Faculty Bibliography

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: Numerous strategies are used to minimize PJK in (ASD). The use of PPS is one such strategy. Studying this topic is difficult as there is a lack of homogeneity in the patient population being studied. PURPOSE: Investigate if PPS minimizes the risk of perioperative PJK compared to traditional open techniques. STUDY DESIGN/SETTING: Retrospective review of prospective multicenter adult spinal deformity database PATIENT SAMPLE: Inclusion criteria are age >18, and one of the following: PT>25, PI-LL>10, or SVA>5 cm. OUTCOME MEASURES: NRS leg, ODI, SF-12, EQ5D, SRS-22.
METHOD(S): A prospective database was retrospectively reviewed. Inclusion criteria are age >18, and one of the following: PT>25, PI-LL>10, or SVA>5 cm. Patients were grouped as MIS (all PPS no open component) or OPEN. Propensity matching was used to create 2 equal groups controlling for: age, BMI, Preop (PI-LL, PI, TPA), and post op (PI-LL correction and posterior levels fused). PJK was evaluated in 2 groups: Mild (PJK10) 10degree change from preop and severe (PJK20) a 20degree change, as previously reported.
RESULT(S): A total of 1,023 patients met criteria: 114 MIS and 909 OPEN. MIS were older with higher BMI. No significant difference was found between groups in preop alignment or SRS Schwab classification. OPEN had more levels fused (11.3 vs 5.5), change in PI-LL (14.9 vs 9.3) and LL (16.2 vs 9.7; all p<0.01). After matching: 77 patients in each group with no difference in demographics or levels fused (6.26 +/- 3.7 OPEN; 6.23 +/- 3.4 MIS). At 1YR NRS leg, ODI, SF-12, EQ5D, SRS-22 were equal. MIS had improved NSR Back compared to OPEN (2.6 vs 3.4; p=0.047). Alignment (PI-LL, TPA, SVA, LL, PT, PI) showed no difference preop, 6 weeks or at 1YR. PJK10 was 23.9% OPEN v 20.3% in MIS at 6 weeks and 28.6% and 19.5% at 1 YR (p>0.59). PJK20 was 2.6% in OPEN vs 3.9% in MIS at 1YR (p=1). The PJK angle was not different (4.3 v 4.2). MIS had less EBL (510 v 1574 cc; p=0.000) longer OR time (448 v 373 min; p=0.022) and more interbodies (3.4 vs 2.1; p=0.000). There was no difference in rate of revision surgery (14.3% OPEN vs 10.4%). Major complications occurred more frequently in OPEN (23.4% vs 9.1%).
CONCLUSION(S): While the use of percutaneous fixation intuitively seems protective for PJK, our study found that when controlling for radiographic deformity, deformity correction, demographics and the magnitude of surgical intervention that percutaneous fixation is equivalent to open techniques in rate of perioperative PJK. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Hospital acquired conditions (HACs) were established in the Affordable Care Act, and are defined as reasonably preventable complications that are nonreimbursable. In high risk patient populations for HACs, such as frail surgical spine patients, preoperative evaluation should consider modifiable factors. PURPOSE: To identify if optimizing the modifiable factors in the frailty index reduce the risk of developing HACs in population of surgical spine patients. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: This study included 196,523 elective spine surgery patients in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). OUTCOME MEASURES: Modifiable patient frailty factors: hypertension and diabetes mellitus; rates of HACs, superficial or deep surgical site infection (SSI), deep venous thromboembolism (VTE) and urinary tract infection (UTI), across frailty scores.
METHOD(S): Patients >18 years who underwent elective spine surgery were identified in ACS-NSQIP database from 2005-2016. HACs identified: SSI, VTE, and UTI. Patient frailty was assessed utilizing the modified NSQIP 5-factor frailty index. The modified frailty score (mFI-5) is assessed on a scale between 0 and 1 (no frailty [NF] <0.3, mild frailty [MF] 0.3-0.5, severe frailty [SF] >0.5). Descriptive analysis quantified rates of patient characteristics, operative details, and HAC prevalence. Stepwise linear regression models determined significant predictors of baseline frailty using controllable patient factors. HACs were compared between 'optimized' and 'non-optimized' frailty status in the cohort. Level of significance was set to P<0.05.
RESULT(S): A total of 196,523 patients (57+/-14.2 years, 30.4 kg/m², 48%F) met inclusion criteria. Overall, 5,720 (2.9%) of patients developed an HAC, the most common was an SSI (1.3%), followed by UTI (1.1%). When stratified by the mFI-5 frailty severity groups at baseline, 83.6% of patients were categorized NF, 15.1% MF and 1.3% SF. Within the frailty severity groups, prevalence of overall HACs increased significantly (NF: 2.64%, MF: 4.17%, 5.93%, p<0.001). Rates of all individual postoperative HACs assessed also increased with greater baseline frailty severity: SSI (NF: 1.14%, MF: 1.93%, SF: 2.39%, p<0.001), UTI (NF: 0.91%, MF: 1.66%, SF: 2.85%, p<0.001), VTE (NF: 0.68%, MF: 0.80%, SF: 1.16%, p=0.002). Stepwise linear regression models determined that diabetes mellitus (beta = 0.493) and hypertension (beta = 0.679) were the most significant predictors for increased baseline frailty by way of the mFI-5 NSQIP index (Final model: R2= 0.897). Of total patients, 47.2% had the optimal modifiable frailty factors (no history of diabetes or hypertension). The optimal frailty patients had significantly less overall incidence of SSI (2.03% vs 2.5%, p<0.001), UTI (0.65% vs 1.4%, p<0.001), DVT (0.56% vs 0.84%, p<0.001), and any overall HAC (2.18% vs 3.56%, p<0.001).
CONCLUSION(S): Stepwise linear regression models determined that hypertension and diabetes account for 89.7% of variance in baseline mFI-5 score. Patients with these optimal controllable factors had reduced incidence of all hospital acquired conditions. In order to optimize hospital resources and treatment outcomes, physicians and patients should be aware of the modifiable factors that contribute to a patient's frailty that can ultimately impact acquiring HACs. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Revision surgery is often necessary for adult spinal deformity (ASD) patients. Satisfaction with management is an important component of HRQOL. PURPOSE: We hypothesized that patients who underwent multiple revision surgeries following adult spinal deformity correction would exhibit lower satisfaction scores. STUDY DESIGN/SETTING: Retrospective cohort study of a prospectively collected multicenter database of ASD patients. PATIENT SAMPLE: A total of 668 patients undergoing ASD surgery and eligible for minimum 2-year follow-up were included. OUTCOME MEASURES: SRS-22r satisfaction score.
METHOD(S): Visits were stratified by occurrence prior to the index surgery (period 0), after the index surgery only (period 1) (ie, never underwent revision or had not yet undergone revision), after first revision only (period 2), and after second revision only (period 3). Patients were further stratified by prior spine surgery before their index surgery. SRS-22r satisfaction scores were evaluated at all periods using multiple linear regression adjusting for age, gender, and CCI.
RESULT(S): In total, 46.6% had prior spine surgery before their index surgery. The overall revision rate was 21.3%. among patients with no spine surgery prior to the index surgery, satisfaction increased from period 0 to 1 (2.8 to 4.3, p<0.0001), decreased after one revision from period 1 to 2 (4.3 to 3.9, p=0.0004), and decreased after a second revision from period 2 to 3 (3.9 to 3.3, p=0.0437). Among patients with spine surgery prior to the index procedure, satisfaction increased from period 0 to 1 (2.8 to 4.2, p<0.0001), and decreased from period 1 to 2 (4.2 to 3.8, p=0.0011). No differences in follow-up time from last surgery were observed between visits in periods 1, 2, and 3 (all p>0.3). among patients with multiple revisions, 40% experienced rod fracture, 40% PJK, and 33% pseudarthrosis.
CONCLUSION(S): ASD patients exhibit decreased satisfaction with subsequent revision. Among patients undergoing primary surgery in our database, this effect is additive for multiple revisions. These results have important implications for surgeons, patients, insurers, hospital administrators, and policymakers. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Prior studies have demonstrated potential benefits of adult spinal deformity (ASD) surgery, but less outcomes data exist for operative ASD patients with severe scoliotic curves (thoracic [TH] curve >=75degree, thoracolumbar [TL] curve >=50degree, or lumbar [LL] curve >=50degree). Also, the surgical complication profile is less clear for this subset of patients with severe scoliotic deformity and warrants focused investigation. PURPOSE: The objective of the current study was to assess treatment outcomes and complication rates associated with ASD surgery in patients with severe scoliosis. STUDY DESIGN/SETTING: Retrospective review of a prospectively collected multicenter consecutive case registry PATIENT SAMPLE: Enrollment required: age >=18 yrs, scoliosis >=20degree, sagittal vertical axis (SVA) >=5cm, pelvic tilt >=25degree, and/or thoracic kyphosis >=60degree. OUTCOME MEASURES: 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, and Scoliosis Research Society-22 (SRS-22) scores.
METHOD(S): Using a prospective multicenter database, we identified surgically treated ASD patients with severe scoliosis (TH Cobb >=75degree or TL/LL Cobb >=50degree) and minimum 2-yr follow-up. Demographic data, surgical characteristics, radiographic alignment measurements, HRQL outcomes and associated complications were analyzed.
RESULT(S): Of 178 patients, 146 (82%, mean age 54 yrs, 92% women, 88 TL, 50 LL, 8 TH) had minimum 2-yr follow-up (mean=3.1 yrs). Almost 30% had prior spine fusion, 6% were active or past smokers, 16% had osteoporosis and 77% had at least 1 comorbidity. Surgical details included: posterior-only (58%) or anterior-posterior approach (42%), SPO (65%), 3CO (14%), TLIF (23%), ALIF (37%), sacropelvic fixation (76%), upper thoracic UIV (64%) and mean posterior fusion length of 13.2 levels. Postoperative coronal alignment improved significantly for all patients (global coronal alignment 3.8 to 2.8 cm, p< 0.001; TH Cobb 38degree to 24degree, p<0.001; TL Cobb 61degree to 30degree, p<0.001; LL Cobb 50degree to 24degree, p<0.001; Fractional Cobb 20degree to 7degree, p<0.001). Overall sagittal alignment also improved significantly (p<0.05), most notably for severe lumbar curves (C7-S1 SVA 6.7 to 2.5 cm, p<0.001; PI-LL 18degreeto 3degree, p<0.001). Overall HRQL improved significantly, including ODI (39 to 26, p<0.001), SF-36 PCS (35 to 41, p<0.001) and SRS-22r (2.9 to 3.8, p<0.001). A total of 191 complications were reported (92 minor/99 major), and 94 (64%) patients had at least one complication. The most common complications included dural tear (12%), pleural effusion (12%), rod fracture (11%), radiculopathy (8%) and proximal junctional kyphosis (7%). 34 reoperations were performed in 27 (18%) patients, with most common indications of rod fracture/pseudarthrosis (8), deep wound infection (6) and neurological deficit (5).
CONCLUSION(S): Surgery for severe adult scoliosis is associated with significant improvement in radiographic alignment and HRQL measures. Although associated complication rates are high, these appear to be comparable to reports of less severe scoliosis. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Traditionally, adult spinal deformity (ASD) has been treated with long segment fusions with the goal of restoring sagittal and coronal alignment. Long segment fusions can be associated with high rates of complications and morbidity. Some patients are reluctant to undergo large procedures. Others have comorbidities excluding them as good surgical candidates for long fusions. PURPOSE: To compare baseline and postoperative HRQL and radiographic outcomes and revisions and complications in small vs longer fusions for ASD. STUDY DESIGN/SETTING: Retrospective analysis of a prospective, multicenter database PATIENT SAMPLE: Surgical ASD patients OUTCOME MEASURES: ODI, SF36-PCS, SRS22, NRS back and leg pain.
METHOD(S): A prospective database of operative ASD patients who completed two year follow up was analyzed. Prior thoracolumbar fusions were excluded. Patients were divided into short fusions (SF: 3 levels) and long fusions (LF: 36 levels). LF and SF patients were compared in baseline alignment. Propensity matching (PSM) controlling for baseline alignment (TPA and maximum coronal cobb) was performed to compare SF and LF in HRQL improvement, postop alignment and complications. Subanalysis of SF identified which patients were more likely to have successful surgery. The level of significance was p<0.05.
RESULT(S): A total of 298 patients met inclusion criteria (SF n=20, mean levels fused 2.13; LF n=275, mean fusion levels 12.33). Prior to PSM, LF had greater PT, coronal cobb, and TPA. Following PSM, LF had better improvements in PILL (20.8 vs 3.37), PT (8.57 vs 0.21), TPA (8.68 vs 2.07), and coronal cobb (17.3 vs 5.33) all p<0.005. There were no differences in 2y HROL improvement, satisfaction or reoperations. SF had fewer complications (OR 0.15, p=0.018). In the SF group, the deformities were 15% sagittal, 40% coronal, and 45% combined. In the sagittal group, 67% of surgery aimed at deformity correction but 67% of these required revision long fusion surgery. In the coronal group, 38% of surgery aimed at deformity correction with no revisions. In the combined group. 67% of surgery aimed at deformity correction but 11% of these required revision long fusion surgery.
CONCLUSION(S): This study shows that a more limited fusion could be an alternative to the more traditional long segment fusion in carefully selected patients with adult spinal deformity since there were fewer complications but similar short-term (2-year) satisfaction rates and HRQL improvements. Patients undergoing long fusions had better improvements in alignment. The majority of sagittal only deformities undergoing short fusions required revision surgery. The durability of short fusions in the setting of ASD needs to be investigated with long term studies. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Neurologic complications following adult spinal deformity (ASD) are common and may play a role in the outcomes for our patients. Neurologic complications may include radiculopathy, sensory deficit or motor weakness. The impact that these specific complications have on HRQL is unknown. PURPOSE: Neurologic complications are common following ASD. Understanding their impact on Health-related quality of life (HRQL) measures is critical. STUDY DESIGN/SETTING: Retrospective cohort study of prospective ASD database. PATIENT SAMPLE: Retrospective cohort study, 733 patients. OUTCOME MEASURES: Neurologic complications, HRQL scores.
METHOD(S): ASD patients (>18yrs, scoliosis >=20degree, SVA >=5cm, PT >=25degree and/or TK >60degree). Inclusion criteria was HRQL at baseline (BL) and 1 year, and lower extremity motor score (LEMS) at BL, 6-week and 1-year ODI, SRS22r and SF36 were determined at BL and 1yr LEMS was calculated from 0-50, with 50 designated as normal motor function. Patients were divided into 4 groups: pLEMS (perfect, no deficit), dLEMS (new postop deficit that returned to normal at 1 year), iLEMS (deficit improved from abnormal baseline), and wLEMS (new postop deficit persistent at one year).
RESULT(S): A total of 733 patients were eligible, with 95 (12.96%) reporting neurologic complications (NC). Impact of any NC vs no complication at 1yr was significant for ODI (5.1), PCS (3.6) and SRSpain (0.2) at 1 year (p<0.001 all). For NC vs any other complication, there was still a decrease in ODI (3.9) and PCS (2.4) at 1 year (p<0.01). NC subtype: radiculopathy caused worse outcomes for (4.3) and SRS pain (0.3) (p<0.05), sensory deficit caused worse SRSmental (0.5) (p<0.05), but no HRQL change was detected for motor deficit at 1 year. PLEMS (456/733) had improvement in all HRQL, and these improvements were not different with or w/o NC, or non-NC. Compared to pLEMS w/o complication, dLEMS (62/733) and iLEMS (147/733) were statically similar, however wLEMS (68/733) had worse ODI (7.1), SRStotal (0.3), activity (0.3), mental (0.3), pain (0.3) (p<0.05 all).
CONCLUSION(S): Neurologic complications that occur following ASD have a significant effect on HRQLs. The magnitude of effect is driven by radiculopathy and by lower extremity motor score. LEMS scores that remain normal, return back to normal or improve have similar outcomes, while patients that have continued weakness remain statistically worse at 1 year. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: While advances have been made in the surgical management of distal junctional kyphosis (DJK), complication rates remain high. Although individual factors related to its occurrence have been cited, many of these cases are mild and have no clinical relevance nor have these been combined into a formal predictive model, particularly for cases that are clinically impactful. PURPOSE: Develop a formal predictive model distinguishing between symptomatic and asymptomatic DJK. STUDY DESIGN/SETTING: Retrospective review PATIENT SAMPLE: A total of 99 cervical deformity patients (CD) with 1 year (1Y) follow up OUTCOME MEASURES: Complications; reoperations; HRQL, alignment METHODS: CD patients (pts) were stratified into asymptomatic (Asym) and symptomatic (Sym) DJK. DJK angle (DJKA) was defined >10degree change in kyphosis between LIV and LIV-2 and a >10degree index angle. Asym: DJK to be>10degree in the absence neurologic sequelae. Sym: 1) DJKA> 10degree and either reop due to DJK or >one new-onset neurological sequelae related to DJK or 2) pts who had either a DJKA > 20degree or DJKA > 20degree. Stepwise logistic regressions were used to identify patient-specific, surgical, radiographic and HRQL factors that were associated with these types of DJK. Decision tree analysis established cut-offs for the continuous variables.
RESULT(S): A total of 99 CD pts were included (60yrs, 26.5kg/m2, 66.7%F). Surgical characteristics: 7.4+/-4 levels fused, 47.5% posterior, 18.2% anterior, and 34.3% combined. Overall, 32.2% developed DJK (34.3% Asym, 65.7% Sym). 37.5% of Asym pts received a reop vs 62.5% Sym pts. At BL, Asym pts had a greater BMI (28.5 vs 23kg/m2) and NSR back pain (5.2 vs 4.6; all p<0.05). Decision tree analysis identified osteoporosis, UIV level, and the apex of the region of the spine where the primary deformity is located to predict Sym pts. Top factors predicting Sym pts over Asym were BL EQ5D>0.65, UIV cephalad to C2, and C2-C7 apex caudal to C5. Multivariate analysis identified independent radiographic and surgical factors for developing Sym DJK: [Radiographic] BL PI (1.02[0.9-1.07]), preop cervical flexibility (1.04[1.01-1.07]); [Surgical] combined approach (6.2[1.4-27]; all p<0.05). Having abnormal hyper kyphosis in the thoracic spine, more so than abnormal cervical lordosis, was an independent factor for developing Sym when analyzed against Asym pts (1.2[0.01-115]). Predictive modeling identified factors that were predictive of Sym against no DJK pts such as having myelopathy (mJOA score:12-14), combined approach, UIV=C3 or C4, preoperative hypermobility, and >7 levels fused (AUC: 0.89). A predictive model for Sym versus Asym pts yielded an AUC of 85% and included being frail, having a TS-CL>20, and a PI>46.3. Controlling for BL deformity and disability, Sym pts had greater cSVA(4-8cm: 47.6%vs 27%) and were more maligned according to their SRS-SVA (0.1[0.76-0.02]) than non DJK pts at 1Y (all p<0.05). Despite their symptomatology and higher re-operation rate, outcomes equilibrated in the Sym cohort at 1Y following revision.
CONCLUSION(S): Overall 32.2% cervical deformed patients suffered from DJK most of which were clinically significant. Severe symptomatic DJK can be predicted with high reliability using combined determinants of baseline spinal cord dysfunction, mobility, frailty, and surgical factors including end levels, number of levels fused and use of a combined approach. It can be further distinguished from asymptomatic occurrences by taking into account pelvic incidence and baseline cervicothoracic deformity severity. 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 is an active area of research. Complex corrective measures taken are in ASD. Incidence of specific alignment outcomes has yet to be investigated in each of the complex realignment ideals. PURPOSE: Assess alignment outcomes (pelvic nonresponse [PNR], PJK, postop cervical deformity [CD]) following ASD-corrective surgery in the context of correction relative to various alignment schemas. STUDY DESIGN/SETTING: Retrospective cohort study of prospective ASD database. PATIENT SAMPLE: A total of 468 ASD patients. OUTCOME MEASURES: PNR, PJK, postop CD.
METHOD(S): ASD patients with preop, 6-week postop (6W), and 2-year postop (2Y) radiographic data included. PNR: 10-year mismatch (undercorrection; unimproved) from a patient's age-adjusted PT at 6W and maintained at 2Y. Pelvic responder (PR): PT +/-10 match age-adjusted goals. Patients were stratified by incremental additions of corrective alignment schemas: (a) improvement in Schwab SVA, (b) matching age-adjusted PI-LL, (c) match postop "ideal" and "theoretical" Roussouly, (d) improvement in proportionality spinal score at 6W. PNR, PJK, and CD development by 2Y were compared within groups, as well as simultaneous improvement/match of the suggested corrective measures (exclusively). In a subanalysis, patients were stratified by severity of baseline PT, low (<20degree), moderate (20-30degree), and severe (>30degree) to determine which alignment schema is necessary to achieve less PNR, PJK and postop CD.
RESULT(S): A total of 468 patients (56.3 yrs, 76.5% F; 25.6% PNR, 40.6% PR) met inclusion criteria. Rates of postop PJK (PNR:49.2% vs PR:59.5%) and CD (18.3% vs 25.8%) were significantly less in the PNR group, p<0.05. Sole improvement in Schwab SVA (73.2%) did not impact PNR, PJK or CD (p>0.050). Undercorrected age-adjusted PI-LL presented with more PNR (60.1%), whereas overcorrected had increased PJK (68.2%), p<0.001. Matching Roussouly at 6W decreased PNR (17.8% vs mismatch:42.3%, p=0.002). 6W proportional spine, had lower rates of PNR (19.7%, severely disproportioned: 58.8%, p<0.001), with postop moderately disproportioned GAP with highest rates of PJK (p=0.010). Incremental addition of alignment schemas was assessed for effect on malalignment outcomes. Schwab and age-adjusted use (20.9%) had less incidence of PNR (28.6% vs 38.7%) than just Schwab. Addition of the Roussouly (18.3%) presented with less PNR (20% vs 30.4%) and PJK (38.5% vs 60.3%) than only Schwab & age-adjusted. Lastly, addition of proportion (16.7%) had 0% occurrence of PNR and CD. Stratifying by baseline PT severity, the low group demonstrated the least incidence of PNR (7.7%) and CD (10.3%) and PJK (41.3%) when matching theoretical Roussouly at 6W (all p<0.050). This remained the same for moderate PT for PNR and PJK, except Schwab improvement decreased postop CD occurrence (21.2%, p=0.049). Severe PT assessment determined PNR (20%), PJK (37.5%) and CD (19.4%) were the lowest with improvement of proportion at 6W (p<0.050).
CONCLUSION(S): Following ASD corrective surgery, 25.6% of patients showed residual pelvic malalignment, qualifying as pelvic nonresponders. Use of complex realignment schemas (SRS-Schwab, age-adjusted, Roussouly shape, GAP) decreased rates of pelvic nonresponse, PJK and postop cervical deformity development. Severe (>30degree) baseline pelvic tilt requires particular emphasis of proportionality in addition to other realignment ideals. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Distal junctional kyphosis (DJK) is a radiographic finding identified after patients undergo instrumented spinal fusions which can lead to decreased mobility in the affected spinal segments. There is a lack of consensus of the true etiology of DJK, since it is multifactorial in nature. PURPOSE: Develop a novel risk index specific to each patient to minimize postoperative DJK occurrence using distal construct and surgical factors STUDY DESIGN/SETTING: Retrospective review of a single-center comprehensive CD database PATIENT SAMPLE: A total of 110 CD patients (pts) OUTCOME MEASURES: DJK, Health Related Quality of Life, Reoperation, Minimal Clinically Important Difference (MCID) EQ5D.
METHOD(S): CD pts with BL and at least 1Y radiographic parameters were included. A patient-specific DJK score was created through use of unstandardized Beta weights of a multivariate regression model predicting DJK (end of fusion construct to the 2nd distal vertebra change in this angle by <-10degree from BL to postop). The equation consisted of distal construct factors [A) BL-3M inclination angle, B) BL inflection point, C) LIV angle,] and surgical factors [D) combined approach, E) TS-CL, F) PT, G) C2-C7, H) T4-T12, I) osteoporosis]. A BL model was created as a reference that included all of the above factors not including (C2-C7 and T4-T12). Correlations with 2Y outcomes was identified with use of this BL reference score.
RESULT(S): A total of 110 CD pts included (61yrs, 66.4%F, 28.8kg/m2). Of these, 31.8% pts developed DJK (16.1% 3M, 11.4% 6M, 62.9% 1Y). At BL DJK pts were more frail, had more combined approaches, and had more anterior approaches (all p<0.05). Multivariate model regression analysis identified individualized scores through creation of a DJK equation: 1.15+ 0.04 (Inclination) -2.3 (Preinflection) + 0.04 (LIV angle) + 0.78 (combine approach) + 0.09 (TS-CL) + 0.02 (PT) + 0.11 (C2-C7) + 0.02 (T4-T12) + 0.12 (osteoporosis). This equation (min: 0007 and a max: 95.3) has an 86.3% accuracy of predicting DJK. Having a score>81 predicted DJK with an accuracy of 89.3%. The BL reference equation, (-1.3+0.002 [BL inclination score]-1.3 [BL inclination C6 to T1]-0.05 [BL LIV angle] +1.4 [combined approach] + 0.01 [BL PT]-0.023 [osteoporosis]), correlated with 2Y outcomes of NSR-back percentage(p=0.003), reoperation(p=0.04) and MCID for EQ5D(p=0.04).
CONCLUSION(S): This study created a newly proposed risk index that focuses heavily on distal construct and surgical factors. Having a DJK score >81 was associated with an increase in risk of DJK. The reference models created were identified to correlate with 2-year outcomes of NSR-back percentage, reoperation rates and minimal clinically importance difference for EQ5D. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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