Intraoperative monitoring of facial corticobulbar motor evoked potentials: Methodological improvement and analysis of 100 patients.

OBJECTIVE: A) To describe an improved methodology for continuously monitoring the functional integrity of facial nerve by eliciting facial corticobulbar motor-evoked potentials (FCoMEP) and B) To establish the prognosis of facial nerve function based on changes in FCoMEP during skull base surgery. METHODS: Intraoperative monitoring of FCoMEP performed in 100 patients. Previously published methodology has been improved upon by a) doing preoperative mapping of the facial nerve, b) facilitating the corticobulbar tract (CBT) by continuous transcranial electrical stimulation (TES) at 2 Hz repetition rate, c) recording from multiple facial nerve innervated muscles, and d) eliciting blink reflex (BR). We analyzed changes in FCoMEP, comparing them with the clinical facial nerve outcome scored with the House-Brackman (HB) scale. RESULTS: The monitorability rate was 100%. Out of 100 patients, nine presented a new facial deficit after surgery. Eight of these showed significant changes in FCoMEP. In four patients FCoMEPs were lost; they presented a complete facial paralysis from which they did not recover. To discriminate the prognosis of patients, ROC analysis identified a cut-off at 65% for FCoMEPs amplitude decrease with a sensitivity of 89% and specificity of 99%. In four patients FCoMEP showed a decrease in amplitude greater than 65%, and they presented mild/moderate facial paresis that was transient. One patient did not present changes in FCoMEP but had a mild facial paresis from which the patient recovered. CONCLUSIONS: The improved methodology allows the maximum rate of monitorability and minimizes false positive and false negative results. This study shows that prognosis of facial nerve may be reliably established based on FCoMEP parameters. SIGNIFICANCE: We improved the previously described methodology for continuously monitoring the functional integrity of the facial nerve by increasing the monitorability rate, and we describe the impact of FCoMEP intraoperative management of facial nerve. This method may permit establishing the short-term and long-term prognosis of facial nerve function in skull base surgery.

Evaluation of multimodal intraoperative neurophysiologic monitoring during supratentorial aneurysm surgery: a comparative study.

The objective of this study is to determine the role of multimodal intraoperative neurophysiologic monitoring (IONM) in the overall outcome of intracranial aneurysms surgery, and the risk factors associated with ischemic complications. We grouped 268 ruptured and unruptured intracranial aneurysms surgically treated at our institution into 2 cohorts, based on the use of IONM (180; 67.16%) or non-use of IONM (88; 32.84%). The IONM technique used was multimodal: electroencephalogram (EEG), somatosensory evoked potentials (SSEPs), transcranial (TES), and direct cortical (DCS) stimulation motor evoked potentials (MEPs). There was a significant difference, with a reduction in perioperative strokes (p = 0.011) and better motor surgery-related outcome in the IONM group (p = 0.016). Independent risk factors identified for surgery ischemic complications were temporary clipping time ≥ 6'05″ (odds ratio [OR]: 3.03; 95% CI: 1.068-8.601; p = 0.037), aneurysm size ≥ 7.5 mm (OR: 2.65; 95% CI: 1.127-6.235; p = 0.026), and non-use of IONM (OR: 2.79; 95% CI: 1.171-6.636; p = 0.021). Conversely, aneurysm rupture was not detected as an independent risk factor (OR: 2.5; 95% CI: 0.55-4.55; p = 0.4). Longer temporary clipping time, larger aneurysm size, and the non-use of IONM could be considered as risk factors for ischemic complications during microsurgical clipping. A standardized designed protocol including multimodal IONM with DCS provides continuous information about blood supply and allows reduction of treatment-related morbidity. Multimodal IONM is a valuable technique in intracranial aneurysm surgery.

Sleep quality and daytime sleepiness in patients treated with adjunctive perampanel for focal seizures.

PURPOSE: The purpose of this study was to evaluate subjective sleep quality and daytime sleepiness in patients receiving adjunctive perampanel for focal seizures. METHODS: We conducted a multicenter, prospective, interventional, open-label study in patients aged >16 with focal seizures who received adjunctive perampanel (flexible dosing: 2-12mg). Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI) and daytime sleepiness with the Epworth Sleepiness Scale (ESS) at baseline and 3 and 6months after initiating perampanel. Patients with modifications in their baseline AEDs or sleep medications were excluded. RESULTS: In 72 patients with drug-resistant focal seizures, mean baseline PSQI score (±standard deviation) was 7.26 (±4.6), and ESS was 6.19 (±4.2). At 3months (median perampanel dose: 4mg), there was no significant mean change from baseline in ESS score (n=61) and a significant improvement in PSQI (-1.51 points; n=44; p=0.007), driven mainly by improved sleep efficiency (p=0.012). In the 31 patients with 6-month data, ESS (but not PSQI) improved significantly at 6months vs baseline (p=0.029). The only factor significantly correlated with sleep parameters was number of baseline AEDs (higher number correlated with worse daytime sleepiness). Seizure frequency was reduced significantly from baseline at 3 and 6months. In bivariate analysis, neither PSQI nor ESS was associated with seizure frequency, suggesting that the changes in daytime sleepiness and sleep quality may be independent of the direct effect on seizures. CONCLUSION: Adjunctive perampanel did not worsen sleep quality or daytime sleepiness at 3months and reduced daytime sleepiness in patients continuing perampanel for 6months. Perampanel may be a suitable AED in patients with sleep disorders, in addition to refractory focal seizures.