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PubMed This is a summary of 17 peer-reviewed journal articles Updated
Epileptology

When Medications Aren't Enough: Surgical Evaluation

At a Glance

When two appropriate antiseizure medicines fail to achieve sustained seizure freedom in MTLE-HS, the epilepsy is generally considered drug-resistant. A specialized evaluation can compare surgery, laser ablation, and neuromodulation without committing the patient to treatment.

If you have tried multiple medications and are still having seizures, you may feel frustrated or lose hope. However, this is often the point where the most effective treatments for Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS) actually begin. Understanding when to shift from “trying another pill” to a “specialized evaluation” is a critical turning point in your care.

Defining ‘Drug-Resistant’ Epilepsy

The International League Against Epilepsy (ILAE) provides a clear definition for when a patient should seek a higher level of care. You are considered to have drug-resistant epilepsy if you have failed two appropriate trials of antiseizure medications to achieve sustained seizure freedom [1][2].

For a trial to be “appropriate,” the medication must have been:

  1. Correctly Chosen: It was the right drug for your specific seizure type (focal seizures) [3][4].
  2. Adequately Dosed: You reached an effective dose level and stayed on it long enough to see if it worked [2][4].
  3. Tolerated: You didn’t have to stop it early due to side effects [1]. (While an intolerable drug is not technically a failure of efficacy, experiencing two such medication problems still warrants a specialist discussion).

The ‘Rule of Two’

It is a common pitfall to keep trying a third, fourth, or fifth medication in the hopes that the next one will finally work. Statistics show that if the first two well-chosen medications fail to control your seizures, the chance that a third or fourth medication will lead to total seizure freedom is generally very low [3][5].

In contrast, for people with MTLE-HS, surgical options often provide a much higher chance of becoming seizure-free—sometimes ranging from 60% to 80% for carefully selected candidates—compared to much lower odds with continued medication alone [6][7]. Waiting too long for an evaluation can lead to years of unnecessary seizures, which may impact your long-term memory, risk of injury, and quality of life [8][9].

What is a Comprehensive Epilepsy Center?

When medications aren’t enough, guidelines recommend a prompt referral to a Comprehensive Epilepsy Center (often called a Level 4 center in the US) [5][10]. These centers offer a level of expertise and technology not found in standard neurology offices:

  • The Multidisciplinary Team: You aren’t just seeing one doctor. Your case is reviewed by a team including epileptologists (neurologists who specialize only in epilepsy), neurosurgeons, specialized neuroradiologists, and neuropsychologists [10][11].
  • The Surgical Conference: The entire team meets to discuss your test results together, ensuring that everyone agrees on the best path forward [12].
  • Advanced Testing: They have access to specialized tools like long-term Video-EEG in an Epilepsy Monitoring Unit (EMU), PET scans, and sometimes Stereo-EEG (SEEG), where tiny electrodes map your seizure network if noninvasive tests are discordant [13][14].

Evaluation is Not a Commitment

It is important to remember that a presurgical evaluation is simply an information-gathering mission [15].

  • No Pressure: Going through the tests does not mean you have to have surgery. The goal is to provide you with a “map” of your epilepsy.
  • Multiple Options: The evaluation might reveal that you are a candidate for traditional surgery, but it could also point toward newer, less-invasive options like Laser Ablation (LITT) or “pacemaker-like” devices called Neuromodulation (such as RNS or VNS) [16][17].
  • Personal Choice: Once the evaluation is complete, the team will present you with the risks and benefits of each option. You remain the person in charge of your treatment plan.

Common questions in this guide

When is MTLE-HS epilepsy considered drug-resistant?
Epilepsy is generally considered drug-resistant when two appropriate antiseizure medication trials fail to produce sustained seizure freedom. Each trial should use a medicine suited to focal seizures at an effective dose for enough time, while being tolerated; repeated medication side effects also warrant specialist discussion.
What should I do if two appropriate medications have not stopped my seizures?
Ask about prompt referral to a comprehensive epilepsy center, often called a Level 4 center in the United States. Its team can review your diagnosis, medication history, and test results and determine whether further medication, surgery, laser ablation, or neuromodulation may fit your situation.
What tests are used in a presurgical epilepsy evaluation?
A comprehensive center may use long-term video-EEG in an Epilepsy Monitoring Unit, PET scans, and sometimes Stereo-EEG when noninvasive test results do not agree. Specialists review the findings together to map the seizure network and compare treatment options.
Does an epilepsy surgery evaluation mean I have to have an operation?
No. A presurgical evaluation is an information-gathering process and does not obligate you to undergo surgery. The results may point to traditional surgery, laser ablation, neuromodulation, or continued nonsurgical management, and you remain involved in the decision.
How effective can surgery be for MTLE-HS?
For carefully selected people with MTLE-HS, surgical treatment may lead to seizure freedom in roughly 60% to 80% of cases. Your epilepsy team can provide a more personal estimate after reviewing your test results and overall situation.
Which specialists are involved in a Level 4 epilepsy center?
The team may include epileptologists, neurosurgeons, neuroradiologists, and neuropsychologists. They review your case together in a surgical conference so that recommendations reflect the full set of test results and treatment choices.

Questions For You

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Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Do I meet the formal definition of 'drug-resistant epilepsy' based on the medications I have already tried?
  2. 2.How many of my prior medications reached an 'adequate dose' and were considered correct for my specific seizure type?
  3. 3.What is my personal chance of becoming seizure-free with a third medication versus a surgical evaluation?
  4. 4.What specific tests—such as PET scans or long-term EEG—would a Level 4 center perform that are not available here?
  5. 5.If I go for an evaluation at a specialized center, will I be assigned a team that includes a neurosurgeon, a neuropsychologist, and an epileptologist?

References

References (17)
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    Giussani G, Canelli V, Bianchi E, et al.

    Epilepsy & behavior : E&B 2016; (55()):30-7.

    PMID: 26731716
  2. 2

    Exploring metabolic biomarkers and pathways in pharmacoresistant epilepsy: A systematic review.

    Lim ZD, Abdullah NAS, Lim KS, et al.

    Epilepsy research 2025; (218()):107656 doi:10.1016/j.eplepsyres.2025.107656.

    PMID: 40945053
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    Clinical Management of Drug Resistant Epilepsy: A Review on Current Strategies.

    Guery D, Rheims S

    Neuropsychiatric disease and treatment 2021; (17()):2229-2242 doi:10.2147/NDT.S256699.

    PMID: 34285484
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    Response to subsequent antiseizure medications after first antiseizure medication failure in newly diagnosed epilepsy.

    Hersi H, Saarinen JT, Raitanen J, Peltola J

    Frontiers in neurology 2022; (13()):1042168 doi:10.3389/fneur.2022.1042168.

    PMID: 36438960
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    The Medical journal of Australia 2018; (208(5)):226-233 doi:10.5694/mja17.00951.

    PMID: 29540143
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    Resective epilepsy surgery for drug-resistant focal epilepsy: a review.

    Jobst BC, Cascino GD

    JAMA 2015; (313(3)):285-93 doi:10.1001/jama.2014.17426.

    PMID: 25602999
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    Which parameters influence cognitive, psychiatric and long-term seizure outcome in mesial temporal lobe epilepsy after selective amygdalohippocampectomy?

    Jud J, Stefanits H, Gelpi E, et al.

    Journal of neurology 2024; (271(7)):4249-4257 doi:10.1007/s00415-024-12343-y.

    PMID: 38619597
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    Temporal Trends in Hippocampal Sclerosis Surgery: An Observational Study From a Tertiary Epilepsy Centre.

    Vassallo P, Gursal V, Xiong W, et al.

    European journal of neurology 2025; (32(1)):e70041 doi:10.1111/ene.70041.

    PMID: 39804171
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    Predictors of meaningful improvement in quality of life after temporal lobe epilepsy surgery: A prospective study.

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    Epilepsia 2017; (58(5)):755-763 doi:10.1111/epi.13721.

    PMID: 28332703
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    Guidelines for Specialized Epilepsy Centers: Executive Summary of the Report of the National Association of Epilepsy Centers Guideline Panel.

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    Neurology 2024; (102(4)):e208087 doi:10.1212/WNL.0000000000208087.

    PMID: 38306606
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    What can we do for people with drug-resistant epilepsy? The 2016 Wartenberg Lecture.

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    Neurology 2016; (87(23)):2483-2489 doi:10.1212/WNL.0000000000003407.

    PMID: 27920283
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    MRI-negative PET-negative epilepsy long-term surgical outcomes: A single-institution retrospective review.

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    Epilepsy research 2020; (167()):106481 doi:10.1016/j.eplepsyres.2020.106481.

    PMID: 33039796
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    Epilepsy monitoring unit practices and safety among NAEC epilepsy centers: A census survey.

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    PMID: 38070408
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    Is intracranial electroencephalography mandatory for MRI-negative neocortical epilepsy surgery?

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    PMID: 36242573
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    Stereotactic EEG-guided radiofrequency thermocoagulation versus anterior temporal lobectomy for mesial temporal lobe epilepsy with hippocampal sclerosis: study protocol for a randomised controlled trial.

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    Current practices and trends in surgical decision-making for children with Lennox-Gastaut syndrome: A cross-sectional survey by the Pediatric Epilepsy Research Consortium.

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    PMID: 40965114

This page is for informational purposes only and does not constitute medical advice. An epileptologist or comprehensive epilepsy team can interpret your medication history and discuss the risks and benefits of evaluation and treatment options.