OBJECTIVE: This is a prospective study to evaluate the indications and outcome of the hemiclamshell incision (longitudinal partial sternotomy combined with an antero-lateral thoracotomy) as used for a consecutive series of patients requiring surgery for various thoracic pathologies not ideally approached by postero-lateral thoracotomy, sternotomy or thoracoscopy. METHODS: All patients with a hemiclamshell incision performed between 1994 and 1998 were prospectively analyzed regarding indications, postoperative morbidity and outcome (clinical examination and pulmonary function testing) in order to validate this incision for thoracic surgery. RESULTS: 25 patients (15 men, 10 women) with an age ranging from 16 to 73 years (mean 43 years) underwent a hemiclamshell incision. The indications for the hemiclamshell approach were (1) chest trauma with massive hemorrhage requiring urgent access to the mediastinum and the ipsilateral pleural space (40%), (2) tumors of the anterior cervico-thoracic junction with suspicion of vascular involvement (28%) and (3) lesions involving both one chest cavity and the mediastinum (32%). The 30-day mortality was 8%. One patient suffered a sternal wound infection, mediastinitis and pleural empyema after a gun shot wound, whereas wound healing was uneventful in all other patients. Analgesic requirements for postoperative pain relief were not increased as compared to those following a standard thoracotomy. At 3 months normal sensitivity of the entire chest wall and intact shoulder girdle function was noted in 90% of the patients. Pulmonary function testing showed no restriction due to the hemiclamshell incision. CONCLUSIONS: The hemiclamshell incision is a useful approach in selected patients and does not cause more morbidity or long-term sequelae than a standard thoracotomy.