ABSTRACT Background The relative benefit of neoadjuvant therapies remains controversial for patients with (borderline) resectable pancreatic ductal adenocarcinoma (PDAC). The purpose of this study was to create a model to predict response to multiagent neoadjuvant chemotherapy (NAC) followed by radiotherapy with elective nodal irradiation (ENI). Methods Using the National Cancer Database (NCDB), we identified patients with cT1‐4N0M0 PDAC diagnosed between 2006 and 2020 treated with multiagent NAC, radiation with ENI, followed by curative resection with nodal dissection. A LASSO logistic regression model was used to predict ypN0 status, with generation of a nomogram and assessment of outcomes in training and testing cohorts. Secondary endpoints of negative‐margin resection and overall survival were also examined. Out‐of‐sample predictions were then made on a separate ENI‐naïve cohort, with similar assessments of selected outcomes. The threshold for statistical significance was set to p < 0.05. Results A total of 1053 patients were identified with a median age of 64.0 years (IQR = 57–70 years). The final model included pancreatic body tumor location, clinical T stage, time from diagnosis to radiation therapy and surgery, ENI dose, and duration of NAC, among others. Patients predicted for treatment response were more likely to be ypN0 (71.5% vs. 29.7%, p < 0.001), had more R0 resections (87.3% vs. 62.6%, p < 0.001), and improved OS after accounting for competing risks of perioperative death (SHR = 0.64, 95% CI = 0.46–0.89, p = 0.008). A similar significant trend was noted in the ENI‐naïve cohort (N = 1258). Model AUC was 0.718 and 0.725 in training and testing cohorts, respectively. Conclusions Using a machine learning approach, we define a nomogram capable of predicting treatment response to multiagent NAC followed by radiotherapy with or without ENI. Patients selected by this model had higher rates of ypN0, higher R0 resection rates, and improved OS.

Financial toxicity, defined as hardship from medical costs, is an emerging concept in healthcare. Here we define financial toxicity in head and neck cancer patients receiving radiation, identify risk factors, and determine associations with HRQoL, treatment morbidity, and survival. We conducted a prospective study on consecutive patients referred to a tertiary referral center for radiation therapy for head and neck malignancies (July 2021–June 2023). Patients provided consent and were assessed using validated patient-reported outcome measures for financial toxicity (FACIT-COST), HRQoL (EORTC-QLQ-C30), and symptom burden (PRO-CTCAE) before and after radiation therapy. Primary outcomes included two-year overall survival (OS), treatment morbidity (ER visits, hospitalizations, feeding tube placement, missed radiation days), HRQoL, and symptom burden. Among 74 patients (median age 69), all completed pre-radiation therapy (pre-RT) measures, and 39 completed post-RT measures. Median pre-RT COST was 29 (range: 0–44), with 41.9

e16563 Background: ACEis and ARBs are commonly used in the management of hypertension and cardiovascular disease, but little is known about their safety and impact on renal clearance when used in patients with bladder and upper tract malignancies receiving platinum-based chemotherapy (PBC). Methods: We performed an IRB-approved retrospective analysis of patients with bladder and upper tract malignancies at the University of California, Irvine, who received PBC between November 2017 and July 2023. Patients were grouped into cohort 1 (PBC + ACEis/ARBs) and cohort 2 (PBC without ACEis/ARBs). We used Chi-square tests for categorical variables and Student’s t-tests for continuous variables, with logistic regression to identify independent risk factors. Results: A total of 145 patients (mean age: 70) were included, with 47/145 (32%) receiving ACEis/ARBs at chemotherapy initiation. 64/145 (44%) were treated for metastatic disease and 11/145 (7.6%) received chemoradiation. Cisplatin was given to 84/145 (57.9%), carboplatin to 58/145 (40%). While chemotherapy regimen modifications (dose reductions, delays, cessations) were more frequent in cohort 1, the difference was not statistically significant (66% vs. 51%, P = 0.09). Independent risk factors associated with any regimen alterations included older age (in years) (aOR, 1.06; 95% CI, 1.02 to 1.10; P = 0.001) and receipt of carboplatin (aOR, 2.11; 95% CI, 1.01 to 4.40; P = 0.046). Chemotherapy-induced cytopenia was found in 32/47 (68.1%) of patients in cohort 1 vs. (56/98) 57.1% of patients in cohort 2, P = 0.21). No significant differences in acute kidney injury (P = 0.57) or hospitalization rates (P = 0.18) were observed. In multivariable logistic regression analysis, older age (aOR, 1.09; 95% CI, 1.05 to 1.14; P < 0.001) and metastatic disease (aOR, 2.41; 95% CI, 1.08 to 5.35; P = 0.031) were associated with any cytopenia or AKI. Conclusions: Concurrent use of ACEis/ARBs in bladder and upper tract cancer patients receiving PBC was associated with trends toward higher chemotherapy-induced toxicities and treatment alterations, though these findings were not statistically significant. Older age and metastatic disease were associated with cytopenias or AKI. These trends are worth exploring further in larger studies to ensure patient safety and treatment efficacy.

Purpose: Pelvic lymph node metastases (ypN+) after multiagent neoadjuvant chemotherapy (NAC) is a poor prognostic sign in nonmetastatic muscle-invasive bladder cancer (nmMIBC). We sought to create a nomogram predicting probability of ypN+ after NAC for cN0 nmMIBC and determine association with overall survival (OS). Methods and Materials: We reviewed the National Cancer Database for patients with cT2-4N0M0 urothelial carcinoma of the bladder receiving multiagent NAC and surgery from 2004 to 2020. Following a data split, univariate logistic regression identified variables associated with ypN+ at P < .05. Eligible variables were used for multivariate logistic regression and nomogram generation. A threshold for 95% sensitivity defined high- and low-risk groups for ypN+. Fine-Gray models assessed ypN+ risk group and OS, accounting for competing risks of surgical mortality. Results: A total of 6194 patients were identified with a median follow-up of 39.5 months (interquartile range [IQR], 20.5-67.2 months). Most patients had high-grade (97.7%) cT2 disease (70.8%) with nonpapillary urothelial histology (67.3%) and initiated NAC at a median of 41.0 days after diagnosis (IQR, 28.0-59.0 days).The nomogram included age in decades (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.87-1.03; P = .172), weeks from diagnosis to NAC (OR, 1.02; 95% CI, 1.01-1.04; P = .004), nonpapillary histology (OR, 1.17; 95% CI, 0.99-1.39; P = .068), and clinical T-stage. Within the testing cohort, ypN+ was found in 392 (22.8%) high-risk and 12 (8.0%) low-risk patients (P < .001), with median OS of 36.1 and 74.0 months, respectively (P < .001). High-risk patients had worse OS despite competing risks of 30-day (subdistribution hazard ratio [SHR], 1.80; 95% CI, 1.49-2.18; P < .001) and 90-day surgical mortality (SHR, 1.68; 95% CI, 1.39-2.04; P < .001). Conclusions: This is the first study to provide a tool for predicting ypN+ and prognosticate worse OS in primarily high-grade nmMIBC and could select patients for alternative neoadjuvant therapy and facilitate future study. (c) 2024 The Author(s). Published by Elsevier Inc. on behalf of American Society for Radiation Oncology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Purpose This study aimed to identify factors associated with delays in initiating early salvage radiation therapy in prostate cancer patients with prostate-specific antigen (PSA) failure after prostatectomy. Methods We conducted a single-institution, retrospective study of patients receiving salvage radiation therapy after radical prostatectomy from 2011 to 2022. Patient demographics and clinical data were examined to identify factors that may have influenced the time to start of radiation therapy after surgery. Utilizing a PSA cut off of 0.25 ng/ml or less, we classified patients as receiving either early "PSA low" or late "PSA high" salvage therapy depending on their PSA at the time of initiating treatment. Results Of the 81 patients evaluated, the median age was 61.9 years (IQR 57.9 - 66.5), with most presenting with pT3 (65.4%), Grade Group 2 disease (35.8%), and positive margins 55%). Median PSA at salvage radiation therapy commencement was 0.30 ng/mL (0.18 - 0.48). 40 patients completed early salvage and 41 patients completed late salvage in the overall cohort. A significant association was found between patient insurance carrier and pre-radiation PSA levels. Patients with HMO (Health Maintenance Organization) or PPO (Preferred Provider Organization) insurance were more likely to complete late salvage radiation compared to non-managed Medicare patients (HMO OR 4.0, p <0.05 & PPO OR 3.3 p <0.05 vs non-managed Medicare). All uninsured patients in the cohort received late salvage radiation. Conclusions Insurance type was significantly associated with the timing of salvage radiation therapy post-prostatectomy, suggesting a relationship with providers requiring prior authorization (HMO and PPO coverage). This study supports proper PSA surveillance, in particular for those with HMO or PPO coverage.

STUDY DESIGN:Prospective, case series.OBJECTIVE:To identify and characterize any differences in specific patient factors, MRI findings, features of spontaneous disc resorption, and outcomes between patients with single-level and multilevel LDH.BACKGROUND:Lumbar disc herniation (LDH) is one of the most common spinal pathologies worldwide. Though many cases of LDH resolve by spontaneous resorption, the mechanism underlying this "self-healing" phenomenon remains poorly understood, particularly in the context of multilevel herniations.METHODS:A one-year prospective study was conducted of patients presenting with acute symptomatic LDH between 2017 and 2019. Baseline demographics, herniation characteristics, and MRI phenotypes were recorded before treatment, which consisted of gabapentin, acupuncture, and the avoidance of inflammatory-modulating medications. MRIs were performed approximately every three months after the initial evaluation to determine any differences between patients with single-level and multilevel LDH.RESULTS:Ninety patients were included, 17 demonstrated multilevel LDH. Body mass index was higher among patients with multilevel LDH ( P <0.001). Patients with multilevel LDH were more likely to exhibit L3/L4 inferior endplate defects ( P =0.001), L4/L5 superior endplate defects ( P =0.012), and L4/L5 inferior endplate defects ( P =0.020) on MRI. No other differences in MRI phenotypes ( e.g. Modic changes, osteophytes, etc .) existed between groups. Resorption rate and time to resolution did not differ between those with single-level and multilevel LDH.CONCLUSIONS:Resorption rates were similar between single-level and multilevel LDH at various time points throughout one prospective assessment, providing insights that disc healing may have unique programmed signatures. Compared with those with single-level LDH, patients with multilevel herniations were more likely to have a higher BMI, lesser initial axial and sagittal disc measurements, and endplate defects at specific lumbar levels. In addition, our findings support the use of conservative management in patients with LDH, regardless of the number of levels affected.LEVEL OF EVIDENCE:Level 3.

Y-90 Selective Internal Radiotherapy (SIRT) is an ablative therapy used for inoperable liver metastasis. The purpose of this investigation was to examine the impact of local control after SIRT on overall survival (OS) in oligometastatic patients. A retrospective, single-institution study identified oligometastatic patients with ≤5 non-intracranial metastases receiving unilateral or bilateral lobar Y-90 SIRT from 2009 to 2021. The primary endpoint was OS defined from Y-90 SIRT completion to the date of death or last follow-up. Local failure was classified as a progressive disease at the target lesion(s) by RECIST v1.1 criteria starting at 3 months after SIRT. With a median follow-up of 15.7 months, 33 patients were identified who had a total of 79 oligometastatic lesions treated with SIRT, with the majority histology of colorectal adenocarcinoma (n = 22). In total, 94% of patients completed the Y-90 lobectomy. Of the 79 individual lesions treated, 22 (27.8%) failed. Thirteen patients received salvage liver-directed therapy following intrahepatic failure; ten received repeat SIRT. Median OS (mOS) was 20.1 months, and 12-month OS was 68.2%. Intralesional failure was associated with worse 1 y OS (52.3% vs. 86.2%, p = 0.004). These results suggest that intralesional failure following Y-90 may be associated with inferior OS, emphasizing the importance of disease control in low-metastatic-burden patients.

IntroductionThis study investigates the impact of pre- and post-treatment hematologic markers, specifically neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), on treatment outcomes in soft tissue sarcoma (STS) patients undergoing radiation therapy (RT).MethodsData from 64 patients who underwent RT for curative management of STS were reviewed. Pre-RT and post-RT hematologic measures were evaluated for associations with survival outcomes. A normal tissue complication probability (NTCP) curve for predicting ΔPLR ≥ 75 was modeled using a probit function.ResultsElevated baseline NLR was associated with worse overall survival (OS) and disease-free survival (DFS), while elevated PLR was associated with worse DFS. Post-RT, elevated PLR was linked to worse OS and DFS. Increasing PLR change post-RT was associated with worse OS and DFS. Receiver operating characteristics analysis determined ΔPLR ≥ 75 to be a robust cutoff associated with worse DFS. Bone V10Gy ≥362 cc corresponded to a 50% risk of developing ΔPLR ≥ 75.DiscussionThese results suggest that hematologic markers could serve as prognostic biomarkers in both pre- and post-treatment settings for STS patients undergoing RT. Future studies can consider using bone V10Gy < 362 cc as a potential cutoff to reduce the risk of increased PLR after RT.

Purpose: The objectives of this study were to identify key dosimetric parameters associated with postradiation therapy lymphopenia and uncover any effect on clinical outcomes. Methods and Materials: This was a retrospective review of 69 patients (between April 2010 and January 2023) who underwent radiation therapy (RT) as a part of curative intent for soft tissue sarcoma (STS) at a single academic institution. All patients with treatment plans available to review and measurable absolute lymphocyte count (ALC) nadir within a year after completion of RT were included. Results: Median follow-up was 22 months after the start of RT. A decrease in lymphocyte count was noted as early as during treatment and persisted at least 3 months after the completion of RT. On multivariable linear regression, the strongest correlations with ALC nadir were mean body dose, body V10 Gy, mean bone dose, bone V10 Gy, and bone V20 Gy. Five-year overall survival was 60% and 5year disease-free survival was 44%. Advanced T-stage, chemotherapy use, use of intensity-modulated RT, lower ALC nadir, and the development of grade >= 2 lymphopenia at nadir were associated with worse overall survival and disease-free survival. Conclusions: Post-RT lymphopenia was associated with worse outcomes in STS. There were associations between higher body V10 Gy and bone V10 Gy and lower post-RT ALC nadir, despite the varying sites of STS presentation, which aligns with the well-known radiosensitivity of lymphocyte cell lines. These findings support efforts to reduce treatment-related hematopoietic toxicity as a way to improve oncologic outcomes. Additionally, this study supports the idea that the effect of radiation on lymphocyte progenitors in the bone marrow is more significant than that on circulating lymphocytes in treatments with limited involvement of the heart and lung. (c) 2023 The Author(s). Published by Elsevier Inc. on behalf of American Society for Radiation Oncology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Papillary renal cell carcinoma (pRCC) is a rare kidney cancer with limited treatment options and poor outcomes when metastatic. We present a case of a 42-year-old male with metastatic pRCC harboring a somatic ataxia-telangiectasia mutated (ATM) mutation who was treated at our institution. After progression of disease (POD) on ipilimumab/nivolumab, followed by POD on cabozantinib, the patient was treated with radiation therapy to metastatic cervical lymphadenopathy to 60 Gy in 15 fractions as well as retroperitoneal lymphadenopathy to 36 Gy in 9 fractions, which was curtailed due to intolerance. This was followed by sequential systemic therapy with a poly (ADP-ribose) polymerase (PARP) inhibitor and pembrolizumab, which was also discontinued due to adverse effects. Despite not receiving any treatment for 10 months, his disease remains stable. We believe that the prolonged progression-free survival of this patient with ATMmutation metastatic pRCC is likely due to the enhanced sensitivity of the tumor to radiation therapy due to ATM loss.

Abstract Multiple regimens are available for management of mccRCC including either immuno-oncology doublet (IO/IO) or combinations of IO and tyrosine kinase inhibitors (TKI). Clinical trials have compared these regimens to sunitinib, with no direct comparison between them. As such, there is ambiguity among physicians about preferred first-line for mccRCC. We performed a single-institution retrospective study of adults treated in first-line for mccRCC between 1/1/2017 and 1/1/2023. Regimens included IO/IO (ipilimumab/nivolumab [I/N]) or IO/TKI (pembrolizumab/axitinib [P/A], nivolumab/cabozantinib [N/C], or pembrolizumab/lenvatinib [P/L]). We compared efficacy and toxicity endpoints, using Kruskal-Wallis test for medians and Chi-square for categorical variables. 42 patients with median age of 61 (range: 36-95) were included. Patient distribution in IO/IO vs IO/TKI group was 20.0% vs 30.8% in International Metastatic Database Consortium (IMDC) favorable risk, 46.7% vs 38.5% in intermediate-risk, and 33.3% vs 30.8% in poor-risk group. 78.6% vs 66.6% of patients had WHO grade 3/4 ccRCC, 18.8% vs 15.4% had sarcomatoid features in the IO/IO vs IO/TKI, respectively. 38% (16/42) received I/N, 7% (3/42) N/C, 52% (22/42) P/A, and 2% (1/42) P/L. Median follow-up was 109 weeks. Table-1 compares the efficacy of IO/IO vs IO/TKI. IO-related toxicity, TKI-related toxicity, treatment interruptions, dose reductions, and need for steroids were not significantly different between IO/IO and IO/TKI (p= 0.240, p=0.372, p=0.923, p=1.00, and p=0.248, respectively). Genomic characteristics will be reported in poster. Despite small sample size, our real-world data showed that patients treated with IO/IO had significantly worse outcomes compared to those treated with IO/TKI. While this difference may stem from a more aggressive disease in IO/IO group but further insights needs to be obtained through future prospective studies comparing IO/IO and IO/TKI regimens. Variable IO/IO IO/TKI p-value Median treatment duration (weeks) 8.3 59.4 <0.001 Disease control rate (complete response + partial response + stable disease) (%) 50.0 91.7 0.024 Time from 1st line to 2nd line therapy (weeks) 14.6 57.1 0.001 Median overall survival (weeks) 63.6 Not reached 0.001 Citation Format: Omid Yazdanpanah, Sami Dwabe, Garrett Harada, Steven Seyedin, Nataliya Mar. Real-world comparison of first-line treatments for metastatic clear cell renal cell carcinoma (mccRCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 928.

We performed a prospective one-year multi-imaging study to assess the clinical outcomes and rate of disc resorption in acute lumbar disc herniation (LDH) patients undergoing inflammation-preserving treatment (i.e. no NSAIDS, steroids). All patients received gabapentin to relieve leg pain, 12 sessions of acupuncture. Repeat MRI was performed, every 3 months, after 12 sessions of treatment continued for those without 40

Imaging methods of the spine have greatly expanded since 1895, providing anatomical clarity for diagnosis and treatment of the cervical, thoracic, lumbar, and sacral vertebrae. The complex anatomy of the vertebrae and irregular contours and geometry of the spinal elements have influenced the rapid development of more precise imaging modalities. Various advancements to two- and three-dimensional imaging through plain radiographs, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and EOS imaging along with multiple dimensional views of the spine are continuously optimized. Future developments in imaging may improve the assessment of pedicle screw placement and image definition, reduce radiation, and provide autonomous spinal mapping using artificial intelligence.

Magnetic resonance imaging (MRI) is a critical tool for evaluating the normal and pathologic states of the spine and associated tissues. Advancements in MRI technology have greatly improved visualization of vertebral anatomy and identification of pathologic abnormalities, including spinal stenosis, degenerative disc disease, tumors, ligamentous abnormalities, and more. In addition to eliminating exposure to harmful radiation, MRI offers superior depiction of soft tissues relative to plain radiography and computed tomography. However, its potential to highlight clinically insignificant abnormalities requires correlation with patient history and clinical exam findings when determining diagnosis and guiding surgical decision-making. This chapter focuses on the efficacy of various MRI imaging sequences in evaluating vertebral anatomy and identifying various pathologic presentations within the cervical spine.

STUDY DESIGN:Survey. OBJECTIVE:In March of 2020, an original study by Louie et al investigated the impact of COVID-19 on 902 spine surgeons internationally. Since then, due to varying government responses and public health initiatives to the pandemic, individual countries and regions of the world have been affected differently. Therefore, this follow-up study aimed to assess how the COVID-19 impact on spine surgeons has changed 1 year later. METHODS:A repeat, multi-dimensional, 90-item survey written in English was distributed to spine surgeons worldwide via email to the AO Spine membership who agreed to receive surveys. Questions were categorized into the following domains: demographics, COVID-19 observations, preparedness, personal impact, patient care, and future perceptions. RESULTS:Basic respondent demographics, such as gender, age, home demographics, medical comorbidities, practice type, and years since training completion, were similar to those of the original 2020 survey. Significant differences between groups included reasons for COVID testing, opinions of media coverage, hospital unemployment, likelihood to be performing elective surgery, percentage of cases cancelled, percentage of personal income, sick leave, personal time allocation, stress coping mechanisms, and the belief that future guidelines were needed (P<.05). CONCLUSION:Compared to baseline results collected at the beginning of the COVID-19 pandemic in 2020, significant differences in various domains related to COVID-19 perceptions, hospital preparedness, practice impact, personal impact, and future perceptions have developed. Follow-up assessment of spine surgeons has further indicated that telemedicine and virtual education are mainstays. Such findings may help to inform and manage expectations and responses to any future outbreaks.

Anterior cervical discectomy and fusion (ACDF) is a common surgical treatment for degenerative disease in the cervical spine. However, resultant biomechanical alterations may predispose to early-onset adjacent segment degeneration (EO-ASD), which may become symptomatic and require reoperation. This study aimed to develop and validate a machine learning (ML) model to predict EO-ASD following ACDF. Retrospective review of prospectively collected data of patients undergoing ACDF at a quaternary referral medical center was performed. Patients > 18 years of age with > 6 months of follow-up and complete pre- and postoperative X-ray and MRI imaging were included. An ML-based algorithm was developed to predict EO-ASD based on preoperative demographic, clinical, and radiographic parameters, and model performance was evaluated according to discrimination and overall performance. In total, 366 ACDF patients were included (50.8% male, mean age 51.4 ± 11.1 years). Over 18.7 ± 20.9 months of follow-up, 97 (26.5%) patients developed EO-ASD. The model demonstrated good discrimination and overall performance according to precision (EO-ASD: 0.70, non-ASD: 0.88), recall (EO-ASD: 0.73, non-ASD: 0.87), accuracy (0.82), F1-score (0.79), Brier score (0.203), and AUC (0.794), with C4/C5 posterior disc bulge, C4/C5 anterior disc bulge, C6 posterior superior osteophyte, presence of osteophytes, and C6/C7 anterior disc bulge identified as the most important predictive features. Through an ML approach, the model identified risk factors and predicted development of EO-ASD following ACDF with good discrimination and overall performance. By addressing the shortcomings of traditional statistics, ML techniques can support discovery, clinical decision-making, and precision-based spine care.

This study describes a novel, combined Modic changes (MC) and structural endplate abnormality phenotype of the cervical spine, which we have termed the Modic-Endplate-Complex (MEC), and its association with preoperative symptoms and outcomes in anterior cervical discectomy and fusion (ACDF) patients. This was a retrospective study of prospectively collected data at a single institution. Preoperative cervical magnetic resonance imagings were used to assess the presence of MC and endplate abnormalities. Patients were divided into four groups: MC-only, endplate abnormality-only, the MEC and controls. The MEC was defined as the presence of both a MC and endplate abnormality in the cervical spine. Phenotypes were further stratified by location and compared to controls. Associations with patient-reported outcome measures were assessed using regression controlling for baseline characteristics. A total of 628 patients were included, with 84 MC-only, 166 endplate abnormality-only, and 187 MEC patients. Both MC (p < 0.001) and endplate abnormalities (p < 0.001) were independently associated with one another. MC at the adjacent level (p = 0.018), endplate abnormalities (regardless of location) (p = 0.001), and the MEC within the fusion segment (p = 0.027) were all associated with higher Neck Disability Index scores. Both MC within the fusion segment (p = 0.008) and endplate abnormalities within the fusion segment (p = 0.017) associated with lower Veteran's Rand 12-item scores. MC and structural endplate abnormalities commonly manifest concomitantly in patients indicated for ACDF for degenerative pathology. Patients with the endplate pathology, including the MEC phenotype, reported significantly higher levels of postoperative disability following ACDF. These findings add valuable data to the prognostic assessment of degenerative cervical spine patients.

The subaxial cervical spine refers to cervical vertebrae located below the "axis" (C2) and is a critical distinction due to inherent biomechanical differences from vertebral levels more cephalad and caudad (Swartz et al., 2005). Responsible for the majority of cervical range of motion, vertebrae ranging from C3 to C7 contribute roughly 70 of flexion, 40 of extension, 30 of lateral bending, and 45 of rotation to either side (Tan et al., 2017). Furthermore, in the native cervical spine, C3–C7 (specifically, the facet joints) is responsible for about two-thirds of the total axial load imposed by the cranium. The remaining load is then distributed among cervical intervertebral discs (Tan et al., 2017). These relationships are held in a close equilibrium that is ultimately dependent upon a precise sagittal alignment, where the global cervical lordosis (i.e., C2–C7 curvature), sagittal vertical axis (SVA), T1 slope (T1S), and various other radiographic parameters cohesively interact (Jun et al., 2015; Park et al., 2013). However, in the setting of various pathologies, these biomechanical relationships are frequently disrupted, often resulting in a redistribution of axial loading and diminished capacity to maintain native range of motion (Tan et al., 2017). Ultimately, these findings stress the importance of making appropriate radiographic measurements in the cervical spine, as the magnitude of radiographic disturbance is associated with disease prognosis and may help guide surgical management. As such, the present chapter will discuss the importance of critical subaxial radiographic measures, with particular emphasis placed on the clinical relevance and technique required to accurately perform these assessments.

This chapter examines the various classification schemes utilized to categorize alignment, assess boney anomalies, and assess disc vitality to identify potential lumbosacral disease and injury. Spinal pathophysiology is often multifactorial. On occasions, the severity of pathology and treatment is clear. In other instances, the pathology is more nuanced, requiring additional clinical and radiographic assessments. These cases have led to the development of multiple imaging-based classification systems in an attempt to identify which patients will respond appropriately to a specific intervention. An understanding of the classification schemes currently utilized is invaluable as it further solidifies their clinical significance and continues to drive research forward.

Background: The prevalence of back pain in the pediatric population is increasing, and the workup of these patients presents a clinical challenge. Many cases are selflimited, but failure to diagnose a pathology that requires clinical intervention can carry severe repercussions. Magnetic resonance imaging (MRI) carries a high cost to the patient and health care system, and may even require procedural sedation in the pediatric population. The aim of this study was to develop a scoring system based on pediatric patient factors to help determine when an MRI will change clinical management. Methods: This is a retrospective cohort analysis of consecutive pediatric patients who presented to clinic with a chief complaint of back pain between 2010 and 2018 at single orthopaedic surgery practice. Comprehensive demographic and presentation variables were collected. A predictive model of factors that influence whether MRI results in a change in management was then generated using cross-validation least absolute shrinkage and selection operator logistic regression analysis. Results: A total of 729 patients were included, with a mean age of 15.1 years (range: 3 to 20 y). Of these, 344 (47.2%) had an MRI. A predictive model was generated, with nocturnal symptoms (5 points), neurological deficit (10 points), age (0.7 points per year), lumbar pain (2 points), sudden onset of pain (3.25 points), and leg pain (3.75 points) identified as significant predictors. A combined score of greater than 9.5 points for a given patient is highly suggestive that an MRI will result in a change in clinical management (specificity: 0.93; positive predictive value: 0.92). Conclusions: A predictive model was generated to help determine when ordering an MRI may result in a change in clinical management for workup of back pain in the pediatric population. The main factors included the presence of a neurological deficit, nocturnal symptoms, sudden onset, leg pain, lumbar pain, and age. Care providers can use these findings to better determine if and when an MRI might be appropriate. Level of Evidence: Level III—diagnostic study.