Recent developments focus on a minimal-invasive approach to the thoracic spine with thoracoscopy. Very often it is necessary to collapse the lung in order to expose the thoracic spine. This technique cannot be used on patients with reduced pulmonary capacity or pleural adhesions. We are trying to use a semi- open technique to combine the advantages of open and thoracoscopic surgery. The semi-open technique requires a 5 cm incision over the 10th rib with or without partial removal of the rib and retropleural approach to the thoracolumbar spine. From this incision a retropleural insertion of the thoracoscope using an additional incision 2 ribs above the original incision can be performed if necessary. The vertebra and surrounding tissues are visualised by thoracoscope, all further necessary interventions as well as diaphragm splitting can be performed via the main approach. After trial operations on cadavers we performed a spondylodesis on 22 patients with fractures of the lower thoracic and upper lumbar spine using a semi-open technique. With the above described incision we were able to expose all vertebrae from Th11 to L2 and to perform a splitting of the diaphragm. Two cases needed an intraoperative and one case a postoperative pleural drainage. The maximum blood loss was 200 ml, maximum operation time 180 min. No complications such as infections or malunion occurred during follow-up. We conclude that the semi-open technique is combining the advantage of open and thoracoscopic surgery avoiding a collapse of the lung and reducing the number of pleural drainages. All levels of the thoracolumbar spine can be reached and a safe spondylodesis with minimal blood loss can be performed. However this technique is requiring a learning curve and should be preceded by animal or cadaver trial operations.