Usefulness of the H-Reflex for Intraoperative Monitoring of Thoracoabdominal Aneurysms.

PURPOSE: Intraoperative neurophysiologic monitoring in thoracoabdominal aneurysms (TAAA) is essential to avoid intraoperative spinal cord injury). Motor and somatosensory evoked potentials may be considered intraoperative tools for detecting spinal cord injury. H-reflex is a well-known neurophysiologic technique to evaluate L5-S1 root. Current evidence supports the observation that H-reflex changes may occur with spinal cord damage as high as the cervical level. This study aimed to evaluate the usefulness of the H-reflex in these surgeries. METHODS: The use of intraoperative H-reflex in TAAA monitoring was evaluated in 12 patients undergoing open or endovascular repair of TAAA for a period of four years (2016-2020) using somatosensory evoked potentials (SSEPs) and transcranial motor evoked potentials (TcMEPs) and bilateral H-reflex. RESULTS: Six neurophysiologic alarms were recorded in five of the 12 patients. Summarizing the neurophysiologic changes of our series, we considered a peripheral change when we detected a unilateral loss of SSEPs, TcMEPs, and H-reflex. Instead, we assumed a central change when we detected a unilateral or bilateral loss of TcMEPs and H-reflex with normal SSEPs, which we considered a sign of spinal cord ischemia. Interestingly H-reflex always changed significantly in combination with TcMEPs in the same fashion. CONCLUSIONS: According to our series, H-reflex can detect intraoperative changes with the same sensitivity as TcMEPs in TAAA surgeries. With the support of other techniques, it can be useful to localize the origin of the lesion (peripheral or central spinal cord), to help in surgical decision-making to avoid postoperative neurologic damage. Based on our results, we recommend the systematic use of H-reflex in TAAA surgeries.

Retrospective Analysis of EEG in Patients With COVID-19: EEG Recording in Acute and Follow-up Phases.

Background. Interest in electroencephalographic (EEG) coronavirus disease 2019 (COVID-19) findings has been growing, especially in the search for a specific-features EEG of encephalopathy. Methods. We made a retrospective analysis of 29 EEGs recorded in 15 patients with COVID-19 and neurological symptoms. We classified the EEGs as "Acute EEG" and "follow-up EEG." We did a statistical analysis between voltage and respiratory status of the patient, stay or not in the intensive care unit (ICU), days of stay in the ICU, sedative drugs, pharmacological treatment, type of symptoms predominating, and outcome. Results. We found EEG abnormalities in all patients studied. We observed the amplitude of background <20 µV at 93% of "acute EEG," versus only 21.4% of "follow-up EEG." The average voltage went from 12.33 ± 5.09 µV in the acute EEGs to 32.8 ± 20.13 µV in the follow-up EEGs. A total of 60% of acute EEGs showed an intermittent focal rhythmic. We have not found a statistically significant association between voltage of acute EEG and nonneurological clinical status (including respiratory) that may interfere with the EEG findings. Conclusions. Nonspecific diffuse slowing EEG pattern in COVID-19 is the most common finding reported, but we found in addition to that, as a distinctive finding, low voltage EEG, that could explain the low prevalence of epileptic activity published in these patients. A metabolic/hypoxic mechanism seems unlikely on the basis of our EEG findings. This pattern in other etiologies is reminiscent of severe encephalopathy states associated with poor prognosis. However, an unreactive low voltage pattern in COVID-19 patients is not necessarily related to poor prognosis.

[Intraoperative neurophysiological monitoring in radical prostatectomy and pudendal nerve surgical releasing.] / Monitorización neurofisiológica intraoperatoria en prostatectomía radical y liberación del nervio pudendo.

OBJECTIVE: Intraoperative neurophysiological monitoring (INM) allows obtaining real-time information on the functional integrity of nervous system structures. The objective of this article is to present the role of clinical neurophysiology in Urology in the identification and preservation, on the one hand, of the prostate neurovascular bundles in radical prostatectomy (RP), and of the pudendal nerve in the release of this in Pudendal Nerve Entrapment Syndrome (PNS). METHODS: A bipolar laparoscopic probe was used for intraoperative stimulation for both the identification in PNS and neurovascular bundles in RP, obtaining response at the external anal sphincter in the first one; and intracavernous pressure in the second through needle electrodes. RESULTS: Preservation of the periprostatic neurovascular bundles allows to increase rates of sexual potency and urinary continence after surgery. However, it has been shown that the innervation of the corpora cavernosa and the urinary sphincter has a variable disposition. Intraoperative neurostimulation allows the most precise identification and dissection of the vascular and nervous structures that surround the prostate. In the diagnosis of PNS, the neurophysiological study allows to rule out pathology at other levels, such as, primary muscular pathology of the anal sphincter. There are no pathognomonic neurophysiological findings of PNS. In addition, it allows the identification of the nerve during the laparoscopic release of the nerve at the entrance of the Alcock channel, as well as the evaluation of its functional integrity after the end of the dissection. CONCLUSIONS: The INM is a fundamental tool to allow an improved identification of nerve structures during RP and PNS in order to preserve them. It also helps with the diagnosis of PNS.

OBJETIVO: La monitorización neurofisiológica intraoperatoria (MNI) permite obtener información en tiempo real sobre la integridad funcional de las estructuras del sistema nervioso. El objetivo de este trabajo exponer el papel de neurofisiología clínica en Urología en la identificación y preservación, por un lado, de los haces neurovasculares prostáticos en la prostatectomía radical (PR), y del nervio pudendo en la liberación de este en el Síndrome de Atrapamiento del Nervio Pudendo (SANP).MÉTODOS: Se empleó una sonda bipolar laparoscópica para la estimulación intraoperatoria tanto para la identificación en SANP como de haces neurovasculares en PR obteniéndose respuesta a nivel del esfínter anal en la primera y presión intracavernosa en la segunda por medio de electrodos de aguja. RESULTADOS: La presentación de los haces neurovasculares periprostáticos permite aumentar las tasas de potencia sexual y continencia urinaria. Si bien, posteriormente, se evidenció que la inervación de los cuerpos cavernosos y el esfínter urinario tiene disposición variable. La neuroestimulación intraoperatoria permite la identificación y disección más precisa de las estructuras vasculonerviosas que circundan la próstata. En el diagnóstico del SANP, el estudio neurofisiológico permite descartar patología a otros niveles, como por ejemplo patología primaria muscular del esfínter anal; así como, valorar las ramas del nervio pudendo. No existen hallazgos neurofisiológicos patognomónicos del SANP. Además, permite la identificación del nervio durante la liberación laparoscópica del nervio a la entrada del canal de Alcock, así como la evaluación de su integridad funcional tras finalizar la disección. CONCLUSIONES: La MNI es una herramienta fundamental para permitir una mejora en la identificación de estructuras nerviosas durante PR y SANP para poder preservarlas. Así mismo, ayuda con el diagnóstico de SANP.

Monitorización neurofisiológica intraoperatoria en prostatectomía radical y liberación del nervio pudendo / Intraoperative neurophysiological monitoring in radical prostatectomy and pudendal nerve surgical releasing

Objetivo: La monitorización neurofisiológica intraoperatoria (MNI) permite obtener información en tiempo real sobre la integridad funcional de las estructuras del sistema nervioso. El objetivo de este trabajo exponer el papel de neurofisiología clínica en Urología en la identificación y preservación, por un lado, de los haces neurovasculares prostáticos en la prostatectomía radical (PR), y del nervio pudendo en la liberación de este en el Síndrome de Atrapamiento del Nervio Pudendo (SANP). Métodos: Se empleó una sonda bipolar laparoscópica para la estimulación intraoperatoria tanto para la identificación en SANP como de haces neurovasculares en PR obteniéndose respuesta a nivel del esfínter anal en la primera y presión intracavernosa en la segunda por medio de electrodos de aguja. Resultados: La presentación de los haces neurovasculares periprostáticos permite aumentar las tasas de potencia sexual y continencia urinaria. Si bien, posteriormente, se evidenció que la inervación de los cuerpos cavernosos y el esfínter urinario tiene disposición variable. La neuroestimulación intraoperatoria permite la identificación y disección más precisa de las estructuras vasculonerviosas que circundan la próstata. En el diagnóstico del SANP, el estudio neurofisiológico permite descartar patología a otros niveles, como por ejemplo patología primaria muscular del esfínter anal; así como, valorar las ramas del nervio pudendo. No existen hallazgos neurofisiológicos patognomónicos del SANP. Además, permite la identificación del nervio durante la liberación laparoscópica del nervio a la entrada del canal de Alcock, así como la evaluación de su integridad funcional tras finalizar la disección. Conclusiones: La MNI es una herramienta fundamental para permitir una mejora en la identificación de estructuras nerviosas durante PR y SANP para poder preservarlas. Así mismo, ayuda con el diagnóstico de SANP

Objective: Intraoperative neurophysiological monitoring (INM) allows obtaining real-time information on the functional integrity of nervous system structures. The objective of this article is to present the role of clinical neurophysiology in Urology in the identification and preservation, on the one hand, of the prostate neurovascular bundles in radical prostatectomy (RP), and of the pudendal nerve in the release of this in Pudendal Nerve Entrapment Syndrome (PNS). Methods: A bipolar laparoscopic probe was used for intraoperative stimulation for both the identification in PNS and neurovascular bundles in RP, obtaining response at the external anal sphincter in the first one; and intracavernous pressure in the second through needle electrodes. Results: Preservation of the periprostatic neurovascular bundles allows to increase rates of sexual potency and urinary continence after surgery. However, it has been shown that the innervation of the corpora cavernosa and the urinary sphincter has a variable disposition. Intraoperative neurostimulation allows the most precise identification and dissection of the vascular and nervous structures that surround the prostate.In the diagnosis of PNS, the neurophysiological study allows to rule out pathology at other levels, such as,primary muscular pathology of the anal sphincter. There are no pathognomonic neurophysiological findings of PNS. In addition, it allows the identification of the nerve during the laparoscopic release of the nerve at the entrance of the Alcock channel, as well as the evaluation of its functional integrity after the end of the dissection. Conclusions: The INM is a fundamental tool to allow an improved identification of nerve structures during RP and PNS in order to preserve them. It also helps with the diagnosis of PN

Clinical and genetical study of a familial form of REM sleep behavior disorder.

OBJECTIVE: We report a kindred with a genetic form of REM behaviour disorder (RBD) with autosomal dominant transmission. PATIENTS AND METHODS: Clinical, polysomnography study, genetic study and brain MRI were performed to evaluate the index patients. The genetic study included exome sequencing of the index cases that detected 60,869 variants in the individuals examined. RESULTS: The kindred has a RBD with autosomal dominant transmission starting in second decade of life. After filtering out the exome variants shared by two affected cases the pool of variants could be reduced to thirteen; one of them is in PVALB, a calcium-binding albumin protein present in gabaergic interneurons in the nervous system that inhibit the pyramidal cell during REM sleep. CONCLUSIONS: RBD can have a genetic origin. The results of the exome study in this kindred suggest that gabaergic circuits may be altered in patients with RBD. Further studies in this family or in other pedigrees with familial RBD may clear the role of this gene in this disorder.

Novel Mapping Method for the Intraoperative Neurophysiologic Monitoring of Sexual Function During Prostate Surgery.

PURPOSE: The occurrence of urinary incontinence and erectile dysfunction after surgical treatment for prostate cancer is a significant and lingering problem. The aim of this study is to revise and improve older techniques of intraoperative cavernous nerve mapping already in use to improve accuracy and reliability. METHODS: We prospectively studied this technique in 12 patients suffering from prostate cancer. Inhalation or intravenous anesthetic regimen was used with nondepolarizing muscle relaxants. Stimulation protocol was 30 Hz, 0.2 ms, 10 to 20 mA intensity and a maximum duration of 30 seconds. Recording was performed with a system for measuring pressure changes using a stainless steel needle electrode inside the cavernous bodies. Stimulation was systematically performed at three distinct moments during the surgery at various points. An increase or decrease in pressure of 4 cm of H20 in the cavernous bodies was considered a positive result and negative response when no changes occurred after 30 seconds of continuous stimulation. RESULTS: Of patients, 91.6% had positive responses to initial stimulation. The anesthetic regimen did not appear to significantly influence the responses in our series. CONCLUSIONS: In light of the results of this study, the stimulation of the cavernous nerves may be a viable technique in the right context, which includes good patient selection (young patients with a localized tumor and with preserved potency). The major limitation is that mapping techniques are useful to localize functional nerves, but not to monitor function in a continuous manner.

Large Amplitude Cortical Evoked Potentials in Nonepileptic Patients. Reviving an Old Neurophysiologic Tool to Help Detect CNS Pathology.

PURPOSE: Although large amplitude evoked potentials (EPs) are typically associated with progressive myoclonic epilepsy patients, giant EPs imply central nervous system (CNS) hyperexcitability and can be seen in various nonepileptic disorders. METHODS: We performed a retrospective chart review including history, physical examination, imaging and diagnostic studies of nonepileptic patients with large amplitude somatosensory evoked potentials (SSEPs) and visual evoked potentials (VEPs) during 2007 to 2013. Large amplitude EPs were defined as follows: VEPs (N75-P100) >18 µV; and SSEPs (N20-P25) >6.4 µV. Recording montage for VEPs was Oz-Cz and SSEPs C3'/C4'-Fz. RESULTS: Fifty-two patients (33 females, 19 males; age range, 9-90 years) were identified. No CNS pathology was detected in 7 patients. All remaining patients were diagnosed with new CNS disorders including: vascular (37%); myelopathies (13%); demyelinating (11%); space occupying lesions (8.7%); syringomyelia (8.7%); hydrocephalus (6.5%); Vitamin B-12 deficiency (4.3%); multiple system atrophy (4.3%); and toxins (2.2%). CONCLUSIONS: This study supports the notion that large amplitude EP implies CNS hyperexcitability and CNS disease. These results confirm the utility of EP studies in patients with suspected CNS pathology.