Faculty Bibliography

BACKGROUND CONTEXT: Proximal junctional failure (PJF) is a common and particularly adverse complication of adult spinal deformity (ASD) surgery. There is evidence that the rigidity of posterior spinal constructs may impact risk of PJF. PURPOSE: We hypothesized that lower mean screws per level and decreased rod stiffness would be associated with lower incidence of PJF. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: Patients with ASD and 2-year minimum follow-up were included. Only patients undergoing fusion of >=5 levels, and with LIV at the sacro-pelvis were included. Patients undergoing revision surgery were excluded. In total, 420 patients were analyzed. OUTCOME MEASURES: The primary outcome variable was PJF, defined using previously published radiographic criteria (PJ angle >28degreeand PJ angle >22degree, and >=8mm/>=3mm listhesis at upper thoracic / thoracolumbar levels, respectively).
METHOD(S): The primary independent variables were the mean number of screws per level fused analyzed with a cutoff of 1.8 (determined by ROC analysis) and rod material/diameter. Multivariable logistic regression was utilized to investigate confounding factors, including age, history of osteoporosis, BMI, gender, CCI, preoperative Schwab modifiers, preoperative TPA, postoperative change in lumbar lordosis, upper instrumented vertebra, osteotomy, approach, UIV type (ie, pedicle screw vs other), and number of levels fused.
RESULT(S): Of the total patients, 78.8% were female. PJF occurred in 14.1% of patients. The mean screws per level was 1.7 (SD 0.2), and 57.6% of patients had <1.8 screws per level. PJF occurred in 19.4% vs 9.8% of patients with >=1.8 vs <1.8 screws per level, respectively (p<0.01). In multivariable analysis, patients with <1.8 screws per level exhibited lower odds of PJF (OR 0.39, p<0.01). Rod material and diameter (both p>0.2) were not significantly associated with PJF. Screw density specifically adjacent to the UIV was not related to PJF (p>0.2).
CONCLUSION(S): Among ASD patients undergoing long-segment primary fusion to the pelvis, the risk of PJF was lower among patients with <1.8 screws per level. Rod diameter and material, however, were not significantly associated with PJF. This finding may be related to construct rigidity. It is possible that residual confounding by other patient and surgeon-specific characteristics may exist. Further biomechanical and clinical studies exploring the relationship between screw density and PJK/PJF are warranted. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Hyperlordotic (>20degree) anterior interbody cages (HAI) may be utilized in anterior-posterior fusion (AP-F) in efforts to improve alignment. However, significant increase in segmental lordosis (SL) in HAI without superior articulating process resection (SAP) may result in foraminal stenosis and nerve root compression causing neurological deficits and radiculopathy. Additionally, HAI with SAP may increase SL without concomitant increase in lumbar lordosis (LL). PURPOSE: Assess whether HAI without SAP in APF causes increased neurological complications. STUDY DESIGN/SETTING: Single-center retrospective cohort study PATIENT SAMPLE: A total of 158 patients undergoing single level APF were included, of which 73 had HAI placed and 85 had SAI placed. OUTCOME MEASURES: Outcomes measures included radiographic analysis of pre- and postoperative LL and SL. Perioperative neurological complications were measured including new radiculopathy, iatrogenic motor deficit and malpositioned instrumentation or compressive hematoma causing deficit. Returns to OR within 30 or 90 days were measured including return for foraminal decompression, instrumentation revision, hematoma evacuation, and irrigation and debridement.
METHOD(S): Patients undergoing primary, single level, APF without SAP resection over a 5-year period were included. Patients were classified as HAI or SAI. Outcomes measures included perioperative neurological complications, returns to OR, pre- and postoperative LL and SL. Demographic, procedural and perioperative outcomes were compared using independent samples t-tests and chi-squared analyses as appropriate with significance set at p<0.05. Risk factors for development of neurological complications were assessed with multivariate logistic regression.
RESULT(S): A total of 158 patients (73 HAI, 85 SAI) were included. Age, gender, BMI and CCI were similar between groups. HAI without SAP resulted in significantly larger change in SL (9.84+/-5.84 vs 7.32+/-5.02 deg, p=0.001), without a significantly larger change in LL (8.16+/-1.11 vs 11.5+/-1.69 deg; p=0.641) compared with SAI. HAI without SAP increased overall incidence of neurological deficit (13.69% vs 3.53%; p=0.012), iatrogenic new cases of radiculopathy (10.95% vs 3.53%; p=0.045), and iatrogenic neurological motor deficit (13.69% vs 3.53%; p=0.012). Regression analysis demonstrated that increasing cage lordosis greater than 20degree is an independent risk factor for neurological complications (p=0.046), as is higher preop SL (p=0.022). There were no significant differences in returns to OR.
CONCLUSION(S): We caution HAI implantation without SAP resection due to increased neurological complications from iatrogenic nerve root injury without the benefit of significantly improving LL correction. Use of HAI without SAP resection in single level APF should not be standard practice due to risk of neurological complications. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: The thoracolumbar junction poses increased risk for high stress on upper lumbar discs when not adequately fused. However, controversy persists. This study evaluates outcomes of upper instrumented vertebrae (UIV) selection in the thoracic versus the upper lumbar spine when fusing to the sacrum. PURPOSE: To compare revision rates for thoracolumbar fusions to the sacrum and pelvis at 1- and 2-year follow-up, stratified by UIV selection. STUDY DESIGN/SETTING: Retrospective cohort study at a single institution. PATIENT SAMPLE: A total of 968 patients who had thoracolumbar fusion surgery between 2012-2018 with at least one year of postoperative follow-up. OUTCOME MEASURES: Reoperation rates from 1 and 2 years after revision surgery, reoperation diagnoses, body mass index (BMI), gender, Charleston Comorbidity Index (CCI), perioperative complications, ASA grade (ASA), operative time (OT), and blood loss (EBL).
METHOD(S): A retrospective review of patients undergoing revision spinal fusion with lower instrumented vertebra of S1 or pelvis between 2012-2018 at a single institution was performed. Patients with less than 1 year of follow-up after their index procedure were excluded from the analysis. Patients were categorized based on UIV into 6 groups: T9-T11, L1, L2, L3, L4, and L5. Demographic and operative data were collected and compared between the different UIV groups in each cohort using chi-squared and ANOVA tests. Revision rates at 1- and 2-year follow-up and the reasons for revision were compared between groups.
RESULT(S): There were 168 revision spinal fusions that reached 1-year follow-up, with 54 having UIV at T9-T11, 2 fusions L1 to sacrum, 26 fusions L2 to sacrum, 25 fusions L3 to sacrum, 36 fusions L4 to sacrum, 23 fusions L5 to sacrum. There was significant difference in patient age, with oldest in the L1 group (65.5+/-3.5) and youngest in the L5 group (51+/-15.4 p<0.001). There was significant difference in gender as both cases in L2 was female and L5 fusions only had 39.1% females (p = 0.006). There were no differences in BMI, CCI, and ASA. EBL (1891.6mL+/-1226.9mL p <0.001) and length of stay (7.7+/-3.0 p <0.001) was highest in the T9-11 UIV group. Operative time was highest in the L1 (464.5+/-174.7 p<0.001) UIV group. Levels added on top of prior fusion were calculated by subtracting UIV of index fusion to past UIV. Adding on 2 levels had a 1-year revision rate of 14.3% (p = 0.032), while adding on 1 level had a 0% 1-year revision rate. Adding on 4 levels had a revision rate of 12.5%, and adding on 7 levels had a 50% 1-year revision rate. At 2 years, adding on 1 level had revision rate of 25% and adding on 2 levels had a revision rate of 20% (p = 0.769). There is no statistically significant difference in perioperative complication rates between UIV groups (p = 0.114). The reoperation rate at 1 year for all levels was 9% and highest in UIV at L1 (50%, p=0.06). At 2-year follow-up, the reoperation rate for the total cohort was 32.34% with the highest revision rate for fusion from L2 to sacrum (53.85%) followed by (T9-T11 sacrum fusion 42.31%, L4 to sacrum31.71%, L3 to sacrum 30%, L5 to sacrum 25.04%, L1 to sacrum 25%, p=0.195). Grouping the UIV into lower thoracic (T9-T11), upper lumbar (L2-L3), and lower lumbar (L4-L5) showed similar revision rates at one year (p=0.697). At two years, lower thoracic group had a revision rate of 40% versus, 23.3% in the upper lumbar group (p =0.399).
CONCLUSION(S): There is no statistically significant difference in reoperation rates for revision thoracolumbar fusions to the sacrum/pelvis associated with different UIV selection. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Numerous strategies are used to minimize PJK in (ASD). The use of PPS is one such strategy. Studying this topic is difficult as there is a lack of homogeneity in the patient population being studied. PURPOSE: Investigate if PPS minimizes the risk of perioperative PJK compared to traditional open techniques. 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 are age >18, and one of the following: PT>25, PI-LL>10, or SVA>5 cm. Patients were grouped as MIS (all PPS no open component) or OPEN. Propensity matching was used to create 2 equal groups controlling for: age, BMI, Preop (PI-LL, PI, TPA), and post op (PI-LL correction and posterior levels fused). PJK was evaluated in 2 groups: Mild (PJK10) 10degree change from preop and severe (PJK20) a 20degree change, as previously reported.
RESULT(S): A total of 1,023 patients met criteria: 114 MIS and 909 OPEN. MIS were older with higher BMI. No significant difference was found between groups in preop alignment or SRS Schwab classification. OPEN had more levels fused (11.3 vs 5.5), change in PI-LL (14.9 vs 9.3) and LL (16.2 vs 9.7; all p<0.01). After matching: 77 patients in each group with no difference in demographics or levels fused (6.26 +/- 3.7 OPEN; 6.23 +/- 3.4 MIS). At 1YR NRS leg, ODI, SF-12, EQ5D, SRS-22 were equal. MIS had improved NSR Back compared to OPEN (2.6 vs 3.4; p=0.047). Alignment (PI-LL, TPA, SVA, LL, PT, PI) showed no difference preop, 6 weeks or at 1YR. PJK10 was 23.9% OPEN v 20.3% in MIS at 6 weeks and 28.6% and 19.5% at 1 YR (p>0.59). PJK20 was 2.6% in OPEN vs 3.9% in MIS at 1YR (p=1). The PJK angle was not different (4.3 v 4.2). MIS had less EBL (510 v 1574 cc; p=0.000) longer OR time (448 v 373 min; p=0.022) and more interbodies (3.4 vs 2.1; p=0.000). There was no difference in rate of revision surgery (14.3% OPEN vs 10.4%). Major complications occurred more frequently in OPEN (23.4% vs 9.1%).
CONCLUSION(S): While the use of percutaneous fixation intuitively seems protective for PJK, our study found that when controlling for radiographic deformity, deformity correction, demographics and the magnitude of surgical intervention that percutaneous fixation is equivalent to open techniques in rate of perioperative PJK. 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: 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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STUDY DESIGN/UNASSIGNED:Retrospective clinical review. OBJECTIVE/UNASSIGNED:To assess the use of intraoperative computed tomography (CT) image-guided navigation (IGN) and robotic assistance in posterior lumbar surgery and their relationship with patient radiation exposure and perioperative outcomes. METHODS/UNASSIGNED:Patients ≥18 years old undergoing 1- to 2-level transforaminal lateral interbody fusion in 12-month period were included. Chart review was performed for pre- and intraoperative data on radiation dose and perioperative outcomes. All radiation doses are quantified in milliGrays (mGy). Univariate analysis and multivariate logistic regression analysis were utilized for categorical variables. One-way analysis of variance with post hoc Tukey test was used for continuous variables. RESULTS/UNASSIGNED:= .313, .051, and .644, respectively). CONCLUSION/UNASSIGNED:IGN and robotic assistance in posterior lumbar fusion were associated with higher intraoperative and total-procedure radiation exposure than open cases without IGN/robotics, but significantly less than MIS without IGN/robotics, without differences in perioperative outcomes. Fluoro-MIS procedures reported highest radiation exposure to patient, and of equal concern is that the proportion of total radiation dose also applied to the surgeon and operating room staff in fluoro-MIS group is higher than in IGN/robotics and open groups.

STUDY DESIGN/UNASSIGNED:This was a single-center retrospective review. OBJECTIVES/UNASSIGNED:To explore how age and gender affect PROMIS scores compared with traditional health-related quality of life (HRQL) in spine patients. METHODS/UNASSIGNED:Patients presenting with a primary complaint of back pain (BP) or neck pain (NP) were included. Legacy HRQLs were Oswestry Disability Index (ODI), Neck Disability Index (NDI), and Visual Analogue Scale (VAS). PROMIS Physical Function (PF), Pain Intensity (Int), and Pain Interference (Inf) were also administered to patients in a clinical setting. Patients were grouped by chief complaint, age (18-44, 45-64, 65+ years) and gender. Two parallel analyses were conducted to identify the effects of age and gender on patient-reported outcomes. Age groups were compared after propensity-score matching by VAS-pain and gender. Separately, genders were compared after propensity-score matching by age and VAS-pain. RESULTS/UNASSIGNED:= .022) but not PROMIS-Int or PROMIS-Inf. CONCLUSIONS/UNASSIGNED:Age and gender confound traditional HRQLs as well as PROMIS domains. However, PROMIS offers age and gender-specific scores, which traditional HRQLs lack.

STUDY DESIGN/UNASSIGNED:Single-center retrospective review. OBJECTIVES/UNASSIGNED:The cervicothoracic junction (CTJ) is typically difficult to visualize using traditional radiographs. Whole-body stereoradiography (EOS) allows for imaging of the entire axial skeleton in a weightbearing position without parallax error and with lower radiation doses. In this study we sought to compare the visibility of the vertebra of the CTJ on lateral EOS images to that of conventional cervical lateral radiographs. METHODS/UNASSIGNED:Two fellowship-trained spine surgeons evaluated the images of 50 patients who had both lateral cervical radiographs and EOS images acquired within a 12-month period. The number of visible cortices of the vertebral bodies of C6-T2 were scored 0-4. Patient body mass index and the presence of spondylolisthesis >2 mm at each level was recorded. The incidence of insufficient visibility to detect spondylolisthesis at each level was also calculated for both modalities. RESULTS/UNASSIGNED:On average, there were more visible cortices with EOS versus XR at T1 and T2, whereas visible cortices were equal at C6 and C7. Patient body mass index was inversely correlated with cortical visibility on XR at T2 and on EOS at T1 and T2. There was a significant difference in the incidence of insufficient visibility to detect spondylolisthesis on EOS versus XR at C7-T1 and T1-2, but not at C6-7. CONCLUSIONS/UNASSIGNED:EOS imaging is superior at imaging the vertebra of the CTJ. EOS imaging deserves further consideration as a diagnostic tool in the evaluation of patients with cervical deformity given its ability to produce high-quality images of the CTJ with less radiation exposure.

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.