Faculty Bibliography

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.

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.

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].

Study DesignNarrative Review.ObjectivesTo summarize the work of the AO Spine Knowledge Forum Tumor, specifically studies from the Epidemiology, Process and Outcomes in Spine Oncology (EPOSO) study.MethodsA narrative review of all published manuscripts from the EPOSO study was undertaken. EPOSO represents a multicenter, prospective registry effort across 10 North American and European sites to enroll patients with metastatic disease of the spine.ResultsThe current review summarized all studies from the EPOSO network, divided into the following five sections: (1) quality of life and satisfaction, (2) overall survival, (3) spinal instability, (4) neurologic outcome in patients with metastatic epidural spinal cord compression or radicular pain, and (5) patient and tumor-specific factors. Several important findings were elucidated. Patient evaluation should include SINS, nutritional status, severity and duration of neurologic deficit, extent of metastatic tumor burden, and differentiation of axial from radicular pain. Moreover, SOSGOQ2.0 serves as a useful and validated instrument for patient-reported outcome instrument. Despite the palliative nature of metastatic spine surgery, clear improvement in quality-of-life is seen. Even in patients with short-survival, the remaining weeks and months of life result in improved quality-of-life. Metastatic spine surgery often improves neurologic function, potentially enhancing survival through increased performance status.ConclusionsSeveral noteworthy results have come from the EPOSO network, highlighting important trends in metastatic spine care. The AO Spine Knowledge Forum Tumor has helped advancing metastatic spine tumor research as well as ensure these new findings reach and benefit clinicians and their patients.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Aggressive resection for primary tumors of the spine are associated with a high rate of adverse events (AEs), but the impact of AEs on patient-reported outcomes (PROs) remains unknown and is critical to the shared decision-making. Our primary objective was to assess the impact of surgical AEs on PROs using an international registry. Assessing the impact on clinical outcomes and identifying risk factors for AEs were our secondary objectives. METHODS:Patients who underwent surgery for a primary spinal tumor were selected through the Primary Tumor Research and Outcomes Network. Our primary outcome was the impact of AEs on PROs at 3 and 12 months after surgery (measured with Spinal Oncology Study Group Outcomes Questionnaire, Short-Form 36, and EuroQol 5 Dimension). We also assessed the impact on clinical outcomes (local control, surgical margins, readmission, reoperation, and mortality). We stratified our results according to severity of AEs, histology, and type of resection. RESULTS:374 patients met inclusion criteria (219 males/155 females). The mean age of the cohort was 48.7 years. The most frequent histology was chordoma (37.3%) followed by chondrosarcoma (8.8%). Sixty-seven patients (17.9%) experienced at least 1 intraoperative AE and 117 patients (31.3%) had at least 1 postoperative AE within 3 months. Overall, 159 patients (42.5%) experienced AEs. The readmission rate was significantly higher in patients who experienced AEs (Any AE: 10.1% vs no AE: 1.9% within 3 months; P = <0.001). PROs were not significantly affected by AEs in most questionnaires. Local control, risk of reoperation, mortality, and achieving preplanned margins were similar between AE groups. CONCLUSION/CONCLUSIONS:The rate of surgical AEs is considerable in this population. Surgical AEs seem to be associated with a higher number of readmissions, but do not seem to result in significant differences in PROs or in a higher risk of reoperation, mortality, and failure to achieve preplanned margins.

STUDY DESIGN/METHODS:cross-sectional survey. OBJECTIVES/OBJECTIVE:To evaluate AO Spine members' practices and comfort in managing metastatic and primary spine tumors, explore the use of decision-support and patient assessment tools, and identify knowledge gaps and future needs in spine oncology. METHODS:An online survey was distributed to AO Spine members to query comfort levels with key decisions in spinal oncology management, utilization of decision frameworks and spine oncology-specific instruments, and educational material preferences. RESULTS:Responses were obtained from 381 members across 82 countries. Most respondents were orthopedic spine surgeons (62%) or neurosurgeons (36%), with 42% performing 100-200 spine surgeries per year. Extradural primary and metastatic tumors were managed by 84% and 95% of respondents, respectively, with survival and frailty assessment tools used for both. While most surgeons felt comfortable determining when emergency surgery was needed (81% for primary and 82% for metastatic tumors), nuanced decisions about surgical timing were more challenging. Surgeons also noted challenges in tailoring the oncologic surgical plan to what the patient could safely tolerate. There was a strong desire for guidelines on tumor-related spinal pain (85%), treatment timing (85%), stabilization (85%), and glucocorticoid use for symptomatic extradural metastatic tumors (77%). Interest was high for classification systems for spine tumor pain (65%) and stabilization decisions (80%). CONCLUSIONS:Additional support is needed in decision-making regarding surgical timing, patient selection, and tailoring treatment invasiveness to life expectancy and frailty. Surgeons seek further guidance to prevent neurologic deterioration and optimize recovery. Guidelines and classification systems were highly coveted for daily practice.

STUDY DESIGN/METHODS:Scoping review. OBJECTIVE:To identify which markers are used as surrogates for malnutrition in metastatic spine disease and which are the most studied outcomes associated with it. METHODS:A scoping review was performed by searching the PubMed/Medline, EMBASE, and Web of Science databases up to July 2022. We searched for articles exploring markers of malnutrition in spine oncology patients including but not limited to albumin, body weight, weight loss, and nutrition indices. A narrative synthesis was performed. RESULTS:A total of 61 articles reporting on 31,385 patients met inclusion criteria. There were 13 different surrogate markers of nutrition, with the most common being albumin in 67% of studies (n = 41), body weight/BMI in 34% (n = 21), and muscle mass in 28% (n = 17). The most common studied outcomes were survival in 82% (n = 50), complications in 28% (n = 17), and length of stay in 10% (n = 6) of studies. Quality of life and functional outcomes were assessed in 2% (n = 1) and 3% (n = 2) of studies, respectively. Out of 61 studies, 18% (n = 11) found no association between the examined markers and outcome. CONCLUSION/CONCLUSIONS:Assessment of nutritional status in patients with spinal metastases is fundamental. However, there is lack of a comprehensive and consistent way of assessing malnutrition in oncologic spine patients and therefore inconsistency in its relationship with outcomes. A consensus agreement on the assessment and definition of malnutrition in spine tumor patients is needed.