Multiple subpial transections of cortex
- Done when epileptogenic zone is in the eloquent cortex
- Cortex is instead disrupted by parallel subpial cuts transecting the gray matter every 3-5 mm.
- Intention is to preserve centripetal axonal outflow while isolating silos of epileptogenic neurons by disrupting lateral dendritic communication across gyri, thereby preventing Jacksonian patterns of spreading cortical propagation of seizures.
- The benefit and indications of this technique remain controversial.
Hemispherectomy
General
- Incomplete disconnection may predispose young children to less seizure control.
- Most patients will end up with deficit but child can typically ambulate with an orthotic device and use the hand as a helper hand while receiving special education
- This is eminently better than being developmentally frozen in a stupor or coma from continued daily seizures.
Indication (more for paeds) better neuroplasticity
- Infants and children AND
- Intractable epilepsy from an epilepsy involving an entire hemisphere (poor prognosis)
- West syndrome with malformation of cortical development,
- Rasmussen’s encephalitis,
- Sturge-Weber syndrome
- Chronic encephalitis
- Hemimegalencephaly
Anatomic hemispherectomy
- Often used for children with hemimegalencephaly.
- Involves the removal of a cerebral hemisphere,
- Complications
- Siderosis
- The dura of the cavity following a hemispherectomy may have multiple bleeding points that have direct access to the ventricular system.
Functional hemispherectomy
- Leaves the hemisphere physically intact but functionally disconnected
- Multiple modifications of hemispherectomy have been developed to address various types of complication associated with anatomical hemispherectomy
- Includes
- Hemicorticectomy
- Resection
- Of the cortical Gray matter in all accessible affected regions AND
- The incidence of unexpected neurologic deficits after cortical resection is rare.
- 50% of a presumed eloquent area such as the motor strip can be removed without causing a permanent deficit if the underlying white matter tracts are spared.
- The children often experience a transient deficit that resolves over several weeks.
- Even in children with some developmental delay with a curtailed ability to rehabilitate due to limited cognition, they tend to have a better quality of life without seizures even with a new deficit such as a hemiparesis.
- Temporal lobe.
- Complete corpus callostomy
- See below
- Temporal lobectomy
- Transection of the parietal lobe from the occipital and frontal lobes
- Keyhole hemispherectomy
- Recently developed and may offer adequate seizure control with less surgical morbidity.
Posterior quadrantectomy
- The posterior quadrant consists of the parietal, posterior temporal, and occipital lobes
Partial or complete section of the corpus callosum (Corpus callostomy)
Indication
- Atonic seizures with loss of postural tone leading to falls
- 70% of patients
- Aim is to reduce drop attack resultant injury
- Generalized major motor seizures without an identifiable resectable epileptogenic zone
- Generalized seizures with unilateral hemispheric damage if not deemed candidates for functional or anatomic hemispherectomy (e.g. preserved motor function)
Complications
- Postoperative sequelae of decreased vocalization or akinetic mutism will usually resolve within weeks to months.
- Transient hemiparesis
- Present for about a week
- Due to the retraction on the hemisphere.
- Disconnection syndrome
- Occurs with complete callosotomy
- To avoid
- The anterior 2/3 of the corpus callosum is sectioned, often sparing the anterior commissure;
- In left-handed patients shown by Wada testing to have crossed dominance with speech and handedness in opposite hemispheres,
- Even partial corpus callosotomy is contraindicated to avoid major behavioural and language deficits postoperatively.
- Includes
- Left tactile anomia
- Left dyspraxia
- Pseudohemianopsia
- Right anomia for smell
- Right hand-impaired spatial synthesis and difficulty copying complex figures
- Decreased spontaneity of speech
- Incontinence.
Outcome
- See Graham 2019
- Findings
- 55 patients
- 11 ant 2/3 CC
- 43 complete CC
- 47% good outcome for drops
- Corpus callosotomy rarely results in complete seizure control
- About 80% of children will experience a significant improvement in seizure control and associated quality of life.
Made with Bullet