Faculty Bibliography

BACKGROUND CONTEXT: Chiari malformations (CM) are congenital or acquired hind brain anomalies with resultant cerebellar tonsillar herniation through the foramen magnum. Chiari I malformation consists of herniation of the cerebellar tonsils into the foramen magnum thus crowding the craniocervcial junction. Surgical management is variable among these type 1 patients(pts) based on their presenting symptoms. PURPOSE: Identify complication rates following CM surgery. STUDY DESIGN/SETTING: Retrospective cohort study of (Kids' Inpatient Database) KID. PATIENT SAMPLE: Chiari Malformation Type I. OUTCOME MEASURES: Complication rates, fusion, decompression, duroplasty, laminectomy, LOS, Readmission.
METHOD(S): The KID database was queried for diagnoses of operative Chiari Malformation from 2003-2012 by ICD-9 codes (348.4). Differences in preoperative demographics (age/BMI) and perioperative complication rates between patient cohorts were assessed using Pearson's chi-squared tests and T-tests when necessary. Binary logistic regression were utilized to find significant factors associated with complication rate. Decision tree analysis was utilized for continuous variables predictive of complication rate. Certain surgical procedures were analyzed for their relationship with post-operative outcomes.
RESULT(S): A total of 13,812 CM-1 patients were isolated (10.12 yrs, 0.62 CCI). Of these pts, 8.2% (1,128) received a complication. From 2003 to 2012, the rate of complications for CM-1 pts decreased significantly (9.6%-5.1%) along with surgical rate (33.3%-28.6%), despite the increase in CM diagnosis (36.3%-42.3%; all p<0.05). CM-1 pts who had a complication were younger (9.73+/-6.8 yrs vs 10.2+/-6.3 yrs) and had a lower invasiveness score (0.35+/-1.0 vs 0.41+/-1.0), however; they had a larger CCI (1.10+/-1.6 vs 0.6+/-1.3) than those who did not have a complication (all p<0.05). The most prevalent comorbidities for these pts were cerebrovascular (16.67%), malignancy (11.6%), pulmonary (9.6%), and renal (7.1%; all p<0.05). CM-1 pts who experienced complications had a concurrent diagnosis of syringomyelia (7.1%) and also Scoliosis (3.2%; all p<0.05). CM-1 pts who did not have a complication had a greater surgical rate than those that had a complication (76.4% vs 23.6% p<0.05). Having an interbody instrument, having an invasiveness score>4.25 and receiving a fusion greater than 4 levels were all significant factors associated with receiving a complication postoperatively (p<0.05). The most common complication was nervous system related (2.8%), anemia (2.4%), and acute respiratory distress (2.1%). CM-1 pts that underwent a fusion (3.4% vs 2.1%) had greater complication rates as well as those that underwent a craniotomy (23.2% vs 19.1%; all p<0.05). However, CM-1 pts who underwent a decompression had lower postop complications (21.3% vs 28.9%; all p<0.05). A total of 13,812 CM-1 patients isolated (10.12 yrs, 0.62 CCI). Of these pts, 8.2% (1,128) received a complication. From 2003 to 2012, the rate of complications for CM-1 pts decreased significantly (9.6%-5.1%) along with surgical rate (33.3%-28.6%), despite the increase in CM diagnosis (36.3%-42.3%; all p<0.05). CM-1 pts who had a complication were younger (9.73+/-6.8yrs vs 10.2+/-6.3yrs) and had a lower invasiveness score (0.35+/-1.0 vs 0.41+/-1.0), however; they had a larger CCI (1.10+/-1.6 vs 0.6+/-1.3) than those who did not have a complication (all p<0.05). The most prevalent comorbidities for these pts were cerebrovascular (16.67%), malignancy (11.6%), pulmonary (9.6%), and renal (7.1%; all p<0.05). CM-1 pts who experienced complications had a concurrent diagnosis of syringomyelia (7.1%) and also Scoliosis (3.2%; all p<0.05). CM-1 pts who did not have a complication had a greater surgical rate than those that had a complication (76.4% vs 23.6% p<0.05). Having an interbody instrument, having an invasiveness score>4.25 and receiving a fusion greater than 4 levels were all significant factors associated with receiving a complication postoperatively (p<0.05). The most common complication was nervous system related (2.8%), anemia (2.4%), and acute respiratory distress (2.1%). CM-1 pts that underwent a fusion (3.4% vs 2.1%) had greater complication rates as well as those that underwent a craniotomy (23.2% vs 19.1%; all p<0.05). However, CM-1 pts that underwent a decompression had lower postop complications (21.3% vs 28.9%; all p<0.05).
CONCLUSION(S): Treatment of Chiari malformation has been identified to have improved from 2003 to 2012 with increased identification of diagnosis and decreased complications. Chiari patients undergoing fusions and craniotomies are at a greater risk of postoperative complications especially when the instrumented fusions are performed on >4 levels. 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: Frailty is an increasingly recognized characteristic that has been validated across many studies as influencing operative risk. Utilization of frailty indices can allow for its identification of which spine patients may be too high risk for surgical intervention. This may be especially useful when it comes to surgeries that are minimally invasive and are supposed to have decrease perioperative outcomes. PURPOSE: Identify MIS techniques effects in postoperative outcomes in TLIF patients. STUDY DESIGN/SETTING: Retrospective review of a prospective database. PATIENT SAMPLE: TLIF spine patients. OUTCOME MEASURES: Complications, length of stay (LOS), estimated blood loss (EBL).
METHOD(S): Pts that underwent a lumbar spine procedure in a single-center Comprehensive Spine Quality Database. Pts were stratified based on procedural approach (Open [OP] and Minimally invasive Surgery [MIS]). Frailty was then calculated for each resultant group by using 30 variables with a validated method. Based on these scores, pts were categorized no frailty [NF]: <0.09, frail [F]: 0.09-0.18, and severe frailty [SF] >0.18. Groups were then controlled for surgical invasiveness. Chi-squared tests identified the relationship between complications and length of stay among various frailty states given surgical approach (OP vs MIS). These patients were propensity score matched for levels fused. Hospital acquired complications (HACs) were identified based on frailty groups through the use of chi-squared and t-tests for other surgical factors. A logistic regression analysis identified the association between frailty status and surgical, regarding postoperative (postop) outcomes.
RESULT(S): A total of 1,300 TLIF spine patients were isolated (59yrs, 29.3kg/m2). After PSM for levels fused, there were 338 pts for both MIS and OP. MIS pts were older (56.1 vs 53.3; p<0.05) than Op pts and had similar BMI's (29.1 vs 29.7; respectively). However, OP received more posterior approaches and less anterior approaches than MIS pts (p<0.05). By surgical factors: MIS and OP patients had similar LOS (3 vs 2.9days) and EBL (282.8 vs 251.5cc) but differed by Op time (195.7 vs 247.1; p<0.05) respectively. Further breakdown by frailty displayed statistical significance between MIS and OP patients with MIS pts having more F (16% vs 12%) and SF pts (4.3% vs 1.9%) than OP (all p<0.05). FMIS patients had lower postop neurologic complications as compared to FOP pts (4.63% vs 14.8%). However, SFMIS patiens had more post-operative complications than SFOP pts (55.2% vs 23.1%) and increased a pt's likelihood of being SFMIS by 5.4x's (all p<0.05).
CONCLUSION(S): This study displays that when frailty status is taken into account, TLIF MIS patients benefit from this procedure type when analyzed against neurologic complications. However, these patients were seen to suffer more from postop complications but did not differ on any other specific complications or surgical variables. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: To make the 40-factor adult spinal deformity frailty index (ASD-FI) more practical for use in clinical setting, a recent study proposed a modified, 8-factor frailty index (mASD-FI). The mASD-FI quantifies frailty of ASD patients on a scale from 0 to 21, with higher scores indicating greater frailty. While the mASD-FI has been shown to correlate with preoperative pain and disability, its relationship with postoperative outcomes has not been investigated. PURPOSE: Assess the relationship between mASD-FI score and clinical outcomes after ASD-corrective surgery. STUDY DESIGN/SETTING: Retrospective cohort study PATIENT SAMPLE: A total of 509 ASD patients OUTCOME MEASURES: Length of stay (LOS), complications, health-related quality of life (HRQL) questionnaires: ODI, SRS-22r, EQ-5D, SF-36 Physical Component Score (PCS).
METHOD(S): ASD patients (scoliosis>=20degree, SVA>=5cm, PT>=25degree, or TK >=60degree) with available mASD-FI scores and HRQL data at pre- and 2-years postop intervals were included. Patients were stratified by mASD-FI score using published cutoffs: not frail (<7), frail (7-12), severely frail (>12). Analysis of variance (ANOVA) assessed differences in demographics, surgical factors, and HRQL across frailty groups. Linear regression assessed the relationship between mASD-FI score and postop clinical outcomes (LOS, HRQL scores). Binary logistic regression assessed the relationship between frailty category and odds of complication or reoperation (results presented: odds ratio [95% confidence interval]).
RESULT(S): A total of 509 ASD patients were included (59+/-14yrs, 79%F, BMI: 27.7+/-6.0 kg/m2). The overall cohort presented with moderate baseline deformity: SVA (83.7mm+/-71), PT (12.7degree+/-10.8), PI-LL (43.1degree+/-21.1). Mean preop mASD-FI score was 7.2+/-5.0, and breakdown by frailty category was: not frail (50.3%), frail (34.0%), severely frail (15.7%). Preop age, BMI, and Charlson Comorbidity Index score all increased across increasing frailty categories (all p<0.001); however, fusion length (p=0.247) and rates of osteotomy (p=0.731) did not. At baseline, increasing frailty was associated with inferior ODI, EQ-5D, SRS-22r, SF-36 PCS, and NRS Back and Leg pain scores (all p<0.001). Following surgery, length of stay increased with increasing frailty category (6.9 days, 7.9 days, 9.6 days, p<0.001). Complication rates increased with frailty (57.6%, 64.4%, 78.7%, p<0.001). Increasing frailty was also associated with inferior postoperative outcomes for ODI (19.9, 31.8, 41.2), SRS (3.9, 3.6, 3.2), EQ-5D (0.84, 0.80, 0.74), and SF-36 PCS (44.2, 36.5, 32.6, all p<0.001). Higher preop mASD-FI scores predicted inferior postoperative scores for ODI (R2=0.193), SRS (R2=0.132), EQ-5D (R2=0.156) and SF-36 (R2=0.198). Controlling for complication incidence, baseline mASD-FI score still predicted postop scores for ODI, SRS, EQ-5D, and SF-36 (all p<0.001). Frailty also predicted higher odds of revision surgery (1.6 [1.1-2.5]) and complication (2.2 [1.5-3.2]), including infection (2.1 [1.1-3.9]), wound (2.0 [1.3-3.0]), and implant-related (2.2 [1.4-3.5]) complications. Severe frailty was associated with even greater odds of revision (2.0 [1.1-3.4]) and complication (2.8 [1.5-5.0]), including infection (2.5 [1.3-5.0]) and radiographic (2.3 [1.4-3.8]) complications. Operative treatment was associated with significant pre- to postop changes in frailty (7.2+/-5.0 to 4.9+/-4.4, p<0.001).
CONCLUSION(S): Greater preoperative frailty, as assessed by mASD-FI score, was associated with significantly greater LOS and inferior postoperative health-related quality of life across multiple outcomes assessment instruments. Frailty status was associated with increased odds of reoperation, complication, and infection. Severely frail patients showed the greatest risk of experiencing an adverse event. These results suggest the mASD-FI may have utility as a preoperative risk assessment tool. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Operative treatment of adult spinal deformity (ASD) can be very challenging with high complication rates. Despite these challenges it's well established that pts benefit from such treatment. However, the surgical outcomes for pts with mild scoliosis and age appropriate sagittal alignment have not been reported. PURPOSE: To determine if patients (pts) with mild scoliosis and age appropriate sagittal alignment have favorable outcomes following surgical correction. STUDY DESIGN/SETTING: Retrospective review of a prospective, multicenter ASD database. PATIENT SAMPLE: ASD patients: operative pts age>=18, and all preoperartive pelvic tilt (PT), mismatch between pelvic incidence and lumbar lordosis (PI-LL), and C7 sagittal vertical axis (SVA) within established age adjusted parameters with minimum 2-year follow up. A subanalysis for pts with max coronal cobb angle 10-30degree (mild scoli) was done. OUTCOME MEASURES: Health-related quality of life (HRQOL) scores: Oswestry Disability Index (ODI), Short form-36(SF36), Scoliosis Research Society (SRS22), back/leg pain numerical rating scale (NRS) and minimum clinically important difference (MCID)/substantial clinical benefit (SCB). Radiographic values: max coronal cobb angle, coronal C7 plumb line, PT, PI-LL, thoracic kyphosis (TK), SVA. Demographic, frailty, surgical and complications data were collected.
METHOD(S): Two-year and baseline HRQOL/radiographic data were compared.
RESULT(S): A total of 103 pts were included from 667 operative patients (89.3% female, avg age 59.8+/-13.1yrs). Of the 103 pts, 29 (28.2%) had max preop coronal cobb angle 10-30degree. Two-year max coronal cobb angle and C7 coronal plumb were significantly improved compared to baseline (p<0.001 for both the overall cohort and mild scoli). All 2yr HRQOL measures were significantly improved compared to baseline(p<0.001) for both groups. 33.3-81.5%% of mild scoli pts met either MCID/SCB for all HRQOL. In mild scoli pts, 62.1% had min one complication, 27.6% had a major complication with 24.1% requiring a revision.
CONCLUSION(S): Pts with mild scoliosis and sagittal alignment within age appropriate parameters benefit from surgical correction at 2 years postop both radiographically and clinically including 81.5% meeting MCID for SRS pain despite having high complication rates. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Due to the complexity and invasiveness of deformity correction, poor outcomes are often associated. Currently, it is unknown what factors predict an outcome which operation may not be warranted (reoperation, major complications, clinical deterioration). PURPOSE: To investigate what patient factors justify determining a patient ineligible for a deformity correction. STUDY DESIGN/SETTING: Retrospective review of a prospective, consecutively enrolled adult spinal deformity (ASD) database. PATIENT SAMPLE: Operative patients with complete 2-year HRQL and radiographic data were included. OUTCOME MEASURES: HRQLs: Oswestry Disability Index (ODI), complications; reoperations.
METHOD(S): Patients >18yrs undergoing surgery for ASD (scoliosis >=20degree, SVA >=5cm, PT >=25degree, or TK >=60degree). An unsatisfactory outcome was defined by the following categories met at 2Y: (1) clinical: deteriorating in ODI at 2Y follow-up (2) complications/reop: having a reoperation and major complication were deemed unacceptable for surgery (NoOp). Baseline demographic, clinical and radiographic information were utilized through univariate/multivariate analyses to assess predictive factors of NoOp patients in adult spinal deformity patients. Multivariate regression with backward model selection was employed to create a model for when not to operate.
RESULT(S): A total of 633 ASD patients (59.9 years, 79% F, 27.7 kg/m2, CCI: 1.74) were included. By approach, 0.6% were anterior, 69.7% posterior and 29.5% combined approaches, with a total number of levels fused as 7.5+/-2.1. Baseline severe Schwab modifier incidence (++): 39.2% PI-LL, 28.8% SVA, 28.9% PT. 15.5% of patients deteriorated in ODI by 2 years, while 7.6% underwent a reoperation and had a major complication. This categorized 11 (1.7%) of patients in the total cohort as NoOp. NoOp patients had were more comorbid in terms of arthritis (73%) heart disease (36%) and kidney disease (18%), p<0.001. Surgically, NoOp patients had an overall greater EBL (4431ccs), underwent more osteotomies (91%), specifically Ponte (36%) and Three Column Osteotomies (55%), which occurred more at L2(91%). NoOp patients underwent more PLIFs (45%) and had more blood transfusion units (2641ccs), all p<0.050. The multivariate regression predicting the NoOp ASD group determined a combination of a baseline DRAM score in the 75th percentile, having arthritis and kidney disease, a baseline right lower extremity motor score <=3, cSVA >65mm, C2 slope >30.2degree, CTPA >5.5degree for an R2 value of 0.535 (p<0.001).
CONCLUSION(S): When addressing adult spine deformities, a negative outcome of clinical deterioration, major complications, and reoperations are exceedingly rare, but do occur. This tends to occur in severely comorbid patients with major baseline psychological distress scores, severe neurologic dysfunction and concomitant cervical malalignment not addressed at surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Substantial adult spinal deformity (ASD) research has focused on sagittal plane radiological assessment and emphasized the importance of sagittal correction on patient-reported outcomes. It seems less attention has been given to evaluation of ASD in the coronal plane. However, recent ASD studies have demonstrated baseline global coronal malalignment (GCM; substantial displacement of the C7 coronal plumb line from midsacrum) in up to 35% of patients. Moreover, GCM can worsen postoperatively or may occur as an iatrogenic complication in previously balanced patients. Collectively, this may suggest that the associated clinical impact of GCM on ASD surgical outcomes has been underestimated. Currently, few reports focus on surgical outcomes in ASD patients with GCM. PURPOSE: Our objective was to assess treatment outcomes and complication rates associated with ASD surgery in the subset of patients with severe GCM. STUDY DESIGN/SETTING: Retrospective review of a prospectively collected multicenter consecutive case registry. PATIENT SAMPLE: Enrollment required: age >=18 years, scoliosis >=20degree, sagittal vertical axis (SVA) >=5cm, pelvic tilt >=25degree, and/or thoracic kyphosis >=60degree. OUTCOME MEASURES: Radiographic correction (both standard coronal and sagittal spinopelvic deformity measurements) and health-related quality of life (HRQL) outcomes, which included Oswestry Disability Index (ODI), Short Form-36 (SF-36) scores, Scoliosis Research Society-22 (SRS-22) scores, and back/leg pain numerical rating scale (NRS) scores.
METHOD(S): Surgically treated ASD patients with severe GCM (coronal C7PL-midsacral offset magnitude >=1 SD above the mean) were identified. Baseline and follow-up radiographic and HRQL outcomes were analyzed. Percentages of patients achieving minimal clinically important difference (MCID) and substantial clinical benefit (SCB) were assessed. Demographic, frailty, surgical, and complications data were collected. The primary focus for analysis was on patients who reached minimum 2-year follow-up.
RESULT(S): Of 691 potentially eligible operative patients (mean GCM = 4+/-3 cm), 80 met criteria for severe GCM >= 7cm. Of these 80 patients, 62 (78%, mean age 64 years, 81% women) had minimum 2-year follow-up. Baseline frailty score was 3.9+/-1.5 (indicating patients were frail) and 48% had prior spine fusion. Surgical data included: posterior-only (58%), mean fusion 13 levels, sacroiliac fixation (97%), and three-column osteotomy (36%). Postoperative biplane alignment improved significantly (p<0.001): GCM 11 to 4 cm, lumbar Cobb 30degree to 11degree, C7-S1 SVA 13 to 4 cm, and PI-LL 31degree to 5degree. Overall HRQL improved significantly (p<=0.003): ODI 51 to 37, SF-36 PCS 29 to 37, SRS-22r 2.6 to 3.5, and back/leg pain NRS 7 to 4 and 5 to 3, respectively. Thresholds for MCID/SCB were met in 43-83% of patients. A total of 89 complications were reported (34 minor/55 major), and 45 (73%) patients had >=1 complication (most commonly rod fracture [19%] and PJK [18%]). There were 34 reoperations in 22 (36%) patients (most common indications rod fracture/PJK). The 18 patients who did not achieve 2-year follow-up had a mean of 0.63 years follow-up, and the types of complications encountered in these 18 patients were comparable to those encountered in patients with 2-year follow-up.
CONCLUSION(S): ASD surgery for patients with severe GCM is associated with significant improvements in biplane alignment and HRQL outcome measures despite high complication rates. 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: For surgical adult spinal deformity (ASD) patients, determining optimal restoration of alignment and spinal shape have been increasingly studied. Temporally, the SRS-Schwab classification system was the first severity categorization system. Next, the age-adjusted alignment was proposed, followed by Roussouly classification, and then a spinal proportionality score to minimize mechanical complications. These additional layers of complexity add to an already technically challenging and high risk case. What hasn't been determined is the incremental benefit of these. PURPOSE: To assess the incremental benefits of adding ASD surgical corrective measures on patient-reported outcomes. STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: This study included 732 ASD patients. OUTCOME MEASURES: Complications; health related quality of life (HRQL).
METHOD(S): ASD patients with baseline (BL) and 2-year postoperative (2Y) data included. Patients were classified by the four proposed corrective alignment measures: SRS-Schwab: PT, SVA and PI-LL(0, +, and ++); Age-adjusted: PT, PI-LL, and SVA-adjusted ideal; Roussouly type: 'Match' or 'Mismatch,' their theoretical type; spinal proportionality: sagittal disproportion score out of 13. Alignment improvement: SRS-Schwab 0 or decrease in severity, Age-adjusted ideal match, Roussouly theoretical Match, and decrease in proportion. To assess the incremental benefit of layers of complexity, patients were separated into 4 groups: the first layer (1st) solely improving in SRS-Schwab at 2Y, 2nd as Schwab improvement and matching Age-adjusted, 3rd as the two prior with matching of Roussouly, and 4th improvement in Schwab and proportionality, as well as matching both Age-adjusted ideals and Roussouly. Comparison was accomplished with means comparison tests and chi-squared analyses.
RESULT(S): A total of 732 ASD patients (57.5yrs, 82.4%F, 27kg/m2) included. SRS-Schwab BL: PI-LL (++:32.9%), SVA (++: 23%), PT (++:24.6%). At 2 year, 54.9% improved in PT modifier, 71% SVA, 74.3% PI-LL. For Age-adjusted ideal, 28% met PT ideal, 18.8% PI-LL, and 31.3% SVA. By 2 years, 44.7% matched Roussouly types. At 2 years, 30.8% improved in spine proportion. According to layer of correction complexity groups: 640 (87.4%) met criteria for first, 517 (70.6%) 2nd, 176 (24%) 3rd, and 55 (7.5%) 4th. When comparing the incremental adding of the second layer, or age-adjusted ideals to Schwab improvement, complications and HRQLs were similar (p>0.05). Addition of Roussouly (third) had less mechanical complications and PJK (48.3%), and met MCID for PCS and SRS-Mental (p<0.05) more compared to the second tiered. The addition of the spinal proportion score (fourth) compared to the third, met MCID for ODI (44.2% vs third: 28.3%, p=0.011) and SRS-Appearance (70.6% vs 44.8%, p<0.001) more. When assessing baseline components included in the classifications, PI, PT, PI-LL and SVA were smallest in the third group (p<0.020). Invasiveness was the greatest in the fourth layer (p<0.001). Mechanical complications and PJK occurred to a greater extent in the first and second complexity groups (p=0.024). According to HRQL follow-up, the fourth layer met MCID more than all other complexity groups for SRS-22 Appearance (p=0.002) and ODI (p=0.085).
CONCLUSION(S): Consideration of multiple complex realignment techniques, taking into account deformity severity, age, shape, and spinal proportion, may assist in optimizing patient-reported outcomes following spinal realignment surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Traditional iliac (IS) and S2-alar-iliac (S2AI) pelvic fixation methods have unique technical characteristics in their application, and result in varied biomechanical and anatomic impact. These differences may lead to variance in lumbopelvic fixation failure types and rates. PURPOSE: We intended to evaluate the influence of type of iliac fixation utilized for adult spinal deformity (ASD) correction on the frequency and manner of lumbopelvic fixation failure. STUDY DESIGN/SETTING: Retrospective review of prospective, multicenter ASD database. PATIENT SAMPLE: This study included 410 patients. OUTCOME MEASURES: HRQL (ODI, SF-36, NRS), rod fracture, screw fracture, screw loosening, revision surgery, pseudarthrosis METHODS: Inclusion criteria included ASD (coronal Cobb>=20degree, sagittal vertical axis (SVA) >=5cm, pelvic tilt >=25degree and/or thoracic kyphosis >60degree) >= 18 years old, 2yr follow-up, and >5 level fusion with pelvic fixation. Cohort subdivided by type of pelvic fixation (IS vs S2AI). Loosening was defined by lucency around the screw shank on radiographs. Univariate testing was performed using t-tests and chi-squared tests. Multivariate logistic regression, accounting for significant confounders, was used to examine differences between the two groups for screw loosening/fracture, rod fracture, and revision surgery. Level of significance = p<0.05.
RESULT(S): Of the total of 1422 patients, 410 met inclusion criteria (IS=287, S2AI=131). The two groups had similar age, BMI, baseline co-morbidities, and number of levels fused (p>0.05), as well as similar baseline HRQLs (SF-36, ODI, SRS-22, NRS leg and back, p>0.05) and deformity (PT, PI-LL, SVA, p>0.05). Patients in the IS group had a higher proportion of unilateral fixation compared to S2AI group (12.9% vs 5.6%; p=0.001). The overall pelvic fixation failure rate (screw loosening/screw fracture/rod fracture) was 29.4%. Loosening of pelvic fixation occurred in 13.4% of patients, and was more prevalent in the S2AI fixation group (OR 2.74, p=0.001). The rate of S1 screw loosening was 2.9%, and more likely to occur in the S2AI group (OR 4.17, p=0.045). The rate of pelvic fixation fracture in the overall cohort was 2.3%, with no difference between groups (p=0.37). Rod fracture occurred in 14.1% below L4, with a trend toward less occurrence in the S2AI group (OR 0.47, p=0.06). Revision surgery was required in 22.7% of our cohort, with no difference between groups (p=0.449). Patients with failure of the pelvic fixation had less improvement in their HRQL at 2years (PCS 7.69 vs 10.46 p=0.028; SRS 0.83 vs 1.03 p=0.019; ODI 12.91 vs 19.77 p=0.0016).
CONCLUSION(S): Pelvic fixation is commonly used in long segment adult spinal deformity surgery to improve the rate of L5-S1 fusion and protect from construct failure at the lumbosacral junction. Our results demonstrate a substantial rate of pelvic fixation hardware issues following ASD correction. Lumbopelvic fixation failure occurred at a rate of 29.4% following surgical correction of ASD that involved iliac fixation and was associated with diminished clinical outcomes. Additionally, S2AI screws were more likely to demonstrate loosening, but less commonly associated with rod fractures. Patients who experienced failure of their pelvic fixation had less improvement in their HRQL two years postoperatively. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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