After Adult Spinal Deformity Patients Research Articles

Spinopelvic fixation failure in the adult spinal deformity population: systematic review and meta-analysis.

Despite modern fixation techniques, spinopelvic fixation failure (SPFF) after adult spinal deformity (ASD) surgery ranges from 4.5 to 38.0%, with approximately 50% requiring reoperation. Compared to other well-studied complications after ASD surgery, less is known about the incidence and predictors of SPFF. Given the high rates of SPFF and reoperation needed to treat it, the purpose of this systematic review and meta-analysis was to report the incidence and failure mechanisms of SPF after ASD surgery. The literature search was executed across four databases: Medline via PubMed and Ovid, SPORTDiscus via EBSCO, Cochrane Library via Wiley, and Scopus. Study inclusion criteria were patients undergoing ASD surgery with spinopelvic instrumentation, report rates of SPFF and type of failure mechanism, patients over 18years of age, minimum 1-year follow-up, and cohort or case-control studies. From each study, we collected general demographic information (age, gender, and body mass index), primary/revision, type of ASD, and mode of failure (screw loosening, rod breakage, pseudarthrosis, screw failure, SI joint pain, screw protrusion, set plug dislodgment, and sacral fracture) and recorded the overall rate of SPF as well as failure rate for each type. For the assessment of failure rate, we required a minimum of 12months follow-up with radiographic assessment. Of 206 studies queried, 14 met inclusion criteria comprising 3570 ASD patients who underwent ASD surgery with pelvic instrumentation (mean age 65.5 ± 3.6years). The mean SPFF rate was 22.1% (range 3-41%). Stratification for type of failure resulted in a mean SPFF rate of 23.3% for the pseudarthrosis group; 16.5% for the rod fracture group; 13.5% for the iliac screw loosening group; 7.3% for the SIJ pain group; 6.1% for the iliac screw group; 3.6% for the set plug dislodgement group; 1.1% for the sacral fracture group; and 1% for the iliac screw prominence group. The aggregate rate of SPFF after ASD surgery is 22.1%. The most common mechanisms of failure were pseudarthrosis, rod fracture, and iliac screw loosening. Studies of SPFF remain heterogeneous, and a consistent definition of what constitutes SPFF is needed. This study may enable surgeons to provide patient specific constructs with pelvic fixation constructs to minimize this risk of failure.

Knee flexion compensation in postoperative adult spinal deformity patients: implications for sagittal balance and clinical outcomes.

To determine whether maintaining good sagittal balance with significant knee flexion (KF) constitutes a suboptimal outcome after adult spinal deformity (ASD) correction. This single-center, single-surgeon retrospective study, assessed ASD patients who underwent posterior spinal fusion between 2014 and 2020. Inclusion criteria included meeting at least one of the following: PI-LL ≥ 25°, T1PA ≥ 20°, or CrSVA-H ≥ 2cm. Those with lower-extremity contractures were excluded. Patients were classified into four groups based on their 6-week postoperative cranio-hip balance and KF angle, and followed for at least 2 years: Malaligned with Knee Flexion (MKF+) (CrSVA-H > 20mm + KFA > 10), Malaligned without Knee Flexion (MKF-) (CrSVA-H > 20mm + KFA < 10), Aligned without Knee Flexion (AKF-) (CrSVA-H < 20mm + KFA < 10), and Aligned with Knee Flexion (AKF+) (CrSVA-H < 20mm + KFA > 10). The primary outcomes of this study included one and two year reoperation rates. Secondy outcomes included clinical and patient reported outcomes. 263 patients (mean age 60.0 ± 0.9 years, 74.5% female, and mean Edmonton Frailty Score 3.3 ± 0.2) were included. 60.8% (160/263 patients) exhibited good sagittal alignment at 6-week postop without KF. Significant differences were observed in 1-year (p = 0.0482) and 2-year reoperation rates (p = 0.0374) across sub-cohorts, with the lowest and highest rates in the AKF- cohort (5%, n = 8) and MKF + cohort (16.7%, n = 4), respectively. Multivariable Cox regression demonstrated the AKF- cohort exhibited significantly better reoperation outcomes compared to other groups: AKF + (HR: 5.24, p = 0.025), MKF + (HR: 31.7, p < 0.0001), and MKF- (HR: 11.8, p < 0.0001). Our findings demonstrate that patients relying on knee flexion compensation in the early postoperative period have inferior outcomes compared to those achieving sagittal balance without knee flexion. When compared to malaligned patients, those with CrSVA-H < 20mm and KFA > 10 degrees experience fewer early reoperations but similar delayed reoperation rates. This insight emphasizes the importance of considering knee compensation perioperatively when managing sagittal imbalance in clinical practice.

Incidence, mechanism, and protective strategies for 2-year pelvic fixation failure after adult spinal deformity surgery with a minimum six-level fusion.

The purpose of this study was to determine the incidence, mechanism, and potential protective strategies for pelvic fixation failure (PFF) within 2 years after adult spinal deformity (ASD) surgery. Data for ASD patients (age ≥ 18 years, minimum of six instrumented levels) with pelvic fixation (S2-alar-iliac [S2AI] and/or iliac screws) with a minimum 2-year follow-up were consecutively collected (2015-2019). Patients with prior pelvic fixation were excluded. PFF was defined as any revision to pelvic screws, which may include broken rods across the lumbosacral junction requiring revision to pelvic screws, pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws, a broken or loose pelvic screw, or sacral/iliac fracture. Patient information including demographic data and health history (age, sex, BMI, smoking status, American Society of Anesthesiologists score, osteoporosis), operative (total instrumented levels [TIL], three-column osteotomy [3CO], interbody fusion), screw (iliac, S2AI, length, diameter), rod (diameter, kickstand), rod pattern (number crossing lumbopelvic junction, lowest instrumented vertebra [LIV] of accessory rod[s], lateral connectors, dual-headed screws), and pre- and postradiographic (lumbar lordosis, pelvic incidence, pelvic tilt, major Cobb angle, lumbosacral fractional curve, C7 coronal vertical axis [CVA], T1 pelvic angle, C7 sagittal vertical axis) parameters was collected. All rods across the lumbosacral junction were cobalt-chrome. All iliac and S2AI screws were closed-headed tulips. Both univariate and multivariate analyses were performed to determine risk factors for PFF. Of 253 patients (mean age 58.9 years, mean TIL 13.6, 3CO 15.8%, L5-S1 interbody 74.7%, mean pelvic screw diameter/length 8.6/87 mm), the 2-year failure rate was 4.3% (n = 11). The mechanisms of failure included broken rods across the lumbosacral junction (n = 4), pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws (n = 3), broken pelvic screw (n = 1), loose pelvic screw (n = 1), sacral/iliac fracture (n = 1), and painful/prominent pelvic screw (n = 1). A higher number of rods crossing the lumbopelvic junction (mean 3.8 no failure vs 2.9 failure, p = 0.009) and accessory rod LIV to S2/ilium (no failure 54.2% vs failure 18.2%, p = 0.003) were protective for failure. Multivariate analysis demonstrated that accessory rod LIV to S2/ilium versus S1 (OR 0.2, p = 0.004) and number of rods crossing the lumbar to pelvis (OR 0.15, p = 0.002) were protective, while worse postoperative CVA (OR 1.5, p = 0.028) was an independent risk factor for failure. The 2-year PFF rate was low relative to what is reported in the literature, despite patients undergoing long fusion constructs for ASD. The number of rods crossing the lumbopelvic junction and accessory rod LIV to S2/ilium relative to S1 alone likely increase construct stiffness. Residual postoperative coronal malalignment should be avoided to reduce PFF.

Assessing the influence of modifiable patient-related factors on complication rates after adult spinal deformity surgery.

Postoperative complication rates remain relatively high after adult spinal deformity (ASD) surgery. The extent to which modifiable patient-related factors influence complication rates in patients with ASD has not been effectively evaluated. The aim of this retrospective cohort study was to evaluate the association between modifiable patient-related factors and complications after corrective surgery for ASD. ASD patients with two-year data were included. Complications were categorized as follows: any complication, major, medical, surgical, major mechanical, major radiological, and reoperation. Modifiable risk factors included smoking, obesity, osteoporosis, alcohol use, depression, psychiatric diagnosis, and hypertension. Patients were stratified by the degree of baseline deformity (low degree of deformity (LowDef)/high degree of deformity (HighDef): below or above 20°) and age (Older/Younger: above or below 65 years). Complication rates were compared for modifiable risk factors in each age/deformity group, using multivariable logistic regression analysis to adjust for confounders. A total of 480 ASD patients met the inclusion criteria. By two years, complication rates were 72% ≥ one complication, 28% major, 21% medical, 27% surgical, 11% major radiological, 8% major mechanical, and 22% required reoperation. Younger LowDef patients with osteoporosis were more likely to suffer either a major mechanical (odds ratio (OR) 5.9 (95% confidence interval (CI) 1.1 to 36.9); p = 0.048) or radiological complication (OR 7.0 (95% CI 1.9 to 25.9); p = 0.003). Younger HighDef patients were much more likely to develop complications if obese, especially major mechanical complications (OR 2.8 (95% CI 1.1 to 8.6); p = 0.044). Older HighDef patients developed more complications when diagnosed with depression, including major radiological complications (OR 3.5 (95% CI 1.1 to 10.6); p = 0.033). Overall, a diagnosis of depression proved to be a risk factor for the development of major radiological complications (OR 2.4 (95% CI 1.3 to 4.5); p = 0.005). Certain modifiable patient-related factors, especially osteoporosis, obesity, and mental health status, are associated with an increased risk of complications after surgery for spinal deformity. Surgeons should look for these conditions when assessing a patient for surgery, and optimize them to the fullest extent possible before proceeding to surgical correction so as to minimize the prospect of postoperative morbidity.Cite this article: Bone Joint J2022;104-B(11):1249-1255.

The Impact of Upper Instrumented Vertebra Orientation on Proximal Junctional Kyphosis: A Novel and Fixed Parameter, Fused Spinopelvic Angle.

A retrospective study. To evaluate the impact of upper instrumented vertebra (UIV) orientation including the fused spinopelvic angle (FSPA) on proximal junctional kyphosis (PJK). PJK is a challenging complication after adult spinal deformity (ASD) surgery. Some studies proposed UIV orientation act as a risk factor of PJK, but there remain debates because UIV orientation is changed by position. Therefore, we investigated the relationship between the FSPA, a novel parameter for the relationship between UIV and pelvis which did not change by position, and PJK. ASD patients who underwent long-segment fusion to the pelvis and followed up for more than two years were included. Comparative analysis was performed on spinopelvic parameters including UIV orientation parameters (UIV slope angle and FSPA) between PJK and non-PJK group. Binary regression analysis was conducted to find out the risk factors for PJK. And correlation analysis was conducted to find out the parameters that affect the FSPA. A total of 190 patients were included. PJK incidence was 13.2% (25/190). PJK group showed a significantly greater postoperative UIV slope (21.3° vs. 18.8°, P =0.041) and significantly lesser postoperative FSPA (-0.9° vs. 4.5°, P <0.001). In binary regression analysis, only FSPA acted as a risk factor of PJK (odds ratio=0.920, P =0.004). The FSPA has strong positive correlation with pelvic incidence (PI)-lumbar lordosis (LL) ( r =0.666, P <0.001) and negative correlation with lordosis distribution index (LDI) ( r =-0.228, P =0.004). The FSPA is a fixed parameter which is not dependent on position. A reduction of the FSPA increases the risk for PJK. The FSPA can be adjusted through PI-LL and LDI. Thus, surgeons should increase the FSPA by adjusting the PI-LL and LDI during ASD surgery to prevent PJK.

Surgical site infection is a major risk factor of pseudarthrosis in adult spinal deformity surgery

BACKGROUND CONTEXTDespite the evidence in appendicular skeletal surgery, the effect of infection on spinal fusion remains unclear, particularly after Adult Spinal Deformity (ASD) surgery. PURPOSEThe purpose of this study was to determine the impact of surgical site infection (SSI) in ASD surgery fusion rates and its association with other risks factors of pseudarthrosis. STUDY DESIGNWe conducted an international multicenter retrospective study on a prospective cohort of patients operated for spinal deformity. PATIENT SAMPLEA total of 956 patients were included (762 females and 194 males). OUTCOME MEASURESPatient's preoperative characteristics, pre and postoperative spinopelvic parameters, surgical variables, postoperative complications and were recorded. Surgical site infections were asserted in case of clinical signs associated with positive surgical samples. Each case was treated with surgical reintervention for debridement and irrigation. Presence of pseudarthrosis was defined by the association of clinical symptoms and radiological signs of nonfusion (either direct evidence on CT-scan or indirect radiographic clues such as screw loosening, rod breakage, screw pull out or loss of correction). Each iterative surgical intervention was collected. METHODSUnivariate and multivariate analysis with logistic regression models were performed to evaluate the role of risk factors of pseudarthrosis. RESULTSNine hundred fifty-six surgical ASD patients with more than two years of follow-up were included in the study. 65 of these patients were treated for SSI (6.8%), 138 for pseudarthrosis (14.4%), and 28 patients for both SSI and pseudarthrosis.On multivariate analysis, SSI was found to be a major risk factor of pseudarthrosis (OR=4.4; 95% CI=2.4,7.9) as well as other known risks factors: BMI (OR=1.1; 95% CI=1.0,1.1), smoking (OR=1.6; 95% CI=1.1,2.9), performance of Smith-Petersen osteotomy (OR = 1.6; 95% CI 1.0,2.6), number of vertebrae instrumented (OR=1.1; 95% CI=1.1,1.2) and the caudal level of fusion, with a distal exponential increment of the risk (OR max for S1=6, 95% CI=1.9,18.6). CONCLUSIONSSI significantly increases the risk of pseudarthrosis with an OR of 4.4.

159. Impact of smoking status on early and late outcomes after adult spinal deformity surgery

159. Impact of smoking status on early and late outcomes after adult spinal deformity surgery

160. Survival analysis using fusion status after adult spinal deformity (ASD) surgery with minimum 4-year follow-up

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 =20°, sagittal vertical axis (SVA) =5cm, pelvic tilt =25°, or thoracic kyphosis =60°. 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). METHODS 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 [DBM], 3-column osteotomy [3CO]) were assessed to identify potential predictors of nonunion (grade C or D), which were then analyzed using Kaplan-Meier survival curves and log-rank comparisons. RESULTS A total of 227 patients achieved minimum 4-year follow-up and were included (age 58±14y, 82% women, BMI 27±5kg/m2, 40% prior spine surgery, ASD-FI 0.31 [frail], 15% osteoporosis). Index operations had 12±4 posterior levels, 70% iliac fixation, 62% IBF, 76% had BMP, 33% had DBM (of which 52% also had BMP), and 15% had 3CO. At final follow-up, 61 patients (27%) demonstrated nonunion (grade C or D). Older age (61±14 vs 57±14, p=0.015), no BMP usage (p 60 years) had significantly higher probability of nonunion (log-rank test p=0.024), and BMP had protective effect (log-rank test p 0.05). CONCLUSIONS This study demonstrated that older age (>60 years) was associated with significantly higher rates of nonunion at long-term follow-up (4 years) after ASD surgery, and that use of BMP had significant protective effect against this complication. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Prior reports have focused on grading fusion status after adult spinal deformity (ASD) surgery; however, few focused on fusion status after 4-years postop. To identify risk factors for nonunion in a prospective cohort of ASD patients with long-term follow-up (=4 years). Prospective multicenter observational series. Database enrollment required age =18 years, scoliosis =20°, sagittal vertical axis (SVA) =5cm, pelvic tilt =25°, or thoracic kyphosis =60°. 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). 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 [DBM], 3-column osteotomy [3CO]) were assessed to identify potential predictors of nonunion (grade C or D), which were then analyzed using Kaplan-Meier survival curves and log-rank comparisons. A total of 227 patients achieved minimum 4-year follow-up and were included (age 58±14y, 82% women, BMI 27±5kg/m2, 40% prior spine surgery, ASD-FI 0.31 [frail], 15% osteoporosis). Index operations had 12±4 posterior levels, 70% iliac fixation, 62% IBF, 76% had BMP, 33% had DBM (of which 52% also had BMP), and 15% had 3CO. At final follow-up, 61 patients (27%) demonstrated nonunion (grade C or D). Older age (61±14 vs 57±14, p=0.015), no BMP usage (p 60 years) had significantly higher probability of nonunion (log-rank test p=0.024), and BMP had protective effect (log-rank test p 0.05). This study demonstrated that older age (>60 years) was associated with significantly higher rates of nonunion at long-term follow-up (4 years) after ASD surgery, and that use of BMP had significant protective effect against this complication.

Rates of Loosening, Failure, and Revision of Iliac Fixation in Adult Deformity Surgery.

Retrospective cohort review of a prospective multicenter database. Identify rates and variations in lumbopelvic fixation failure after adult spinal deformity (ASD) correction. Traditional iliac (IS) and S2-alar-iliac (S2AI) pelvic fixation methods have unique technical characteristics for their application, and result in varied bio-mechanical and anatomic impact. These differences may lead to variance in lumbopelvic fixation failure types/rates. ASD patients undergoing correction with more than five level fusion and pelvic fixation, separated by pelvic fixation type (IS vs. S2AI). Fixation fracture or loosening assessed radiographically (Figure 1). 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 set at P< 0.05. Four hundred eighteen of 1422 patients were included (IS = 287, S2AI = 131). The groups had similar age, body mass index (BMI), baseline comorbidities, number of levels fused (P>0.05), baseline health related quality of life measures (HRQLs) (short form survey-36, Oswestry Disability Index [ODI], Scoliosis Research Society [SRS-22], numeric rating scale [NRS] leg and back, P>0.05) and deformity (pelvic tilt [PT], pelvic incidence-lumbar lordosis [PI-LL], and sagittal vertical axis [SVA], P> 0.05). The IS group had more unilateral fixation versus S2AI (12.9% vs. 6%; P = 0.02). The overall lumbopelvic fixation failure rate was 23.74%. Pelvic fixation (13.4%) and S1 screw (2.9%) loosening was more likely with S2AI (odds ratio [OR] 2.63, P = 0.001; OR 6.05, P = 0.022). Pelvic screw (2.3%) and rod fracture (14.1%) rates similar between groups but trended toward less occurrence with S2AI (OR 0.47, P= 0.06). Revision surgery occurred in 22.7%, and in 8.5% for iliac fixation specifically, but with no differences between fixation types (P = 0.55 and P = 0.365). Pelvic fixation failure conferred worse HRQL scores (physical component score [PCS] 36.23 vs. 39.37, P= 0.04; ODI 33.81 vs. 27.93, P = 0.036), and less 2 years improvement (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). Lumbopelvic fixation failure rates were high following ASD correction, and associated with lesser clinical improvements. S2AI screws were more likely to demonstrate loosening, but less commonly associated with rod fractures at the lumbopelvic region.

Global coronal decompensation and adult spinal deformity surgery: comparison of upper-thoracic versus lower-thoracic proximal fixation for long fusions.

Deterioration of global coronal alignment (GCA) may be associated with worse outcomes after adult spinal deformity (ASD) surgery. The impact of fusion length and upper instrumented vertebra (UIV) selection on patients with this complication is unclear. The authors' objective was to compare outcomes between long sacropelvic fusion with upper-thoracic (UT) UIV and those with lower-thoracic (LT) UIV in patients with worsening GCA ≥ 1 cm. This was a retrospective analysis of a prospective multicenter database of consecutive ASD patients. Index operations involved instrumented fusion from sacropelvis to thoracic spine. Global coronal deterioration was defined as worsening GCA ≥ 1 cm from preoperation to 2-year follow-up. Of 875 potentially eligible patients, 560 (64%) had complete 2-year follow-up data, of which 144 (25.7%) demonstrated worse GCA at 2-year postoperative follow-up (35.4% of UT patients vs 64.6% of LT patients). At baseline, UT patients were younger (61.6 ± 9.9 vs 64.5 ± 8.6 years, p = 0.008), a greater percentage of UT patients had osteoporosis (35.3% vs 16.1%, p = 0.009), and UT patients had worse scoliosis (51.9° ± 22.5° vs 32.5° ± 16.3°, p < 0.001). Index operations were comparable, except UT patients had longer fusions (16.4 ± 0.9 vs 9.7 ± 1.2 levels, p < 0.001) and operative duration (8.6 ± 3.2 vs 7.6 ± 3.0 hours, p = 0.023). At 2-year follow-up, global coronal deterioration averaged 2.7 ± 1.4 cm (1.9 to 4.6 cm, p < 0.001), scoliosis improved (39.3° ± 20.8° to 18.0° ± 14.8°, p < 0.001), and sagittal spinopelvic alignment improved significantly in all patients. UT patients maintained smaller positive C7 sagittal vertical axis (2.7 ± 5.7 vs 4.7 ± 5.7 cm, p = 0.014). Postoperative 2-year health-related quality of life (HRQL) significantly improved from baseline for all patients. HRQL comparisons demonstrated that UT patients had worse Scoliosis Research Society-22r (SRS-22r) Activity (3.2 ± 1.0 vs 3.6 ± 0.8, p = 0.040) and SRS-22r Satisfaction (3.9 ± 1.1 vs 4.3 ± 0.8, p = 0.021) scores. Also, fewer UT patients improved by ≥ 1 minimal clinically important difference in numerical rating scale scores for leg pain (41.3% vs 62.7%, p = 0.020). Comparable percentages of UT and LT patients had complications (208 total, including 53 reoperations, 77 major complications, and 78 minor complications), but the percentage of reoperated patients was higher among UT patients (35.3% vs 18.3%, p = 0.023). UT patients had higher reoperation rates of rod fracture (13.7% vs 2.2%, p = 0.006) and pseudarthrosis (7.8% vs 1.1%, p = 0.006) but not proximal junctional kyphosis (9.8% vs 8.6%, p = 0.810). In ASD patients with worse 2-year GCA after long sacropelvic fusion, UT UIV was associated with worse 2-year HRQL compared with LT UIV. This may suggest that residual global coronal malalignment is clinically less tolerated in ASD patients with longer fusion to the proximal thoracic spine. These results may inform operative planning and improve patient counseling.

Reduced occurrence of primary rod fracture after adult spinal deformity surgery with accessory supplemental rods: retrospective analysis of 114 patients with minimum 2-year follow-up.

Rod fracture (RF) after adult spinal deformity (ASD) surgery is reported in approximately 6.8%-33% of patients and is associated with loss of deformity correction and higher reoperation rates. The authors' objective was to determine the effect of accessory supplemental rod (ASR) placement on postoperative occurrence of primary RF after ASD surgery. This retrospective analysis examined patients who underwent ASD surgery between 2014 and 2017 by the senior authors. Inclusion criteria were age > 18 years, ≥ 5 instrumented levels including sacropelvic fixation, and diagnosis of ASD, which was defined as the presence of pelvic tilt ≥ 25°, sagittal vertical axis ≥ 5 cm, thoracic kyphosis ≥ 60°, coronal Cobb angle ≥ 20°, or pelvic incidence to lumbar lordosis mismatch ≥ 10°. The primary focus was patients with a minimum 2-year follow-up. Of 148 patients who otherwise met the inclusion criteria, 114 (77.0%) achieved minimum 2-year follow-up and were included (68.4% were women, mean age 67.9 years, average body mass index 30.4 kg/m2). Sixty-two (54.4%) patients were treated with traditional dual-rod construct (DRC), and 52 (45.6%) were treated with ASR. Overall, the mean number of levels fused was 11.7, 79.8% of patients underwent Smith-Petersen osteotomy (SPO), 19.3% underwent pedicle subtraction osteotomy (PSO), and 66.7% underwent transforaminal lumbar interbody fusion (TLIF). Significantly more patients in the DRC cohort underwent SPO (88.7% of the DRC cohort vs 69.2% of the ASR cohort, p = 0.010) and TLIF (77.4% of the DRC cohort vs 53.8% of the ASR cohort, p = 0.0001). Patients treated with ASR had greater baseline sagittal malalignment (12.0 vs 8.6 cm, p = 0.014) than patients treated with DRC, and more patients in the ASR cohort underwent PSO (40.3% vs 1.6%, p < 0.0001). Among the 114 patients who completed follow-up, postoperative occurrence of RF was reported in 16 (14.0%) patients, with mean ± SD time to RF of 27.5 ± 11.8 months. There was significantly greater occurrence of RF among patients who underwent DRC compared with those who underwent ASR (21.0% vs 5.8%, p = 0.012) at comparable mean follow-up (38.4 vs 34.9 months, p = 0.072). Multivariate analysis demonstrated that ASR had a significant protective effect against RF (OR 0.231, 95% CI 0.051-0.770, p = 0.029). This study demonstrated a statistically significant decrease in the occurrence of RF among ASD patients treated with ASR, despite greater baseline deformity and higher rate of PSO. These findings suggest that ASR placement may provide benefit to patients who undergo ASD surgery.

105. Global coronal decompensation after adult spinal deformity surgery: comparison of upper vs lower thoracic proximal fixation

<h3>BACKGROUND CONTEXT</h3> Deterioration of global coronal alignment (GCA) may be associated with worse outcomes after adult spinal deformity (ASD) surgery. The impact of fusion length and upper instrumented vertebra (UIV) selection for patients with this complication is unclear. <h3>PURPOSE</h3> Our objective was to compare outcomes for long sacropelvic fusions with upper-thoracic (UT) vs lower-thoracic (LT) UIV in patients with worsening GCA≥1cm. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of a prospectively collected multicenter case registry. <h3>PATIENT SAMPLE</h3> Database enrollment required age ≥18 years, scoliosis ≥20°, sagittal vertical axis (SVA) ≥5cm, pelvic tilt ≥25°, or thoracic kyphosis ≥60°. <h3>OUTCOME MEASURES</h3> Radiographic alignment, HRQL (Oswestry Disability Index [ODI], Short Form-36 [SF-36], Scoliosis Research Society-22 [SRS-22r], numerical rating scale [NRS] back/leg pain scores), and complications. <h3>Methods</h3> This is a retrospective analysis of a prospective multicenter database of consecutive ASD patients. Index operations involved instrumented fusion from sacropelvis to thoracic spine. Global coronal deterioration was defined as worsening GCA≥1cm from preoperative to 2-year follow-up. <h3>Results</h3> Of 875 potentially eligible patients, 560 (64%) had complete 2-year follow-up data, of which 144 (25.7%) demonstrated worse GCA at 2-year postop (UT 35.4%, LT 64.6%). At baseline, UT had younger age (61.6±9.9 vs 64.5±8.6years, p=0.008), more osteoporosis (35.3% vs 16.1%, p=0.009), and worse scoliosis (51.9±22.5° vs 32.5±16.3°, p<0.001). Index operations were comparable except UT had longer fusions (16.4±0.9 vs 9.7±1.2 levels, p<0.001) and operative duration (8.6±3.2 vs 7.6±3.0hrs, p=0.023). At 2-year follow-up, global coronal deterioration averaged 2.7±1.4cm (1.9 to 4.6cm, p<0.001), scoliosis improved (39.3±20.8° to 18.0±14.8°, p<0.001), and sagittal spinopelvic alignment improved significantly for all patients. UT maintained smaller positive C7-sagittal vertical axis (SVA) (2.7±5.7 vs 4.7±5.7cm, p=0.014). Postoperative 2-year health-related quality-of-life (HRQL) was significantly improved from baseline for all patients. Significant HRQL comparisons included: UT had worse SRS-22r Activity (3.2±1.0 vs 3.6±0.8, p=0.040) and SRS-22r Satisfaction (3.9±1.1 vs 4.3±0.8, p=0.021). Also, fewer UT patients improved by ≥1 minimal clinically important difference in leg pain NRS (41.3% vs 62.7%, p=0.020). Total reported complications (total=208, reoperation=53/major=77/minor=78) had comparable percentages of affected UT vs LT patients, but the percentage of re-operated patients was higher for UT (35.3% vs 18.3%, p=0.023). UT had higher reoperation rates for rod fracture (13.7% vs 2.2%, p=0.006), pseudarthrosis (7.8% vs 1.1%, p=0.006), but not proximal junctional kyphosis (9.8% vs 8.6%, p=0.810). <h3>Conclusions</h3> In ASD patients with worse 2-year GCA after long sacropelvic fusion, upper-thoracic UIV was associated with worse 2-year HRQL compared to lower-thoracic UIV. This may suggest residual global coronal malalignment is clinically less tolerated in ASD patients with longer fusions to proximal thoracic spine. These results can inform operative planning and improve patient counseling. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P32. Assessing endocrine abnormalities as risk factors for Pseudarthrosis after adult spinal deformity (ASD) surgery at minimum 2 year follow-up

<h3>BACKGROUND CONTEXT</h3> Amongst spine surgeons, pseudarthrosis remains a leading cause of revision surgery. Basic science literature has found endocrine abnormalities to adversely impact bone fusion and healing. Given lack of studies within ASD literature, we evaluated the impact of hypothyroidism and hyperlipidemia on pseudarthrosis, while controlling for potential risk factors. <h3>PURPOSE</h3> We sought to evaluate the association between preoperative hypothyroidism and hyperlipidemia on the development of postoperative pseudarthorsis, in the setting of ASD surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of single-institute database. <h3>PATIENT SAMPLE</h3> A total of 180 ASD patients undergoing spinal fusion of 4 or more levels, between 2008 and 2018. <h3>OUTCOME MEASURES</h3> Development of pseudarthrosis, determined surgically. <h3>METHODS</h3> A retrospective review of a single-institution database. Inclusion criteria was (1) ASD patients 18 and older, (2) undergoing 4 or more levels of arthrodesis with (3) minimum 2-year follow-up. Primary outcome variable was pseudarthrosis which required a reoperation. Primary predictor variable was preoperative diagnosis of hypothyroidism or hyperlipidemia (HLD). Additional variables collected included patient demographics, surgical parameters (levels fused, three column osteotomy, iliac fixation, and revision surgery), and Charlson Comorbidity Index. Multivariable logistic regression analysis was used to determine risk factors for pseudarthrosis, after controlling for patient characteristics (Age, Gender, CCI, smoking status) and surgical characteristics (BMP use). <h3>RESULTS</h3> A total of 180 patients met inclusion criteria, 147 (82%) were women with a mean ± standard deviation of age was 61 ±12 years. Mean levels fused was 9.6 ± 3.8. At a mean follow-up of 4.33 years (Range 2-10 years), 31 (17%) patients developed pseudarthrosis, which required revision surgery. On multivariable logistic regression, risk factors for pseudarthrosis included preoperative hypothyroidism (aOR:3.20, 95% CI: 1.09, 9.39, P=0.03) and HLD (aOR:2.95, 95% CI: 1.08, 8.08, P=0.04). Patient demographics and operative variables were not associated with postoperative pseudarthrosis. <h3>CONCLUSIONS</h3> We found that preoperative diagnosis of hypothyroidism and HLD were independent associated with postoperative pseudarthrosis. This study has direct clinical implications by highlighting the importance of screening for endocrine abnormalities. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

104. Highest achievable outcomes for adult spinal deformity corrective surgery by frailty

<h3>BACKGROUND CONTEXT</h3> Frailty status has often been identified as a determining factor for outcomes after adult spinal deformity (ASD) corrective surgery and may result in a ceiling regarding the best possible outcome <h3>PURPOSE</h3> Identify cohorts of patients with low complication rates by frailty status and determine the duration of time they maintain a good surgical outcome. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study of a prospectively enrolled ASD database. <h3>PATIENT SAMPLE</h3> This study included 224 ASD patients. <h3>OUTCOME MEASURES</h3> Major complications, reoperations, patient-reported outcome measures (Oswestry Disability Index) <h3>Methods</h3> ASD patients with frailty measures, baseline (BL) and 2-year (2Y) ODI were included. Miller et al thresholds: Not Frail (NF) < 0.3; 0.3 < Frail (F) < 0.5; Severely Frail (SF) > 0.5. ANCOVA found estimated marginal means adjusting for age, invasiveness, and BL Sacral Slope, Pelvic Tilt, Pelvic Incidence, PI-LL, and SVA. Kaplan-Meier curve estimated time until major complication or reoperation. Linear regression analyzed ODI change between 1Y and 2Y. Reduction in ODI between 1Y and 2Y of 5+ points was improvement, within ±5 points maintenance, increasing by 5+ points deterioration. Minimum clinically important differences (MCID) for ODI at 2Y were also assessed. <h3>Results</h3> Of 224 patients, 54.9% NF, 29.9% F, and 15.2% SF, difference in ODI from BL to 2Y in the most improved quartile (HIGHEST) by frailty group: NF: -4.51; F: -12.3; SF: -66.3 (p<0.001). SF HIGHEST major complication rate: 58.3%, F HIGHEST 29.4%, NF HIGHEST 41.8%. At 1Y, the quartile of NF with the lowest ODI had a mean score of 2.28, F 8.98, and SF 9.66 (p<0.001). Fewer SF patients did not experience any complications and had 2Y PI-LL < 10 (6.4%) compared to F (11.6%) and NF (16.0%) (p=0.002). NF had the least deterioration (16.3%, F: 29.8%, SF: 30.6%, p=0.099); however, groups were not significantly different in improvement (NF: 37.6%, F: 30.6%, SF: 36.6%, p=0.656). Higher 1Y ODI had greater odds of improvement (1.823 [1.667-1.978], p<0.001). KM curve revealed that NF had longer estimated time before complication or reoperation (7.8 years) compared to F (6.3 years) and SF (3.9 years) (p=0.001). <h3>Conclusions</h3> Severely frail patients had the lowest estimated time before a major complication or reoperation. Frail patients had the best maintenance of ODI score between 1 and 2 years. Severe frailty may limit improvement, and improving to a lower ODI score is more difficult to maintain over the course of a year. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Posterior Polyethylene Tethers Reduce Occurrence of Proximal Junctional Kyphosis After Multilevel Spinal Instrumentation for Adult Spinal Deformity: A Retrospective Analysis.

Proximal junctional kyphosis (PJK) is a common postoperative complication after adult spinal deformity (ASD) surgery and may manifest with neurological decline, worsening spinal deformity, and spinal instability, which warrant reoperation. Rates of PJK may be as high as 69.4% after ASD surgery. To evaluate the efficacy of junctional tethers for PJK prophylaxis after multilevel instrumented surgery for ASD with minimum 2-yr follow-up. Single-center retrospective analysis of adult patients (age ≥18 yr) who underwent ASD surgery with index operations performed between November 2010 and June 2016 and achieved minimum 2-yr follow-up. Patients with ASD were subdivided into 3 treatment cohorts based on institutional protocol: no tether (NT), polyethylene tether-only (TO), and tether with crosslink (TC). PJK was defined as a proximal junctional angle (PJA) >10° and 10° greater than the corresponding preoperative measurement. Patient demographics, operative details, standard radiographic scoliosis measurements (including PJA and assessment of PJK), and complications were analyzed. Of 184 patients, 146 (79.3%) achieved minimum 2-yr follow-up (mean=45 mo; mean age=67 yr; 67.8% women). PJK rates reported for the NT, TO, and TC cohorts were 60.7% (37/61), 35.7% (15/42), and 23.3% (10/43), respectively. PJK rates among TC patients were significantly lower than NT (P=.01601). Junctional tethers with crosslink significantly reduced the incidence of PJK and revisions for PJK among ASD patients treated with long-segment posterior instrumented fusions who achieved minimum 2-yr follow-up.

The Effect of Discharging Patients with Low Hemoglobin Levels on Hospital Readmission and Quality of Life after Adult Spinal Deformity Surgery

Study DesignRetrospective cohort.PurposeThis study aims to evaluate the impact of anemia on functional outcomes, health-related quality of life (HRQoL), and early hospital readmission (EHR) rates after adult spinal deformity (ASD) surgery at the time of discharge from the hospital.Overview of LiteratureConcerns with risks of transfusion, insufficient evidence for its benefits, and the possibility of associated adverse outcomes have led to restrictive transfusion practices. Therefore, patients are discharged according to patient blood management programs that are implemented in hospitals nationwide to reduce unnecessary blood transfusions. However, not many comprehensive kinds of studies exist on the effect of postoperative anemia on functional life and complications.MethodsAnemia severity was defined following the 2011 World Health Organization guidelines. All patients had HRQoL tests as well as complete blood counts pre- and postoperatively. EHR is the admission within 30 days of discharge and was used as the dependent parameter.ResultsThis study comprised 225 surgically treated ASD patients with a median age of 62.0 years, predominantly women (80%). Of the 225 patients, 82, 137, and six had mild, moderate, and severe anemia at the time of discharge, respectively. Seventeen of the patients (mild [11, 64.7%]; moderate [5, 29.4%]; severe [1, 5.9%]) were readmitted within 30 days. The mean hemoglobin values were higher in readmitted patients (p=0.071). Infection was the leading cause of readmission (n=12), but a low hemoglobin level was not observed in any of these patients at the time of discharge. Except for Scoliosis Research Society-22 questionnaire, HRQoL improvements did not reach statistical significance in early readmitted patients in the first year after surgery.ConclusionsThe results of this study demonstrated that the occurrence and the severity of postoperative anemia are not associated with EHR in surgically treated patients with ASD. The findings of the current research suggested that clinical awareness of the parameters other than postoperative anemia may be crucial. Thus, improvements in HRQoL scores were poor in early readmitted patients 1 year after surgery.

Defining a Surgical Invasiveness Threshold for Increased Risk of a Major Complication Following Adult Spinal Deformity Surgery.

Retrospective review. The aim of this study was to define a surgical invasiveness threshold that predicts major complications after adult spinal deformity (ASD) surgery; use this threshold to categorize patients into quartiles by invasiveness; and determine the odds of major complications by quartile. Understanding the relationship between surgical invasiveness and major complications is important for estimating the likelihood of major complications after ASD surgery. Using a multicenter database, we identified 574 ASD patients (more than 5 levels fused; mean age, 60 ± 15 years) with minimum 2-year follow-up. Invasiveness was calculated as the ASD Surgical and Radiographic (ASD-SR) score. Youden index was used to identify the invasiveness score cut-off associated with optimal sensitivity and specificity for predicting major complications. Resulting high- and low-invasiveness groups were divided in half to create quartiles. Odds of developing a major complication were analyzed for each quartile using logistic regression (alpha = 0.05). The ASD-SR cutoff score that maximally predicted major complications was 90 points. ASD-SR quartiles were 0 to 65 (Q1), 66 to 89 (Q2), 90 to 119 (Q3), and ≥120 (Q4). Risk of a major complication was 17% in Q1, 21% in Q2, 35% in Q3, and 33% in Q4 (P < 0.001). Comparisons of adjacent quartiles showed an increase in the odds of a major complication from Q2 to Q3 (odds ratio [OR] 1.8; 95% confidence interval [CI]: 1.0-3.0), but not from Q1 to Q2 or from Q3 to Q4. Patients with ASD-SR scores ≥90 were 1.9 times as likely to have a major complication than patients with scores <90 (OR 1.9, 95% CI 1.3-2.9). Mean ASD-SR scores above and below 90 points were 121 ± 25 and 63 ± 17, respectively. The odds of major complications after ASD surgery are significantly greater when the procedure has an ASD-SR score ≥90. ASD-SR score can be used to counsel patients regarding these increased odds.Level of Evidence: 3.

A clinical study regarding the outcomes of symptomatic spinal epidural haematoma after adult spinal deformity surgery.

Symptomatic spinal epidural haematoma (SSEH) is a rare but serious postoperative complication. This study aimed to assess the prevalence, causes and treatment of SSEH after adult spinal deformity (ASD) surgery. The patients admitted from August 2012 till August 2016 were retrospectively reviewed using case notes. During these four years, 102 patients were admitted with adult spinal deformity, out of which 3 (2.9%) developed post-operative SSEH. The duration between surgery to onset of SSEH was 10-13 hours (average 11.7 hours) post-operatively. Three patients were treated by haematoma evacuation at 8.5-14 hour (average 11.4 hours) after the symptoms appeared. One patient had improved by 2 Frankel grades, and two patients had improved by1 Frankel grade at the last followup. The results concluded that post-operative SSEH occurred in 2.9% of ASD patients who underwent corrective spinal procedures. Improvement in neurological deficits can be achieved by early haematoma evacuation.

275. Opioid use after adult spinal deformity surgery: propensity-matched comparison of Japanese vs amAmerican cohorts

BACKGROUND CONTEXT Amidst a current US opioid epidemic, it is important to understand factors that contribute to long-term or sustained opioid use after elective spine surgery. Recent reports have reported up to 25% of opioid-naive patients are taking opioids at 2-year follow-up after adult spinal deformity (ASD) surgery. This suggests ASD surgery, or at least the postoperative course, could be a significant factor contributing to long-term or sustained opioid use. ln Asian countries, opioids are rarely prescribed for postoperative pain. Potentially, there is a significant cultural difference that can play a role in patient expectations in the postoperative period leading to long-term opioid use. PURPOSE To compare long-term or sustained (2-years) opioid use after ASD surgery between American and Japanese Cohorts STUDY DESIGN/SETTING Propensity-matched comparison of American and Japanese ASD patients PATIENT SAMPLE Patients from two (United States vs Japanese) prospective, multicenter ASD databases were compared OUTCOME MEASURES Baseline and 2-year opioid use and SRS-22 domains were compared METHODS We propensity matched 127 JPN to 619 US ASD patients based on age, sex, BMI, 3-column osteotomy, pelvic fixation, number of levels fused and preoperative SVA. Pre-op and 2-year postoperative opioid use was determined using responses to SRS22R Q11 and grouped into 3 categories (none, weekly, or daily). We have previously validated the use of SRS22R Q11 as an accurate measure for opioid use by comparing to a prospective study specifically designed to study opioid use and postoperative outcomes in ASD. RESULTS From each cohort, 34 cases were successfully matched, with no difference in baseline parameters, including baseline opioid use (p=0.095), between the cohorts. The relatively low numbers in each cohort arise from difficulty matching a lower BMI and lower baseline opioid use in the JPN cohort. At 2-years postop, 22 US (65%) vs 31 JPN (91%) reported no opioid use, 1 US (3%) vs 0 JPN (0%) reported weekly use, and 11 US (32%) vs 3 JPN (9%) reported daily use (p=0.009). There was no difference in 2-year SRS-22 Self-image and Mental Health between the two groups while US patients had better Satisfaction (4.29 vs 3.84, p=0.032) but lower Function scores (3.52 vs 3.90, p=0.029). CONCLUSIONS In propensity-matched ASD cohorts, 35% of US patients were still using opioids 2 years after surgery compared to 9% of JPN patients, with the most taking opioids daily. Further studies are needed to identify sources of this variability. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Relationship of the character of rod fractures on outcomes following long thoracolumbar fusion to the sacrum for adult spinal deformity

BACKGROUND CONTEXTRod fractures (RF) and pseudarthrosis are a frequent occurrence after adult spinal deformity (ASD) surgery and may be problematic. However, not all RF signal nonunion and cause clinical concern. An improved understanding of the sequelae after RF occurrence is valuable for further management. PURPOSETo characterize the radiographic findings, clinical outcomes, and revision rates between patients who developed unilateral RF (URF) and bilateral RF (BRF) following thoracolumbar posterior spinal fusions to the sacrum for ASD and identify patient characteristics associated with clinically significant RF that lead to subsequent revision surgeries and detection of nonunion. STUDY DESIGN/SETTINGA retrospective single-center cohort study was performed. PATIENT SAMPLEPatients undergoing long-construct posterior spinal fusions to the sacrum performed at a single institution from 2004 to 2014 and developed a RF postoperatively were included. OUTCOME MEASURESPatient demographics, radiographic parameters, surgical data, Oswestry Disability Index (ODI), Scoliosis Research Society-22 (SRS-22), and revision rates. METHODSInclusion criteria were ASD patients age >18 who had ≥5 vertebrae instrumented and fused posteriorly to the sacrum and development of RF. Data were compared among patients: who developed unilateral-nondisplaced RF (UNRF), unilateral-displaced RF (UDRF), bilateral-nondisplaced RF and bilateral-displaced RF (BDRF) at baseline and follow-up. ODI and SRS-22 scores were assessed at baseline, 1 year postoperatively, the time of RF occurrence, and latest follow-up. RESULTSOf 526 patients who met inclusion criteria, 96 (18.3%) developed RF (URF n=70 [73%]; BRF n=26 [27%]). Preoperative demographics and surgical parameters were similar between the groups. BRF patients had substantial loss of sagittal correction from 1-year postoperatively to the time of RF, including loss of sagittal vertical axis (4.8 cm vs. 2.2 cm; p<.001), loss of lumbar lordosis (14.8° vs. 4.9°; p=.010) and loss of pelvic incidence minus lumbar lordosis mismatch (PI-LL) mismatch (5.0° vs. 14.6°; p=.020) compared with those of URF patients. The BDRF group had more loss of ODI scores (13.4 vs. 4.2; p=.013), SRS pain score (0.8 vs. 0.2; p=.024), SRS function score (0.3 vs. 0; p=.020) and SRS subscore (0.4 vs. 0.1; p=.148) from 1-year postoperatively to the time of RF and underwent revision surgery more often than the UNRF group (87.5% vs. 4.8%; p<.0001). At final follow-up (median 2.8 years, range 1–10.3 years after RF detection), URF patients who did not undergo revision surgeries still maintained equivalent sagittal alignment correction (sagittal vertical axis, LL and PI-LL; all p>.05) and had similar, not worse, mean ODI scores, SRS Subscore and SRS pain compared with the time at RF and 1-year follow-up. CONCLUSIONSRF are not uncommon after ASD operations. Asymptomatic, UNRF in our study did not jeopardize clinical outcomes or radiographic alignment parameters and, in most cases, did not represent a nonunion, as opposed to BRF. BRF patients exhibited loss of sagittal correction, loss of clinical outcome improvements, as measured by ODI, SRS pain and SRS Subscore at the time of RF, and were revised more often than URF patients.