Long-term outcome of epilepsy surgery among 399 patients with nonlesional seizure foci including mesial temporal lobe sclerosis

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The authors reviewed the long-term outcome of focal resection in a large group of patients who had intractable partial nonlesional epilepsy, including mesial temporal lobe sclerosis (MTS), and who were treated consecutively at a single institution. The goal of this study was to evaluate the long-term efficacy of epilepsy surgery and the preoperative factors associated with seizure outcome.


This retrospective analysis included 399 consecutive patients who underwent epilepsy surgery at Mayo Clinic in Rochester, Minnesota, between 1988 and 1996. The mean age of the patients at surgery was 32 ± 12 years (range 3–69 years), and the mean age at seizure onset was 12 ± 11 years (range 0–55 years). There were 214 female (54%) and 185 male (46%) patients. The mean duration of epilepsy was 20 ±12 years (range 1–56 years). The preceding values are given as the mean ± standard deviation.

Of the 399 patients, 237 (59%) had a history of complex partial seizures, 119 (30%) had generalized seizures, 26 (6%) had simple partial seizures, and 17 (4%) had experienced a combination of these. Preoperative evaluation included a routine and video-electroencephalography recordings, magnetic resonance imaging of the head according to the seizure protocol, neuropsychological testing, and a sodium amobarbital study. Patients with an undefined epileptogenic focus and discordant preoperative studies underwent an intracranial study. The mean duration of follow up was 6.2 ± 4.5 years (range 0.6–15.7 years). Seizure outcome was categorized based on the modified Engel classification. Time-to-event analysis was performed using Kaplan–Meier curves and Cox regression models to evaluate the risk factors associated with outcomes.

Among these patients, 372 (93%) underwent temporal and 27 (7%) had extratemporal resection of their epileptogenic focus. Histopathological examination of the resected specimens revealed MTS in 113 patients (28%), gliosis in 237 (59%), and normal findings in 49 (12%). Based on the Kaplan–Meier analysis, the probability of an Engel Class I outcome (seizure free, auras, or seizures related only to medication withdrawal) for the overall patient group was 81% (95% confidence interval [CI] 77–85%) at 6 months, 78% (CI 74–82%) at 1 year, 76% (CI 72–80%) at 2 years, 74% (CI 69–78%) at 5 years, and 72% (CI 67–77%) at 10 years postoperatively. The rate of Class I outcomes remained 72% for 73 patients with more than 10 years of follow up. If a patient was in Class I at 1 year postoperatively, the probability of seizure remission at 10 years postoperatively was 92% (95% CI 89–96%); almost all seizures occurred during the 1st year after surgery. Factors predictive of poor outcome from surgery were normal pathological findings in resected tissue (p = 0.038), male sex (p = 0.035), previous surgery (p < 0.001), and an extratemporal origin of seizures (p < 0.001).


The response to epilepsy surgery during the 1st follow-up year is a reliable indicator of the long-term Engel Class I postoperative outcome. This finding may have important implications for patient counseling and postoperative discontinuation of anticonvulsant medications.

Abbreviations used in this paper: AED = antiepileptic drug; ATL = anterior temporal lobectomy; CI = confidence interval; EEG = electroencephalography; MR = magnetic resonance; MTS = mesial temporal lobe sclerosis; SD = standard deviation; SISCOM = subtracted ictal–interictal SPECT coregistered to MR imaging; SPECT = single-photon emission computerized tomography.

Article Information

Address reprint requests to: Aaron A. Cohen-Gadol, M.D., Department of Neurologic Surgery, Joseph 1-229, Saint Mary’s Hospital, 1216 Second Street SW, Rochester, Minnesota 55902. email: acohenmd@gmail.com.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    Kaplan–Meier curve showing the proportion of patients in Engel Class I outcome with time. The inset table presents the number of patients at risk in the three different pathological categories at 1, 2, 5, and 10 years postoperatively.

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    Kaplan–Meier graph showing the proportion of patients in Engel Class I based on location of resection (temporal compared with extratemporal).

  • View in gallery

    Kaplan–Meier graph showing the proportion of patients in each pathological category who underwent temporal lobe resections with Engel Class I outcome. The inset table presents the number of patients at risk in the three different categories at 1, 2, 5, and 10 years postoperatively.

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    Kaplan–Meier graph showing the proportion of all patients in Engel Class I based on pathological category.

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    Kaplan–Meier graph showing the proportion of patients in Engel Class I based on age at surgery.

  • View in gallery

    Kaplan–Meier graph showing the quadratic relationship between age and outcome of surgery. The younger and older patients had less satisfactory outcomes.

  • View in gallery

    Kaplan–Meier graph showing the proportion of patients in Engel Class I based on preoperative duration of seizures.



Abou-Khalil BAndermann EAndermann FOlivier AQuesney LF: Temporal lobe epilepsy after prolonged febrile convulsions: excellent outcome after surgical treatment. Epilepsia 34:8788831993


Adelson PDO’Rourke DKAlbright AL: Chronic invasive monitoring for identifying seizure foci in children. Neurosurg Clin N Am 6:4915041995


Al-Kaylani MAbou-Khalil B: Seizure freedom off antiepileptic drugs after temporal lobe surgery. Epilepsia 43 :Suppl 73162002


Andermann EMultifactorial inheritance of generalized and focal epilepsy. Anderson VHauser WPenry J: Genetic Basis of the Epilepsies New YorkRaven Press1982. 355374


Armon CRadtke RAFriedman AHDawson DV: Predictors of outcome of epilepsy surgery: multivariate analysis with validation. Epilepsia 37:8148211996


Awad IANayel MHLuders H: Second operation after the failure of previous resection for epilepsy. Neurosurgery 28:5105181991


Behrens ESchramm JZentner JKonig R: Surgical and neurological complications in a series of 708 epilepsy surgery procedures. Neurosurgery 41:1101997


Berkovic SFMcIntosh AMKalnins RMJackson GDFabinyi GCBrazenor GA: Preoperative MRI predicts outcome of temporal lobectomy: an actuarial analysis. Neurology 45:135813631995


Cascino GD: Clinical correlations with hippocampal atrophy. Magn Reson Imaging 13:113311361995


Cascino GDKelly PJHirschorn KAMarsh WRSharbrough FW: Stereotactic resection of intra-axial cerebral lesions in partial epilepsy. Mayo Clin Proc 65:105310601990


Cascino GDTrenerry MRJack CR JrDodick DSharbrough FWSo EL: Electrocorticography and temporal lobe epilepsy: relationship to quantitative MRI and operative outcome. Epilepsia 36:6926961995


Cascino GDTrenerry MRSharbrough FWSo ELMarsh WRStrelow DC: Depth electrode studies in temporal lobe epilepsy: relation to quantitative magnetic resonance imaging and operative outcome. Epilepsia 36:2302351995


Cascino GDTrenerry MRSo ELSharbrough FWShin CLagerlund TD: Routine EEG and temporal lobe epilepsy: relation to long-term EEG monitoring, quantitative MRI, and operative outcome. Epilepsia 37:6516561996


Cendes FCook MJWatson CAndermann FFish DRShorvon SD: Frequency and characteristics of dual pathology in patients with lesional epilepsy. Neurology 45:205820641995


Cukiert ABuratini JAMachado ESousa AVieira JOArgentoni M: Results of surgery in patients with refractory extratemporal epilepsy with normal or nonlocalizing magnetic resonance findings investigated with subdural grids. Epilepsia 42:8898942001


Eliashiv SDDewar SWainwright IEngel J JrFried I: Long-term follow-up after temporal lobe resection for lesions associated with chronic seizures. Neurology 48:6216261997


Elwes RDDunn GBinnie CDPolkey CE: Outcome following resective surgery for temporal lobe epilepsy: a prospective follow up study of 102 consecutive cases. J Neurol Neurosurg Psychiatry 54:9499521991


Engel J JrOutcome with respect to epileptic seizures. Engel J Jr: Surgical Treatment of the Epilepsies New YorkRaven Press1987. 553570


Engel J JrVan Ness PRasmussen TOutcome with respect to epileptic seizures. Engel J Jr: Surgical Treatment of the Epilepsies ed. 2 New YorkRaven Press1993. 609621


Falconer MSerafetinides E: A follow-up study of surgery in temporal lobe epilepsy. J Neurol Neurosurg Psychiatry 26:1541651963


Ficker DMSo ELMosewich RKRadhakrishnan KCascino GDSharbrough FW: Improvement and deterioration of seizure control during the postsurgical course of epilepsy surgery patients. Epilepsia 40:62671999


Fish DRSmith SJQuesney LFAndermann FRasmussen T: Surgical treatment of children with medically intractable frontal or temporal lobe epilepsy: results and highlights of 40 years’ experience. Epilepsia 34:2442471993


Foldvary NNashold BMascha EThompson EALee NMc-Namara JO: Seizure outcome after temporal lobectomy for temporal lobe epilepsy: a Kaplan–Meier survival analysis. Neurology 54:6306342000


Garcia PALaxer KDBarbaro NMDillon WP: Prognostic value of qualitative magnetic resonance imaging hippocampal abnormalities in patients undergoing temporal lobectomy for medically refractory seizures. Epilepsia 35:5205241994


Germano IMPoulin NOlivier A: Reoperation for recurrent temporal lobe epilepsy. J Neurosurg 81:31361994


Goldstein RHarvey ASDuchowny MJayakar PAltman NResnick T: Preoperative clinical, EEG, and imaging findings do not predict seizure outcome following temporal lobectomy in childhood. J Child Neurol 11:4454501996


Guldvog BLoyning YHauglie-Hanssen EFlood SBjornaes H: Predictive factors for success in surgical treatment for partial epilepsy: a multivariate analysis. Epilepsia 35:5665781994


Guldvog BLoyning YHauglie-Hanssen EFlood SBjornaes H: Surgical treatment for partial epilepsy among Norwegian adults. Epilepsia 35:5405531994


Guldvog BLoyning YHauglie-Hanssen EFlood SBjornaes H: Surgical treatment for partial epilepsy among Norwegian children and adolescents. Epilepsia 35:5545651994


Guldvog BLoyning YHauglie-Hanssen EFlood SBjornaes H: Surgical versus medical treatment for epilepsy. I. Outcome related tosurvival, seizures, and neurologic deficit. . Epilepsia 32:3753881991


Guldvog BLoyning YHauglie-Hanssen EFlood SBjornaes H: Surgical versus medical treatment for epilepsy. II. Outcome relatedto social areas.. Epilepsia 32:4774861991


Hennessy MJElwes RDBinnie CDPolkey CE: Failed surgery for epilepsy. A study of persistence and recurrence ofseizures following temporal resection.. Brain 123:244524662000


Hennessy MJElwes RDHonavar MRabe-Hesketh SBinnie CDPolkey CE: Predictors of outcome and pathological considerations in the surgical treatment of intractable epilepsy associated with temporal lobe lesions. J Neurol Neurosurg Psychiatry 70:4504582001


Hong KSLee SKKim JYLee DSChung CK: Pre-surgical evaluation and surgical outcome of 41 patients with non-lesional neocortical epilepsy. Seizure 11:1841922002


Jack CR JrSharbrough FWCascino GDHirschorn KAO’Brien PCMarsh WR: Magnetic resonance image-based hippocampal volumetry: correlation with outcome after temporal lobectomy. Ann Neurol 31:1381461992


Jack CR JrSharbrough FWMarsh WR: Use of MR imaging for quantitative evaluation of resection for temporal lobe epilepsy. Radiology 169:4634681988


Janszky JJanszky ISchulz RHoppe MBehne FPannek HW: Temporal lobe epilepsy with hippocampal sclerosis: predictors for long-term surgical outcome. Brain 128:3954042005


Jennum PDhuna ADavies KFiol MMaxwell R: Outcome of resective surgery for intractable partial epilepsy guided by subdural electrode arrays. Acta Neurol Scand 87:4344371993


Jensen I: Temporal lobe epilepsy. Etiological factors and surgical results.. Acta Neurol Scand 53:1031181976


Jeong SWLee SKKim KKKim HKim JYChung CK: Prognostic factors in anterior temporal lobe resections for mesial temporal lobe epilepsy: multivariate analysis. Epilepsia 40:173517391999


Johnston SCHorn JKValente JSimon RP: The role of hypoventilation in a sheep model of epileptic sudden death. Ann Neurol 37:5315371995


Jutila LImmonen AMervaala EPartanen JPartanen KPuranen M: Long term outcome of temporal lobe epilepsy surgery: analyses of 140 consecutive patients. J Neurol Neurosurg Psychiatry 73:4864942002


Kellett MWSmith DFBaker GAChadwick DW: Quality of life after epilepsy surgery. J Neurol Neurosurg Psychiatry 63:52581997


Kilpatrick CCook MMatkovic ZO’Brien TKaye AMurphy M: Seizure frequency and duration of epilepsy are not risk factors for postoperative seizure outcome in patients with hippocampal sclerosis. Epilepsia 40:8999031999


Kim YDHeo KPark SCHuh KChang JWChoi JU: Antiepileptic drug withdrawal after successful surgery for intractable temporal lobe epilepsy. Epilepsia 46:2512572005


Kumlien EDoss RCGates JR: Treatment outcome in patients with mesial temporal sclerosis. Seizure 11:4134172002


Kuzniecky RBurgard SFaught EMorawetz RBartolucci A: Predictive value of magnetic resonance imaging in temporal lobe epilepsy surgery. Arch Neurol 50:65691993


Lee SASpencer DDSpencer SS: Intracranial EEG seizure-onset patterns in neocortical epilepsy. Epilepsia 41:2973072000


Lieb JPEngel J JrBabb TL: Interhemispheric propagation time of human hippocampal seizures. I.Relationship to surgical outcome.. Epilepsia 27:2862931986


Luders HMurphy DAwad IWyllie EDinner DSMorris HH III: Quantitative analysis of seizure frequency 1 week and 6, 12, and 24 months after surgery of epilepsy. Epilepsia 35:117411781994


Ludwig BIMarsan CAvan Buren J: Depth and direct cortical recording in seizure disorders of extratemporal origin. Neurology 26:108510991976


Mathern GWBabb TLVickrey BGMelendez MPretorius JK: The clinical-pathogenic mechanisms of hippocampal neuron loss and surgical outcomes in temporal lobe epilepsy. Brain 118:1051181995


McIntosh AMKalnins RMMitchell LAFabinyi GCBriellmann RSBerkovic SF: Temporal lobectomy: long-term seizure outcome, late recurrence and risks for seizure recurrence. Brain 127:201820302004


McIntosh AMWilson SJBerkovic SF: Seizure outcome after temporal lobectomy: current research practice and findings. Epilepsia 42:128813072001


Morris HHMatkovic ZEstes MLPrayson RAComair YGTurnbull J: Ganglioglioma and intractable epilepsy: clinical and neurophysiologic features and predictors of outcome after surgery. Epilepsia 39:3073131998


Mosewich RKSo ELO’Brien TJCascino GDSharbrough FWMarsh WR: Factors predictive of the outcome of frontal lobe epilepsy surgery. Epilepsia 41:8438492000


O’Brien TJO’Connor MKMullan BPBrinkmann BHHanson DJack CR: Subtraction ictal SPECT co-registered to MRI in partial epilepsy: description and technical validation of the method with phantom and patient studies. Nucl Med Commun 19:31451998


O’Brien TJSo ELMullan BPCascino GDHauser MFBrinkmann BH: Subtraction peri-ictal SPECT is predictive of extratemporal epilepsy surgery outcome. Neurology 55:166816772000


O’Brien TJSo ELMullan BPHauser MFBrinkmann BHBohnen NI: Subtraction ictal SPECT co-registered to MRI improves clinical usefulness of SPECT in localizing the surgical seizure focus. Neurology 50:4454541998


O’Brien TJSo ELMullan BPHauser MFBrinkmann BHJack CR Jr: Subtraction SPECT co-registered to MRI improves postictal SPECT localization of seizure foci. Neurology 52:1371461999


Ojemann GBourgeosis BEarly postoperative management. Engel J Jr: Surgical Treatment of the Epilepsies New YorkRaven Press1993. 539540


Paglioli EPalmini APaglioli Eda Costa JCPortuguez MMartinez JV: Survival analysis of the surgical outcome of temporal lobe epilepsy due to hippocampal sclerosis. Epilepsia 45:138313912004


Paillas JEGastaut HSedan RBureau M: Long-term results of conventional surgical treatment for epilepsy.Delayed recurrence after a period of 10 years.. Surg Neurol 20:1891931983


Prevedello DMSandmann MCEbner A: Prognostic factors in mesial temporal lobe epilepsy surgery. Arq Neuropsiquiatr 58:2072132000


Primrose DOjemann GOutcome of resective surgery for temporal lobe epilepsy. Luders H: Epilepsy Surgery New YorkRaven Press1992. 601611


Radhakrishnan KSo ELSilbert PLJack CR JrCascino GDSharbrough FW: Predictors of outcome of anterior temporal lobectomy for intractable epilepsy: a multivariate study. Neurology 51:4654711998


Rasmussen T: Tailoring of cortical excisions for frontal lobe epilepsy. Can J Neurol Sci 18 :4 Suppl6066101991


Rasmussen TB: Surgical treatment of complex partial seizures: results, lessons, and problems. Epilepsia 24 :Suppl 1S65S761983


Raymond AAFish DRStevens JMCook MJSisodiya SMShorvon SD: Association of hippocampal sclerosis with cortical dysgenesis in patients with epilepsy. Neurology 44:184118451994


Reynolds EHElwes RDShorvon SD: Why does epilepsy become intractable? Prevention of chronic epilepsy.. Lancet 2:9529541983


Rougier ADartigues JFCommenges DClaverie BLoiseau PCohadon F: A longitudinal assessment of seizure outcome and overall benefit from 100 cortectomies for epilepsy. J Neurol Neurosurg Psychiatry 55:7627671992


Salanova VAndermann FRasmussen TOlivier AQuesney L: The running down phenomenon in temporal lobe epilepsy. Brain 119:9899961996


Salanova VMarkand OWorth R: Longitudinal follow-up in 145 patients with medically refractory temporal lobe epilepsy treated surgically between 1984 and 1995. Epilepsia 40:141714231999


Salanova VMarkand OWorth R: Temporal lobe epilepsy surgery: outcome, complications, and late mortality rate in 215 patients. Epilepsia 43:1701742002


Salanova VMarkand OWorth RSmith RWellman HHutchins G: FDG-PET and MRI in temporal lobe epilepsy: relationship to febrile seizures, hippocampal sclerosis and outcome. Acta Neurol Scand 97:1461531998


Salanova VMarkand ONWorth R: Clinical characteristics and predictive factors in 98 patients with complex partial seizures treated with temporal resection. Arch Neurol 51:100810131994


Salanova VQuesney LFRasmussen TAndermann FOlivier A: Reevaluation of surgical failures and the role of reoperation in 39 patients with frontal lobe epilepsy. Epilepsia 35:70801994


Salanova VRasmussen TAndermann F: The running down phenomenon in temporal lobe epilepsy. Adv Neurol 81:1651691999


Schiller YCascino GDSo ELMarsh WR: Discontinuation of antiepileptic drugs after successful epilepsy surgery. Neurology 54:3463492000


Schmidt DBaumgartner CLoscher W: Seizure recurrence after planned discontinuation of antiepileptic drugs in seizure-free patients after epilepsy surgery: a review of current clinical experience. Epilepsia 45:1791862004


Sirven JIMalamut BLO’Connor MJSperling MR: Temporal lobectomy outcome in older versus younger adults. Neurology 54:216621702000


Smith JRLee MRKing DWMurro AMPark YDLee GP: Results of lesional vs. nonlesional frontal lobe epilepsy surgery.. Stereotact Funct Neurosurg 69:2022091997


So ELRadhakrishnan KSilbert PLCascino GDSharbrough FWO’Brien PC: Assessing changes over time in temporal lobectomy: outcome by scoring seizure frequency. Epilepsy Res 27:1191251997


So NOlivier AAndermann FGloor PQuesney LF: Results of surgical treatment in patients with bitemporal epileptiform abnormalities. Ann Neurol 25:4324391989


Spencer DDSpencer SSMattson RHWilliamson PDNovelly RA: Access to the posterior medial temporal lobe structures in the surgical treatment of temporal lobe epilepsy. Neurosurgery 15:6676711984


Spencer SS: Long-term outcome after epilepsy surgery. Epilepsia 37:8078131996


Spencer SSBerg ASpencer DD: Predictors of remission of one year after resective epilepsy surgery. Epilepsia 34 :Suppl 6271993


Spencer SSSpencer DDWilliamson PDMattson R: Combined depth and subdural electrode investigation in uncontrolled epilepsy. Neurology 40:74791990


Sperling MRFeldman HKinman JLiporace JDO’Connor MJ: Seizure control and mortality in epilepsy. Ann Neurol 46:45501999


Sperling MRO’Connor MJSaykin AJPlummer C: Temporal lobectomy for refractory epilepsy. JAMA 276:4704751996


Tellez-Zenteno JDhar RWiebe S: Long-term seizure outcomes following epilepsy surgery: a systematic review and meta-analysis. Brain 128:118811982005


Trenerry MR: Neuropsychologic assessment in surgical treatment of epilepsy. Mayo Clin Proc 71:119612001996


Van Buren JMAjmone-Marsan CMutsuga NSadowsky D: Surgery of temporal lobe epilepsy. Adv Neurol 8:1551961975


Vickrey B: Mortality in consecutive of 248 adolescents and adults who underwent diagnostic evaluation for epilepsy surgery. Epilepsia 38 :Suppl 11S67S691997


Walczak TSRadtke RAMcNamara JOLewis DVLuther JSThompson E: Anterior temporal lobectomy for complex partial seizures: evaluation, results, and long-term follow-up in 100 cases. Neurology 40:4134181990


Wass CTRajala MMHughes JMSharbrough FWOfford KPRademacher DM: Long-term follow-up of patients treated surgically for medically intractable epilepsy: results in 291 patients treated at Mayo Clinic Rochester between July 1972 and March 1985. Mayo Clin Proc 71:110511131996


Watson CJack CR JrCendes F: Volumetric magnetic resonance imaging. Clinical applications and contributions to the understanding of temporal lobe epilepsy. Arch Neurol 54:152115311997


Wiebe SBlume WTGirvin JPEliasziw M: A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med 345:3113182001


Wieser HGOrtega MFriedman AYonekawa Y: Long-term seizure outcomes following amygdalohippocampectomy. J Neurosurg 98:7517632003


Williamson PDFrench JAThadani VMKim JHNovelly RASpencer SS: Characteristics of medial temporal lobe epilepsy: II. Interictal and ictal scalp electroencephalography, neuropsychological testing, neuroimaging, surgical results, and pathology. Ann Neurol 34:7817871993


Wilson SJSaling MMKincade PBladin PF: Patient expectations of temporal lobe surgery. Epilepsia 39:1671741998


Wingkun ECAwad IALuders HAwad CA: Natural history of recurrent seizures after resective surgery for epilepsy. Epilepsia 32:8518561991


Wyler ARHermann BPRichey ET: Results of reoperation for failed epilepsy surgery. J Neurosurg 71:8158191989


Wyler ARHermann BPSomes G: Extent of medial temporal resection on outcome from anterior temporal lobectomy: a randomized prospective study. Neurosurgery 37:9829911995


Wyllie ELuders HMorris HH IIILesser RPDinner DSHahn J: Clinical outcome after complete or partial cortical resection for intractable epilepsy. Neurology 37:163416411987


Yoon HHKwon HLMattson RHSpencer DDSpencer SS: Long-term seizure outcome in patients initially seizure-free after resective epilepsy surgery. Neurology 61:4454502003


Zentner JHufnagel AOstertun BWolf HKBehrens ECampos MG: Surgical treatment of extratemporal epilepsy: clinical, radiologic, and histopathologic findings in 60 patients. Epilepsia 37:107210801996




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