Anatomy of the greater occipital nerve: implications in posterior fossa approaches.

PURPOSE: Because of its superficial location in the dorsal regions of the scalp, the greater occipital nerve (GON) can be injured during neurosurgical procedures, resulting in post-operative pain and postural disturbances. The aim of this work is to specify the course of the GON and how its injuries can be avoided while performing posterior fossa approaches. METHODS: This study was carried out at the department of anatomy at Bordeaux University. 4 specimens were dissected to study the GON course. Posterior fossa approaches (midline suboccipital, paramedian suboccipital, retrosigmoid and petrosal) were performed on 4 other specimens to assess potential risks of GON injuries. RESULTS: The GON runs around the obliquus capitis inferior (100%), crosses the semispinalis capitis (100%) and the trapezius (75%) or its aponeurosis (25%). Direct GON injuries can be seen in paramedian suboccipital approaches. Stretching of the GON can occur in midline suboccipital and paramedian suboccipital approaches. We found no evidence of direct or indirect GON injury in retrosigmoid or petrosal approaches. CONCLUSION: Our study provides interesting data regarding the risk GON injury in posterior fossa approaches. Direct GON injuries in paramedian suboccipital approaches can be avoided with careful dissection. Placing retractors in contact with the periosteum and performing a minimal retraction may help to avoid excessive GON stretching in midline suboccipital and paramedian suboccipital approaches. Furthermore, the incision for retrosigmoid approaches should be as lateral as possible and not too caudal. Finally, avoiding extreme patient positioning reduces the risk of GON stretching in all approaches.

WHO grade II meningioma: Epidemiology, survival and contribution of postoperative radiotherapy in a multicenter cohort of 88 patients.

BACKGROUND: Meningioma is the most common primary intracranial tumor, representing 13-36.6% of all primary central nervous system tumors. Meningiomas are benign in about 90% of cases. World Health Organization (WHO) grade II meningioma is associated with a high rate of recurrence and poorer survival than in grade I. The reference treatment is surgery, which should be as complete as possible. Currently, in grade II, there are no recommendations for systematic adjuvant treatment such as radiotherapy. We studied a homogeneous series of grade II meningiomas treated by surgery in two university hospital centers to analyze use of radiotherapy and its efficacy. METHODS: We retrospectively analyzed patients in our database with WHO grade II meningioma, operated on between 2007 and 2010 in the university hospitals of Montpellier and Bordeaux, France. Clinical and radiological data, treatments and survival were analyzed. RESULTS: Eighty-eight patients were included. Five-year overall survival was 89.7%. Nineteen patients received radiotherapy during follow-up, without significant impact on survival (P=0.27). CONCLUSION: In WHO grade II meningioma, it is currently difficult to establish clear recommendations for radiotherapy. The present study is in accordance with the literature that early postoperative radiotherapy is not mandatory in grade II meningioma with macroscopically total resection.

Functional outcome 1 year after aneurysmal subarachnoid hemorrhage due to ruptured intracranial aneurysm in elderly patients.

BACKGROUND: Population aging raises questions about extending treatment indications in elderly patients with aneurysmal subarachnoid hemorrhage (aSAH). We therefore assessed functional status 1 year after treatment. METHODS: This study involved 310 patients, aged over 70 years, with ruptured brain aneurysm, enrolled between 2008 and 2014 in a prospective multicentre trial (FASHE study: NCT00692744) but considered unsuitable for randomisation and therefore analysed in the observational arms of the study: endovascular occlusion (EV), microsurgical exclusion (MS) and conservative treatment. The aims were to assess independence, cognition, autonomy and quality of life (QOL) at 1 year post-treatment, using questionnaires (MMSE, ADLI, IADL, EORTC-QLQ-C30) filled in by independent nurses after discharge. RESULTS: The 310 patients received the following treatments: 208 underwent EV (67.1%), 54 MS (17.4%) and 48 were conservatively managed (15.5%). At 1 year, independence rates for patients admitted with good clinical status (WFNS I-III) were, according to the aneurysm exclusion procedure (EV, MS or conservative), 58.9%, 50% and 12.1% respectively. MMSE score was pathological in 26 of the 112 EV patients (23.2%), 10 of the 25 MS patients (40%) and 4 of the 9 patients treated conservatively (44%), without any statistically significant difference [Pearson's Chi2 test, F ratio=4.29; P=0.11]. Regarding QoL, overall score was similar between the EV and MS cohorts, but significantly lower with conservative treatment. CONCLUSION: Elderly patients in good clinical condition with aSAH should be treated regardless of associated comorbidities. Curative treatment (EV or MS) reduced mortality without increasing dependence, in comparison with conservative treatment.

[Educational assessment of the first computerized national ranking exam in France in 2016: Opportunities for improvement]. / Analyse docimologique des premières Épreuves classantes nationales informatisées (ECNi) de 2016 : propositions d'amélioration.

In June 2016, 8124 medical students in their sixth year of graduation passed the first computerized national ranking exam (CNRE) in France after which they will have to choose what medical specialty they will be practicing all their life. We conducted the first educational assessment of this CNRE according to two criteria: the relevance of the questions and the cognitive domain mainly required to answer these questions. We propose two improvements for the future CNRE: promote student reasoning in the multiple choices questions, reduce to 10 the number of multiple choice questions in the progressive clinical cases and increase by 9 their total number (from 18 to 27), and use a majority of mini-clinical cases for isolated multiple choice questions in order to focus students on reasoning instead of simple knowledge restitution.

Peritumoral edema and prognosis in intracranial meningioma surgery.

Peritumoral brain edema (PTBE) is often associated with meningiomas. PTBE is probably implicated in the complications occurring in intracranial meningiomas. The goal of this study was to determine the exact implication of PTBE in prognosis. Thirty consecutive patients who underwent surgery for intracranial meningiomas were investigated over a 1-year period. We focused on the clinical and radiological status before and after surgery, and postoperative complications. Multiple regression analysis revealed a close correlation (p<0.05) between PTBE and symptoms, type of arterial supply, difficulty of surgical removal, and postoperative complications. PTBE is likely implicated in the morbidity of intracranial meningiomas. We suggest predictive factors for difficult surgical resection, and emphasise the importance of medical preoperative management and post-operative follow-up.

Junction between the great cerebral vein and the straight sinus: an anatomical, immunohistochemical, and ultrastructural study on 25 human brain cadaveric dissections.

The cerebral venous system is poorly understood, and best appreciated under macroscopic anatomical considerations. We present an anatomical and immunohistochemical studies to better define the morphological characteristics of the junction between the great cerebral vein and the straight sinus. Twenty-five cadaveric specimens from the anatomy laboratory of the University Victor Segalen of Bordeaux were studied. The observation of the venous junctions with the straight sinus was performed under an operating microscope. The smooth muscular actin immunohistochemical staining was performed for 18 veno-sinosal junctions. Five venous junctions were observed using an electron microscope. We observed 3 different anatomic aspects: type 1 was a junction with a small elevation in its floor and a posterior thickening (14 cases); type 2 was a junction with an outgrowth on the floor like a cornice (7 cases); and type 3 was a junction presenting a nodule. Microscopic study of type 1 and 2 junctions showed a positive coloration to orceine attesting the presence of elastic fibers. Immunohistochemistry revealed the presence of smooth muscular actin and S 100 protein attesting the presence of smooth muscular fibers and nervous fibers. We observed in the ultrastructural study, a morphological progression of the endothelium. The venous orifice of the great cerebral vein into the straight sinus could be anatomically assimilated as a true "sphincter." Its function in the regulation of the cerebral blood flow needs further exploration.

A randomized controlled study assessing outcome, cognition, autonomy and quality of life in over 70-year-old patients after aneurysmal subarachnoid hemorrhage.

BACKGROUND: Current aging of the population with good physiological status and the increasing incidence of subarachnoid hemorrhage (SAH) in elderly patients has enhanced the benefit of treatment in terms of independence and long-term quality of life (QoL). METHODS: From November 1, 2008 to October 30, 2012, 351 patients aged 70 years or older with aneurysmal SAH underwent adapted treatment: endovascular coiling (EV) for 228 (65%) patients, microsurgical clipping (MS) for 75 (29.3%) or conservative treatment for 48 (13.7%). Forty-one of these were randomized to EV (n=20) or to MS (n=21). The objectives were to determine the proportion of patients with modified Rankin Scale score≤2 (independence) at 1 year, and, secondarily, to compare cognitive function on the Mini-Mental State Examination (MMSE), autonomy on the Activities of Daily Living Index (ADLI) and Instrumental Activities of Daily Living scale (IADL), and QoL, in the prospective and randomized arms, at 1 year. RESULTS: At 1 year, with 1 loss to follow-up in the EV arm, 11 patients (55%) were independent after EV occlusion and 8 (38.1%) after MS exclusion, without significant difference (P=0.29). Mortality was higher after MS during the first 2 postoperative months, and thereafter the difference between MS and EV ceased to be significant. Cognitive function and autonomy scores were similar in both arms. CONCLUSION: In elderly patients treated for aneurysmal SAH, approximately 50% were independent at 1 year, with conserved cognition and autonomy. EV and MS are valid procedures in this population, with similar results at 1 year in terms of independence, cognition, autonomy, and QoL.

Dorsal rhizotomy combined with anterior sacral root stimulation for neurogenic bladder.

A spinal cord lesion (traumatic or not) above the sacral micturition center may induce hyperreflexia of the detrusor, spasticity of the sphincter and vesico-sphincter dyssynergia. Eventually, alterations in the upper urinary tract can be associated with increased mortality in this patient population. Sacral rhizotomies combined with implantation of an anterior sacral root stimulator appear to be an effective method not only for the treatment of voiding dysfunction but also for defecation and sexual disorders. The clinical and electrophysiological checks and the surgical technique are described. In most series, the results show a constant improvement in the patient's functional status. Ninety percent of patients gain satisfactory continence and no longer require an incontinence appliance. Bladder capacity and compliance increase dramatically. As a consequence, urinary infection rate decreases. The majority of patients remain dry, and more than 80% have a complete voiding or a post-void residue of less than 50ml and do not require any catheterization. Anterior sacral root stimulation combined with sacral posterior rhizotomy is a valuable method to restore bladder function in spinal cord-injured patients suffering from hyperactive bladder.

Sacral neuromodulation as a functional treatment of bladder overactivity.

Sacral neuromodulation, namely the electrical stimulation of the sacral nerves has become an alternative treatment for cases of idiopathic bladder overactivity. The mechanism of action in this type of spinal cord modulation is only partially understood but it seems to involve stimulation of inhibitory interneurons. Temporary sacral nerve stimulation is the first step. It consists of the temporary application of neurostimulation as a diagnostic test in order to check the integrity of the sacral root and determine the best location for the implant. If the test stimulation is successful, a permanent device is implanted. In experienced hands, this is a safe procedure. When the patients are selected on the basis of sound criteria, more than three-quarters of them show a clinically significant improvement with a reduction in the frequency of incontinence episodes by more than 50%; however, the results vary according to each author's method of evaluation. The application of this technique should be combined with careful follow-up and attentive adjustments of the stimulation parameters in order to optimize the coordination of activity between the neurological systems involved.

In vitro efficacy of three lazaroids in a model of acute chemical neuronal hypoxia.

Free radicals are highly reactive chemicals containing an unpaired electron and are normally produced by the cellular metabolism. But the excessive production of free radicals by oxidative stress is engaged in a large variety of diseases. The goal of this work was to determine the neuroprotective effect of free radical scavengers in an acute in vitro model of neuronal hypoxia. Primary cultures of cortical neurons of rats were exposed to 0.5 mM sodium cyanide for 6 h. Neuron death was evaluated with a lactate dehydrogenase assay. This mortality was up to 66.5% in cultures exposed to 0.5 mM sodium cyanide compared to non-exposed control cultures. Three lazaroids (U-74500A, U-74389G, U-83836E), were added to cultures, at different concentrations (10(-7)-10(-5) M), simultaneously with cyanide, during 6h. These agents caused a reduction in neuronal death, compared to exposed cultures. Efficacy varied with lazaroid compounds and U-74500A decreased neuronal death to 37-23.5%, U-74389G to 37-32%, and U-83836E to 42-33%. These results suggest a partial neuroprotective effect of free radical scavengers since lipid peroxidation is a key cellular event in neuronal injury, and its inhibition with lazaroids could help to reduce brain ischaemic lesions.

Sacral neuromodulation in lower urinary tract dysfunction.

Vesico-urethral dysfunction is a major problem in daily medical practice due to its psychological disturbances, its social costs and its high impact on quality of life. Recently, sacral neuromodulation, namely the electrical stimulation of the sacral nerves, appears to have become an alternative for radical bladder surgery particularly in cases of idiopathic bladder overactivity. The mechanism of action is only partially understood but it seems to involve a modulation in the spinal cord due to stimulation of inhibitory interneurons. Temporary sacral nerve stimulation is the first step. It comprises the temporary application of neuromodulation as a diagnostic test to determine the best location for the implant and to control the integrity of the sacral root. If test stimulation is successful, a permanent device is implanted. This procedure is safe in experienced hands. So-called idiopathic bladder overactivity still the major indication for this technique. Patients not likely to benefit from the procedure were those with complete or almost complete spinal lesions, but incomplete spinal lesions seemed to be a potential indication. This technique is now also indicated in the case of idiopathic chronic retention and chronic pelvic pain syndrome. When selection is performed, more than three-quarters of the patients showed a clinically significant response with 50% or more reduction in the frequency of incontinent episodes, but the results vary according to the author's mode of evaluation. From the economic point of view, the initial investment in the device is amortized in the mid-term by savings related to lower urinary tract dysfunction. Finally, this technique requires an attentive follow-up and adjustments to the electric parameters so as to optimize the equilibrium between the neurological systems.

Vertebral artery (V2) pseudo-aneurysm after surgery for cervical schwannoma. How to prevent it and a review of the literature.

STUDY DESIGN: Case report and review of the literature. OBJECTIVE: To prevent and manage a suspected iatrogenic vertebral artery injury during a cervical spine anterior approach. SUMMARY OF BACKGROUND DATA: The anterior spine approach is a common surgery with few complications. One of the rare but significant risks is vertebral artery injury. Consequences of vertebral artery injuries are often delayed. Therefore, it is essential to prevent this complication and to know how when exploring after a suspected vertebral artery injury. METHODS: Report of a case and review of the literature. A 61-year-old woman presented with a cervical schwannoma involving the C5-C6 foramen. She had undergone surgery 22 years before by the posterior approach. We performed an anterior cervical approach. After 12 days, a vertebral artery pseudo-aneurysm occurred. Our review of the literature is focalized on vertebral artery injuries during cervical surgery by the anterior approach. RESULTS: The patient was treated by coil embolization with a good outcome. To our knowledge, only 6 cases of vertebral artery pseudo-aneurysm after surgery have been reported in the literature. CONCLUSION: According to the literature, vertebral artery pseudo-aneurysms resulting in anterior cervical approach are rare but their consequences could be severe. Prevention begins by detailed surgical planning. Peroperative imaging is helpful. Any suspected vertebral artery injury should postpone a contralateral approach before angiographic imaging.

Leukemic dissemination within a glioblastoma in a patient with chronic lymphoid leukemia.

Metastasis from an extracranial tumor to a primary central nervous system tumor is a rare event, and most reported cases concern metastases to meningiomas. The authors describe the first case of leukemic cell dissemination within a glioblastoma. The patient likely presented a genetic predisposition to multiple neoplasms, and the unusual localization of leukemic cells might be partly related to the characteristic microvascular proliferation in glioblastoma.

[Spectral analysis of the ECG R-R interval permits early detection of vagal responses to neurosurgical stimuli]. / L'analyse spectrale de l'intervalle R-R de l'ECG permet la détection précoce des réponses vagales aux stimuli neurochirurgicaux.

OBJECTIVE: To assess the efficacy of ECG spectral analysis, compared with heart rate (HR) monitoring in the detection of vagal response to surgical stimuli. METHODS: Twenty Asa II-III patients (age: 65 +/- 13 years) scheduled for surgery of cerebellopontine angle or implantation of sacral root stimulator were examined. Target controlled infusion of propofol (2-4 microg x ml(-1)) and remifentanil (4 ng x ml(-1)) was guided by the bispectral index (Bis). Arterial pressure via a radial catheter, pulse oximetry and end tidal CO2 were continuously monitored. Spectral analysis was achieved by connecting a computer to the cardiorespiratory monitor. Online power spectrum densities were calculated from the ECG R-R interval by software based on the fast Fourier transform (LabView, National Instruments, USA). Low frequency (LF: 0.04-0.15Hz) and high frequency (HF: 0.15-0.4Hz) were associated with sympathetic and parasympathetic activities respectively. We defined vagal reaction as a decrease in FC or an increase in HF >10% of the prestimuli value. HF and FC were compared according to the detection delay (by a Student t test with p < 0.05 considered significant) and a concordance test with a kappa coefficient (kappa): -1 = total discordance to 1 = total concordance. RESULTS: Twelve vagal reactions (observed in 8 patients) were detected within 5.5 +/- 1.3 s (HF) and 12.4 +/- 1.6 (FC); p < 0.001. Concordance between the 2 parameters was 95% (kappa =0.9). CONCLUSION: The ECG spectral analysis is a non-invasive technique, which permits the detection of intra-operative vagal reactions earlier than conventional monitoring of HR.

[Surgical treatment of chronic subdural hematoma in the adult. Review of the literature]. / Les traitements chirurgicaux des hématomes sous-duraux chroniques de l'adulte. Revue de la littérature.

There are various methods to treat chronic subdural hematomas in adults. "Open craniotomy" (craniotomy-membranectomy, burr-hole craniotomy) and "closed craniotomy" (twist-drill craniotomy, subdural tapping) are the most frequent technics, but endoscopy and shunts are also possible. No difference in results can be identified from a review of the literature. Different factors of recurrence are analysed.

[Functional neuronavigation. Fusion of functional MRI data in a neuronavigation system]. / Neuronavigation fonctionnelle. Fusion des données de l'IRM fonctionnelle dans un système de neuronavigation.

Neuronavigation systems integrating functional magnetic resonance imaging data have been reported recently, but generally without many details about methodology. We propose an easy method to perform functional neuronavigation by integrating functional MRI data analyzed with the Statistical Parametric Mapping 99 reference software, in the Stealth Station which is the most common neuronavigation system. Users of this new and promising technique, which requires further validation, must be aware of its limitations. Functional MRI data seem to be the major source of imprecision. As a result we do not yet recommend the use of functional neuronavigation without the control of direct cortical stimulations.

[Anterior sacral root stimulation with dorsal rhizotomy (Brindley technique)]. / Neurostimulation des racines sacrées antérieures avec rhizotomies postérieurs (technique de Brindley ).

Patients with spinal cord lesions are exposed to vesico-sphincter dysfunctions which can aggravate the vital or functional prognosis. The pathophysiological characteristics of these neurogenic bladders explains the usefulness of surgical treatment. The objective of the Brindley technique is to improve both voiding and effective continence. Any patient with a stable supra-sacral spinal cord lesion (paraplegia, tetraplegia) with a reflex bladder (incontinence, vesico-sphincter dyssynergia resistant to medical treatment with the risk of upper urinary tract involvement) can benefit from the Brindley technique. The electrodes are placed on the anterior sacral roots in order to obtain the desired micturation. Posterior sacral rhizotomies are indispensable to the technique as they suppress detrusor and sphincter hyperreflexia and improve continence thereby protecting the upper urinary tract. About 90% of the patients considered have an improved quality of life after implantation of the Brindley stimulator. The bladder capacity was constantly improved and the majority of the patients become continent. Micturation was excellent with low residual volume and low rate of urinary tract infections. Complications are analyzed in this review of the literature. The Brindley technique is an excellent alternative to medical treatment in these highly distressed patients. It restores satisfactory continence and improves psychological as well as economical constraints related to auto/hetero catheterisations performed several times a day.

[Hepatic artery aneurysm rupture after lumbar stenosis surgery. Medico-legal thinking]. / Rupture d'un anévrisme de l'artère hépatique après chirurgie de canal lombaire étroit. Réflexions médico-légales.

INTRODUCTION: Distinguishing between therapeutic contingency and surgical complication is sometimes not easy, especially when rare events occur. We report the case of a patient who presented with an intraperitoneal haemorrhage following laminectomy and discuss the implications of surgery in this complication. CASE REPORT: A 77-year-old woman, suffering from radiculopathy due to lumbar stenosis underwent a laminectomy in the prone position. On admission she presented with high blood pressure and obesity as significant comorbidities. A few hours after surgery, she collapsed and underwent a thoraco-abdominal CT-scan. The examination revealed a ruptured hepatic artery aneurysm. It is the first case published in the medical literature after lumbar surgery. The aim of this article was to discuss the responsibility of the surgeon and surgery, particularly the surgical positioning of the ruptured aneurysm. CONCLUSION: After reviewing the literature we did not find any evidence to attribute the rupture of this hepatic artery aneurysm to lumbar surgery. This adverse event could be attributed to therapeutic contingency. In cases of patient complaint, this situation depends on national solidarity.