title: A stereotactic near-infrared probe for localization during functional neurosurgical procedures: further experience.
abstract: OBJECTIVE
  The authors previously developed an optical stereotactic probe employing near-infrared (NIR) spectroscopy to provide intraoperative localization by distinguishing gray matter from white matter. In the current study they extend and further validate this technology.
  
  
  METHODS
  Near-infrared probes were inserted 203 times during 138 procedures for movement disorders. Detailed validation with postoperative imaging was obtained for 121 of these procedures and with microelectrode recording (MER) for 30 procedures. Probes were constructed to interrogate tissue perpendicular to the probe path and to incorporate hollow channels for microelectrodes, deep brain stimulation (DBS) electrodes, and other payloads.
  
  
  RESULTS
  The NIR data were highly correlated to imaging and MER recordings for thalamic targets. The NIR data were highly sensitive but less specific relative to imaging for subthalamic targets, confirming the ability to detect the subthalamic nucleus and to provide warnings of inaccurate localization. The difference between the NIR- and MER-detected midpoints of the subthalamic nucleus along the chosen tracks was 1.1 +/- 1.2 mm (SD). Data obtained during insertion and withdrawal of the NIR probe suggested that DBS electrodes may push their targets ahead of their paths. There was one symptomatic morbidity. Detailed NIR data could be obtained from a 7-cm track in less than 10 minutes.
  
  
  CONCLUSIONS
  The NIR probe is a straightforward, quick, and robust tool for intraoperative localization during functional neurosurgery. Potential future applications include localization of targets for epilepsy and psychiatric disorders, and incorporation of NIR guidance into probes designed to convey various payloads.
authors.affiliation: Baylor Radiosurgery Center, Baylor University Medical Center, Dallas, TX 75246, USA. ColeG@BaylorHealth.edu
authors.forename: Cole A
authors.initials: CA
authors.lastname: Giller
authors.forename: Hanli
authors.initials: H
authors.lastname: Liu
authors.forename: Dwight C
authors.initials: DC
authors.lastname: German
authors.forename: Dheerendra
authors.initials: D
authors.lastname: Kashyap
authors.forename: Richard B
authors.initials: RB
authors.lastname: Dewey
mesh_terms: D001931:Brain Mapping / Q000295:instrumentation; D046690:Deep Brain Stimulation / Q000295:instrumentation*; D004292:Dominance, Cerebral / Q000502:physiology; D004421:Dystonia / Q000503:physiopathology / Q000628:therapy*; D004867:Equipment Design; D020329:Essential Tremor / Q000503:physiopathology / Q000628:therapy*; D005917:Globus Pallidus / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008839:Microelectrodes; D008866:Microsurgery / Q000295:instrumentation*; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy*; D011183:Postoperative Complications / Q000175:diagnosis / Q000473:pathology; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation*; D013238:Stereotaxic Techniques / Q000295:instrumentation*; D020531:Subthalamic Nucleus / Q000473:pathology / Q000503:physiopathology; D013525:Surgical Instruments; D013788:Thalamus / Q000473:pathology / Q000503:physiopathology; D014057:Tomography, X-Ray Computed; D014202:Tremor / Q000503:physiopathology / Q000628:therapy*