Corpus callotomy

The corpus callosum is the largest commissure fiber, and its traverse fibers form a wide, thick, dense plate between the hemispheres, consisting of approximately 200 million nerve fibers. It is connected to the corresponding area of the two hemispheres. The frontal lobe and the ligament are connected back to the anterior half of the corpus callosum. The temporal lobes are connected by the hippocampus in the posterior and posterior part of the corpus callosum. The rear portions of the pressure portions are connected. Experiments have confirmed that the corpus callosum is the main pathway for epileptic discharge to spread from one hemisphere to the other. Therefore, cutting off the corpus callosum can prevent the epilepsy discharge from spreading, and the patient's epilepsy can be significantly alleviated. The operation was pioneered by Van Wagenen (1939) and has been increasing since the 1960s and is widely accepted by clinicians. After the corpus callosum was removed, although there was a split brain syndrome, the patient did not have any persistent neurological or psychological disorders, and his personality, temper, language, verbal estimation, and memory function were almost unchanged. The effect of measuring the corpus callosum is often judged by Wilson's criteria: 1 excellent, the frequency and/or severity of seizures is reduced by more than 80%; 2 is good, the frequency and/or severity of seizures is reduced by more than 50%, or The type of seizure changes; 3 is acceptable, the frequency and/or severity of seizures is reduced by 25% to 50%; 4 is ineffective or worse. Regardless of the stage or stage of total carcass incision, about 80% to 90% of patients with a loss of tension (falling episodes), tonic or tonic-clonic seizures can be completely stopped or significantly reduced. In the long-term follow-up after partial incision of the corpus callosum, only about 50% of patients with seizures were controlled. At present, it is recommended to use the anterior corpus callosum incision. Treatment of diseases: frontal lobe epilepsy Indication Intractable epilepsy, with loss of tension, rigidity and rigidity - clonic seizures. Frontal lobe epilepsy, multifocal epilepsy, infantile hemiplegia, Lennox-Gastaut syndrome. Some complex partial epileptic seizures without a localization. Contraindications 1. A patient who is able to remove the source of epilepsy. 2. Serious intellectual disabilities are relative contraindications. Preoperative preparation 1. Multiple EEG examinations (at least 3 times), confirmed epileptiform abnormal discharge, but no resectable epileptogenic lesions. 2. CT or MRI examination. 3. Cerebral angiography, excluding vascular lesions. Understand the location of the vein so that the central vein is not damaged during the operation. 4. Neuropsychological examinations, such as WAIS. Surgical procedure 1. Anterior callosotomy (1) Make a straight incision perpendicular to the sagittal sinus 2.5 cm in front of the right frontal coronal suture, about 10 to 11 cm long, and 1/3 of the incision across the midline. However, patients with a dominant right hemisphere or patients with significant left hemisphere lesions may have an incision in the left forehead. (2) The initial skin is pulled by an automatic retractor. The skull was cut in the ring before the coronal suture, and the skull was drilled with a 5 cm diameter trephine. The posterior margin of the bone hole was just at the coronal suture. Place 2/3 of the diameter of the treble on the right side of the midline and remove the skull basin. When cutting the opening skin or burrowing saw bone, the mannitol solution 1g/kg and dexamethasone 10~20mg should be quickly instilled intravenously. The sagittal sinus hemorrhage was covered with gelatin sponge to stop bleeding. However, the method of craniotomy of the midline side bone flap is also used. (3) The dura mater is cut in a curved shape, and the base is facing the sagittal sinus, and the surface of the right frontal lobe is exposed. If the brain is not soft, excessive ventilation should be performed to maintain PCO2 at 3.3 kPa (25 mmHg), and the right ventricle can also be punctured. Release cerebrospinal fluid. When the exposed cortex has a bridge vein into the sagittal sinus, it should be electrocoagulated. (4) Holding the retractor, pulling the right frontal lobe outward, entering the longitudinal fissure along the cerebral palsy, carefully separating the adhesion between the two buckles, usually easy to separate. However, when the patient has had a history of trauma or infection, separation is quite difficult. At this time, it is necessary to carefully operate under the microscope, taking care not to mistake the buckle back for the carcass. Continue to deep separation to find the periorbital artery and retract the artery to the sides. Look at the carcass with a white luster under the artery. Expose the length of the carcass that is required to be cut. (5) The small blood vessels on the surface of the corpus callosum were treated by bipolar coagulation, and the corpus callosum fibers were cut from the posterior and forward directions with a straight stripper until the blue translucent chamber membrane was seen. The fibers of the knees and mouth can be cut with a thin aspirator. If it is strictly cut along the midline of the corpus callosum, it can enter the transparent compartment and avoid entering the lateral ventricle. Cut the first 2/3 of the carcass or 80% of the full length, and the length is 5-8 cm. (6) The dura mater was tightly sutured, the pelvis was repositioned, the periosteum was sutured, the scalp was sutured in two layers, and the rubber was drained from the scalp for 24 h. 2. Posterior callosotomy A straight line incision is made in the plane of the parietal protuberance. The same as the incision and the trephine when the anterior part of the corpus callosum is seen, see Figure 4.9.5-4. The drainage vein that enters the sagittal sinus on the surface of the parietal lobe cannot be severed, and enters the longitudinal fissure as much as possible before or after it, and the right parietal lobe is retracted outward. Showing the posterior part of the carcass, this step is often easier than when the anterior part of the carcass is cut, because the wider cerebral palsy prevents the adhesion between the two buckles, and the retractor can be placed in the corpus callosum. Regardless of whether the front of the carcass was previously cut, the posterior aspect of the carcass is usually cut forward from the trailing edge of the compression portion, and the hippocampus underneath is cut open. The remaining steps are the same as the anterior incision of the corpus callosum. complication 1. Acute disconnection syndrome (acute disconnection syndrome) manifested as silence, left misuse (often mistaken for hemiplegia), left half of the field of neglect (often mistaken for hemianopia), left limb weakness. Bilateral Babinski signs positive, bilateral abdominal wall reflexes disappeared, with strong grip reflex. The left upper extremity muscles are diminished, and there are no naming phenomena, as well as urinary incontinence and dizziness. It can be self-recovery after several days to several months. Often complicated by all carcass cuts, and the symptoms are sudden and persistent. 2. Aseptic ventriculitis and wound infection. 3. Brain edema and cerebral infarction. 4. The posterior commissure syndrome often occurs after the incision of the posterior part of the corpus callosum. It is a sensory disassociation syndrome. Because the sensory input is bilateral, it is of no significance. 5. split brain syndrome The loss of sensory and motor function in the two hemispheres, the patient's daily living ability (such as dressing, eating, shopping, etc.) is almost completely lost, and most patients gradually improve over time. Very few are permanent.