Blood-Brain Barrier Opening in Primary Brain Tumors with Non-invasive MR-Guided Focused Ultrasound: A Clinical Safety and Feasibility Study.

The blood-brain barrier (BBB) has long limited therapeutic access to brain tumor and peritumoral tissue. In animals, MR-guided focused ultrasound (MRgFUS) with intravenously injected microbubbles can temporarily and repeatedly disrupt the BBB in a targeted fashion, without open surgery. Our objective is to demonstrate safety and feasibility of MRgFUS BBB opening with systemically administered chemotherapy in patients with glioma in a phase I, single-arm, open-label study. Five patients with previously confirmed or suspected high-grade glioma based on imaging underwent the MRgFUS in conjunction with administration of chemotherapy (n = 1 liposomal doxorubicin, n = 4 temozolomide) one day prior to their scheduled surgical resection. Samples of "sonicated" and "unsonicated" tissue were measured for the chemotherapy by liquid-chromatography-mass spectrometry. Complete follow-up was three months. The procedure was well-tolerated, with no adverse clinical or radiologic events related to the procedure. The BBB within the target volume showed radiographic evidence of opening with an immediate 15-50% increased contrast enhancement on T1-weighted MRI, and resolution approximately 20 hours after. Biochemical analysis of sonicated versus unsonicated tissue suggest chemotherapy delivery is feasible. In this study, we demonstrated transient BBB opening in tumor and peritumor tissue using non-invasive low-intensity MRgFUS with systemically administered chemotherapy was safe and feasible. The characterization of therapeutic delivery and clinical response to this treatment paradigm requires further investigation.

e-Consent: approaching surgical consent with mobile technology

Background: Patient recall of information about procedures, including risks and benefits and potential outcomes, is often insufficient. We sought to determine whether a multimedia educational tool enhances the informed consent discussion for elective neurosurgical procedures by increasing patient knowledge of the procedure. Methods: Adult patients from a single neurosurgical site eligible for 4 neurosurgical procedures (lumbar spine or cervical spine decompression for degenerative disease, craniotomy for brain tumour or trigeminal neuralgia treatment) were offered enrolment. Patients were randomly assigned to either the control arm (standard consent discussion) or the intervention arm (review of an e-book containing information tailored to their disease/injury plus standard consent discussion). Participants completed a 14-item questionnaire before and after the consent discussion. Results: Questionnaires were completed by 38 participants, 18 in the control group and 20 in the intervention group. The mean age was 62.2 (standard deviation [SD] 13.6) years and did not differ significantly between the 2 groups. The mean baseline questionnaire scores were similar for the control and intervention groups (20.4 [SD 7.3] v. 20.6 [SD 6.7]). However, the mean scores on the follow-up questionnaire were significantly different between the 2 groups (20.2 [SD 4.0] v. 23.2 [SD 4.9], p = 0.02). There was no change in the scores on the 2 questionnaires in the control group, whereas, in the intervention group, the mean score was significantly higher after the intervention (p = 0.03). Conclusion: The use of an electronic booklet appears to improve patients' knowledge of their surgical procedure. The use of multimedia booklets in clinical practice could help standardize and optimize the consent process, ensuring that patients receive the relevant information to make a truly informed decision.

Contexte: Ce que les patients retiennent au sujet de leurs interventions, incluant les risques, les avantages et les résultats potentiels sont souvent insuffisants. Nous avons voulu déterminer si un outil d'enseignement multimédia peut faciliter la discussion entourant le consentement éclairé en prévision d'interventions neurochirurgicales non urgentes, en renseignant davantage les patients au sujet de leurs interventions. Méthodes: On a invité les patients adultes d'un centre de neurochirurgie admissibles à 4 types de différents d'interventions neurochirurgicale (décompression de la colonne lombaire ou cervicale pour maladie dégénérative, craniotomie pour tumeur cérébrale ou traitement de la névralgie du trijumeau) à s'inscrire à l'étude. Les patients ont été assignés aléatoirement soit au groupe témoin (discussion standard sur le consentement), soit au groupe soumis à l'intervention (utilisation d'une publication électronique contenant de l'information adaptée à leur maladie/lésion en plus de la discussion standard sur le consentement). Les participants ont répondu à un questionnaire en 14 points avant et après la discussion sur le consentement. Résultats: Trente-huit participants ont répondu au questionnaire, 18 dans le groupe témoin et 20 dans le groupe soumis à l'intervention. L'âge moyen était de 62,2 ans (écart-type [É.-T.] 13,6 ans) et n'était pas significativement différent entre les 2 groupes. Les scores moyens au questionnaire de départ étaient similaires pour les 2 groupes (20,4 [É.-T. 7,3] c. 20,6 [É.-T. 6,7]). Par contre, les scores moyens au questionnaire de suivi ont été significativement différents entre les 2 groupes (20,2 [É.-T. 4,0] c. 23,2 [É.-T. 4,9], p = 0,02). On n'a observé aucun changement des scores entre les 2 questionnaires du groupe témoin, tandis que dans le groupe soumis à l'intervention, le score moyen a été significativement plus élevé après l'intervention (p = 0,03). Conclusion: L'utilisation d'un document électronique semble améliorer les connaissances des patients au sujet de leurs interventions chirurgicales. L'utilisation de documents multimédias dans la pratique clinique pourrait aider à standardiser et optimiser le processus de consentement et faire en sorte que les patients reçoivent une information pertinente pour prendre une décision réellement éclairée.

Somatosensory evoked potentials after decompressive craniectomy for traumatic brain injury.

Somatosensory evoked potentials (SSEPs) are used for neuroprognosis after severe traumatic brain injury (TBI). However decompressive craniectomy (DC), involving removal of a portion of the skull to alleviate elevated intracranial pressure, is associated with an increase in SSEP amplitude. Accordingly, SSEPs are not available for neuroprognosis over the hemisphere with DC. We aim to determine the degree to which SSEP amplitudes are increased in the absence of cranial bone. This will serve as a precursor for translation to clinically prognostic ranges. Intra-operative SSEPs were performed before and after bone flap replacement in 22 patients with severe TBI. SSEP measurements were also performed in a comparison non-traumatic group undergoing craniotomy for tumor resection. N20/P25 amplitudes and central conduction time were measured with the bone flap in (BI) and out (BO). Linear regressions, adjusting for skull thickness and study arm, were performed to evaluate the contribution of bone presence to SSEP amplitudes. Latencies were not different between BO or BI trials in either group. Mean N20/P25 amplitudes recorded with BO were statistically different (p = 0.0001) from BI in both cohorts, showing an approximate doubling in BO amplitudes. For contralateral-ipsilateral montages r2 was 0.28 and for frontal pole montages r2 was 0.62. Cortical SSEP amplitudes are influenced by the presence of cortical bone as is particularly evident in frontal pole montages. Larger, longitudinal trials to assess feasibility of neuroprognosis over the hemisphere with DC in severe TBI patients are warranted.

Generalized peripheral nerve failure during thoracic spine surgery: a case report.

OBJECTIVE: Intra-operative systemic changes impairing peripheral nerve function are not commonly detected with electrophysiology. This case presentation illustrates how somatosensory evoked potential (SSEP) monitoring can detect global changes in peripheral nerve excitability during spine surgery. METHODS: A posterior thoracic spine fixation was performed on a young male with multiple traumatic injuries. Bilateral tibial nerve SSEPs were intraoperatively recorded, along with the right median nerve SSEP for control. RESULTS: A rapid, progressive loss of tibial and median nerve potentials (followed by cortical SSEP loss) occurred 90 min after anaesthetic induction. Oxygenation and fluid volume were adequate throughout the case, despite mean airway resistance being elevated (33 cmH(2)0) and blood pressure being low (80/45 mmHg). Corresponding to the decrease in peripheral nerve responses was a drop in end-tidal CO(2) partial pressure (PaCO(2)) from 37 to 25 mmHg. Approximately, 100 min later, the peripheral and cortically generated SSEPs recovered in 2 of 3 limbs monitored. On emergence from anesthesia it was clear that the patient had bitten and kinked the endotracheal tube thus increasing the airway resistance. Ventilation difficulties were magnified with the patient's prone position. Post-operatively there were no sensorimotor deficits. CONCLUSIONS: Somatosensory evoked potential monitoring during spine surgery can detect uncommon generalized nerve conduction block, and further alert surgical teams to a systemic impairment. This was discovered to result from a compromised endotracheal tube. This can apply in various monitoring situations, as the changes affecting the SSEPs were not related to surgical manipulation.

A novel method in predicting immediate postoperative facial nerve function post acoustic neuroma excision.

UNLABELLED: To determine whether the percentage calculated by dividing the amplitude of postexcision direct facial nerve stimulus responses (at pontomedullary junction) by the amplitude of distal ipsilateral transcutaneous (stylomastoid region) maximal stimulus responses and response amplitude progression by increasing stimulus intensities have predictive value for determining normal or near-normal (House-Brackmann Grade 1 or 2) immediate postoperative facial nerve function. STUDY DESIGN: Intraoperative recordings of three muscle groups: 1) frontalis, 2) orbicularis oculi, and 3) orbicularis oris. Postexcision direct facial nerve stimulation at the pontomedullary junction and transcutaneous maximal facial nerve stimulation at the ipsilateral stylomastoid region and their associated response amplitudes were recorded. SETTING: Tertiary referral center. PATIENTS AND METHODS: Patients who underwent acoustic neuroma surgery from January 2004 to March 2006 with intraoperative facial nerve monitoring and an intact facial nerve after tumor excision were included. Recordings were available for 38 patients. RESULTS: With a stimulus intensity of 0.3 mA at the root exit zone, there was an 81% positive predictive value in patients that exhibited a compound action potential of greater than 20% of maximum (sensitivity, 81%). This increased to 93% when the compound action potential was greater than 50% of maximum. When the amplitude increase was greater than 5 microV, there was a 77% positive predictive value (sensitivity, 87%). CONCLUSION: The percentage of the response amplitude of direct facial nerve stimulation at the pontomedullary junction when compared with the maximum response amplitude of ipsilateral transcutaneous stimulation at the stylomastoid foramen is a good predictor of normal to near-normal immediate postoperative facial nerve function. Progression of amplitude response also seems to be a good predictor of normal to near-normal immediate postoperative facial nerve function.