Article

This study aimed to confirm the location and degree of compromise of
the subclavian vessels within the thoracic outlet during ipsilateral arm
abduction in patients with clinical evidence of thoracic outlet syndrome and to
identify both the physical and physiologic source of neurovascular compromise
that induces the symptoms of thoracic outlet syndrome. DESIGN: After a
neuromuscular and vascular examination, all of the subjects underwent a two-part
high-resolution computed tomographic angiography with three-dimensional
reformation. The initial study was performed with the arm held at the side in an
anatomical neutral position. Subsequently, the arm was abducted to 90 degrees
with external rotation (ABER). In each position, 60 ml of iodinated nonionic
contrast medium was injected in the opposite arm at 4 ml/sec. Three-dimensional
volume-rendered images were obtained. Each image was subsequently reviewed by a
musculoskeletal radiologist (S. Yadavalli). Patients were initially evaluated in
the physiatrist's private office (M.M. LaBan). The computed tomographic scans
were obtained from the participants as outpatients in an academic community-based
medical center (William Beaumont Hospital). Seventeen outpatients with clinical
signs and symptoms of thoracic outlet syndrome were evaluated, including seven
men and ten women.
This group has an average age of 48 yrs (range, 17-73 yrs).
RESULTS: The level of vessel occlusion varied in the costoclavicular space as
well as in demonstrating the alterations in the diameter of both the subclavian
artery and vein both in the neutral and ABER positions.
The possible levels of
occlusions included the costoclavicular space, the interscalene triangle, and the
retropectoralis minor space.
The narrowing of the subclavian vessel was
considered significant if the percentage change of the vessel's diameter between
the neutral and the ABER positions was 30% or greater for the subclavian artery
and 50% or greater for the subclavian vein. CONCLUSIONS: The average change in
the costoclavicular space between the neutral and ABER positions was 18.2 mm or
55.6%. The degree of subclavian artery occlusion was significant in 8 (47%) of
the 17 patients. The average change in artery diameter was 28% (5.5 to 7.5 mm).
Significant subclavian vein occlusion was present in 12 (75%) of 16 patients. The
average change in venous diameter was 54.1% (5.7 to 12.6 mm). In two cases,
venous occlusion occurred in the retropectoralis minor space, one of which was
significant at 79%. The vast majority of patients, that is, 13 (76.5%) of 17,
demonstrated a compression of either the subclavian vein or artery, whereas 6
(35.3%) of 17 demonstrated a compression in both. In each of these cases, the
asymptomatic side failed to demonstrate a significant change in either the venous
and/or arterial caliber.

Langue : ANGLAIS