Perfusion MRI as a neurosurgical tool for improved targeting in stereotactic tumor biopsies.

OBJECTIVE: Stereotactic biopsies are subject to sampling errors (essentially due to target selection). The presence of contrast enhancement is not a reliable marker of malignancy. The goal of the present study was to determine whether perfusion-weighted imaging can improve target selection in stereotactic biopsies. METHODS: We studied 21 consecutive stereotactic biopsies between June 2009 and March 2010. Perfusion-weighted magnetic resonance imaging (MRI) was integrated into our neuronavigator. Perfusion-weighted imaging was used as an adjunct to conventional MRI data for target determination. Conventional MRI alone was used to determine the trajectory. RESULTS: We found a linear correlation between regional cerebral blood volume (rCBV) and vessel density (number of vessels per mm(2); R = 0.64; p < 0.001). Perfusion-weighted imaging facilitated target determination in 11 cases (52.4%), all of which were histopathologically diagnosed as glial tumors. For glial tumors, which presented with contrast enhancement, perfusion-weighted imaging identified a more precisely delimited target in 9 cases, a different target in 1 case, and exactly the same target in 1 other case. In all cases, perfusion-selected sampling provided information on cellular features and tumor grading. rCBV was significantly associated with grading (p < 0.01), endothelial proliferation (p < 0.01), and vessel density (p < 0.01). For lesions with rCBV values ≤1, perfusion-weighted MRI did not help to determine the target but was useful for surgical management. CONCLUSIONS: For stereotactic biopsies, targeting based on perfusion-weighted imaging is a feasible method for reducing the sampling error and improving target selection in the histopathological diagnosis of tumors with high rCBVs.

Correlation between tap test and CSF aqueductal stroke volume in idiopathic normal pressure hydrocephalus.

INTRODUCTION: The diagnosis and management of idiopathic normal pressure hydrocephalus (INPH) remains unclear despite the development of guidelines. In addition, the role of cerebrospinal fluid (CSF) aqueductal stroke volume (ASV) remains unspecified. OBJECTIVES: The aim of this study was to compare the results of the tap test (TT) and ASV in patients with possible INPH. MATERIALS AND METHODS: Among 21 patients investigated with both TT and phase-contrast (PC) MRI, we identified two groups, with either (1) a positive TT (PTT) or (2) a negative one (NTT), and we compared their ASV as measured by PC-MRI. ASV cutoff value was set at 70 µL/cardiac cycle (mean value +2 standard deviations in age-matched healthy subjects). RESULTS: In the PTT group (n = 9), the mean ASV was 175 ± 71 µL. Among these patients, four were shunted, and improved after surgery. In the NTT group, two patients were finally diagnosed with aqueductal stenosis and excluded. Among the remaining patients (n = 10), the mean ASV was 96 ± 93 µL (p < 0.05). However, three of these patients presented with hyperdynamic ASV, and an associated neurodegenerative disorder was diagnosed. Two patients had ventriculoperitoneal shunting despite their NTT, and improved. DISCUSSION/CONCLUSIONS: In our patient population, the noninvasive measurement of hyperdynamic ASV correlated with PTT, suggesting PC-MRI could be utilized to select those patients who would benefit from shunting. ASV may therefore be an interesting supplemental diagnosis tool.

Dual, minimally invasive fixation in acute, double, thoracic spine fracture.

BACKGROUND: We report on a dual percutaneous fixation in 2 patients with a double thoracic spine fracture. The advantages and limitations of this new approach for treating traumatic spinal fractures are reviewed. CLINICAL PRESENTATION: A 67-year-old male was admitted following a fall from a height of 3 m. A neurological examination revealed sub-T11 motor and sensory paraparesis. There were a T6 vertical body and bi-articular fracture and a T11 vertebral burst fracture with > 75% posterior wall damage. A 40-year-old male was admitted after a suicide attempt. A neurological examination revealed sub-T11 paraplegia. There were a T7 vertebral body fracture with intact posterior wall and a T11 burst fracture with > 75% posterior wall damage. SURGICAL TECHNIQUE: The same technique was used in both cases. 2 minimally invasive percutaneous fixations of the 2 fractures were performed. In a third step, we performed a T10-T12 open laminectomy. This technique helped to limit blood loss and avoid an over-long fixation. Pedicle screw targeting was optimal. 16 months later, the neurological status was normal in patient 1 and there was neurological improvement in patient 2. No secondary segmental kyphotic deformities appeared.Percutaneous fixation enables the treatment of an acute thoracic spine fracture. With appropriate presurgical planning, this technique can be applied to all thoracic vertebrae. Spinal cord injuries justify the use of laminectomy together with percutaneous fixation, in order to limit erector muscle injury and blood loss.

Dynamic contrast-enhanced T2*-weighted MR imaging: a peritumoral brain oedema study.

BACKGROUND AND PURPOSE: Glioma and meningioma are the two most common types of primary brain tumor. The aim of the present study was to analyze, using dynamic susceptibility contrast MR perfusion imaging, the effect of angiogenesis on peritumoral tissue. METHODS: In this prospective study, conducted from December 2003 to March 2005, out of 18 patients recruited, 12 were included (six with meningioma, six with glioblastoma). Using rates of maximum signal drop (MSD), we drew regions of interest (ROI) starting near the lesion, and gradually moving outwards to areas of distant edema in axial and sagittal planes at 10, 20 and 30 mm from the tumor. We also drew ROI on the contralateral brain white matter to obtain a normal baseline for comparison (relative MSD; rMSD). RESULTS: In regions of peritumoral T2 hypersignals, we observed a decrease in rMSD with distance from glioblastoma due to reduced angiogenesis, and an increase in rMSD with distance from meningioma, probably due to a reduced mass effect. CONCLUSION: In our study, dynamic susceptibility contrast MR perfusion imaging, using MSD as a parameter, revealed differences between meningioma and glioblastoma peritumoral tissue due to changes in angiogenesis.

[Management of intracranial dural arteriovenous fistulas with cortical venous drainage]. / Prise en charge des fistules artérioveineuses durales intracrâniennes à drainage veineux cortical.

BACKGROUND AND PURPOSE: Intracranial dural arteriovenous fistulas (DAVF) with cortical venous drainage are vascular malformations with high hemorrhagic risk. Their treatment may be complex and requires a multidisciplinary approach. METHODS: We retrospectively report 38 observations of dural arteriovenous fistulas with cortical venous drainage from 1990 to 2001. There were 28 men and 10 women with a mean age of 57 years. Hemorrhage revealed the malformation in 24 cases (63%). The other patients had headache, neurological deficit, seizure or pulsating mass of the scalp. One patient was asymptomatic. All the patients had DAVF with cortical venous drainage and decision of treatment was in each case multidisciplinary. RESULTS: Of the 38 patients, seven had no treatment for the following reasons: spontaneous occlusion of the malformation after hemorrhage, refusal of treatment, or poor neurological status at the admission. Thirty-one patients were treated and complete exclusion of the fistula was obtained in 30 cases. Endovascular occlusion of the fistula was performed in 14 patients, surgical clipping of the origin of the draining vein in 12 and combined treatment (surgical clipping after embolization of feeding arteries) in four. One patient had an untreated fistula despite several procedures. CONCLUSION: Complete exclusion of these malformations is mandatory because of the potential risk of hemorrhagic complications. The best treatment is the occlusion of the origin of the draining vein (endovascular or surgical) and requires multidisciplinary discussion.

Tension pneumocephalus and rhinorrhea revealing spontaneous cerebrospinal fluid fistula of the anterior cranial base.

Spontaneous cerebrospinal fluid fistulas (CSFFs) of the anterior skull base are extremely rare. We report a case of spontaneous CSFF of the ethmoid cribriform plate presenting with rhinorrhea and tension pneumocephalus. We discuss the physiopathology, the radiological management, and the treatment of spontaneous CSF fistulas related to the anterior skull base. A 58-year-old woman was admitted to our institution for headaches with clear rhinorrhea persisting over several days. Antecedents were unremarkable. An episode of epistaxis three days before was reported. Clinical examination showed clear rhinorrhea, headaches, and anosmia. The CT scan showed voluminous epidural and subdural pneumocephalus with mass effect on both frontal and temporal lobes. A high-resolution CT scan with bone reconstruction showed a 2-mm bony defect of the cribriform plate. Surgery consisted of epidural frontal anterior skull base repair. Postsurgery follow-up was uneventful. At one year, the patient was asymptomatic apart from the persistence of anosmia. Spontaneous CSF fistulas are uncommon and can be associated with tension pneumocephalus. The physiopathology remains unclear. Their treatment by complete exclusion of the fistula is necessary because of the lethal risk of pneumococcus meningitis.

[Follicular dural lymphoma. Case report]. / Lymphome folliculaire méningé. A propos d'un cas.

A case of a meningeal B-cell lymphoma is described. A 48-year-old man presented with an episode of grand mal seizure following a brain injury. An initial diagnosis of extradural hematoma was made based on the results of the cerebral computerized tomography scan. Magnetic resonance images demonstrated an enhanced mass with a dural tail attached to the meningeal layer of the temporal bone, suggesting a meningioma "en plaque". The mass was surgically excised. Tumoral removal was subcomplete (Simpson 2). Operative inspection also suggested a meningioma, but histological analysis and electron microscopy revealed a grade IV follicular B-cell lymphoma. Biological studies were normal. An extensive workup found an external iliac adenopathy with several osseous locations on PET. The patient underwent chemotherapy and radiotherapy. Three years after the first symptoms appeared, the patient is alive and free of symptoms. The clinicopathological features and treatments were discussed.

[Giant prebulbomedullary arachnoid cyst. Case report and review of the literature]. / Kyste arachnoïdien géant prébulbomédullaire. Cas clinique et revue de la littérature.

Usual locations of arachnoid cyst are the middle cranial fossa in 50-60%, cerebellopontine angle (10%) and suprasellar area (10%). Most of these malformations are asymptomatic. Premedullar arachnoid cysts are extremely rare. All previous cases reported were operated. We report a case of an asymptomatic giant craniocervical junction arachnoid cyst with a follow up of five years. In 2002, an adolescent consulted for persistent cervical pain. Encephalic MR showed a giant ventral craniocervical junction arachnoid cyst. Neurologic examination was normal. Conservative treatment was decided with a clinical follow up and repeated MR in case of persistent cervicalgia. Craniocervical junction arachnoid cysts are anecdotic. Medical care cannot be standardized. Pathogenesis and management are discussed.

[Endoscopic anatomy of the terminal portion of the basilar artery and its distal perforating branches]. / Anatomie endoscopique de la terminaison de l'artère basilaire et de ses perforantes distales.

The aim of this study was to describe and highlight the endoscopic anatomy of the tip of the basilar artery and its perforating branches. Knowledges of the anatomy are crucial for neurosurgeons to avoid pitfalls during endoscopic third ventriculostomy.

[Primary intramedullary lymphoma. Case report]. / Lymphome primitif intramédullaire. A propos d'un cas.

A 66-year-old female presented primary intramedullary spinal cord lymphoma. This patient was referred for lower limbs weakness, which had developed six weeks earlier and right C5 radiculalgia. Physical examination revealed a medullary syndrome with Claude-Bernard-Horner syndrome. The diagnosis was established after MRI and biopsy (dorsal myelotomy). The patient was given chemotherapy and craniospinal adjuvant radiotherapy (30 Grays). The clinical, radiological and therapeutic features are discussed.

[Paraganglioma of the cavernous sinus. Case report]. / Paragangliome du sinus caverneux. A propos d'un cas.

A case of paraganglioma arising from the cavernous area is presented. A 51-year-old woman presented with a parasellar mass causing decreased visual acuity, oculomotor nerve paresis and retro-orbital headaches without endocrinological dysfunction. Diagnosis was confirmed by histological appearance and electron microscopy. The patient was treated with surgery followed by radiation therapy consisting of 45 Gy. The clinicopathological features and the possible pathogenesis are discussed.

[Management of postoperative complications in cases of Gorham's disease with cervical spine involvement: A case report]. / Gestion des complications postopératoires dans le cas de la maladie de Gorham de localisation cervicale : cas clinique.

Gorham's disease is a rare osteolytic bone disease, caused by pathological vascular tissue, which may spread to adjacent organs. It is a disease of unknown etiology, primarily involving the axial skeleton and whose treatment is not codified. Cervical spine involvement is unusual. Stabilization of the cervical spine is a real surgical challenge. We report the case of a young adult treated in our neurosurgery department for a cervical spine localization of Gorham's disease.

[Intracranial facial nerve schwannomas. Seven cases reviewed]. / schwannomes du nerf facial intracranien. à propos de 7 observations.

BACKGROUND AND PURPOSE: Intracranial facial nerve schwannomas are rare neoplasms. Preoperative diagnosis is difficult because of non-specific clinical presentations (deafness, facial paralysis sudden or progressive) and radiological differential diagnosis (petrous bone tumor, vestibular schwannoma). Treatment depends on localization and has to be discussed for each case. METHODS: Seven cases (four men and three women) of intracranial facial nerve schwannomas were retrospectively studied. RESULTS: Before treatment, we found deafness in six cases (two sudden and four progressive), a facial palsy in five cases (three sudden and two progressive). Five patients had deafness and facial palsy. One patient had only headache. Three schwannomas were supra and intra-petrous, two in the cerebello-pontine angle, and two were plurifocal (petrous bone, internal auditive canal and cerebellopontine angle). Six patients were operated on with an oto-neurosurgical procedure. After treatment, facial palsy always worsened (requesting secondary hypoglosso-facial anastomosis in cinq cases). Only one case of transmission deafness improved after ossiculoplasty. One patient is still under clinical and radiological observation. CONCLUSION: Diagnosis is difficult and made operatively in half of patients. A large tumor requires surgery, but surveillance can be a good option for a small one, considering the risk of postoperative facial palsy.

Lhermitte-Duclos disease and Cowden's syndrome. Report of two cases.

OBJECTIVE AND IMPORTANCE: Lhermitte-Duclos disease, or dysplastic cerebellar gangliocytoma is a rare entity characterized by a hamartomatous lesion in the posterior fossa. Cowden's syndrome, or hamartoma-neoplasia syndrome is a rare underdiagnosed autosomal dominant genodermatosis with high incidence of malignant tumors. Several recent reports suggest that Lhermitte-Duclos disease may be a component of Cowden's syndrome. CLINICAL PRESENTATION: We report two cases of Lhermitte-Duclos and Cowden disease occurring in adult patients. A 40-year-old woman had symptoms of raised intracranial pressure and macrocephaly. She displayed the stigmata of fibrocystic breast disease, thyroid goitre. Clinical examination showed mucocutaneous lesions. Her mother, brother and uncle had manifestations of Cowden's disease. An asymptomatic 38-year-old male had bilateral optic nerve drusen related to a cerebellar neoplasm. He exhibited manifestations of Cowden's syndrome and his familial history confirmed this hypothesis. INTERVENTION: The first patient was operated on for Lhermitte-Duclos disease. A conservative strategy was performed for the second patient and the clinical and imaging follow-ups were uneventful over 5 years. CONCLUSION: We stress the possibility that Lhermitte-Duclos and Cowden disease might be a peculiar form of phakomatosis. A conservative strategy can be chosen without neurological signs because of slow tumor growth. However, these patients should be carefully examined and followed up because of the risk of future malignancy.

[Target-controlled infusion with propofol for neuro-anesthesia]. / Le propofol et l'AIVOC en neuro-anesthésie.

Propofol is an intravenous anaesthetic agent, which presents interesting features for its use in neuro-anaesthesia: it is a powerful hypnotic that does not increase the intracranial pressure. The delay of recovery is short even after several hours of continuous infusion. This is essential for a fast neurologic examination. Continuous infusion should be preferred to bolus in order to prevent hypotension and decrease of the cerebral perfusion pressure. Target-controlled infusion models based on effect site concentrations are now available through several softwares. This technique appears especially useful for awake craniotomy and functional neurosurgery. The level of consciousness is easily fixed between deep anaesthesia and light sedation permitting to ask the patient to move following orders. A sedation controlled by the patient himself is even possible.

[Chronic subdural hematoma in patients over 80 years of age]. / L'hématome sous-dural chronique chez les patients de plus de 80 ans.

Eighty cases of chronic subdural haematomas (SDH) in elderly patients (over 80 year-old) are reported retrospectively. The estimated incidence of the disease is 17 cases per 10(5) per year. The main presenting symptoms were confusion and impaired mentation. Surgical treatment was performed in all patients. Biological disorders deserved particular attention in the elderly SDH population. Complications occurred in 10% of patients, and recurrence of SDH was noted in 5% of patients. After their hospital discharge, 85% of patients returned to their previous neurological status. In this study, the age of patients did not appear to be a poor prognostic factor.

[Diagnostic problems in brain abscess: 45 cases]. / L'abcès cérébral reste un problème diagnostique. A propos de 45 cas.

BACKGROUND AND PURPOSE: We analysed the difficulties encountered in the differential diagnosis between brain abscess and brain tumor and their influence on treatment and outcome. METHODS: - Forty-five adults with brain abscess operated on between 1993 and 1999 were retrospectively reviewed. We studied preoperative diagnosis, clinical, radiological, bacteriological findings, surgical procedure, primary sources of infection and outcome. RESULTS: Preoperative diagnosis was right in 55.6% (25/45), wrong in 22.2% (10/45) and doubtful in 22.2% (10/45). Diffusion-weighted MR imaging was successfully used in 4 doubtful cases to make the differential diagnosis between abscess and tumor. When the preoperative diagnosis was right, the surgical procedure was a burr-hole aspiration in 73.3% (22/25) whereas when it was wrong, an excision was performed in 60% (6/10) of the cases. Aspiration was the last diagnostic investigation in 80% (8/10) of doubtful cases. Microbacterial organisms were identified in 75.5% (34/45) of the cases and primary cause of infection in 62.2% (28/45). The outcome depended on clinical status on admission, preoperative diagnosis and surgical procedure. In four cases, diffusion-weighted MRI allowed differential diagnosis between brain abscess and tumor through calculation of the Apparent Diffusion Coefficient which is low in abscess and high in cystic tumor. CONCLUSION: The diagnosis of brain abscess remains difficult in certain patients. Correct preoperative diagnosis influences the decision on the appropriate surgical procedure and helps improve outcome.

[Frontal sinus osteomas: neuro-ophthalmological complications]. / Complications neuro-ophtalmologiques des ostéomes des sinus frontaux.

Osteomas are the most frequent benign tumors of the paranasal sinuses. They often grow in the frontal sinus near the nasofrontal duct. They remain frequently asymptomatic and they tend to be an incidental finding on radiographic studies. Rarely, they extend out of the sinus limits. Two cases with neuro-ophthalmological complications are reported and discussed. A 19-year-old female presented with a progressive left visual impairment and orbital bone deformity. A CT-scan revealed a large calcified mass in both frontal sinuses, with left intraorbital and frontobasal extension. A 21-year-old man suffered from acute frontoethmoidal sinusitis. Radiological exams revealed a right frontal sinus osteoma with bilateral nasofrontal ducts obstruction. The frontal sinus cavities were filled with a large mucocele with intracranial extension. Both patients were successfully treated using frontobasal craniotomy with complete osteoma and mucocele removal and cranio facial bone reconstruction. Neuro-ophthalmological or intrasinusal complications of osteomas lead to radical treatment. CT-scan and MRI analysis for surgical purpose and strategy are emphased.

Should we fear cement leakage during kyphoplasty in percutaneous traumatic spine surgery? A single experience with 76 consecutive cases.

OBJECTIVE: Although kyphoplasty is widely used to repair osteoporotic and pathologic vertebral fractures, balloon kyphoplasty and vertebral body stenting are new treatment options in cases of traumatic spinal injury. To our knowledge, there are no literature data on the incidence of cement leakage whereas these two percutaneous techniques are commonly used to repair non-pathologic fractures. The aim of this study was to evaluate and compare the clinical characteristics and the incidence of cement leakage associated with balloon kyphoplasty and vertebral body stenting in the percutaneous treatment of traumatic spinal injury. METHODS: A series of 76 consecutive kyphoplasties (50 with vertebral body stenting and 26 balloon kyphoplasties) were retrospectively reviewed. Preoperative and postoperative computed tomography scans were analyzed in order to detect cement leakage and grade it as minor, moderate or major. RESULTS: The overall leakage rate was 50%. None of the leakages gave rise to clinical symptoms. Although balloon kyphoplasty and vertebral body stenting did not differ in terms of the leakage rate, the latter technique was associated with a lower leakage volume. The Magerl type, fracture level and use of concomitant osteosynthesis did not appear to significantly influence the leakage rate. CONCLUSION: Vertebral body stenting can reduce the amount of cement leakage due to a better cohesion of the bone fragments after kyphosis correction and maintenance.

[Brown-Sequard syndrom complicating a C6 teardrop fracture associate with an occult vertebral artery dissection: case report]. / Syndrome de Brown-Séquard compliquant une fracture teardrop de C6 associée à une dissection d'une artère vertébrale asymptomatique : à propos d'un cas.

CASE REPORT: We report the case of a 27-year-old man, presenting a C6 tear-drop fracture associated to medullar contusion with a Brown-Sequard syndrome. An asymptomatic right vertebral artery dissection in its V2 portion was also discovered by the radiologic investigations. A surgical treatment and antiplatelet therapy were performed. The patient outcome was quite satisfactory.