NMM/OMTORIGINAL ARTICLE
Abstract
Context: Thoracic outlet syndrome (TOS) involves the compression of neural or vascular structures in or near the superior thoracic aperture, and osteopathic manipulative treatment (OMT) can be utilized to relieve associated symptoms. Ultrasonography may be useful for determining possible mechanisms by which OMT reduces symptoms, leading to an improved understanding of how to best implement OMT techniques for the treatment of TOS.
Objectives: This study aims to develop a Doppler ultrasonography protocol to assess blood flow changes in the subclavian artery before and after OMT that was intended to address musculoskeletal dysfunction associated with vascular TOS.
Methods: We recruited adults with TOS symptoms and utilized a nonrandomized, crossover design to evaluate blood flow in the subclavian artery before and after OMT utilizing Doppler ultrasonography. Specifically, a fixed-sequence, 2-period crossover design was utilized to compare ultrasound measurements of blood flow at baseline (US1), after a 10-minute rest (US2), and after a physical examination and OMT (US3). The examination, OMT, and ultrasound were performed on both arms, and the participant arms with a positive vascular TOS maneuver were considered TOS-positive. Ultrasound measurements included vessel diameter, peak systolic velocity (PSV), end-diastolic velocity (EDV), and heart rate (HR). Mixed-effect models were utilized to determine the effect of OMT on blood flow, and changes in ultrasound measurements between study time points (US1 vs. US2, US2 vs. US3) and differences by TOS test results and by participant sex were also evaluated.
Results: Fourteen volunteers (6 men, 8 women) participated in the study. Nine (64.3 %) participants had at least 1 arm that was TOS-positive, and 14 (50.0 %) of the 28 arms were TOS-positive. No differences in measurements were found between US1 and US2 (all p≥0.08). When comparing US2 and US3 measurements, vessel diameter (p=0.02) and EDV (p=0.03) increased after OMT. After OMT, HR decreased (p=0.05), and the decrease was greater in TOS-positive arms than in TOS-negative arms (p=0.02). No differences were found between men and women between US1 and US2 (p=0.90) or between US2 and US3 (p=0.16).
Conclusions: These preliminary results suggested that our ultrasonography protocol assessing subclavian artery flow was sensitive to the effects of OMT and identified significantly increased perfusion and decreased HR after OMT. Additionally, our results suggested that TOS-positive arms with compromised vasculature may have greater responsiveness to OMT. Therefore, more rigorous studies are needed to better assess the impact of OMT on TOS and to improve our understanding of the effects of OMT on impaired blood circulation. Such information about OMT would likely benefit patients by identifying effective, low-risk, and noninvasive management options for the treatment of TOS.