Interhemispheric Transcallosal Transchoroidal Approach

Interhemispheric Transcallosal Transchoroidal Approach

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 veins 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 veins 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 fibers 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 complications 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 1).


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 ventriclebetween the two internal cerebral veins. 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 2).

see Transtemporal transchoroidal fissure approach


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 3).

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

1)

Cossu, G., González-López, P. & Daniel, R.T. Acta Neurochir (2019). https://doi.org/10.1007/s00701-019-04040-x
2)

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.
3)

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.

Insular Cavernous Malformation

Insular Cavernous Malformation

Surgical management of cavernous malformation (CM) of the insula consists of total resection of the lesion and the surrounding gliosis to avoid or reduce seizures. When located in the dominant hemisphere, an awake craniotomy with intraoperative mapping reduces the risk of functional damage. The insula is covered by the operculum and has a relationship with the middle cerebral artery and its branches that run along its lateral cortical surface. Therefore high expertise is required to manage the exposure of the insula and its complex anatomy.

Videos

https://www.neurosurgicalatlas.com/cases/insular-cavernous-malformation


A video of Burkhardt et al. demonstrated the microsurgical resection of a de novo CM adjacent to a previously treated high-grade AVM and clipping of a middle cerebral artery (MCA) aneurysm. A 70-yr-old male with history of radiosurgery for AVM presented with aphasia and confusion. Preoperative angiography showed complete occlusion of the AVM. MRI showed multiple cystic lesions suspicious for radiation-induced necrosis and CM. IRB approval and patient consent was obtained. A pterional craniotomy was performed with transsylvian exposure of the insula. The radiated feeding arteries were followed to the occluded AVM nidus. A CM was noted deep to this candelabra of the MCA vessels, which were mobilized to access and resect the CM. A small incision was made in this insular cortex underneath the malformation circumferentially freeing it of adhesions. The sclerotic AVM nidus was circumferentially dissected and removed en bloc. Thorough exploration of the resection cavity revealed no residual CM or AVM nidus. Attention was then turned to the M2-MCA bifurcation aneurysm, which was occluded with a straight clip. Postoperative imaging confirmed complete CM resection. The patient recovered from his aphasia. This case demonstrates the management of a radiation-induced de novo CM following treatment of a high-grade AVM. Radiographic follow-up for radiosurgically treated AVM is needed to rule out long-term complications. Bleeding from a de novo CM mimics bleeding from residual AVM nidus, requiring careful angiographic evaluation 1).


A video of Norat et al. illustrated the use of a trans-Sylvian, trans-sulcal approach to resect a deep insular/basal ganglia cavernous malformation in a young patient. The use of the neuronavigation is essential for success in these types of operation as this tool limits the surgeon’s footprint in eloquent brain. Unlike superficial lesions where the removal of hemosiderin stained brain is possible and often safe, resection of deep-seated lesions requires the surgeon to distinguish between hemosiderin-stained brain and residual cavernous malformation. This task is not simple, and residual cavernous malformation is the most common reason for re-bleed in patients who have undergone surgery. Resection of symptomatic cavernous malformations in deep locations can be performed safely, but outcomes are heavily influenced by proper patient selection and surgeon experience. In patients with multiple cerebral cavernous malformations, such as the one in this case, genetic testing should be performed 2).


A video of Vigo et al. demonstrated the surgical management of a large left insular CM. A 29-year-old female with multiple CM and 7 years of partial seizures and recent onset of short memory loss. Neuroimaging showed a large left insular and planum polare CM with important mass effect and hemorrhage signs. The patient consented to surgery, and an awake pretemporal craniotomy was carried out with continuous motor evoked potential monitoring. No language function was localized in the superior temporal gyrus; therefore corticectomy of the middle portion was performed to expand the operative corridor. The vessel manipulation during wide opening of the sylvian fissure increased the risk of postoperative vasospasm and blood drain into the surgical field. The CM was exposed and completely removed without functional damage. The patient recovered from surgery without complications, and no seizures occurred at 2 months’ follow-up. Postoperative imaging showed complete removal of the CM 3).

Case reports

A 25-yr-old female presented with an acute-onset right homonymous hemianopsia. Neuroimaging revealed a large left insular CM, adjacent to the posterior limb of IC. After obtaining IRB approval and patient consent, a left pterional craniotomy with a wide distal Sylvian fissure split was completed. Using neuronavigation, an insular entry point was chosen for corticectomy. The CM was opened with subsequent hematoma evacuation and intracapsular resection technique. Inspection of the cavity revealed remnants anteromedially near the IC, which were removed meticulously, mobilizing the CM away from the IC. Postoperative MRI demonstrated gross total resection of the CM. The patient was discharged home on postoperative day 5 with persistent homonymous hemianopia.This case describes the use of a transsylvian-transinsular approach to access deep lesions with the shortest surgical distance and minimal cortical transgression. A wide Sylvian fissure split exposes the M2 MCA and accesses a safe insular zone, keeping the most eloquent structures deep to the lesion in the surgical corridor. This approach can safely expose vascular pathologies in the insular region without the risk of injury to overlying eloquent frontal and temporal lobes, even in the dominant hemisphere 4).

References

1)

Burkhardt JK, Gandhi S, Tabani H, Benet A, Lawton MT. Left Transsylvian-Transinsular Approach for Radiation-Induced Cavernous Malformation: 3-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2019 Aug 1;17(2):E62-E63. doi: 10.1093/ons/opy357. PubMed PMID: 30418603.
2)

Norat P, Yagmurlu K, Park MS, Kalani MYS. Keyhole, Trans-Sylvian, Trans-Sulcal Resection of an Insular Cerebral Cavernous Malformation: 2-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2019 Jul 1;17(1):E18. doi: 10.1093/ons/opy326. PubMed PMID: 30496497.
3)

Vigo V, Zanabria Ortiz R, Paganelli SL, da Costa MDS, Campos Filho JM, Chaddad-Neto F. Awake Craniotomy for Removal of Left Insular Cavernous Malformation. World Neurosurg. 2019 Feb;122:209. doi: 10.1016/j.wneu.2018.10.220. Epub 2018 Nov 9. PubMed PMID: 30415050.
4)

Mascitelli J, Gandhi S, Wright E, Lawton MT. Transsylvian-Transinsular Approach for an Insular Cavernous Malformation Resection: 3-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2019 Feb 1;16(2):50. doi: 10.1093/ons/opy155. PubMed PMID: 29905877.

Giant middle cerebral artery aneurysm

Giant middle cerebral artery aneurysm

Giant middle cerebral artery aneurysm (size > 2.5 cm)

Case reports

Bendok et al. presented the case of a 61-year-old female who was brought to the emergency room after she had partial complex seizures. CT and MRI of the brain revealed a right temporal lobe mass which was initially thought to be a tumor. The patient was therefore referred to us for further management. The round nature of the lesion raised suspicion for an aneurysm. A CT angiography was performed followed by a diagnostic conventional cerebral angiogram and confirmed the presence of a giant thrombosed aneurysm 1).


A video case illustrates key surgical steps required in safe management of a giant recurrent previously coiled MCA aneurysm. The patient described in this case was a 68-year old male who presented with a sudden onset severe headache and dizziness. The patient had a history of a prior coil embolization of a 12 mm left middle cerebral artery aneurysm at an outside hospital. Imaging demonstrated recurrence of now a giant left middle cerebral artery aneurysm with coil compaction and left temporal lobe edema. MRI further demonstrated thrombus in the aneurysm and aneurysm wall enhancement concerning for impending rupture. Given the aneurysm size, imaging features and mass effect, the aneurysm was treated with microsurgical clipping. This case is valuable to the literature with a clear video case illustration of aneurysm dome excision, aneurysm endarterectomy and picket fence aneurysm neck reconstruction. Aneurysm dome excision is critical for treatment of giant aneurysms causing mass effect and was only used in this case as thrombus and coil mass did not allow for direct clipping across the neck without compromise of the MCA M2 branch. Hence, this video highlights key technical tenets, such as safe thrombus removal and adequate cleaning of the endoluminal surface and preparedness for bypass in challenging cases 2).


A 64-year-old woman who suffered subarachnoid hemorrhage in 2005. She was treated with coiling of the aneurysm at an outside institution. She presented to the clinic with headaches and was found on angiography to have giant recurrence of the aneurysm. To allow adequate exposure for clipping, Arko et al. performed the surgery through a cranio-orbito-zygomatic (COZ) skull base approach, which is demonstrated. The surgery was performed in an operating room/angiography hybrid suite allowing for high quality intraoperative angiography. The technique and room flow are also demonstrated. The video can be found here: http://youtu.be/eePcyOMi85M 3).

Videos

Left pterional craniotomy for thrombectomy and clipping of ruptured left MCA giant aneurysm

Cranio-orbito-zygomatic approach of a giant MCA aneurysm in a hybrid angio/OR suite

References

1)

Bendok BR, Abi-Aad KR, Rahme R, Turcotte EL, Welz ME, Patra DP, Hess R, Kalen B, Krishna C, Batjer HH. Tulip Giant Aneurysm Amputation and “Shingle Clip Cut Clip” Technique for Microsurgical Reconstruction of a Giant Thrombosed Middle Cerebral Artery Aneurysm. World Neurosurg. 2019 Aug 2. pii: S1878-8750(19)32108-4. doi: 10.1016/j.wneu.2019.07.192. [Epub ahead of print] PubMed PMID: 31377441.
2)

Glauser G, Piazza M, Choudhri O. Aneurysm Dome Excision and Picket Fence Clip Reconstruction of a Previously Coiled Recurrent Giant MCA Aneurysm: Technical Nuances. World Neurosurg. 2019 Apr 1. pii: S1878-8750(19)30913-1. doi: 10.1016/j.wneu.2019.03.233. [Epub ahead of print] PubMed PMID: 30947002.
3)

Arko L, Quach E, Sukul V, Desai A, Gassie K, Erkmen K. Cranio-orbito-zygomatic approach for a previously coiled/recurrent giant MCA aneurysm in a hybrid angio/OR suite. Neurosurg Focus. 2015 Jul;39(VideoSuppl1):V8. PubMed PMID: 26132625.
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