Frontal controlateral unilateral interhemispheric approach
see also Interhemispheric approach.
The frontal contralateral unilateral interhemispheric approach is a surgical technique used to access and treat lesions or tumors in the brain's frontal lobe through an incision on the opposite side of the brain's midline. This approach allows neurosurgeons to reach lesions in the frontal region that may not be easily accessible through other surgical routes. Here's an outline of the key steps involved:
Patient Positioning: The patient is typically positioned supine on the operating table with the head fixed in a neutral position or slightly turned to one side. The exact positioning may vary depending on the specifics of the lesion and the surgeon's preference.
Incision: A scalp incision is made on the side opposite to the lesion's location, along the midline of the head, and extended towards the frontal region. This incision is carried out through the scalp and down to the skull bone.
Bone Flap Creation: Using a surgical drill or saw, a bone flap is created on the side of the skull opposite to the lesion, extending towards the frontal region. This bone flap is carefully removed to expose the dura mater, the tough membrane covering the brain.
Dural Opening: The dura mater is then opened to expose the brain's surface, extending towards the frontal region. This opening provides access to the contralateral side of the brain where the lesion is located.
Brain Exposure: With the dura opened, the brain is gently retracted or displaced to provide visualization and access to the lesion site within the frontal lobe. Care is taken to avoid damaging healthy brain tissue during this process.
Lesion Resection or Treatment: Once the lesion is adequately exposed, the neurosurgeon can proceed with resecting or treating the lesion using various techniques, such as tumor removal, biopsy, or other interventions tailored to the specific pathology within the frontal lobe.
Closure: After the lesion has been addressed, the dura mater is closed using sutures or other closure materials. The bone flap is then replaced and secured using plates, screws, or other fixation devices. The scalp incision is closed with sutures or staples.
The frontal contralateral unilateral interhemispheric approach offers a unique angle of access to lesions located within the frontal lobe, providing good exposure while minimizing damage to critical brain structures. However, as with any brain surgery, there are associated risks, including bleeding, infection, and neurological deficits. The decision to use this approach depends on factors including the lesion's location, size, and relationship to critical brain structures, as well as the surgeon's expertise and patient-specific considerations.
Q11823
50 year old female
History of superficial spreading melanoma surgically treated 6 years before, with a BRESLOW score of 0.9mm, located on the back. Margins were clear, and sentinel nodes were negative—annual follow-up by Dermatology.
Symptoms began with incomplete responses and some behavioral incoherence over the past weekend, worsening throughout the week with the following symptoms:
Bradypsychia. Incoherent speech. Instability in gait with claudication of the right lower limb. Headache with associated vomiting.
Conscious and oriented in person-time, but disoriented in space. Motor aphasia with bradypsychia and inability for repetition.
Strength preserved in upper limbs, but 4/5 strength in both lower limbs. Recent gait instability with an increased base of support.
Radiological Findings:
Hyperdense solid tumor in the left frontal lobe, probably related to the characteristics of the primary melanoma, with intense enhancement and areas of cystic-necrotic appearance. Contralateral extension through the corpus callosum. Perilesional edema in the left frontal lobe and to a lesser extent in the more medial inferior aspect of the right frontal lobe. Mass Effect with partial collapse of the left frontal horn and right lateral ventricle. Presence of two additional nodular lesions in the left frontal pole.
Diagnostic Impression: Multiple brain metastases in the left frontal lobe, with the largest lesion measuring approximately 5 x 4 x 4 cm with contralateral extension and mass effect. Possible primary tumors include the previously treated melanoma in 2018 or a pulmonary origin due to the presence of a lung nodule not detected in previous radiological studies.
Treatment with high-dose dexamethasone (4mg every 6-8 hours) was initiated.
Right lateral decubitus position
Right Frontal Craniotomy