Current status and challenges in lumbar proprioception measurement: a narrative review.

Lumbar proprioception is the cornerstone for maintaining dynamic spinal stability, postural control, and central sensorimotor regulation. Clinically, proprioceptive deficits are closely tied to the occurrence and recurrence of degenerative lumbar diseases and chronic non-specific low back pain (CLBP). Despite its clinical relevance, objectively and accurately quantifying this metric remains highly controversial methodologically. This review provides a structured overview comparing existing evaluation tools, mapping their technical characteristics and clinical feasibility. To ensure a comprehensive evaluation, a literature search was conducted via PubMed and Web of Science databases utilizing Medical Subject Headings (MeSH) terms related to "lumbar spine" and "proprioception," supplemented by keywords including "motion sense," "vibration sense," and "force sense." Among direct metrics, position sense via inclinometer-based active joint repositioning is most widely applied, whereas motion, force, and vibration senses are less utilized. Within position sense tracking, common clinical tools like dual inclinometry and tape measurement demonstrate weak concurrent validity, large errors, and low test-retest reliability, with absolute reliability further obscured by the lack of a "gold standard." Furthermore, distinct direct metrics (motion threshold, active repositioning, and passive repositioning) lack significant inter-modal correlation. While postural balance offers a more holistic analysis of lumbar function than isolated components, its application remains limited as it is highly susceptible to confounding factors and fails to isolate or directly represent localized peripheral mechanoreceptor proprioception. In conclusion, although a multitude of methodologies have emerged, the inclinometer-based active joint repositioning paradigm demonstrates the highest feasibility in routine clinical practice. However, a universally accepted gold standard remains persistently absent, and objective quantification requires further comprehensive exploration.