J Neurol Surg A Cent Eur Neurosurg 2014; 75(06): 453-461
DOI: 10.1055/s-0034-1368689
Original Article
Georg Thieme Verlag KG Stuttgart · New York

Radio-Anatomic Measurements and Statistical Generation of a Safe Surgical Corridor to Enter the Ventricular Trigone while Avoiding Injury to the Optic Radiations

Raghuram Sampath
1   Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States
,
Kristopher Katira
1   Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States
,
Runhua Shi
2   Department of Biostatistics, LSUHSC-Shreveport, Shreveport, Louisiana, United States
,
Prasad Vannemreddy
1   Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States
,
Shashikant Patil
1   Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States
,
Anil Nanda
1   Department of Neurosurgery, LSUHSC-Shreveport, Shreveport, Louisiana, United States
› Author Affiliations
Further Information

Publication History

29 March 2013

06 November 2013

Publication Date:
25 February 2014 (online)

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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.

Conclusion 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.