Neuronavigation-guided Frameless Stereoelectroencephalography (SEEG)

Abstract

Stereoelectroencephalography (SEEG) is an invasive surgical procedure used to identify epileptogenic zones. The combination of both subdural grids and depth electrodes (DEs) is currently used for invasive intracranial monitoring in many epilepsy centers. To perform DE implantation, some centers use frame-based stereotactic techniques and others use stereotactic robotic techniques. However, not all epilepsy centers have access to these tools. We hypothesized that DE implantation using a neuronavigation system can be utilized for subsequent epilepsy surgery. Between April 2016 and April 2017, we performed invasive monitoring for 26 patients. Among these, 17 patients (8 females, 9 males; mean age, 21.2 years; range, 3–51 years) underwent DE implantation. We divided patients into three groups: Group 1 (7 patients), a free-hand implantation group; Group 2 (7 patients), a frameless stereotactic implantation group; and Group 3 (3 patients), a computed tomography (CT)-guided auto image registration system with the stereotactic implantation group. Group 3 showed the closest distance from planned target to DE tip, followed by Group 2. Fourteen of the 17 patients underwent subsequent epilepsy surgery referring to the results of DE studies. DE placement using a neuronavigation system without stereotactic robotic equipment or frame-based stereotactic techniques can be utilized for subsequent epilepsy surgery.

VarioGuide® frameless neuronavigation-guided stereoelectroencephalography in adult epilepsy patients: technique, accuracy and clinical experience

“…Our measured mean TP deviation was 2.7 ± 2.0 mm. With regard to the existing literature, our accuracy results were worse than those achieved by frame-based/robotic-assisted approaches [ 13 , 14 , 20 , 22 – 27 , 34 ] Most groups utilising those implantation techniques report TP deviations in the range of 0.3–6.7 mm [ 14 , 20 , 22 , 24 , 26 , 34 , 36 ]. In-depth analysis of our data revealed that one patient (Pat.…”

“…Stereoelectroencephalography techniques are categorised into three distinct technical approaches: frame-based, robot-assisted and frameless surgery (Suppl. Table 2 ) [ 1 , 2 , 4 , 5 , 7 , 9 , 10 , 12 – 20 , 24 – 29 , 31 – 33 , 37 , 38 , 40 – 43 , 45 – 47 , 49 – 54 , 58 , 59 , 65 – 67 ]. Superior accuracy is not only important to ensure diagnostic efficacy, but also correlates with surgical complications such as electrode malpositioning and haemorrhage [ 7 , 11 , 16 , 39 , 43 , 49 , 58 ].…”

“…The VarioGuide® (VG) system (BrainLab AG, Germany) is an already widely used and well-established tool to conduct frameless neuronavigation-guided intracranial biopsies with good accuracy [ 8 , 21 , 44 , 60 ]. Data in the context of frameless VG-SEEG are, however, still scarce and to the best of our knowledge, only three studies on VG-SEEG are available [ 9 , 24 , 59 ].…”

Nutritional Intervention Facilitates Food Intake after Epilepsy Surgery

“…Patients who fulfilled the following criteria were also excluded: (1) patients who received tube feeding; (2) patients who underwent depth electrode placement surgery through burr holes; (3) patients who underwent multiple SEs because the first SE did not cover an appropriate area such as the edge of the grid or a region outside the grid, and then they underwent second or third SEs; (4) patients who exhibited postoperative disturbance of consciousness due to status epilepticus, major complications such as massive subdural hematoma, severe meningitis, or other factors that prevented postoperative nutritional intervention and required prolonged infusion therapy; and (5) patients who were on a ketogenic diet including the classical ketogenic or modified Atkins diet. Patients who underwent burr hole surgery were excluded because this surgery is less invasive than open cranial electrode placement, and there could be differences in intracranial pressure [ 23 ]. Patients who underwent multiple SEs were excluded because we could not simply perform comparisons before and after the introduction of the nutritional intervention for any of these patients who exhibited postoperative disturbance of consciousness.…”

<p>Estimation of Risk Factors for Head Slippage Using a Head Clamp System. A Retrospective Study</p>

“…Spatial errors theoretically do not exist between these structures. 8 We applied this system without surface matching, using a touchless laser pointer for patient registration, and thus accurately measured head slippage.…”