Clinical validation of true frameless stereotactic biopsy: Analysis of the first 125 consecutive cases

OBJECTIVE: A lockable guide device, adjustable for positioning, was used to obtain samples for tissue analysis during brain biopsy procedures performed using an interactive image guidance system. Clinical validation of this technique, which was developed for true frameless stereotactic biopsies, and analyses of the histological yield, complication rate, and patient demographic characteristics for a large series of frameless stereotactic biopsies were the purposes of this study. METHODS: Demographic, radiological, surgical, and clinical data were prospectively collected for a series of 125 frameless stereotactic biopsies performed using the technique described in detail previously. RESULTS: Eighty-six procedures were magnetic resonance imaging-directed and 39 were computed tomography-directed. The mean diameter of the biopsied lesions was 36 mm, and the mean distance from the skin was 35.8 mm. Sixteen percent of the patients harbored multiple lesions, and 5.6% of the biopsied lesions were infratentorial. The mean operative time (including the entire anesthetic time) was 1.5 hours. The smear examination findings were corroborated by conclusive histological results in 96% of the cases, and definitive positive diagnoses were obtained in 122 cases (97.6%). Ten patients experienced surgical complications, but the sustained morbidity rate was 2.4% (including the death of a patient who was in critical clinical condition preoperatively and who died 2 mo later as a result of a chest infection; mortality rate, 0.8%). CONCLUSION: This true frameless stereotactic biopsy technique was associated with low morbidity and mortality rates and an excellent diagnostic yield, with overall results at least as good as those observed for frame-based stereotaxy. The excellent accuracy results demonstrated previously and statistically significant reductions in operative time, as well as improved image presentation, target selection, and simplicity, support the use of this frameless stereotactic technique in preference to frame-based biopsy techniques.