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Retractors and scopes used in head and neck surgery to provide adequate surgical exposure also deform critical structures in the region. Surgeons typically use preoperative imaging to plan and guide their tumor resections, however the large tissue deformation resulting from placement of retractors and scopes reduces the utility of preoperative imaging as a reliable roadmap. We quantify the extent of tumor and vasculature deformation in patients with tumors of the larynx and pharynx undergoing diagnostic laryngoscopy. A mean tumor displacement of 1.02 cm was observed between the patients’ pre- and intra-operative states. Mean vasculature displacement at key bifurcation points was 0.99 cm. Registration to the hyoid bone can reduce tumor displacement to 0.67 cm and improve carotid stem angle deviations but increase overall vasculature displacement. The large deformation results suggest limitations in reliance on preoperative imaging and that using specific landmarks intraoperatively or having more intraoperative information could help to compensate for these deviations and ultimately improve surgical success.

Cerebral tissue oxygenation (oxygen tension, pO2) is a critical parameter that is closely linked to brain metabolism, function, and pathophysiology. In this work, we have used electron paramagnetic resonance oximetry with a deep-tissue multi-site oxygen-sensing probe, called implantable resonator, to monitor temporal changes in cerebral pO2 simultaneously at four sites in a rabbit model of ischemic stroke induced by embolic clot. The pO2 values in healthy brain were not significantly different among the four sites measured over a period of 4 weeks. During exposure to 15% O2 (hypoxia), a sudden and significant decrease in pO2 was observed in all four sites. On the other hand, brief exposure to breathing carbogen gas (95% O2 + 5% CO2) showed a significant increase in the cerebral pO2 from baseline value. During ischemic stroke, induced by embolic clot in the left brain, a significant decline in the pO2 of the left cortex (ischemic core) was observed without any change in the contralateral sites. While the pO2 in the non-infarct regions returned to baseline at 24-h post-stroke, pO2 in the infarct core was consistently lower compared to the baseline and other regions of the brain. The results demonstrated that electron paramagnetic resonance oximetry with the implantable resonator can repeatedly and simultaneously report temporal changes in cerebral pO2 at multiple sites. This oximetry approach can be used to develop interventions to rescue hypoxic/ischemic tissue by modulating cerebral pO2 during hypoxic and stroke injury.

Purpose: To report orgasmic epilepsy as a manifestation of paraneoplastic limbic encephalitis in a patient with small cell lung cancer. Case report: A 57 years-old woman presented with 2 month history of daily spells that consisted of a sudden pleasure provoking feeling described ‘like an orgasm’ lasting for 30 s to 1 min. She was a heavy smoker and had noted recent weight loss. Bronchial biopsy, following the finding of a right lung mass, confirmed the diagnosis of small cell lung cancer (SCLC). Spells subsided after starting carbamazepine. The lung cancer was treated with chemotherapy and chest radiation therapy resulting in a complete radiologic response. Results: Brain magnetic resonance imaging (MRI) revealed left temporal lobe area of increased signal on T2 and FLAIR sequence. T1-weighted images after contrast administration demonstrated a circumscribed area of enhancement in the left anterior medial temporal lobe. Electroencephalogram (EEG) showed focal left mid-temporal sharp waves and intermittent slowing. Anti-Hu antibodies were detected in her serum supporting a diagnosis of paraneoplastic limbic encephalitis as the cause of her orgasmic epilepsy. The patient has been followed for 2 years after treatment without tumor recurrence or neurological deterioration. Conclusion: Orgasmic epilepsy is another mode of presentation of paraneoplastic limbic encephalitis leading to the diagnosis of an occult SCLC. EEG and MRI findings suggest that in this case the seizures originated from the left hemisphere. It is possible that early recognition and treatment of the SCLC will improve the prognosis of this neurologic entity.