April 29, 2016
This video describes the general principles for exposure in a section of peri-atrial tumors via the posterior interhemispheric Transfalcine Transprecuneus corridor. This approach is quite feasible and effective for resection of deep-seated peri-atrial tumors without significant transgression or retraction of the normal brain. This is a 62-year old male who presented with six months' history of progressive altered mental status and on MRI evaluation was noted to have a relatively heterogeneous mass along the medial and lateral walls of the Trigone or atrial region. There is significant amount of edema associated with the mass. You can see on the coronal image the location of the tumor. Traditional operative approaches to this lesion include subtemporal potentially which I believe is unlikely to reach this tumor versus transtemporal or trans superior pried or lobial corridors. The transtemporal approach is associated with risk of speech difficulty and requires significant amount of retraction on their functional cortesis in the area of the wearing a keys cortex. The trans superior pridal labial transgresses the brain significantly and is also associated with remarkable amount of retraction to reach the lesion. The posterior interim is very contralateral. Transfalcine approach reaches and exposes the tumor through minimal transgression of the precuneus cortex and is most likely the safest approach to excising this tumor. This patient was also noted to have a lung mass, which subsequently was diagnosed as lung cancer. And therefore these tumor's final diagnosis was consistent with adrenal carcinoma. Also, the amount of edema associated with the ipsilateral hemisphere would obviate the use of a ipsilateral interhemispheric approach as the lateral pole of the tumor cannot be easily reached without significant retraction of the swollen and adenitis hemisphere. Let's go ahead and review the basic principles of the Transfalcine Transprecuneus approach via the contralateral interhemispheric corridor. This tumor is located on the left side. The incision is primarily extended toward the right side. It crosses the midline. The patient head makes a 45 degree angle with the floor. This position of the head allows the use of gravity retraction to mobilize their unaffected or normal hemisphere away from the midline. The exposure of the superior sagittal sinus is important for expansion of the intermediary corridor and therefore the bone removal will be beyond the midline and the incision also extends beyond the midline. Neuronavigation is used. A Lumbar drain is also used to decompress the brain early on. The neuronavigation guides me in avoidance of parasagittal veins. You can see the two veins posterior and anterior to the center of the craniotomy. You can also see the Transfalcine approach and the center of attention for the craniotomy contralateral to the tumor. Let's go ahead and review the exposure. You can see the superior sagittal sinus here. This is the right side, or the unaffected side. This is the left side. The craniotomy has crossed the midline. This is anterior. This is posterior. And we're going to expand the operative corridor around the normal hemisphere. The bridge remains are gently untethered. CSF is drained. Two stitches are placed across the superior falx, just inferior to the superior sagittal sinus to mobilize the sinus away from the operative corridor. Here is the principle of the contralateral Transfalcine approach to the area of the pre-atrial. You can see that the T-shaped incision within the falx exposes the medial posterior parietal hemisphere two sutures reflect and mobilize the Falcine flaps and Cottonoid sutures over the brain protect the brain. We are going to make incision within the precuneus to reach the area of the atrium. Here is an operative view of the illustration I just reviewed. Neuronavigation again identifies the minimum amount of cortical transgression necessary to reach the tumor. You can see that, through the small corticotomy, the choroid plexus is identified early. Tumor devascularisation accomplished also early. However, the other approaches, which reached the tumor from the ipsilateral transcortical route exposed the vascular pedicle of the tumor late in dissection and this principle may lead to excessive bleeding during tumor resection. The Transfalcine approach also exposes the important walls of the ventricle early and this early anatomical orientation assists me with protection of important neurovascular structures. A moment ago you witnessed the resection of the tumor. Here again is the Transprecuneus operative corridor toward the atrium. There's minimal amount of cortical transgression. The closure is conducted in standard fashion. The postoperative MRI demonstrates coral stone removal of the tumor without any significant injury to the normal hemisphere. This patient recovered from the surgery uneventfully. Thank you.
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