Highest Achievable Outcomes for Adult Spinal Deformity Corrective Surgery: Does Frailty Severity Exert a Ceiling Effect?

STUDY DESIGN: Retrospective single-center study. OBJECTIVE: To assess the influence of frailty on optimal outcome following ASD corrective surgery. SUMMARY OF BACKGROUND DATA: Frailty is a determining factor in outcomes after ASD surgery and may exert a ceiling effect on the best possible outcome. METHODS: ASD patients with frailty measures, baseline, and 2-year ODI included. Frailty was classified as Not Frail (NF), Frail (F) and Severely Frail (SF) based on the modified Frailty Index, then stratified into quartiles based on two-year ODI improvement (most improved designated "Highest"). Logistic regression analyzed relationships between frailty and ODI score and improvement, maintenance, or deterioration. A Kaplan-Meier survival curve was used to analyze differences in time to complication or reoperation. RESULTS: A total of 393 ASD patients were isolated (55.2% NF, 31.0% F, and 13.7% SF), then classified as 12.5% NF-Highest, 17.8% F-Highest, and 3.1% SF-Highest. The SF group had the highest rate of deterioration (16.7%, P =0.025) in the second postoperative year, but the groups were similar in improvement (NF: 10.1%, F: 11.5%, SF: 9.3%, P =0.886). Improvement of SF patients was greatest at six months (ΔODI of -22.6±18.0, P <0.001), but NF and F patients reached maximal ODI at 2 years (ΔODI of -15.7±17.9 and -20.5±18.4, respectively). SF patients initially showed the greatest improvement in ODI (NF: -4.8±19.0, F: -12.4±19.3, SF: -22.6±18.0 at six months, P <0.001). A Kaplan-Meier survival curve showed a trend of less time to major complication or reoperation by 2 years with increasing frailty (NF: 7.5±0.381 yr, F: 6.7±0.511 yr, SF: 5.8±0.757 yr; P =0.113). CONCLUSIONS: Increasing frailty had a negative effect on maximal improvement, where severely frail patients exhibited a parabolic effect with greater initial improvement due to higher baseline disability, but reached a ceiling effect with less overall maximal improvement. Severe frailty may exert a ceiling effect on improvement and impair maintenance of improvement following surgery. LEVEL OF EVIDENCE: Level III.

Factors Influencing Maintenance of Alignment and Functional Improvement Following Adult Spinal Deformity Surgery: A 3-Year Outcome Analysis.

STUDY DESIGN: This was a retrospective review. OBJECTIVE: To assess the factors contributing to durability of surgical results following adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND: Factors contributing to the long-term sustainability of ASD correction are currently undefined. MATERIALS AND METHODS: Operative ASD patients with preoperatively (baseline) and 3-year postoperatively radiographic/health-related quality of life data were included. At 1 and 3 years postoperatively, a favorable outcome was defined as meeting at least three of four criteria: (1) no proximal junctional failure or mechanical failure with reoperation, (2) best clinical outcome (BCO) for Scoliosis Research Society (SRS) (≥4.5) or Oswestry Disability Index (ODI) (<15), (3) improving in at least one SRS-Schwab modifier, and (4) not worsening in any SRS-Schwab modifier. A robust surgical result was defined as having a favorable outcome at both 1 and 3 years. Predictors of robust outcomes were identified using multivariable regression analysis with conditional inference tree for continuous variables. RESULTS: We included 157 ASD patients in this analysis. At 1 year postoperatively, 62 patients (39.5%) met the BCO definition for ODI and 33 (21.0%) met the BCO for SRS. At 3 years, 58 patients (36.9%) had BCO for ODI and 29 (18.5%) for SRS. Ninety-five patients (60.5%) were identified as having a favorable outcome at 1 year postoperatively. At 3 years, 85 patients (54.1%) had a favorable outcome. Seventy-eight patients (49.7%) met criteria for a durable surgical result. Multivariable adjusted analysis identified the following independent predictors of surgical durability: surgical invasiveness >65, being fused to S1/pelvis, baseline to 6-week pelvic incidence and lumbar lordosis difference >13.9°, and having a proportional Global Alignment and Proportion score at 6 weeks. CONCLUSIONS: Nearly 50% of the ASD cohort demonstrated good surgical durability, with favorable radiographic alignment and functional status maintained up to 3 years. Surgical durability was more likely in patients whose reconstruction was fused to the pelvis and addressed lumbopelvic mismatch with adequate surgical invasiveness to achieve full alignment correction.

Risk of spinal surgery among individuals who have been re-vascularized for coronary artery disease.

HYPOTHESIS: Revascularization is a more effective intervention to reduce future postop complications. METHODS: Patients undergoing elective spine fusion surgery were isolated in the PearlDiver database. Patients were stratified by having previous history of vascular stenting (Stent), coronary artery bypass graft (CABG), and no previous heart procedure (No-HP). Means comparison tests (chi-squared and independent samples t-tests, as appropriate) compared differences in demographics, diagnoses, and comorbidities. Binary logistic regression assessed the odds of 30-day and 90-day postoperative (postop) complications associated with each heart procedure (Odds Ratio [95 % confidence interval]). Statistical significance was set p < 0.05. RESULTS: 731,173 elective spine fusion patients included. Overall, 8,401 pts underwent a CABG, 24,037 pts Stent, and 698,735 had No-HP prior to spine fusion surgery. Compared to Stent and No-HP patients, CABG patients had higher rates of morbid obesity, chronic kidney disease, and diabetes (p < 0.001 for all). Meanwhile, stent patients had higher rates of PVD, hypertension, and hyperlipidemia (all p < 0.001). 30-days post-op, CABG patients had significantly higher complication rates including pneumonia, CVA, MI, sepsis, and death compared to No-HP (all p < 0.001). Stent patients vs. No-HF had higher 30-day post-op complication rates including pneumonia, CVA, MI, sepsis, and death. Furthermore, adjusting for age, comorbidities, and sex Stent was significantly predictive of a MI 30-days post-op (OR: 1.90 [1.53-2.34], P < 0.001). Additionally, controlling for levels fused, stent patients compared to CABG patients had 1.99x greater odds of a MI within 30-days (OR: 1.99 [1.26-3.31], p = 0.005) and 2.02x odds within 90-days postop (OR: 2.2 [1.53-2.71, p < 0.001). CONCLUSION: With regards to spine surgery, coronary artery bypass graft remains the gold standard for risk reduction. Stenting does not appear to minimize risk of experiencing a post-procedure cardiac event as dramatically as CABG.

Trends in usage of navigation and robotic assistance in elective spine surgeries: a study of 105,212 cases from 2007 to 2015.

OBJECTIVE: Identify trends of navigation and robotic-assisted elective spine surgeries. METHODS: Elective spine surgery patients between 2007 and 2015 in the Nationwide Inpatient Sample (NIS) were isolated by ICD-9 codes for Navigation [Nav] or Robotic [Rob]-Assisted surgery. Basic demographics and surgical variables were identified via chi-squared and t tests. Each system was analyzed from 2007 to 2015 for trends in usage. RESULTS: Included 3,759,751 patients: 100,488 Nav; 4724 Rob. Nav were younger (56.7 vs 62.7 years), had lower comorbidity index (1.8 vs 6.2, all p < 0.05), more decompressions (79.5 vs 42.6%) and more fusions (60.3 vs 52.6%) than Rob. From 2007 to 2015, incidence of complication increased for Nav (from 5.8 to 21.7%) and Rob (from 3.3 to 18.4%) as well as 2-3 level fusions (from 50.4 to 52.5%) and (from 1.3 to 3.2%); respectively. Invasiveness increased for both (Rob: from 1.7 to 2.2; Nav: from 3.7 to 4.6). Posterior approaches (from 27.4 to 41.3%), osteotomies (from 4 to 7%), and fusions (from 40.9 to 54.2%) increased in Rob. Anterior approach for Rob decreased from 14.9 to 14.4%. Nav increased posterior (from 51.5% to 63.9%) and anterior approaches (from 16.4 to 19.2%) with an increase in osteotomies (from 2.1 to 2.7%) and decreased decompressions (from 73.6 to 63.2%). CONCLUSIONS: From 2007 to 2015, robotic and navigation systems have been performed on increasingly invasive spine procedures. Robotic systems have shifted from anterior to posterior approaches, whereas navigation computer-assisted procedures have decreased in rates of usage for decompression procedures.

The impact of baseline cervical malalignment on the development of proximal junctional kyphosis following surgical correction of thoracolumbar adult spinal deformity.

OBJECTIVE: The objective of this study was to identify the effect of baseline cervical deformity (CD) on proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in patients with adult spinal deformity (ASD). METHODS: This study was a retrospective analysis of a prospectively collected, multicenter database comprising ASD patients enrolled at 13 participating centers from 2009 to 2018. Included were ASD patients aged > 18 years with concurrent CD (C2-7 kyphosis < -15°, T1S minus cervical lordosis > 35°, C2-7 sagittal vertical axis > 4 cm, chin-brow vertical angle > 25°, McGregor's slope > 20°, or C2-T1 kyphosis > 15° across any three vertebrae) who underwent surgery. Patients were grouped according to four deformity classification schemes: Ames and Passias CD modifiers, sagittal morphotypes as described by Kim et al., and the head versus trunk balance system proposed by Mizutani et al. Mean comparison tests and multivariable binary logistic regression analyses were performed to assess the impact of these deformity classifications on PJK and PJF rates up to 3 years following surgery. RESULTS: A total of 712 patients with concurrent ASD and CD met the inclusion criteria (mean age 61.7 years, 71% female, mean BMI 28.2 kg/m2, and mean Charlson Comorbidity Index 1.90) and underwent surgery (mean number of levels fused 10.1, mean estimated blood loss 1542 mL, and mean operative time 365 minutes; 70% underwent osteotomy). By approach, 59% of the patients underwent a posterior-only approach and 41% underwent a combined approach. Overall, 277 patients (39.1%) had PJK by 1 year postoperatively, and an additional 189 patients (26.7%) developed PJK by 3 years postoperatively. Overall, 65 patients (9.2%) had PJF by 3 years postoperatively. Patients classified as having a cervicothoracic deformity morphotype had higher rates of early PJK than flat neck deformity and cervicothoracic deformity patients (p = 0.020). Compared with the head-balanced patients, trunk-balanced patients had higher rates of PJK and PJF (both p < 0.05). Examining Ames modifier severity showed that patients with moderate and severe deformity by the horizontal gaze modifier had higher rates of PJK (p < 0.001). CONCLUSIONS: In patients with concurrent cervical and thoracolumbar deformities undergoing isolated thoracolumbar correction, the use of CD classifications allows for preoperative assessment of the potential for PJK and PJF that may aid in determining the correction of extending fusion levels.

Natural history of adult spinal deformity: how do patients with suboptimal surgical outcomes fare relative to nonoperative counterparts?

OBJECTIVE: Management of adult spinal deformity (ASD) has increasingly favored operative intervention; however, the incidence of complications and reoperations is high, and patients may fail to achieve idealized postsurgical results. This study compared health-related quality of life (HRQOL) metrics between patients with suboptimal surgical outcomes and those who underwent nonoperative management as a proxy for the natural history (NH) of ASD. METHODS: ASD patients with 2-year data were included. Patients who were offered surgery but declined were considered nonoperative (i.e., NH) patients. Operative patients with suboptimal outcome (SOp)-defined as any reoperation, major complication, or ≥ 2 severe Scoliosis Research Society (SRS)-Schwab modifiers at follow-up-were selected for comparison. Propensity score matching (PSM) on the basis of baseline age, deformity, SRS-22 Total, and Charlson Comorbidity Index score was used to match the groups. ANCOVA and stepwise logistic regression analysis were used to assess outcomes between groups at 2 years. RESULTS: In total, 441 patients were included (267 SOp and 174 NH patients). After PSM, 142 patients remained (71 SOp 71 and 71 NH patients). At baseline, the SOp and NH groups had similar demographic characteristics, HRQOL, and deformity (all p > 0.05). At 2 years, ANCOVA determined that NH patients had worse deformity as measured with sagittal vertical axis (36.7 mm vs 21.3 mm, p = 0.025), mismatch between pelvic incidence and lumbar lordosis (11.9° vs 2.9°, p < 0.001), and pelvic tilt (PT) (23.1° vs 20.7°, p = 0.019). The adjusted regression analysis found that SOp patients had higher odds of reaching the minimal clinically important differences in Oswestry Disability Index score (OR [95% CI] 4.5 [1.7-11.5], p = 0.002), SRS-22 Activity (OR [95% CI] 3.2 [1.5-6.8], p = 0.002), SRS-22 Pain (OR [95% CI] 2.8 [1.4-5.9], p = 0.005), and SRS-22 Total (OR [95% CI] 11.0 [3.5-34.4], p < 0.001). CONCLUSIONS: Operative patients with SOp still experience greater improvements in deformity and HRQOL relative to the progressive radiographic and functional deterioration associated with the NH of ASD. The NH of nonoperative management should be accounted for when weighing the risks and benefits of operative intervention for ASD.

Failure to Normalize Risk Profile of Spine Fusion Patients With Coronary Artery Disease Previously Treated With Percutaneous Stent Revascularization.

BACKGROUND: The impact of an initially less invasive cardiac intervention on outcomes of future surgical spine procedures has been understudied; therefore, we sought to investigate the effect of coronary stents on postoperative outcomes in an elective spine fusion cohort. METHODS: Elective spine fusion patients were isolated with International Classification of Diseases-Ninth Edition and current procedural terminology procedure codes in the PearlDiver database. Patients were stratified by number of coronary stents: (1) 1 to 2 stents (ST12); (2) 3 to 4 stents (ST34); (3) no stents. Mean comparison tests compared differences in demographics, diagnoses, comorbidities, and 30-day and 90-day complication outcomes. Logistic regression assessed the odds of complications associated with coronary stents, controlling for levels fused, age, sex, and comorbidities (odds ratio [95% confidence interval]). Statistical significance was P < 0.05. RESULTS: A total of 726,061 elective spine fusion patients were isolated. Of those patients, 707,396 patients had no stent, 17,087 ST12, and 1578 ST34. At baseline (BL), ST12 patients had higher rates of morbid obesity, chronic kidney disease, congestive heart failure, chronic obstructive pulmonary disease, and diabetes mellitus compared with no stent and ST34 patients (all P < 0.001). Relative to no stent patients, ST12 patients had a longer length of stay and, at 30 days, significantly higher complication rates, including pneumonia, myocardial infarction (MI), sepsis, acute kidney injury, urinary tract infection (UTI), wound complications, transfusions, and 30-day readmissions (P < 0.05). Controlling for age, sex, comorbidities, and levels fused, ST12 was a significant predictor of MI within 30 days (OR 2.15 [95% CI 1.7-2.7], P < 0.001) and 90 days postoperatively (OR 1.87 [95% CI 1.6-2.2], P < 0.001). ST34 patients compared with no stent patients at 30 days presented with increased rates of complication, including pneumonia, MI, sepsis, UTI, wound complications, and 30-day readmissions. Regression analysis showed no significant differences in complications between ST12 vs ST34 at 30 days, but at 90 days, ST34 was associated with significantly increased rate and odds of death (1.1% vs 0.3%, P = 0.021; OR 1.94 [95% CI 1.13-3.13], P = 0.01). CONCLUSION: Cardiac stents failed to normalize risk profile of patients with coronary artery disease. Postoperatively at 90 days, elective spine fusion patients with 3 or more stents were significantly at risk of mortality compared with patients with fewer or no stents.

Predictors of Complication Severity Following Adult Spinal Deformity Surgery: Smoking Rate, Diabetes, and Osteotomy Increase Risk of Severe Adverse Events.

BACKGROUND: Given the physical and economic burden of complications in spine surgery, reducing the prevalence of perioperative adverse events is a primary concern of both patients and health care professionals. This study aims to identify specific perioperative factors predictive of developing varying grades of postoperative complications in adult spinal deformity (ASD) patients, as assessed by the Clavien-Dindo complication classification (Cc) system. METHODS: Surgical ASD patients ≥18 years were identified in the American College of Surgeons' National Surgical Quality Improvement Program from 2005 to 2015. Postoperative complications were stratified by Cc grade severity: minor (I, II, and III) and severe (IV and V). Stepwise regression models generated dataset-specific predictive models for Cc groups. Model internal validation was achieved by bootstrapping and calculating the area under the curve (AUC) of the model. Significance was set at P < 0.05. RESULTS: Included were 3936 patients (59 ± 16 years, 63% women, 29 ± 7 kg/m2) undergoing surgery for ASD (4.4 ± 4.7 levels, 71% posterior approach, 11% anterior, and 18% combined). Overall, 1% of cases were revisions, 39% of procedures involved decompression, 27% osteotomy, and 15% iliac fixation. Additionally, 66% of patients experienced at least 1 complication, 0% of which were Cc grade I, 51% II, 5% III, 43% IV, and 1% V. The final model predicting severe Cc (IV-V) complications yielded an AUC of 75.6% and included male sex, diabetes, increased operative time, central nervous system tumor, osteotomy, cigarette pack-years, anterior decompression, and anterior lumbar interbody fusion. Final models predicting specific Cc grades were created. CONCLUSIONS: Specific predictors of adverse events following ASD-corrective surgery varied for complications of different severities. Multivariate modeling showed smoking rate, osteotomy, diabetes, anterior lumbar interbody fusion, and higher operative time, among other factors, as predictive of severe complications, as classified by the Clavien-Dindo Cc system. These factors can help in the identification of high-risk patients and, consequently, improve preoperative patient counseling. CLINICAL RELEVANCE: The findings of this study provide a foundation for identifying ASD patients at high risk of postoperative complications .

External Validation of the National Surgical Quality Improvement Program Calculator Utilizing a Single Institutional Experience for Adult Spinal Deformity Corrective Surgery.

BACKGROUND: Identify the external applicability of the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) risk calculator in the setting of adult spinal deformity (ASD) and subsets of patients based on deformity and frailty status. METHODS: ASD patients were isolated in our single-center database and analyzed for the shared predictive variables displayed in the NSQIP calculator. Patients were stratified by frailty (not frail <0.03, frail 0.3-0.5, severely frail >0.5), deformity [T1 pelvic angle (TPA) > 30, pelvic incidence minus lumbar lordosis (PI-LL) > 20], and reoperation status. Brier scores were calculated for each variable to validate the calculator's predictability in a single center's database (Quality). External validity of the calculator in our ASD patients was assessed via Hosmer-Lemeshow test, which identified whether the differences between observed and expected proportions are significant. RESULTS: A total of 1606 ASD patients were isolated from the Quality database (48.7 years, 63.8% women, 25.8 kg/m2); 33.4% received decompressions, and 100% received a fusion. For each subset of ASD patients, the calculator predicted lower outcome rates than what was identified in the Quality database. The calculator showed poor predictability for frail, deformed, and reoperation patients for the category "any complication" because they had Brier scores closer to 1. External validity of the calculator in each stratified patient group identified that the calculator was not valid, displaying P values >0.05. CONCLUSION: The NSQIP calculator was not a valid calculator in our single institutional database. It is unable to comment on surgical complications such as return to operating room, surgical site infection, urinary tract infection, and cardiac complications that are typically associated with poor patient outcomes. Physicians should not base their surgical plan solely on the NSQIP calculator but should consider multiple preoperative risk assessment tools.

The Effects of Global Alignment and Proportionality Scores on Postoperative Outcomes After Adult Spinal Deformity Correction.

BACKGROUND: Recent studies have suggested achieving global alignment and proportionality (GAP) alignment may influence mechanical complications after adult spinal deformity (ASD) surgery. OBJECTIVE: To investigate the association between the GAP score and mechanical complications after ASD surgery. METHODS: Patients with ASD with at least 5-level fusion to pelvis and minimum 2-year data were included. Multivariate analysis was used to find an association between proportioned (P), GAP-moderately disproportioned, and severely disproportioned (GAP-SD) states and mechanical complications (inclusive of proximal junctional kyphosis [PJK], proximal junctional failure [PJF], and implant-related complications [IC]). Severe sagittal deformity was defined by a "++" in the Scoliosis Research Society (SRS)-Schwab criteria for sagittal vertebral axis or pelvic incidence and lumbar lordosis. RESULTS: Two hundred ninety patients with ASD were included. Controlling for age, Charlson comorbidity index, invasiveness and baseline deformity, and multivariate analysis showed no association of GAP-moderately disproportioned patients with proximal junctional kyphosis, PJF, or IC, while GAP-SD patients showed association with IC (odds ratio [OR]: 1.7, [1.1-3.3]; P = .043). Aligning in GAP-relative pelvic version led to lower likelihood of all 3 mechanical complications (all P < .04). In patients with severe sagittal deformity, GAP-SD was predictive of IC (OR: 2.1, [1.1-4.7]; P = .047), and in patients 70 years and older, GAP-SD was also predictive of PJF development (OR: 2.5, [1.1-14.9]; P = .045), while improving in GAP led to lower likelihood of PJF (OR: 0.2, [0.02-0.8]; P = .023). CONCLUSION: Severely disproportioned in GAP is associated with development of any IC and junctional failure specifically in older patients and those with severe baseline deformity. Therefore, incorporation of patient-specific factors into realignment goals may better strengthen the utility of this novel tool.