title: Image-guided frameless stereotactic needle biopsy in awake patients without the use of rigid head fixation.
abstract: OBJECTIVE
  Image-guided frameless stereotactic techniques provide an alternative to traditional head-frame fixation in the performance of fine-needle biopsies. However, these techniques still require rigid head fixation, usually in the form of a head holder. The authors report on a series of fine-needle biopsies and brain abscess aspirations in which a frameless technique was used with a patient's head supported on a horseshoe headholder. To validate this technique, they performed an in vitro accuracy study.
  
  
  METHODS
  Forty-eight patients underwent fine-needle biopsy of intracranial lesions that ranged in size from 0.9 to more than 107.7 ml; a fiducial-less, frameless, image-guided technique was used without rigid head fixation. In 1 of the 48 patients a cerebral abscess was drained. The accuracy study was performed with a skull phantom that was imaged with a CT scanner and tracked with a registration mask containing light-emitting diodes. The objective was a skin fiducial marker with a 4-mm circular target to accommodate the 2.5-mm biopsy needle. A series of 50 trials was conducted.
  
  
  RESULTS
  Diagnostic tissue was obtained on the first attempt in 47 of 48 brain biopsy cases. In 2 cases small hemorrhages at the biopsy site were noted as a complication on the postoperative CT scan. One of these hemorrhages resulted in hand and arm weakness. The accuracy study demonstrated a 98% success rate of the biopsy needle passing through the 4-mm circular target using the registration mask as the registration and tracking device. This demonstrates a ± 0.75-mm tolerance on the targeting method.
  
  
  CONCLUSIONS
  The accuracy study demonstrated the ability of the mask to actively track the target and allow navigation to a 4-mm-diameter circular target with a 98% success rate. The frameless, pinless, fiducial-less technique described herein will likely be another safe, fast alternative to frame-based stereotactic techniques for fine-needle biopsy that avoids the potential morbidity of rigid head-pin fixation. Furthermore, it should lend itself to other image-guided applications such as the placement of ventricular catheters for shunting or Ommaya reservoirs.
authors: Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors: Devin V
authors: DV
authors: Amin
authors: Karl
authors: K
authors: Lozanne
authors: Phillip V
authors: PV
authors: Parry
authors: Johnathan A
authors: JA
authors: Engh
authors: Kathleen
authors: K
authors: Seelman
authors: Arlan
authors: A
authors: Mintz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000295:instrumentation*; D001922:Brain Abscess / Q000473:pathology* / Q000601:surgery; D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging; D004867:Equipment Design; D005260:Female; D057918:Fiducial Markers; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D038361:Neuronavigation / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D012680:Sensitivity and Specificity; D012984:Software; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D055815:Young Adult