.05). Cost of care at index surgery was greater for OPIOID ($83,363.02) vs NON ($70,281.17). Cost/QALY was higher for OPIOID at 1-year ($150,294.51vs $107,947.19) and 2-years postoperative ($69,615.78 vs $48,761.14) than NON (p<0.05). Perioperative complications were similar for OPIOID vs NON (p>0.05). Continued opioid use at 2-years postop was greater for OPIOID (52.4%) vs NON (8.7%; p>0.05).
CONCLUSION(S): Opioid use prior to ASD surgery is associated with worse patient perceived health state and greater costs to society. After controlling for patient demographics, deformity magnitude, and type of surgery, OPIOID had greater cost of care, despite similar perioperative complication rates. At 2-years postop both OPIOID and NON demonstrated cost effectiveness of index surgery (cost/QALY<$100,000), however the residual cost to society was $21,300 greater for OPIOID vs NON. Over 52% of OPIOD had continued opioid usage at 2-years postop compared to 8.7% of NON. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Emphasis has been placed upon reducing perioperative complications in spinal operations, of which cardiac complications remain among the most devastating for patients. Myocardial infarction (MI), along with its predictive factors, has been an understudied complication. PURPOSE: To assess the incidence and risk factors for perioperative myocardial infarctions in spine surgery patients. STUDY DESIGN/SETTING: Retrospective case control study PATIENT SAMPLE: A total of 196,086 surgical spine patients OUTCOME MEASURES: Predictors of MI following surgical spine intervention METHODS: A patient was categorized as having sustained a postsurgical MI in this study if it occurred intraoperatively or within 30 days of surgery, manifested by documentation of ECG changes accordingly: ST elevation >1mm in two or more contiguous leads, new left bundle branch, new Q-wave in two or more contiguous leads, or new elevation in troponin greater than three times upper level of the reference range. The relationship between MI and non-MI spine patients was assessed using chi-squared and independent samples t-tests, as appropriate. Descriptive statistics, including frequency counts for categorical variables and means and standard deviations, were calculated to summarize demographics and clinical profiles such as spinal diagnoses and comorbidity. Univariate/multivariate analyses were run to assess predictive factors of MI in spine surgery patients. Logistic regression with stepwise model selection was employed to create a model to predict MI occurrence.
RESULT(S): Of 196,523 patients (57.1+/-14.2 years, 48% female, 30.4+/-6.5 kg/m2) undergoing elective spine surgery, 436 patients had an acute MI intraoperatively or within 30 days postoperatively (Spine-MI) (69.07+/-10.4 years, 42% female, 30.39+/-6.22 kg/m2). Incidence of MI did not change significantly from 2010 to 2016 (0.2% to 0.3%, p=0.298). Spine-MI patients underwent significantly more fusions than elective spine surgical patients who did not have an MI (73.6% vs 58.4%, p<0.001), with an average of 1.03 levels fused. Spine-MI patients also had significantly more Smith-Peterson osteotomies (5.0% vs 1.8%, p<0.001) and three-column osteotomies (0.9% vs 0.2%, p<0.001), but had far fewer decompression-only procedures (26.4% vs 41.6%, p<0.001). Overall, patients who developed a perioperative MI underwent more revisions compared to all elective spine surgery patients (5.3% vs 2.9%, p=0.003). Spine-MI patients had significantly greater invasiveness scores (3.41 vs 2.73, p<0.001) and total operative time (211.6 vs 147.3 min, p<0.001). The average number of post-operative days until developing an MI was 5.27 days; 9.9% day of operation, 50.8% 1-3 days after, 20.8% 4-7 days 10.9% 8-15 days, 7.6% 16-30 days. Mortality rate for Spine-MI patients was 4.6% versus 0.05% in the entire elective spine surgical population (p<0.001). Multivariate modeling for Spine-MI predictors yielded an AUC of 83.7%, and included history of diabetes mellitus, cardiac arrest and peripheral vascular disease, past blood transfusion, dialysis-dependence, high preoperative platelet count, superficial surgical site infection and days from operation to discharge.
CONCLUSION(S): A model with good predictive capacity to predict MI after spine surgery now exists. Predictive modeling of myocardial infarction following spine operations can aid in risk-stratification of patients, consequently improving preoperative patient counseling and optimization in the peri-operative period. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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