27
Surgical treatment of epilepsy G. Pendl. P. Grunert, M. Graf. und T. Czecn Department of Neurosurgery. Universityof'Graz, Austria
Seventy pati ent s with intractabl e epilepsy were surgically treated. Thirty-three patients und erwent a stereotactic procedure and in all as a first-stage operation fornicotomy was perforrned. Because of inadequate results in 14 patients, an additional ste reotactic inter-
vention was necessary; the targets were amygdala, thalamus, and Fore l's Hvfleld, an d the final outcome of these pati ent s was 9 (27 %) seizure-free , 19 (58 %) impro ved , and 5 (15 %) unchang ed .In 3 patients a selective amygdalo-hippocampectomy was performed with 2 seizure -free patients and one with improvement. Topectomy in focal epilepsy in 5 patients res ulted in freedom fromseizures in all cases . In 23 patients a lobectomywa s performed; 10 (43 %) were seizures -free, 8 (35 %) were impro ved , and 5 (22 %) were unchanged . In 6 patient s only a pathologieallesion was resected . Our res ults speak in favour of ablative surgery. However, stereotactic ope rations are indicated in cases with secondary gene ralization and dis sipated foei on the dominant
und initial eine Fornicotomie durchg eführt . Wegen unzureich ende r Ergebnisse an 14 Patient en erfolgte eine zusätzliche stereotakti sche Intervention , w obe i die Ziel-
gebiete, die Corpora arnygdala , der Thalamus und das Forel'sche Feld wa ren. 9 dieser Pati enten (27 %) wurde n anfallsfrei, bei 19 Patient en (58 %) kam eszu eine r Besserung und 5 Patient en (15 %) blieb en un verän der t. Bei 3 Patient en wurde eine selektive Amygdalohipp ocampektomie durchgeführt, wobei 2 Pati ent en anfalls freiblie ben und eine r sich verbes serte . Eine Topektomie bei fokaler Epilepsie wurd e bei 5 Pati enten durchgeführt. wobei alle anfallsfrei blieben . Bei 23 Patient en erfolgte eine Lobektomie. 10 von diesen (43 %) wa ren anfallsfre i. 8 (35 %)bes serten sich , 5 (23 %) blieben un ver änd ert. Bei 6 Patienten wurde ausschließlich ein krankhafter Prozeß resez iert. Nach unseren Ergebnissen mu ß man von einem Vort eil der ab lativen chirurg ische n Maßnahmen ausgehen. obwohl stereotaktische Oper ationen in Fällen mit sekundärer Gene ralisierung und verstreuten epileptischen Foci der dominanten Hemisph äre indiziert se in können.
hemisph ere. Key-Wor ds Chirurgische Beh andlung der Epilepsie 70 Patienten mit nich t-m edikam entös ein-
stellba rer Epilepsie wurden chiru rgisch beh and elt. Bei 33 Pat ient en wurde ein ste reotakti scher Zugang gewählt
Introduc tion
For patients with epilepsy who do not respond sa tisfactorily to adequa te medical managernent, surgical treatm ent sh ould be cons idered. The main indication
for surgical interv enti on is intractab le tempora l lobe epilepsies (2). but patient s with focal epilepsy of extrate mporal origin should also be cons idered as candidates for surgical treatm ent , es pecia lly in the presence of intracereb ral lesions , such as slow growing tumou rs. and arterioveno us malformati on s, provided the seizures are the most troublesome sympt oms of the patient's disease.
Neurochirurgia 33 (1990) 27-29 (Supplement I) © GeorgThieme Verlag Stuttgart . New York
Epilepsy - Surgical tr eatm ent - Temp orallobectomy - Ste reotactic treatment - Amygda lotomy - Topectom y - Electrocorticogra phy
Basically, two differ ent surg ical procedures are possible in the tr eatment of focal epilepsy: eithe r th e epileptic focus is eliminated dir ectly by (partial) lobectom y (11), or the pathways from the limbic system and conse quentl y the prop agati on of the epileptic activity is interrupt ed by stereotactic methods (4. 9 , 14. 16). Corpus -callosotomy seems to be beneficial for surgical treatme nt in
medically refractory cases with atonie or primary and primar y with seconda ry tonic-clonic seizures (10, 20). Hernispherectamy is res erved for patient s with se izures in cornbi-
nation with infantil e hemiplegia (12). The success oft he opera tion depend s mostly on the pr eop erative work-up of the clinical sym ptornatology, localization of the epileptic area or zone , and multipli city and lateralization of the seizure onset. Neuroimaging
Downloaded by: Universite de Sherbrooke. Copyrighted material.
Summary
Neurochirurgia 33 (1990)
G. Pendl, P. Grunert, M. Graf, T. Czedi
Stereotactic procedures
9
Good Improved Unchanged
19 5
Total
33 (100%)
(27%) (58%) (15%)
Amygdalohi ppocampectomy 2 1 0
Lesion resection
(67%) (33%)
1 4 1
3 (100%)
(100 %1
techniques ar e now sophisticated (13), but electrophysiological evaluation is still mandatory. Therefore, in cases where th e focus is not clear from the scalp electroencephalography (EEG), invasive diagnostic investigattons, such as Implantation of depth electrod es (2), subdural grids (21), foram en ovale electrodes (18), stereo -EEG (18), and others are necessary prior to ablati ve or ste reotact ic surg ery. This paper will not discuss presurgical evaluation, instead the results of different surgical approaches will be analysed retrospectively. Materials and Methods Seventy pati ents with intra ctable epilepsy wer e operated between 1965 and 1988, the postoperativ e follow-up was between 1 and 23 years. Thirty-thr ee patient s were admitted for stereotactic treatment, in 23 patients a lobectomy was perform ed, 3 patients und erw ent amygdalo-hipp ocamp ectomy, 5 patients had topectomy of th e electrocorticographically defined focus, and in 6 patients only th e direct resection of a path ological lesion was performed (Table 1). The age ofthe patients rang ed from 19 to 47 years Imean , 30 years). In all but 6 patients a consta nt unilat eral temporal focus was recognized from scalp EEG. In these 6 patients path ology activity was over temporal ar eas bilaterally, but pr edomin ant on one side. The stereotactic operations were performed und er local anesthesia, using the Riechert-Mund inger stereotactic system . The ta rget points were calculated from a ventriculography. For stimulation at the tar get point a reetangu lar electric pulse of 1 msec duration, 5-20 mA and subs equently 1,4,2 5.50 and 100 Hz was appli ed. High frequency lesion generator was used for coagulation. In all 23 patients with a lobectomy apreoperative Wada test was performed for ident ification ofthe dominant hernis-
Table 2 Stereotactic operations intemporal lobe epilepsy (n = 33) Procedure
No.01 cases
First step lornicotomy + commissurotomy Second step repeated lornicotomy thalamotomy amygdalotomy Forel's H-tomy Thi rdstep thalamotomy
33 33
14 1 6 5 2
(17%) (67%) (17%1
6 (100%1
phere. Half of these patients und erwent chronic depth EEGrecord ings prior to sur gery. The patients were operated under general ane sthes ia with considerable varia tion in the use of anesth etics. After craniotomy an electrocorticogra phy was perform ed in all patients (6. 7). For electrocorticogra phy stainless steel electrodes with a ball-shaped tip wer e used . Bipolar montages were exclusively employed. The outcome was classified accor ding to Fisher and Uematsu (2).
ResuIts
Forty-eight stereotactic operations wer e performed in 33 patients (Table 1 and 2). As first-step procedure the ipsilatera l fornix and anterior cornmissure wer e transsected in all pati ents. With a drive-out stylet electrode the stria medul laris thalarni could also be reached and interrupt ed. The stimulation effects du ring this pro cedure are shown in Table 3. After these procedures four pati ents wer e completely seizure-free , 22 had a reduced number of seizures , especially reduction of genera lization to tonicclonic seizu res, and seven patients were unchanged. In 14 patients with inadequate res ults a second operation was necessary. The target points were fornix in one case (cornputed tomography scan of this patient showed an incornplete transsection ofthe fornix), medial amygdala in 5 cases, oral pole of the medial thalamic nucleus in 6 cases, and Forel's H-field in 2 cases. After this operation 5 of the 14 patients were seizure-free, 5 improv ed, and 3 unchanged. In one pati ent a thalamotomy was performed as a thirdstag e operation (Table 2). Amygdalo-hippocamp ectomy was perform ed in 3 patients with tem pora l lobe epilepsy without noticeabl e pathology in one case . Two cases had a good outcome and one was improved. In 6 patients with dir ect resection ofthe lesion only the outcome was less satisfactory (Table 1). Twenty-three patients underwent a partial lobectomy. In electrocorticography dissipated spike foei were recorded in 12 cases, a limited spike focus in 7 cases, no cortical spike activity in 2 cases , an d inconclusiv e or minor focus in 2 cases. After partial temporallobectomy 10 patients were seizur e-free, 8 were improved. and 5 were unchanged. The final outcome of all operations is sh own in Table 1. Forel's H-lield
Aura Temporal lobe seizure Vegetativesymptomsonly Contralaterealtonic muscle contractions No elfect
Table 1 Surgical results in 10cal intractable epilepsy(n = 70)
o o o 2 o
Table 3 Stimulation elfects during stereotactic operations (n = 44)
Downloaded by: Universite de Sherbrooke. Copyrighted material.
28
Neu roch iru rgia 33 (1990)
S urgical tre atment 0/ epilep sy
Discussion
The second basic concept in the surgical treatment of temporal lobe epilepsy is the exeision of the epileptic area . After the pioneer work of Först er an d Altenburger (3) and Penfi eld and Ja sper (8l, par tial temp ora l lobectomy has been the most common surgi cal treatm ent of epilepsy in most neuro surgi cal cent ers. The outcome of the lobectomy was impr oved with the intr oduction of chronic depth EEG recordings. Suffieient information about the focus and sprea d of epileptic activity are necessary, espeeially for the evaluation of patients for selective a mygda lohipp ocam pectomy (19). Dur results in the treatment of cases with medically refractory epilepsy favour ablative surgery, especially when the focus is in th e non-dominant hemisphere. Ther e were more "excellent" respond ers in this group than in the stereotaetic group. Furt hermore, in cases with most eircumscribed foei, over 90 % excellent outcomes could be expected (17). The results suggest early recognition of surgical candidates before sprea d of epileptic activity occurs and therefore, radical resections may be necessary as ster eotactic opera tions may not be optimally effective. Open surgical treatm ent with electrocorticogra phy is ind icated in all patients where a lesion, such as tumo ur or arteriovenous malformation , is found by neuroradiological investigation, in order to asse ss the sprea d of epileptic activity. Electrocorticography is used as the ultimate method to delineat e th e focus or zone involved. In case s with uneertainties about location and/o r exte nt of epileptogenic area , presurgical electrophysiological workup is obviously man datory (18). On the othe r hand , we reserve stereotactic procedures for patients with an exte nsive focus (dissipate d spike foeus also in extra tempora l and/ or posterior regions), and in patients with high ineidence of secondary gener alization in the dominant hemisph ere.
References Bouchard, G.: Lengte rm results of ste reotactic forni cotomy and fornicoamygdalotomy in pa tients with temporal lobe epilepsy sh owing behaviora l disturbances. In: Um ba ch. W. (ed.I; Special Topics in Stereotaxis. Hippocr ates , Stuttgart. t 97t . 53 -64 2 Fisher. R. S .. S. Uemats u: Surgi cal therapy of compi ex pa rtial epi lepsy. Johns Hopk ins Med . J . 151 (t 982) 332 -343 3 Först er, 0 .. H. A/ tenburger: Elekt robiologische Vorgän ge an der men schlichen Hirnri nde . Deutsch Z. Nervenbe llk. 135 93 5) 227-288 4 Gang/berger. J. A. : New possibiliti es of ste reot actic tr eatm ent of temp oral lob e epilepsy (TLE). Acta Neurochir. ISuppl.I Wien. 23 (19761211 - 214 5 Ganglberger, J. A . E. Grell-Knapp . M. lI aider: Comput er analysis of electrophysiological p henomena d uring stereo tactical forni co-and a mygdaloto my. ln : Umbach. W. Ied.l: Specia l Topics in Ster eotaxis. Hippocrat es, Stuugart. 1971, 149 - 155 I> Otoor. P.: Contributions of electroencephalography and electrocorticography to the neurosurgical trea tment of the epilepsies. In: Pur pu ra D. P.. J. K. Penry, H. D. Walter Ieds.l: Adva nces in Neurology, Vol. 8 . Raven. New York. t975. 59 - t06 7 Graf. Mo, E. Niede rmev er. J. Schi emann er al.: Electrocorticography - Information dertved from intraoperative recordi ngs during seizu re surgery . Clin. Electr oencephalogr . 15 (1984) 8 3- 9 1 8 Penfield. w.. 11. Jasp er: Epilepsy and the FunctionalAnatomy oft he Human Brain. üttle Brown & Co, Boston. 195 4. t83-280 9 Ramamurthi. B.. S. Ka/yana raman : Stereotactlc targets for e pilepsy. In: Schalterb ran d. G., A. E. Walker Ieds .). Stereota xy of the Human Brai n. GeorgThieme , Stuttga rt , 1982 . 6 53- 660 10 Rappapart. Z. H.. P. Lerman: Corpus callosotomy in the tr eatment of secc ndary generalizing intracta ble epilepsy. Acta Neurochir .. Wien 94 (19881tO- 14 11 Rasmuss en. T.: Cortieal resection for medlcally rcfraetory focal epl lepsy: Resu lts. Iesso ns and questions. In: Ras mus sen , T., R. Marin o (eds.l . Functiona l Neurosurgery . Vol. 9. Raven, New York 19 79. 253 -269 12 Rasmussen. T.: Comme nta ry. Extrate m pora l cortical excis ions a nd hem ispher ectomy. In; Enge l. J . j r (ed .): Su rgical Trea tmen t of thc Epileps ies . Haven. New York, 1987, 41 7 - 4 24 13 Rouqier, A.. J. M. Bis et. P. Kien er al.: IHMet chlru rgte d e l'e pllepsl e . Neurochiru rgie 33 (19881 t 88 -1 9 3 H Spiege/.A. E.. H. T. Wycis . E. G. Szek e/y er al.: Stimulation of'Forel' s fleld during ste reotactic operations in the h uman brain. Electroen ceph . Oin. Neurophysiol. 16 (1964 ) 53 7-548 I S Umbach. W : Long te rm results of forni cotomy for tem po ral epüepsy. In: Spiegel. A. E., H. T. Wycis Ieds.): Advan ces in Stereoencephalotomy, Vol. 2111. Karge r. Basel. 1966. 121-123 16 Walke r. A. E.: Gene ral prin ciples of stereotactlc surgery for epilepsy. In: Schalterbrand. G.. A. E. Walke r (eds.l: Ste reotaxy of the Human Brain . Geo rg Thte me . Stuttgart. 1982 .645-652 17 Wieser. H. G.: Selecüve amygda lö-hippocampecto rny: lndica üc ns. Investtgaüve tech niques and result s. In: L. Symo n: Advan ces a nd Techn ical Sta nd ards in Neurosu rge ry, Vol. 13. Spri nger. Wien, 1985. 39- 133 18 Wieser. H. G.. C. E. Btqer. S. R. G. S todieck : The "fora men ovale electrode". A new recording method for the preopera tive evaluation of patien ts suITering from mesto-ba sal te mporal lobe epilepsy . Electr oenceph. Clin. Neurophysiol. 6 t (198 5) 314-3 22 19 Wiese r. H.. M. Yasa rgi/: Die se lektive Amygd ala hippoca mpekto mie a ls chirurgische Beha ndlungsmethode der medi obasalen limb lsehen Epilepsie . Neuroc hiru rgta. Stuttgart 25 (1982) 39-50 20 Wy llie. E.: Corpus callosotomy for intractab le gen erali zed ep ileps y. J. Pediatr . tt3 (19881 255-261 21 Wyl/i e. E.• H. Lude rs, H. JJ. Marris er al.: Subdural electrod es in the evaluation of epilepsy surgery in childre n and adults . Neuropedla trics 19 (1988 ) 80 - 86 1
ü
G. Pendl. M. D.
Professor and Chairma n Depa rtment of Neu rosu rgery University ofG raz Medica l Sehoo l Auenbruggerp latz 5 A-8036 Gra z, Austria
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The aim ofthe stereotactic trea tment ofte mporal lobe epilepsy is the interru ption of th e propagation of epileptic dischar ges from the mes iolimbic areas . Umbach (15) and Bouehar d (1) report ed favourable effeet of fornieotomy on temp oral lobe seizures. In our series we could confirm their observations. Further, we found an excellent effect of fornic otomy on reducing second ary generalized seizures in temp oral lobe epilepsy. Twenty out of23 patients suffering from additi onal seeondarily genera lized tonicclonic seizure s were be eompletely relieved from the genera lized seizures. Further advantages of fornicotomy are the Iimited operative proeedure and minimal risk of postop erative eomplications. Where forn icotomy is perform ed in the rostroeranial part , commissure anterior, stria medullar is, and stria terminalis ean be interrupted as weU. However , this procedure was notsufficient in all patients. In about one third of the patients a second operation was necessa ry. In th e seeond -stage operation our tar get was the medial amygdala and since 1971 the amygda lothalamic tar get in the oral pole of the medial thalam ic nuclei. The basic concept for a tha lamotomy is due to the obse rvations of Gang/berger et al. (5), who recorded polysynaptic responses over the front al lobe after stimulation of amygdala, which were relayed through the medial thalamu s.
29
Surgical treatment of epilepsy G. Pendl. P. Grunert, M. Graf. und T. Czecn Department of Neurosurgery. Universityof'Graz, Austria
Seventy pati ent s with intractabl e epilepsy were surgically treated. Thirty-three patients und erwent a stereotactic procedure and in all as a first-stage operation fornicotomy was perforrned. Because of inadequate results in 14 patients, an additional ste reotactic inter-
vention was necessary; the targets were amygdala, thalamus, and Fore l's Hvfleld, an d the final outcome of these pati ent s was 9 (27 %) seizure-free , 19 (58 %) impro ved , and 5 (15 %) unchang ed .In 3 patients a selective amygdalo-hippocampectomy was performed with 2 seizure -free patients and one with improvement. Topectomy in focal epilepsy in 5 patients res ulted in freedom fromseizures in all cases . In 23 patients a lobectomywa s performed; 10 (43 %) were seizures -free, 8 (35 %) were impro ved , and 5 (22 %) were unchanged . In 6 patient s only a pathologieallesion was resected . Our res ults speak in favour of ablative surgery. However, stereotactic ope rations are indicated in cases with secondary gene ralization and dis sipated foei on the dominant
und initial eine Fornicotomie durchg eführt . Wegen unzureich ende r Ergebnisse an 14 Patient en erfolgte eine zusätzliche stereotakti sche Intervention , w obe i die Ziel-
gebiete, die Corpora arnygdala , der Thalamus und das Forel'sche Feld wa ren. 9 dieser Pati enten (27 %) wurde n anfallsfrei, bei 19 Patient en (58 %) kam eszu eine r Besserung und 5 Patient en (15 %) blieb en un verän der t. Bei 3 Patient en wurde eine selektive Amygdalohipp ocampektomie durchgeführt, wobei 2 Pati ent en anfalls freiblie ben und eine r sich verbes serte . Eine Topektomie bei fokaler Epilepsie wurd e bei 5 Pati enten durchgeführt. wobei alle anfallsfrei blieben . Bei 23 Patient en erfolgte eine Lobektomie. 10 von diesen (43 %) wa ren anfallsfre i. 8 (35 %)bes serten sich , 5 (23 %) blieben un ver änd ert. Bei 6 Patienten wurde ausschließlich ein krankhafter Prozeß resez iert. Nach unseren Ergebnissen mu ß man von einem Vort eil der ab lativen chirurg ische n Maßnahmen ausgehen. obwohl stereotaktische Oper ationen in Fällen mit sekundärer Gene ralisierung und verstreuten epileptischen Foci der dominanten Hemisph äre indiziert se in können.
hemisph ere. Key-Wor ds Chirurgische Beh andlung der Epilepsie 70 Patienten mit nich t-m edikam entös ein-
stellba rer Epilepsie wurden chiru rgisch beh and elt. Bei 33 Pat ient en wurde ein ste reotakti scher Zugang gewählt
Introduc tion
For patients with epilepsy who do not respond sa tisfactorily to adequa te medical managernent, surgical treatm ent sh ould be cons idered. The main indication
for surgical interv enti on is intractab le tempora l lobe epilepsies (2). but patient s with focal epilepsy of extrate mporal origin should also be cons idered as candidates for surgical treatm ent , es pecia lly in the presence of intracereb ral lesions , such as slow growing tumou rs. and arterioveno us malformati on s, provided the seizures are the most troublesome sympt oms of the patient's disease.
Neurochirurgia 33 (1990) 27-29 (Supplement I) © GeorgThieme Verlag Stuttgart . New York
Epilepsy - Surgical tr eatm ent - Temp orallobectomy - Ste reotactic treatment - Amygda lotomy - Topectom y - Electrocorticogra phy
Basically, two differ ent surg ical procedures are possible in the tr eatment of focal epilepsy: eithe r th e epileptic focus is eliminated dir ectly by (partial) lobectom y (11), or the pathways from the limbic system and conse quentl y the prop agati on of the epileptic activity is interrupt ed by stereotactic methods (4. 9 , 14. 16). Corpus -callosotomy seems to be beneficial for surgical treatme nt in
medically refractory cases with atonie or primary and primar y with seconda ry tonic-clonic seizures (10, 20). Hernispherectamy is res erved for patient s with se izures in cornbi-
nation with infantil e hemiplegia (12). The success oft he opera tion depend s mostly on the pr eop erative work-up of the clinical sym ptornatology, localization of the epileptic area or zone , and multipli city and lateralization of the seizure onset. Neuroimaging
Downloaded by: Universite de Sherbrooke. Copyrighted material.
Summary
Neurochirurgia 33 (1990)
G. Pendl, P. Grunert, M. Graf, T. Czedi
Stereotactic procedures
9
Good Improved Unchanged
19 5
Total
33 (100%)
(27%) (58%) (15%)
Amygdalohi ppocampectomy 2 1 0
Lesion resection
(67%) (33%)
1 4 1
3 (100%)
(100 %1
techniques ar e now sophisticated (13), but electrophysiological evaluation is still mandatory. Therefore, in cases where th e focus is not clear from the scalp electroencephalography (EEG), invasive diagnostic investigattons, such as Implantation of depth electrod es (2), subdural grids (21), foram en ovale electrodes (18), stereo -EEG (18), and others are necessary prior to ablati ve or ste reotact ic surg ery. This paper will not discuss presurgical evaluation, instead the results of different surgical approaches will be analysed retrospectively. Materials and Methods Seventy pati ents with intra ctable epilepsy wer e operated between 1965 and 1988, the postoperativ e follow-up was between 1 and 23 years. Thirty-thr ee patient s were admitted for stereotactic treatment, in 23 patients a lobectomy was perform ed, 3 patients und erw ent amygdalo-hipp ocamp ectomy, 5 patients had topectomy of th e electrocorticographically defined focus, and in 6 patients only th e direct resection of a path ological lesion was performed (Table 1). The age ofthe patients rang ed from 19 to 47 years Imean , 30 years). In all but 6 patients a consta nt unilat eral temporal focus was recognized from scalp EEG. In these 6 patients path ology activity was over temporal ar eas bilaterally, but pr edomin ant on one side. The stereotactic operations were performed und er local anesthesia, using the Riechert-Mund inger stereotactic system . The ta rget points were calculated from a ventriculography. For stimulation at the tar get point a reetangu lar electric pulse of 1 msec duration, 5-20 mA and subs equently 1,4,2 5.50 and 100 Hz was appli ed. High frequency lesion generator was used for coagulation. In all 23 patients with a lobectomy apreoperative Wada test was performed for ident ification ofthe dominant hernis-
Table 2 Stereotactic operations intemporal lobe epilepsy (n = 33) Procedure
No.01 cases
First step lornicotomy + commissurotomy Second step repeated lornicotomy thalamotomy amygdalotomy Forel's H-tomy Thi rdstep thalamotomy
33 33
14 1 6 5 2
(17%) (67%) (17%1
6 (100%1
phere. Half of these patients und erwent chronic depth EEGrecord ings prior to sur gery. The patients were operated under general ane sthes ia with considerable varia tion in the use of anesth etics. After craniotomy an electrocorticogra phy was perform ed in all patients (6. 7). For electrocorticogra phy stainless steel electrodes with a ball-shaped tip wer e used . Bipolar montages were exclusively employed. The outcome was classified accor ding to Fisher and Uematsu (2).
ResuIts
Forty-eight stereotactic operations wer e performed in 33 patients (Table 1 and 2). As first-step procedure the ipsilatera l fornix and anterior cornmissure wer e transsected in all pati ents. With a drive-out stylet electrode the stria medul laris thalarni could also be reached and interrupt ed. The stimulation effects du ring this pro cedure are shown in Table 3. After these procedures four pati ents wer e completely seizure-free , 22 had a reduced number of seizures , especially reduction of genera lization to tonicclonic seizu res, and seven patients were unchanged. In 14 patients with inadequate res ults a second operation was necessary. The target points were fornix in one case (cornputed tomography scan of this patient showed an incornplete transsection ofthe fornix), medial amygdala in 5 cases, oral pole of the medial thalamic nucleus in 6 cases, and Forel's H-field in 2 cases. After this operation 5 of the 14 patients were seizure-free, 5 improv ed, and 3 unchanged. In one pati ent a thalamotomy was performed as a thirdstag e operation (Table 2). Amygdalo-hippocamp ectomy was perform ed in 3 patients with tem pora l lobe epilepsy without noticeabl e pathology in one case . Two cases had a good outcome and one was improved. In 6 patients with dir ect resection ofthe lesion only the outcome was less satisfactory (Table 1). Twenty-three patients underwent a partial lobectomy. In electrocorticography dissipated spike foei were recorded in 12 cases, a limited spike focus in 7 cases, no cortical spike activity in 2 cases , an d inconclusiv e or minor focus in 2 cases. After partial temporallobectomy 10 patients were seizur e-free, 8 were improved. and 5 were unchanged. The final outcome of all operations is sh own in Table 1. Forel's H-lield
Aura Temporal lobe seizure Vegetativesymptomsonly Contralaterealtonic muscle contractions No elfect
Table 1 Surgical results in 10cal intractable epilepsy(n = 70)
o o o 2 o
Table 3 Stimulation elfects during stereotactic operations (n = 44)
Downloaded by: Universite de Sherbrooke. Copyrighted material.
28
Neu roch iru rgia 33 (1990)
S urgical tre atment 0/ epilep sy
Discussion
The second basic concept in the surgical treatment of temporal lobe epilepsy is the exeision of the epileptic area . After the pioneer work of Först er an d Altenburger (3) and Penfi eld and Ja sper (8l, par tial temp ora l lobectomy has been the most common surgi cal treatm ent of epilepsy in most neuro surgi cal cent ers. The outcome of the lobectomy was impr oved with the intr oduction of chronic depth EEG recordings. Suffieient information about the focus and sprea d of epileptic activity are necessary, espeeially for the evaluation of patients for selective a mygda lohipp ocam pectomy (19). Dur results in the treatment of cases with medically refractory epilepsy favour ablative surgery, especially when the focus is in th e non-dominant hemisphere. Ther e were more "excellent" respond ers in this group than in the stereotaetic group. Furt hermore, in cases with most eircumscribed foei, over 90 % excellent outcomes could be expected (17). The results suggest early recognition of surgical candidates before sprea d of epileptic activity occurs and therefore, radical resections may be necessary as ster eotactic opera tions may not be optimally effective. Open surgical treatm ent with electrocorticogra phy is ind icated in all patients where a lesion, such as tumo ur or arteriovenous malformation , is found by neuroradiological investigation, in order to asse ss the sprea d of epileptic activity. Electrocorticography is used as the ultimate method to delineat e th e focus or zone involved. In case s with uneertainties about location and/o r exte nt of epileptogenic area , presurgical electrophysiological workup is obviously man datory (18). On the othe r hand , we reserve stereotactic procedures for patients with an exte nsive focus (dissipate d spike foeus also in extra tempora l and/ or posterior regions), and in patients with high ineidence of secondary gener alization in the dominant hemisph ere.
References Bouchard, G.: Lengte rm results of ste reotactic forni cotomy and fornicoamygdalotomy in pa tients with temporal lobe epilepsy sh owing behaviora l disturbances. In: Um ba ch. W. (ed.I; Special Topics in Stereotaxis. Hippocr ates , Stuttgart. t 97t . 53 -64 2 Fisher. R. S .. S. Uemats u: Surgi cal therapy of compi ex pa rtial epi lepsy. Johns Hopk ins Med . J . 151 (t 982) 332 -343 3 Först er, 0 .. H. A/ tenburger: Elekt robiologische Vorgän ge an der men schlichen Hirnri nde . Deutsch Z. Nervenbe llk. 135 93 5) 227-288 4 Gang/berger. J. A. : New possibiliti es of ste reot actic tr eatm ent of temp oral lob e epilepsy (TLE). Acta Neurochir. ISuppl.I Wien. 23 (19761211 - 214 5 Ganglberger, J. A . E. Grell-Knapp . M. lI aider: Comput er analysis of electrophysiological p henomena d uring stereo tactical forni co-and a mygdaloto my. ln : Umbach. W. Ied.l: Specia l Topics in Ster eotaxis. Hippocrat es, Stuugart. 1971, 149 - 155 I> Otoor. P.: Contributions of electroencephalography and electrocorticography to the neurosurgical trea tment of the epilepsies. In: Pur pu ra D. P.. J. K. Penry, H. D. Walter Ieds.l: Adva nces in Neurology, Vol. 8 . Raven. New York. t975. 59 - t06 7 Graf. Mo, E. Niede rmev er. J. Schi emann er al.: Electrocorticography - Information dertved from intraoperative recordi ngs during seizu re surgery . Clin. Electr oencephalogr . 15 (1984) 8 3- 9 1 8 Penfield. w.. 11. Jasp er: Epilepsy and the FunctionalAnatomy oft he Human Brain. üttle Brown & Co, Boston. 195 4. t83-280 9 Ramamurthi. B.. S. Ka/yana raman : Stereotactlc targets for e pilepsy. In: Schalterb ran d. G., A. E. Walker Ieds .). Stereota xy of the Human Brai n. GeorgThieme , Stuttga rt , 1982 . 6 53- 660 10 Rappapart. Z. H.. P. Lerman: Corpus callosotomy in the tr eatment of secc ndary generalizing intracta ble epilepsy. Acta Neurochir .. Wien 94 (19881tO- 14 11 Rasmuss en. T.: Cortieal resection for medlcally rcfraetory focal epl lepsy: Resu lts. Iesso ns and questions. In: Ras mus sen , T., R. Marin o (eds.l . Functiona l Neurosurgery . Vol. 9. Raven, New York 19 79. 253 -269 12 Rasmussen. T.: Comme nta ry. Extrate m pora l cortical excis ions a nd hem ispher ectomy. In; Enge l. J . j r (ed .): Su rgical Trea tmen t of thc Epileps ies . Haven. New York, 1987, 41 7 - 4 24 13 Rouqier, A.. J. M. Bis et. P. Kien er al.: IHMet chlru rgte d e l'e pllepsl e . Neurochiru rgie 33 (19881 t 88 -1 9 3 H Spiege/.A. E.. H. T. Wycis . E. G. Szek e/y er al.: Stimulation of'Forel' s fleld during ste reotactic operations in the h uman brain. Electroen ceph . Oin. Neurophysiol. 16 (1964 ) 53 7-548 I S Umbach. W : Long te rm results of forni cotomy for tem po ral epüepsy. In: Spiegel. A. E., H. T. Wycis Ieds.): Advan ces in Stereoencephalotomy, Vol. 2111. Karge r. Basel. 1966. 121-123 16 Walke r. A. E.: Gene ral prin ciples of stereotactlc surgery for epilepsy. In: Schalterbrand. G.. A. E. Walke r (eds.l: Ste reotaxy of the Human Brain . Geo rg Thte me . Stuttgart. 1982 .645-652 17 Wieser. H. G.: Selecüve amygda lö-hippocampecto rny: lndica üc ns. Investtgaüve tech niques and result s. In: L. Symo n: Advan ces a nd Techn ical Sta nd ards in Neurosu rge ry, Vol. 13. Spri nger. Wien, 1985. 39- 133 18 Wieser. H. G.. C. E. Btqer. S. R. G. S todieck : The "fora men ovale electrode". A new recording method for the preopera tive evaluation of patien ts suITering from mesto-ba sal te mporal lobe epilepsy . Electr oenceph. Clin. Neurophysiol. 6 t (198 5) 314-3 22 19 Wiese r. H.. M. Yasa rgi/: Die se lektive Amygd ala hippoca mpekto mie a ls chirurgische Beha ndlungsmethode der medi obasalen limb lsehen Epilepsie . Neuroc hiru rgta. Stuttgart 25 (1982) 39-50 20 Wy llie. E.: Corpus callosotomy for intractab le gen erali zed ep ileps y. J. Pediatr . tt3 (19881 255-261 21 Wyl/i e. E.• H. Lude rs, H. JJ. Marris er al.: Subdural electrod es in the evaluation of epilepsy surgery in childre n and adults . Neuropedla trics 19 (1988 ) 80 - 86 1
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G. Pendl. M. D.
Professor and Chairma n Depa rtment of Neu rosu rgery University ofG raz Medica l Sehoo l Auenbruggerp latz 5 A-8036 Gra z, Austria
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The aim ofthe stereotactic trea tment ofte mporal lobe epilepsy is the interru ption of th e propagation of epileptic dischar ges from the mes iolimbic areas . Umbach (15) and Bouehar d (1) report ed favourable effeet of fornieotomy on temp oral lobe seizures. In our series we could confirm their observations. Further, we found an excellent effect of fornic otomy on reducing second ary generalized seizures in temp oral lobe epilepsy. Twenty out of23 patients suffering from additi onal seeondarily genera lized tonicclonic seizure s were be eompletely relieved from the genera lized seizures. Further advantages of fornicotomy are the Iimited operative proeedure and minimal risk of postop erative eomplications. Where forn icotomy is perform ed in the rostroeranial part , commissure anterior, stria medullar is, and stria terminalis ean be interrupted as weU. However , this procedure was notsufficient in all patients. In about one third of the patients a second operation was necessa ry. In th e seeond -stage operation our tar get was the medial amygdala and since 1971 the amygda lothalamic tar get in the oral pole of the medial thalam ic nuclei. The basic concept for a tha lamotomy is due to the obse rvations of Gang/berger et al. (5), who recorded polysynaptic responses over the front al lobe after stimulation of amygdala, which were relayed through the medial thalamu s.
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