THIS PRESENTATION IS ABOUT THE SELECTION OF CANDIDATES FOR EPILEPSY SURGERY

1. WHICH PATIENTS OF EPILEPSY
REQUIRE EARLY NEUROSURGICAL
REFERRAL AND
HOW I MANAGE THEM
DR, ARGHYA DEB
DM (NEUROLOGY) RESIDENT
BANGUR INSTITUTE OF NEUROSCIENCES
KOLKATA

2. INTRODUCTION
Epilepsy surgery is generally understood to mean resective Sx.
The primary surgical aim is to control of seizures rather than the
underlying pathology causing seizures (e.g. brain tumour).
Up to 30% of patients with epilepsy are pharmacoresistant.
Surgery becomes a viable treatment alternative in up to half of
the patient population with refractory focal epilepsy.
It carries the promise of seizure freedom, a reduction in seizure
or medication-related morbidity, and a reduction in the risk of
sudden unexpected death (SUDEP).

3. EPILEPSY SURGERY: HISTORICAL ASPECT
Engel (1993) divides epilepsy surgery into three
historical phases-
 Phase-1: Lesion-directed surgery
 Phase-2: EEG-directed surgery
 Phase-3: Imaging (lesion)-directed surgery

4. EPILEPSY SURGERY: PIONEERS
Sir Victor Horsley (1857–1916), a
remarkable man and first rate
scientific investigator, performed
the first resective surgery (a cortical
resection for partial epilepsy based
on clinical localization) on
26.05.1886 at Queen Square,
London.

5. EPILEPSY SURGERY: PIONEERS (CONT.)
 Later, Sir Wilder Penfield (1891-1976) with
his colleague Herbert Jasper, invented
the ”Montreal procedure” which allowed
patients to remain awake and describe
their reactions while the surgeon
stimulated different areas of the brain
(Functional mapping).
 In this way he could more accurately
target the areas of the brain responsible
for seizure, reducing the side-effects of
the surgery.

6. FURTHER PROGRESS IN EPILEPSY SURGERY
Advances in neuroanesthesiology, antisepsis, neurophysiology,
neuroimaging, and surgical instruments had started to boost
the progress in resection surgeries.
In the late 1930s, Penfield described the first case of
intracranial EEG monitoring for surgical treatment of epilepsy.
Which along with the clinical localization, allowed a greater
number of patients to undergo resection.
This ‘ electroclinical ’ localization of the ‘ epileptic focus ’
became and remains the cornerstone of epilepsy surgery.

7. EPIDEMIOLOGICAL BACKGROUND
Various epidemiological studies have been carried out to
identify who might be the suitable candidate for epilepsy
surgeries.
Crude incidence of Epilepsy = 50-100 per 100,000
populations
Crude prevalence = 5-8 per 1,000 populations
Studies have identified that nearly 3% of new cases of
epilepsy may prove to be suitable candidate for epilepsy
surgeries.

8. PRESURGICAL ASSESSMENT

9. SUITABLE CANDIDATES
Partial onset seizure that are intractable to medical therapy
Frequency on an average at least 1/month
Age < 60 years
Has no epilepsy etiology which is a contraindication for
surgery.

10. AIMS OF PRESURGICAL ASSESSMENT
1. To confirm that the patient medically intractable epilepsy
2. To define the outcome goals of the chosen surgical
procedure (e.g. seizure freedom, 50% reduction) and
estimate the chances of attaining this successful outcome
3. To define the likely gains in terms of quality of life if surgery is
carried out.
4. To determine that the person is medically fit for surgery
5. To counsel the patient appropriately about the outcome and
risks

11. AIMS OF PRESURGICAL ASSESSMENT (CONT.)
6. To determine the risks of carrying out the surgical
procedure, e.g. in terms of mortality, neurological
morbidity, psychological and social effects; also the risks
of not operating
 The patient must feel confident that sufficient
information has been given, and that this information is
accurate and unbiased.
 Surgery should never be performed if the patient is
reluctant or undecided.

12. SELECTION OF THE PATIENT

13. 1. MEDICALLY INTRACTABLE EPILEPSY
Active epilepsy for 5 years (or less in severe epilepsy) in spite
of adequate trials of therapy with 3 or more mainline AEDs,
and if seizures are frequent (>1/month).
Recent trend- define intractability earlier – after 2 or 3 years of
failure to respond to medical therapy (early failure of
treatment predicts continuing poor response).
The merits of each case should be considered individually, and
this requires skill and experience.

14. 2. ESTIMATING THE SEIZURE OUTCOME AFTER
SURGERY AND THE RISKS OF SURGERY
The estimate of outcome will depend on the severity of the
epilepsy, and its underlying anatomical & physiological basis.
A common example is the ~60% chance of freedom from
seizures after a modified anterior temporal lobectomy in an
uncomplicated case of mesial temporal epilepsy.
The surgical risk depends on the nature of the surgery, and
extent & the location of brain resection.
The estimates of risk and outcome should be given in writing
to the patient.

15. 3. QUALITY-OF-LIFE GAIN
Surgery should be offered only to those whose quality of life is
seriously compromised by the occurrence of seizures, and
In whom the expected outcome of surgery is likely to result in
major overall improvement in the quality of life.
But it is often difficult to decide.
The focus of this assessment should be broader than simple
seizure control.
Skilful counselling is vital in this area.

16. 4. NON - EPILEPTIC SEIZURES
Generally, non - epileptic attacks (NEA), even in combination
with genuine attacks, are a contraindication for surgery.
If surgery is carried out in patients with a combined attacks,
the psychogenic attacks frequently worsen even if the genuine
attacks are controlled.
Decisions about surgical treatment in this area should be
made only in a specialist setting.

17. 5 (A). LEARNING DISABILITY
Learning disability (a full-scale IQ < 70) often indicates
widespread cerebral dysfunction and resective surgery is less
likely to control seizures even if a single lesion is demonstrable.
In multiply handicapped individuals, control of seizures will not
necessarily lead to major gains in QOL.
Finally, ‘ cerebral reserve ’ may be lower in people with learning
disability.
Expert evaluation is necessary and the risk–benefit equation
needs careful formulation.

18. 5 (B). BEHAVIOURAL DISORDER
Surgery is generally also contraindicated in individuals
who show severely dysfunctional behaviour.
Specially, if it is likely that the patient will be unable to
• Tolerate the intensive presurgical evaluation
• Make informed and considered judgements about the
potential risks and benefits of epilepsy surgery
• Exploit the opportunities afforded by successful surgery.

19. 5 (C). PSYCHOSIS
The presence of a chronic interictal psychosis is also generally
a contraindication to surgery.
As the psychosis can worsen dramatically after surgery.
Decisions about surgical treatment should not be made by
severely depressed patients.
Psychosis and depression may also prevent informed consent.
Again, individual decisions in this situation require a detailed
assessment by an experienced practitioner.

20. MEDICAL FITNESS AND AGE
Added risks due to general medical problems, e.g. cervical,
spinal or vascular disease.
Surgery should be contemplated only in those who can
withstand prolonged anaesthesia.
Surgery is not commonly carried out in those aged > 50 years,
In the older patient, lifestyle is often well adapted to the
epilepsy and may be difficult to change
The reduction in cerebral reserve can be more critical in older
age groups.

21. THE TIMING OF EPILEPSY SURGERY
In recent years, surgery is recommended at an early stage.
This is to minimizes the impact of the seizure disorder on
education and social development.
To minimize the potential for morbidity or death due to
epileptic seizures.
To prevent the possibility of secondary epileptogenesis (either
through injury or ‘ kindling ’ effect ) and the possibility of
progressive intellectual or behavioural decline.
To minimize the cognitive and psychological impact of
epilepsy.

22. SPECIAL CONSIDERATION IN CHILDREN
Recommendation for early surgery applies particularly in
children and for surgically remediable childhood epilepsy.
Seizure may pose additional risk to the developing brain.
Uncontrolled seizures also jeopardize the chance of an
independent lifestyle, and children with intractable epilepsy
are likely to be excluded from normal educational, social and
vocational opportunities.