OBJECT: Anterior decompression and stabilization for thoracic spinal tumors often involves a thoracotomy and can be associated with surgical approach-related complications. An alternative to thoracotomy is surgery via a costotransversectomy exposure. To delineate the risks of surgery, the authors reviewed their prospective database for patients who had undergone surgery via either of these approaches for thoracic or thoracolumbar tumors. The complications were recorded and graded based on severity and risk of impact on patient outcome. METHODS: Between September 1995 and April 2001, the authors performed 29 costotransversectomies (Group 1) and 18 thoracolumbar or combined (Group 2) approaches as initial operations for thoracic neoplasms. The age, sex, preoperative motor score, and preoperative Frankel grade did not significantly differ between the groups. In the costotransversectomy group there were greater numbers of metastases, upper thoracic procedures, and affected vertebral levels; additionally, the comorbidity rate based on Charlson score, was higher. The mean Frankel grades at discharge were not significantly different whereas the discharge motor and last follow-up motor scores were better in Group 2. There were 11 Group 1 and seven Group 2 patients who suffered at least one complication. The number or patients with complications, the mean number of complications, and severity of complications did not differ between the groups. CONCLUSIONS: Compared with anterior or combined approaches, the incidence and severity of perioperative complications in the surgical treatment of thoracic and thoracolumbar spinal tumors is similar in patients who undergo costotransversectomy. Costotransversectomy may be the preferred operation in patients with significant medical comorbidity or tumors involving more than one thoracic vertebra.