Vagal nerve stimulation for drug-resistant epilepsies in different age, aetiology and duration

PURPOSE

The aim of the study was to compare the outcome with respect to age of implant, aetiology and duration of epilepsy.

METHODS

One hundred thirty-five drug-resistant epileptic patients, excluded from ablative surgery, were submitted to vagal nerve stimulation (1995-2007). Aetiology was cryptogenic in 57 and symptomatic in 78 patients. Ages of implant were 0.5-6 years (18 patients), 7-12 years (32 patients), 13-18 years (31 patients) and more than 18 years (54 patients). Epilepsy types were Lennox-Gastaut (18 patients), severe multifocal epilepsy (33 patients) and partial (84 patients). Duration of epilepsy is 3 months to 57 years. Clinical outcome was determined by comparing the seizure frequency after stimulation at 3-6-12-18-24-36 months with the previous 3 months. 'Responders' were the patients experiencing a seizure frequency reduction of 50% or more during follow-up. In statistical analysis, Wilcoxon and McNemar tests, general linear model for repeated measures, logistic regression and survival analysis were used.

RESULTS

The seizure frequency reduction was significant in the group as a whole between baseline and the first follow-up (Wilcoxon test). The percentage of responder increases with time (McNemar test p = 0.04). Univariate analysis showed a significant effect of the age of implant on seizure frequency reduction: Adult patient had worst clinical outcome than children (p < 0.001) and adolescents (p = 0.08). Patients with severe multifocal epilepsy had better percentage seizure reduction compared with Lennox-Gastaut and partial (p = 0.03). Lesser duration of epilepsy had positive influence on outcome. Multivariate analysis confirmed age of implant to be the strongest factor influencing prognosis. Furthermore, positive is the association between lesional aetiology and young age.

CONCLUSIONS

The best responder could be a young lesional epileptic patient; after 3 years of follow-up, the percentage of responders is still in progress.

Radiotherapy and concomitant temozolomide during the first and last weeks in high grade gliomas: long-term analysis of a phase II study

We tested the efficacy and safety of temozolomide (TMZ) when given concomitantly to radiotherapy only in the first and last weeks of treatment to patients affected by high grade gliomas. Conformal radiotherapy (CTV1: tumor bed + residual tumor if present + 1.5 cm, 5,940 cGy, 180 cGy/day; CTV2: oedema, 3,960 cGy, 180 cGy/day) was associated with TMZ, 75 mg/m(2) x 5 days, the first and last weeks of radiotherapy. Adjuvant chemotherapy with TMZ (150 mg/mq daily x 5 days, q28 on the first cycle, 200 mg/mq daily x 5 days, q28 for the following cycles) was given, after chemoradiation, until disease progression or up to 6 cycles. From October 2000 to December 2003, 29 patients (25 GBL, 86.2%; 4 AA, 13.8%) were enrolled in this study. Twenty-two patients (75.8%) received a median 6 cycles of adjuvant chemotherapy with TMZ (range 1-20). Hematological toxicity was absent during concomitant chemoradiation and mild in adjuvant therapy, while neurological toxicity (seizures) was observed only in one case. At a median follow-up of 66 months (range 3-96), median progression-free survival (PFS) was 8 months, with a 1- and 2-year PFS of 46.7 and 28.7%, respectively; median overall survival (OS) time was 21 months, with a 1- and 2-year OS of 69.2 and 42.3%, respectively. In our experience, TMZ proved to be effective even when given only during the first and the last week of radiotherapy, with lower hematological toxicity.

New depth short-latency somatosensory evoked potential (SEP) component recorded in human SI area

To analyse short and long-latency (SEPs) recorded by chronically stereotactically electrodes implanted in SI area of two epileptic patients. Two drug-resistant epileptic patients (2 females, 38 and 15 years, respectively) suffering from left temporal and right frontal epilepsy respectively, were investigated by an electrode-chronically implanted in SI area. Short and long latency somatosensory evoked potentials were recorded by depth electrodes 10 days after implantation. This is the first study to describe a depth N36 response by an intracerebral recording electrode in the SI area, probably generated by a radially oriented generator, located in area 1. Furthermore, we confirmed a role of SI in the genesis of N60 component. Finally, our present data suggest that the SI area is still active at 120 ms after the stimulus, since in one patient (no. 2) we identified a N120 potential, reaching its maximal amplitude at the same depth as the N20 response.

Can a conventional schedule of radiation therapy be administered to elderly patients with glioblastoma multiforme?

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Background: We retrospectively evaluate the tolerance and the efficacy of a conventional schedule of radiotherapy in elderly patients with glioblastoma multiforme (GBM). Methods: Eighty-three consecutive patients affected by glioblastomas were treated between 2001 and 2006. We divided our series in two groups: patients under 65 years (n=52) and patients ≥ 65 years old (n=31). In the elderly group, median age was 68 years (range, 65–80). 17 patients (54,8%) were female, 14 male (45,2%); 20 patients (64,5%) <70 years, 11 patients (35,5%) ≥70 years. Among the younger patients, median age was 51 years (range 25–64), male/female ratio 32/20 (61.5%/38.5%).Twenty-seven out of 31 elderly patients (87,1%) were treated with conformal radiotherapy (CRT, 5940 cGy, 180 cGy/day; CTV2: tumor bed + residual tumor if present + oedema, 3960 cGy; CTV1: tumor bed + residual tumor if present + margins, 1980 cGy). Four out of 31 patients received an intensification dose of xxxx cGy by stereotactic conformal radiotherapy (SRT, 12,9%); among the younger patients, 25/52 were treated with CRT (48,1%) and 27/52 with SRT (51,9%). Concomitant and adjuvant chemotherapy was administered by temozolomide (TMZ).Toxicity was evaluated according to RTOG score. Survival analysis were performed using Kaplan-Meier method and log-rank testing was used for comparison of groups. Results: In the elderly group, neurological acute toxicity was observed in 6/31 patients (19,4%), with grade 3 in two patients. In the under 65 group, 5/52 patients (9,6%) had neurotoxicity (Grade 3 in two patients).This difference was not statistically different.At a median follow-up period of 28 months (range, 3–61), median progression-free survival (PFS) was 11 months in the ≥65 group and 10 months in the under 65 group; median overall survival (OS) was respectively 17 months and 22 months. 1- year survival was respectively 77.6% and 74.5%. Conclusions: In our analysis age did not seem to be a limiting factor in the choice of the therapeutic strategy for patients with glioblastoma multiforme.

No significant financial relationships to disclose.

Correlation between Provoked Ictal SPECT and Depth Recordings in Adult Drug-Resistant Epilepsy Patients

PURPOSE

To correlate ictal hyperperfusion single-photon emission computed tomography (SPECT) area during provoked seizures to the epileptogenic zone (EZ), as defined by depth recordings in adult drug-resistant patients.

METHODS

We included in the study eight drug-resistant epilepsy patients, subjected to both noninvasive and invasive (stereo-electroencephalography, SEEG) presurgical evaluation in the Epilepsy Surgery Center of the Catholic University in Rome, from 2001 to 2003. All patients were subjected to interictal and provoked ictal SPECT scans during scalp video-EEG monitoring. The ictal hyperperfusion area assessed by visual image analysis and, when possible, by statistical parametric mapping (SPM), was compared with the EZ, as assessed by SEEG, to define whether they colocalized.

RESULTS

For each provoked seizure, we obtained a SPECT hyperperfusion area. In five patients, the SPECT hyperperfusion area was included in the EZ as assessed by SEEG. The effectiveness of provoked SPECT was confirmed by comparison with SEEG data, SPM analysis (four patients), and spontaneous ictal SPECT (two patients). Our data were obtained in adult drug-resistant epilepsy patients whose EZ was either located in or extended to extratemporal regions in all but two patients.

CONCLUSIONS

Provoked ictal SPECT confirmed its efficacy and accuracy in the presurgical evaluation because of the colocalization to the EZ. Although the low number of patients precluded any statistical correlation with the surgical outcome, it is worth pointing out that the five patients in whom the hyperperfusion area was included in the EZ showed very satisfactory results.

Effect of vagal nerve stimulation on systemic inflammation and cardiac autonomic function in patients with refractory epilepsy

OBJECTIVE

Recent data suggest that vagus nerve stimulation (VNS) can inhibit cytokine release by inflammatory cells. Accordingly, an association between impaired cardiac parasympathetic function, as assessed by heart rate variability (HRV), and increased markers of inflammation has recently been reported. In this study we assessed the effect of direct left VNS on inflammatory markers and HRV in patients with refractory epilepsy.

METHODS

A 24-hour electrocardiogram Holter recording was performed both at baseline and after 3 months of left VNS in 8 patients (age 32 +/- 24 years, 2 men) who underwent implantation of a VNS device because of refractory epilepsy. Tumor necrosis factor-alpha, interleukin-6 and C-reactive protein serum levels were measured, as markers of inflammation, at the same times.

RESULTS

No significant changes were found after 3 months of left VNS, compared to baseline, both for HRV variables and inflammatory markers. Also, no consistent correlation could be demonstrated between HRV parameters and inflammatory markers in these patients.

CONCLUSIONS

Our data in epileptic patients without cardiovascular disease failed to show a significant effect of left VNS on cardiac autonomic function and on systemic inflammation at short-term follow-up.

Short and middle-latency Median Nerve (MN) SEPs recorded by depth electrodes in human pre-SMA and SMA-proper

OBJECTIVE

To analyse waveforms, latencies and amplitudes of Median Nerve (MN) SEPs recorded by stereotactically electrodes implanted in the SMA of 14 epileptic patients (9 in pre-SMA,3 in SMA-proper, 2 in both) in order to evaluate which short and middle-latency SEPs are generated in this area and which could be the physiological relevance of these responses.

METHODS

Short and middle-latency MN SEPs were recorded by chronically implanted electrodes in the fronto-temporal cortex and in particular in the mesial frontal region of 14 drug-resistant epileptic patients. MN stimulations of 100 micros were delivered by skin electrodes at the wrist; stimulus intensity was adjusted slightly above the motor threshold.

RESULTS

The main result of this study is that middle-latency SEPs were originated in pre-SMA but not in SMA-proper as demonstrated by both referential and bipolar recordings. In particular off-line computed bipolar traces between neighbouring contacts implanted in the pre-SMA and in the frontal external regions showed a phase reversal at the deepest contacts located in pre-SMA. Conversely, bipolar recordings between neighbouring contacts implanted in the SMA-proper and in the frontal external regions showed inversion recovery at more superficial contacts, implanted in area 6. Finally, we confirmed that no short-latency MN SEP (and in particular the N30) is originated in the whole SMA.

CONCLUSIONS

Among premotor areas, somatosensory inputs seem to reach pre-SMA and area 6 but not SMA-proper.

SIGNIFICANCE

This study assessed that no scalp SEP in the first 100 ms after MN stimulus could be generated in SMA-proper.

Unusual ipsilateral hyperkinetic automatisms in SMA seizures

PURPOSE

To describe repetitive movements of the right arm possibly originating from the ipsilateral SMA area in two drug-resistant epileptic patients.

METHODS

Two epileptic patients (one female, one male, 35 and 36 years old, respectively) were submitted to pre-surgical evaluation including history, neurological examination, long-term video-EEG monitoring, interictal and ictal SPET, MRI and fMRI, neuropsychological assessment. Invasive recordings (stereoelectroencephalography) were also performed.

RESULTS

In both patients ictal semiology was characterized by very stereotyped repetitive right arm movements, i.e. tapping towards the thorax (movement rate of 6-7 Hz and 3-4 Hz for the two subjects, respectively). Seizures in the first patient, whose epilepsy was cryptogenetic, originated from the right pre-SMA area, which was surgically removed. She is seizure free 2 years after the operation. In the second patient, in whom a right pre-frontal post-abscess porencephaly was disclosed, the epileptogenic zone included the lesion and surrounding areas, while the SMA area was involved less consistently.

CONCLUSIONS

Even if, according to literature, SMA epilepsy is predominantly characterized by postural manifestations, ipsilateral repetitive movements could be a relevant sign in this kind of epilepsy, as showed in our first patient. The presence of similar semiology in the second patient, might suggest that the symptomatogenic zone involved SMA area.

Retrospective analysis of variables favouring good surgical outcome in posterior epilepsies

AIM

to determine variables favouring good surgical outcome in posterior epilepsies.

METHODS

Fourteen patients submitted to epilepsy surgery were included in the study. The epileptogenic zone was located in temporo-parieto-occipital areas as assessed by both invasive and non-invasive pre-surgical evaluation. Several variables (age at first seizure; age at surgery; disease duration; type, frequency and clinical semiology of seizures; presence of lesion; scalp ictal and interictal EEG; localization and extension of epileptogenic zone; completeness of surgical resection) were compared (Fisher's exact test) with freedom from seizures to determine whether surgical outcome (Engel's classification) could be related to any of them.

RESULTS

Seven patients were seizure free (Ia) and very satisfying results were obtained for 3 patients (2 Ib, 1 Ic). New post-surgical visual deficits occurred only in 3 patients. Surgical outcome was related significantly to two variables: scalp ictal EEG (focal versus non-focal; p: 0.014) and completeness of surgical resection of epileptogenic zone (p: 0.0023). A significant trend towards a better outcome for focal interictal intracranial activity versus a non-focal one (p: 0.07) was found.

CONCLUSIONS

The correlation between completeness of epileptogenic zone resection and surgical outcome suggests that a presurgical protocol, allowing a precise definition of the area of resection, could help in obtaining more satisfying results in posterior epilepsies.

Effects of vagus nerve stimulation on cortical excitability in epileptic patients

Vagus nerve stimulation (VNS) is used as adjunctive treatment for medically refractory epilepsy, but little is known about its mechanisms of action. The effects of VNS on the excitatory and inhibitory circuits of the motor cortex were evaluated in five patients with epilepsy using single- and paired-pulse transcranial magnetic stimulation (TMS). Patients were examined with the stimulator on and off. VNS determined a selective and pronounced increase in the inhibition produced by paired-pulse TMS with no effects on the excitability by single-pulse TMS.

Parietal generators of low- and high-frequency MN (median nerve) SEPs: data from intracortical human recordings

OBJECTIVE

To identify low and high-frequency median nerve (MN) somatosensory evoked potential (SEP) generators by means of chronically implanted electrodes in the parietal lobe (SI and neighbouring areas) of two epileptic patients.

METHODS

Wide-pass short-latency and long-latency SEPs to electrical MN stimulation were recorded in two epileptic patients by stereotactically chronically implanted electrodes in the parietal lobe (SI and neighbouring areas). To study high-frequency responses (HFOs) an off-line digital filtering of depth short-latency SEPs was performed (500-800 Hz, 24 dB roll-off). Spectral analysis was performed by fast Fourier transform.

RESULTS

In both patients we recorded a N20/P30 potential followed by a biphasic N50/P70 response. A little negative response in the 100 ms latency range was the last detectable wide-pass SEP in both patients. Two HFOs components (called iP1 and iP2) were detected by mere visual analysis and spectral analysis, and were supposed to be originated within the parietal cortex.

CONCLUSIONS

This was the very first study that recorded wide bandpass and high frequency SEPs by electrodes, exploring both the lateral and the mesial part of the parietal lobe and particularly that of the post-central gyrus.

Different neuronal contribution to N20 somatosensory evoked potential and to CO2 laser evoked potentials: an intracerebral recording study

OBJECTIVE

To investigate the possible contribution of the primary somatosensory area (SI) to pain sensation.

METHODS

Depth recordings of CO2 laser evoked potentials (LEPs) and somatosensory evoked potentials (SEPs) were performed in an epileptic patient with a stereotactically implanted electrode (Talairach coordinates y=-23, z=40) that passed about 10 mm below the hand representation in her left SI area, as assessed by the source of the N20 SEP component.

RESULTS

The intracerebral electrode was able to record the N20 SEP component after non-painful electrical stimulation of her right median nerve. The N20 potential showed a phase reversal in the bipolar montage (at about 31 mm from the midline), which confirms that the electrode was located near its generator in area 3b. In contrast, no reliable response was recorded from the SI electrode after painful CO2 laser stimulation of the right hand. An N2-P2 response was evoked at the vertex electrode (Cz), thus demonstrating the effectiveness of the delivered CO2 laser stimuli.

CONCLUSIONS

Since the N20 SEP component originates from the anterior bank of the post-central gyrus (area 3b), our result suggests that this part of SI does not participate in LEP generation. In fact, the previously published LEP sources in the SI area estimated from scalp recordings are about 10-17 mm posterior of the electrode in our patient, suggesting that they are more likely located in area 1, 2 or posterior parietal cortex.

The human supplementary motor area-proper does not receive direct somatosensory inputs from the periphery: data from stereotactic depth somatosensory evoked potential recordings

Somatosensory evoked potentials to median nerve (MN) stimulation were recorded by stereotactically implanted electrodes in the frontal lobe of two epileptic patients in order to evaluate whether short-latency cortical responses could be generated in the supplementary motor area (SMA)-proper. In both patients two potentials, called P20 and N30 responses, showed a decreasing amplitude from the most superficial to the deepest contacts and were recorded in the white as well in the grey matter of the frontal lobe. Furthermore, no phase reversal of both P20 and N30 potentials was identifiable along electrode trajectories. Our results suggest that short-latency somatosensory evoked responses recorded in the SMA-proper contralateral to MN stimulation are volume conducted from remote cortical generators.

Ictal brain SPET during seizures pharmacologically provoked with pentylenetetrazol: a new diagnostic procedure in drug-resistant epileptic patients

Functional brain imaging plays an important role in seizure focus localisation. However, truly ictal single-photon emission tomography (SPET) studies are not routinely performed owing to technical problems associated with the use of tracers and methodological and logistical difficulties. In this study we tried to resolve both of these issues by means of a new procedure: technetium-99m ethyl cysteinate dimer (ECD) brain SPET performed during seizures pharmacologically provoked with pentylenetetrazol, a well-known central and respiratory stimulant. We studied 33 drug-resistant epileptic patients. All patients underwent anamnestic evaluation, neuropsychological and psychodynamic assessment, magnetic resonance imaging, interictal and ictal video-EEG monitoring, and interictal and ictal SPET with (99m)Tc-ECD. In order to obtain truly ictal SPET, 65 mg of pentylenetetrazol was injected every 2 minutes and, immediately the seizure began, 740 MBq of (99m)Tc-ECD was injected. The scintigraphic findings were considered abnormal if a single area of hyperperfusion was present and corresponded to the site of a single area of hypoperfusion at interictal SPET: the "hypo-hyperperfusion" SPET pattern. In 27 of the 33 patients (82%), interictal-ictal SPET showed the hypo-hyperperfusion SPET pattern. Video-EEG showed a single epileptogenic zone in 21/33 patients (64%), and MRI showed anatomical lesions in 19/33 patients (57%). Twenty-two of the 27 patients with hypo-hyperperfusion SPET pattern underwent ablative or palliative surgery and were seizure-free at 3 years of follow-up. No adverse effects were noted during pharmacologically provoked seizure. It is concluded that ictal brain SPET performed during pharmacologically provoked seizure provides truly ictal images because (99m)Tc-ECD is injected immediately upon seizure onset. Using this feasible procedure it is possible to localise the focus, to avoid the limitations due to the unpredictability of seizures, to avoid pitfalls due to late injection, to avoid intracranial EEG recording and to minimise costs. The clinical value of our method is confirmed by the good outcome after 3 years of follow-up in those patients submitted to ablative or palliative surgery.

Neurosurgery at the Catholic University in Rome

Neurosurgery at the Catholic University in Rome was initiated by Gian Franco Rossi in 1969 and has gradually expanded since then. From the beginning, research has been regarded as an essential part of training and daily activities in the university's neurosurgery programs. The professional and research education of all faculty members includes at least 1 year abroad in a reputable neurosurgical center. Subspecialization is encouraged. Today, the faculty is composed of 3 full professors, 4 associate professors, and 16 assistant professors. The university's neurosurgery programs include the Institute of Neurosurgery, the residency program, and the following clinical units: a Division of General Neurosurgery; three subspecialty sections comprising Neurotraumatology, Pediatric Neurosurgery, and Functional and Spine Surgery; a day hospital; and dedicated laboratories. More than 1700 surgical patients are treated annually. Epilepsy, pain management, parkinsonism, spinal cord and vertebral pathologies, clinical and basic neuro-oncology, cerebrospinal fluid and intracranial pressure dynamics, cerebrovascular disease, neurotrauma, developmental malformations, and peripheral and central nervous system neuroregeneration are the main fields of clinical and research activities. The results of the research performed thus far at the Catholic University in Rome have been reported in more than 900 publications, most of which have appeared in prominent journals and books. Members of the faculty are involved in relevant editorial activities and serve as officers of national and international scientific and professional societies. In 1999, Giulio Maira succeeded Dr. Rossi in directing the Institute of Neurosurgery and the Division of General Neurosurgery. In addition to the history of neurosurgery at the Catholic University in Rome, this article describes present challenges and plans for the future in neurosurgery at the university.

Factors of surgical outcome in tumoural epilepsy

OBJECTIVES

The purposes of the study were the assessment of the role of surgery in the suppression of epilepsy due to low-grade primitive cerebral tumours and the search for factors relevant to the surgical outcome.

PATIENTS AND METHODS

Forty-eight patients with epilepsy due to low-grade supratentorial cerebral tumours were considered. They presented drug-resistant daily to monthly seizures since for least one year (mean 7 yrs). Twenty-four patients underwent a combined tumour and epileptogenic zone resection ("epilepsy surgery") and 24 tumour resection alone ("lesionectomy"). The surgical outcome was evaluated two years after surgery. Several variables related to the characteristics of the epilepsy, the tumour and surgery, were considered for a possible association with the outcome. Statistical analyses were performed.

RESULTS

Seizure freedom, including aura, was obtained in 35 patients (72.9%). Mild permanent complications occurred in 6 cases. Seizure suppression was significantly associated with complete tumour resection (post-surgical CT or MRI) and relatively low presurgical seizure frequency; it was also related, though not significantly, to small tumour size and histological grade I. The surgical outcome was only slightly better following "epilepsy surgery" than "lesionectomy". However: i) the extent of tumour resection was not relevant regarding the "epilepsy surgery" outcome, while significantly influencing the outcome after "lesionectomy"; ii) the presurgical frequency of seizures and, to a less extent, the tumour size, had a higher influence on the outcome after "lesionectomy".

CONCLUSION

Long-lasting and drug-resistant epilepsy due to cerebral tumours can be suppressed surgically in the majority of cases. The extent of tumour resection and the frequency of the seizures are the most relevant prognostic factors. Both "epilepsy surgery" and "lesionectomy" can provide good results. However, the two approaches should not be regarded as interchangeable: a choice of the approach based on the characteristics of seizures and of the tumour appears relevant to improve the surgical prognosis.

Callosotomy for drug resistant generalized seizures

We report our series of drug resistant epileptic patients submitted to callosotomy. The 25 patients were affected by severe epilepsy with invalidating generalized seizures with fall, lacking of indication for ablative surgery. Nineteen patients, with at least 1 year of follow-up, were considered for this study. The surgical outcome was classified as: class A), seizure disappearance; class B) 80%, class C) 80-50%, class D) less than 50% seizure reduction; E) increase of seizure frequency. The follow-up analysis shows that the better results are obtained with the generalized seizures, in particular the GTA. Our surgical results are discussed considering the data of the literature: about the functional anatomy of the Corpus Callosum, the experimental studies and the clinical series published on callosotomized epileptic patients.