Faculty Bibliography

STUDY DESIGN/METHODS:Delphi Consensus. OBJECTIVE:To define an optimal surgical composite outcome measure in patients with metastatic spine disease (OSCO-M) through international consensus among key opinion leaders. METHODS:Members of the AO Spine Knowledge Forum Tumor, an international group of dedicated spine oncology surgeons and oncologists, participated in a modified Delphi process between March 2023 and November 2024. The study was conducted in two parts. The first part aimed on identifying which outcome variables were deemed important to be included in the composite outcome. The second part focused on the definition of a successful outcome with regards to the agreed variables from Part 1. Each part consisted of a questionnaire and a consensus meeting. Consensus was achieved when a threshold of 70% agreement was reached. RESULTS:A total of 42 dedicated spine oncology surgeons and oncologists from North America, Latin America, Europe, and Asia participated. Over 87% of respondents agreed that composite measures reflect the multidimensional aspect of the surgical process more than an individual outcome variable. Most respondents (93%) agreed/strongly agreed that composite measures should be used to assess the quality of surgical care in spine oncology. Through consensus, the following three outcome variables were selected to define the OSCO-M: the absence of SAVES-V2 (Spinal Adverse Events Severity System, Version 2) Grade 3 adverse events or higher within 30 days of surgery, maintaining or improving ECOG (Eastern Cooperative Oncology Group) performance status at 90 days, and being ambulatory (with or without aid) at 90 days. CONCLUSION/CONCLUSIONS:This is the first study defining a composite outcome measure in oncologic surgery for spinal metastases derived from an international group of key opinion leaders in spine oncology. The OSCO-M may be useful for future research in spine tumor patients and serve as a benchmark to optimize outcomes.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Bone metastases, affecting more than 4.8% of patients with cancer annually, and particularly spinal metastases require urgent intervention to prevent neurological complications. However, the current process of manually reviewing radiological reports leads to potential delays in specialist referrals. We hypothesized that natural language processing (NLP) review of routine radiology reports could automate the referral process for timely multidisciplinary care of spinal metastases. METHODS:We assessed 3 NLP models-a rule-based regular expression (RegEx) model, GPT-4, and a specialized Bidirectional Encoder Representations from Transformers (BERT) model (NYUTron)-for automated detection and referral of bone metastases. Study inclusion criteria targeted patients with active cancer diagnoses who underwent advanced imaging (computed tomography, MRI, or positron emission tomography) without previous specialist referral. We defined 2 separate tasks: task of identifying clinically significant bone metastatic terms (lexical detection), and identifying cases needing a specialist follow-up (clinical referral). Models were developed using 3754 hand-labeled advanced imaging studies in 2 phases: phase 1 focused on spine metastases, and phase 2 generalized to bone metastases. Standard McRae's line performance metrics were evaluated and compared across all stages and tasks. RESULTS:In the lexical detection, a simple RegEx achieved the highest performance (sensitivity 98.4%, specificity 97.6%, F1 = 0.965), followed by NYUTron (sensitivity 96.8%, specificity 89.9%, and F1 = 0.787). For the clinical referral task, RegEx also demonstrated superior performance (sensitivity 92.3%, specificity 87.5%, and F1 = 0.936), followed by a fine-tuned NYUTron model (sensitivity 90.0%, specificity 66.7%, and F1 = 0.750). CONCLUSION/CONCLUSIONS:An NLP-based automated referral system can accurately identify patients with bone metastases requiring specialist evaluation. A simple RegEx model excels in syntax-based identification and expert-informed rule generation for efficient referral patient recommendation in comparison with advanced NLP models. This system could significantly reduce missed follow-ups and enhance timely intervention for patients with bone metastases.

Study DesignLiterature review with clinical recommendations.ObjectiveSpinal metastases represent a late complication of cancer and a major factor in decreased quality of life. The role of surgery for specific indications for spinal metastases is well established. Given the significant morbidity associated with spine surgery in this frail population, efforts are ongoing to decrease the surgical footprint. The objective of this study is to provide the readers with a concise curation of the latest spine literature on reducing the surgical footprint for spine metastases and clinical recommendations for how the practicing clinician should interpret and make use of this evidence.MethodsThe latest spine literature in the topic of reducing the surgical footprint for spine metastases was reviewed and clinical recommendations were formulated. The recommendations are dichotomously graded into strong and conditional based on the integration of scientific methodology and content expert opinion. This opinion considers experience and practical issues such as risks, burdens, costs, patient values, and circumstances.ResultsFour high impact studies were selected for review. The findings suggest that surgery plays a key role in improving patients' quality of life, but incidence of adverse events remains high and hence methods to decrease surgical morbidity are necessary. The integration of radiation into the treatment algorithm allows for less extensive surgical procedures and SBRT should be strongly considered after surgery for spine metastases in appropriate patient populations. Implementation of enhanced recovery after surgery (ERAS) protocols reduce perioperative morbidity for both open and minimally invasive surgeries and should be considered on an institutional level. Utilization of minimally invasive surgical stabilization should be considered as it results in fewer post operative complications, lower infection rates, less blood loss during surgery, and a shorter hospital stay compared to open stabilization of unstable pathology thoracolumbar fractures.ConclusionsThe role and benefits of surgery for metastatic spine disease are well established, yet surgery carries significant risk for adverse events which may negatively affect overall cancer care. Methods for reducing the surgical footprint include incorporation of stereotactic radiation allowing less extensive surgery, implementation of ERAS protocols and utilization of minimally invasive surgical strategies.

BACKGROUND/OBJECTIVES/OBJECTIVE:Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive malignancies with a challenging prognosis, especially for patients with Neurofibromatosis type 1 (NF1). Their low incidence necessitates comprehensive studies to investigate the survival outcome. METHODS:We conducted a systematic review and meta-analysis, including data from 16 studies and 4265 patients, to explore surgical outcomes and survival rates, focusing on time-related outcomes, including overall survival (OS), progression-free survival (PFS), and recurrence rate. RESULTS:The analysis revealed that the OS rate was 86% [95% CI: 75-97%] at 1 year, decreasing to 60% [95% CI: 45-75%] at 3 years, and further declining to 47% [95% CI: 35-58%] by 5 years. For PFS, the 1-year rate was 61% [95% CI: 25-98%], which remained similar at 62% [95% CI: 35-89%] for 3 and 5 years. In NF1-associated MPNSTs, the 1-year OS was relatively high at 93% [95% CI: 83-100%], but it dropped to 68% [95% CI: 53-84%] at 3 years and further to 50% [95% CI: 31-68%] at 5 years. Additionally, the hazard ratio indicated a 38% lower survival rate in NF1 patients than those with sporadic MPNSTs when data were presented in the same study. Recurrence rates were high, with 56% of patients experiencing a relapse, primarily as local recurrences (70.6%). Mortality was significant, with over 50% of patients dying within an average follow-up period of 33.45 months. CONCLUSIONS:MPNSTs, particularly in NF1 patients, are associated with poor prognosis and high recurrence rates. These results underline the necessity of targeted therapeutic strategies and improved programs for screening, mainly through a multidisciplinary approach to optimize management.

Study DesignBibliometric analysis.ObjectivesThis study used bibliometric analyses to characterize the effect of AO Spine Knowledge Forum (KF) participation on publication trends among members. We examined associations of membership in KF organizations with academic productivity, collaboration, and scientific impact.MethodsWe queried the Web of Science database for publications by members of KF Tumor (N = 58), KF Trauma and Infection (N = 45), KF Spinal Cord Injury (N = 38), KF Degenerative (N = 54), and KF Deformity (N = 55). Resulting metadata were exported; statistical and bibliometric analyses were performed using Python packages.ResultsOur query returned 24,267 articles by KF members, of which 18,804 were identified as relevant to respective organizational themes through an algorithmic analysis of titles and abstracts. These works, published between 1980 and 2025, included contributions from 67,895 authors. Research productivity, co-authorship among members (P < 0.001), unique institutional affiliations per article (P < 0.001), and international collaboration increased contemporaneously with the first KF formation (2010). A positive association was found between the number of KF authors per publication and source journal impact factor (P < 0.001). Term analysis highlighted research foci within each KF and influential publications were identified.ConclusionsThese findings suggest that formalization of researcher relationships and the research infrastructure and support provided by the KF model was associated with increased and more impactful research output and collaboration. The KF model could be applied in other organizations whose mission includes collaborative research. Methods used in this study are easily replicable and may be applied to investigate the impact of other professional organizations across various fields.

The AO Spine Knowledge Forums are independent expert-driven global study groups dedicated to improving patient care by publishing evidence-based recommendations and conducting high-impact clinical studies. Five Knowledge Forums represent 6 spine pathologies: tumor, deformity, spinal cord injury, degeneration, trauma, and infection. A summary highlighting their most impactful research achievements over the past 10 years is provided. The results illustrate the critical clinical role of these independent Knowledge Forums.

Study DesignThis study is part of the AO Spine Metastatic Tumor Research and Outcomes Network [MTRON], an international multicenter prospective observational registry including patients with spinal metastases.ObjectivesThis study aims to elucidate the incidence of surgical complications, their risk factors and consequent effects on survival outcomes, hospital length of stay, and overall health-related quality of life (HRQOL) parameters in a large cohort of patients affected by spinal metastases who were surgically treated.MethodsAvailable data from February 2017 to July 2023 were analyzed. The primary outcome of this study was the evaluation of the incidence of intraoperative and postoperative adverse events (AEs). The secondary outcomes included the assessment of risk factors for surgery-related AEs and the impact of AEs on survival, length of hospital stay and quality of life.ResultsAmong the 1267 patients analyzed, 6.9% experienced intraoperative AEs and 19.3% experienced at least 1 postoperative AE. Several factors resulted to be associated to the occurrence of postoperative AEs: age, smoking habit, poor Eastern Cooperative Oncology Group (ECOG) Performance status, previous radiation therapy at the index target, duration of surgery, number of instrumented levels, simultaneous anterior and posterior approach, presence of metastases at other sites, multiple spinal metastases. Postoperative AEs were associated with reduced survival rates, increased hospital length of stay and poorer HRQOL outcomes, particularly in domains such as neurological function and mental health. In general, surgery substantially improves HRQOL across multiple domains, with these benefits persisting over time despite the occurrence of AEs. However, patients with preoperative risk factors, including comorbidities, smoking, neurological impairment, and prior radiation therapy, experienced less improvement.ConclusionsThe negative impact of AEs on overall survival and HRQOL could be associated with the presence of some preoperative parameters of frailty that are detected as risk factors for AEs occurrence. This finding emphasizes the need for personalized preoperative assessments and optimized perioperative care strategies.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Dural arteriovenous fistula (dAVF) surgery is a microsurgical procedure that requires confirmation of obliteration using formal cerebral angiography, but the lack of intraoperative angiogram or need for postoperative angiogram in some settings necessitates a search for alternative, less invasive methods to verify surgical success. This study evaluates the use of indocyanine green videoangiography FLOW 800 hemodynamic intraoperatively during cranial and spinal dAVF obliteration to confirm obliteration and predict surgical success. METHODS:A retrospective analysis was conducted using indocyanine green videoangiography FLOW 800 to intraoperatively measure 4 hemodynamic parameters-Delay Time, Speed, Time to Peak, and Rise Time-across venous drainage regions of interest pre/post-dAVF obliteration. Univariate and multivariate statistical analyses to evaluate and visualize presurgical vs postsurgical state hemodynamic changes included nonparametric statistical tests, logistic regression, and Bayesian analysis. RESULTS:A total of 14 venous drainage regions of interest from 8 patients who had successful spinal or cranial dAVF obliteration confirmed with intraoperative digital subtraction angiography were extracted. Significant hemodynamic changes were observed after dAVF obliteration, with median Speed decreasing from 13.5 to 5.5 s-1 (P = .029) and Delay Time increasing from 2.07 to 7.86 s (P = .020). Bayesian logistic regression identified Delay Time as the strongest predictor of postsurgical state, with a 50% increase associated with 2.16 times higher odds of achieving obliteration (odds ratio = 4.59, 95% highest density interval: 1.07-19.95). Speed exhibited a trend toward a negative association with postsurgical state (odds ratio = 0.62, 95% highest density interval: 0.26-1.42). Receiver operating characteristic-area under the curve analysis using logistic regression demonstrated a score of 0.760, highlighting Delay Time and Speed as key features distinguishing preobliteration and postobliteration states. CONCLUSION/CONCLUSIONS:Our findings demonstrate that intraoperative FLOW 800 analysis reliably quantifies and visualizes immediate hemodynamic changes consistent with dAVF obliteration. Speed and Delay Time emerged as key indicators of surgical success, highlighting the potential of FLOW 800 as a noninvasive adjunct to traditional imaging techniques for confirming dAVF obliteration intraoperatively.

OBJECTIVE:Surgery is typically indicated for mechanical pain in metastatic spine disease or severe neurological compromise, but how radicular pain responds to oncological treatment is not well described. The primary aim of this study was to describe how radicular pain responds to oncological treatment, while secondary aims included pain outcomes between patients with mechanical and tumoral pain and motor improvement in patients with weakness due to nerve root compression. METHODS:Patients treated with surgery and/or radiotherapy for spinal metastases were identified from an international multicenter prospective cohort. The primary outcome was the numeric rating scale (NRS) score for pain at 3 months posttreatment. Motor recovery from radicular compression in patients with myotomic weakness and low-grade epidural compression was also analyzed. RESULTS:Of 284 patients, 129 (45%) had radicular pain ± axial pain and 155 (55%) had axial pain alone. The two groups did not significantly differ in age, comorbidities, tumor characteristics, or treatment. Two hundred two patients (71%) underwent surgery ± radiotherapy, whereas 82 (29%) had radiotherapy alone. The NRS score of patients with radicular pain improved from 6.7 to 3.4 at 3 months, a statistically significantly higher magnitude than in patients with isolated axial pain (p = 0.021). The NRS score at 3 months was similar for both groups (p = 0.876). Patients with radicular pain experienced a larger improvement with surgery compared with radiotherapy alone (p = 0.007) but had higher pretreatment pain (mean NRS score 7.0 vs 5.6, p = 0.013). Twenty-three patients identified with radicular/myotomic weakness (mean American Spinal Injury Association score 96.3 ± 3.2) at baseline improved 2.1 ± 3.8 points at 3 months. CONCLUSIONS:The magnitude of pain improvement for patients with radicular pain following surgery and radiotherapy for metastatic spine disease is higher than for patients with axial pain alone. Surgery is associated with a larger improvement in radicular pain than radiotherapy alone. These results will allow clinicians to tailor treatment options for patients with metastatic spine disease.

Study DesignLiterature review with clinical recommendation.ObjectiveTo provide the readers with a concise curation of the latest literature in recent advances in systemic oncological therapies and their implications for decision-making in patients with metastatic spinal disease. This review aims to enhance spine specialist's understanding of modern oncological treatments to facilitate optimal timing and planning of local interventions.MethodsThe latest literature in the topic of advances in oncology was reviewed by a multidisciplinary group of experts in metastatic spinal disease and clinical recommendations were formulated. The recommendations were dichotomously graded into strong and conditional (weak) based on the integration of scientific methodology and content expert opinion. This opinion considered experience and practical issues such as risks, burdens, costs, patient values, and circumstances.ResultsFour high-impact studies were reviewed, demonstrating significant advancements in systemic treatments for metastatic cancers commonly affecting the spine. These studies showed improved survival outcomes and efficacy across breast cancer, colorectal cancer, prostate cancer, and renal cell carcinoma. The findings have important implications for surgical/radiotherapy planning, including considerations for timing of interventions, wound healing, and the potential for extended survival affecting construct durability requirements.ConclusionsRecent advances in systemic oncological treatments have important implications for managing metastatic spinal disease. Understanding these developments is crucial for spine specialists to optimize decision-making through a multidisciplinary approach, particularly regarding timing of local interventions, strategy of the surgical approach and reconstruction.[Formula: see text].