Subclavian Vessel Compression Assessed by Duplex Scanning in Patients with Neurogenic Thoracic Outlet Syndrome and No Vascular Signs

Neurogenic thoracic outlet syndrome (NTOS) is the most frequent form of TOS. It may affect both sides, but specific complementary exams are lacking. We aimed to evaluate duplex scanning results in a group of patients with unilateral or bilateral NTOS and no clinical vascular signs, referred for rehabilitation. We performed a retrospective observational study in patients with unilateral or bilateral NTOS and no vascular symptoms. Subclavian vessels were assessed by duplex scanning. Compressions were considered in case of >50% of increased or decreased blood flow. A total of 101 patients met NTOS criteria; mean age was 40 +/- 10.2; 79.2% women. Seventy patients had a unilateral NTOS and 31 a bilateral form. Duplex scanning showed that 56.4% of the patients had vessels compression, 55.7% in the unilateral group and 58.1% in the bilateral (p = 0.81). In unilateral NTOS, 21 (30%) patients had bilateral vascular compression, 17 (24.3%) had ipsilateral compression and 1 (1.4%) had contralateral compression. In bilateral NTOS, 15 (48.4%) had bilateral compression and 3 (9.7%) compression on only one side. We found a significant difference of the rate of vascular compressions between symptomatic and non-symptomatic upper-limbs, 54.5% vs. 32.9%, respectively, (p = 0.002) and a significant association between symptomatic upper-limbs and vascular compression (OR = 2.45 [95%IC: 1.33-4.49]; p = 0.002). The sensitivity and the specificity of the duplex scanning were 54.5% and 67%, respectively. The ROC curve area was of 0.608 [95%IC: 0.527-0.690]. Despite a highly significant association between symptomatic upper-limbs and vascular compression, duplex scanning did not help make the diagnosis of NTOS.