Raoul Pop

Surgical management of spinal dural arteriovenous fistulas.

Spinal dural arteriovenous fistulas are the most common type of spinal arteriovenous malformations. Treatment options consist of microsurgical exclusion and/or endovascular embolization. We retrospectively identified all patients who benefited from surgical treatment at our tertiary center between January 2001 and December 2008. Clinical and imaging data were collected from patient files, including pre- and post-operative formal neurological examination, complete spine MRI and spinal digital subtraction angiography. Of our 30 patients, 25 were men and five were women with a median age of 62 years (range 24-76). The average delay between symptom onset and clinical diagnosis was 27 months (range 1-90). Complete cure of the fistula was obtained in all patients in a single surgical session with no procedural complications and no surgical morbidity. After a mean follow-up period of 32 months (range 14-128), 25 patients (83%) had improved, four were stable and one worsened. Despite recent advances in endovascular techniques and materials, there is a subgroup of patients for which surgery remains the best treatment option. Careful patient selection, a multidisciplinary approach and standardized surgical techniques can lead to excellent results with virtually no complications.

Stroke Mimics in a Stroke Care Pathway Based on MRI Screening.

Background: Since the use of tissue plasminogen activator for acute ischemic stroke (IS), stroke care pathways have been developed for patients with suspicion of acute stroke. The aim of this prospective observational study was to analyze the stroke mimic (SM) characteristics in patients who were part of our stroke care pathway. Methods: All consecutive patients admitted in the code stroke within a 1-year period were prospectively enrolled in this study. Patients with a sudden onset of neurological focal deficit in a time window less than 4H30 as indicated for intravenous thrombolysis, had been accepted in the pathway by a neurologist who was directly contactable by the prehospital emergency medical service 24 h per day. Patients arrived directly on the MRI site without passing by the emergency department. A clinical neurological evaluation and a brain MRI with tri-dimensional time-of-flight magnetic resonance angiography were performed. The FAST score was calculated a posteriori. The final discharge diagnosis was concluded either immediately after both neurological examination and cerebrovascular neuroimaging or after other relevant investigations. We classified the discharge diagnosis into neurovascular diseases (NVDs) and into SM. Results: There were 1,361 consecutive patients admitted for suspicion of acute stroke. Sixty-two percent (n = 840) had an NVD including IS (n = 529), transient ischemic attacks (n = 236), intracranial hemorrhages (n = 68), cerebral venous thrombosis (n = 3) and neurovascular medullar pathologies (n = 4). SM represented 38% of cases (n = 521) and the most frequent discharge diagnosis was defined as headaches (18.6%), psychological disorders (16.7%), peripheral vertigo (11.9%) and epilepsy (10.6%). The comparison between the characteristics of the NVD and those of the SM groups showed some significant differences: in the SM group, women were more represented, patients were younger and the NIHSS was lower than in the NVD group. All cardiovascular risk factors were more represented in the NVD group. Concerning the symptoms, motor deficit, speech disturbances, homonymous lateral hemianopia and head and gaze deviation were more represented in the NVD group, whereas vertigo, non-systematized visual trouble, headache, confusion, weakness, neuropsychological symptoms, seizure and chest pain were significantly more frequent in the SM group. The negative predictive value of the FAST score was 64% and the positive predictive value was 76%. Conclusions: A rate of SM up to 38% of the code stroke system confirms the difficulty to distinguish clinically a stroke from another diagnosis. In this study, using cerebral MRI in first intention was of special interest in patients with acute neurological symptoms to differentiate an NVD from an SM.

Gastric supply manipulation to modulate ghrelin production and enhance vascularization to the cardia: proof of the concept in a porcine model.

Introduction. Selective embolization of the left-gastric artery (LGA) reduces levels of ghrelin and achieves significant short-term weight loss. However, embolization of the LGA would prevent the performance of bariatric procedures because the high-risk leakage area (gastroesophageal junction [GEJ]) would be devascularized. Aim. To assess an alternative vascular approach to the modulation of ghrelin levels and generate a blood flow manipulation, consequently increasing the vascular supply to the GEJ. Materials and methods. A total of 6 pigs underwent a laparoscopic clipping of the left gastroepiploic artery. Preoperative and postoperative CT angiographies were performed. Ghrelin levels were assessed perioperatively and then once per week for 3 weeks. Reactive oxygen species (ROS; expressed as ROS/mg of dry weight [DW]), mitochondria respiratory rate, and capillary lactates were assessed before and 1 hour after clipping (T0 and T1) and after 3 weeks of survival (T2), on seromuscular biopsies. A celiac trunk angiography was performed at 3 weeks. Results. Mean (±standard deviation) ghrelin levels were significantly reduced 1 hour after clipping (1902 ± 307.8 pg/mL vs 1084 ± 680.0; P = .04) and at 3 weeks (954.5 ± 473.2 pg/mL; P = .01). Mean ROS levels were statistically significantly decreased at the cardia at T2 when compared with T0 (0.018 ± 0.006 mg/DW vs 0.02957 ± 0.0096 mg/DW; P = .01) and T1 (0.0376 ± 0.008mg/DW; P = .007). Capillary lactates were significantly decreased after 3 weeks, and the mitochondria respiratory rate remained constant over time at the cardia and pylorus, showing significant regional differences. Conclusions. Manipulation of the gastric flow targeting the gastroepiploic arcade induces ghrelin reduction. An endovascular approach is currently under evaluation.

Flow control using ScepterTM balloons for Onyx embolization of a vein of Galen aneurysmal malformation

PurposeWe present a technical development of the endovascular treatment technique for vein of Galen aneurysmal malformation, using Onyx™ (ethylene vinyl alcohol copolymer) delivered under flow control through double-lumen balloon microcatheters.Materials and methodsAn 11-month-old patient that initially presented with increasing head circumference was diagnosed with mural type vein of Galen aneurysmal malformation. Complete cure was obtained in a single endovascular treatment session. Onyx was delivered simultaneously through two double-lumen balloon microcatheters (Scepter™, Microvention, Terumo Group). In both arterial feeders, balloon inflation occluded the high-flow arterial-venous shunting and thus facilitated the controlled propagation of the embolic product in the afferent artery and the shunt point while preventing distal migration into the venous system.ResultsTwo years post-procedure, MR imaging showed persistent occlusion of arterial-venous shunts with complete regression of the venous dilatation. On clinical examination, the patient had no neurological deficits, and no cognitive impairment was detected at neuropsychological testing.ConclusionThe use of double-lumen balloon microcatheters for flow control during delivery of Onyx represents a viable alternative for the endovascular treatment of vein of Galen aneurysmal malformations.

Linearly chirped fiber Bragg grating response to thermal gradient: from bench tests to the real-time assessment during in vivo laser ablations of biological tissue

Abstract. The response of a fiber optic sensor [linearly chirped fiber Bragg grating (LCFBG)] to a linear thermal gradient applied on its sensing length (i.e., 1.5 cm) has been investigated. After these bench tests, we assessed their feasibility for temperature monitoring during thermal tumor treatment. In particular, we performed experiments during ex vivo laser ablation (LA) in pig liver and in vivo thermal ablation in animal models (pigs). We investigated the following: (i) the relationship between the full width at half maximum of the LCFBG spectrum and the temperature difference among the extremities of the LCFBG and (ii) the relationship between the mean spectrum wavelength and the mean temperature acting on the LCFBG sensing area. These relationships showed a linear trend during both bench tests and LA in animal models. Thermal sensitivity was significant although different values were found with regards to bench tests and animal experiments. The linear trend and significant sensitivity allow hypothesizing a future use of this kind of sensor to monitor both temperature gradient and mean temperature within a tissue undergoing thermal treatment.

Risk of Deep vein thrombosis in neurosurgery: State of the art on prophylaxis protocols and best clinical practices

OBJECTIVE To analytically discuss some protocols in Deep vein thrombosis (DVT)/pulmonary Embolism (PE) prophylaxis currently use in Neurosurgical Departments around the world. DATA SOURCES Analysis of the prophylaxis protocols in the English literature: An analytical and narrative review of literature concerning DVT prophylaxis protocols in Neurosurgery have been conducted by a PubMed search (back to 1978). DATA EXTRACTION 80 abstracts were reviewed, and 74 articles were extracted. DATA ANALYSIS The majority of DVT seems to develop within the first week after a neurosurgical procedure, and a linear correlation between the duration of surgery and DVT occurrence has been highlighted. The incidence of DVT seems greater for cranial (7.7%) than spinal procedures (1.5%). Although intermittent pneumatic compression (IPC) devices provided adequate reduction of DVT/PE in some cranial and combined cranial/spinal series, low-dose subcutaneous unfractionated heparin (UFH) or low molecular-weight heparin (LMWH) further reduced the incidence, not always of DVT, but of PE. Nevertheless, low-dose heparin-based prophylaxis in cranial and spinal series risks minor and major postoperative haemorrhages: 2-4% in cranial series, 3.4% minor and 3.4% major haemorrhages in combined cranial/spinal series, and a 0.7% incidence of major/minor haemorrhages in spinal series. CONCLUSION This analysis showed that currently most of the articles are represented by case series and case reports. As long as clear guidelines will not be defined and universally applied to this diverse group of patients, any prophylaxis for DVT and PE should be tailored to the individual patient with cautious assessment of benefits versus risks.

Foramen magnum dural arteriovenous fistula presenting with epilepsy.

Intracranial dural arteriovenous fistulas (dAVFs) with perimedullary drainage represent a rare subtype of intracranial dAVF. Patients usually experience slowly progressive ascending myelopathy and/or lower brainstem signs. We present a case of foramen magnum dural arteriovenous fistula with an atypical clinical presentation. The patient initially presented with a generalised tonic-clonic seizure and no signs of myelopathy, followed one month later by rapidly progressive tetraplegia and respiratory insufficiency. The venous drainage of the fistula was directed both to the left temporal lobe and to the perimedullary veins (type III + V), causing venous congestion and oedema in these areas and explaining this unusual combination of symptoms. Rotational angiography and overlays with magnetic resonance imaging volumes were helpful in delineating the complex anatomy of the fistula. After endovascular embolisation, there was complete remission of venous congestion on imaging and significant clinical improvement. To our knowledge, this is the first report of a craniocervical junction fistula presenting with epilepsy.

Aneurysmal wall imaging in a case of cortical superficial siderosis and multiple unruptured aneurysms

We report a case of interhemispheric and bifrontal cortical superficial siderosis in association with two intracranial aneurysms. The patient had no clinical history suggestive of aneurysm rupture, no feature of amyloid angiopathy or other apparent etiology for cortical siderosis. We performed high resolution brain MRI with dark blood T1 sequences before and after IV contrast injection. An anterior communicating aneurysm showed partial wall enhancement on the posterior wall whereas a left posterior communicating aneurysm did not. In the light of recent reports of the association of wall enhancement with unstable aneurysms, we considered wall enhancement to be a marker of inflammation and remodeling of the aneurysm wall, resulting in chronic hemorrhagic suffusion in the subarachnoid spaces. To our knowledge, this is the first report offering proof for a possible link between apparently unruptured aneurysms and cortical siderosis.

Balloon protection of the Labbé vein during transarterial embolization of a dural arterio-venous fistula.

Introduction Endovascular treatment of type III dural arterio-venous fistulas can be challenging if the fistulous point is close to a functionally important cortical vein. Methods A technique is described for temporary balloon protection of the vein of Labbé during transarterial Onyx embolization of a type III dural arterio-venous fistula. One illustrative case is presented. Careful anatomic consideration of the concerned venous segment (at the insertion point into the lateral sinus) and the choice of balloon minimized the risk of venous rupture. Results Using this method, satisfactory progression of Onyx was obtained within the arterio-venous shunt while preserving the patency of the Labbé vein. Conclusion Temporary balloon protection of the Labbé vein is a feasible option to preserve its patency during embolization of dural arterio-venous fistulas. To the authors’ knowledge, this is the first report on the use of temporary balloon protection of a cortical vein.

Evolution of Prophylaxis Protocols for Venous Thromboembolism in Neurosurgery: Results from a Prospective Comparative Study on Low-Molecular-Weight Heparin, Elastic Stockings, and Intermittent Pneumatic Compression Devices

BACKGROUND The incidence of venous thromboembolism (VT) in neurosurgical practice is astonishingly high, representing a major cause of morbidity and mortality. Prophylaxis strategies include elastic stockings, low-molecular-weight heparin (LMWH), and intermittent pneumatic compression (IPC) devices. OBJECTIVE To assess the safety and efficacy of 2 different VT prophylaxis protocols implemented in a European neurosurgical center. METHODS All patients admitted for neurosurgical intervention between 2012 and 2016 were stratified as low, moderate, and high risk of VT and received a combination of elastic stockings and LMWH. The protocol was modified in 2014 with the inclusion of perioperative IPC devices for all patients and only in the high-risk group also postoperatively. RESULTS At time of post-hoc analysis, data obtained from patients included in this study before 2014 (Protocol A, 3169 patients) were compared with those obtained after the introduction of IPC (Protocol B, 3818 patients). Among patients assigned to protocol A, 73 (2.3%) developed deep-vein thrombosis (DVT) and 28 (0.9%) developed pulmonary embolism (PE), 9 of which were fatal (0.3%). Among patients assigned to protocol B, 32 developed DVT (0.8%) and 7 (0.18%) developed PE, with 2 eventually resulting in the death of the patient. A post-hoc analysis confirmed that the use of preoperative LMWH was not associated with a statistically significant greater risk of postoperative bleeding. CONCLUSIONS This study, despite its limitations of the nonrandomized design, seems to suggest that perioperative IPC devices are a non-negligible support in the prophylaxis of clinically symptomatic DVT and PE.