Technique of supraclavicular decompression for neurogenic thoracic outlet syndrome.

The supraclavicular approach to scalenectomy and first rib resection has been modified since the original description in 1985. The incision is 1 to 2 cm above the clavicle, 1 cm lateral to the midline, and 5 to 7 cm long. Subplatysmal skin flaps are created. The sternocleidomastoid muscle is mobilized on its lateral edge and retracted but not divided. The scalene fat pad is split vertically, the omohyoid muscle excised, and the C5 nerve root dissected free. The accessory phrenic nerve is identified, if present, arising medially from C5, and preserved. The rest of the plexus is dissected free, muscular and connective tissue removed from all nerve roots and trunks, and the subclavian artery identified. The phrenic nerve is identified on the medial edge of the anterior scalene muscle (ASM). The ASM is divided on the first rib. The ASM is elevated, freed, and divided as high as possible and free of C5. The middle scalene muscle is dissected. C5 and C6 branches of the long thoracic nerve are identified and protected as the portion of middle scalene muscle adjacent to the nerves of the plexus is excised. The decision on whether the first rib is to be removed is determined by whether the lower trunk of the plexus is touching the first rib. If the rib is removed, its posterior end is freed, divided, and 1 cm excised. The rest of the rib is freed from the intercostal muscles with a periosteal elevator or harmonic scalpel, the pleura is separated from the inner surface of the rib, and the anterior end divided with an infraclavicular rib cutter. The operation has been made safer by identifying and dissecting the C5 nerve root before looking for the phrenic nerve.