Single-center cost comparison analysis of stereoelectroencephalography with subdural grid and strip implantation

View More View Less
  • 1 Department of Neurological Surgery, Washington University in St. Louis, St. Louis, Missouri;
  • | 2 Department of Neurological Surgery, Division of Pediatric Neurosurgery, University of Nebraska Medical Center, Omaha Children’s Hospital, Omaha, Nebraska; and
  • | 3 Department of Neurosurgery, Johns Hopkins University, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida
Free access

OBJECTIVE

Use of invasive stereoelectroencephalography (SEEG) has gained traction recently. However, scant research has investigated the costs and resource utilization of SEEG compared with subdural grid (SDG)–based techniques in pediatric patients. Here, the authors have presented a retrospective analysis of charges associated with SEEG and SDG monitoring at a single institution.

METHODS

The authors performed a retrospective case series analysis of pediatric patients with similar characteristics in terms of age, sex, seizure etiology, and epilepsy treatment strategy who underwent SEEG or SDG monitoring and subsequent craniotomy for resection of epileptogenic focus at St. Louis Children Hospital, St. Louis, Missouri, between 2013 and 2020. Financial data, including hospital charges, supplies, and professional fees (i.e., those related to anesthesia, neurology, neurosurgery, and critical care), were adjusted for inflation to 2020 US dollars.

RESULTS

The authors identified 18 patients (9 underwent SEEG and 9 underwent SDG) with similar characteristics in terms of age (mean [range] 13.6 [1.9–21.8] years for SDG patients vs 11.9 [2.4–19.6] years for SEEG patients, p = 0.607), sex (4 females underwent SDG vs 6 females underwent SEEG, p = 0.637), and presence of lesion (5 patients with a lesion underwent SDG vs 8 underwent SEEG, p = 0.294). All patients underwent subsequent craniotomy for resection of epileptogenic focus. SEEG patients were more likely to have a history of status epilepticus (p = 0.029). Across 1 hospitalization for each SDG patient and 2 hospitalizations for each SEEG patient, SEEG patients had a significantly shorter mean operating room time (288 vs 356 minutes, p = 0.015), mean length of stay in the ICU (1.0 vs 2.1 days, p < 0.001), and tended to have a shorter overall length of stay in the hospital (8.4 vs 10.6 days, p = 0.086). Both groups underwent invasive monitoring for similar lengths of time (5.2 days for SEEG patients vs 6.4 days for SDG patients, p = 0.257). Time to treatment from the initial invasive monitoring evaluation was significantly longer in SEEG patients (64.6 vs 6.4 days, p < 0.001). Neither group underwent readmission within the first 30 days after hospital discharge. Seizure outcomes and complication rates were similar. After adjustment for inflation, the average total perioperative charges were $104,442 for SDG and $106,291 for SEEG (p = 0.800).

CONCLUSIONS

Even though 2 hospitalizations were required for SEEG and 1 hospitalization was required for SDG monitoring, patients who underwent SEEG had a significantly shorter average length of stay in the ICU and operating room time. Surgical morbidity and outcomes were similar. Total perioperative charges for invasive monitoring and resection were approximately 2% higher for SEEG patients when corrected for inflation, but this difference was not statistically significant.

ABBREVIATIONS

EMU = epilepsy-monitoring unit; MRE = medically refractory epilepsy; OR = operating room; SDG = subdural grid; SEEG = stereoelectroencephalography.

OBJECTIVE

Use of invasive stereoelectroencephalography (SEEG) has gained traction recently. However, scant research has investigated the costs and resource utilization of SEEG compared with subdural grid (SDG)–based techniques in pediatric patients. Here, the authors have presented a retrospective analysis of charges associated with SEEG and SDG monitoring at a single institution.

METHODS

The authors performed a retrospective case series analysis of pediatric patients with similar characteristics in terms of age, sex, seizure etiology, and epilepsy treatment strategy who underwent SEEG or SDG monitoring and subsequent craniotomy for resection of epileptogenic focus at St. Louis Children Hospital, St. Louis, Missouri, between 2013 and 2020. Financial data, including hospital charges, supplies, and professional fees (i.e., those related to anesthesia, neurology, neurosurgery, and critical care), were adjusted for inflation to 2020 US dollars.

RESULTS

The authors identified 18 patients (9 underwent SEEG and 9 underwent SDG) with similar characteristics in terms of age (mean [range] 13.6 [1.9–21.8] years for SDG patients vs 11.9 [2.4–19.6] years for SEEG patients, p = 0.607), sex (4 females underwent SDG vs 6 females underwent SEEG, p = 0.637), and presence of lesion (5 patients with a lesion underwent SDG vs 8 underwent SEEG, p = 0.294). All patients underwent subsequent craniotomy for resection of epileptogenic focus. SEEG patients were more likely to have a history of status epilepticus (p = 0.029). Across 1 hospitalization for each SDG patient and 2 hospitalizations for each SEEG patient, SEEG patients had a significantly shorter mean operating room time (288 vs 356 minutes, p = 0.015), mean length of stay in the ICU (1.0 vs 2.1 days, p < 0.001), and tended to have a shorter overall length of stay in the hospital (8.4 vs 10.6 days, p = 0.086). Both groups underwent invasive monitoring for similar lengths of time (5.2 days for SEEG patients vs 6.4 days for SDG patients, p = 0.257). Time to treatment from the initial invasive monitoring evaluation was significantly longer in SEEG patients (64.6 vs 6.4 days, p < 0.001). Neither group underwent readmission within the first 30 days after hospital discharge. Seizure outcomes and complication rates were similar. After adjustment for inflation, the average total perioperative charges were $104,442 for SDG and $106,291 for SEEG (p = 0.800).

CONCLUSIONS

Even though 2 hospitalizations were required for SEEG and 1 hospitalization was required for SDG monitoring, patients who underwent SEEG had a significantly shorter average length of stay in the ICU and operating room time. Surgical morbidity and outcomes were similar. Total perioperative charges for invasive monitoring and resection were approximately 2% higher for SEEG patients when corrected for inflation, but this difference was not statistically significant.

In Brief

Invasive stereoelectroencephalography (SEEG) is increasingly utilized over subdural grid (SDG)—based techniques. However, the costs of these procedures are not well established, especially for pediatric patients. In a single-institution retrospective case series, the authors reported similar average total perioperative charges for SEEG ($106,291) and SDG ($104,442) when adjusted for inflation. This finding—along with the versatility, safety profile, and efficacy of SEEG—suggests that SEEG may be considered a first-line option for pediatric patients who require invasive monitoring.

Approximately 3.2–5.5 children per 1000 are diagnosed with epilepsy.1 As many as 30% of patients with epilepsy do not achieve long-term remission despite maximal medical management.2 A recent meta-analysis of more than 250 studies reported that epilepsy surgery is more effective than medical therapy for seizure control.3,4 A central tenet of surgical treatment of medically refractory epilepsy (MRE) is accurate identification of the epileptogenic focus for later resection.5 Presurgical evaluation includes interictal scalp EEG, structural imaging studies such as brain MRI, functional imaging studies such as interictal PET, magnetoencephalography, and neuropsychiatric tests.6 When noninvasive data are discordant or if the location of seizure onset is ambiguous, invasive monitoring with intracranial EEG may be indicated to determine the epileptogenic focus.7

Several technologies exist for invasive monitoring, including the traditional open procedure for placement of subdural grid (SDG) electrodes and minimally invasive techniques that use depth electrodes for stereoelectroencephalography (SEEG). The decision to choose a given technique over another for a particular patient is complex and involves consideration of multiple factors. SDG monitoring uses grids and strips to record cortical activity over a large surface area of the brain. SDG electrodes densely cover the cortex and are particularly beneficial for mapping motor and language functions, whereas SEEG is superior for targeting deeper regions of the brain. Although SDG monitoring has traditionally been used with fewer restrictions based on age, a minimum skull thickness is required for bolt placement for SEEG. With consideration of these limitations, bilateral coverage for SDG monitoring requires bilateral craniotomy or burr holes. SEEG, however, allows for targeting of bilateral regions for invasive recording and may be more suitable for patients who have undergone prior craniotomies.8,9

The complication rates reported in literature are higher for SDG monitoring. One meta-analysis of 2624 patients who underwent SEEG reported a hemorrhage rate of 1.0% and an infection rate of 0.8%.10 A meta-analysis of 2542 patients who underwent SDG monitoring reported a 2.3% rate of infections that included meningitis, abscess, and subdural empyema and a 3.0% rate of infections that included skin infections.11 Overall, SEEG had a complication rate of 1.3%, whereas 3.5% of patients required additional surgery after SDG implantation. The mortality and hardware malfunction rates reported in these meta-analyses were similar.

The published rates of seizure freedom/Engel class I outcome in patients who underwent subsequent epilepsy surgery after invasive monitoring were similar in recent large-cohort studies of SDG and SEEG.8 The rate of Engel class I outcome was 68% in a large cohort of patients that underwent epilepsy surgery after SEEG,12 which matched that of other large cohorts that underwent epilepsy surgery after SDG.13,14

In recent years, SEEG has risen in popularity in Europe and North America.15 Although recent studies have reported the surgical considerations, complication rates, and outcomes of SEEG and SDG, few have published cost comparisons between epilepsy surgery utilizing SDG monitoring and those using SEEG as invasive monitoring strategies, specifically in pediatric patients.1619 The primary aim of this study was to compare the inflation-adjusted costs of SDG with those of SEEG for invasive monitoring of pediatric patients with MRE, all of whom underwent subsequent resection. We also reported outcomes, including seizure freedom, readmission, and complication rates and hospital length of stay.

Methods

Study Design

All aspects of this study were approved by the IRB of the Washington University School of Medicine in St. Louis, Missouri. We performed a retrospective case series analysis of patients with MRE who were treated with invasive monitoring and epilepsy surgery at St. Louis Children’s Hospital between 2013 and 2020 by the senior author (M.D.S.).

Patient Selection and Data Collection

We identified all patients who underwent invasive SDG monitoring and SEEG for identification of epileptogenic foci by searching medical records for Current Procedural Terminology codes 61533 and 61760, respectively. A retrospective chart review was performed to obtain patient demographic characteristics, including sex, age at seizure onset, age at SDG/SEEG, epilepsy etiology (described as lesional or nonlesional), mean number of seizures per week prior to SDG/SEEG, number of antiepileptic drugs, history of status epilepticus, type of invasive monitoring surgery performed (SDG or SEEG), type of epilepsy surgery performed (craniotomy for resection of epileptogenic focus, laser ablation of epileptogenic focus, and vagus nerve stimulator placement), operating room (OR) times (time from when the patient entered the OR to when the patient left the OR) for only the invasive monitoring procedures (i.e., not including resection), hospital length of stay (including ICU stay), follow-up duration, Engel class, 30-day readmission, and surgical complications within 30 days of any surgery.

Lesional or nonlesional epilepsy was defined as presence or absence, respectively, of a structural abnormality on epilepsy-dedicated brain MRI, as determined with a formal neuroradiology evaluation. The OR times for the SDG group included only implantation surgery, whereas the OR times for the SEEG group were the sum of the OR times for SEEG implantation and SEEG removal (i.e., 2 surgical procedures). Professional fees billed by the departments of neurosurgery, neurology, anesthesia, and critical care, as well as hospital charges, were obtained from the billing department. All costs were adjusted for inflation to September 2020 by using the Consumer Price Index Inflation Calculator from the US Bureau of Labor Statistics and the month and year of hospital discharge.20 Patients were grouped according to type of invasive monitoring surgery, and all patients underwent subsequent craniotomy for resection of epileptogenic focus. All clinical and financial data were captured from 1 hospitalization for each SDG patient and 2 hospitalizations for each SEEG patient.

Treatment Protocols

At our institution, patients who have undergone noninvasive tests, such as brain MRI, interictal PET, and video EEG, and have discordant data requiring further investigation are evaluated by a multidisciplinary team, and then candidacy for invasive EEG recording is determined. The typical workflows for SDG monitoring and SEEG and subsequent epilepsy surgery are shown in Fig. 1.

FIG. 1.
FIG. 1.

Workflows for SDG monitoring and SEEG. Upper: Patients undergo 1 hospitalization for invasive monitoring with SDG and subsequent epilepsy surgery. After SDG placement, patients are admitted to the ICU where they undergo monitoring. After completion of monitoring, patients undergo surgery for removal of the SDG electrodes and resection of the epileptogenic focus. After surgery, patients recover in the ICU and then transition to a regular ward before being discharged home. Lower: Patients undergo 2 hospitalizations for SEEG placement/removal and subsequent epilepsy surgery. After SEEG electrode placement, patients are admitted to the EMU, which is a specialized ward where they undergo monitoring. After completion of monitoring, patients undergo surgery for SEEG electrode removal and are discharged home shortly after. Patients are admitted for a second hospitalization for resection of the epileptogenic focus. After surgery, patients recover in the ICU and then transition to a regular ward before being discharged home.

SDG electrodes are placed using an open technique, in which a craniotomy is performed and grid electrodes are placed on the cortex in the subdural space. This can be done in conjunction with intraoperative motor mapping. After confirmation of appropriate grid contact, the bone flap is replaced, the electrodes are tunneled away from the incision for later connection, and the incision is closed. After surgery, patients are admitted to the ICU. Patients are transferred to the ward with a specialized epilepsy-monitoring unit (EMU) on postoperative day 1 or 2. The neurology team weans the patient from antiepileptic medications, and the patient is monitored for clinical and electrographic seizure activity. After enough epileptiform activity has been recorded and interpretated, the patient undergoes a second craniotomy to remove the SDG electrodes and resect the epileptogenic focus. After this surgery, the patient is monitored overnight in the ICU and transferred to the ward where they work toward discharge.

SEEG electrodes are placed using a minimally invasive technique. Depth electrodes are placed individually using small incisions and twist drill holes in order to reach the preplanned targets with ROSA robotic navigation (Zimmer Biomet). The neurophysiology team then intraoperatively confirms that each electrode has the appropriate signal. After surgery, head CT is obtained to rule out intracranial hemorrhage and confirm accurate electrode placement. Patients are then transferred directly to the EMU, where the neurology team weans the patient from medications while monitoring for seizure activity. After enough data have been collected, the patient is brought back to the OR for SEEG electrode removal and is discharged home, usually later the same day, after an observation period. The patient is readmitted to undergo surgical treatment. After resection, the patient is admitted to the ICU for 1–2 days before transfer to the ward where they work toward discharge.

Both types of surgery require a specialized nonsurgical team in the OR. The team consists of neuroanesthesiologists familiar with intraoperative EEG recording, neurologists for interpretation and verification of the electrode contacts, and an EEG technician team for processing EEG readings. SEEG electrode placement may also require an additional team member who specializes in operating the robotic interface.

Statistical Analysis

Means, standard deviations, and ranges were calculated for patient and hospitalization characteristics, clinical outcomes, and costs, where appropriate. The Fisher’s exact test and 2-tailed Student t-test were used to calculate p values for continuous and categorical variables, as appropriate. In this study, p < 0.05 was used to indicate statistical significance.

Results

The initial search for all patients with MRE who underwent invasive monitoring at our institution between 2013 and 2020 yielded 44 patients. Ages ranged from 2 to 23 years at the time of surgery, and 25 females were included. Twenty-three patients were excluded because they did not undergo resection and instead underwent laser ablation (n = 6), neurostimulator placement (n = 1), or vagus nerve stimulator placement (n = 9) or did not undergo any further surgery (n = 7). One patient underwent both SDG monitoring and SEEG in the same surgery and was excluded. Financial information regarding the hospitalizations of 2 patients could not be obtained.

A total of 9 SDG and 9 SEEG patients were included in the analysis (Table 1). There were 4 females in the SDG group and 6 in the SEEG group (p = 0.637). The mean age at seizure onset was similar between groups (4.8 years for SDG patients vs 5.1 years for SEEG patients, p = 0.915), and the mean age at surgery was also similar between groups (13.6 years for SDG vs 11.9 years for SEEG, p = 0.607). The mean duration of epilepsy prior to invasive monitoring was similar between groups (101.7 months for SDG vs 77.4 months for SEEG, p = 0.503). Lesions identifiable on MRI were found in 5 patients who underwent SDG and 8 patients who underwent SEEG (p = 0.294). The mean number of weekly seizures was similar between groups (5.6 for SDG patients vs 9.0 for SEEG patients, p = 0.415). The mean number of antiepileptic drugs was also similar between groups (2.4 for SDG patients vs 2.3 for SEEG patients, p = 0.747). Five patients who underwent SEEG had histories of status epilepticus, whereas no patients who underwent SDG had this history (p = 0.029). All patients underwent subsequent craniotomy for resection of epileptogenic focus.

TABLE 1.

Baseline patient characteristics

CharacteristicSDGSEEGp Value
Patients99
Female sex4 (44.4)6 (66.7)0.637
Age, yrs
 Seizure onset4.8 (0.3–13)5.1 (0.5–16)0.915
 Surgery13.6 (1.9–21.8)11.9 (2.4–19.6)0.607
Mean epilepsy duration prior to SDG/SEEG, mos101.777.40.503
Presence of lesion5 (55.6)8 (88.9)0.294
Mean baseline seizure frequency, no./wk5.69.00.415
Mean antiepileptic drugs prior to surgery2.42.30.747
History of status epilepticus050.029
Craniotomy for resection of epileptogenic focus99

Values are shown as number, number (%), or mean (range) unless indicated otherwise. Boldface type indicates statistical significance (p < 0.05).

Across 1 hospitalization for each SDG patient and 2 hospitalizations for each SEEG patient, the average stay in the ICU was 2.1 days for the SDG group compared with 1 day for the SEEG group (p < 0.001) (Table 2). The mean OR time for invasive monitoring surgical procedures was shorter in the SEEG group (288 vs 356 minutes for SDG, p = 0.015), even though the SEEG group underwent 2 surgical procedures. The mean invasive monitoring times were similar between groups (6.4 days for SDG vs 5.2 days for SEEG, p = 0.257). The mean total hospital length of stay of the SDG patients (10.6 days) was longer than that of the SEEG patients (8.4 days), but this difference did not reach statistical significance (p = 0.086). Patients underwent the subsequent epilepsy surgery for resection of the epileptogenic focus within an average of 6.4 days after SDG placement and 64.6 days after SEEG electrode placement (p < 0.001). This expected finding was related to differences in workflow, in which SDG patients underwent 1 hospitalization for monitoring and treatment, whereas SEEG patients underwent 1 hospitalization for monitoring and a second hospitalization for elective resection.

TABLE 2.

Hospitalizations and clinical outcomes

OutcomeSDGSEEGp Value
OR time, mins356 ± 60*288 ± 430.015
ICU stay, days2.1 (2–3)1.0 (1–1)<0.001
Invasive monitoring time, days6.4 (3–9)5.2 (3–9)0.257
Hospital length of stay, days10.6 (8–13)8.4 (2–9)0.086
30-day readmission00
Time to epilepsy surgery, days6.4 (3–9)64.6 (30–112)<0.001
Engel class I outcome at follow-up360.347
Length of follow-up, yrs3.1 (0.6–5.4)1.2 (0.1–3.1)
Complications2 (22.2)0 (0)0.471

Values are shown as number, number (percent), mean ± SD, or mean (range) unless indicated otherwise. Boldface type indicates statistical significance (p < 0.05).

Time from when the patient entered the OR to when the patient left the OR for SDG electrode placement surgery.

Total time from when the patient entered the OR to when the patient left the OR for SEEG electrode placement and removal.

Seizure outcomes at follow-up were similar between the groups: 3 patients who underwent SDG had Engel class I seizure freedom versus 6 patients who underwent SEEG (p = 0.347). The length of follow-up was longer in the SDG group. There were 2 complications in the SDG group, which consisted of transient contralateral hemiparesis that resolved with steroid tapering and a superficial skin infection that was successfully treated with oral antibiotics in the outpatient setting. There were no complications in the SEEG group.

We noticed a shift in practice patterns over time—with 6 of 9 SDG patients treated before 2016 and all 9 SEEG patients treated in or after 2016—and performed an inflation-adjusted cost analysis with September 2020 as the reference point (Table 3 and Fig. 2). Based on Consumer Price Index data from the US Bureau of Labor Statistics, the average inflation rate between September 2018 and September 2020 was 3.1%. All costs were adjusted on the basis of this rate in order to reflect the purchasing power of the US dollar in September 2020. This number was used to adjust each charge or fee value. Hospital charges were similar between groups (mean $64,002 for SDG monitoring vs $66,263 for SEEG, p = 0.704). On average, the SEEG group had higher neurosurgery fees than the SDG group ($18,752 vs $16,171, p = 0.003), whereas the SDG group had higher neurology fees than the SEEG group ($12,425 vs $8745, p = 0.034). Although anesthesia fees tended to be higher in the SEEG group, this difference did not reach statistical significance. Critical care fees were higher in the SDG group than the SEEG group ($2845 vs $1843, p < 0.001). Overall, the mean total perioperative costs were similar between the groups ($104,442 for SDG vs $106,291 for SEEG, p = 0.800), or approximately $1849 (1.8%) higher in the SEEG group.

TABLE 3.

Inflation-adjusted cost comparison

Periop ChargesSDGSEEGp Value
Hospital charges & supplies$64,002 ± $11,092$66,263 ± $13,5860.704
Neurosurgery fees$16,171 ± $1576$18,752 ± $15140.003
Neurology fees$12,425 ± $3240$8745 ± $34730.034
Anesthesia fees$8999 ± $1935$10,687 ± $19180.081
Critical care fees$2845 ± $388$1843 ± $116<0.001
Total charges$104,442 ± $13,238$106,291 ± $16,9080.800

Values are shown as mean ± SD unless indicated otherwise. Boldface type indicates statistical significance (p < 0.05).

FIG. 2.
FIG. 2.

Cost comparison between SDG monitoring and SEEG. All costs were adjusted for inflation to 2020 US dollars.

Discussion

In this single-institution case series of pediatric patients with MRE who underwent invasive monitoring with SDG or SEEG and were matched for treatment strategy (subsequent resection), we found that the mean ICU stay was shorter in the SEEG group, the mean time to epilepsy surgery was shorter in the SDG group, and the seizure outcome and complication rates were similar between groups. The mean OR time for invasive monitoring was shorter in the SEEG group than the SDG group, even though SEEG patients underwent 2 separate surgical procedures. Although the correlative etiology was unrecognized and could have been the result of the small sample size, we observed that SEEG patients were more likely to have a history of status epilepticus. Neurosurgery fees were higher in the SEEG group, even though this group had shorter OR times; this finding was likely secondary to the second procedure (electrode removal), in addition to electrode placement. Neurology fees were higher in the SDG group; this finding may be due to the greater number of hours billed for SDG placement, which had a greater mean OR time than SEEG placement. Critical care fees were higher in the SDG group and were proportional to the increased length of ICU stay for these patients. However, overall perioperative charges were similar between groups.

Newer recording techniques such as SEEG have evolved over recent decades to integrate modern structural imaging and electrophysiology technologies, aid localization of epileptogenic tissue, and inform resection strategies.1618,21 Complication rates, seizure freedom outcomes, and opiate usage have been widely reported.8,10,11,13,14 Recent evidence from a large retrospective study found that, despite being less likely to have lesions on MRI, patients who underwent SEEG experienced less pain, had fewer complications, and had greater seizure freedom outcomes than patients who underwent SDG monitoring for resection or ablation.22 Thus, based on the surgical and seizure outcomes alone, SEEG may be at least a noninferior strategy for invasive monitoring in comparison with SDG.

The results of our study expand upon those of a recent single-institution cost analysis of pediatric patients who underwent SEEG or SDG monitoring from 2014 to 2017.19 Our results were similar in that both SDG monitoring and SEEG provided comparable seizure freedom outcomes and were associated with similar overall costs. The previous study also reported that patients who underwent SEEG had decreased narcotic usage and operative times. The finding of reduced operative time in the SEEG group was also corroborated by our study. Our group previously reported operative time efficiency for the use of robotics for SEEG electrode placement.23 However, our current study included professional fees and adjusted all financial data for inflation, which allowed for standardized cost comparisons without the influence of economic forces; this allowed us to confirm that the overall costs of both procedures were similar. We reported that SEEG patients waited significantly longer to undergo resection of their epileptogenic focus than the SDG group, which may be another consideration when deciding between SDG and SEEG. This is secondary to the workflow differences between SEEG and SDG at our institution. SEEG patients were discharged home after removal of SEEG electrodes, and they returned in a delayed fashion after the neurology team thoroughly reviewed the SEEG recordings and cases were discussed again in the joint epilepsy conference. Our study is unique because we reported the data of patients who all ultimately underwent resection and found comparable total costs between groups. These findings suggest that SDG and SEEG have similar costs based on the matched comparison of treatment strategies.

The reported advantages of SEEG include the capabilities to provide bilateral coverage, target deep epileptogenic tissue, reduce opiate usage, shorten operative times, lower complication rates, and provide noninferior rates of seizure freedom. The competitive costs of SEEG make it an attractive first-line consideration for invasive monitoring of pediatric patients with MRE and discordant noninvasive data. This study was limited by its retrospective nature; however, all end points of interest were captured by our review of the medical charts and billing information. Our sample size was small—9 patients in each group—but the groups were matched according to seizure etiology and epilepsy treatment strategy in order to minimize confounding variables in our cost analysis. Because this and other similar studies have reported only single-institution experiences, future studies on this subject should include data from multiple institutions in order to provide more generalizable conclusions based on surgical outcomes, seizure freedom, and inflation-adjusted cost efficiency.

Conclusions

Pediatric patients with MRE who underwent SEEG and subsequent resection as the epilepsy treatment strategy had similar complication rates and similarly favorable seizure outcomes compared with patients who underwent SDG, but SEEG patients had shorter ICU stays. The total perioperative costs of these procedures were similar after adjustment for inflation.

Acknowledgments

We acknowledge the team efforts of the Department of Neurology and Department of Neurological Surgery at St. Louis Children’s Hospital for diagnosing and treating patients with medically refractory epilepsy.

Disclosures

Dr. Smyth is a consultant for Zimmer Biomet ROSA.

Author Contributions

Conception and design: Salehi, Smyth. Acquisition of data: Yang, Salehi. Analysis and interpretation of data: Yang, Salehi. Drafting the article: all authors. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Yang. Statistical analysis: Yang, Salehi. Administrative/technical/material support: Smyth. Study supervision: Salehi, Smyth.

Supplemental Information

Previous Presentations

This study was presented virtually at the Annual Meeting of the AANS/CNS Section on Pediatric Neurological Surgery, December 2–4, 2020.

References

  • 1

    Camfield P, Camfield C. Incidence, prevalence and aetiology of seizures and epilepsy in children. Epileptic Disord. 2015;17(2):117123.

  • 2

    Kwan P, Brodie MJ. Early identification of refractory epilepsy. N Engl J Med. 2000;342(5):314319.

  • 3

    Widjaja E, Jain P, Demoe L, Guttmann A, Tomlinson G, Sander B. Seizure outcome of pediatric epilepsy surgery: Systematic review and meta-analyses. Neurology. 2020;94(7):311321.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Wiebe S, Blume WT, Girvin JP, Eliasziw M. A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med. 2001;345(5):311318.

  • 5

    Cardinale F, Cossu M, Castana L, et al. Stereoelectroencephalography: surgical methodology, safety, and stereotactic application accuracy in 500 procedures. Neurosurgery. 2013;72(3):353366.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Cross JH, Jayakar P, Nordli D, et al. Proposed criteria for referral and evaluation of children for epilepsy surgery: recommendations of the Subcommission for Pediatric Epilepsy Surgery. Epilepsia. 2006;47(6):952959.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Spencer SS, Spencer DD, Williamson PD, Mattson RH. The localizing value of depth electroencephalography in 32 patients with refractory epilepsy. Ann Neurol. 1982;12(3):248253.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Katz JS, Abel TJ. Stereoelectroencephalography versus subdural electrodes for localization of the epileptogenic zone: what is the evidence?. Neurotherapeutics. 2019;16(1):5966.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Vadera S, Jehi L, Gonzalez-Martinez J, Bingaman W. Safety and long-term seizure-free outcomes of subdural grid placement in patients with a history of prior craniotomy. Neurosurgery. 2013;73(3):395400.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Mullin JP, Shriver M, Alomar S, et al. Is SEEG safe? A systematic review and meta-analysis of stereo-electroencephalography-related complications. Epilepsia. 2016;57(3):386401.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11

    Arya R, Mangano FT, Horn PS, Holland KD, Rose DF, Glauser TA. Adverse events related to extraoperative invasive EEG monitoring with subdural grid electrodes: a systematic review and meta-analysis. Epilepsia. 2013;54(5):828839.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Serletis D, Bulacio J, Bingaman W, Najm I, González-Martínez J. The stereotactic approach for mapping epileptic networks: a prospective study of 200 patients. J Neurosurg. 2014;121(5):12391246.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Mullin JP, Sexton D, Al-Omar S, Bingaman W, Gonzalez-Martinez J. Outcomes of subdural grid electrode monitoring in the stereoelectroencephalography era. World Neurosurg. 2016;89:255258.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Bekelis K, Radwan TA, Desai A, et al. Subdural interhemispheric grid electrodes for intracranial epilepsy monitoring: feasibility, safety, and utility: clinical article. J Neurosurg. 2012;117(6):11821188.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    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. 2018;53:132134.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Joswig H, Lau JC, Abdallat M, et al. Stereoelectroencephalography versus subdural strip electrode implantations: feasibility, complications, and outcomes in 500 intracranial monitoring cases for drug-resistant epilepsy. Neurosurgery. 2020;87(1):E23E30.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Skoch J, Adelson PD, Bhatia S, et al. Subdural grid and depth electrode monitoring in pediatric patients. Epilepsia. 2017;58(suppl 1):5665.

  • 18

    Wang YC, Grewal SS, Goyal A, et al. Comparison of narcotic pain control between stereotactic electrocorticography and subdural grid implantation. Epilepsy Behav. 2020;103(Pt A):106843.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Kim LH, Parker JJ, Ho AL, et al. Postoperative outcomes following pediatric intracranial electrode monitoring: a case for stereoelectroencephalography (SEEG). Epilepsy Behav. 2020;104(Pt A):106905.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    CPI Inflation Calculator. US Bureau of Labor Statistics. Accessed January 10, 2022. https://www.bls.gov/data/inflation_calculator.htm

  • 21

    Reif PS, Strzelczyk A, Rosenow F. The history of invasive EEG evaluation in epilepsy patients. Seizure. 2016;41:191195.

  • 22

    Tandon N, Tong BA, Friedman ER, et al. Analysis of morbidity and outcomes associated with use of subdural grids vs stereoelectroencephalography in patients with intractable epilepsy. JAMA Neurol. 2019;76(6):672681.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Miller BA, Salehi A, Limbrick DD Jr, Smyth MD. Applications of a robotic stereotactic arm for pediatric epilepsy and neurooncology surgery. J Neurosurg Pediatr. 2017;20(4):364370.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation

Diagram from Behbahani et al. (pp 488–496).

  • View in gallery

    Workflows for SDG monitoring and SEEG. Upper: Patients undergo 1 hospitalization for invasive monitoring with SDG and subsequent epilepsy surgery. After SDG placement, patients are admitted to the ICU where they undergo monitoring. After completion of monitoring, patients undergo surgery for removal of the SDG electrodes and resection of the epileptogenic focus. After surgery, patients recover in the ICU and then transition to a regular ward before being discharged home. Lower: Patients undergo 2 hospitalizations for SEEG placement/removal and subsequent epilepsy surgery. After SEEG electrode placement, patients are admitted to the EMU, which is a specialized ward where they undergo monitoring. After completion of monitoring, patients undergo surgery for SEEG electrode removal and are discharged home shortly after. Patients are admitted for a second hospitalization for resection of the epileptogenic focus. After surgery, patients recover in the ICU and then transition to a regular ward before being discharged home.

  • View in gallery

    Cost comparison between SDG monitoring and SEEG. All costs were adjusted for inflation to 2020 US dollars.

  • 1

    Camfield P, Camfield C. Incidence, prevalence and aetiology of seizures and epilepsy in children. Epileptic Disord. 2015;17(2):117123.

  • 2

    Kwan P, Brodie MJ. Early identification of refractory epilepsy. N Engl J Med. 2000;342(5):314319.

  • 3

    Widjaja E, Jain P, Demoe L, Guttmann A, Tomlinson G, Sander B. Seizure outcome of pediatric epilepsy surgery: Systematic review and meta-analyses. Neurology. 2020;94(7):311321.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Wiebe S, Blume WT, Girvin JP, Eliasziw M. A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med. 2001;345(5):311318.

  • 5

    Cardinale F, Cossu M, Castana L, et al. Stereoelectroencephalography: surgical methodology, safety, and stereotactic application accuracy in 500 procedures. Neurosurgery. 2013;72(3):353366.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Cross JH, Jayakar P, Nordli D, et al. Proposed criteria for referral and evaluation of children for epilepsy surgery: recommendations of the Subcommission for Pediatric Epilepsy Surgery. Epilepsia. 2006;47(6):952959.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Spencer SS, Spencer DD, Williamson PD, Mattson RH. The localizing value of depth electroencephalography in 32 patients with refractory epilepsy. Ann Neurol. 1982;12(3):248253.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Katz JS, Abel TJ. Stereoelectroencephalography versus subdural electrodes for localization of the epileptogenic zone: what is the evidence?. Neurotherapeutics. 2019;16(1):5966.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Vadera S, Jehi L, Gonzalez-Martinez J, Bingaman W. Safety and long-term seizure-free outcomes of subdural grid placement in patients with a history of prior craniotomy. Neurosurgery. 2013;73(3):395400.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Mullin JP, Shriver M, Alomar S, et al. Is SEEG safe? A systematic review and meta-analysis of stereo-electroencephalography-related complications. Epilepsia. 2016;57(3):386401.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11

    Arya R, Mangano FT, Horn PS, Holland KD, Rose DF, Glauser TA. Adverse events related to extraoperative invasive EEG monitoring with subdural grid electrodes: a systematic review and meta-analysis. Epilepsia. 2013;54(5):828839.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Serletis D, Bulacio J, Bingaman W, Najm I, González-Martínez J. The stereotactic approach for mapping epileptic networks: a prospective study of 200 patients. J Neurosurg. 2014;121(5):12391246.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Mullin JP, Sexton D, Al-Omar S, Bingaman W, Gonzalez-Martinez J. Outcomes of subdural grid electrode monitoring in the stereoelectroencephalography era. World Neurosurg. 2016;89:255258.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Bekelis K, Radwan TA, Desai A, et al. Subdural interhemispheric grid electrodes for intracranial epilepsy monitoring: feasibility, safety, and utility: clinical article. J Neurosurg. 2012;117(6):11821188.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    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. 2018;53:132134.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Joswig H, Lau JC, Abdallat M, et al. Stereoelectroencephalography versus subdural strip electrode implantations: feasibility, complications, and outcomes in 500 intracranial monitoring cases for drug-resistant epilepsy. Neurosurgery. 2020;87(1):E23E30.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Skoch J, Adelson PD, Bhatia S, et al. Subdural grid and depth electrode monitoring in pediatric patients. Epilepsia. 2017;58(suppl 1):5665.

  • 18

    Wang YC, Grewal SS, Goyal A, et al. Comparison of narcotic pain control between stereotactic electrocorticography and subdural grid implantation. Epilepsy Behav. 2020;103(Pt A):106843.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Kim LH, Parker JJ, Ho AL, et al. Postoperative outcomes following pediatric intracranial electrode monitoring: a case for stereoelectroencephalography (SEEG). Epilepsy Behav. 2020;104(Pt A):106905.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    CPI Inflation Calculator. US Bureau of Labor Statistics. Accessed January 10, 2022. https://www.bls.gov/data/inflation_calculator.htm

  • 21

    Reif PS, Strzelczyk A, Rosenow F. The history of invasive EEG evaluation in epilepsy patients. Seizure. 2016;41:191195.

  • 22

    Tandon N, Tong BA, Friedman ER, et al. Analysis of morbidity and outcomes associated with use of subdural grids vs stereoelectroencephalography in patients with intractable epilepsy. JAMA Neurol. 2019;76(6):672681.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Miller BA, Salehi A, Limbrick DD Jr, Smyth MD. Applications of a robotic stereotactic arm for pediatric epilepsy and neurooncology surgery. J Neurosurg Pediatr. 2017;20(4):364370.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 123 123 123
PDF Downloads 85 85 85
EPUB Downloads 0 0 0