Contralateral Transcallosal Approach Research Articles

Commentary: Interhemispheric Contralateral Transcallosal Approach to a Giant Thalamic Cavernous Malformation: 2-Dimensional Operative Video.

Commentary: Interhemispheric Contralateral Transcallosal Approach to a Giant Thalamic Cavernous Malformation: 2-Dimensional Operative Video.

Interhemispheric Contralateral Transcallosal Approach to a Giant Thalamic Cavernous Malformation: 2-Dimensional Operative Video.

Thalamic cavernous malformations are challenging lesions to approach given their deep location and proximity to eloquent neurovascular structures. Several approaches to this region exist, and small nuances in the location of the lesion dictate different surgical trajectories. For cavernous malformations presenting to the superomedial surface of the thalamus, the interhemispheric transcallosal approach affords an excellent trajectory as the anterior two-thirds of the superomedial thalamus constitutes the lateral aspect of the floor of the body of the lateral ventricle. In addition, when the cavernous malformation extends laterally, the contralateral adjunct of the interhemispheric transcallosal approach provides optimal visualization of the lateral aspect of the lesion. In this video, we present the case of a 31-year-old woman who presented to our institution with a giant hemorrhagic thalamic cavernous malformation that resulted in rapid neurological decline characterized by ataxia, right hemiparesis, and diplopia. The cavernous malformation was removed using an interhemispheric contralateral transcallosal approach. The patient had near complete resolution of her preoperative deficits with mild residual weakness in her right hand at 3-month follow-up. At 3-year follow-up, magnetic resonance imaging revealed no active cavernous malformation, and the patient had no recurrence of symptoms. This manuscript was conducted in accordance with the ethical standards of our institution's Institutional Review Board. The patient gave informed consent for surgery and video recording.

Microsurgical Anatomy and Approaches to the Cerebral Central Core

Through a cadaveric study, we divided the cerebral central core (CCC) into different areas and have proposed a corresponding neurosurgical approach for each sector. As a secondary objective, we analyzed the cortical and subcortical microsurgical anatomy of the CCC. The CCC includes the insula, extreme capsule, claustrum, external capsule, lenticular nucleus, internal capsule, caudate nucleus, and thalamus. Twelve adult human brain hemispheres and one cadaveric head specimen were dissected and studied at the Laboratory of Neuroanatomic Microsurgical of the University of Buenos Aires. Nine cases of CCC neurosurgical pathologies were included in the present study and analyzed. Digital drawings were created of the approaches proposed for each sector of the CCC showing the most relevant surgical details. Photographs of each dissection and measurements obtained were taken. We divided the CCC into a medial, intermediate, and lateral sector, with specific subdivisions for the lateral and medial sectors. The lateral projection of the foramen of Monro was found deep to the third short gyri of the insula with the following distances: anterior insular limen margin, 23.95 mm; posterior insular limen margin, 22.92 mm; superior limiting sulcus, 14.99 mm, and inferior limiting sulcus, 13.76 mm. We have proposed the following approaches: an ipsilateral transcallosal approach, a contralateral transcallosal approach, a choroidal transfissure approach, a trans-splenial approach, transparietal access entering the intraparietal sulcus, and trans-sylvian approach. The preoperative imaging studies should be analyzed using our method to select the most accurate and safe approach. We have provided a description of the limits and anatomy of the CCC using brain dissection, an analysis of operated cases, and useful measurements for the neurosurgeon.

Quantitative Anatomic Analysis of the Transcallosal-Transchoroidal Approach and the Transcallosal-Subchoroidal Approach to the Floor of the Third Ventricle: An Anatomic Study

To compare transcallosal-transchoroidal and transcallosal-subchoroidal approaches to the ipsilateral and contralateral edges of the floor of the third ventricle using quantitative analyses. Five formalin-fixed cadaveric human heads (10 sides) were examined under the operating microscope. Quantitative measurements (area of surgical freedom and angle of attack) were obtained using 3-T magnetic resonance imaging and a StealthStation image guidance system. The limits of the surgical approaches were shown by touching a probe to 6 designated points on the floor of the third ventricle. The transchoroidal approach provided greater surgical freedom than the subchoroidal approach to access ipsilateral and contralateral middle landmarks at the edges of the floor of the third ventricle in both longitudinal and horizontal planes (P ≤ 0.03). No significant difference between the 2 approaches was found in accessing the anterior and posterior landmarks of the third ventricle in each plane. The surgical freedom to the contralateral anterior, middle, and posterior landmarks was greater than to the ipsilateral landmarks in both the transchoroidal and subchoroidal approaches. The transcallosal-transchoroidal approach, compared with the transcallosal-subchoroidal approach, may provide better exposure and require less retraction for removal of ipsilateral or contralateral lesions located in the midbrain or hypothalamus and situated nearthe floor of the third ventricle. The contralateral transcallosal approach with either the transchoroidal or subchoroidal approach may provide good surgical freedom for removal of lesions located near the floor of the third ventricle, such as lesions in the midbrain.

The Contralateral Transcingulate Approach

The contralateral transcingulate approach is a variation of the contralateral transcallosal approach for lesions located in the cingulate gyrus and deep white matter of the medial frontal lobe. To more thoroughly describe the contralateral transcingulate approach by reporting our operative technique and results. This approach positions the head with the midline horizontally, lesion on the upside, allowing gravity retraction of the dependent frontal lobe. Bifrontal craniotomy and splitting of the interhemispheric fissure create a crossing trajectory from the contralateral fissure to the ipsilateral cingulate gyrus that maximizes lateral exposure. Eleven patients with vascular lesions were treated with the contralateral transcingulate approach (9 patients with cavernous malformations and 2 patients with arteriovenous malformations). Eight lesions were located on the left side, 5 in the cingulate gyrus, and 6 in the deep frontal lobe. The falx was cut in 5 patients to extend the crossing trajectory. All lesions were removed completely, with neurological morbidity in 1 patient caused by venous infarction. Although similar to the contralateral transcallosal approach, the contralateral transcingulate approach accesses lesions outside the ventricle and has a steeper crossing trajectory. This approach requires no disruption of brain tissue with lesions on the cingulate surface and only a small incision in cingulate gyrus with lesions in the deep frontal lobe. The ipsilateral pericallosal and callosomarginal arteries provide dependable landmarks for transcingulate dissection. The contralateral transcingulate approach offers an alternative medial approach to lesions near language and motor areas and avoids lateral transcortical approaches, awake speech mapping, and risk to eloquent cortex in the dominant hemisphere.

The contralateral transcallosal approach: experience with 32 patients.

To demonstrate the usefulness of the contralateral transcallosal approach for resecting lesions located laterally in or adjacent to the lateral ventricle. Modifications to the standard ipsilateral transcallosal technique include positioning the head with the midline oriented horizontally, placing the side with the lesion up, and performing the craniotomy and interhemispheric dissection on the contralateral side. This approach avoids a transcortical incision, allows gravity to hold open the interhemispheric fissure, and increases the lateral exposure of the lesion. This approach was used in 32 patients with a variety of lesions, including 6 cavernous malformations, 7 arteriovenous malformations, and 19 tumors of various types. All but three lesions were located on the left side. All six cavernous malformations, all four benign tumors, and four of the seven arteriovenous malformations were resected completely. Malignant tumors were resected subtotally, and three arteriovenous malformations required stereotactic radiosurgery to treat residual deep nidus. There was no surgical mortality. Two patients experienced neurological deterioration. The contralateral transcallosal approach can be used to treat a variety of lesions safely and successfully.

Intraventricular aneurysm of the medial posterior choroid artery clipped via the contralateral transcallosal approach.

In lesions located in the lateral ventricle of the dominant hemisphere the contralateral transcallosal approach provides maximum protection of the dominant side as well as excellent visualization of the cella media of the contralateral lateral ventricle. We demonstrated this safe approach in a rare case with intraventricular aneurysm of the left medial choroid artery. The literature on aneurysms in the lateral ventricle is discussed.