Reasons To Have Epilepsy Surgery - Prof. Sarat Chandra, All India Institute of Medical Sciences
Lots of people are very scared of epilepsy surgery. What are the risks of having it? What are the risks of not having it? Potential benefits? The processes beforehand? Hear all about it from epilepsy surgeon Prof. Sarat Chandra. Watch/listen/read here 👇!
Episode Highlights
Various epilepsy surgeries include: resective, disconnective, ablation, and neuromodulation
Investigative procedures can include EEG, MRI, PET, MEG, ictal SPECT
Recurrent seizures can cause brain damage, injury, status epilepticus, and death in some
About Sarat Chandra
Sarat is a neurosurgeon who over the past three decades, he has established and led one of the largest epilepsy surgery programs in the world, with experience of more than 4,000 epilepsy surgeries encompassing the full spectrum of paediatric and adult epilepsy procedures, including hemispherotomy, hemispheric disconnection, corpus callosotomy, SEEG, robotic epilepsy surgery, neuromodulation, vagus nerve stimulation, and deep brain stimulation. He founded India’s first comprehensive Centre of Excellence for Epilepsy integrating advanced neuroimaging, MEG, neurobiology, genetics, artificial intelligence, and translational epilepsy research.
Full profile: Sarat-Chandra
Topics mentioned
neurosurgery
drug resistant epilepsy
mortality
sudep
status epilepticus
epileptic encephalopathy
resection
disconnection
neuromodulation
focal cortical dysplasia
robotic-guided radiofrequency ablation
stereoelectroencephalography
ictal spect
pet
meg
functional dissociative seizures
cognition
grey matter
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Trailer
00:00 Sarat Chandra
You know, there are so many options for epilepsy surgery available. But fundamentally we can divide it into 3 parts. One is a resective surgery where we take out certain tissues of the brain and these tissues of the brain are already damaged, you know, they are abnormal electrophysiologically. So, in terms of imaging, you may still not find a significant abnormality in that, but electrophysiologically and maybe histopathologically they are abnormal
Intro
00:28 Torie Robinson
So last week, neurologist Dr. Manjari Tripathi chatted with us all about when epilepsy surgery should be considered - and how individualised care (“care” being a crucial word here!) for people with an epilepsy should be. Today, we have neurosurgeon Dr. Sarat Chandra who’s going to take us inside the operating theatre (well, not literally, no surgery imagery here!), but he’s going to explain the different types of epilepsy surgery there are, and, the potential outcomes of epilepsy surgery today in 2026!
00:57 Torie Robinson
Thank you so much for joining us, Sarat. Could you please just tell us a bit about yourself and what you do?
Meet Prof. Sarat Chandra
01:02 Sarat Chandra
Well, I'm the professor and the chairman of Department of Neurosurgery at the All India Institute of Medical Sciences, New Delhi, which happens to be the most premier university hospital in India.
01:15 Torie Robinson
And so, you specifically are an epilepsy surgeon, is that correct?
01:16 Sarat Chandra
That's right.
01:19 Torie Robinson
Okay. So, lots of people, even some clinicians, we have to say, find just the idea of epilepsy surgery a bit scary! And I guess the word would be like “daunting”, just the thought of it. So, what happens these days during modern epilepsy surgery? And how do you get over that challenge, as well, with the clinicians?
01:42 Sarat Chandra
That's an excellent question, Torie. At the outset, would like to acknowledge you for taking this initiative because I'm sure this would reach out to those thousands of people with epilepsy or who may be potentially requiring epilepsy surgery.
Reasons to get epilepsy surgery
01:55 Sarat Chandra
You're right, when you mention the word “surgery”, it does strike an element of fear. And most often, the patients think that, you know, having epilepsy is not like having a brain tumour or it's not something fatal…
02:06 Torie Robinson
Right!
01:42 Sarat Chandra
…it's “only” seizures. So why should I actually get surgery done? But there are 2 most important components/reasons why we should think of surgery in drug-resistant epilepsy. So, mind you, the surgery is only required in cases where you cannot control the epilepsy with drugs, and as Manjari has said by the definition of drug-resistant epilepsy by the International League is that if it's 2 or more drugs which do not control your seizures. A couple of reasons why epilepsy surgery is a compelling strategy to be done in patients with… persons with drug-resistant epilepsy is firstly, epilepsy itself is associated with mortality. Now the mortality itself may be very less, but it's cumulative, which means it's about 0.5%, which keeps on adding every year, which translates into the fact that if a person is having seizures or epilepsy for the past 10 years, the mortality or the chance of him or her dying because of epilepsy is about 5%.
03:07 Torie Robinson
And that could be SUDEP, right? That could be SUDEP, it could be injury.
03:12 Sarat Chandra
It could be SUDEP, it could be injury, it could be status, it could be a number of reasons. But there are enough statistical studies to show that the mortality is not trivial and it's cumulative, keeps on adding every year. The second reason is that epilepsy is disabling. So, we have to imagine that it's a short circuit which is passing through the brain and every time you have a seizure, it's like a couple of million neurons which are getting destroyed forever. And because of the fact that there are billions of neurons within the brain, you may not feel the effect immediately. But if it continues over a period of time, it could be disastrous, especially for the growing brain in kids. So when they have a growing brain - and this phenomenon is called Epileptic Encephalopathy - which means, fundamentally, you know patients have seizures for 10-15 years they're going to lose a significant chunk of their cognitive abilities. And the way we explain this to the parents, especially for young children, is that “Look, here today you are able to identify your kid because your kid is able to call out to you or tell your name and that's the reason why you strike this identity with your kid or this connection with your kid. But this may not be possible if you don't get him treated… get him or her treated for the next decade or so because your kid may not be able to even recognise you because of epileptic encephalopathy.”. So these are the 2 most compelling reasons why we should seriously think of surgery. Firstly, there is a risk of mortality which is cumulative. Secondly, the effects of epilepsy going on in the brain could be disastrous over a period of time.
04:48 Torie Robinson
As someone who's had surgery, and wasted 20 years, I could not agree more. So, tell us what types of surgery there are, because even for instance, from when I had surgery 13 years ago, to the present, we've, you know, we've come so far. What are our options today?
Different types of epilepsy surgery
05:03 Sarat Chandra
Continuing partly with your first question, that… if… because the answer is also partly in this question, that when we say that surgery is kind of frightening, we need to understand that epilepsy surgery is an umbrella term. So, it's not as if you have a single surgery, you have so many modalities of surgeries and each of the surgical strategy has different outcome, different risks and different kind of complexity available for it. So, when we say “epilepsy surgery” it’s not the same thing for everybody. You could have surgeries which could have excellent outcomes to the tune of 80 to 90%. At the same time, you could have surgeries which may not cure seizures, but they're very significant to reduce the seizures. So, we call them as “seizure reducing surgeries”. There are people who call them as “palliative surgeries”, but I personally don't prefer the word palliative because palliative gives a conversion that it is something incurable. It's a word which is more commonly attached to cancers or to malignant illness which do not have a cure. So, we are much better off saying that these are seizure-reducing surgeries. They may not cure your seizures, but you have significant reduction to the tune of 80-90% which will have a significant impact on your quality of life.
06:21 Torie Robinson
And also, I think worth mentioning is that you say 80 to 90%, but it can differ for each person, can't it? So, it might be 80 to 90% in one person. For instance, in myself, it was 60% (the estimate). So, it can vary a great deal.
06:35 Sarat Chandra
You're right, absolutely. You know, there are so many options for epilepsy surgery available. But fundamentally we can divide it into 3 parts:
One is a resective surgery where we take out certain tissues of the brain and these tissues of the brain are already damaged, you know, they are abnormal electrophysiologically. So, in terms of imaging, you may still not find a significant abnormality in that, but electrophysiologically and maybe histopathologically they are abnormal. So, you need to take it out;
And then you have disconnected surgeries where you disconnect that area from rest of the brain and;
Then you have neuromodulation.
So, these are the 3 primary areas where you can classify your epilepsy surgery and each of them have again different types of subcategories and each of them have again have different kinds of outcomes. Rightly, as you pointed out, outcomes depend upon the age of the patient, the duration of seizures, the complexity of the networks, the kind of localisation we can do before surgery, the kind of pathological substrate which could be identified, and so on. You know, there are so many factors and that's the reason it's important to individualise each patient before we think of a surgical strategy. And that's the reason, you know, there's a whole team which works. There is a neurologist, there is a nuclear medicine, there is a radiologist, there is a clinical psychologist who sit with the surgeon. And that's very much the reason it's a very much a team effort where you sit together and then we decide that this is what we are going to do for this patient and this is what is the expected outcome and this is what we are going to speak to the patient or to the caregiver.
Fear, full investigations, and consent for epilepsy surgery
08:19 Torie Robinson
And also, I think what's important to say, you speak with them, don't you? Because it's like a decision made with the patient and the caregiver. It's not just something that is decided by yourself or decided by the multidisciplinary team.
08:32 Sarat Chandra
Absolutely, the consent, I think, in epilepsy surgery is totally different. And what we do in our centre is we have at least 3 rounds of discussion with our own team before we decide what we need to do. One is before admission, one is at the time of admission, and one is at the time of surgery. And then finally we call the patients caregivers where we have a detailed discussion with them for at least 1 hour or so. And we explain them all the alternatives that we have thought of, all the possibilities that could exist for the surgical strategy, and what is the final decision we have taken and why we have taken this decision, and why we think that this decision is good for that patient, and what are the expected outcomes for this surgical strategy. So you're right, it's kind of a totally customised for each and every patient.
09:22 Torie Robinson
Loads of people are really scared of surgery. I think one of the reasons is because “It's your brain!”, right? And then another one is they think it's just a relationship between them and the surgeon. A lot of the time people don't realise that there are so many people involved in assessing risk, assessing potential benefits, who are looking at the psychiatric aspects, looking at neurophysiology, looking at everything. How do you… what's your experience with people's nervousness, fear, how many people or what percentage go “I'm not doing it because I'm too scared.” versus people who say “Go for it.”?
09:58 Sarat Chandra
That's an excellent question and that's the reason why the consenting is done in various steps. We never say surgery right from the word go. We do the full investigations and that's where we have to convince the patient slowly over a period of time and allow their fears. So, it's not a single step process. It's a multi-step process over a period of time. You know, they become convinced, but there could be also different surgical strategies. For instance, you know, I can tell a case of a vice president from a multinational company who had a focal cortical dysplasia very close to the motor strip. When we did a functional imaging we found that even though it's closed it was away from the motor strip but he was very concerned of undergoing surgery at the first step because he thought that if he has any deficit he could potentially lose his job or his capabilities (and he was a highly functioning individual). And that's the reason over there we did a robotic-guided radiofrequency ablation; so we put an electrode and we burned that area. Now, using this he had a freedom from seizures for about 8 to 9 months, after which he did start having a seizures back. But the whole idea was to develop the proof of concept and we were able to show that yes, ablating this area was effective. And it also allowed this individual to take a decision for a major surgery after this. Following which, once we did the surgery, was totally seizure-free. So, when we go through the steps of surgery, many times when the aetiology is complex, it may not be a single step, it could be multiple steps.
Example: Stereoelectroencephalography
11:38 Sarat Chandra
For instance, when we do the stereoelectroencephalography, most often these patients do not have any kind of substrate in imaging. It's absolutely normal and these are the really complex cases where the MRIs, even if you have done 2 or 3 times, are absolutely normal. And we are trying to localise the networks purely by putting in electrodes and then trying to correlate it with other advanced investigations like PET, MEG or ictal SPECT, and so on. And in these situations, we find that we are able to localise the networks. And we do not do surgery at the first stage, we simply burn the electrodes so that the area, the suspected area, is burned. In fact, we create a proof of concept by doing 3 steps.
Firstly, by allowing a spontaneous recording of seizures coming from that area we recorded. So, we know that seizures are arising from this area of the brain;
And in the second step, we stimulate these electrodes in order to produce habitual seizures. So when we stimulate these electrodes, they have the typical seizures which could be identified by the caregivers they say “Yes, these are the exactly kind of seizures which this person is having”;
And in the third step on the bedside itself we burn these electrodes using… we connect it to a radio frequency machine and we burn it. The patient is totally awake he doesn't feel any pain. He may hear a popping sound in his head, that's it - because when you're burning there the brain is, as you know, it doesn't have any kind of sensations it's totally…
13:00 Torie Robinson
Can you smell it?!
13:02 Sarat Chandra
No, you cannot smell it, but the patient can actually hear the popping sound. And with this, we have found that about 40% of our patients have been seizure free and they did not require a major surgery. But even if, even if - this is published data, I mean, we're not speaking about unpublished data - but even if they have recurrence of seizures, let us say after a period of 6, 7, 8 months, the duration of these patients being seizure free gives us a very good sense of confidence that this patient is going to do well following a resective surgery. And even if the patient does come back with seizures, we re-operate him after a period of 9 months or 1 year, and there is a very good probability that this patient is going to be seizure-free. So, if you see, this is a multi-step process where we are actually building up confidence with the caregivers and the patient. And we are working with them to show that we know that your disease or your pathology is complex, it's not like some simple epilepsy where you have a lesion and you take it out. We are not able to localise, but we will go by these steps and this is going to enhance our confidence to show that indeed these are the area where your abnormal networks are present.
Measuring success of an epilepsy surgery and “the burden of normalcy”
14:15 Torie Robinson
And how else do you judge the success… or how does the person with epilepsy, judge the success of a surgery? Because it's not always just about seizures, is it? It can be about mood, it can be about cognition, about their whole life.
14:27 Sarat Chandra
That’s an excellent question. So most often our primary parameter is a seizure outcome, but that is not the end of the story and that is the reason why we have a full team here. So many times, we find something called as a “burden of normalcy”. So, the person has become seizure free and then the parents or the caregivers now do not give so much of attention to him or her. They say that “You're normal, why don't you start working?”, and they find that they have been protected for their whole lives, and suddenly they're exposed to this so-called “normal”, competitive society, and they're not able to cope up with it. And they start having functional dissociative seizures. So, we find it very common in kids. You know, they have been off school for so many years because of seizures, and suddenly they're seizure-free and they're sent to school. They're not able to cope with the usual studies and they start having functional dissociative seizures. Similarly, other patients could continue having some memory issues. So when we speak about gaining memory, we tell them that “Look here, if you have seizures, and you have lost memory till now and we do surgery and your seizure stop it's not that your memory will improve, but as you age there won't be further decline of memory and as you start m, you know, progressing in life, you will start from that point. So you may not be able to catch up, but over a period of time you are going to naturally progress in everything and you're going to find improvement in those aspects.”
16:01 Torie Robinson
For instance, with temporal lobe epilepsy, I mean, that's like, for instance, really common that people have certain issues, like mental health issues, like memory issues. But when, for instance, if people have that resection, you have to cut through other tissue and it can often make memory worse, at least initially, isn't that correct?
Considering memory
16:18 Sarat Chandra
Yes. So there are many factors for taking into consideration memory loss in temporal lobe epilepsy. So firstly, is we have to be clear that the other temporal lobe is supporting your memory well. The second is, we have to know what kind of memory is the other temporal lobe supporting. Because if you see we have 2 types of memory, one is a visual memory whereby people are able to remember by looking at things and remembering them in a pictorial manner. The other is a verbal memory where you actually remember the words. So, the right temporal lobe is responsible for visual memory and the left side is responsible for verbal memory. So, if you have to do surgery for the left side, we have to ensure that the visual memory is going to be very good. Now because we know that after surgery the patient… what the patient is going to do is he would be converting his verbal memory into visual memory and that's how he's going to process it. For instance, if I tell you the word “apple” you are going to remember the word “apple”. You may not be able to, you may not visualise an apple actually, you will just remember the word “apple”. So, this is verbal memory which is registered in your left temporal lobe. But, when I say the word “apple” you may not remember the word but you will visualise the apple and that is done in the right temporal. So, for instance, if I do surgery on the left side and if I give the word “apple” so the person is first going to convert it into a pictorial, where he is going to visualise an apple and then he is going to remember in that way . So, his storage of memory is going to be in a visual form. And that's the reason, you know, whenever we operate on a temporal lobe epilepsy, we have to ensure that the opposite temporal lobe is really capable of storing this memory. Now, saying this, we also need to understand that when… particularly for people who have been having seizures for a very long time, it's not just something localised to the temporal lobe. There is some degree of collateral damage. There may be some degree of collateral damage to the rest of the brain. And this has been shown in various studies. For instance, they have shown that in patients who have long-standing temporal lobe epilepsy there is a thinning of grey matter all over the brain. So it's not just a localised. So that itself may lead to some amount of hit on cognitive issues and memory issues.
18:41 Torie Robinson
Hence the sooner we do the surgery and we identify refractory epilepsy, the better.
18:47 Sarat Chandra
Yes, absolutely.
Closing thoughts and thanks
18:49 Torie Robinson
Thank you for Sarat for going into such detail about epilepsy surgery! In our next episode - part 2 of 2 with Sarat - we are going to hear about how epilepsy surgery is evolving with new technology and new minimally-invasive techniques - including one where you just need a few plasters afterwards!! Do subscribe to support our channel - if you haven’t already - and see you next time.