Neurochirurgie
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After the occurrence of long-term complications of hemispherectomy, various methods have been used to reduce them. The aim was to reduce the large dead space left inside the skull. We have developed an original hemispheric disconnection technique that can achieve the same results as anatomic hemispherectomy in epilepsy, with excellent short- and long term-reliability. The detailed technique is described.
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Hemispheric disconnection has been largely proposed for patients with severe epilepsy associated with a congenital or acquired hemispheric cerebral pathology. The classical procedure of anatomical hemispherectomy was progressively abandoned by neurosurgeons in order to avoid postoperative complications since then hemispherotomy techniques have been developed. Globally, with hemispheric disconnection, the rate of patients becoming seizure-free has been between 50 and 80%. ⋯ Cerebral reorganization has been proved to exist in motor and language recovery. Ipsilateral corticospinal pathways seem to be involved in the movement of hemiplegic limbs. Everyday language can be supported by both hemispheres, but there is an early hemispheric specialization of the left hemisphere according to metaphonologic abilities.
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Surgery of partial epilepsies in childhood has largely benefited from the recent advances of imaging techniques, which carry a triple goal: (1) to contribute to the localization of the epilepsy onset zone, (2) to detect and delineate an underlying lesion, and (3) to study the spatial relationship between the epileptogenic zone and the neighboring functional cortex, in order to select patients and plan the resection. This noninvasive presurgical imaging workup must be compared to clinical and electrical data to estimate the postoperative prognosis, while invasive techniques such as SEEG, cortical stimulations, and IAT often remain indispensable in difficult cases, i.e., in cryptogenic epilepsies. ⋯ Multimodal imaging greatly enhances the sensitivity of all of these techniques. Finally, functional MRI of motor and language functions provide noninvasive cortical mapping of essential functions, using age-adapted paradigms, in cooperating children from age five to six and from IQs around 60.
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The insula is the only cortical part of the brain that is not visible on the surface of the hemisphere, because it is totally covered by the frontoparietal and temporal opercula. The insula is triangular in shape and is separated from the opercula by the anterior, superior, and inferior peri-insular sulci. It is morphologically divided into two parts by the central insular sulcus. ⋯ The literature contains no reports of cases of resection of insular cortex alone; most insular resections are performed in the context of temporal resection, when there is some evidence of seizures originating in the insula itself. Such procedures are risky and their efficacy, in terms of postoperative surgical outcome, has not yet been clearly assessed. In this context, less invasive procedures, such as SEEG-guided radiofrequency thermolesions of the insular cortex, are under investigation.
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Review Case Reports
[The combined petrosal approach. Anatomical principles, surgical technique and indications].
Management of large petroclival tumors requires the use of extensive surgical approaches that usually jeopardize the intrapetrous neuro-otologic structures. To confirm the interest of the combined petrosal approach in this indication, we describe the relevant anatomy and the surgical steps of this procedure. After making a periauricular skin incision and muscle elevation, an occipitotemporal bone flap is shaped. ⋯ The combined petrosal approach is able to provide a wide multidirectional corridor toward the ventral surface of the pons, the basilary trunk and the ipislateral cranial nerves from the oculomotor to the lower cranial nerves. This study confirms that despite a significant extra time needed for proper achievement, the combined petrosal approach is a valuable conservative approach when the petroclival area, ventral brain stem and basilary trunk are targeted. This approach should be included in the panel of the transpetrous routes available by expert skull base teams.