Evaluating for a correlation between osteopathic examination and ultrasonography on thoracic spine asymmetry

The thoracic spine is a common area of focus in osteopathic manipulative medicine (OMM) for a variety of conditions. Thoracic spine somatic dysfunction diagnosis is achieved by palpating for asymmetry at the tips of the transverse processes (TPs). Previous studies reveal that instead of following the rule of threes, the TPs of a given thoracic vertebra generally align with the spinous process (SP) of the vertebra above. Ultrasonography has been widely utilized as a diagnostic tool to monitor musculoskeletal conditions; it does not utilize ionizing radiation, and it has comparable results to gold-standard modalities. In the case of thoracic somatic dysfunction, ultrasound (US) can be utilized to determine the location of each vertebral TP and its relationship with the SP. Previous studies have investigated the correlation between OMM and ultrasonography of the cervical, lumbar, and sacral regions. However, there has been no study yet that has compared osteopathic structural examination with ultrasonographic examination of the thoracic vertebral region.

To examine the relationship between osteopathic palpation and ultrasonographic measurements of the thoracic spine by creating a study design that utilizes interexaminer agreement and correlation.

The ClinicalTrials.gov study identifier is NCT04823637. Subjects were student volunteers recruited from the Midwestern University (MWU)-Glendale campus. A nontoxic, nonpermanent marker was utilized to mark bony landmarks on the skin. Two neuromusculoskeletal board-certified physicians (OMM1, OMM2) separately performed structural exams by palpating T2-T5 TPs to determine vertebral rotation. Two sonographers (US1, US2) separately scanned and measured the distance from the tip of the SP to the adjacent TPs of the vertebral segment below. Demographic variables were summarized with mean and standard deviation. Interexaminer agreement was assessed with percent agreement, Cohen's Kappa, and Fleiss' Kappa. Correlation was measured by Spearman's rank correlation coefficient. Recruitment and protocols were approved by the MWU Institutional Review Board (IRB).

US had fair interexaminer agreement for the overall most prominent segmental rotation of the T3-T5 thoracic spine, with Cohen's Kappa at 0.27 (0.09, 0.45), and a total agreement percentage at 51.5%. Osteopathic palpation revealed low interexaminer agreement for the overall most prominent vertebral rotation, with Cohen's Kappa at 0.05 (0.0, 0.27), and 31.8%. Segment-specific vertebral analysis revealed slight agreement between US examiners, with a correlation coefficient of 0.23, whereas all other pairwise comparisons showed low agreement and correlation. At T4, US had slight interexaminer agreement with 0.24 correlation coefficient, and osteopathic palpation showed low interexaminer (OMM1 vs. OMM2) agreement (0.17 correlation coefficient). At T5, there was moderate agreement between the two sonographers with 0.44 (0.27, 0.60) and 63.6%, with a correlation coefficient of 0.57, and slight agreement between OMM1 and OMM2 with 0.12 (0.0, 0.28) and 42.4%, with 0.23 correlation coefficient.

This preliminary study of an asymptomatic population revealed that there is a low-to-moderate interexaminer reliability between sonographers, low-to-slight interexaminer reliability between osteopathic physicians, and low interexaminer reliability between OMM palpatory examination and ultrasonographic evaluation of the thoracic spine.