Neurosurgical Education Using Cadaver-Free Brain Models and Augmented Reality: First Experiences from a Hands-On Simulation Course for Medical Students.

Background and Objectives: Neurosurgery has been underrepresented in the medical school curriculum. Advances in augmented reality and 3D printing have opened the way for early practical training through simulations. We assessed the usability of the UpSurgeOn simulation-based training model and report first experiences from a hands-on neurosurgery course for medical students. Materials and Methods: We organized a two-day microneurosurgery simulation course tailored to medical students. On day one, three neurosurgeons demonstrated anatomical explorations with the help of life-like physical simulators (BrainBox, UpSurgeOn). The surgical field was projected onto large high-definition screens by a robotic-assisted exoscope (RoboticScope, BHS Technologies). On day two, the students were equipped with microsurgical instruments to explore the surgical anatomy of the pterional, temporal and endoscopic retrosigmoid approaches. With the help of the RoboticScope, they simulated five clipping procedures using the Aneurysm BrainBox. All medical students filled out a digital Likert-scale-based questionnaire to evaluate their experiences. Results: Sixteen medical students participated in the course. No medical students had previous experience with UpSurgeOn. All participants agreed that the app helped develop anatomical orientation. They unanimously agreed that this model should be part of residency training. Fourteen out of sixteen students felt that the course solidified their decision to pursue neurosurgery. The same fourteen students rated their learning experience as totally positive, and the remaining two rated it as rather positive. Conclusions: The UpSurgeOn educational app and cadaver-free models were perceived as usable and effective tools for the hands-on neuroanatomy and neurosurgery teaching of medical students. Comparative studies may help measure the long-term benefits of UpSurgeOn-assisted teaching over conventional resources.

Space-expanding flap in decompressive hemicraniectomy for stroke.

OBJECTIVE: Decompressive hemicraniectomy (DCE) is the standard of care for space-occupying malignant infarction of the medial cerebral artery in suitable patients. After DCE, the brain is susceptible to trauma and at risk for the syndrome of the trephined. This study aimed to assess the feasibility of using temporary space-expanding flaps, implanted during DCE, to shield the brain from these risks while permitting the injured brain to expand. METHODS: The authors performed a prospective feasibility study to analyze the safety of space-expanding flaps in 10 patients undergoing DCE and evaluated clinical and radiological outcomes. RESULTS: The relatives of 1 patient withdrew consent, leaving 9 patients in the final analysis. No patients required removal of the space-expanding flap because of uncontrolled increase of intracranial pressure or infection. One patient required additional external ventricular drainage and 1 received mannitol. The mean (range) midline shift decreased from 6.67 (3-12) mm to 1.26 (0-2.6) mm after DCE with the space-expanding flap. The authors observed no cases of sinking skin flap syndrome, other complications, or deaths. One patient underwent further treatment due to infection of the reimplanted autologous bone flap. Two patients later refused cranioplasty, preferring to keep the space-expanding flap and thus avoid the potential risks of cranioplasty. CONCLUSIONS: This feasibility study showed that the concurrent use of space-expanding flaps appeared to be safe in patients who underwent DCE for malignant infarction of the medial cerebral artery. Moreover, space-expanding flaps may permit patients to avoid a second surgery for reimplantation of the autologous bone flap and the risks inherent to this procedure.

Coverage of complex tissue defects following open cervicothoracic spine surgery with a lower trapezius island myocutaneous flap-an interdisciplinary approach.

The study design is a clinical case series. The objective of this study was to present the concept and efficacy of the lower trapezius island myocutaneous flap (LTIMF) for management of complex wound healing disorders following open cervicothoracic spine surgery. Wound healing disturbances with myocutaneous defects after open spine surgery at the cervical and upper thoracic spine are well-described complications. In severe cases, plastic reconstructive coverage is often required as a last resort. A review of all adult patients with deep wound dehiscence and tissue defects following open cervicothoracic spine surgery, who were managed with plastic surgery reconstruction using a LTIMF at our institution, was conducted. Synopses of these cases are presented. Seven patients with a mean age of 73 years ± 13 (range 50 to 89 years) were included in this case series. Six out of seven patients had instrumented posterior fusion added to their decompression. All patients were managed with a LTIMF for wound coverage. No spinal implants were removed prior to LTIMF surgery. The mean follow-up was 5.2 months (± 5.4 months). No major flap failure occurred, and all patients presented with satisfactory cosmetic results. The only minor complication was development of a sterile subcutaneous seroma in two patients, which were successfully managed by puncture and aspiration. The LTIMF is an effective and reliable salvage treatment option for spine surgery patients offering stable coverage of deep tissue defects resulting from complex wound healing disorders at the cervical and upper thoracic spine.

Excessive Premature Atrial Complexes and the Risk of Recurrent Stroke or Death in an Ischemic Stroke Population.

BACKGROUND: Our aim was to investigate the association of premature atrial complexes and the risk of recurrent stroke or death in patients with ischemic stroke in sinus rhythm. METHODS: In a prospective cohort study, we used 24-hour Holter recordings to evaluate premature atrial complexes in patients consecutively admitted with ischemic strokes. Excessive premature atrial complexes were defined as >14 premature atrial complexes per hour and 3 or more runs of premature atrial complexes per 24 hours. During follow-up, 48-hour Holter recordings were performed after 6 and 12 months. Among patients in sinus rhythm, the association of excessive premature atrial complexes and the primary end point of recurrent stroke or death were estimated in both crude and adjusted Cox proportional hazards models. We further evaluated excessive premature atrial complexes contra atrial fibrillation in relation to the primary end point. RESULTS: Of the 256 patients included, 89 had atrial fibrillation. Of the patients in sinus rhythm (n = 167), 31 had excessive premature atrial complexes. During a median follow-up of 32 months, 50 patients (30% of patients in sinus rhythm) had recurrent strokes (n = 20) or died (n = 30). In both crude and adjusted models, excessive premature atrial complexes were associated with the primary end point, but not with newly diagnosed atrial fibrillation. Compared with patients in atrial fibrillation, those with excessive premature atrial complexes had similarly high risks of the primary end point. CONCLUSIONS: In patients with ischemic stroke and sinus rhythm, excessive premature atrial complexes were associated with a higher risk of recurrent stroke or death.

Prevalence and Prognostic Significance of Runs of Premature Atrial Complexes in Ischemic Stroke Patients.

BACKGROUND AND PURPOSE: Runs of premature atrial complexes (PACs) are common in stroke patients and perceived to be clinically insignificant, but their prognostic significance is unclear. This study investigated the association between runs of PACs in ischemic stroke patients and the risk of recurrent ischemic strokes/transient ischemic attacks (TIAs) or death. METHODS: The study included consecutive patients admitted with an ischemic stroke from August 2008 to April 2011. Patients with known and newly detected atrial fibrillation were excluded. Runs of PACs were defined as 3 or more PACs lasting less than 30 seconds during 48 hours of continuous inpatient cardiac telemetry. The patients were followed for 4 years or until death, whichever came first. They were stratified according to stroke severity. The combined primary endpoint was a recurrent ischemic stroke/TIA or death. RESULTS: Of the 565 patients included in the study, 28% had runs of PACs. Patients with runs of PACs were likely to be older, female, and to have experienced more severe strokes. During the follow-up, 210 (37%) patients had a recurrent ischemic stroke/TIA (n = 73) or died (n = 137) respectively. Among the 489 patients who had mild-to-moderate strokes, runs of PACs were associated with recurrent ischemic strokes/TIAs or death (hazard ratio = 1.47; 95% CI 1.06-2.04; P = .023). CONCLUSION: Runs of PACs were frequent in patients with acute ischemic strokes and sinus rhythm, and they were independently associated with an increased risk of recurrent ischemic strokes/TIAs or death in patients with mild-to-moderate strokes.

Left Atrial Sphericity Index Predicts Early Recurrence of Atrial Fibrillation After Direct-Current Cardioversion: An Echocardiographic Study.

BACKGROUND: Attempts to achieve rhythm control using direct-current cardioversion (DCC) are common in those with persistent atrial fibrillation (AF). Although often successful, AF recurs within 1 month in as many as 57% of patients. The aim of this study was to assess whether a baseline left atrial sphericity index (LASI) acquired by 2-dimensional transthoracic echocardiography (TTE) could be used as a predictor of AF recurrence after successful DCC. HYPOTHESIS: A baselline LASI assessed by 2D TTE can predict AF recurrence after successful DCC in patients with persistent AF. METHODS: A total of 124 consecutive patients with persistent AF lasting <120 days underwent successful DCC. Other than ß-blockers, no other antiarrhythmic treatment was administered. Prior to DCC, all patients underwent thorough TTE, and LASI was calculated as the fraction of the left atrial width/length of the largest possible left atrial volume in a 4-chamber view. The primary outcome was a TTE-estimated baseline LASI as a predictor of AF recurrence after successful DCC for persistent AF. RESULTS: Anatomically, a more spherical shape of the left atrium (LASI >0.9) proved to be a strong and independent predictor of AF recurrence, with an odds ratio between 4.1 (95% confidence interval: 1.6-11.9, P = 0.005) and 7.6 (95% confidence interval: 3.3-19.7; P = 7.2 × 10(-6) ). The receiver operating characteristic curve indicated good power for distinguishing between recurring and nonrecurring AF, and we chose a cutoff of 0.9 because high specificity was a priority for clinical reasons. CONCLUSIONS: In conclusion, baseline LASI >0.9 was associated with significantly greater AF recurrence throughout the 12-month follow-up period.

Effect of early direct current cardioversion on the recurrence of atrial fibrillation in patients with persistent atrial fibrillation.

In patients with persistent atrial fibrillation (AF), the sinus rhythm (SR) can be restored by direct current cardioversion (DCC), although the recurrence of AF after successful DCC is common. We examined whether transesophageal echocardiography (TEE)-guided early DCC, compared with the conventional approach of DCC after 3 weeks of anticoagulation with dabigatran-etexilat, reduces the recurrence of AF. A total of 126 consecutive patients with persistent AF were randomly assigned to a TEE followed by early DCC (n = 65) or to a conventional treatment with dabigatran-etexilat for 3 weeks followed by DCC (n = 61). None of the patients received any antiarrhythmic treatment other than ß blockers, and all the DCCs were successful. Forty-eight-hour Holter monitoring was performed at 28 days and at 3, 6, and 12 months after the DCC. The primary outcome was AF recurrence lasting ≥30 seconds. The analysis was stratified by AF duration <60 (n = 62) or >60 days (n = 64) before DCC. We observed a significant reduction in the AF recurrence risk (p = 0.003) in patients with persistent AF <60 days who received early DCC, but there was no significant benefit of early DCC (p = 0.456) in patients with persistent AF lasting >60 days. The recurrence-free survival probability at 28 days in patients with persistent AF <60 days was 0.27 (95% confidence interval 0.14 to 0.51) in the conventional treatment group compared with 0.69 (95% confidence interval 0.54 to 0.87; p = 0.006) in the early DCC group. A benefit of early DCC persisted throughout 12 months of follow-up. In conclusion, TEE-guided early DCC in patients with persistent AF <60 days results in a significant reduction of AF recurrence.

Automatic Real-Time Embedded QRS Complex Detection for a Novel Patch-Type Electrocardiogram Recorder.

Cardiovascular diseases are projected to remain the single leading cause of death globally. Timely diagnosis and treatment of these diseases are crucial to prevent death and dangerous complications. One of the important tools in early diagnosis of arrhythmias is analysis of electrocardiograms (ECGs) obtained from ambulatory long-term recordings. The design of novel patch-type ECG recorders has increased the accessibility of these long-term recordings. In many applications, it is furthermore an advantage for these devices that the recorded ECGs can be analyzed automatically in real time. The purpose of this study was therefore to design a novel algorithm for automatic heart beat detection, and embed the algorithm in the CE marked ePatch heart monitor. The algorithm is based on a novel cascade of computationally efficient filters, optimized adaptive thresholding, and a refined search back mechanism. The design and optimization of the algorithm was performed on two different databases: The MIT-BIH arrhythmia database ([Formula: see text]%, [Formula: see text]) and a private ePatch training database ([Formula: see text]%, [Formula: see text]%). The offline validation was conducted on the European ST-T database ([Formula: see text]%, [Formula: see text]%). Finally, a double-blinded validation of the embedded algorithm was conducted on a private ePatch validation database ([Formula: see text]%, [Formula: see text]%). The algorithm was thus validated with high clinical performance on more than 300 ECG records from 189 different subjects with a high number of different abnormal beat morphologies. This demonstrates the strengths of the algorithm, and the potential for this embedded algorithm to improve the possibilities of early diagnosis and treatment of cardiovascular diseases.

Different pH-dependencies of the two synaptic adhesion molecules N-cadherin and cadherin-11 and the possible functional implication for long-term potentiation.

Ca(2+) -dependent adhesion molecules, cadherins, localised at synaptic sites are critically involved in long-term potentiation (LTP). N-cadherin is thought to promote LTP whereas cadherin-11 seems to counteract LTP. Since high synaptic activity is accompanied by local transient changes of the pH in the synaptic cleft, we studied whether the binding activity of cadherins is dependent on the pH and whether this might play a role during LTP. By atomic force microscopy (AFM) and laser tweezer experiments, we could show on the single molecule level as well as in a cell-based system that a decrease of the pH from 7.4 to 7.0 will result in a significant weakening of N-cadherin binding activity but in an increase of cadherin-11 binding. These differences in the pH dependencies of both molecules could be one explanation for their opposing roles during LTP. High-frequency stimulation will lead to a local acidosis in the synaptic cleft resulting in weakening of N-cadherin-mediated adhesion facilitating synaptic remodeling and LTP induction, whereas cadherin-11 bonds will be strengthened counteracting synaptic remodeling and LTP generation.