Stereoelectroencephalography electrode implantation accuracy

Stereoelectroencephalography electrode implantation accuracy

The accuracy of stereoelectroencephalography electrode implantation is an important factor in maximizing its safety.

The implantation of deep brain electrodes for SEEG by using intraoperative CT O Arm® and the Vertek® articulated passive arm is a safe and effective technique with adequate accuracy 1).

Robot-assisted stereoelectroencephalography electrode placement is highly accurate and is significantly more accurate than optical frameless neuronavigation (ON). Larger safety margins away from vascular structures should be used when placing deep electrodes in young children and for trajectories that pass through thicker soft tissues such as the temporal region 2).

Patient-customized platforms are comparable in terms of safety, accuracy, and simplicity of use to the existing robotic devices for implantation of depth electrodes 3).

Rodionov et al., established a quality assurance (QA) process to aid advances in implantation accuracy.

The accuracy of three consecutive modifications of a frameless implantation technique was quantified in three cohorts comprising 22, 8, and 23 consecutive patients. The modifications of the technique aimed to increase accuracy of the bolt placement.

The lateral shift of the axis of the implanted bolt at the level of the planned entry point was reduced from a mean of 3.0 ± 1.6 mm to 1.4 ± 0.8 mm. The lateral shift of the axis of the implanted bolt at the level of the planned target point was reduced from a mean of 3.8 ± 2.5 mm to 1.6 ± 0.9 mm.

This QA framework helped to isolate and quantify the factors introducing inaccuracy in SEEG implantation, and to monitor ongoing accuracy and the effect of technique modifications 4).

Granados et al., presented a method robust to electrode bending that can accurately segment contact positions and bolt orientation. The techniques presented will allow further characterisation of bending within different brain regions 5).



Narváez-Martínez Y, García S, Roldán P, Torales J, Rumià J. [Stereoelectroencephalography by using O-Arm(®) and Vertek(®) passive articulated arm: Technical note and experience of an epilepsy referral centre]. Neurocirugia (Astur). 2016 Nov – Dec;27(6):277-284. doi: 10.1016/j.neucir.2016.05.002. Spanish. PubMed PMID: 27345416.

Sharma JD, Seunarine KK, Tahir MZ, Tisdall MM. Accuracy of robot-assisted versus optical frameless navigated stereoelectroencephalography electrode placement in children. J Neurosurg Pediatr. 2019 Jan 4;23(3):297-302. doi: 10.3171/2018.10.PEDS18227. PubMed PMID: 30611155.

Yu H, Pistol C, Franklin R, Barborica A. Clinical Accuracy of Customized Stereotactic Fixtures for Stereoelectroencephalography. World Neurosurg. 2018 Jan;109:82-88. doi: 10.1016/j.wneu.2017.09.089. Epub 2017 Sep 22. PubMed PMID: 28951181.

Rodionov R, O’Keeffe A, Nowell M, Rizzi M, Vakharia VN, Wykes V, Eriksson SH, Miserocchi A, McEvoy AW, Ourselin S, Duncan JS. Increasing the accuracy of 3D EEG implantations. J Neurosurg. 2019 May 17:1-8. doi: 10.3171/2019.2.JNS183313. [Epub ahead of print] PubMed PMID: 31100733.

Granados A, Vakharia V, Rodionov R, Schweiger M, Vos SB, O’Keeffe AG, Li K, Wu C, Miserocchi A, McEvoy AW, Clarkson MJ, Duncan JS, Sparks R, Ourselin S. Automatic segmentation of stereoelectroencephalography (SEEG) electrodes post-implantation considering bending. Int J Comput Assist Radiol Surg. 2018 May 7. doi: 10.1007/s11548-018-1740-8. [Epub ahead of print] PubMed PMID: 29736800.

Delayed post-operative haemorrhage after carmustine wafer implantation

Implantation of carmustine wafers has been associated with increased operative site complications in some series, but post-operative haematoma is not routinely reported.
A retrospective audit of surgical site haematoma after tumour resection and insertion of carmustine wafers in two neurosurgical units in the UK (University Hospital of North Staffordshire, Stoke-on-Trent, March 2003 – July 2012; Wessex Neurological Centre, Southampton, October 2005 – January 2013) in 181 operations of 177 patients showed 8 (4.4%) patients. All presented in a delayed fashion on or after Day 2 post-operatively. In contrast, acute operative site haematoma was present in 4/491 (0.81%) of patients who underwent resection without gliadel wafer insertion.
In contrast to the expected timing of bleeding following intracranial tumour resection, all carmustine wafer patients who experienced haemorrhage presented in a delayed fashion on or after Day 2 post-operatively. The causative factors for universally delayed post-operative haematoma after carmustine wafer insertion are unclear and further studies are required to characterize this phenomenon ((Shah RS, Homapour B, Casselden E, Barr JG, Grundy PL, Brydon HL. Delayed
post-operative haemorrhage after carmustine wafer implantation: a case series
from two UK centres. Br J Neurosurg. 2013 Dec 9. [Epub ahead of print] PubMed
PMID: 24313309.))
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