title: Radio-anatomic measurements and statistical generation of a safe surgical corridor to enter the ventricular trigone while avoiding injury to the optic radiations.
abstract: OBJECTIVE
  To find a safe operative corridor to the ventricular trigone avoiding injury to the optic radiations (ORs).
  
  
  METHODS
  In 24 adult hemispheres, dimensions of the atrium, height of the OR, and the cortex-to-atrium distance were measured. Superior parietal lobule (SPL), parieto-occipital sulcus (POS), and middle temporal gyrus (MTG) traced approaches were used to measure maximum safe angles to enter the atrium without traversing the OR. A statistical algorithm was generated using these measurements to predict the height of the OR and safe angles from measurements from MR imaging of five test hemispheres. Statistically calculated angles were compared with measured angles from dissection.
  
  
  RESULTS
  Mean length and height of atrium, height of OR, and cortico-atrium distances were 2.07 cm, 3.36 cm, 2.53 cm, and 4.11 cm, respectively. The height of the atrium influenced the height of the OR significantly (p < 0.0001). The height of the dilated and small atrium was > 4.5 cm (> 95th percentile) and < 2 cm (< 5th percentile), respectively. For the SPL approach, the mean sagittal angle was 15.75 to 41.04 degrees; the mean coronal angle was - 17.08 to 14.92 degrees. For the POS approach, the mean sagittal angle was 51.29 to 70.1 degrees; the mean coronal angle was -8.63 to 17.22 degrees. Mean calculated height (statistically) of the OR was 0.29 mm above the mean observed height (dissection). The calculated angles and observed angles were very similar when tested for a variability of ± 2 degrees.
  
  
  CONCLUSIONS
  The height of the normal atrium was 2.58 cm (height of atrium to height of OR ratio was 1:0.76). An operative corridor to the atrium without damaging the OR can be calculated from MR imaging of the brain.
authors.affiliation: Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States.
authors.forename: Raghuram
authors.initials: R
authors.lastname: Sampath
authors.affiliation: Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States.
authors.forename: Kristopher
authors.initials: K
authors.lastname: Katira
authors.affiliation: Department of Biostatistics, LSUHSC-Shreveport, Shreveport, Louisiana, United States.
authors.forename: Runhua
authors.initials: R
authors.lastname: Shi
authors.affiliation: Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States.
authors.forename: Prasad
authors.initials: P
authors.lastname: Vannemreddy
authors.affiliation: Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States.
authors.forename: Shashikant
authors.initials: S
authors.lastname: Patil
authors.affiliation: Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States.
authors.forename: Anil
authors.initials: A
authors.lastname: Nanda
mesh_terms: D000328:Adult; D000465:Algorithms; D005829:Geniculate Bodies / Q000033:anatomy & histology* / Q000473:pathology; D006801:Humans; D020547:Lateral Ventricles / Q000033:anatomy & histology* / Q000473:pathology; D019635:Neurosurgical Procedures / Q000379:methods* / Q000592:standards; D065866:Optic Tract / Q000033:anatomy & histology* / Q000473:pathology