Faculty Bibliography

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: 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: 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: Frailty has been utilized in cervical deformity (CD) to characterize the influence of preop health state on postop outcomes. Frailty severity may be an important determinant for impaired recovery after CD corrective surgery. No prior studies have examined the associations between increasingly frail states and the trajectory of recovery in CD realignment. PURPOSE: Evaluate postop clinical recovery among CD patients between frailty states undergoing primary procedures STUDY DESIGN/SETTING: Retrospective review of a prospective CD database PATIENT SAMPLE: A total of 106 CD patients. OUTCOME MEASURES: Baseline (BL) to 1-Year(1Y) HRQL Instruments: NDI, mJOA, EQ5D METHODS: Patients>18yrs undergoing surgery for CD (C2-7 Cobb>10degree, coronal Cobb>10degree, cSVA>4cm or TS-CL>10degree, or CBVA>25degree) with HRQL data at BL, 3M and 1Y postop intervals were identified. Patients were stratified by the modified CD frailty index (mCD-FI, Passias et al.) scale from 0-1 (no frailty:<0.3[NF], mild/severe: >0.3[F]). Patients in NF and F groups were propensity score matched (PSM) for TS-CL to control for baseline deformity. Demographics, alignment and Ames-ISSG deformity modifiers were assessed using chi-squared and paired t-tests to compare HRQL outcomes. HRQL outcomes were normalized by dividing BL and postop (3M, 1Y) outcomes by BL for each patient. Normalized scores (y-axis) were plotted against duration of follow-up (x-axis). AUC was calculated for follow-up time intervals; total area for each follow-up interval was divided by cumulative follow-up, determining overall normalized, time-adjusted HRQL outcomes (Integrated Health State [IHS]). IHS was compared between NF and F groups.
RESULT(S): A total of 106 CD patients included (61.7yrs, 66% F, 27.7kg/m2). By frailty group: 52.8% NF, 47.2% F. After PSM for TS-CL (mean: 38.1degree), 38 patients remained in each of the NF and F groups. By surgical approach, 46.1% underwent posterior approach, 19.7% anterior, and 34.2% combined; which was not significant between the frailty groups(p>0.05). At baseline, cervical and spinopelvic radiographic parameters were not significant, except for the C7-S1 SVA (NF: -26.5mm vs F: 15.2mm, p=0.007). According to BL HRQLs, F patients displayed significantly worse NDI scores (NF: 36.8 F: 55.4; p<0.001), mJOA (NF: 14.7, F: 12.7; p=0.002), and EQ5D (NF: 0.78, F: 0.69; p<0.001). All frailty groups exhibited BL to 1Y improvement in NDI, EQ5D and NRS Neck Pain (all p<0.001). After HRQL normalization, F patients had more improvement in mJOA scores at 3M (p=0.065) as well as NDI (p=0.096) and EQ5D (p=0.016). IHS-adjusted HRQL outcomes from BL to 1Y showed a significant difference in EQ5D scores (NF: 1.02, F: 1.07, P=0.016). No significant differences were found in the IHS NDI and mJOA between frailty groups (p>0.05). F patients had more postop major complications (31.3%) compared to the NF (8.9%), p=0.004, though DJK occurrence and reoperation between the groups was not significant.
CONCLUSION(S): While all groups exhibited improved postop disability/pain scores, frail patients recovered better in overall health state. Despite frail patients having more complications, they seem to have overall better patient-reported outcomes, signifying that with frailty severity, patients have more room for improvement postop compared to baseline quality of life. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: With the rise of health care costs and a focus on value-based outcomes, hospitals have become more cognizant on cost of revisions and complications. However, literature on the effect of distal junctional kyphosis in driving up health care costs is scarce. PURPOSE: To evaluate the effect of distal junctional kyphosis on the cost effectiveness of corrective cervical deformity surgery. STUDY DESIGN/SETTING: Retrospective review of a single surgeon database. PATIENT SAMPLE: This study included 123 cervical deformity patients. OUTCOME MEASURES: Cost per QALY.
METHOD(S): Cervical deformity patients with minimum 1-year HRQL follow-up were included. Means comparison tests assessed differences in baseline demographic and clinical data. Utility data was calculated using published conversion methods to convert NDI to SF-6D. QALYs utilized a 3% discount rate to account for residual decline to life expectancy (78.7 years). Costs was calculated using the PearlDiver database incorporating complications, comorbidities (CC), major complications, and comorbidities (MCC) were assessed according to CMS.gov manual definitions. Reimbursement consisted of a standardized estimate using regression analysis of Medicare pay-scales for all services rendered within a 30-day window, including estimates regarding costs of postoperative complications, outpatient health care encounters, revisions and medical-related readmissions. After accounting for CC, MCC, length of stay (LOS) and death, cost per QALY at 2Y was calculated for revisions due to distal junctional kyphosis.
RESULT(S): A total of 123 cervical deformity patients met inclusion criteria (57.22yrs, 54%F, 29.0kg/m2). At baseline, patients presented radiographically as: PT (16.9+/-9.7), PI (54.7+/-11.4), PI-LL (-2.9+/-12.6), SVA (80.5+/-49.8), cSVA (28.4+/-20.6), TS-CL (26.6+/-14.4). Surgical details: EBL of 708 mL, operative time of 438.6 min, with 29.51% undergoing an anterior approach, 50.82% posterior-only approach, and 19.67% combined approach. Overall, 7.9% of patients developed DJK within two years postoperatively. Average cost of revision surgery due to DJK within 2years of index surgery was $50,736 +/- 31,467. Patients that developed DJK within 2years of index surgery trended toward having a greater baseline NDI (62.8 vs 55.47, p>0.05) and showed less improvement in NDI at 2 years (4 vs 16.6). Overall, cost per QALY was higher for patients developing DJK at 2 years ($28,483 vs $20,989).
CONCLUSION(S): Cervical deformity revisions due to distal junctional kyphosis had a cost per QALY of $28,483. Efforts to limit postoperative DJK after surgical intervention can further limit additional costs associated with revisions and complications. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Frailty is a baseline measure of disability that transcends age alone and has been determined a strong predictor of outcomes following adult spinal deformity (ASD) surgery. This postop impact calls for investigation of unique adjustment of Global Alignment and Proportion (GAP) scores accounting for frailty. This adjustment in spinal proportion may help surgical planning for individualized, optimal postop outcomes. PURPOSE: Modify the GAP score with frailty to optimize outcomes in surgical ASD patients. STUDY DESIGN/SETTING: Retrospective review of a single-surgeon comprehensive ASD database PATIENT SAMPLE: A total of 140 ASD patients OUTCOME MEASURES: Frailty-adjusted GAP scores; Health Related Quality of Life scores (HRQLs): ODI, SRS-22 METHODS: Surgical ASD patients (SVA>=5cm, PT>=25degree, or TK >=60degree, >3 levels fused) >=18 years old with available baseline (BL) radiographic data were isolated in the single-center Comprehensive Spine Quality Database (Quality). Patients were dichotomized by the ASD frailty index, F (Not Frail, Frail). Linear regression analysis established radiographic equations for frailty-adjusted GAP Scores at baseline and 2-years involving relative pelvic version, relative lumbar lordosis, lordosis distribution index, relative spinopelvic alignment, and an age factor to formulate a sagittal plane score. Patients were restratified into frailty-adjusted proportionality groups: Proportional (<5.8), Moderately Disproportional (MD) (5.8-7), Severely Disproportional (SD) (>7). Frailty-adjusted GAP proportionality at 2-years were compared to adjusted-BL to determine whether patients improved, deteriorated or remained the same in their spine proportion.
RESULT(S): A total of 140 patients were included (55.5+/-16.4 yrs, 77.5% female, 25.2+/-4.7 kg/m2). BL frailty: 32.8% not frail, 67.2% frail. Primary analyses demonstrated correlation between BL frailty score and BL and 2-year GAP scores(P<0.001). Linear regression analysis(p<0.001) developed a frailty-adjusted GAP threshold equation: 4.4 + 0.93*(frailty score). Adjusted-baseline scores were taken and re-stratified based distribution and placed 26.4% of patients in Proportional, 26.6% MD, and 44% SD. BL adjusted GAP scores by frailty group: 5.3 Not Frail, 7.5 Frail; p<0.001. At 2-years, GAP scores were grouped into the frailty-adjusted proportionality groups: 66.2% Proportional, 10.8% MD, and 23.1% SD. Patients who were 2-year MD/SD underwent significantly more reoperations (>33.5%) compared to Proportional (12.8%), p=0.015. SD 2-year patients developed increased PJK at the 1-year mark (40%, Proportional: 13.9%, MD:7.1%, p=0.003), as well as had worse 2-year ODI and SRS-22 satisfaction scores(p<0.050). 47.5% improved in GAP (63.4% of frail patients), 12.3% deteriorated, and 40.2% remained in the same proportionality group at 2-year follow up.
CONCLUSION(S): Significant associations exist between frailty and spinal proportion. By adjusting the GAP proportionality groups accounting for baseline frailty contributed to improved outcomes and minimized reoperations. The adjusted GAP groups appeal for less rigorous spine proportion goals in severely frail patients. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: This study evaluates the necessity of a multi-rod construct to help prevent a pseudarthrosis in ASD surgery of lesser magnitude. Regardless of an interbody at L5/S1, a multi-rod construct does not decrease the risk of developing a pseudarthrosis. If a pseudarthrosis develops in patients who undergo an interbody fusion at L5/S1, it is more likely to occur above the L5/S1 level and the number of rods used does not decrease this risk. PURPOSE: To examine the necessity of IBF and multi-rod use to prevent pseudarthrosis in these lesser magnitude ASD surgeries. STUDY DESIGN/SETTING: Retrospective review of a multicenter database. PATIENT SAMPLE: A total of 483 patients met our inclusion criteria of pelvic fixation, > 2 year follow up, >5 levels fused, no 3-column osteotomy (3CO), and no multi-level interbody fusions. OUTCOME MEASURES: Pseudarthrosis rate and location in ASD patients.
METHOD(S): A multi-center database was evaluated to identify patients with pelvic fixation, > 2 year follow up, >5 levels fused, and no 3-column osteotomy (3CO). We define a lesser magnitude ASD surgery as surgeries that do not include 3CO or multi-level interbody fusions. In this cohort, ASD patients with and without an IBF at L5/S1 were assessed to evaluate if the number of rods had an impact on the pseudarthrosis rate. Pseudarthrosis was determined by intraoperative findings or record review. Fisher's exact tests, univariate and multivariate analysis were used to identify predictors of pseudo.
RESULT(S): A total of 483 patients met our inclusion criteria with an average follow-up of 48 months. Of those, 321 (66%) had interbody at L5/S1 (IBF). Twenty-three percent of IBF patients had a MR construct and 77% had a SR construct. In the non-IBF group, 33% had a MR construct. In the IBF group, the MR construct did not impact the pseudarthrosis rate compared to a SR construct, (6.8% vs 5.2% respectively, p=.35). In the IBF group, 29% (4) of MR patients and 75% (6) of SR patients with pseudo received BMP. However, regardless of the rod construct, ASD patients with an interbody at L5/S1 had an increased risk of having a pseudarthrosis above this level (OR.096, p=.045). Also, the MR construct did not decrease the risk of developing a pseudarthrosis in the non-IBF group (0% vs 4.5%, p=.18).
CONCLUSION(S): In ASD surgery of lesser magnitude, a multi-rod construct does not decrease the risk of developing a pseudarthrosis. Patients who have an interbody fusion at L5/S1 are more likely to develop a pseudarthrosis above this level, regardless of the rod construct. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: As the field of corrective cervical deformity (CD) surgery progresses, surgeons continue to take on more challenging cases. In order to minimize suboptimal postoperative outcomes it is important to develop a tool that allows for proper preoperative risk stratification. PURPOSE: Develop individualized predictive models for identification of risk-factors that lead to the development of major complications, revisions, and unplanned reoperation. STUDY DESIGN/SETTING: Retrospective cohort study of a prospective adult cervical deformity database. PATIENT SAMPLE: A total of 105 CD patients. OUTCOME MEASURES: Major complications (prolonged hospitalization, invasive intervention, prolonged or permanent morbidity, death within 1 year[1Y]), unplanned revision or reoperation after CD surgery within 1Y, HRQOL (NDI, mJOA, EQ5D).
METHOD(S): CD patients (cervical kyphosis >10degree, coronal scoliosis >10degree, cSVA >4cm, TS-CL >10degree, or CBVA >25degree) >=18 years old with complete baseline (BL), 1Y HRQoL and radiographic data. Patients were stratified into two groups based on their outcome from surgery: revision (Rev) and major complication (MC). Descriptive analysis identified cohort demographics, radiographic parameters and surgical details. Univariate analysis of preoperative and surgical factors was conducted to determine associations with any of the two outcomes. Stepwise logistic regressions identified surgical, radiographic, and HRQL factors that were associated with Rev or MC. Decision tree analysis established cut-offs for predictive variables.
RESULT(S): A total of 105 CD patients were included (61.6yrs, 67%F, BMI: 28.4kg/m2, CCI: 0.96+/-1.3). Surgical details: 7.6+/- 3.7 levels fused; mean EBL of 816 mL. By surgical approach, 45.71% had a posterior approach, 35.24% combined approach, and 19.05% anterior approach. Radiographically at baseline, patients presented with: PT: 18.9+/- 11.3; PI: 53.0+/-11.2; PI-LL: -0.45+/-17.2; SVA: -4.3+/-66.8, TS-CL: 37.9 +/-20.2; cSVA: 38.4+/-19.9. Postoperatively, 20 patients experienced a MC and 17 patients underwent a subsequent rev. instrumentation location (LIV: 1.1[1.0-1.3] and UIV: 1.5[1.1-2.1]) was significantly associated with undergoing a rev after index surgery (all p<0.05). The development of a postoperative MC was significantly associated with BL radiographic pelvic parameters (all <0.05). Predictive modeling incorporating preoperative and surgical factors identified development of a Rev to include: UIV>C3, LIV>T3, C2-T3 SVA<46.7degree, C2-C7 SVA>57.6degree, CTPA>7.8degree, and C2S<60.4 (AUC:0.80). For developing a MC, a model consisting of preoperative and surgical factors included BL EQ5D-VAS<30, TS-CL>59.2degree, C2-C7 SVA > 69.1degree, C2-T3 SVA < 18.6, Apex C2-C7 SVA >4.25, surgical invasiveness and posterior osteotomies (AUC:0.83).
CONCLUSION(S): Major adverse events were not uncommon following adult cervical deformity correction. Risk stratification models were developed to predict with high accuracy the occurrence of these common significant postoperative events. Revisions were predicted with an accuracy of 80% using a predominance of radiographic variables, while the occurrence of other major complications was also predicted with high reliability utilizing additional baseline HRQoL data and surgical factors. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Due to inherent patient and surgical factors, some adult spinal deformity patients are at higher risk of larger blood loss. This is associated with increased risk of complications, coagulopathy, and higher requirements for blood component replacement intraoperatively. The medical team should be aware of expected blood loss in order to adequately plan patient monitoring and blood product requirements. PURPOSE: This study aims to develop and validate a model based on patient characteristics and surgical strategies to predict which patients undergoing adult spinal deformity surgery are at greater risk of massive intra-operative blood loss. STUDY DESIGN/SETTING: Retrospective analysis of a multicenter prospective database. PATIENT SAMPLE: Surgical ASD patients undergoing long fusions (>5 levels). OUTCOME MEASURES: Massive intraoperative blood loss (>7% of a patient's ideal body weight), ICU stay, complications.
METHOD(S): Surgical adult spinal deformity patients undergoing long fusions (> 5 levels) were analyzed. Massive blood loss was defined as an intraoperative blood loss over 7% of a patients' ideal body weight, in accordance to the anesthesia literature. The impact of mEBL on complications and ICU stay was assessed through multivariate poisson and logistic regression, adjusting for baseline patient demographics and magnitude of surgery. Multivariate logistic regression modeling was used to build a prediction model of mEBL. Potential predictors were identified using univariate analysis. The model was built using a combination of backward elimination and bootstrap selection. Model fit was assessed using the Hosmer-Lemeshow test and the ROC curve. Split sample internal cross-validation was performed.
RESULT(S): A total of 1,205 patients met inclusion criteria, and mEBL occurred in 7.8% (94/1205) of cases. In this cohort, mEBL was an independent risk factor for major complications (IRR 2.89, p=0.0001), and postoperative ICU stay (OR 4.68, p=0.001). Predictors of mEBL included: revision surgery (OR 1.66, p=0.05), performing a three-column osteotomy (OR 2.65, p=0.0001), number of levels fused (OR 1.19, p=0.0001), number of levels decompressed (OR 1.15, p=0.004), and number of LLIF interbodies (OR 0.69, p=0.066). The predictive model had a good discrimination (ROC curve 0.76), and good calibration (Hosmer-Lemeshow p=0.39), which held true when performing split-sample cross-validation.
CONCLUSION(S): We built and validated a model to predict massive intra operative blood loss in ASD surgery. In this model, baseline patient demographics and elements of the surgical strategy are used to predict which patients are at greater risk for massive blood loss. This tool would be of particular help to the anesthesia team, allowing to identify preoperatively which patients are at greater risk and plan intraoperative care and fluid management accordingly. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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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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