Somatic complications of epilepsy surgery over 25 years at a single center

•Epilepsy surgery carries well defined surgical and neurological risks, which need to be balanced against the risks of morbidity and mortality from continued seizures, and the chances of seizure remission with surgery.•The frequency of unexpected persistent neurological adverse events, which can affect quality of life, was 2.2% following epilepsy surgery.•Subdural EEG recordings were associated with increased risk of serious site-specific infection.

IntroductionEpilepsy surgery is an effective treatment for refractory focal epilepsy. Risks of surgery need to be considered when advising individuals of treatment options. We describe the frequency and nature of physical adverse events associated with epilepsy surgery in a single center.Material and methodsWe reviewed the prospectively maintained records of adults who underwent epilepsy surgery at our center between 1990 and 2014 to identify peri/postsurgical adverse events. These were categorized into neurological deficits and those related to surgery (e.g. wound infections). Neurological deficits were categorized as expected or unexpected and into transient (≤3 months) or persistent (>3 months),ResultsThere were 911 procedures with no peri-operative deaths. Persistent neurological adverse events were seen following 157 (17.2%) procedures. The most common persistent expected complication was quadrantanopia after temporal lobe resections (72/764, 9.4%). Unexpected persistent neurological complications occurred in 20 procedures (2.2%) and included: quadrantanopia (6, 0.7%); hemianopia (2, 0.2%); hemi/mono-paresis/sensory loss (9, 1%); dysphasia (10, 1%); frontalis muscle weakness (2, 0.2%); and oculomotor weakness (1, 0.1%).106 surgery related adverse events occurred in 83 procedures, with severe infections requiring bone-flap removal in 24 (2.6%) procedures and intracranial infections in 8 (0.9%). The risk of post-resective severe infection increased by 4 fold (OR 4.32, 95% CI 2.1-8.9, p < 0.001) with use of subdural EEG monitoring prior to resection. In consequence, in August 2011 we introduced antibiotic coverage in all individuals undergoing intracranial monitoring. Also, after August 2011 there was greater use of Stereo-EEG (SEEG) than subdural (OR 9.0 CI 0.36-224.2, p = 0.18 ns). One complicated by severe infection. Other surgical complications included haematoma (0.3%), hydrocephalus (0.3%) and CSF leak (1.2%). None had permanent complications.ConclusionsAdverse event rates are similar to other series. Epilepsy surgery carries well defined surgical and neurological risks. The risks of somatic adverse events, in addition to neuropsychiatric and neuropsychological complications need to be made clear to individuals considering this treatment option.