Use of sonography in thoracic outlet syndrome due to a dystonic pectoralis minor.
OBJECTIVE
For patients with thoracic outlet syndrome (TOS), it is important to determine the location of the neurovascular compression to achieve effective intervention.


METHODS
The diagnostic workup for a 39-year-old man with TOS included a selective anesthetic block of the pectoralis minor muscle and duplex sonography before and after the block.


RESULTS
The subclavian artery peak systolic flow velocity decreased after the block from 208 to 63 cm/s when the arm was in the abduction and external rotation position, indicating a reduction in the severity of focal arterial compression. Also, the arterial diameter increased by 10% after the block (from 0.80 to 0.88 cm). His level of discomfort was reduced from 6 to 2 on a scale of 1 to 10 (66%).


CONCLUSIONS
The pectoralis minor block resulted in an improvement in subclavian artery blood flow and symptoms and confirmed the diagnosis of pectoralis minor TOS. This suggests that selective anesthetic muscle blocks and duplex sonographic studies may be useful before chemodenervation and surgery.
Odderson
Ib R
IR
Department of Rehabilitation Medicine, University of Washington Medical Center, Seattle, 98195, USA. odderson@u.washington.edu
Chun
Edward S
ES
Kolokythas
Orpheus
O
Zierler
R Eugene
RE
D000328:Adult; D004421:Dystonia / Q000150:complications* / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D009407:Nerve Block / Q000379:methods*; D010369:Pectoralis Muscles / Q000000981:diagnostic imaging*; D013901:Thoracic Outlet Syndrome / Q000000981:diagnostic imaging* / Q000209:etiology*; D014463:Ultrasonography