Quantitative dynamic wearable motion-based metric compared to patient-reported outcomes as indicators of functional recovery after lumbar fusion surgery.

BACKGROUND: Low back pain is a debilitating condition with poor patient outcomes despite the use of a wide variety of diagnostic and treatment modalities. A lack of objective metrics to support clinical decision-making may be a reason for these poor outcomes. This study aimed to compare patient recovery following lumbar fusion surgery using an objective motion-based metric (functional performance) and subjective patient-reported outcomes for pain, disability and kinesophobia.

METHODS: A prospective observational study was conducted on 121 patients that received a lumbar fusion surgery. A wearable motion system was used to quantify three-dimensional multi-planar lumbar motion and benchmark each patient's lumbar function prior to surgery and post-operatively at follow-up time points for up to 2 years. Patient recovery profiles after surgery were evaluated using the acquired functional motion data and compared to patient-reported outcomes.

FINDINGS: Our results found significant improvement after surgery in objective functional performance as well as patient-reported pain, disability, and kinesophobia. However, we found a delayed response in the objective metric, with meaningful improvement occurring only 6 months after fusion surgery. In contrast, we found significant improvement in all subjective scores as early as 6 weeks post-surgery.

INTERPRETATION: Objective motion-based metric provides a unique perspective to assessing patient's functional recovery. While it is associated with dimensions of pain, disability and fear avoidance, it is also distinct and assesses a uniquely different dimension of functional health. This information can form the basis for the use of objective metrics to gauge patient recovery after lumbar fusion surgery.