Objective: Radiation necrosis is a well-known complication of radiotherapy for malignant brain tumors. Although surgery was once considered the mainstay of treatment, no recent reports have evaluated the use of intraoperative magnetic resonance imaging (IOMRI) and frameless stereotaxis during surgical resection of radiation necrosis. In this retrospective review, we evaluate the effectiveness of surgical resection using frameless stereotaxis and IOMRI for the treatment of radiation necrosis.
Methods: From October 1999 through February 2002, 11 patients who had malignant brain tumors underwent surgery for radiation necrosis. The diagnosis of radiation necrosis was based primarily on MRI and clinical suspicion. Frameless stereotaxis was used in all patients and IOMRI was used in nine. All patients underwent at least one radiation treatment before surgery and nine patients had multiple treatments. Patient outcome was based on changes in steroid dose, Karnofsky Performance Score (KPS), and neurologic deficit.
Results: Optimal resection as confirmed by IOMRI was achieved in all patients by the use of frameless stereotaxis alone; no additional resection was performed in any patient. For nine patients taking steroids (mean preoperative dose 24 mg/day) before treatment of necrosis, all had a substantial reduction in steroid dosage (mean postoperative dose 8 mg/day) after surgical treatment. Postoperatively, KPS improved in four patients, remained stable in four, and worsened in three. Three complications that resulted from surgery included wound infection, asymptomatic carotid dissection, and pulmonary embolism; thus, overall morbidity including both surgical complications and neurologic deterioration was 54%.
Conclusions: In this review, frameless stereotaxis was helpful in guiding the surgeon; however, IOMRI did not provide any additional benefit for the surgical treatment of radiation necrosis. Surgical treatment of radiation necrosis was associated with high risks of complication or neurologic deficit. Given the success of medical therapies, including hyperbaric oxygen, we believe that surgical treatment of radiation necrosis should be reserved for symptomatic patients in whom medical therapy has failed.