The Utility of NIOM During LITT for Refractory MTLE
The Utility of NIOM During LITT for Refractory MTLE
Mesial temporal lobe epilepsy (MTLE) is the most common cause of medication-resistant
 epilepsy in adults, and MRI-guided laser interstitial thermal therapy is a new approach to
 its surgical management; however, while LITT demonstrates fewer complications than
 traditional surgical techniques, it generates lower rates of seizure freedom. During
 traditional temporal lobectomy for MTLE, neurophysiologic intraoperative monitoring (NIOM)
 can be used to better identify epileptogenic tissue and guide resection. Our study proposes
 to investigate the utility of NIOM during LITT for MTLE. Subjects will be drawn from
 refractory mesial temporal lobe epilepsy patients determined to be candidates for LITT.
 During their LITT surgery, in addition to the placement of the stereotactic LITT probe,
 subjects will receive a second smaller stereotactic electrode for intraoperative monitoring
 of epileptic discharges before and after surgery. After surgery, at regularly scheduled
 follow-ups, patients will receive the Quality of Life in Epilepsy questionnaire (QOLIE-31-P),
 in addition to standard post-operative care. Endpoints will be surgical complications,
 fractional decrement in epileptiform discharges from pre- to post-ablation recordings, and
 surgical outcome at 6 months and one year. Analysis of severe complications will be expressed
 as a simple complication rate, for overall complications, severe complications, and
 hemorrhagic complications in specific. The relationship between fractional discharge
 decrement and outcome will be assessed by regression analysis. Risks of the study will stem
 from the placement of the stereotactic electrode for intraoperative monitoring, which
 represents a small incremental risk beyond typical LITT for MTLE.
Mesial temporal lobe epilepsy (MTLE) is the most common cause of medication-resistant
 epilepsy in adults. The standard treatment for refractory MTLE is surgical resection by
 craniotomy. Stereotactic laser interstitial thermal therapy (LITT) is a new surgical
 technique being used to treat MTLE. Under MRI-guidance, a laser probe is inserted into the
 seizure focus and heat is used to destroy the tissue. Compared to temporal lobectomy, LITT
 results in shorter hospital stays, low complication rates, and possibly less cognitive
 decline; however, seizure freedom rates are potentially lower.

 During temporal lobectomy, neurophysiologic intraoperative monitoring (NIOM) can be used to
 better identify epileptogenic tissue and guide resection. This tool has been unavailable
 during LITT procedures. Recently, the investigators demonstrated in two cases that NIOM with
 a depth electrode is technically feasible during LITT and can identify epileptiform activity
 intra-operatively.

 This is a prospective trial of NIOM during LITT for mesial temporal lobe epilepsy. The
 investigators will assess the safety of performing NIOM during LITT and whether data from
 NIOM (frequency and characteristics of epileptiform discharges recorded before and after
 ablation) are associated with seizure outcomes. If there is an association, NIOM could be
 used for prognostication and could potentially even be used to guide surgery.

 Hypotheses:

 1. NIOM performed by MRI-guided stereotactic depth electrode placed in the parahippocampal
 gyrus adjacent to the LITT catheter is safe, as compared to institutional LITT controls
 without NIOM and published LITT complication rates.

 2. Greater magnitude fractional decrements in discharge frequency from pre-ablation to
 post-ablation recordings will be significantly associated with better seizure outcomes,
 as measured by International League Against Epilepsy (ILAE) surgical outcome scores.

 Objectives:

 The primary project goals are to assess if NIOM by parahippocampal depth electrode is safe
 during LITT of MTLE and to assess if the fractional decrement of interictal discharges (ID)
 on NIOM can be significantly correlated with outcome. The study will be powered to address
 these questions a priori. Post hoc analyses consisting of a multivariate analysis of other
 patient demographic data, NIOM findings, operative parameters, quality of life scores, and
 neuropsychiatric outcomes will also be assessed.
Inclusion criteria are as follows

 1. Age ≥ 18

 2. The patient must suffer from drug resistant mesial temporal lobe epilepsy as
 determined by a consensus of providers at weekly epilepsy surgery conferences held by
 the Duke Epilepsy Center

 3. The patient must be a candidate for LITT for MTLE as determined by a consensus of
 providers at weekly epilepsy surgery conferences held by the Duke Epilepsy Center

 Exclusion criteria are as follows

 1. Age ≤ 18

 2. Lack of consensus on localization of MTLE

 3. Multifocal epilepsy

 4. History of prior epilepsy surgery

 5. Lack of consensus on candidacy for LITT

 6. Pregnancy

 7. Patient without capacity to provide legal consent