Frameless stereotaxy with scalp-applied fiducial markers for brain biopsy procedures: experience in 218 cases

Object. The goal of this study was to develop and assess the use and limita tions of performing brain biopsy procedures by using image-guided surgical navigation systems (SNSs; that is, frameless stereotactic systems) with sca lp-applied fiducial markers. Methods. Two hundred eighteen percutaneous brain biopsies were performed in 213 patients by using a frameless stereotactic SNS that operated with eith er sonic or optical digitizer technology and scalp-applied fiducial markers for the purpose of registering image space with operating room space. Comm on neurosurgical and stereotactic instrumentation was adapted for use with a localizing wand, and recently developed target and trajectory guidance so ftware was used. Eight (3.7%) of the 218 biopsy specimens were nondiagnostic; five of these (2.4%) were obtained during procedures in 208 supratentorial lesions and th ree were obtained during procedures in 10 infratentorial lesions (30%; p < 0.001). Complications related to the biopsy procedure occurred in eight pat ients (seven of whom had supratentorial lesions and one of whom had an infr atentorial lesion, p > 0.25). Five complications were intracerebral hemorrh ages (two of which required craniotomy), two were infections, and one was w ound breakdown after instillation of intratumoral carmustine following biop sy. There were only three cases of sustained morbidity, and there were two deaths and one delayed deterioration due to disease progression. Two surgeons performed the majority of the procedures (193 cases). The thre e surgeons who performed more than 10 biopsies had complication rates lower than 5%, whereas two of the remaining four surgeons had complication rates greater than 10% (p = 0.15). Twenty-three additional procedures were performed in conjunction with the b iopsies: nine brachytherapies; five computer-assisted endoscopies; four cys t aspirations; two instillations of carmustine; two placements of Ommaya re servoirs; and one craniotomy. Conclusions. Brain biopsy procedures in which guidance is provided by a fra meless stereotactic SNS with scalp-applied fiducial markers represents a sa fe and effective alternative to frame-based stereotactic procedures for sup ratentorial lesions. There were comparable low rates of morbidity and a hig h degree of diagnostic success. Strategies for performing posterior fossa b iopsies are suggested.