title: Frameless robotically targeted stereotactic brain biopsy: feasibility, diagnostic yield, and safety.
abstract: OBJECTIVE
  Frameless stereotactic brain biopsy has become an established procedure in many neurosurgical centers worldwide. Robotic modifications of image-guided frameless stereotaxy hold promise for making these procedures safer, more effective, and more efficient. The authors hypothesized that robotic brain biopsy is a safe, accurate procedure, with a high diagnostic yield and a safety profile comparable to other stereotactic biopsy methods.
  
  
  METHODS
  This retrospective study included 41 patients undergoing frameless stereotactic brain biopsy of lesions (mean size 2.9 cm) for diagnostic purposes. All patients underwent image-guided, robotic biopsy in which the SurgiScope system was used in conjunction with scalp fiducial markers and a preoperatively selected target and trajectory. Forty-five procedures, with 50 supratentorial targets selected, were performed.
  
  
  RESULTS
  The mean operative time was 44.6 minutes for the robotic biopsy procedures. This decreased over the second half of the study by 37%, from 54.7 to 34.5 minutes (p < 0.025). The diagnostic yield was 97.8% per procedure, with a second procedure being diagnostic in the single nondiagnostic case. Complications included one transient worsening of a preexisting deficit (2%) and another deficit that was permanent (2%). There were no infections.
  
  
  CONCLUSIONS
  Robotic biopsy involving a preselected target and trajectory is safe, accurate, efficient, and comparable to other procedures employing either frame-based stereotaxy or frameless, nonrobotic stereotaxy. It permits biopsy in all patients, including those with small target lesions. Robotic biopsy planning facilitates careful preoperative study and optimization of needle trajectory to avoid sulcal vessels, bridging veins, and ventricular penetration.
authors.affiliation: Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA.
authors.forename: Kimon
authors.initials: K
authors.lastname: Bekelis
authors.forename: Tarek A
authors.initials: TA
authors.lastname: Radwan
authors.forename: Atman
authors.initials: A
authors.lastname: Desai
authors.forename: David W
authors.initials: DW
authors.lastname: Roberts
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy / Q000379:methods*; D001921:Brain / Q000473:pathology*; D001922:Brain Abscess / Q000175:diagnosis / Q000473:pathology; D001927:Brain Diseases / Q000175:diagnosis* / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology; D004660:Encephalitis / Q000175:diagnosis / Q000473:pathology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D038361:Neuronavigation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D019635:Neurosurgical Procedures / Q000009:adverse effects; D012371:Robotics; D012449:Safety