- Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Correspondence Address:
Pravin Salunke
Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
DOI:10.4103/2152-7806.126044
Copyright: © 2014 Salunke P. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.How to cite this article: Salunke P, Sahoo S, Futane S. Successful excision of a pontomesencephalic cavernoma through anterior subtemporal route without mapping: Anatomical landmarks as a road map. Surg Neurol Int 29-Jan-2014;5:15
How to cite this URL: Salunke P, Sahoo S, Futane S. Successful excision of a pontomesencephalic cavernoma through anterior subtemporal route without mapping: Anatomical landmarks as a road map. Surg Neurol Int 29-Jan-2014;5:15. Available from: http://sni.wpengine.com/surgicalint_articles/successful-excision-of-a-pontomesencephalic-cavernoma-through-anterior-subtemporal-route-without-mapping-anatomical-landmarks-as-a-road-map/
Sir,
Brain stem cavernomas account for 9-35% of the total intracerebral cavernomatous malformations.[
A 14-year-old male, presented with bilateral ptosis and right hemiparesis. Magnetic resonance imaging (MRI) showed heteregenous nonenhancing lesion with bleed occupying almost the entire left half of the pontomesencephalic area, extending from the upper midbrain to the mid pontine region in the vertical plane [Figure
Figure 1
Axial MRI showing lesion heterogeneously hypointense on T2 (a) and hyperintense on T1 (b), occupying almost the entire left half of midbrain, suggestive of bleed. (c and d) show coronal MRI revealing the vertical extent of the vascular lesion (cavernoma) from the upper midbrain to the upper pons. (e and f) CEMRI after 8 weeks of surgery showing complete removal of the lesion
Figure 2
Intraoperative images (a) shows entry into the cavernoma through a vertical incision on either side of MPChA, posterior to the third nerve and bulge of pyramidal tract. Also the dorsal potion of lesion can be seen (b) shows removal of cavernoma (c) shows visualization of ventral portion of lesion by turning the table. (d) Schematic diagram to show the relationship of 4th nerve, P2-3 and MPChA in the same axial plane and the parallax effect in subtemporal approach
Brainstem cavernomas are uncommon in pediatric population. These differ from their adult counterpart by the large size and greater chance of rebleed.[
Total removal of the tumor without damaging the nuclei and long tract fibers have better prognosis. Common surgical approaches for brain stem cavernomas are lateral supracerebellar infratentorial, retrosigmoid, presigmoid, subtemporal-occipital, and transpetrosal.[
The entry is at the site of obvious thinning and yellowish discoloration where the hematoma is likely to surface. The Trochlear nerve, P2-3 and MPChA lie in the same axial plane from lateral to medial respectively. However, in the subtemporal approach, MPChA, which is the closest to the brain stem appears to be caudal as compared with P2-3 and trochlear nerve. Thus MPChA forms the horizontal landmark [
Subtemporal transtentorial approach gives an excellent panoramic view of such large ponto-mesencephalic cavernomas. The understanding of anatomical landmarks in varied planes is essential to prevent injury to vital structures especially in nonavailability of navigation facilities. The MPChA, third nerve and bulge of pyramidal tracts forms a good landmark in such cases.
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