Background. Recurrence or persistence of neurologic symptoms after sur
gical treatment of patients with thoracic outlet syndrome (TOS) are re
ported to be as high as 25 %. To identify factors affecting the long-t
erm outcome of surgical treatment of patients with TOS, we reviewed ou
r 20-year experience. Methods. One hundred thirty-four transaxillary f
irst rib resections were performed on 118 patients (43 men, 75 women,
mean age 38 +/- 13 years). Eighty-three operations (61.9%) were undert
aken to relieve symptoms resulting from compression of the lower roots
of the brachial plexus, 37 (27.6 %) for compression of both lower and
upper roots, and 14 (10.5 %) for lower root and vascular symptoms. Al
l patients underwent a transaxillary extraperiosteal first rib resecti
on with transection of the scalene muscles. In 73 cases (54.5 %) a res
ection of the anterior scalene muscle was also performed. A cervical r
ib was removed in 28 cases (20.1 %), and anomalous fibrous bands adjac
ent to the neurovascular bundle were resected in 41 cases (30.6 %). Re
sults. No major complications were observed. Of 105 patients (118 proc
edures) followed up (mean follow-up, 99 +/- 72 months), good to excell
ent results were obtained in 96 cases (81.4%) and fair to poor results
were recorded in 22 cases (18.6%). The presence of a long posterior f
irst rib stump, measured from the chest x ray films, was the strongest
determinant of the long-term results among the variables examined (p
< 0.0001). Reoperation, consisting; of neurolysis and resection of the
stump, was performed in 16 patients. The results were excellent in al
l cases at a mean follow-up of 66 +/- 46 months. Primary and secondary
10-year actuarial freedom rates from recurrent symptoms were 80.9 % a
nd 93.1 %, respectively. Conclusions. Our results suggest that the lon
g-term outcome after surger for TOS was strongly influenced by the ext
ent of the first rib resection.