Pterional transsylvian-transinsular approach in three cavernomas of the left anterior mesiotemporal region

Association between the surgical approach and prognosis of spontaneous supratentorial deep intracerebral hemorrhage

The association between surgical approach and prognosis in patients with spontaneous supratentorial deep intracerebral hemorrhage is unclear. We aimed to explore the association between surgical approach and prognosis in these patients. A retrospective cohort of 311 patients from 3 centers who were treated with surgery 24 h after ictus was recruited. The surgical procedure involved removing the intracerebral hematoma using an aspirator through either the cortical approach or Sylvian fissure approach, assisted by an endoscope or microscope. The primary outcome was the one-year modified Rankin scale (mRS) score. The association between the surgical approach and the one-year mRS score was explored by using ordinal logistic regression and binary logistic regression. Baseline characteristics were balanced by propensity score matching and inverse propensity score weighting. In the adjusted analysis, compared with the cortex approach group, the Sylvian fissure approach group had better one-year mRS scores when analyzed as an ordinal variable (3.00 [2.00-4.00] vs. 4.00 [3.00-5.00]; adjusted odds ratio, 3.15; 95% CI, 1.78-5.58; p < 0.001) and a dichotomous variable (74.14% vs. 49.01%; adjusted odds ratio, 6.61; 95% CI, 2.75-15.88; p < 0.001). Surgical approach was not significantly associated with rebleeding (p = 0.88) or three-month mortality (p = 0.81). In univariate analysis after propensity score matching, there were significant differences in one-year mRS score between the two groups (p < 0.001), and there were no significant differences in rebleeding (Fisher's exact test, p > 0.999) or three-month mortality (Fisher's exact test, p > 0.999). Inverse probability weighted regression analysis showed better one-year mRS scores when analyzed as an ordinal variable (adjusted odds ratio, 3.03; 95% CI, 2.17-4.17; p < 0.001) and a dichotomous variable (adjusted odds ratio, 3.11; 95% CI, 2.16-4.77; p < 0.001) in the Sylvian fissure approach group; the surgical approach was not significantly associated with rebleeding (p = 0.50) or three-month mortality (p = 0.60). In the surgical treatment of patients with spontaneous supratentorial deep intracerebral hemorrhage, the Sylvian fissure approach may lead to a better functional outcome compared with the cortex approach. Future prospective studies are warranted to confirm this finding.

Blood supply to the corticospinal tract: A pictorial review with application to cranial surgery and stroke

The corticospinal tract (CST) is the main neural pathway responsible for conducting voluntary motor function in the central nervous system. The CST condenses into fiber bundles as it descends from the frontoparietal cortex, traveling down to terminate at the anterior horn of the spinal cord. The CST is at risk of injury from vascular insult from strokes and during neurosurgical procedures. The aim of this article is to identify and describe the vasculature associated with the CST from the cortex to the medulla. Dissection of cadaveric specimens was carried out in a manner, which exposed and preserved the fiber tracts of the CST, as well as the arterial systems that supply them. At the level of the motor cortex, the CST is supplied by terminal branches of the anterior cerebral artery and middle cerebral artery. The white matter tracts of the corona radiata and internal capsule are supplied by small perforators including the lenticulostriate arteries and branches of the anterior choroidal artery. In the brainstem, the CST is supplied by anterior perforating branches from the basilar and vertebral arteries. The caudal portions of the CST in the medulla are supplied by the anterior spinal artery, which branches from the vertebral arteries. The non-anastomotic nature of the vessel systems of the CST highlights the importance of their preservation during neurosurgical procedures. Anatomical knowledge of the CST is paramount to clinical diagnosis and treatment of heterogeneity of neurodegenerative, neuroinflammatory, cerebrovascular, and skull base tumors.

Brain folding shapes the branching pattern of the middle cerebral artery

The folds of the brain offer a particular challenge for the subarachnoid vascular grid. The primitive blood vessels that occupy this space, when the brain is flat, have to adapt to an everchanging geometry while constructing an efficient network. Surprisingly, the result is a non-redundant arterial system easily challenged by acute occlusions. Here, we generalize the optimal network building principles of a flat surface growing into a folded configuration and generate an ideal middle cerebral artery (MCA) configuration that can be directly compared with the normal brain anatomy. We then describe how the Sylvian fissure (the fold in which the MCA is buried) is formed during development and use our findings to account for the differences between the ideal and the actual shaping pattern of the MCA. Our results reveal that folding dynamics condition the development of arterial anastomosis yielding a network without loops and poor response to acute occlusions.

III cranial nerve cavernous malformation: A case report and review of the literature

Background:

Cavernous malformations generally occur in brain parenchyma but rarely these lesions arise from cranial nerves (CNs).

Case Description:

This paper described a case of a woman presented with III CN dysfunction due to the presence of a right III CN cavernoma. Surgical treatment with nerve sparing gross total resection was performed. A 3-month follow-up was documented.

Conclusion:

Only few cases of CNs cavernomas have been described in the literature. These lesions have been described to show a more aggressive behavior compared to intraparenchymal cavernomas, especially in symptomatic patients. Differential diagnosis and surgical treatment could be challenging, especially trying to preserve nerve integrity and function.

Spatial convergence of distant cortical regions during folding explains why arteries do not cross the sylvian fissure

OBJECTIVE

Cortical folding places regions that are separated by a large distance along the cortical surface in close proximity. This process is not homogeneous; regions such as the insular opercula have a much higher cortical surface distance (CSD) to euclidean distance (ED) than others. Here the authors explore the hypothesis that in the folded brain the CSD, and not the ED, determines regions of common irrigation, because this measure corresponds more closely with the distance along the prefolded brain, where the subarachnoid arterial vascular network starts forming.

METHODS

The authors defined a convergence index that compared the ED to the CSD and applied it to the cortical surface reconstruction of an average brain. They then compared cortical convergence to the irrigation patterns of major sulci and fissures of the brain, by assessing whether these structures were crossed or not crossed by arterial vessels in 20 fixed hemispheres.

RESULTS

The regions of highest convergence (top 1%) were clustered around the sylvian fissure, which is the only brain depression with high convergence values along its edges. Arterial crossings were commonly observed in every major sulcus of the brain, with the exception of the sylvian fissure, constituting a highly significant difference (p < 10-4).

CONCLUSIONS

Arteries do not cross regions of high convergence. In the adult brain the CSD, rather than the ED, predicts the regional irrigation pattern. The distant origin of the frontal and temporal lobes creates a region of high cortical convergence, which explains why arteries do not cross the sylvian fissure.

Cavernomas and Arteriovenous Malformations in the Mesial Temporal Region: Microsurgical Anatomy and Approaches

BACKGROUND

The mesial temporal region (MTR) is located deep in the temporal lobe and it is surrounded by important vascular and nervous structures that should be preserved during surgery.

OBJECTIVE

To describe microsurgical anatomy and approaches to the MTR in relation to cavernomas and arteriovenous malformations (AVMs).

METHODS

Five formalin-fixed and red silicone-embedded heads of adult cadavers were used for this study. Between January 2003 and June 2014, 7 patients with cavernomas and 6 patients with AVMs in the MTR underwent surgery.

RESULTS

The MTR of the cadavers was divided into 3 areas: anterior, middle, and posterior. Of the 7 patients with MTR cavernomas, 4 were located anteriorly, 2 were located medially, and 1 was located posteriorly. Of the 6 patients with MTR AVMs, 3 were located in the anterior sector, 2 in the middle sector, and 1 in the posterior sector. For the anterior portion of the MTR, a transsylvian-transinsular approach was used; for the middle portion of the MTR, a transtemporal approach was used (anterior temporal lobectomy); and for the posterior portion of the MTR, a supracerebellar-transtentorial approach was used.

CONCLUSION

Dividing the MTR into 3 regions allows us to adapt the approach to lesion location. Thus, the anterior sector can be approached via the sylvian fissure, the middle sector can be approached transtemporally, and the posterior sector can be approached via the supracerebellar approach.

[Microsurgical approach to the ambient cistern]

Objetivo:

Describir paso a paso el abordaje a la cisterna ambiens por la vía suboccipital retrosigmoidea supracerebelosa infratentorial (SRSI).

Descripción:

El abordaje SRSI se realiza de la misma manera que el abordaje suboccipital retrosigmoideo (SR), utilizado habitualmente para acceder a la patología del ángulo pontocerebeloso, con las siguientes modificaciones: (1) utilizamos siempre la posición semisentado, (2) la craneotomia-craniectomia debe exponer el seno transverso y extenderse 5 cm medialmente hacia el inion, (3) al realizar la apertura dural es necesario rebatir la duramadre junto con el seno transverso hacia cefálico con puntos de tracción, (4) bajo magnificación con microscopio quirúrgico se debe realizar la apertura de la cisterna cerebelobulbar para drenar líquido cefalorraquídeo, (5) en el plano supracerebeloso es fundamental cortar las bridas aracnoidales y de ser necesario debemos coagular y cortar las venas puente, todas estas maniobras sumadas al efecto de la gravedad brindan mayor apertura del corredor supracerebeloso.

Conclusión:

El abordaje a la cisterna ambiens por la vía SRSI es una opción segura para el acceso de patologías tumorales que se alojan en esta zona con un componente predominantemente infratentorial.