Epilepsy is a common neurological disorder affecting millions worldwide.1 Although many patients' seizures can be controlled with antiepileptic medications, approximately 40% of patients with epilepsy will have breakthrough seizures despite medication or are intolerant of their medication, severely affecting their quality of life.1–3 Epilepsy surgery may offer improved seizure control for appropriately selected patients, both children and adults, with medically refractory seizures.3,4 Seizure location is paramount in determining the most effective type of epilepsy surgery for each patient.3 Around 30% to 40% of patients with medically refractory epilepsy will require some type of intracranial electroencephalography (EEG) to assist in finding the precise location of the seizure focus.1 Because of its increased popularity, stereoelectroencephalography (SEEG) will be discussed in this article.
The SEEG method was first developed in France in the 1950s by Jean Talairach (a French neurosurgeon) and Jean Bancaud (a neurologist and neurophysiologist). It evolved in the 1970s with advances in stereotactic technique and neuroradiology imaging.2,5–7 SEEG monitoring has been used in Europe for decades; only recently has it gained popularity in the US.8 The incidence of SEEG cases has increased from 28.8% in 2000 to 43.1% in 2016.1 This is an established diagnostic technique demonstrated by high accuracy and exceptional diagnostic results. This higher accuracy leads to more precise surgeries resulting in improved seizure outcomes and complication rates.3
Stereoelectroencephalography monitoring has been identified as the most effective and safe method for localizing seizure focus or foci. SEEG is an invasive surgical procedure involving the implantation of depth electrodes into the brain parenchyma to localize the focus of epileptic seizures.2–6,8–10 There are several techniques for SEEG monitoring, such as the standard frame-based, frameless, or robot-assisted devices.6 Most institutions use a conventional frame-based technique with robot-assisted stereotactic system yielding an extremely high level of accuracy and safety.3 For standard frame-based techniques, the procedure is conducted in 3 stages. First, the patient will have bone fiducial markers placed. Next, the computed tomography, magnetic resonance imaging, and/or angiography is obtained to plan the target sites for the depth electrodes. In the third stage, the stereotactic frame is applied, and electrodes are implanted with stereotactic guidance through a burr hole using the predetermined trajectory and depth based on the preoperative imaging. The numbers of electrodes and targets are customized for each patient by their noninvasive testing data. On average, a patient can have more than 10 leads, with around 12 contacts per lead spaced 2 mm apart (about 100 locations from which to record) with each lead diameter of about 1 mm. The leads are flexible with a rigid stylet, which can be removed after insertion. Once the intracranial electrodes are implanted, a routine postoperative head computed tomography is performed to confirm intracranial electrode placement and absence of hematoma.2,3,5,6,10 The patient is then admitted to the hospital and undergoes continuous EEG monitoring in the epilepsy monitoring unit (EMU) where antiepileptic medications are weaned to induce seizures. Medication adjustments and monitoring is done under the close supervision of an epileptologist. The average length of stay in the EMU after SEEG placement ranges from 3 to 28 days.5 Several seizures are needed to ensure the seizure focus or foci are confidently identified. Once enough data are collected, the individualized treatment plan can be developed.
The benefits of SEEG monitoring compared with subdural grids or strips include minimally invasive approach, ability to precisely monitor bilateral or large areas of the brain, decreased operating times, shorter recovery, increased patient comfort, and decreased infection rate. Another benefit of SEEG is that the electrodes can be removed at the bedside after adequate data have been collected and subsequent therapeutic surgery has been scheduled at the patients' convenience.4–6,9
Although complication rates are generally low, there is risk to the procedure.8 The rates of reported complications differ widely from 0% up to 26.3%. The reason for the variation is likely due to the definitions of complications and the study methods.5 However, despite the differing studies, hemorrhage/hematoma is the most common complication. The second is infection, although still low in most studies.3,6,8,9 The morbidity reported with SEEG monitoring varies from 0% to 7.5% and is mostly related to hemorrhagic or infectious complications. Permanent neurological deficits were found to be rare but can occur.8,9 Usually, mortality is directly related to intracerebral hematoma. Complications were found to be higher in patients with a history of previous craniotomy, an increased number of electrodes, and a longer duration of monitoring.8 Patients who develop complications may require further surgery, including hematoma evacuation, premature electrode removal, and washout for infection.
Nurses play a key role in the care of the SEEG patient and may have an impact on morbidity. The care of the epilepsy patient with SEEG monitoring is individualized including medications, physical examination, and medical and seizure history.2 Patients are closely monitored in an EMU, which may include cameras in the patient room for visualization or direct supervision such as a sitter/relative.2 Sometimes, having a relative at the bedside may be beneficial, especially in children and those patients with agitation.11 Nurses should be aware of and monitor for adverse events and potential complications including pain, nausea/vomiting, hemorrhage, infection, and electrode dislodgement. Furthermore, patients are at risk for secondary complications such as falls, deep vein thrombosis, and possible pulmonary embolus secondary to immobility.2,3,11,12 Clinical monitoring should include neurological assessments, wound care, pain assessment, vital signs, patent intravenous access, seizure precautions, and ensuring equipment is intact and functioning appropriately.2,11
Because the most threatening postoperative complication is hemorrhage, it is imperative that the nurse perform serial monitoring for neurological decline such as decreased mental status or development of a focal neurological deficit.2,11 The bedside nurse can help reduce the risk of hemorrhage by achieving goal blood pressure control with close monitoring and aggressive treatment. Patients with a higher risk of hemorrhage include those with coagulopathies, thrombocytopenia, and use of antithrombotic agents. Obtaining a detailed history is helpful in assessing those at a higher risk and ensuring medications with antithrombotic properties are avoided while leads are in place.2
Another important postoperative complication is infection. It is important that the patients receive postoperative antibiotics as prescribed, while the leads are in. In addition, the prevention of cerebrospinal fluid leak can impact infection rates. Comorbidities can also contribute to a higher risk for infections such as age, immunocompromise, diabetes, or other medical conditions.2 Therefore, the nurse should closely monitor for fever, redness, swelling, and drainage at incision sites.2,9,11
Patients are also at risk for electrode dislodgment postoperative. Dislodgement is important because the process of electrode insertion is multistep (as described previously) and with an associated risk of hemorrhage for each insertion.2 Once dislodged or pulled out accidentally, the electrodes are not able to be put back in. To reduce the risk of electrode dislodgment, the nurse can do wound checks and ensure the electrodes are secured in a place that is not at the risk of being pulled out by the patient. The following precautions can be taken: (1) wrap the electrodes up in the head dressing without loops hanging out, (2) ensure the external EEG cables that tether the patient to the wall are long enough to reach the bathroom to avoid tension on the cables, (3) untangle the cables as needed, and (4) keep the room free of clutter. Nurses should educate the patient and families about the importance of not pulling on the electrodes, scratching, or removing the head wrap. If the wound needs to be redressed, only certified personnel, usually the EEG techs, should do the dressing changes with nursing assistance.2,12
Continuing education for the epilepsy patients and families by the interdisciplinary team is imperative. It has been demonstrated that acute care nurse practitioners who engage in the care and monitoring of the epilepsy patient offer a special skill set of clinical expertise that is beneficial to the patients' quality of care. The acute care nurse practitioner may also improve the patient's knowledge, compliance, and quality of life.13 Specialist epilepsy nurses also have increased knowledge and are trained with extra neurology qualifications to provide improved quality of care and personalized epilepsy education and care.13
Stereoelectroencephalography has an estimated cost effectiveness of 75% to 88% compared with medical therapy alone.9 Because of advancements in therapy such as SEEG, patients with medically refractory seizures are now able to undergo customized surgical procedures that can significantly reduce seizure severity and frequency.3,9 Epilepsy surgery options include surgical resection and/or insertion of neuromodulation devices such as the vagus nerve stimulator and/or responsive neurostimulation device. Most efficacious procedures can result in complete seizure freedom in two-thirds of patients, whereas others have a more modest decrease in seizures.9,10 Surgery can improve patient quality of life and decrease their morbidity/mortality rate.3 Nurse education and care of the SEEG monitoring patient can facilitate the prevention of complications and adverse events, which impacts morbidity and length of stay while improving patient outcome and satisfaction.3,13
1. Abou-Al-Shaar H, Brock AA, Kundu B, Englot DJ, Rolston JD. Increased nationwide use of stereoencephalography for intracranial epilepsy electroencephalography recordings. J Clin Neurosci
2. Dilorenzo DJ, Byrne RW, Bleck TP. Postoperative care of the epilepsy patient with invasive monitoring. In: Kumar M, Levine J, Schuster J, Kofke A, eds. Neurocritical Care Management of the Neurosurgical Patient
. Philadelphia, PA: Elsevier; 2018:231–240.
3. Van der Loo LE, Schijns O, Hoogland G, et al. Methodology, outcome, safety and in vivo accuracy in traditional frame-based stereoelectroencephalography. Acta Neurochir
. 2017;159(9):1733–1746. doi:10.1007/s00701-017-3242-9
4. Minotti L, Montavont A, Scholly J, Tyvaert L, Taussig D. Indications and limits of stereoelectroencephalography (SEEG). Neurophysiol Clin
. 2018;48(1):15–24. doi:10.1016/j.neucli.2017.11.006
5. Gonzalez-Martinez J, Mullin J, Vadera S, et al. Stereotactic placement of depth electrodes in medically intractable epilepsy. J Neurosurg
6. Iida K, Otsubo H. Stereoelectroencephalography: indication and efficacy. Neurol Med Chir (Tokyo)
. 2017;57(8):375–385. doi:10.2176/nmc.ra.2017-0008
7. Reif PS, Strzelczyk A, Rosenow F. The history of invasive EEG evaluation in epilepsy patients. Seizure
8. Schmidt RF, Wu C, Lang MJ, et al. Complications of subdural and depth electrodes in 269 patients undergoing 317 procedures for invasive monitoring in epilepsy. Epilepsia
. 2016;57(10):1697–1708. doi:10.1111/epi.13503
9. Garcia-Lorenzo B, Del Pino-Sedeno T, Rocamora R, Lopez JE, Serrano-Aguilar P, Trujillo-Martin MM. Stereoelectroencephalography for refractory epileptic patients considered for surgery: systematic review, meta-analysis, and economic evaluation. Neurosurgery
10. Gonzalez-Martinez J, Bulacio J, Thompson S, et al. Technique, results, and complications related to robot-assisted stereoelectroencephalography. Neurosurgery
11. Chassoux F, Navarro V, Catenoix H, Valton L, Vignal JP. Planning and management of SEEG. Neurophysiol Clin
. 2018;48(1):25–37. doi:10.1016/j.neucli.2017.11.007
12. Ronald Regan UCLA Department of Nursing. Population/specialty guidelines, neuroscience: epilepsy monitoring in adults—phase I and phase II. Available at http://aann.org/uploads/Membership/SFG/epilepsy/Nur-G3127_Phase_I_and_II.pdf
. Accessed August 8, 2019.
13. Hill CE, Thomas B, Sansalone K, et al. Improved availability and quality of care with epilepsy nurse practitioners. Neurol Clin Pract
. 2017;7(2):109–117. doi:10.1212/CPJ.0000000000000337