Faculty Bibliography

BACKGROUND CONTEXT: Patients with less severe adult spinal deformity undergo surgical correction and often achieve good clinical outcomes. However, it is not well understood how much clinical improvement is due to sagittal correction. PURPOSE: Derive baseline thresholds in radiographic parameters that, when exceeded, result in dramatic clinical improvement from surgical correction. STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: A total of 689 ASD patients. OUTCOME MEASURES: Radiographic alignment, clinical outcomes (ODI SCB).
METHOD(S): ASD patients with BL and 2-year (2Y) data included. Parameters assessed: SVA, PI-LL, PT, T1PA, L4-S1 Lordosis, C2-C7 SVA (cSVA), C2-T3 and C2 Slope (C2S).
Outcome(s): Good Outcome (GO): [Meeting either: 1) SCB for ODI by 2Y (change greater than 18.8), or 2) ODI 4.5 by 2Y. Binary logistic regression assessed each parameter to determine if correction was more likely needed to achieve GO. Conditional inference tree (CIT) run machine learning analysis generated baseline thresholds for each parameter, above which, correction was necessary to achieve GO.
RESULT(S): Included: 447 ASD patients. There were 223 (50%) patients achieving GO by 2 years. Binary logistic regression analysis demonstrated correction of all 5 thoracolumbar parameters (SVA, T1PA, PI-LL, PT, L4-S1) were more often needed to achieve GO (all p.001). Of patients with baseline T1PA above 20degree, 95% required correction to meet Good Outcome (95% vs 54%, p.001). CIT-generated thresholds were significant for each parameter, with a baseline C2 slope above 15degree necessitating correction more often to obtain clinical success (OR: 8.1, [4.1-16.2]; p.001).
CONCLUSION(S): Our study highlights there is a tipping-point beyond which sagittal correction has an exponential influence on clinical improvement, reflecting the line where deformity becomes a significant contributor to disability. These new thresholds delineate patients suitable for sagittal correction, as opposed to conventional treatment of degenerative disc processes. Adherence to these benchmarks may improve the utility gained from surgical intervention for degenerative conditions and deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Tranexamic acid (TXA) is commonly used to lower blood loss in ASD surgery. Despite widespread use of TXA in ASD surgery, there is a lack of consensus regarding the optimal dosing intraoperatively. PURPOSE: This study aims to assess differences in blood loss and complications between high-dose, medium-dose, and low-dose TXA regimens. Complex ASD patients who receive high-dose TXA will have decreased blood loss compared to those who receive low-dose TXA. STUDY DESIGN/SETTING: Retrospective Review. PATIENT SAMPLE: A total of 265 ASD patients in a multi-center prospective study were retrospectively analyzed. OUTCOME MEASURES: Blood loss (ml), Major Blood Loss (>90th percentile ml), units transfused intraoperatively, units transfused perioperatively.
METHOD(S): Patients were separated into three cohorts by TXA regimen: 1) low-dose patients had =20mg/kg loading dose with =2mg/kg/hr maintenance dose 2) medium-dose patients had 20-50 mg/kg loading dose with 2-5 mg/kg/hr maintenance dose. 3) high-dose patients had =50mg/kg loading dose with =5mg/kg/hr maintenance dose. Major or minor blood loss was defined as above or below the 90th percentile of our cohort respectively. Multivariable analysis controlled for levels fused, BMI, platelets, Hgb, OR time, 3CO, and radiographic alignment.
RESULT(S): Fifty-four (20%) patients received low-dose regimen, 133 (50%) received medium-dose and 80 (30%) received high dose. Mean blood loss was 1,551+/-1,295 ml, intraoperative units RBCs 1.52+/-2, and perioperative units RBCs 2.3+/-2.3. Mean major blood loss was 4,566+/-1,516ml and minor blood loss 1,236+/-755ml. Compared to the low-dose group, patients in the high-dose group had 77.8% decreased odds of major blood loss (OR 0.222; P=0.007), decreased blood loss (Coef. -540.92ml; P=0.019), units transfused intraoperatively (Coef. -.739 units; P < 0.001), and units transfused perioperatively (Coef. -0.328 units; P=0.025). Compared to medium-dose group, the high-dose group had less units transfused intraoperatively (Coef. -.59 units; P < 0.001) and perioperatively (Coef. -.42 units; P < 0.001) with no difference in blood loss. There was no difference between the medium and low dose groups in blood loss or units transfused. There was no association between high-dose TXA regimen and increased rates of DVT, PE, or any medical complication before six weeks. No patients had a seizure.
CONCLUSION(S): In this multicenter prospectively collected database, ASD patients receiving high-dose intraoperative TXA have decreased odds of major blood loss, less RBC transfusions intraoperatively and 540ml less blood loss compared to low dose TXA, without additional risk of seizure or thromboembolic complications. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adolescent idiopathic scoliosis (AIS) affects up to 4% of adolescents. As of yet, the characterization of traumatic injuries in AIS patients is unknown. PURPOSE: To compare the risk of varying fracture locations after blunt trauma between patients with and without AIS. STUDY DESIGN/SETTING: Retrospective review. PATIENT SAMPLE: The Kid's Inpatient Database (KID) was queried from 2003 to 2009 to identify all patients aged 0-20 with AIS admitted for acute trauma. OUTCOME MEASURES: The rates of various spinal fracture patterns as well as risk factors for vertebral fracture.
METHOD(S): KID was queried for AIS patients aged 0-20 years, from 2003 through 2009. AIS patients admitted for acute trauma were isolated. Mechanisms of injury (MOI), fracture locations and surgical procedures were assessed. Trauma AIS patients were then propensity-score matched to a general (Gen) trauma population of 323,729 KID patients, using age, sex and MOI. Fracture types were compared utilizing Chi-square and t-tests. Logistic regression analysis predicted relative odds of fracture in AIS patients.
RESULT(S): Of 41,142 AIS cases identified, 442 patients suffered acute blunt trauma (2003: 112; 2006: 139; 2009: 186). Of those, the most prevalent MOIs were MVA (37.1%), pedestrian struck (PS) (22.9%), falls (18.3%) and assault (7.6%). Of the 442 acute blunt trauma patients, 99 (22.3%) sustained vertebral fracture. Of those, 25 patients had cervical fractures (MVA 66.52%, PS 24.14%, fall 6.9%), 23 thoracic (MVA 47.8%, PS 21.7%, fall 26.1%), 35 lumbar (MVA 57.1%, PS 20%, fall 25.7%), and 16 sacral/coccygeal (MVA 68.8%, PS 25%, fall 12.5%). Twenty-eight patients underwent spinal fusion (2-3 levels: 35.7%, 4-8 levels: 25.0%, >9 levels: 14.0%) and 14 had vertebral fracture repairs. After propensity-score matching (AIS: 432, Gen: 432), AIS patients had significantly more vertebral fractures (99 vs 52, p<0.001) and exhibited higher rates of thoracic (5.3% vs 2.5%, p=0.035) and lumbar fractures (8.1% vs 2.8%, p<0.001). Logistic regression showed AIS patients had increased odds of overall fracture (OR: 2.1 95% CI [1.4 - 3.1], p<.001), thoracic (OR: 2.2 95% CI [1.0 - 4.5], p=0.039) and lumbar fractures (OR: 3.1 95% CI [1.6 - 6.1], p<0.001).
CONCLUSION(S): AIS trauma patients relative to a normative trauma population were more likely to present with a vertebral fracture; specifically, thoracic and lumbar fractures. Authors acknowledge the limitations of the KID database, such as unavailability of radiographic data. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Several studies have suggested that Hounsfield units (HU) in the spine are associated with increased complications for adult spinal deformity (ASD) patients. PURPOSE: The aim of this study is to assess whether there exists a threshold for HU that is associated with increased blood loss following ASD surgery. We hypothesize that HU below thresholds on spinal CT are predictive of increased blood loss during surgery and implant complications within 90 days after surgery for ASD. STUDY DESIGN/SETTING: Retrospective analysis. PATIENT SAMPLE: ASD patients who had HU measured in the spine were identified from a multicenter database. OUTCOME MEASURES: High Intraoperative blood loss and implant complications within 90 days of surgery.
METHOD(S): HU at L1, upper instrumented vertebrae (UIV) and total averages were assessed. Threshold linear regression with Bayesian information criteria was utilized to identify optimal cut-offs for predicting high blood loss (>2100mL, top 25% by volume) or any implant complications within 90 days. Implant complications included loosening, breakage and dislocation of rods or screws. Multivariable logistic regression was utilized controlling for age, gender, comorbidity, osteotomy and levels fused.
RESULT(S): Of 527 patients included, the mean age was 61+/-14. Mean L1 HU was 154.59+/-87, UIV HU was 175.1+/-304, and total average HU was 165+/-168. There were 59 patients with high blood loss (mean 5,026+/-233ml) and 467 with low blood loss (1,331+/-39.5ml). Threshold regression analysis identified that a cut-off of =140.33 was optimal for predicting high blood loss and =99.75 total average HU was optimal for predicting implant complications within 90 days of surgery. On multivariable analysis, L1 HU less than 140 was associated with 1.57x higher odds of high blood loss (P=0.032). Total average HU less than 100 was associated with a 3.6x higher odds of having an implant related failure within 90 days of surgery (P=0.035).
CONCLUSION(S): In this prospective multi-center study, Those with L1 HU=140 had a 1.52x higher odds of high blood loss. Patients with an average HUof =100 have 3.6x higher odds of implant related complication within 90 days of surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adult cervical deformity (ACD) can have profound impact on health-related quality of life (HRQL). Operative treatment for ACD is associated with high complication rates due to the complexity of surgery and the frailty of the patients affected. Very few studies have focused on outcomes of operative ACD treatment. PURPOSE: To assess whether operative treatment for ACD significantly improves HRQL at minimum 2-yr followup. STUDY DESIGN/SETTING: Multicenter, prospective cohort study. PATIENT SAMPLE: Operatively treated ACD patients. OUTCOME MEASURES: Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA), EuroQol-5D (EQ-5D), and numeric rating scale (NRS) for neck and back pain.
METHOD(S): Operatively treated ACD patients were assessed at baseline, standardized follow-up intervals and through direct mailings. Patient-reported outcomes measures (PROMs) included: NDI, mJOA, EQ-5D and NRS for neck and back pain. Complications were classified as perioperative (=30 days) or delayed (>30 days). Analyses focused on patients with minimum 2-yr followup.
RESULT(S): Of 169 ACD patients, the 102 (60%) with minimum 2-yr followup (mean=3.4 yrs, SD=1.9 yrs, range=2 to 8.1 yrs) had a mean age of 62 yrs (SD=11) and 64% were women. Surgical approaches included anterior-only (22.8%), posterior-only (39.6%) and combined (37.6%). The mean numbers of vertebrae fused anteriorly and posteriorly were 4.3 (SD=1.1) and 9.4 (SD=3.4), respectively, with 16% having a 3-column osteotomy. PROMs significantly improved from baseline to last follow-up, including NDI (47.3 to 33.0), mJOA (12.0 to 12.8; for patients with baseline score 0.05). Overall, 58 (56.9%) patients had at least 1 complication, 41 (40.2%) had at least 1 perioperative complication, and 35 (34.3%) had at least 1 delayed complication. The most common complications included dysphagia (18.6%), distal junctional kyphosis (6.9%), instrumentation failure (6.9%), cardiac events (6.9%), dysphonia (4.9%), nerve sensory deficit (3.9%) and respiratory failure (3.9%). For patients with at least 2-yr follow-up, 12 patients underwent a total of 15 reoperations (9 had 1 and 3 had 2). Notably, the 67 patients who did not achieve 2-yr follow-up were similar to study patients based on demographics, comorbidities and baseline PROMs. Reflective of the frailty of this patient population, there were 18 deaths among the 67 patients without minimum 2-yr followup. These deaths occurred between 0.2 and 34.8 months following surgery. Although most occurred at least 6 months after surgery and likely were not directly related to surgery, 4 occurred within 4 months of surgery, including 1 due OSA/narcotics, 1 due to pneumonia, and 2 with unknown causes.
CONCLUSION(S): This multicenter, prospective analysis demonstrates that operative treatment for ACD provides significant improvement of HRQL at minimum 2-yr (mean 3.4-yr) followup. These findings may prove useful for patient counseling in the context of the substantial impact of ACD. Further studies will be needed to assess the long-term durability and cost-effectiveness of surgical treatment for ACD. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: The ACS-NSQIP and SpineSage are both easy to use and readily available online perioperative risk calculators The ACS-NSQIP calculator predicts perioperative complications after surgery, but lacks more spine-specific predictors. The SpineSage platform was developed as a tool built for predicting complications in spine surgery. While a limited number of studies have shown it be predictive of both overall and major medical complications in spine surgery, large external validation studies are limited and none have directly compared NSQIP against SpineSage in the same cohort of spine surgery patients. PURPOSE: Assess the ACS-NSQIP Risk Calculator and SpineSage informatics platform for prediction of perioperative complications in spine surgery STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: A total of 440 patients undergoing thoracolumbar spine with or without fusion. OUTCOME MEASURES: Any complication, serious complication, pneumonia, cardiac, dural tear, SSI, UTI, VTE, reoperation, death and LOS METHODS: Each patient was entered into the ACS-NSQIP and SpineSage calculators and predicted risk for specific complications were directly compared to actual risks. Paired t-tests compared the differences between calculators and their predictability of complications. Patients were ranked based on risk predicted for each complication and the highest tertile for each was isolated. Multivariate regression controlling for age and gender was used to determine if the highest tertile for each risk calculator had predictability in complications following spine surgery.
RESULT(S): Mean LOS 4.2+3 days, EBL 444+300 mL, operative time 256+240 min, and levels instrumented 2.1+2.3. When assessing the four complications predicted by SpineSage there were significant differences in three of the four variables, as SpineSage underpredicted the risk of all and serious-complications (p.5). Both calculator tertiles were trending towards significance for major medical complications (SpineSage: OR: 2.0, [0.94-4.23], p=.073; ACS-NSQIP: OR: 1.8,[0.96-3.48],p=.067). When examining any medical risk, only ACS NSQIP had significant predictability for any medical complication (OR: 2.1, [1.3-3.3]; p=.003).
CONCLUSION(S): Similar to previous studies, the ACS-NSQIP score underpredicted most complications, with the exception of LOS and death. In contrast to previous studies, our data suggest SpineSage was not predictive of actual rates of complications. As both calculators are highly accessible and provide at least some objective perioperative risk data points, we recommend them as a guiding tool but not as an absolute endpoint for clinical decision making as they may be inaccurate and insensitive. Further, higher powered studies elucidating the findings in this study should be conducted. Additionally, the assessment of these calculators for a specific subset of patients, such as deformity, degenerative or pediatrics, can further help guide clinicians regarding the utility of these calculators for their particular patient populations. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Evidence on long-term surgical recovery in adult spinal deformity (ASD) patients who are both frail and have an invasive procedure is limited. PURPOSE: This study aims to evaluate frail and invasive patients with 5-year recovery kinetics. We hypothesize that patients who are both frail and have invasive surgeries will have adverse postoperative recovery kinetics STUDY DESIGN/SETTING: Retrospective review. PATIENT SAMPLE: A total of 133 ASD patients with complete HRQOL data at preoperative, 1-year, 2-year, 5-year follow-up were included. OUTCOME MEASURES: Integrated Health State Scores (IHS) in Oswestry Disability Index (ODI), Short-form 36 (SF-36) physical (PCS) and mental (MCS) component score, and Scoliosis Research Society (SRS)-22r measures METHODS: ASD-FI scores were used to stratify non-frail (0.3) patients. ASD-SR scores were used to stratify low invasive (90) surgeries. Using ASD-FI and ASD-SR, patients were separated into four cohorts: non-frail low invasive (NFLI), frail low invasive (FLI), non-frail high invasive (NFHI), and frail high invasive (FHI). HRQOLs at 1 year, 2 years, and 5 years were normalized against preoperative values. AUC was calculated across time points to generate an integrated health state score (IHS). Multivariable linear regression was used to compare IHS scores of FLI, NFHI, and FHI to NFLI while controlling for age, gender, comorbidity, and radiographic alignment.
RESULT(S): Of 633 eligible ASD patients, 339 had 5-year follow-up. Of those, 125 patients with complete HRQOL data at preoperative, 1-year, 2-year, and 5-year visits were included; 27.2% (34) were NFLI, 20.0% (25) were FLI, 26.4% (33) were NFHI, and 26.4% (33) were FHI. Using NFLI as the referent, FLI and NFHI did not have differences in ODI, MCS, PCS or SRS-22r IHS scores (P >0.05). On multivariable analysis of integrated health scores, FHI had higher MCS (7.6 vs 5.47; P=0.0188), SRS activity (6.97 vs 5.67; P=0.0004), SRS pain (8.49 vs 6.4; P=0.001), SRS appearance (8.97 vs 6.81; P=0.0014), SRS satisfaction (11.71 vs 7.97; P=0.0033), and SRS total (7.49 vs. 6.09; P=0.0002), indicating more improved recovery over a 5-year period. Patients who were FHI had higher rates of complications (P <0.05).
CONCLUSION(S): Despite having more complications, patients who were frail and underwent more invasive surgeries were more likely to have greater overall improvement in activity, pain, and satisfaction over a 5-year period relative to preoperative baseline. Our results suggest that frailty in combination with invasiveness do not hinder long-term postoperative recovery kinetics, in comparison to frailty or invasiveness alone. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Identifying the components needed for an optimal adult spinal deformity (ASD) surgical outcome could help inform surgeons and improve ASD treatment. However, defining the components that create an optimal outcome for ASD surgery is challenging because outcome metrics depend on multiple perspectives. A patient may receive a technically successful complication-free surgery but may report dissatisfaction with the treatment outcome. Conversely, a patient may incur multiple postoperative complications with high societal cost but report satisfaction with the surgical outcome. PURPOSE: (1) Define an "optimal" ASD surgical outcome by integrating outcome metrics from multiple perspectives, and (2) identify the patient-specific and surgical components of ASD treatment that surgeons can employ to improve ASD surgery by creating a model that predicts a multi-perspective "optimal" surgical outcome. STUDY DESIGN/SETTING: Prospective, multicenter analysis. PATIENT SAMPLE: ASD patients enrolled into a prospective multicenter study. OUTCOME MEASURES: Scoliosis Research Society-22r questionnaire (SRS-22r), Oswestry Disability Index (ODI), postoperative complications.
METHOD(S): Surgically treated ASD patients prospectively enrolled into a multicenter study from 2009-2018 were assessed at minimum 2-year follow-up for optimal outcome defined as (1) no major postoperative complication or complication requiring surgery, (2) patient reached MCID for ODI and SRS-22r subscore, and (3) patient satisfied and indicates would have the surgery again. Demographic, radiographic, PROM and surgical variables were assessed for associations with optimal outcome. Multivariate regression models were built based on level of upper instrumented vertebra (UIV) to identify variables that created a best fit predictive model for optimal outcome by R2 maximization and AIC/BIC minimization.
RESULT(S): Of 1291 patients, 788 (mean 3.5 years follow-up), were eligible for study and evaluated. Optimal outcome patients (OP; n=196) had less preoperative opioid use (47.5% vs 56.8%) and fewer histories of prior spine surgery (65.4% vs 77.3%) than nonoptimal outcome (NO; n=592), respectively (p 0.05). Creation of the best fit predictive model for optimal outcome demonstrated synergy between several modifiable variables including preoperative BMI and opioid and tobacco use, final SVA and scoliosis, and use of supplemental rods and PJF prophylaxis. Refining the model for specific surgeries based upon UIV demonstrated increased synergistic impact of the modifiable variables and predictive accuracy (thoracolumbar UIV R2 =0.41; upper thoracic UIV R2 =0.77).
CONCLUSION(S): No single surgical or radiographic variable is independently predictive of an a priori defined multiperspective optimal outcome following ASD surgery. However, predictive modeling identified preoperative BMI, opioid and tobacco use, final SVA and scoliosis, and use of supplemental rods and PJF prophylaxis as variables surgeons can optimize and/or employ that act synergistically to predict an optimal ASD surgical outcome. Future research will focus on development of predictive models that highlight the synergistic effects of patient specific and interventional variables to improve surgical outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Prior reports have focused on grading fusion status after adult spinal deformity (ASD) surgery; however, few focused on fusion status after 4-years postop. PURPOSE: To identify risk factors for nonunion in a prospective cohort of ASD patients with long-term follow-up (=4 years). STUDY DESIGN/SETTING: Prospective multicenter observational series. PATIENT SAMPLE: Database enrollment required age =18 years, scoliosis =20degree, sagittal vertical axis (SVA) =5cm, pelvic tilt =25degree, or thoracic kyphosis =60degree. OUTCOME MEASURES: Fusions were rated as bilaterally fused (A), unilaterally fused (B), partially fused (C), or not fused (D). Primary outcome was fusion (grade A or B) vs nonunion (grade C or D) at minimum 4-year follow-up. Secondary outcome measures included health-related quality of life (HRQL) (Oswestry Disability Index [ODI], Short Form-36 [SF-36] scores, Scoliosis Research Society-22 [SRS-22r] scores).
METHOD(S): Surgically treated ASD patients prospectively enrolled into a multicenter study (2008-2020) were assessed for fusion (grade A or B) vs nonunion (grade C or D). Inclusion required postop fusion grading at minimum 4-year follow-up. Demographics, frailty, comorbidities, alignment (baseline and initial correction), index surgery (total levels fused, iliac fixation, interbody fusion [IBF], use of bone morphogenetic protein [BMP] and/or demineralized bone matrix [

BACKGROUND CONTEXT: Loss of lumbar curvature is often expressed as an angular regional loss. Previous work comparing adult spinal deformity (ASD) lumbar alignment to their age-and-PI adjusted normative value demonstrated that, contrary to general belief, a large proportion of the curvature is lost proximally (L1-L4). This study is a follow-up looking not only at regional angles, but also at the spinal contour collectively. PURPOSE: Investigate the difference of lumbar shape between ASD and age-and-PI adjusted normative values. STUDY DESIGN/SETTING: Retrospective review of an ASD registry. PATIENT SAMPLE: A total of 119 asymptomatic volunteers and 362 ASD patients. OUTCOME MEASURES: Sagittal alignment of the lumbar and thoracolumbar spine measures using vertebra pelvic angle from L5 to T10.
METHOD(S): Before studying ASD patients, 119 asymptomatic volunteers with full-body, free-standing radiographs were used to identify age-and-PI models of each vertebra pelvic angle (VPA) from L5 to T10, a validated methodology characterizing the detailed shape of the spine. Our study cohort was a registry of surgical primary ASD patients without coronal malalignment (SRS-Schwab Type=N). The formulas developed in the asymptomatic population were applied to the ASD group to calculate an age-and-PI normative spine shape for each patient. Loss of lumbar lordosis was defined as the offset between age-and-PI normative value and pre-operative spino-pelvic alignment. Patients were stratified into four groups by the amount of lordosis lost, ranging from "no loss" to "30degree loss." Paired t-tests were performed to compare actual and normative VPA shapes within each group.
RESULT(S): Out of 1,495 patients enrolled in this registry, 453 were primary cases, and 653 were categorized as a Schwab type N, leading to a cohort of 362 patients (age=64.4+/-13, 57.1% F). Pre-operative alignment demonstrated a large variability with a mean PI-LL of 15degree+/-21, distal LL=31degree+/-15, and PI=55degree+/-13. Compared to their age-and-PI normative values, ASD patients demonstrated a significant lordosis loss of 17degree+/-19 with the following distribution: 14.1% no loss (mean: 0.1+/-2.3), 22.9% with 10degree loss (mean: 9.9+/-2.9), 22.1% with 20degree loss (mean: 20.0+/-2.8), and 29.3% with 30degree loss (mean:33.8+/-6.0). Comparison of the VPAs (and therefore the shape) between each LL group and the normative shape demonstrated that the "no loss" patients had a lumbar spine slightly anterior to the normative shape from L4 to T10 (VPA difference of 2degree). The shape of the "small deformity" group (10degree) superimposed on the normative one from L5 to L2 (VPA with p>0.1) and became anterior at the L1 level. As the lordosis loss increased, the offset between ASD and normative shapes began to propagate to the distal levels and became significant extending caudally to the L3 level for the "20degree loss" group and further down to L4 for the more severe group.
CONCLUSION(S): As the deformity progresses and the loss of lordosis increases, the difference between ASD shape and normative shape happens first proximally and then progresses incrementally caudally with increasing deformity. Understanding the spinal contour and the location of this loss, in addition to regional parameters, may be key to achieving a sustainable correction by identifying optimal and personalized post-operative shape. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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