How the brain can rewire itself after an injury: the lesson from hemispherectomy

Does a post-lesional rewiring exist in the central nervous system （CNS）？ Whereas neuroimaging and neuromodulation techniques illustrate the extensive cortical reshaping after a brain injury, the remodeling of ascending and descending neuronal pathway is more difficult to be investigated. Here, we discuss how the studies dealing with hemispherectomy （HS） can provide interesting information about the functional and anatomical reorganization which take place after an extensive unilateral lesion. Indeed, studies in humans and animal models of HS clearly illustrate that the brain is capable of a widespread rewiring between the contralesional cortices and the subcortical structures as well as the medullary segments linked to the affected side of the body.

Hemispherectomy for symptomatic hemiconvulsion-hemiplegia-epilepsy:A case report

We described a case of hemiconvulsion-hemiplegia-epilepsy syndrome treated by anatomical hemispherectomy. A 9-year-old boy who suffered from frequent convulsions at 1 month old, left hemiparesis, free of fever, followed by epileptic seizure at 4 years of age, and was diagnosed with hemiconvulsion-hemiplegia-epilepsy syndrome. Clinical manifestations and Wada test results confirmed that the impaired function of the affected cerebral hemisphere had been compensated by the normal hemisphere. The patient was treated by anatomic hemispherectomy. After the operation, the patient was seizure-free, but did not take any anti-epileptic drugs, and the hemiplegia was not aggravated. These findings demonstrated that the cortex controlling sensory and motor function has transferred.

Assessing structural integrity of the pyramidal tracts with difusion spectrum imaging to predict postoperative motor function in pediatric epilepsy patients with hemispherectomy

Background:Hemispherectomy is an efective treatment option for patients with drug-resistant epilepsy caused by hemispheric lesions.However,patients often have deterioration of their motor functions postoperatively.Difusion spectrum imaging(DSI)was reliable in presenting the natural shape of the white matter fbers.At the same time,the natural sprawl pyramid tract(PT)might be more intuitive for predicting postoperative motor functions.Therefore,we assessed the motor functions by the natural shape revealed by DSI tractography.Methods:Ten children with drug-resistant epilepsy who were candidates for hemispherectomy performed DSI PTs tractography and transcranial magnetic stimulation(TMS)for motor mapping.The motor function was evaluated with muscle strength and hand grasping capability.Pyramidal tract(PT)structural integrity and TMS mapping results were compared between patients who remained stable and those with deteriorated motor functions.Receiver operating characteristic(ROC)curves with PTs asymmetric ratio were analyzed to evaluate DSI tractography diagnostic value.Results:All patients underwent DSI acquisition,while four patients successfully performed TMS.One patient had no response to TMS until the maximal machine output was reached.Four patients failed to perform TMS due to lacking cooperation.One patient was contraindicated to TMS.DSI successfully reconstructed the sharp angle fan-shaped PTs within the hemisphere.The accurate fber distribution with fber termination and thickness within the lesioned hemisphere was replicated with DSI tractography.No signifcance was found in patients’age,sex,seizure frequency,or medication between patients with stable or deteriorated postoperative motor functions.DSI efectively predicted postoperative motor function as stable with damaged PTs,mild deterioration with atrophied PTs,and intact PTs with contralateral innervation confrmed by intracranial stimulation.The area under the curve(AUC)of DSI tractography was 0.84.According to ROC,the cut-of value of PTs asymmetric ratio was 11.5%with 100%sensitivity and 75%specifcity.The sensitivity and specifcity of TMS were 2/3 and 1/2,respectively.Conclusions:The anatomic integrity of PTs with DSI tractography could efectively predict postoperative motor function after hemispherectomy.This enables neurosurgeons to inform patients and relatives about postoperative motor functions with direct morphological evidence of PTs to help them with their surgical decisions.

Functional hemispherectomy for patients with adult-onset Rasmussen’s encephalitis

Background:Surgical treatment for patients with adult-onset Rasmussen’s encephalitis(A-RE)is rarely reported.We investigated the clinical and surgical features of two patients with A-RE who underwent functional hemispherectomy.Case presentation:The data of clinical manifestations,neuroimaging,surgical treatment and surgical outcomes of two patients with A-RE was reviewed.The two patients initially presented with recurrent partial seizures or secondly generalized tonic clonic seizures.Gradually,the patients showed unilateral limb paralysis as well as chronic focal epileptic status.Both patients underwent functional hemispherectomy and achieved seizure freedom in the followup.The contralateral neurological deficits improved gradually after rehabilitation and were acceptable for the selfcare of daily living.The living quality improved prominently after surgery.Conclusions:Despite the risk of hemiplegia,functional hemispherectomy may be a choice for patients with A-RE for favorable seizure control and improved quality of life in selected patients.

Predictors of perioperative complications after surgical intervention of Sturge-Weber syndrome

Objective:lobectomy is an effective therapy for patients with Sturge-Weber syndrome(SWS).Perioperative complications often play a critical role for SWS patients’rehabilitation.This study aimed to explore and the factors of perioperative complications in SWS patients.Methods:we reviewed retrospectively the clinical profile of totally 60 SWS patients who received surgically treatments in Sanbo Brain Hospital,Capital Medical University,from March 2009 to April 2018.Univariate analyses were used to identify the potential predictors of perioperative complications.Results:the average hospitalization time of 60 patients was(35.57±10.79)d.After surgery,54(90.00%)patients reached Engle I level.The most common postoperative complications were fever(83.33%),motor function damage(38.33%)and hyponatremia(55.00%).Univariate analyses revealed that mental retardation,seizure types and surgery types could be the predictive factors for postoperative complications.Conclusion:postoperative complications are common in SWS patients.Prediction of the severity can help doctors know what kind of special care SWS patients need to help them for further rehabilitation.

Long-term P300 in hemispherectomized patients

Background In the years around 1990, in Beijing 13antan Hospital Affiliated to Capital Medical University many children with infantile hemiplegia and intractable epilepsy were treated with further modified anatomical hemispherectomy. We report the follow up of the first six cases. To make good use of these precious clinical data and make clear their neuropsychological state, we performed neuropsychological and neurophysiological measurements in these patients, who were at a median of 17.8 years after hemispherectomy. Methods Oddball task was given to the patients and to a normal control group to collect the peak latency （PL） and peak amplitude （PA） of event-related potentials （ERPs）-P300. The P300 data of the two groups were analyzed and the P300 patterns of the six patients are presented. The baseline characteristics and long-term follow-up of the six hemispherectomized patients, especially the long-term seizure control and cognitive function after surgery, are described. Results Five patients had no seizures and one was almost seizure-free during the years after surgery. Clear P300 was obtained from every electrode in the patients. Differences of P300 between patients and normal control group had no statistical significance. And the maximum PA was at the site of electrode Pz or Cz which was consistent with that of the control group and with previous findings. Conclusions Further modified anatomical hemispherectomy has preferable long-term antiepileptic effects. The P300 results of the patients mean that the basic cognitive function of the patients has no difference from the control group. This reflects the plasticity of the hemisphere to some extent and increases the affirmation of the long-term curative effects of further modified anatomical hemispherectomy from both neuropsychological and neurophysiological aspects.