Neuronavigation in surgery of intracranial and spinal tumors

Purpose: To demonstrate the new possibilities and advantages of neuronaviga tion in the surgery of intracranial and spinal tumors, based on patient pop ulations treated in our hospital. Materials and methods: An infrared naviga tion system with integrated microscope guidance was used for frameless intr acranial neuronavigation. The biopsies of intracranial tumors were carried out using a frame-based stereotactic technique. Intracranial navigation was , in part, combined with the use of an intraoperative CT scanner and a thre e-dimensional ultrasound system for data acquisition, correction of brain s hifts, and intraoperative quality control. The navigation was also supporte d by presurgical brain mapping with magnetic source imaging. Navigation in spinal surgery was exclusively performed using an infrared navigation syste m in combination with an intraoperative CT scanner. Results: The stereotact ic tumor biopsies (n = 57) were carried out with an accuracy of 91.4% as co mpared with the histological diagnosis. The work flow of stereotactic proce dures could be increased by using the intraoperative CT scanner. Fifty-seve n patients with intracranial tumors were treated with the aid of neuronavig ation between July 1997 and December 1999. These patients showed an improve ment from 80% to 86% on the Karnofsky index 8 weeks postoperatively. The ma jority of intracranial cases were primary brain tumors (n = 30) and metasta ses (n = 13) in functionally important areas of the brain. In four patients , a significant brain shift was observed during neuronavigation, and could be corrected by an image update using either the intraoperative CT scanner (n = 2) or the three-dimensional ultrasound system (n = 2). The presurgical brain mapping with magnetoencephalography was shown to be reliable in the sensory cortex (n = 25). Eleven patients with a thoracic or lumbar tumor we re treated by open surgery or stabilization, using a combination of spinal neuronavigation and the intraoperative CT scanner. Two patients with spinal tumors underwent navigated biopsies. Neither of them showed a reduction in the clinical stage, but the Karnofsky index improved from 63% up to 72% 8 weeks postoperatively. Conclusion: Neuronavigation allows very precise intr acranial and spinal surgery. The problem of brain shift during the navigati on procedures has been solved by intraoperative image acquisition. The use of neuronavigation was shown to improve the postoperative quality of life o f patients suffering from brain and spinal tumors.