Evaluating ambulatory function as an outcome following treatment for spinal metastases: a systematic review

Abstract

Background context: Studies regarding treatment of spinal metastases are critical to evidence-based decision-making. However, variation exists in how a key outcome, ambulatory function, is assessed.

Purpose: To characterize the sources and tools investigators have used to evaluate ambulatory function as an outcome following treatment of spinal metastases. We also sought to understand the ways ambulatory function has been conceptualized in prior studies.

Study design: Systematic review of the literature.

Patient sample: We identified 44 published studies for inclusion. Samples within these investigations ranged from 20 to 2,096 subjects.

Outcome measures: We describe the methods investigators have used to evaluate ambulatory function following treatment for spinal metastases.

Methods: We conducted a systematic review through PubMed, Scopus and Web of Science following PRISMA guidelines. We included studies that consisted of adult patients receiving operative or non-operative treatment for spinal metastases. We also required that study investigators specified post-treatment ambulatory function as an outcome. We recorded year of publication, study design, types of spinal metastases included in the study, treatments employed, and sample size. We also described the source (medical record, study-specific observer and/or provider, patient and/or participant), tool (standardized measure, quantitative, qualitative) and concept (eg, ambulatory vs. non-ambulatory; independent ambulation vs. ambulatory with assistance vs. non-ambulatory) used to assess ambulatory function.

Results: We found the plurality of studies relied on medical record documentation as their source. Amongst prospective studies, only a minority used a quantitative measure (eg, prespecified degree of walking ability) to assess ambulatory function. Most studies conceptualized ambulatory function as a dichotomized outcome, typically ambulatory versus non-ambulatory or a similar equivalent.

Conclusions: Wide variation exists in how ambulatory function is defined in studies involving patients with spinal metastases. We suggest several improvements that will allow a more robust assessment of the quality and quantity of ambulatory function among patients treated for spinal metastases.

Keywords: Ambulatory function; Decision-making; Non-operative treatment; Spinal metastases; Surgery; Systematic review.