Surgical treatment of temporal lobe epilepsy
Temporal lobe seizures are the result of brain dysfunction, often with impaired consciousness, and are mostly seen as complex partial seizures. The main clinical manifestations are language disorders: partial aphasia or repetitive language, memory disorders: a sense of having met or not met, or a sense of not having experienced something familiar, or a rapid recall of something experienced in the past;, recognition disorders: including dream-like states, distortion of time perception, a sense of unreality, dissociative states, affective disorders: manifested in seizures as very pleasant or unpleasant feelings, with low self-esteem or Delusions of grandeur: manifested by changes in the size, distance, and appearance of objects, hallucinations: changes in vision, hearing, taste, spatial sense, and object imaging without any external changes.
The seizures in temporal lobe epilepsy are characterized by the presence of disorders of consciousness, which are manifested on the basis of sensory and motor symptoms with more complex symptoms, such as impaired consciousness and psychiatric symptoms, which can occur individually or in succession, or can spread to form grand mal seizures and terminate. Temporal lobe epilepsy is a more common type of epilepsy, and some cases become refractory to regular medical treatment with poor results. Some of these strictly selected cases can be treated surgically with good results.
The main options for surgical treatment of temporal lobe epilepsy are classical anterior temporal lobectomy, medial anterior temporal lobectomy, excision of the temporal lobe neocortex, excision of the structures at the base of the medial temporal lobe (hippocampus, amygdala and parahippocampal gyrus, hook gyrus), selective amygdala and hippocampal resection, and selective amygdala-hippocampal resection with locked foramen (neuronavigation).
Surgical treatment of frontal lobe epilepsy
The incidence of frontal lobe epilepsy is about 20%-30% of partial epilepsy, and frontal lobe epilepsy is more common than temporal lobe epilepsy in childhood. Frontal lobe epilepsy is characterized by simple partial, complex partial, secondary generalized seizures, or a combination of these seizures, depending on whether there is a focal site. Seizures usually occur several times a day and often during sleep. Persistent status epilepticus is a common comorbidity.
Principles of treatment.
1. Secondary frontal lobe epilepsy
(1) Selective focal epileptic foci resection
(2) Combined epileptic foci resection and cortical thermal cautery of functional epileptic foci
(3) Cortical cautery of the functional area alone
(4) Vagus nerve stimulation
2. Idiopathic frontal lobe epilepsy
(1)corpus callosotomy
(2)Vagus nerve stimulation or electrical stimulation of the cerebral cortex
Surgical treatment of insular lobe epilepsy
The concept of “insular lobe epilepsy” was first introduced in the 1950s, when it was discovered that stimulation of the insula could produce symptoms similar to those of temporal lobe epilepsy, and the similarity of clinical symptoms between the two was very confusing. The cross-regional, multicenter clinical case statistics conducted for many years afterwards also showed that among surgically treated temporal lobe epilepsy patients, about 70% had a good prognosis, but 20% had poor surgical outcome, and 10% had ineffective surgical treatment; and among these ineffective patients, insula involvement may be a key reason for treatment failure in some patients with refractory epilepsy after temporal lobectomy alone. The insula belongs to the limbic system and, as a fifth lobe, it is closely associated with visceral activity and emotional centers and is adjacent to motor, sensory, and language centers. The insula has many different functions, such as memory, drive, emotion and higher autonomic control of taste and smell; tumors in the insula region can induce multi-system dysfunction, and improper diagnosis and treatment can be life-threatening.
However, because the insula is part of the limbic system, closely related to visceral activity and emotional centers, and adjacent to motor, sensory, and language centers, surgical resection is likely to damage certain brain functions and tissues of patients and increase the incidence of complications.
Low-power bipolar electrocoagulation and thermal cautery is a safer surgical method that targets intractable epilepsy in functional brain areas and applies bipolar electrocoagulation to the epileptogenic lesion cortex under low output power for 1 to 2 seconds, blocking the horizontal diffusion of epileptic discharges by damaging the superficial layers of the cerebral cortex, reducing cortical excitability and decreasing epileptogenic seizures.
Surgical treatment of parietal lobe epilepsy
Parietal lobe epilepsy is dominated by sensory seizures secondary to generalized seizures, and often manifests complex partial seizures if the epileptic discharges extend beyond the parietal lobe. They are usually characterized by simple partial seizures and secondary seizures. The seizures have many sensory symptoms, such as paresthesia and tingling, and the most frequently affected areas are in the cortical representative areas, where tongue wriggling, tongue stiffening or chilling may occur, and facial sensory phenomena may appear on both sides. Occasionally, a sensation of abdominal sinking, obstruction, or nausea may occur, and in rare cases, pain may be present. The dominant parietal seizures may cause various perceptual or conductive language disorders, and non-dominant parietal seizures may be seen with variable visual hallucinations such as distortion, shortening and lengthening. Sensory symptoms, such as numbness and a sense of absence of a part of the body, may also be seen.
Surgical modality.
The main surgical modality used is resection of the epileptogenic focus or, if adjacent to a major functional area, functional area epilepsy, such as lesion excision, multiple submural transverse fiberotomy, or cortical thermal cautery.
Surgical treatment of occipital lobe epilepsy
Occipital lobe epilepsy presents as a group of syndromes, including vomiting and other vegetative disorders, behavioral abnormalities, eye deviation, and impaired consciousness, which can be followed by generalized convulsive seizures. Early seizures may be characterized only by pale, sweating and other vegetative symptoms, with or without behavioral disturbances. Ophthalmoplegia and vomiting are present in most seizures but can be absent. In a few cases, the seizures are atypical, such as eyes open, no eye deviation, self-induced discomfort, nausea or coughing without vomiting, quietness without agitation, and redness without pallor. Urinary and fecal incontinence and dilated pupils may occur. Visual hallucinations, mouth and throat movements, and automatisms do not usually occur.
The selection of patients for epilepsy surgery is based on whether the patient needs surgery and whether surgery is possible. The need for surgery includes three aspects: the ineffectiveness of regular drug treatment (including the duration of the disease and regular medication), the degree of danger to the patient from seizures, and the significance of treatment; whether surgery is possible depends mainly on the diagnosis of epilepsy and the accurate localization of the epileptic focus.
The surgical procedures for occipital lobe epilepsy can be broadly divided into two categories: those that deal with the site of origin of the epilepsy and those that deal with the transmission pathway of the epilepsy, i.e., blocking its conduction pathway. If the epilepsy is identified as occipital lobe epilepsy, submural fiber transection and thermal cautery of the epileptogenic cortex should be performed under intraoperative EEG monitoring. If the cortical EEG before cautery shows an abnormal EEG background with significant spikes, the cortical layer should be removed directly, especially in the non-dominant hemisphere. In recent years, it has been suggested that localized isolated cerebral dissection is more effective in controlling epilepsy, preserving brain function, and reducing postoperative complications in patients with extensive lesions or EEG abnormalities located in the telencephalon. In some patients, if the transmission of epileptic discharges to the temporal lobe or contralateral occipital lobe is clear, selective hippocampal amygdala resection or posterior corpus callosum dissection via a lateral posterior approach is feasible to reduce or eliminate the possibility of contralateral transmission of epilepsy.