Impact of Myelopathy Severity and Degree of Deformity on Postoperative Outcomes in Cervical Spinal Deformity Patients

Objective Malalignment of the cervical spine can result in cord compression, leading to a myelopathy diagnosis. Whether deformity or myelopathy severity is stronger predictors of surgical outcomes is understudied. Methods Surgical cervical deformity (CD) patients with baseline (BL) and up to 1-year data were included. Modified Japanese Orthopaedic Association (mJOA) score categorized BL myelopathy (mJOA = 18 excluded), with moderate myelopathy mJOA being 12 to 17 and severe myelopathy being less than 12. BL deformity severity was categorized using the mismatch between T1 slope and cervical lordosis (TS-CL), with CL being the angle between the lower endplates of C2 and C7. Moderate deformity was TS-CL less than or equal to 25° and severe deformity was greater than 25°. Categorizations were combined into 4 groups: group 1 (G1), severe myelopathy and severe deformity; group 2 (G2), severe myelopathy and moderate deformity; group 3 (G3), moderate myelopathy and moderate deformity; group 4 (G4), moderate myelopathy and severe deformity. Univariate analyses determined whether myelopathy or deformity had greater impact on outcomes. Results One hundred twenty-eight CD patients were included (mean age, 56.5 years; 46% female; body mass index, 30.4 kg/m2) with a BL mJOA score of 12.8±2.7 and mean TS-CL of 25.9°±16.1°. G1 consisted of 11.1% of our CD population, with 21% in G2, 34.6% in G3, and 33.3% in G4. At BL, Neck Disability Index (NDI) was greatest in G2 (p=0.011). G4 had the lowest EuroQol-5D (EQ-5D) (p<0.001). Neurologic exam factors were greater in severe myelopathy (p<0.050). At 1-year, severe deformity met minimum clinically important differences (MCIDs) for NDI more than moderate deformity (p=0.002). G2 had significantly worse outcomes compared to G4 by 1-year NDI (p=0.004), EQ-5D (p=0.028), Numerical Rating Scale neck (p=0.046), and MCID for NDI (p=0.001). Conclusion Addressing severe deformity had increased clinical weight in improving patient-reported outcomes compared to addressing severe myelopathy

Predictors of reoperation for spinal disorders in Chiari malformation patients with prior surgical decompression

Background: Chiari malformation (CM) is a cluster of related developmental anomalies of the posterior fossa ranging from asymptomatic to fatal. Cranial and spinal decompression can help alleviate symptoms of increased cerebrospinal fluid pressure and correct spinal deformity. As surgical intervention for CM increases in frequency, understanding predictors of reoperation may help optimize neurosurgical planning. Materials and Methods: This was a retrospective analysis of the prospectively collected Healthcare Cost and Utilization Project's California State Inpatient Database years 2004–2011. Chiari malformation Types 1–4 (queried with ICD-9 CM codes) with associated spinal pathologies undergoing stand-alone spinal decompression (queried with ICD-9 CM procedure codes) were included. Cranial decompressions were excluded. Results: One thousand four hundred and forty-six patients (29.28 years, 55.6% of females) were included. Fifty-eight patients (4.01%) required reoperation (67 reoperations). Patients aged 40–50 years had the most reoperations (11); however, patients aged 15–20 years had a significantly higher reoperation rate than all other groups (15.5% vs. 8.2%, P = 0.048). Female gender was significantly associated with reoperation (67.2% vs. 55.6%, P = 0.006). Medical comorbidities associated with reoperation included chronic lung disease (19% vs. 6.9%, P < 0.001), iron deficiency anemia (10.3% vs. 4.1%, P = 0.024), and renal failure (3.4% vs. 0.9%, P = 0.05). Associated significant cluster anomalies included spina bifida (48.3% vs. 34.8%, P = 0.035), tethered cord syndrome (6.9% vs. 2.1%, P = 0.015), syringomyelia (12.1% vs. 5.9%, P = 0.054), hydrocephalus (37.9% vs. 17.7%, P < 0.001), scoliosis (13.8% vs. 6.4%, P = 0.028), and ventricular septal defect (6.9% vs. 2.3%, P = 0.026). Conclusions: Multiple medical and CM-specific comorbidities were associated with reoperation. Addressing them, where possible, may aid in improving CM surgery outcomes

Predicting development of severe clinically relevant distal junctional kyphosis following adult cervical deformity surgery, with further distinction from mild asymptomatic episodes.

OBJECTIVE: This retrospective cohort study aimed to develop a formal predictive model distinguishing between symptomatic and asymptomatic distal junctional kyphosis (DJK). In this study the authors identified a DJK rate of 32.2%. Predictive models were created that can be used with high reliability to help distinguish between severe symptomatic DJK and mild asymptomatic DJK through the use of surgical factors, radiographic parameters, and patient variables. METHODS: Patients with cervical deformity (CD) were stratified into asymptomatic and symptomatic DJK groups. Symptomatic: 1) DJK angle (DJKA) \u3e 10° and either reoperation due to DJK or \u3e 1 new-onset neurological sequela related to DJK; or 2) either a DJKA \u3e 20° or ∆DJKA \u3e 20°. Asymptomatic: ∆DJK \u3e 10° in the absence of neurological sequelae. Stepwise logistic regressions were used to identify factors associated with these types of DJK. Decision tree analysis established cutoffs. RESULTS: A total of 99 patients with CD were included, with 32.2% developing DJK (34.3% asymptomatic, 65.7% symptomatic). A total of 37.5% of asymptomatic patients received a reoperation versus 62.5% symptomatic patients. Multivariate analysis identified independent baseline factors for developing symptomatic DJK as follows: pelvic incidence (OR 1.02); preoperative cervical flexibility (OR 1.04); and combined approach (OR 6.2). Having abnormal hyperkyphosis in the thoracic spine, more so than abnormal cervical lordosis, was a factor for developing symptomatic disease when analyzed against asymptomatic patients (OR 1.2). Predictive modeling identified factors that were predictive of symptomatic versus no DJK, as follows: myelopathy (modified Japanese Orthopaedic Association score 12-14); combined approach; uppermost instrumented vertebra C3 or C4; preoperative hypermobility; and \u3e 7 levels fused (area under the curve 0.89). A predictive model for symptomatic versus asymptomatic disease (area under the curve 0.85) included being frail, T1 slope minus cervical lordosis \u3e 20°, and a pelvic incidence \u3e 46.3°. Controlling for baseline deformity and disability, symptomatic patients had a greater cervical sagittal vertical axis (4-8 cm: 47.6% vs 27%) and were more malaligned according to their Scoliosis Research Society sagittal vertical axis measurement (OR 0.1) than patients without DJK at 1 year (all p \u3c 0.05). Despite their symptomatology and higher reoperation rate, outcomes equilibrated in the symptomatic cohort at 1 year following revision. CONCLUSIONS: Overall, 32.2% of patients with CD suffered from DJK. Symptomatic DJK can be predicted with high reliability. It can be further distinguished from asymptomatic occurrences by taking into account pelvic incidence and baseline cervicothoracic deformity severity

At What Point Should the Thoracolumbar Region be Addressed In Patients Undergoing Corrective Cervical Deformity Surgery?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to investigate the impact of cervical to thoracolumbar ratios on poor outcomes in cervical deformity (CD) corrective surgery. SUMMARY OF BACKGROUND DATA: Consideration of distal regional and global alignment is a critical determinant of outcomes in CD surgery. For operative CD patients, it is unknown whether certain thoracolumbar parameters play a significant role in poor outcomes and whether addressing such parameters is warranted. METHODS: Included: surgical CD patients (C2-C7 Cobb \u3e10°, cervical lordosis [CL] \u3e10°, C2-C7 sagittal vertical axis (cSVA) \u3e4 cm, or chin-brow vertical angle \u3e25°) with baseline and 1-year data. Patients were assessed for ratios of preop cervical and global parameters including: C2 Slope/T1 slope, T1 slope minus C2-C7 lordosis (TS-CL)/mismatch between pelvic incidence and lumbar lordosis (PI-LL), cSVA/sagittal vertical axis (SVA). Deformity classification ratios of cervical (Ames-ISSG) to spinopelvic (SRS-Schwab) were investigated: cSVA modifier/SVA modifier, TS-CL modifier/PI-LL modifier. Cervical to thoracic ratios included C2-C7 lordosis/T4-T12 kyphosis. Correlations assessed the relationship between ratios and poor outcomes (major complication, reoperation, distal junctional kyphosis (DJK), or failure to meet minimal clinically important difference [MCID]). Decision tree analysis through multiple iterations of multivariate regressions assessed cut-offs for ratios for acquiring suboptimal outcomes. RESULTS: A total of 110 CD patients were included (61.5 years, 66% F, 28.8 kg/m2). Mean preoperative radiographic ratios calculated: C2 slope/T1 slope of 1.56, TS-CL/PI-LL of 11.1, cSVA/SVA of 5.4, CL/thoracic kyphosis (TK) of 0.26. Ames-ISSG and SRS-Schwab modifier ratios: cSVA/SVA of 0.1 and TS-CL/PI-LL of 0.35. Pearson correlations demonstrated a relationship between major complications and baseline TS-CL/PI-LL, Ames TS-CL/Schwab PI-LL modifiers, and the CL/TK ratios (P \u3c 0.050). Reoperation had significant correlation with TS-CL/PI-LL and cSVA/SVA ratios. Postoperative DJK correlated with C2 slope/T1 slope and CL/TK ratios. Not meeting MCID for Neck Disability Index (NDI) correlated with CL/TK ratio and not meeting MCID for EQ5D correlated with Ames TS-CL/Schwab PI-LL. CONCLUSION: Consideration of cervical to global alignment is a critical determinant of outcomes in CD corrective surgery. Key ratios of cervical to global alignment correlate with suboptimal clinical outcomes. A larger cervical lordosis to TK predicted postoperative complication, DJK, and not meeting MCID for NDI.Level of Evidence: 4

A Risk Benefit Analysis of Increasing Surgical Invasiveness Relative to Frailty Status in Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective review of a prospectively enrolled multicenter Adult Spinal Deformity (ASD) database. OBJECTIVE: Investigate invasiveness and outcomes of ASD surgery by frailty state. SUMMARY OF BACKGROUND DATA: The ASD Invasiveness Index incorporates deformity-specific components to assess correction magnitude. Intersections of invasiveness, surgical outcomes, and frailty state are understudied. METHODS: ASD patients with baseline and 3-year (3Y) data were included. Logistic regression analyzed the relationship between increasing invasiveness and major complications or reoperations and meeting minimal clinically important differences (MCID) for health-related quality of life (HRQL) measures at 3Y. Decision tree analysis assessed invasiveness risk-benefit cut-off points, above which experiencing complications or reoperations and not reaching MCID were higher. Significance was set to p \u3c 0.05. RESULTS: Overall, 195/322 patients were included. Baseline demographics: age 59.9 ± 14.4, 75% female, BMI 27.8 ± 6.2, mean Charlson Comorbidity Index: 1.7 ± 1.7. Surgical information: 61% osteotomy, 52% decompression, 11.0 ± 4.1 levels fused. There were 98 not frail (NF), 65 frail (F), and 30 severely frail (SF) patients. Relationships were found between increasing invasiveness and experiencing a major complication or reoperation for the entire cohort and by frailty group (all p \u3c 0.05). Defining a favorable outcome as no major complications or reoperation and meeting MCID in any HRQL at 3Y established an invasiveness cut-off of 63.9. Patients below this threshold were 1.8[1.38-2.35] (p \u3c 0.001) times more likely to achieve favorable outcome. For NF patients, the cut-off was 79.3 (2.11[1.39-3.20] (p \u3c 0.001), 111 for F (2.62 [1.70-4.06] (p \u3c 0.001), and 53.3 for SF (2.35[0.78-7.13] (p = 0.13). CONCLUSIONS: Increasing invasiveness is associated with increased odds of major complications and reoperations. Risk-benefit cut-offs for successful outcomes were 79.3 for NF, 111 for F, and 53.3 for SF patients. Above these, increasing invasiveness has increasing risk of major complications or reoperations and not meeting MCID at 3Y.Level of Evidence: 3

Predictive Analytics for Determining Extended Operative Time in Corrective Adult Spinal Deformity Surgery.

BackgroundMore sophisticated surgical techniques for correcting adult spinal deformity (ASD) have increased operative times, adding to physiologic stress on patients and increased complication incidence. This study aims to determine factors associated with operative time using a statistical learning algorithm.MethodsRetrospective review of a prospective multicenter database containing 837 patients undergoing long spinal fusions for ASD. Conditional inference decision trees identified factors associated with skin-to-skin operative time and cutoff points at which factors have a global effect. A conditional variable-importance table was constructed based on a nonreplacement sampling set of 2000 conditional inference trees. Means comparison for the top 15 variables at their respective significant cutoffs indicated effect sizes.ResultsIncluded: 544 surgical ASD patients (mean age: 58.0 years; fusion length 11.3 levels; operative time: 378 minutes). The strongest predictor for operative time was institution/surgeon. Center/surgeons, grouped by decision tree hierarchy, a and b were, on average, 2 hours faster than center/surgeons c-f, who were 43 minutes faster than centers g-j, all P &lt; 0.001. The next most important predictors were, in order, approach (combined vs posterior increases time by 139 minutes, P &lt; 0.001), levels fused (&lt;4 vs 5-9 increased time by 68 minutes, P &lt; 0.050; 5-9 vs &lt; 10 increased time by 47 minutes, P &lt; 0.001), age (age &lt;50 years increases time by 57 minutes, P &lt; 0.001), and patient frailty (score &lt;1.54 increases time by 65 minutes, P &lt; 0.001). Surgical techniques, such as three-column osteotomies (35 minutes), interbody device (45 minutes), and decompression (48 minutes), also increased operative time. Both minor and major complications correlated with &lt;66 minutes of increased operative time. Increased operative time also correlated with increased hospital length of stay (LOS), increased estimated intraoperative blood loss (EBL), and inferior 2-year Oswestry Disability Index (ODI) scores.ConclusionsProcedure location and specific surgeon are the most important factors determining operative time, accounting for operative time increases &lt;2 hours. Surgical approach and number of levels fused were also associated with longer operative times, respectively. Extended operative time correlated with longer LOS, higher EBL, and inferior 2-y ODI outcomes.Clinical relevanceWe further identified the poor outcomes associated with extended operative time during surgical correction of ASD, and attributed the useful predictors of time spent in the operating room, including site, surgeon, surgical approach, and the number of levels fused.Level of evidence:

Risk-benefit assessment of major versus minor osteotomies for flexible and rigid cervical deformity correction.

Introduction: Osteotomies are commonly performed to correct sagittal malalignment in cervical deformity (CD). However, the risks and benefits of performing a major osteotomy for cervical deformity correction have been understudied. The objective of this retrospective cohort study was to investigate the risks and benefits of performing a major osteotomy for CD correction. Methods: Patients stratified based on major osteotomy (MAJ) or minor (MIN). Independent Results: 137 CD patients were included (62 years, 65% F). 19.0% CD patients underwent a MAJ osteotomy. After propensity score matching for cSVA, 52 patients were included. About 19.0% CD patients underwent a MAJ osteotomy. MAJ patients had more minor complications ( Conclusions: Cervical deformity patients who underwent a major osteotomy had similar clinical outcomes at 3-months but worse outcomes at 1-year as compared to minor osteotomies, likely due to differences in baseline deformity. Patients with rigid deformities who underwent a major osteotomy had higher complication rates and worse clinical improvement despite similar realignment at 1 year