Defining spinal instability and methods of classification to optimise care for patients with malignant spinal cord compression: A systematic review

•A lack of guidance on metastatic spinal instability results in variations of care.•Definitions and assessments for spinal instability are explored in this review.•A Spinal Instability Neoplastic Scoring (SINS) system has been identified.•SINS could potentially be adopted to optimise and standardise patient care.

The incidence of Malignant Spinal Cord Compression (MSCC) is thought to be increasing in the UK due to an aging population and improving cancer survivorship. The impact of such a diagnosis requires emergency treatment. In 2008 the National Institute of Clinical Excellence produced guidelines on the management of MSCC which includes a recommendation to assess spinal instability. However, a lack of guidelines to assess spinal instability in oncology patients is widely acknowledged. This can result in variations in the management of care for such patients. A spinal instability assessment can influence optimum patient care (bed rest or encouraged mobilisation) and inform the best definitive treatment modality (surgery or radiotherapy) for an individual patient. The aim of this systematic review is to attempt to identify a consensus definition of spinal instability and methods by which it can be classified.