Executive Summary
Epilepsy is becoming widespread in the healthcare sector, with the majority of patients suffering from related seizures. According to Samanta (2022), epilepsy is the most common among neurological disorders with a significant prevalence. That is to say, the likelihood of a patient with a neurological ailment being diagnosed with epilepsy is high. Even though no permanent cure is yet to be invented, many forms of treatment are available to control and mitigate the condition, including drugs and surgery. However, some victims have drug-resistant epilepsy and thus depend on surgery as the last medical resort.
Epileptic surgery is done by resecting the epileptogenic tissue believed to cause seizures in the brain. Medical operations are delicate because essential parts of the brain that control neuropsychological and other vital functions must be spared. As a result, proper pre-surgical evaluation of patients is necessary before commencing the operation.
Since epilepsy attacks specific parts of the brain, it is necessary to assess and identify the particular areas affected for surgical removal. In the same vein, not all epileptic patients are clinically eligible for surgery, as some may not meet the suitability criteria for various reasons. In addition, epilepsy may attack delicate regions of the central nervous system that control essential activities (Guo et al., 2022).
It is therefore critical to thoroughly evaluate individuals before proceeding with the operation. Several evaluation steps are in place for candidates of epileptic surgery, including phase I and II, with each stage having a set of tests performed. The study analyzes in depth the evaluation steps undertaken before epileptic surgery, reviews the literature on the methods used, and concludes with a summary.
Introduction
Seizures are sudden attacks sustained by epileptic victims, originating from parts or sections of the brain affected by epilepsy. Surgery is the medical resection of one or some parts of the central nervous system, established to cause epileptic seizures. Evaluation, on the other hand, is the advanced medical assessment of surgical candidates to locate the point of attack in the brain before undergoing surgery for resection.
Literature Review and Methodology
Due to the prevalence of epilepsy, treatment options have been essential topics in the medical field, as research is done to develop effective management of the condition. With the ineffectiveness of drugs, surgical treatment has been a topic of interest (Ramezani et al., 2022). As a result, several studies have been conducted on epileptic surgery, analyzing the efficacy, surgical criteria, and developments in the area. In addition, pre-surgical evaluation, an essential step in the surgical journey, has been a subject of interest for researchers.
Previous studies have discussed the evaluation steps for epileptic surgery (Pillay et al., 2022). While several studies have been conducted on the same topic, there is still room for further research. Therefore, this study will analyze the critical steps in evaluating epilepsy surgery. The research will draw on past academic journals on the topic and clinical guidelines from healthcare bodies such as the Centers for Disease Control and Prevention (CDC), among others, in its analysis and discussion. The academic journals targeted for use are the latest, relevant, and contain credible information as approved by several scholars.
Diagnostic EMU Evaluation
Before a patient is evaluated for epileptic surgery, the medical practitioners must first determine whether or not the medical experiences and events are epileptic seizures and if the attacks require surgery. The pre-evaluation is necessary since some events may be confused as epileptic seizures when they are not, thus leading to wrong evaluation and surgery (Mulligan & Carniello, 2022). Even though this procedure is not widely considered to be among the pre-surgical evaluation steps, it is technically the first step of assessment for epilepsy surgery. Some of the examinations in the pre-surgical stage include;
Phase I
Phase I is the first step of pre-surgical evaluation. At this stage, a surgical candidate undergoes various tests to determine whether the seizures originate from a single area. Using multiple medical tests, epileptic convulsions are evaluated to confirm if they originate from the same part of the brain. To check this, 3-5 attacks of the surgical candidate are tested to locate their point of origin in the central nervous system (Becker et al., 2022). Phase I assessment uses various clinical techniques and procedures in its evaluation. Some of the evaluation practices and associated tests in this period include;
SPECT Study
A SPECT study is a unique brain scan procedure done on the central nervous system. SPECT is an acronym for Single Photon Emission Computed Tomography (SPECT); the procedures use a radioactive isotope in its assessment. During an attack, a small amount of a radioactive isotope is injected into the victim, then it travels to the seizure’s origin in the brain (López et al., 2022). The element can locate the point of origin of an attack (Siriratnam et al., 2022). After some hours in the brain, the isotope is eliminated safely. The procedure is essential and safe, so no precautions are required after the injection.
MRI of the Brain
The second procedure in the phase I evaluation is MRI. A high-resolution MRI is performed on a surgical candidate to assess for structural abnormalities or lesions in the brain that may be causing the seizures (Chari et al., 2022). Since some episodes are not epileptic, it is essential to evaluate if the suffered attacks are epileptic or caused by dysfunctional brain activity because abnormal structuration of the brain may also trigger convulsions (Baxendale et al., 2022). The test will therefore expose the presence of any abnormal structuration.
Inter-Ictal PET Scan
The third test in the phase I evaluation is the Inter-ictal PET scan. Like the SPECT scan, the PET scan uses the radioactive isotope in its brain assessment. PET, an abbreviation for Positron Emission Tomography, detects abnormal brain function (Sun et al., 2022). Unlike an MRI scan, which reveals abnormal structures, this test assesses abnormal brain physiology (Yossofzai et al., 2022). The Interictal PET scan reveals abnormal brain function. The test is safe and commonly conducted as an outpatient study.
Neuropsychological Analysis
A surgical candidate undergoes neuropsychological tests following the structural brain tests during the phase I evaluation. The examination focuses on the functions of the nervous system and its effectiveness. Since epilepsy may negatively affect and alter the psychological roles of the brain, it is necessary to assess the extent of the impact of the condition (Campbell et al., 2022). Under neuropsychological examination, an epileptic patient is evaluated on thinking, problem-solving, reading, visual identification, language, and other cognitive functions of the brain. The test aims to identify the areas of weakness that are believed to be the strong points of attack.
Psychiatric Analysis
After the neuropsychological assessment, a psychiatric examination is a subsequent step. Under this procedure, a surgical candidate is subjected to a psychiatric analysis to assess their emotional status. Epileptic victims may experience psychological challenges such as depression and suicidal thoughts (Kaur et al., 2022). The emotional problems can have either an individual impact on the patient or affect the family and their environment. Besides, drugs for treating epilepsy occasionally trigger psychological disorders, including depression and stress, among other challenges (Kaestner et al., 2022). Due to this, surgical candidates must undergo psychiatric assessment to establish their emotional status and the psychological needs they may require thereafter.
WADA Test and Angiogram
Wada Test and Angiogram are other examinations done on surgical candidates in the phase I evaluation. Coined from Dr. Juhn Wada’s name, the assessment is conducted on patients when they are actively awake. Wada examination is done by inducing an anesthetic drug into the patient through their carotid arteries via the angiogram, thus the name. The pill temporarily halts language or memory function in a specific brain part. After administering the drug, the patient is subjected to language and other cognitive examinations to establish which part of the brain performs the roles.
Functional MRI
Functional MRI is the subsequent test done after the Wada Test. The assessment is intended to understand the way the brain of a surgical candidate works. Targeting the brain, the examination measures the changes in blood and other neural activities in the central nervous system (Podkorytova et al., 2022). The assessment is necessary as it helps avoid interference with the brain’s essential functions during the surgery. Since the operation involves resectioning some part of the nervous system, knowing which parts of the brain are responsible for essential brain activities is critical.
MEG
Magnetoencephalogram (MEG) is the next step in pre-surgical evaluation for epileptic surgery. The MEG procedure depends on the magnetic field for examination. For this test, the magnetic fields produced by the electrical activity in the brain are recorded using a special machine (Lozano-García et al., 2022).
As the electroencephalogram, the magnetic fields are generated by the underlying electrical changes in the nervous system (Kakinuma et al., 2022). Furthermore, MEG (electroencephalography is an alternative test for assessing brain waves that uses electrodes. The EEG can expose abnormal electrical activity in the central nervous system if run on an epileptic patient.
Surgery Conference
The final test in the phase I evaluation is the surgery conference. Following all the tests, the medical team meets to discuss the results of the various examinations. Experts from all the departments that undertook the test, including neurologists, neurosurgeons, psychiatrists, psychologists, neuro-radiologists, case managers, and EEG technologists, meet together to analyze the results in unison, assess the information, and decide the way forward (Khoo et al., 2022). In addition, they share the results with the patient and family and inform them of the next course of action. Depending on the results, the medical team advises the patient and family on what to do.
Even though these are the commonly conducted tests in the phase I evaluation, it is worth noting that different hospitals have distinct policies and machines and thus may vary in their evaluation procedures. Various healthcare units have varying levels of technology and experts; hence, pre-surgical assessment may take various forms as some overlook other examinations or perform jointly (Jehi et al., 2022). In the same vein, continuous development in medical technology is bringing up new forms of evaluation, replacing the old examination techniques. As a result, different hospitals may slightly vary in the evaluation examination depending on technological advancement.
Phase II
The second step of evaluation in epilepsy surgery is phase II. The outcome of the phase I examination determines the activities and tests in the second stage. Following the completion of the evaluation phase, the medical team may feel the tests are not enough and subject the surgical candidate to more intensive monitoring. If they decide to conduct monitoring, the surgical candidate is subjected to continuous video-EEG monitoring with intracranial electrodes to assess the strength and level of the seizure (Sullivan et al., 2022). Since this is a complex test, surgery may be needed to implant the electrodes into the nervous system. Despite the surgical procedure, the test does not form part of the epileptic surgery but is a pre-surgical evaluation.
Video-EEG monitoring devices can locate the points where the convulsion starts. Since an attack can originate from several points in the brain, the procedure is critical in locating the exact location and establishing if the attack may be coming from several areas in the nervous system (Tamimi et al., 2022). It is vital to establish the source of the attack to know which part to remove during the surgery (Gadot et al., 2022).
In cases where the convulsions come from more than one or several areas in the part of the brain, the resection may be complicated since numerous regions may need to be removed to eliminate the attack. However, this can be challenging considering the essential roles performed by the central nervous system (Cao et al., 2022). It even gets more complicated if it is established that the convulsions originate from the part of the brain performing essential activities such as cognitive functions.
Conclusion
Surgery is the most common and effective treatment option for epilepsy, with many patients embracing the meditation technique. Epileptic surgery involves resectioning the part of the brain that causes the seizure or where the convulsion originates. Medical exercise is a delicate procedure that considers the essentiality of the central nervous system. To have effective surgery and avoid costly mistakes that may be committed during the procedure, it is necessary to conduct a pre-surgical evaluation to assess significant medical concerns, such as the source of the seizure, the emotional impact of the episode, the psychological aspects, and the various parts of the brain pathologically affected by epilepsy.
The evaluations are done in phases I and II, with each step having distinct assessment practices. Several tests, including psychiatric analysis, psychological analysis, SPECT study, WADA test, MEG, brain MRI, and surgical conference, are conducted on surgical candidates in phase I before the epileptic surgery exercise. Following phase I and the result, a surgical candidate is subjected to phase II for further assessment, after which they are taken to the epileptic surgical procedure for resection.
References
Baxendale, S., & Baker, G. A. (2022). Uses and abuses of the neuropsychological assessment in the pre-surgical evaluation of epilepsy surgery candidates. Epilepsy & Behavior Reports, 18, 100507.
Becker, J. E., Denney, D. A., Bordes Edgar, V., & Carlew, A. R. (2022). Cross-cultural pre-surgical epilepsy neuropsychological evaluations in bilingual adults. Journal of Health Service Psychology, 48(3), 99-106.
Campbell, J. M., Kundu, B., Lee, J. N., Miranda, M., Arain, A., Taussky, P., Grandhi, R. & Rolston, J. D. (2022). Evaluating the concordance of functional MRI-based language lateralization and Wada testing in epilepsy patients: A single-center analysis. Interventional Neuroradiology.
Cao, M., Galvis, D., Vogrin, S. J., Woods, W. P., Vogrin, S., Wang, F., Woldman, W., Terry, J. R., Perterson, A., Plummer, C. & Cook, M. J. (2022). Virtual intracranial EEG signals reconstructed from MEG with potential for epilepsy surgery. Nature Communications, 13(1), 994.
Chari, A., Adler, S., Wagstyl, K., Seunarine, K., Marcus, H., Baldeweg, T., & Tisdall, M. (2022). The ideal approach to the evaluation of machine learning technology in epilepsy surgery: Protocol for the MAST trial. BMJ Surgery, Interventions, & Health Technologies, 4(1).
Gadot, R., Korst, G., Shofty, B., Gavvala, J. R., & Sheth, S. A. (2022). Thalamic stereoelectroencephalography in epilepsy surgery: A scoping literature review. Journal of Neurosurgery, 1(aop), 1-16.
Guo, J., Hu, X. B., Yao, L., Lv, S. M., Lv, J. H., Wang, X. Y., Guo, M. J., Kong, Y., Liu, R.H. & Kong, Q. X. (2023). Seizure outcome after surgery for refractory epilepsy diagnosed by 18F-FDG PET/MRI: A systematic review and meta-analysis. World Neurosurgery.
Jehi, L., Jette, N., Kwon, C. S., Josephson, C. B., Burneo, J. G., Cendes, F., Sperling, R. M., Baxendale, S., Busch, M. R., Triki, C. C., Cross, J. H., Ekstein, D., Englot., J. D., Luan, G., Palmini, A., Rios, L., Wang, X., Roessler, K., Rydenghag, B. … Wiebe, S. (2022). Timing of referral to evaluate for epilepsy surgery: Expert consensus recommendations from the surgical therapies commission of the international league against epilepsy. Epilepsia, 63(10), 2491-2506.
Kaestner, E., Pedersen, N. P., Hu, R., Vosoughi, A., Alwaki, A., Ruiz, A. R., Staikova, E., Hewitt, C. K., Epstein, C., McDonald, R. C., Gross, E. R. & Drane, D. L. (2022). Electrical Wada for pre‐surgical memory testing: A case report. Epileptic Disorders, 24(2), 411-416.
Kakinuma, K., Osawa, S. I., Hosokawa, H., Oyafuso, M., Ota, S., Kobayashi, E., Kawakami, N., Ukishiro, K., Jin, K., Ishida, M., Sato, T., Sakamoto, M., Niizuma, K., Tominaga, T., Nakasato, N. & Suzuki, K. (2022). Determination of language areas in patients with epilepsy using the super-selective Wada test. IBRO Neuroscience Reports, 13, 156-163.
Kaur, N., Nowacki, A. S., Haut, J. S., Klaas, P., Ferguson, L., Lachhwani, D., Bingaman, W., Lineweaver, T. T. & Busch, R. M. (2022). Cognitive outcomes following pediatric epilepsy surgery. Epilepsy Research, 180.
Khoo, A., Martin, L., de Tisi, J., O’Keeffe, A. G., Sander, J. W., & Duncan, J. S. (2022). Cost of pre-surgical evaluation for epilepsy surgery: A single-center experience. Epilepsy Research, 182, 106910.
López, E. K. C., Aparicio, J., Valera, C., Plana, J. C., Camacho, A. R., Fons, C., & Arzimanoglou, A. (2022). Pre-surgical evaluation challenges and long-term outcome in children operated on for Low-Grade Epilepsy Associated brain Tumors. European Journal of Paediatric Neurology, 41, 55-62.
Lozano-García, A., Hampel, K. G., Gutiérrez, A., Villanueva, V., Cano-López, I., & González-Bono, E. (2022). Clinical utility of Epitrack for differentiating profiles and patterns of post-surgical change in memory and quality of life in patients with drug-resistant epilepsy. Applied Neuropsychology: Adult, 1-12.
Mulligan, B. P., & Carniello, T. N. (2023). A procedure for predicting, illustrating, communicating, and optimizing patient-centered outcomes of epilepsy surgery using nomograms and Bayes’ theorem. Epilepsy & Behavior, 140, 109088.
Pillay, S. B., Gross, W. L., Janecek, J. K., Binder, J. R., Oleksy, A. J., & Swanson, S. J. (2023). Reliable change on the selective reminding test in a series of left-hemisphere language dominant patients with right temporal lobe epilepsy. Epilepsy & Behavior, 138, 109004.
Podkorytova, I., Hays, R., Perven, G., & Lindstrom, S. A. (2022). Epilepsy surgery in a patient with monogenic epilepsy related to SCN8A mutation. Epilepsy & Behavior Reports, 18.
Ramezani, A., Johnson, M., Alvani, S. R., Odor, A., & Hosseinpoor, S. (2022). The P3-model of perioperative psychological preparation: Pre-surgical and pre-medical procedural psychological preparation and psychophysiological interventions. Clinical Neurology and Neurosurgery, 107468.
Samanta, D. (2022). The role of implementation science in improving epilepsy surgery utilization. Epilepsy & Behavior, 130, 108669.
Siriratnam, P., Foster, E., Shakhatreh, L., Neal, A., Carney, P. W., Jackson, G. D., O’Brien T.J., Kwan P., Chen Z., & Ademi, Z. (2022). The effect of epilepsy surgery on productivity: A systematic review and meta‐analysis. Epilepsia, 63(4), 789-811.
Sullivan, J., Deighton, A. M., Vila, M. C., Szabo, S. M., Maru, B., Gofshteyn, J. S., James, E. S., Rico, S. & Zuberi, S. M. (2022). The clinical, economic, and humanistic burden of Dravet syndrome–A systematic literature review. Epilepsy & Behavior, 130.
Sun, Y., Song, Y., Ren, H., Zhu, H., Wang, Y., Li, X., Yan, W. & Wang, Y. (2022). Synchronization clusters located on epileptic onset zones in neocortical epilepsy. Acta Epileptologica, 4(1), 1-9.
Tamimi, A., Juweid, M., & Tamimi, I. (2022). Recent advances in epilepsy surgery.
Yossofzai, O., Fallah, A., Maniquis, C., Wang, S., Ragheb, J., Weil, A. G., Brunette-Clement, T., Andrade, A., Ibrahim, M. G., Mitsakakis, N. & Widjaja, E. (2022). Development and validation of machine learning models for prediction of seizure outcome after pediatric epilepsy surgery. Epilepsia, 63(8), 1956-1969.