Ahsan N.V. Moosa

Longitudinal seizure outcome and prognostic predictors after hemispherectomy in 170 children

Objective: Data on longitudinal seizure outcome after hemispherectomy in children are limited. This study explores the posthemispherectomy longitudinal seizure outcome and its predictors. Methods: We reviewed 186 consecutive children who underwent hemispherectomy between 1997 and 2009 at our center. Clinical, EEG, imaging, and surgical data were collected. Seizure outcome data were collected via a structured questionnaire by contacting families (n = 125) or from the medical records at last follow-up (n = 58). Results: Of 186 patients, 3 were lost to follow-up; 13 seizure-free patients with new-onset nonepileptic spells were excluded. Perioperative complications were not collected. There was no mortality. At a mean follow-up of 5.3 years (±3.3 years), 112 of 170 children (66%) were seizure-free (Engel class 1a). In 58 patients with seizure recurrence, 8 had late remission and 16 had >90% reduction. Overall, at last follow-up, 136 patients (80%) were either seizure-free or had major improvement. Using survival analysis, the estimated probability of seizure freedom after hemispherectomy was 78% (95% confidence interval [CI] = 75%–81%) at 6 months, 76% (95% CI = 73%–79%) at 1 year, 71% (95% CI = 68%–74%) at 2 years, and 63% (95% CI = 59%–67%) at 5 years. On multivariate analysis, bilateral PET abnormalities (risk ratio = 2.53, 95% CI = 1.02–5.85) and acute postoperative seizures (risk ratio = 7.03, 95% CI = 3.07–15.9) independently predicted seizure recurrence. Conclusions: The long-term seizure-free rates after hemispherectomy remained stable at 63% at 5 years and beyond. This study will assist in better candidate selection for hemispherectomy, presurgical counseling, and early identification of surgical failures.

Long-term functional outcomes and their predictors after hemispherectomy in 115 children.

To examine the long‐term functional outcomes and their predictors using a patient/family centered approach in a cohort of children who had hemispherectomy. Functional outcome measures studied were the following: ambulation ability, visual symptoms, spoken language, reading skills, and behavioral problems.

Reoperative hemispherectomy for intractable epilepsy: A report of 36 patients

BACKGROUND In patients with medically intractable epilepsy and diffuse unilateral hemispheric disease, functional or disconnective hemispherectomy is a widely accepted and successful treatment option. If recurrent seizures develop after disconnective hemispherectomy, management options become more complex and include conversion to anatomic hemispherectomy. OBJECTIVE To present the outcomes of all patients undergoing reoperative hemispherectomy in 1 institution by 1 surgeon since 1998. METHODS The medical records, operative reports, and imaging studies for 36 patients undergoing reoperative hemispherectomy for continuing medically intractable epilepsy from 1998 to 2011 at Cleveland Clinic were reviewed. Patient characteristics, cause of seizure, imaging findings, surgery-related complications, and long-term seizure outcomes were evaluated. RESULTS Patients presented with a variety of seizure origins, including Rasmussen encephalitis, perinatal infarction, cortical dysplasia, and hemimegalencephaly. Overall, 19% of patients were seizure free after conversion to anatomic hemispherectomy, and 45% reported a decrease in seizure frequency by ≥ 90%. An additional 36% reported no improvement. Generalized ictal electroencephalography tended to confer a poorer prognosis, as did cortical dysplasia as the underlying diagnosis. CONCLUSION The possibility that residual epileptogenic tissue in the operated hemisphere remains connected should be considered after failed functional hemispherectomy because our data suggest that improvement in seizure frequency is possible after reoperative hemispherectomy, although the chance of obtaining seizure freedom is relatively low. The decision to proceed with reoperative hemispherectomy should be made after proper discussion with the patient and family and informed consent is given.

Neonatal Stroke and Progressive Leukoencephalopathy in a Child With an ACTA2 Mutation

Mutations in the smooth muscle–specific isoform of α-actin (ACTA2) cause vascular smooth muscle dysfunction leading to aortic aneurysm and moyamoya syndrome. A unique R179H mutation in ACTA2 has been reported to result in widespread smooth muscle dysfunction affecting vascular and extravascular smooth muscles. We report a 7-year-old girl with an ACTA2 R179H mutation manifesting with neonatal seizures due to multifocal infarcts, asymmetric motor deficits, global developmental delay, spasticity, congenital bilateral mydriasis, and a large patent ductus arteriosus. Serial magnetic resonance imaging (MRI) of the brain over 7 years showed diffuse supratentorial white matter abnormalities consistent with a progressive leukoencephalopathy. Magnetic resonance angiography of the cerebral vessels showed stenosis in the terminal portion of the bilateral internal carotid arteries with fusiform dilation of the proximal segment. Neonatal onset of neurologic symptoms in ACTA2 mutations has not been previously reported. R179H mutation in ACTA2 represents the severe end of the disease spectrum.

MRI of metronidazole induced cerebellar ataxia

Central nervous system neurotoxicity to metronidazole is exceedingly rare. This case illustrates characteristic MRI changes associated with metronidazole-induced cerebellar ataxia. A 52-year-old man with remote post-traumatic T7 paraplegia presented with acute-onset dysarthria and upper-limb ataxia. He reported to the local emergency department 2 h after coworkers noticed slurred speech. He had a mild inability to button his shirt and drive his car due to clumsiness of hands for the preceding 2 days. Dysarthria rapidly worsened over next 3 days. His past medical history included T7 paraplegia following a motor vehicle accident at 22 years of age and chronic osteomyelitis of right ischium of 2 years. He has been on several courses of antibiotics and surgical debridement …

Re-review of MRI with post-processing in nonlesional patients in whom epilepsy surgery has failed

Management of MRI-negative patients with intractable focal epilepsy after failed surgery is particularly challenging. In this study, we aim to investigate whether MRI post-processing could identify relevant targets for the re-evaluation of MRI-negative patients who failed the initial resective surgery. We examined a consecutive series of 56 MRI-negative patients who underwent resective surgery and had recurring seizures at 1-year follow-up. T1-weighted volumetric sequence from the pre-surgical MRI was used for voxel-based MRI post-processing which was implemented in a morphometric analysis program (MAP). MAP was positive in 15 of the 56 patients included in this study. In 5 patients, the MAP+ regions were fully resected. In 10 patients, the MAP+ regions were not or partially resected: two out of the 10 patients had a second surgery including the unresected MAP+ region, and both became seizure-free; the remaining 8 patients did not undergo further surgery, but the unresected MAP+ regions were concordant with more than one noninvasive modality in 7. In the 8 patients who had unresected MAP+ regions and intracranial-EEG before the previous surgery, the unresected MAP+ regions were concordant with ictal onset in 6. Our data suggest that scrutiny of the presurgical MRI guided by MRI post-processing may reveal relevant targets for reoperation in nonlesional epilepsies. MAP findings, when concordant with the patient’s other noninvasive data, should be considered when planning invasive evaluation/reoperation for this most challenging group of patients.

Focal epileptogenic lesions

The spectrum of focal epileptogenic lesions and their clinical manifestations in children differ substantially from those seen in adults. In adults, mesial temporal sclerosis is the common lesion in surgical series; but in children, MTS is uncommon, and when it does occur, it exists frequently as dual pathology. The most common lesions in pediatric epilepsy surgery candidates are malformations of cortical development, developmental tumors, or encephalomalacia from infarction, hypoxia, trauma, or infection. Careful analysis of the lesion characteristics on brain MRI is sufficiently predictive of pathology in most cases. Histopathological evaluation remains the gold standard for diagnosis of mass lesions. The electroclinical phenotype of epilepsy in adults is largely determined by the anatomical location of the lesion and its connectivity. In children, in addition to the location of the lesion, the age at onset of the lesion and the age at onset of epilepsy have a major impact on the electroclinical phenotype. Children with congenital or early acquired lesions may manifest with generalized features on EEG and seizure semiology. Experience from various centers has demonstrated that a subset of these children benefit from epilepsy surgery despite a generalized epilepsy phenotype. All children with medically refractory epilepsy and a focal lesion should undergo evaluation for potential epilepsy surgery irrespective of the EEG findings and seizure semiology.

Epilepsy surgery in epidermal nevus syndrome variant with hemimegalencephaly and intractable seizures

A retrospective chart review identified seven patients among 3000 patients (0.23 %) who were admitted to our pediatric epilepsy monitoring unit during a consecutive ten year period and among 21 patients with hemimegalencephaly within this sample (33 %). All patients underwent continuous video-EEG monitoring and neuroimaging for evaluation of seizures. All patients had an epidermal nevus involving the face and MRI evidence of HME.

Outcome after epilepsy surgery for cortical dysplasia in children.

Background and PurposeEpilepsy surgery for medically refractory epilepsy secondary to cortical dysplasia in children poses special challenges. We aim to review the current available literature on the outcome after epilepsy surgery for cortical dysplasia in children and critically evaluate the prognostic predictors of outcome.MethodsA comprehensive review of the literature was performed focusing on the outcome after epilepsy surgery for cortical dysplasia in children. Two large recent meta-analyses that included children and adults and several pediatric series of cortical dysplasia in children were reviewed.Results and ConclusionsThe overall seizure freedom rates range from 40 to 73 %, at about 2 years after surgery; most studies report 50–55% success rate. Complete resection of the epileptogenic lesion/zone remains the most important variable predictive of postoperative seizure freedom. Features unique to cortical dysplasia that limits our ability to ensure complete resection of the epileptogenic zone are reviewed.

Reversible brainstem edema due to hypertensive encephalopathy in an 8-year-old girl.

The authors report an 8-year-old girl with refractory status epilepticus due to hypertensive encephalopathy, secondary to end-stage renal disease. Brain magnetic resonance imaging (MRI) in the acute phase showed striking hyperintensities in the brain stem and medial thalamus along with subtle cortical lesions. After successful control of hypertensive crisis and status epilepticus, the patient recovered to her baseline. Near total resolution of the lesions was noted on follow-up imaging performed 9 days later. Predominant brainstem involvement as a feature of posterior reversible encephalopathy syndrome due to hypertensive crisis is extremely rare in children and has not been well documented.