Faculty Bibliography

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.

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:Systematic review and clinimetric analysis. OBJECTIVES/OBJECTIVE:Frailty and sarcopenia predict worse surgical outcomes among spinal degenerative and deformity-related populations; this association is less clear in the context of spinal oncology. Here, we sought to identify frailty and sarcopenia tools applied in spinal oncology and appraise their clinimetric properties. METHODS:, 2000, until June 2022. Study characteristics, frailty tools, and measures of sarcopenia were recorded. Component domains, individual items, cut-off values, and measurement techniques were collected. Clinimetric assessment was performed according to Consensus-based Standards for Health Measurement Instruments. RESULTS:). Frailty and sarcopenia measures lacked or had uncertain content and construct validity. Frailty measures were objective except the Johns-Hopkins Adjusted Clinical Groups. All tools were feasible except the Hospital Frailty Risk Score (HFRS). Positive predictive validity was observed for the HFRS and in select studies employing the mFI-5, MSTFI, and L3-TPA/VBA. All frailty tools had floor or ceiling effects. CONCLUSIONS:Existing tools for evaluating frailty and sarcopenia among patients undergoing surgery for spinal tumors have poor clinimetric properties. Here, we provide a pragmatic approach to utilizing existing frailty and sarcopenia tools, until more clinimetrically robust instruments are developed.

STUDY DESIGN/METHODS:Narrative Review. OBJECTIVE:Contextualized by a narrative review of recent literature, we propose a wound complication prevention and management algorithm for spinal oncology patients. We highlight available strategies and motivate future research to identify optimal and individualized wound management for this population. METHODS:We conducted a search of recent studies (2010-2022) using relevant keywords to identify primary literature in support of current strategies for wound complication prevention and management following spine tumor surgery. When primary literature specific to spine tumor cases was not available, data were extrapolated from studies of other spine surgery populations. Results were compiled into a proposed clinical algorithm to guide practice considering available evidence. RESULTS:Based on available literature, we recommend individualized stratification of patients according to identifiable risk factors for wound complication and propose several interventions which might be employed preventatively, including intrawound antibiotic administration, negative pressure wound therapy, and primary flap closure of the surgical wound. Of these, the available evidence, weighing possible risks vs benefits, most strongly favors primary flap closure of surgical wounds, particularly for patients with multiple risk factors. A secondary algorithm to guide management of wound complications is also proposed. CONCLUSIONS:Wound complications such as SSI and dehiscence remain a significant source of morbidity following spine tumor surgery. Triaging patients on an individualized basis according to risk factors for complication may aid in selecting appropriate prophylactic strategies to prevent these complications. Future research in this area is still needed to strengthen recommendations.

STUDY DESIGN/METHODS:Narrative review of existing literature. OBJECTIVES/OBJECTIVE:Significant technological advancements in radiotherapy planning and delivery have enabled new radiotherapy techniques for the management of spine tumors. The objective of this study was to provide a comprehensive summary of these treatment techniques for practicing spine surgeons. METHODS:A narrative review of the existing literature on stereotactic body radiation therapy (SBRT) and particle beam therapy (PBT) for the treatment of spine tumors was performed. The characteristics, implementation and evidence supporting these strategies in the management of primary spinal neoplasms were summarized. RESULTS:The clinical effectiveness of SBRT for the control and symptom palliation of metastatic spinal tumors are well demonstrated in multiple clinical trials. Risks such as fracture, radiculopathy and plexopathy exist after spine SBRT, necessitating an individualized approach in a well experienced multidisciplinary setting. SBRT should be considered a key component of a well-rounded treatment plan for metastatic spine tumors in combination with surgery, vertebral augmentation, and drug therapy, where indicated, to achieve optimal patient outcomes. Additionally, PBT and SBRT are also leading to promising results for primary spine tumors, though comparative effectiveness studies and prospective clinical trials are required to establish these modalities more formally as alternatives to conventionally fractionated photon radiotherapy. CONCLUSIONS:SBRT and PBT are emerging as effective and well tolerated treatment options for primary and metastatic spine tumors. Additional investigation is needed to personalize these treatment options and further strengthen these approaches as key components in a multidisciplinary approach to the management of spinal neoplasms.

STUDY DESIGN/METHODS:Systematic Review. OBJECTIVES/OBJECTIVE:Formalized terminology for pain experienced by spine cancer patients is lacking. The common descriptors of spine cancer pain as mechanical or non-mechanical is not exhaustive. Misdiagnosed spinal pain may lead to ineffective treatment recommendations for cancer patients. METHODS:We conducted a systematic review of pain terminology that may be relevant to spinal oncology patients. We provide a comprehensive and unbiased summary of the existing evidence, not limited to the spine surgery literature, and subsequently consolidate these data into a practical, clinically relevant nomenclature for spine oncologists. RESULTS:Our literature search identified 3515 unique citations. Through title and abstract screening, 3407 citations were excluded, resulting in 54 full-text citations for review. Pain in cancer patients is typically described as nociceptive pain (somatic vs visceral), neurologic pain and treatment related pain. CONCLUSIONS:We consolidate the terminology used in the literature and consolidated into clinically relevant nomenclature of biologic tumor pain, mechanical pain, radicular pain, neuropathic pain, and treatment related pain. This review helps standardize terminology for cancer-related pain which may help clinicians identify pain generators.