Communicating uncertainty in evidence-to-decision translation in NASS Guidelines
Authors: Ahmad Ozair, MD, MPH1, Piyush Kalakoti, MD2, Peter Passias, MD3, Waeel Hamouda, MD, FRCS, PhD4,David B. Anderson, PhD6, Cumhur Kilincer, MD, PhD7, William Dillin, MD8, on Behalf of North American Spine Society (NASS) Clinical Practice Guidelines Committee
1. Montreal Neurological Institute and Hospital; and Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
2. Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
3. Department of Orthopedic Surgery, Duke University School of Medicine, Durham, NC, United States
4. Department of Neurosurgery, Cairo University, Cairo, Egypt
5. Department of Neurosurgery, Security Forces Hospital, Dammam, Saudi Arabia
6. Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
7. Department of Neurosurgery, Trakya University Faculty of Medicine, Edirne, Türkiye
8. Independent Spine Evaluation Inc., Dallas, TX, United States
Background
Hippocrates had remarked, in Aphorisms (400 BC): ‘Those diseases which medicines do not cure, the knife cures; those which iron cannot cure, fire cures; and those which fire cannot cure, are to be reckoned wholly incurable.’
While we now widely recognise that quite a few of Hippocrates’ management approaches were limited by the science of the day, what is now also obvious is the great conviction or certainty in the remark. This certainty becomes humbling in hindsight, given that many of the treatments of an age have frequently found to have been either futile or harmful in later ages. Thus, in current clinical practice and scientific reporting, a major thrust is on appropriately communicating the gaps in knowledge and the uncertainty in the body of evidence.
The entanglement of biomedical evidence and clinical decision-making has been long-standing. In the modern framework of evidence-based medicine (EBM) that comprises of best available evidence + clinical expertise + patient preferences, as introduced by Sackett, Guyatt and others, each aspect of diagnosis and treatment has an underlying evidence base. This evidence base (while recognised in many cases to still be insufficient!) is evolving and expanding each day. However, not only that – it is being synthesised and reappraised regularly by professional medical and regulatory organisations, with accompanying changes in the assessment of the uncertainty in the body of evidence that informs recommendations. Other paradigms of evidence-based healthcare, such as the JBI model, share these attributes.
For the 2024 Evidence-Based Health Care (EBHC) Day, we had described the history, evolution and growing impact of spine-related evidence appraisal, systematic reviewing efforts and guideline development. This effort falls under the aegis of the North American Spine Society (NASS), which served as an ‘EBHC 2024 evidence ambassador’. Continuing the themes of spine-related ‘evidence synthesis’ and ‘evidence transfer’ for the 2025 EBHC day, we examine the relevant aspects of communicating uncertainty in spine-related evidence to decision translation and dissemination, in context of experiences and perspectives of some of the members of the NASS Clinical Practice Guidelines (CPGs) committee.
The vexing problems in spine evidence generation, synthesis and transfer
Spine disorders are complex and represent biologically heterogeneous conditions, with a diversity of potential and overlapping issues. In the past, this has made it hard to conduct strictly controlled, randomised studies in homogenous patient populations. Substantial heterogeneity exists not only in the study populations, but also in the myriad preferred treatment strategies across different healthcare providers and schools of training (with significant geographical influence).
Patients and clinicians (particularly those in training as well as those specialists yet to finalise a preferred approach per condition) face an ever-growing toolbox of strategies. These can be mixed and matched to allow for a dizzying variety of interventions possible for a given spine condition. As such, considerable practice variation in spine care exists, which has been thought to result in inconsistent care (such as suboptimal patient selection for spine fusion) and major disparities in outcomes.
EBM follows an approach of delivering optimal care that is aligned with patient preferences and clinical expertise, grounded in the best available evidence base. As such, it has been a long-standing effort to tackle the heterogeneity and the disparities in the outcomes discussed above. The initial solution in EBM was envisioned that each clinician would be trained to evaluate the medical literature themselves. However, given the rapidly increasing number of spine-related papers, busy clinicians frequently find it challenging to incorporate regular daily appraisal of the literature, as well as synthesise evidence from conflicting papers. Thus, despite abundant research, a growing body of evidence remains to reach clinicians or patients in a clearly usable form. Evidence often remains siloed within disciplines and journals, particularly with the evolving nature of closed and open access nature of publication.
Spine evidence synthesis and NASS Guidelines
Efforts have long been ongoing in spine care to tackle this pressing issue, initially through the development of decision-making algorithms and later, clinical guidelines.
Richard Rothman and colleagues had been some of the earliest to develop spine decision-making algorithms to organise the management approach to low back pain and lumbar spine, cervical spine and repeat surgery. As we review these influential algorithms several decades later, quite obvious again is the firmness and lack of uncertainty in the wording of these spine care algorithms, even though the evidence base supporting some of the decision forks would be deemed quite weak today.
Spine care guidelines also emerged—initially, like all guidelines—in the GOBSAT model: ‘Good Old Boys Sat Around a Table.’ A need remained for evidence-based guidelines led by a specialty society in spine surgery.
NASS, established through the merger of the North American Lumbar Spine Association and the American College of Spinal Surgeons in 1985, emerged as a multidisciplinary organisation. It includes orthopaedic surgery, neurological surgery, physiatry, pain management, biomechanical and basic science research as well as other disciplines. Its aim is to jointly advance spine care through education, research and advocacy. As described previously, NASS guidelines appraise, evaluate and synthesise the evidence to provide a recommendation on specific interventions related to spinal conditions. Major completed guideline efforts pertain to degenerative lumbar spinal stenosis, low back pain, adult isthmic spondylolisthesis, lumbar disc herniation with radiculopathy, degenerative cervical radiculopathy, antibiotic prophylaxis in spine surgery, osteoporotic vertebral compression fractures and neoplastic vertebral fractures, with the most recent, soon-to-be-completed NASS guidelines, on diagnosis and treatment of sacroiliac joint pain.
Communicating uncertainty in evidence synthesis and evidence transfer
Given the evolving nature of biomedicine, and in particular, the evidence base for spine-related diagnosis and treatment, a critical aspect is the recognition of uncertainty. All clinicians, including spine care experts, are susceptible to the same biases. These include confirmation, selection, anchoring and recency bias when evaluating the medical literature. Therefore, communication of underlying uncertainty and, if possible, potential delineation of specific gaps, is critical for both evidence synthesis and evidence transfer.
These biases affect not only clinicians, but guideline panel members as well. Hidden biases affect the development of guidelines. Therefore, a system is needed to address biases in a structured fashion. The NASS Diagnosis and Treatment of Adults with Sacroiliac Joint Pain are the first NASS guidelines fully based on the GRADE approach. This structured methodology allows for a comprehensive and standardised assessment and transparent reporting of the certainty of the body of evidence.
Briefly, the use of the GRADE Evidence-to-Decision (EtD) framework provides guideline developers with a systematic structure to translate evidence into recommendations, balancing desirable and undesirable effects, values, acceptability and feasibility. Confidence in a given recommendation is explicitly tied to the quality of evidence (high, moderate, low, or very low), which helps clinicians interpret the strength and applicability of the recommendation in practice.
The inclusion of multidisciplinary panels and stakeholders ensures a broader and more balanced appraisal of evidence, as well as more grounded wording of the writing overall. The writing of the guideline is greatly influenced by the incorporation of patient perspectives through dedicated patient representatives. This has been meaningful in areas where treatment choices may be preference-sensitive.
Communicating the uncertainty in practical, clinician-facing terms allows practitioners to contextualise evidence limitations at the point of care (e.g. ‘evidence suggests some potential benefit, but certainty is low, therefore shared decision-making is recommended’). All of this gets refined by multiple rounds of feedback and review from external societies and other independent stakeholders, which enhances credibility and reduces perception of insularity.
Unfortunately, due to a limited number of high-quality randomised controlled trials, there are many interventions which have uncertain effectiveness, resulting in limited or no recommendations. The fact remains that patients will still seek treatment from clinicians, so without guidance, clinicians are no better placed to make clinical decisions. How should NASS therefore best communicate uncertainty in a way that guides clinical decision-making, while also reflecting the current evidence? To address this problem, NASS implemented the appropriate use criteria (AUC) approach, distinct from its CPG. There have been two recent major outputs so far: (1) OVCF Appropriate Use Criteria (AUCs) and (2) NVCF AUC. These have been disseminated widely via NASS website, The Spine Journal and other media. These scenario-based AUCs have been found to be valued by clinicians.
Lessons learnt and challenges encountered
Several challenges, already well recognised, of meaningfully pursuing EBM were faced by the NASS CPG Committee. These include achieving consensus statements and clinical recommendations that are applicable to institutions across a broad range of regions, institutional variation and cultural variations. There is also an inherent delay in the development of the evidence-based recommendations, due mostly to the time it takes to derive high-level and meaningful studies that can be gathered into high quality recommendations. Interpreting the available data is also lengthy, although technological advances such as large-language models have reduced the time for some of the steps (such as study screening).
The GRADE process itself is also resource-intensive, requiring detailed assessments of bias, inconsistency and indirectness. In a rapidly evolving field like spine surgery—where new technologies and techniques are continually introduced—there is a risk that these guidelines will become outdated quickly. Thus, living guidelines are potentially the next step.
Finally, even for areas where the guidelines do not provide recommendations, by systematically mapping the areas where evidence is weak, inconsistent, or completely absent, the guidelines direct future research towards the most pressing clinical questions. This makes the research enterprise more cost-effective, ensuring that limited resources are invested in studies with the greatest potential to reduce uncertainty and improve patient outcomes.
Next steps
Opportunities on the horizon include broadening partnerships beyond specialty societies to engage global professional organisations, patient advocacy groups and allied health providers. This will ensure wider dissemination and relevance of guidelines. Emerging technologies such as AI-powered literature summaries, interactive digital platforms and multilingual formats offer new pathways to make evidence more accessible across diverse settings and better communicating uncertainty all along. Strengthening feedback loops with patients, clinicians and other stakeholders can help ensure that recommendations remain aligned with evolving patient preferences and clinical expertise. The creation of modular digital guideline repositories, including pilot decision-support tools powered by large language models, may represent another practical step toward embedding evidence at the point of care (while feasibly communicating uncertainty). Finally, sharing lessons learnt in guideline development and dissemination globally may foster dialogue and collaboration across evidence-based health care communities, particularly in regions where guideline infrastructure is still developing.
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To link to this article - DOI: https://doi.org/10.70253/AIFY5690
Links to additional resources
View NASS’ published and in-progress Clinical Practice Guidelines here: https://www.spine.org/guidelines
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