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July2007 Vol.44 Issue:      2 Table of Contents
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Selective Amygdalohippocampectomy for Temporal Lobe Epilepsy Management

Hassan Salama1,2, Ahmed Azab2, Hesham Ben-Khayal1, Hassan Hosny1,3, Peter Vorkapic1,4

Departments of Neurology, Sebea Hospital, Tripoli1; Neurology, Mansoura University2;

Neurology, Cairo University3; Neurosurgery, Hanover University4



ABSTRACT

Epilepsy surgery has a proven treatment effect on patients with medical intractable partial seizures, presumably through its resection of epileptogenic zone. This prospective and nonrandomized controlled study examines whether minimal invasive microneurosurgical interventional through frontolateral trans-sylvian approach for a high selective amygdalohippocampectomy would reduce the frequency of epilepsy and antiepileptic drugs (AEDS), for patients who have had long history of poor response on pharmacotherapy, via measuring over one year the clinical, activity of daily living and EEG outcomes. Our inclusion/ exclusion criteria for selected cases and according to the definition of ILAE are, intractable temporal lobe epilepsy (TLE) either right or left side origin, all patients had a history of  treatment for more than 13 years by AEDS polytherapy and according to our inclusion criteria they should have at least 4 seizures a month. Selective amygdalohippocampectomy was done for 17 patients and all of them were followed up for one year. The study confirmed that selective amygdalohippo-campectomy reduces the seizures frequency and drugs doses in patients with mesial temporal lobe epilepsy (MTS). However, amygdalohippocampectomy did not signify cessation of all AEDS, but all patients showed satisfactory seizure free outcome under monotherapy. There is also significant difference in epilepsy frequency postoperatively especially psychomotor component. The findings are important for the understanding of selective amygdalohippocampectomy role in the treatment of intractable TLE (MTS) with or without secondary generalization.

(Egypt J. Neurol. Psychiat. Neurosurg., 2007, 44(2): 615-622)

 




INTRODUCTION

 

Epilepsy is a common disease of the central nervous system (CNS) with a presumed idiopathic etiology. Despite the incidence and prevalence of epilepsy are 0.6-0.7/1000 and 5-7/1000 respectively, Male/female ratio is 2 to 1, Children/adult 4/1, common among low socioeconomic standard populations and prognosis of recurrence rate after first seizure within 3 years is 50% especially with remote symptomatic seizures, this rate is increasing with duration to 70% after 7 years for idiopathic versus 30% of seizures due to acute illness, the epileptogenesis of partial epilepsy is still obscured1,2.

Nevertheless, about 55% of patients with epilepsy experience complex partial seizures, 45% of them will have medically refractory seizure disorders3,4.

Treatment options of epilepsy are pharmacotherapy, surgery and vagus nerve stimulation. The surgery goals are freedom from seizures; participation and being productive members of society and absence of medications side effects as well as improving of daily activities such as employment, schooling, driving, independency and freedom from social stigmatization5-7.

Surgery should be considered in patients with partial epilepsy after adequate trials of 2-3 good AEDS for 3 years as a minimum. Also the type of epilepsy, focus location, and initial testing may influence this decision. This good selection is essential for satisfactory postoperative clinical outcome and may be of value in our attempt to monitor the disease progression and treatment effects in epilepsy. This study was undertaken to evaluate whether selective amygdalohippocampectomy may have synergistic properties when combined with monotherapy AED, by detecting the changes in frequency of seizures and daily activities for short term follow up outcomes2,8.

 

PATIENTS AND METHODS

 

Seventeen patients, who clinically had complex partial seizures with temporal lobe focus which uncontrolled under polytherapy of AEDS, were included in this study. The clinical characteristics of the patients, as well as the common AEDS used, are shown in table (1) and figure (1 a & b).

These patients were not treated with any drugs which can provoke epilepsy at least six months prior to the study. Patients were compliant for common AEDS with the highest tolerable doses for 6 months prior to surgery but all of them were refractory to these drugs. In this study, presurgical evaluation of all patients included full history taking, thorough clinical examination, probable area of seizure onset in clinical course, long term EEG recording (wake with provocative maneuvers included photic stimulation, hyperventilation & sleep deprivation) and MRI (T1, T2, FLAIR and IRS) with thin coronal cuts through temporal lobes (Figs. 2, 3, 4, 5, 6, 7) (Table 2).

These different modalities of presurgical investigations were selected based on the concordance concept of interictal EEG findings, ictal semiology, MRI and ictal EEG onset that showed convergence to the actual temporal focus zone but if a contradictory or unclear picture emergences, additional testing was warranted and the patient was excluded from this study. Generally speaking, MRI-negative epilepsy patients have poor postoperative outcome even after intensive workup using other modalities (Figs. 2, 3, 4, 5, 6, 7) 7-10.

All patients, individually, were informed preoperative about the likelihood of an excellent outcome and what adverse effects may occur. Postoperative follow up was done every week for the first month and every month for one year8,11.

Measurements of postoperative outcomes were assessed through full history of any symptoms which denoted aborted or full seizures specially isolated auras, control MRI brain, and long term EEG with provocative maneuvers. The AED monotherapy (mostly full dose of carbamazepine) was given for all patients5,10,11.


 

Table 1. Demographic data and clinical characteristics of patients.

 

Group     n        Rt/Lt     Common AEDS         Age              Sex            duration (yr)       PSF (m)       NPA

MTS       17       11/6       Phenytoin                28.5±3.49    10F/7M       17.7±3.1              7.82±1.59   5ND/2D

                                       Carbamazepine

                                       Phenobarbitone

                                       Valporate

                                       Topramate

                                       Lamotrigine

                                       Clonazepam

PSF= Preoperative seizure frequency a month, Rt/Lt= right to left temporal lobe focus site, m= month

Neuropsychological assessment, 2 patients (11.7%) showed mild verbal memory deficit mainly naming and 5 patients (29.4%) have mild nonverbal memory deficit mainly places and abstract design.

 

 

Fig. (1):  A. Showed gender and epilepsy focus location either right or left temporal lobe,

B. Showed the mean age and epilepsy mean duration.

 

Table 2. Presurgical baseline investigations.

 

Group. MTS (n=17).

Past history of febrile convulsions, 10 cases (58.8%)

Family history of epilepsy, 4 cases (23.5%)

History of infrequent secondary generalization, 6 cases (35.2%)

Medical therapy intractability. All patients had uncontrolled epilepsy under polytherapy

Auras, the commonest and most frequent aura for each patient was the epigastric aura (52.9%), psychic symptom such as fear (23.5%), olfactory (11.7%), gustatory sensation one case and one case presented by nonspecific generalized paraesthesia.

Medical & neurological examination. All patients were free of serious medical or neurological signs apart from epilepsy

Psychiatric & psychological evaluations. Patients with history of psychotic, depression symptoms or low IQ (lees than 70) were excluded, frontal executive skills, memory of verbal and nonverbal, attention, visuo-spatial skills and language.

Long term EEG. All patients showed clear cut unilateral EEG epileptiform discharges of temporal lobe origin.

MRI (T1, T2, FLAIR, IRS). Radiological findings are concordant with mesial temporal sclerosis

Functional imaging HMPAO-SPECT. This image was done for one patient who had unsatisfactory MRI findings and confirmed by SPECT study

Patients counseling. All patients were informed about the benefits and surgical complications during and after surgery.

 

 


RESULTS AND DISCUSSION

 

Preoperative seizure frequency was significantly elevated in selected TLE patients, even though there were considerable influences on the levels of daily activities, as shown in figure (1). The serum levels of common AEDS were done and showed ideal therapeutic levels which symbolized compliant patients (data not shown)1,2.

Anyhow, baseline neuropsychological evaluations confirmed that 2 patients out of 17 (11.7%) have mild verbal memory deficit mainly naming and 5 patients (29.4%) have mild nonverbal memory deficit mainly places and abstract design10,12,13.

The study revealed that surgical treatment with selective amygdalohippocampectomy significantly reduced the frequency of seizures up to seizure free specially isolated auras for the whole follow up period (12 months) (no seizure was recorded at month 12 for all patients). In contrast, the patients who have had close similar clinical and investigational findings and refused surgery (12 patients) for personal causes, showed insignificant reduction of seizure frequency with best therapeutic AEDS polytherapy for the same period (data not shown)12,14.

Postoperative neuropsychological evaluations added no more deterioration apart from one patient who developed more deterioration of naming and attention and another one who started to complain of difficulty in places recognition. By the way both patients had abnormal neuropsychological baseline preoperative12,14,15.

All patients continued postoperatively on AED monotherapy by full dose and the majority of our patients received carbamazepine which increases the seizures freedom for all patients at the end of the 12-month study, even though the combination therapy gave the impression that behavioral and social interaction showed good improvement. Furthermore, it was demonstrated for the first time that with minimal invasive microneurosurgical intervention through frontolateral trans-sylvian approach for a high selective amygdalohippocampectomy and with meticulous preoperative selection in patients who have a long history of epilepsy, postoperative complications (such as permanent dysphasia, major memory defect, superior quadrantanopia, behavior and psychotic changes) were passed up13,14.

Although this study showed a reasonable postepilepsy surgery outcome, it has some limitations such as the small number of patients, short term follow up and the limited clinical assessment. Further investigations with a large sample size and in controlled clinical trials are needed to address the surgical efficacy issues as well as to confirm whether the assessment of outcomes is relevant with TLE patients in the evaluation of the treatment protocols in future12.

 

Fig. (2): Preoperative left side hippocampal atrophy on coronal T1-weighted post-GAD enhancement image. B, coronal post-GAD T1-weighted image after selective amygdalohippocampectomy.

 

 

Fig. (3): A, Preoperative right side hippocampal atrophy on coronal T2-weighted image. B, Axial T2-weighted image after selective amygdalohippocampectomy. C & D, Surgical exposure of right hippocampal region.

 

 

Fig. (4): A, Preoperative left side hippocampal atrophy on coronal T2-weighted image.

B, Axial T2-weighted image after selective amygdalohippocampectomy.

 

 

 

Fig. (5): EEG trace showed focal interical epileptiform discharge. Lateralized temporal spike and slow wave complex with phase reversal at the T6 electrode and a field that includes the T4 electrode are seen in right temporal lobe region.

 

 

Fig. (6): Lateralized temporal spike and slow wave complex with phase reversal at the T3 electrode and a field that includes the F7 and T5 electrodes are seen in left temporal lobe region.

 

 

Fig. (7): Lateralized temporal spike and slow wave complex at the T5 electrode and a field that includes the T3 electrode are seen in left temporal lobe region.


REEFRENCES

 

1.      Apuzzo MLJ, Ed. Neurosurgical Aspects of Epilepsy. Park Ridge, Illinois: American Association of Neurological surgeons. 1991

2.      Engel J. Jr, Shewmon DA: Overview: who should be considered a surgical candidate|? In Engel J. Jr, Ed. Surgical Treatment of the Epilepsies, 2nd edition. New York: Raven press: 1993.

3.      Yeh HS, Tew JM, Gartner M. Seizure control after surgery on cerebral arteriovenous malformation. J Neurosurgery. 1993: 78: 12-18.

4.      Palmini A, Andermann F, Olivier A, Tampieri D, Robitaille Y. Focal neuronal migration disorders and intractable partial epilepsy: results of surgical treatment. Ann neurol 1991: 30: 357-364.

5.      Bien CG, Kurthen M, Baron K, et al. long term seizure outcome and antiepileptic drug treatment in surgically treated temporal lobe epilepsy patients: a controlled study. Epilepsia, 2001. 42: 1416-21. PMID: 11879344.

6.      Wieser HG, Elger CE, Eds. Presurgical Evaluation of Epileptics: Basics, Techniques, Implications. Berlin: Springer-Verlag: 1987.

7.      Spencer SS. The relative contributions of MRI, SPECT and PET imaging in epilepsy. Epilepsia 1994: 35 (suppl 6): S72-S89.

8.      Wieser HG. Selective amygdalohippocampectomy: indications, investigative technique and results. In: L Symon, J Brihaye, B Guidetti, et al, Eds. Advances and Technical Standards in Neurosurgery, vol. 13. Vienna: Springer-Verlag: 1986: 39-133.

9.      Jackson GD, Connelly A, Cross JH, Gordon I, Gadian DG. Functional magnetic resonance imaging of focal seizures. Neurology, 1994: 44: 850-856.

10.    Cendes F, Li LM, Watson C, et al. Is ictal recording mandatory in temporal lobe epilepsy? Not when the interictal electroencephalogram and hippocampal atrophy coincide. Arch Neurol, 2000. 57: 497-500.

11.    Antel SB, LiLM, Cendes F, et al. Predicting surgical outcome in temporal lobe epilepsy patients using MRI and MRSI. Neurology, 2002: 28: 1505-12.

12.    Gleibner U, Helmstaedter C, Schramm C, et al. memory outcome after selective amygdalohippocampectomy: a study in 140 patients with temporal lobe epilepsy. Epilepsia, 2001. 43: 87-95.

13.    Lutz MT, Clusmann H, Elger CE, et al. Neuropyscholgical outcome after selective amygdalohippocampectomy with trans-sylvian versus transcortical approach: a randomized prospective clinical trial of surgery for temporal lobe epilepsy. Epilepsia, 2004. 45: 809-16.

14.    Wiebe S, Blume WT, Girvin JP, et al. A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med, 2001. 345: 311-18.

15.    Hajek M, Wieser H-G. Experimental, mainly frontal epilepsies: surgical results. J Epilepsy 1988: 1:103-119.


 

الملخـص العربى

 

الاستئصال الانتقائي لللأميجدالوهبوكمبس في علاج صرع الفص الصدغي

 

الهدف من هذا البحث دراسة وتقييم العلاج الجراحي لمرضى الصرع الجزئي الناتج عن خلل وظيفي وتكويني للفص الصدغي في المخ وذلك تبعا للمظهر الاكلينيكى ووصف النوبات الصرعية , التاريخ المرضى, رسم المخ الكهربائي لفترة طويلة , البحث السيكولوجي الاكلينيكى, الأشعة بالرنين المغناطيسي مع اخذ مقاطع ذات سمك رفيع على الفص الصدغي وذلك لمعرفة التغير التركيبي في هذا الجزء من المخ.

وقد احتوى هذا البحث على سبع عشر مريضا يعانون من هذا النوع من الصرع ذو العلاقة بالأميجدالوهبوكمبس في الفص الصدغي وبعد التأكد من وجود بؤرة صرعية في هذا الجزء تم استئصاله جراحيا.

وقد أظهرت النتائج بعد عام كامل من المتابعة وجود تحسن تام وعدم إصابة المرضى مرة أخرى بنوبات صرع جزئية أو كلية مع إعطاء المرضى دواء واحد فقط بالرغم من التاريخ العلاجي لهم الذي يحتوى على العديد من الأدوية المضادة للصرع وعدم استجابة المرضى لهذا العلاج الدوائي  الاستجابة المرضية لممارسة حياتهم اليومية. وقد أظهر البحث تحسن المرضى من الناحية الاجتماعية والنشاط اليومي لهم.

ويوصى بهذا النوع من الجراحات لمرضى الصرع الجزئي المركب الناتج عن خلل تكويني في الفص الصدغي من المخ.



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