ORIGINAL ARTICLE - FUNCTIONAL
Methodology, outcome, safety and in vivo accuracy in traditional
Lars E. van der Loo
Olaf E. M. G. Schijns
Albert J. Colon
G. Louis Wagner
Jim T. A. Dings
Pieter L. Kubben
Received: 3 April 2017 /Accepted: 31 May 2017 /Published online: 5 July 2017
The Author(s) 2017. This article is an open access publication
Background Stereoelectroencephalography (SEEG) is an
established diagnostic technique for the localization of the
epileptogenic zone in drug-resistant epilepsy. In vivo accuracy
of SEEG electrode positioning is of paramount importance
since higher accuracy may lead to more precise resective sur-
gery, better seizure outcome and reduction of complications.
Objective To describe experiences with the SEEG technique
in our comprehensive epilepsy center, to illustrate surgical
methodology, to evaluate in vivo application accuracy and to
consider the diagnostic yield of SEEG implantations.
Methods All patients who underwent SEEG implantations
between September 2008 and April 2016 were analyzed.
Planned electrode trajectories were compared with post-
implantation trajectories after fusion of pre- and postoperative
imaging. Quantitative analysis of deviation using Euclidean
distance and directional errors was performed. Explanatory
variables for electrode accuracy were analyzed using linear
regression modeling. The surgical methodology, procedure-
related complications and diagnostic yield were reported.
Results Seventy-six implantations were performed in 71 pa-
tients, and a total of 902 electrodes were implanted. Median
entry and target point deviations were 1.54 mm and 2.93 mm.
Several factors that predicted entry and target point accuracy
were identified. The rate of major complications was 2.6%.
SEEG led to surgical therapy of various modalities in 53 pa-
Conclusions This study demonstrated that entry and target
point localization errors can be predicted by linear regression
models, which can aid in identification of high-risk electrode
trajectories and further enhancement of accuracy. SEEG is a
reliable technique, as demonstrated by the high accuracy of
conventional frame-based implantation methodology and the
good diagnostic yield.
Approximately 20% to 40% of epilepsy patients have seizures
that are or become drug resistant [13, 23, 28, 36, 43, 63, 81]. In
a significant part of these patients, surgery is superior to
prolonged medical therapy [24, 84]. Successful surgery can
lead to seizure freedom or significant seizure reduction and
consequently lead to an improved quality of life and a lower
morbidity/mortality rate [49, 57, 84].
The concept of the epileptogenic zone (EZ) is important for
the presurgical approach in delineating the seizure focus and
network accurately, resulting in an optimal, patient-tailored
resection planning, which may lead to a better postoperative
outcome [55, 61, 62]. The epileptogenic zone is defined as the
Barea of cortex that is indispensable for the generation of ep-
ileptic seizures,^ and resection or disconnection of this zone is
necessary for seizure freedom or reduction [47, 62].
Frequently, noninvasive diagnostic tools are adequate for
the identification of the EZ. However, the number of highly
complex patients in whom invasive intracranial diagnostic
* Pieter L. Kubben
Department of Neurosurgery, Maastricht University Medical Center,
Maastricht, Limburg, The Netherlands
School of Mental Health and Neuroscience, Maastricht University
Medical Center, Maastricht, Limburg, The Netherlands
Academic Centre for Epileptology, Kempenhaeghe/Maastricht
University Medical Centre, Heeze/Maastricht, Limburg,
Acta Neurochir (2017) 159:1733–1746