PubMed Health⌕ Search

Biomedical subjects

M H Nayel

Publications and source records attributed to M H Nayel.

5 recordsLinked to original sources

Mutual benefits from epilepsy surgery in developed and developing countries.

The last three decades have seen tremendous progress in the surgical management of patients with intractable epilepsy involving all facets of diagnosis, localization, operative technique, and research. Unfortunately, such progress has taken place and is in operation only in the developed countries of North America, Europe, and Japan. Epilepsy surgery programs in the developing countries of South America, Asia, and particularly Africa, if they exist at all, are the result of the individual efforts of physicians who were fortunate enough to receive their training abroad. These physicians face difficulties in financing their programs and in obtaining the necessary equipment, and they work without the assistance of trained personnel or technicians. The exchange of experience between physicians in developed and developing countries may be mutually beneficial. In the face of the high cost of health care in developed countries, it is unrealistic to expect patients with intractable epilepsy to continue to undergo elaborate investigative procedures indefinitely. On the other hand, physicians in developing countries need to keep updated on the latest technology and research and have to receive the necessary support from developed countries to slowly build up their programs. The global perspective of physicians dealing with epilepsy patients may be broadened by exposure to the experience from the "other side of the fence" and will ultimately lead to better patient education and more focused patient care.

Delivery of Health Care↗

Second operation after the failure of previous resection for epilepsy.

We present our surgical experience with second operations in 15 patients with recurrent intractable partial seizures after resection for epilepsy. The interval from the first operation until the first recurrence of seizures ranged from 1 day to 7 months (mean, 62 days). The interval between the first and second operations ranged from 3 months to 12 years (mean, 38 months). Detailed video-electroencephalographic interictal and ictal recording was performed in all patients (invasive electrodes were used in 11 patients). Ictal onset was shown to be remote from the zone of previous resection in 3 of 15 cases (all 3 extratemporal and in the ipsilateral hemisphere). Recurrent seizures arose from the area of previous extratemporal resection in 2 of 15 patients, and from the area of previous temporal resection in 10 of 15 patients. Both cases of extratemporal recurrences and 3 of the 10 cases of temporal lobe recurrences in the area of previous resection were associated with residual unresected structural lesion. Of the 10 patients with local temporal recurrence, 6 had proven epileptogenicity in the residual mesial structures, and 4 had residual epileptogenicity in the unresected lateral temporal lobe. The patients have been monitored for 8 to 82 months (mean, 18 months) after the second operation: 7 patients (47%) have remained seizure-free and another 5 (33%) have achieved a reduction in seizure frequency of more than 90%. There was no mortality or significant morbidity in this series. We conclude that the extent and distribution of residual epileptogenicity after failed epilepsy surgery are highly variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Extent of mesiobasal resection determines outcome after temporal lobectomy for intractable complex partial seizures.

The extent of resection was assessed in 94 patients who underwent temporal lobectomy for medically intractable complex partial seizures originating from a unilateral seizure focus in the anteromesial temporal lobe. Postoperative magnetic resonance imaging in the coronal plane was used to quantify the extent of resection of lateral and mesiobasal structures according to a 20-compartment model of the temporal lobe. Successful seizure outcome (greater than or equal to 90% reduction in seizure frequency) was accomplished in 83% of the patients (all followed up for more than 1 year; mean duration of follow-up, 25.2 months) and correlated significantly (P less than 0.05) with the extent of mesiobasal resection, regardless of the extent of resection of lateral structures. Successful seizure outcome was accomplished in 81% of the patients with no structural lesions, and also correlated significantly (P less than 0.05) with the extent of mesiobasal resection regardless of the extent of lateral resection. A successful seizure outcome was accomplished in 90% of the 21 patients with structural lesions documented by neuroimaging studies. Two patients who underwent extensive lobectomy without resection of the structural lesion had no reduction in seizure frequency postoperatively. We conclude that the most important factor in determining the outcome of temporal lobectomy in patients with unilateral anteromesial temporal lobe epileptogenicity is the extent of resection of structures in the mesiobasal temporal lobe. In patients with structural lesions, lesion resection may be an added contributor to successful seizure outcome.

Epilepsy, Temporal Lobe↗

Differences of in vitro electrophysiology of hippocampal neurons from epileptic patients with mesiotemporal sclerosis versus structural lesions.

In vitro electrophysiologic studies of animal hippocampal slice models of epilepsy have generated hypotheses regarding cellular pathophysiologies associated with epileptogenesis. We tested some of these hypotheses using in vitro intracellular recordings of hippocampal neurons from patients with intractable temporal lobe epilepsy. We compared the electrophysiology of hippocampal neurons from 14 patients with mesiotemporal sclerosis with hippocampal neurons from 7 epileptic patients with structural lesions near the hippocampal biopsy. Both spontaneous and stimulus-evoked synaptic function and action potential firing patterns were observed. Presumed pyramidal neurons from sclerotic hippocampus were significantly less likely to display stimulus-evoked inhibitory postsynaptic potentials (IPSPs) and were more likely to fire spontaneously in bursts of action potentials than were hippocampal neurons from patients with structural lesions. No significant differences were detected in spontaneous postsynaptic potentials, spontaneous rhythmic synaptic events, spontaneous or anode break action potentials, stimulus-evoked excitatory postsynaptic potentials, or stimulus-evoked action potential bursts. Cellular membrane parameters were similar in the two groups, including resting membrane potential, action potential amplitude, action potential half-width, action potential threshold, input resistance, time constant, input/output relationship, and afterhyperpolarization amplitude.

Action Potentials↗