[Substernal goiter: diagnostic and therapeutic problems (apropos of a personal series of 585 interventions)].

This retrospective study is based on a personal experience of 585 operations performed between 1958 and 1993. The diagnosis and topographic evaluation of the thoracic extension of a goiter were greatly improved by the development of the new imaging technics (CT Scan and RMN). Those rather expansive and complex technics were not necessary in 505 cases (86.3%), the diagnosis and topographic evaluation being easy from the conventional tests (X-ray, echography, scintigraphy). But in 80 cas (13.7%) either the diagnosis or the topographic evaluation were difficult or mistaken because Scan or RMN were not yet available or were not used (20 thoracic extensions overlooked; 26 separated thoracic goiters; 24 crossed thoracic extensions; 5 massive degeneration of thoracic extension; 5 false thoracic extension simulated by a mediastinal tumor). The surgical ablation of the substernal goiter could be achieved through a simple cervical approach in 96.4% of the operations. In 21 cases it appeared necessary to prolong the cervicomy by a median sternotomy (total and extrapleural sternotomy in all cases). The transternal approach was imposed in 9 cases by a profound and voluminous thoracic extension in contrast with a small cervical thyroid. In 5 cases, the reason was a massive malignant degeneration of the thoracic extension. In 7 patients the operation was done for a mediastinal redux after a previous cervical thyroidectomy having overlooked the thoracic extension. In spite of all the difficulties, all operations were successful with no mortality and a low morbidity (although slightly higher than the overall morbidity of thyroid surgery).