Reliability and exploration of the side-lying thoraco-lumbar rotation measurement (strm).

Study design: Clinical Measurement, Reliability, Descriptive Study

Objectives: To establish intrarater and interrater reliability of the Side-lying Thoraco-lumbar Rotation Measurement (STRM) and to explore frequencies and magnitude of rotational differences that exist in various musculoskeletal conditions.

Background: Limitation in thoracic rotation could lead to increased motion at adjacent areas (i.e., shoulders and low back). This could potentially lead to excessive strain and subsequent injury from repetitive stress. Currently, there is no well-established method to reliably measure and objectively quantify thoraco-lumbar spine rotation.

Methods: Intrarater reliability was assessed by a single investigator performing three STRM measurements on 10 participants on two consecutive days. Interrater reliability was assessed by two independent examiners, performing the STRM on 30 participants. Reliability was assessed using the intraclass correlation coefficient (ICC) statistic. To explore the incidence and magnitude of side-to-side thoraco-lumbar rotation differences, the STRM was measured on 156 participants of various musculoskeletal conditions.

Results: The intrarater reliability of the STRM was excellent (ICC=.94). The interrater reliability was good (ICC=.88). Fifty four percent of the sample exhibited greater than a 10% side-to-side difference in the STRM while twenty percent exhibited greater than a 20% side-to-side difference.

Conclusion: The STRM can be used as a reliable and objective method to quantify thoraco-lumbar spine rotation. It also appears that a large percentage of patients with varied musculoskeletal complaints may have greater than a 10-20% asymmetry in spinal rotational movement. Future research is needed to determine the clinical applicability and relevance of these findings.

Level of evidence: 4.