BACKGROUND: Intracranial electrode monitoring is still required in epilepsy surgery; however, it is associated with significant morbidity. OBJECTIVE: To identify risk factors associated with complications during invasive intracranial EEG monitoring. MATERIALS AND METHODS: Retrospective study of all patients undergoing invasive monitoring at Westmead between 1988-2004. From detailed chart reviews, the following variables were recorded: duration of intracranial monitoring, the site of grid implantation, number of grids and electrodes, seizure frequency, postoperative complications and seizure outcome. RESULTS: Seventy-one patients (median age: 24 years) underwent subdural electrode implantation; 62% had extratemporal lobe epilepsy and 46% were non-lesional. Of the 58 monitored patients who had cortical resections, 45 had good seizure outcomes. Complications related to subdural electrode implantation included transient complications requiring no treatment (12.7%), transient complications requiring treatment (9.9%) and two deaths (2.8%). Specific complications included subdural haemorrhage, transient neurological deficit, infarction and osteomyelitis. The two deaths occurred within 48 h of implantation were related to raised intracranial pressure (one venous infarction, one unexplained). Complications were associated with maximal size of grid (p < 0.001), greater number of electrodes (p < 0.001), electrode density per cortical surface implanted (p < 0.001), right central surface implantation (p = 0.003) and left central surface implantation (p = 0.013). Multiple logistic regression identified larger size grids and right central surface implantation as independent predictors of complications. CONCLUSION: There are significant complications during intracranial EEG evaluations but the majority of these are transient. We found a relationship between the size of the electrode arrays and the incidence of complications. The results of this study have been used to modify our implantation and monitoring protocols.
BACKGROUND: Intracranial electrode monitoring is still required in epilepsy surgery; however, it is associated with significant morbidity. OBJECTIVE: To identify risk factors associated with complications during invasive intracranial EEG monitoring. MATERIALS AND METHODS: Retrospective study of all patients undergoing invasive monitoring at Westmead between 1988-2004. From detailed chart reviews, the following variables were recorded: duration of intracranial monitoring, the site of grid implantation, number of grids and electrodes, seizure frequency, postoperative complications and seizure outcome. RESULTS: Seventy-one patients (median age: 24 years) underwent subdural electrode implantation; 62% had extratemporal lobe epilepsy and 46% were non-lesional. Of the 58 monitored patients who had cortical resections, 45 had good seizure outcomes. Complications related to subdural electrode implantation included transient complications requiring no treatment (12.7%), transient complications requiring treatment (9.9%) and two deaths (2.8%). Specific complications included subdural haemorrhage, transient neurological deficit, infarction and osteomyelitis. The two deaths occurred within 48 h of implantation were related to raised intracranial pressure (one venous infarction, one unexplained). Complications were associated with maximal size of grid (p < 0.001), greater number of electrodes (p < 0.001), electrode density per cortical surface implanted (p < 0.001), right central surface implantation (p = 0.003) and left central surface implantation (p = 0.013). Multiple logistic regression identified larger size grids and right central surface implantation as independent predictors of complications. CONCLUSION: There are significant complications during intracranial EEG evaluations but the majority of these are transient. We found a relationship between the size of the electrode arrays and the incidence of complications. The results of this study have been used to modify our implantation and monitoring protocols.
Authors: Alan D Degenhart; James Eles; Richard Dum; Jessica L Mischel; Ivan Smalianchuk; Bridget Endler; Robin C Ashmore; Elizabeth C Tyler-Kabara; Nicholas G Hatsopoulos; Wei Wang; Aaron P Batista; X Tracy Cui Journal: J Neural Eng Date: 2016-06-28 Impact factor: 5.379