====== Interhemispheric Transcallosal Transchoroidal Approach ======
{{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/1Hec49aSb4FGBVN8CP21lR23lHZM4Q8cwjA_kxdenZao1J4MGd/?limit=15&utm_campaign=pubmed-2&fc=20240827052022}}
===== Key points =====
1. The [[transchoroidal approach]] is a versatile approach to access lesions situated within the [[third ventricle]] predominantly behind the [[foramen of Monro]].
2. The anatomy of the [[bridging vein]]s should be studied to plan a safe and adequate [[craniotomy]].
3. [[Neuronavigation]] could be helpful in estimating the positions of the venous structures in the [[approach]] and the ideal trajectory to the lesion in order to perform an adequate placed [[callosotomy]].
4. The anatomy of the lesion in relation to the anatomy of the deep venous system, namely the septal, [[thalamostriate vein]] and [[internal cerebral vein]]s should be carefully analyzed on the pre-operative MRI.
5. The pre-operative [[MRI]] along with [[DTI]] should be analyzed to estimate the displacement of important [[projection fiber]]s in relation to the lesion.
6. Great respect needs to be given to all the venous structures and any sacrifice of a [[vein]] should be made with caution.
7. The [[complication]]s related to the thalamostriate vein and its branches occur much less frequently when compared to the subchoroidal approach.
8. The thalamo-geniculate and thalamo-perforating arteries should be carefully preserved during perilesional dissection.
9. Post-resection [[external ventricular drainage]] can be helpful in avoiding early [[postoperative hydrocephalus]].
10. In cases of diencephalic-mesencephalic lesions, steroids could be helpful in reducing [[edema]] in the early postoperative period
((Cossu, G., González-López, P. & Daniel, R.T. Acta Neurochir (2019). https://doi.org/10.1007/s00701-019-04040-x)).
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It is a subtype of [[Interhemispheric approach]].
This [[approach]] consists of opening the [[taenia fornicis]] of the [[choroidal fissure]] in the body of the [[lateral ventricle]] and approaching the [[third ventricle]] between the two [[internal cerebral vein]]s. This route allows further posterior enlargement of the [[foramen of Monro]] without sacrificing any neural structures. When necessary, the [[anterior septal vein]] can be sacrificed.
Twenty adult cadaveric brains and four adult cadaveric heads were studied, using a magnification ranging from 3 times to 40 times, after perfusion of the arteries and veins with colored latex.
The choroidal fissure is a natural cleft between the thalamus and the fornix, and it is identified by following the choroid plexus in the lateral ventricle. The choroid plexus in the body of the lateral ventricle originates from the tela choroidea of the roof of the third ventricle and is apparently attached to the fornix by the taenia fornicis and to the thalamus by the taenia choroidea. The taenia is actually the ependyma that covers the internal wall of the ventricular cavity and the choroid plexus.
An understanding of the choroidal fissure is fundamental for use of the transchoroidal approach. Unlike transforaminal, subchoroidal, subforniceal, and interforniceal approaches to the third ventricle, which sacrifice some neural or vascular structures, the transchoroidal approach follows a natural route, and certainly it is one of the options to be considered when entry into the third ventricle is required
((Wen HT, Rhoton AL Jr, de Oliveira E. Transchoroidal approach to the third
ventricle: an anatomic study of the choroidal fissure and its clinical
application. Neurosurgery. 1998 Jun;42(6):1205-17; discussion 1217-9. PubMed
PMID: 9632178.
)).
see [[Transtemporal transchoroidal fissure approach]]
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Ito et al demonstrate an interhemispheric transchoroidal approach for third ventricular teratoma resection. Interhemispheric dissection exposed the corpus callosum at a length of about 2 cm. A callosotomy was made to enter into the right lateral ventricle. After septal vein ligation, dissection was made of the space between the right fornix and right internal cerebral vein (ICV); thus bilateral fornix and left ICV would be retracted to the left; right choroid plexus, right ICV to the right. By this transchoroidal approach, the foramen of Monro was extended posteriorly, providing enough of a surgical corridor to resect a posteriorly located third ventricular tumor. The video can be found here: https://youtu.be/gIzPiH3zx_o
((Ito Y, Inoue T, Tamura A, Tsutsumi K. Interhemispheric transchoroidal approach
to resect third ventricular teratoma. Neurosurg Focus. 2016 Jan;40 Video Suppl
1:2016.1.FocusVid.15401. doi: 10.3171/2016.1.FocusVid.15401. PubMed PMID:
26722682.
)).
Interhemispheric transcallosal route for resection of anterior third ventricular lesions
Peker HO, Aydin I, Dinc C, Baskaya MK. Microsurgical Resection of Thalamic Astrocytomas Via Anterior Interhemispheric Transcallosal Transchoroidal Approach: Demonstrating of Technique: 3-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2018 May 1;14(5):595. doi: 10.1093/ons/opx196. PubMed PMID: 28961966.
===== References =====