When Is Diagnostic Subtraction Angiography Indicated Before Clipping of Unruptured and Ruptured Intracranial Aneurysms? An International Survey of Current Practice.

INTRODUCTION: The goal of this survey is to investigate the indications for preoperative digital subtraction angiography (DSA) before clipping of ruptured and unruptured intracranial aneurysms in an international panel of neurovascular specialists. METHODS: An anonymous survey of 23 multiple-choice questions relating to indications for DSA before clipping of an intracranial aneurysm was distributed to the international panel of attendees of the European-Japanese Cerebrovascular Congress (EJCVC), which took place in Milan, Italy on 7-9 June 2018. The survey was collected during the same conference. Descriptive statistics were used to analyze the data. RESULTS: A total of 93 surveys were distributed, and 67 (72%) completed surveys were returned by responders from 13 different countries. Eighty-five percent of all responders were neurosurgeons. For unruptured and ruptured middle cerebral artery (MCA) aneurysms without life-threatening hematoma, approximately 60% of responders perform surgery without preoperative DSA. For aneurysms in other locations than MCA, microsurgery is done without preoperative DSA in 68% of unruptured and in 73% of ruptured cases. In cases of ruptured MCA or ruptured non-MCA aneurysms with life-threatening hematoma, surgery is performed without DSA in 97% and 96% of patients, respectively. Factors which lead to preoperative DSA being performed were: aneurysmal shape (fusiform, dissecting), etiology (infectious), size (>25 mm), possible presence of perforators or efferent vessels arising from the aneurysm, intra-aneurysmal thrombus, previous treatment, location (posterior circulation and paraclinoid aneurysm) and flow-replacement bypass contemplated for final aneurysm treatment. These are all factors that qualify an aneurysm as a complex aneurysm. CONCLUSION: There is still a high variability in the surgeons' preoperative workup regarding the indication for DSA before clipping of ruptured and unruptured intracranial aneurysms, except for ruptured aneurysms with life-threatening hematoma. There is a general consensus among cerebrovascular specialists that any angioanatomical feature indicating a complex aneurysm should lead to a more detailed workup including preoperative DSA.

Follow-up neuroimaging after non-perimesencephalic, angiogram-negative subarachnoid hemorrhage.

BACKGROUND: In approximately 15% of spontaneous subarachnoid hemorrhage (SAH) patients, no bleeding source is found in the initial imaging. These patients can be categorized as either perimesencephalic (PM-SAH) or non-perimesencephalic (NP-SAH) subarachnoid hemorrhage patients. Follow-up imaging is routinely performed after NP-SAH to detect treatable etiologies; however, the optimal follow-up imaging protocol remains unclear. This study examines the optimal time interval to re-imaging and the performance of magnetic resonance imaging and angiography (MRI/A) in this setting. METHODS: In this retrospective study, the records of NP-SAH patients treated at the University Hospital of Zurich (Switzerland) from 2005 to 2018 were analyzed. Clinical and radiological data were collected. Re-imaging data was grouped according to imaging modality and divided into three time-categories after bleeding: short-term (<2 weeks), medium-term (2-8 weeks) and long-term (>8 weeks) re-imaging. RESULTS: Eighty-one NP-SAH patients were included. In 8 patients an aneurysm was diagnosed during re-imaging via digital subtraction angiography (9.9% diagnostic yield). Five aneurysms were detected at short-term in 81 patients (6.2% short-term yield) and three at medium-term re-imaging in 27 patients (11.1% medium-term yield). No aneurysms were found after 8 weeks in 56 patients. Five of these 8 patients also received MRI/A re-imaging, which was able to show the aneurysm in all 5 cases. CONCLUSIONS: Our study emphasizes the importance of re-imaging in NP-SAH patients, which should be done both at short-term and at medium-term follow-up after the hemorrhage. Long-term re-imaging after 8 weeks might not be of diagnostic benefit. MRI/A might be considered as a possible noninvasive re-imaging modality in this setting.

Topographic brain tumor anatomy drives seizure risk and enables machine learning based prediction.

OBJECTIVE: The aim of this study was to identify relevant risk factors for epileptic seizures upon initial diagnosis of a brain tumor and to develop and validate a machine learning based prediction to allow for a tailored risk-based antiepileptic therapy. METHODS: Clinical, electrophysiological and high-resolution imaging data was obtained from a consecutive cohort of 1051 patients with newly diagnosed brain tumors. Factor-associated seizure risk difference allowed to determine the relevance of specific topographic, demographic and histopathologic variables available at the time of diagnosis for seizure risk. The data was divided in a 70/30 ratio into a training and test set. Different machine learning based predictive models were evaluated before a generalized additive model (GAM) was selected considering its traceability while maintaining high performance. Based on a clinical stratification of the risk factors, three different GAM were trained and internally validated. RESULTS: A total of 923 patients had full data and were included. Specific topographic anatomical patterns that drive seizure risk could be identified. The involvement of allopallial, mesopallial or primary motor/somatosensory neopallial structures by brain tumors results in a significant and clinically relevant increase in seizure risk. While topographic input was most relevant for the GAM, the best prediction was achieved by a combination of topographic, demographic and histopathologic information (Validation: AUC: 0.79, Accuracy: 0.72, Sensitivity: 0.81, Specificity: 0.66). CONCLUSIONS: This study identifies specific phylogenetic anatomical patterns as epileptic drivers. A GAM allowed the prediction of seizure risk using topographic, demographic and histopathologic data achieving fair performance while maintaining transparency.

The PTZ kindling mouse model of epilepsy exhibits exploratory drive deficits and aberrant activity amongst VTA dopamine neurons in both familiar and novel space.

Recurrent seizures that define epilepsy are often accompanied by psychosocial problems and cognitive deficits with incompletely understood aetiology. We therefore used the pentylenetetrazol (PTZ) kindling model of epilepsy in mice to examine potential seizure-associated neuropathologies, focusing on motivation, memory and novel-environment-induced activation of midbrain dopaminergic neurons. In addition to recurrent seizures, we found that PTZ kindling led to a strong suppression of novelty-driven exploration while largely sparing fear-driven exploration. The deficits in exploratory drive may be relevant for other cognitive impairments since reduced unassisted rearing in a learning arena correlated with poorer spatial memory of object location. Using c-Fos immunofluorescence as a marker of neuronal activity, we observed that dopamine neurons within the ventral tegmental area (VTA) of PTZ kindled mice demonstrate hyperactivity at baseline and hypoactivity in response to a novel environment compared to saline-injected cagemate controls. These data extend previous findings of PTZ kindling-mediated disruptions of hippocampal processes important for novel environment recognition and learning by demonstrating PTZ kindling also induces motivational deficits that are associated with reduced stimulus-evoked activation of VTA dopamine neurons. More broadly, these data help understand the aetiology of complex behavioural changes in the PTZ kindling model, and may assist in the development of superior diagnoses and treatments for epilepsy.

Laparoscopic robotic-assisted gastrointestinal surgery: the Geneva experience.

The continuing development of robotic surgery supports its use in laparoscopic gastrointestinal surgery. Our study retrospectively reviewed the surgical outcome and patient's satisfaction of gastrointestinal laparoscopic robotic procedures. From January 2003 to September 2007, 94 patients (27 women, 67 men) with a mean age of 53 years (range 19-84 years) underwent laparoscopic surgery with a da Vinci robotic system. There were 40 colorectal cases (43%), 31 anti-reflux surgery cases (33%) and 14 obesity surgery cases (15%); the remaining cases consisted of gastric and gallbladder surgery, intra-abdominal tumour excisions, and hepatic cyst resections. The majority of the cases (88, 94%) were performed for benign disease. The mean operative time was 153 min (range 60-330 min). One patient needed a blood transfusion. The mean body mass index was 25 (range 16-47). No death occurred. Five cases (5.3%) were converted to conventional laparoscopic surgery (n = 3) or to laparotomy (n = 2). Morbidity consisted of one Nissen redo surgery to loosen a tight anti-reflux valve 6 days after robotic surgery, a robotic left ureter repair and pelvic haemorrhage following proctectomy requiring re-operation to control haemostasis and to remove pelvic haematoma. Mean follow-up time was 11 months (range 15 days to 34 months). One case of incisional trocar hernia needed re-operation. Overall patient's satisfaction was high: few scars were cheloïd, while functional surgical outcome was rated high by most of the patients. Our preliminary experience was encouraging, with minimal morbidity and very high acceptance by patients.