Percutaneous vertebroplasty of the C2 body and dens using the anterior oblique ascending transdiscal approach.

This first description of percutaneous vertebroplasty (PVP) of the second cervical vertebra (C2) using an ascending oblique transdiscal approach is a case report of a 63-year-old woman who complained of neck pain that was resistant to painkillers and the result of an osteolytic metastatic lesion of C2. PVP was performed using an ascending oblique transdiscal approach, a percutaneous technique that had never been described before. It has since been used in more than 15 patients, resulting in pain relief and stabilization of C2 with good distribution of cement across the vertebral body and dens. Also, there were no complications and no leakage of cement along the path of the needle.

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.

[Vertebroplasty: 10 years clinical and radiological follow-up]. / Vertébroplastie: évaluation clinique et radiologique à plus de dix ans.

OBJECTIVES: Ten years follow-up of the first patients treated with percutaneous vertebroplasty. PATIENT AND METHODS: Eighteen patients were retrospectively reviewed having undergone vertebroplasty in our centre between 1989 and 1998. Eight were treated for angioma, eight for osteoporotic compression and two followed for myeloma. They all underwent clinical and radiological evaluation in 2007 (standard X-rays, CT scan and MRI). These examinations were compared to prior baseline pre- and post-therapeutic images. RESULTS: Radiological characteristic of cement remained unchanged in the long term and there was no modification of anatomical structures in contact with it. Even if the distribution of cement was asymmetrical there was no fracture of the treated vertebras at distance. Degenerative changes of discs facing the vertebroplasty were not more pronounced than for distant discs. We found no significant signal or density anomaly of disc in contact direct with cement. 38.8 % of the patients presented new fractures (n=30). Seventy percent of the fractures were multiple and contiguous. In the long term, all patients reported improvement of pain after the procedure. CONCLUSION: In our series, we found a good stability of treatment over time. This study shows the long-term safety of percutaneous acrylic vertebroplasty, in particular harmlessness of cement for bone and discs in contact.

[Bithalamic infarct: is there an evocative aspect? Radioclinical study]. / Accident vasculaire ischémique bithalamique: existe-t-il un tableau évocateur ? Etude radioclinique.

INTRODUCTION: Bithalamic paramedian infarcts are uncommon. This stroke results in a complex clinical syndrome. CASE REPORT: We report four cases of bithalamic paramedian infarcts with a presumed mechanism of occlusion of a single thalamic paramedian artery. DISCUSSION: This normal anatomic variant corresponds to an asymmetrical common trunk for the two thalamosubthalamic paramedian arteries arising from a P1 segment (type IIb in the G. Percheron classification dating from 1977). A literature analysis (from 1985 to 2006) allowed us to identify the most widely reported clinical signs. Four main clinical findings are described: vertical gaze palsy (65%), memory impairment (58%), confusion (53%) and coma (42%). We also found these symptoms in our patients but rarely associated; however, all four patients had exhibited episodes of drowsiness. In this article, we discuss the anatomy-function correlation responsible for such clinical variability. CONCLUSION: Clinicians should be aware of this diagnosis to better understand the imaging results which provide confirmation. Although the literature describes frequently severe consciousness disorders such as coma, this diagnosis must also be considered in patients presenting a simple fluctuation of consciousness, e.g. hypersomnia.

MRI of the spinal cord in neuromyelitis optica and recurrent longitudinal extensive myelitis.

BACKGROUND AND PURPOSE: Neuromyelitis optica (NMO) is a severe inflammatory and necrotizing disease that clinically affects the optic nerves and spinal cord in a relapsing course. We assessed the baseline and follow-up MRI characteristics of cord attacks in NMO and recurrent longitudinal extensive myelitis (RLEM). METHODS: We retrospectively reviewed MRI data of 20 Afro-Caribbean patients diagnosed with either NMO or RLEM. MRI data from 51 cord or mixed attacks were evaluated, and 65 follow-up MRI studies were available for 30 baseline acute examinations. RESULTS: The cervical cord was involved in 63% of cases. Four attacks were limited to the brainstem. MRI of the spinal cord revealed longitudinal extensive signal abnormalities extending over three vertebral segments, associated with cord swelling in 67% of the 51 relapses. Gadolinium enhancement was observed, preferentially surrounding edema, in 69% of attacks. In the axial plane, signal abnormalities typically involved central areas of the cord. Cavitation was observed in 16% of attacks. Cord attacks recurred in the same or contiguous areas in 67% of cases. Follow-up MRI revealed a gradual decrease in cord swelling and T2 signal hyperintensity, with fragmentation of signal abnormalities in some cases. Cord atrophy was evident in 57% of the follow-up MRI. CONCLUSION: Given the poor prognosis of NMO and RLEM, radiologists need to be aware of the MRI pattern to prevent further attacks with the use of aggressive treatment.

[Acute CSF changes in the mesencephalon aqueduct after subarachnoid hemorrhage as measured by PC-MRI]. / Caractérisation des perturbations du flux de LCS dans l'aqueduc du mésencéphale par IRM-CP à la phase aiguë de l'hémorragie méningée.

PURPOSE: Determining acute intracranial hydrodynamic changes after subarachnoid hemorrhage through an analysis of the CSF stroke volume (SV) as measured by phase-contrast MRI (PC-MRI) in the mesencephalon aqueduct. METHOD: A prospective study was performed in 33 patients with subarachnoid hemorrhage. A PC-MRI imaging study was performed n the acute phase (< 48 hours). CSF flow was measured in the aqueduct. The appearance of acute hydrocephalus (HCA) was then compared with data on CSF flow, and the location of the intraventricular and perimesencephalic bleeding. RESULTS: CSF analysis was performed on 27 patients, 11 of whom presented with an acute HCA. All 11 patients had an abnormal SV in the aqueduct: patients with a communicating HCA had an increased SV (n=8); and patients with a noncommunicating HCA had a nil SV (n=3). Patients with a normal SV in the aqueduct did not develop an acute HCA. Intraventricular bleeding significantly led to HCA (P=0.02), which was of the communicating type in 70% of cases. CONCLUSION: Subarachnoid hemorrhage leads to intracranial CSF hydrodynamic modifications in the aqueduct in the majority of patients. CSF flow can help us to understand the mechanism of the appearance of acute HCA. Indeed, hydrocephalus occurred - of the communicating type in most cases - even in the presence of intraventricular bleeding.

[Arterial spin labeling: state of the art]. / Etat de l'art sur le Marquage de Spin Artériel ou ASL.

UNLABELLED: Arterial spin labeling (ASL) perfusion MR imaging is a technique by which water from circulating arterial blood is magnetically labeled and acts as a diffusible tracer allowing non-invasive measurement of cerebral blood flow. In this paper, the technique and current applications in neuroimaging will be reviewed. CURRENT STATUS: First, the technical principles of ASL will be reviewed and both available techniques (continuous and pulsed ASL) explained. A review of the literature will demonstrate advances with the techniques of ASL and its clinical impact. Clinical research involves normal volunteers and patients with ischemic and tumoral pathologies. CONCLUSION: Recent technical advances have improved the sensitivity of ASL perfusion MR imaging. The routine clinical use of ASL at 3.0 Tesla should increase over the next few years.

[Sinonasal cavities: CT imaging features of anatomical variants and surgical risk]. / Cavités sinusiennes de la face: aspect scanographique des variantes anatomiques et leur risque chirurgical.

Anatomical variants of the sinonasal cavities are common. About 15 major variants are described (nasal septal deviation is present in up to 62% of the population). Because the may lead to complications at the time of endovascular procedures or endoscopic sinonasal surgery (vascular, nervous, or osseous injury), there detection has medicolegal implications. Knowledge of anatomical variants by radiologists and ENT surgeons is thus required. We will describe these variants, their imaging features, frequency, implications and associated risk of potential complication.

[MRI findings in star-fruit intoxication]. / IRM cérébrale dans l'intoxication à la carambole.

Star-fruit ingestion has been previously reported to cause severe neurotoxicity in uremic patients with symptoms ranging from hiccups, vomiting and consciousness disturbances to refractory status epilepticus, coma and death. MRI examinations of five uremic patients with severe neurological disturbances following star-fruit intoxication were reviewed. At the time of MRI, all patients presented with a confusional state, preceded by seizures in three cases. MRI showed focal (four patients) and diffuse (one patient) cortical hyperintensity on diffusion-weighted sequences, with a corresponding low apparent diffusion coefficient. An additional area of increased diffusion intensity was observed in the pulvinar (two patients) and hippocampus (two patients). MRI and diffusion-weighted imaging may be useful for the diagnosis of star-fruit neuro-intoxication which is associated with a poor prognosis and requires acute and appropriate treatment.

[Giant cystic widening of Virchow-Robin spaces, case report]. / Dilatations géantes des espaces de Virchow-Robin.

INTRODUCTION: Virchow-Robin spaces are very well-known anatomical and radiological entities. However, the observation of giant cystic widening of Virchow-Robin spaces is anecdotic. We report herein the case of a patient presenting with giant cystic widening of Virchow-Robin spaces located in both cerebral hemispheres. OBSERVATION: A 26-year-old female presented with numbness of left arm and then, of both arms. CT scan showed many hypodensities located in the two hemispheres. Neurologic examination was normal. MR imaging allowed the diagnosis of giant cystic widening Virchow-Robin spaces in T2, T2*, T1 gadolinium and Flair weighted images. Neuropsychological investigations were normal. CONCLUSION: Giant cystic widening of Virchow-Robin spaces are extremely rare entities. MR imaging helps the diagnosis. Only extreme dilatation of Virchow-Robin perivascular spaces close to ventricular system must be watched and treated in case of an obstructive hydrocephalus risk. When located in cerebral hemispheres, these dilatations are mostly asymptomatic and must not be confused with a cystic tumoral disease.

[Terminovertebral aneurysm arising from basilar artery fenestration]. / Anevrisme termino-vertebral sur fenestration de l'artere basilaire.

A case of ruptured middle saccular aneurysm arising from basilar artery fenestration is reported. Defects of the medial wall at the junctures of the fenestrated segments explain the association between vertebrobasilar aneurysms and basilar artery fenestration. A 47 year-old woman had a perimesencephalic subarachnoid hemorrhage. Immediate angiography revealed a ventral vertebrobasilar aneurysm and an endovascular coil occlusion was performed. Embryological development, pathogenesis and therapeutic difficulties are discussed.

[A rare case of nasal and buccal obstruction in a child: the antrochoanal polyp of Killian]. / Un cas rare d'obstruction nasale et buccale chez l'enfant: le polype antrochoanal de Killian.

Nasal obstruction is a frequent symptom of consultation in paediatric otorhinolaryngology. Usually, adenoid hypertrophy is the cause. Sometimes the examination reveals the presence of polyps in the nose. The antrochoanal polyp of Killian is particularly frequent in childhood. The obstruction is usually unilateral, but the posterior extension of a bulky polyp to the oropharynx can cause a major discomfort, sometimes a respiratory distress. We report the observation of a 10-year-old patient presenting a bulky polyp of Killian, visible in the oropharynx and then discuss the features of this polyp in the literature.

Temperature elevation caused by bone cement polymerization during vertebroplasty.

Percutaneous vertebroplasty (PVP), whereby polymethylmethacrylate cement is injected into the vertebral body (VB), has been used to successfully treat various spinal lesions. The mechanism responsible for the palliative effect of PVP is unknown, but it may be the result of neural damage caused by heat liberated during polymerization of the polymethylmethacrylate. The purpose of the current study was to measure in vitro temperature histories at three key locations (anterior cortex, center, spinal canal) in VBs injected with one of two different bone cements (Simplex P and Orthocomp) to determine the role temperature plays in PVP. Twelve VBs (T11-L2) from three elderly female spines were instrumented with thermocouples and injected with 10 cc of one of the two cements. Temperatures were measured with the VBs in a bath (37 degrees C) for 15 min after injection. A Student's paired t-test was used to determine differences in peak temperature and time above 50 degrees C between the two cement groups. Peak temperatures and temperatures above 50 degrees C were significantly higher and longer, respectively, at the center of VBs injected with Simplex P (61.8 +/- 12.7 degrees C; 3.6 +/- 2.1 min) than those injected with Orthocomp (51.2 +/- 6.2 degrees C; 1.3 +/- 1.4 min). There was no significant difference in peak temperature between cements at the spinal canal location; temperature there did not rise above 41 degrees C. Although thermal damage to intraosseous neural tissue caused by cement polymerization cannot be ruled out as a potential mechanism for pain relief experienced by patients subsequent to PVP, it seems unlikely based on the worst-case conditions tested in the current study.

The effect of monomer-to-powder ratio on the material properties of cranioplastic.

Percutaneous vertebroplasty consists of injecting polymethylmethacrylate cement into the cancellous bone of vertebral bodies for the treatment of various lesions of the spine, including osteoporotic compression fractures. Clinicians practicing vertebroplasty commonly alter the mixture of monomer-to-powder recommended by the manufacturer in an effort to decrease viscosity and increase the working time. The purpose of the current study was to measure the effect that varying the monomer-to-powder ratio has on the compressive material properties of a cement (Cranioplastic) commonly used in vertebroplasty. Cylindrical specimens were prepared varying a monomer-to-polymer ratio of 0.40 to 1.07 ml/g and tested per the American Society for Testing and Materials standard F451. Specimens prepared at 0.53 mL/g, which is near the manufacturer's recommended monomer-to-polymer mixture of 0.57 mL/g, exhibited the greatest mean values for ultimate compressive stress, yield stress, and elastic modulus. Specimens prepared at higher or lower ratios exhibited diminished strength, in some cases by as much as 24%. Although altering the monomer-to-powder ratio affects the cement's material properties, it is as yet unknown if the decrease is clinically significant.

An ex vivo biomechanical evaluation of a hydroxyapatite cement for use with kyphoplasty.

BACKGROUND AND PURPOSE: Previous ex vivo biomechanical studies have shown that kyphoplasty with polymethylmethacrylate cement increases vertebral body (VB) strength and restores VB stiffness and height after compression fracture. The purpose of the current study was to determine if a hydroxyapatite cement used as a void filler during kyphoplasty provides mechanical stabilization similar to that of a polymethylmethacrylate cement. METHODS: Simulated compression fractures were experimentally created in 33 osteoporotic VBs harvested from female cadaver spines. VBs were assigned to one of three groups: 1) kyphoplasty with a custom mixture of Simplex P; 2) kyphoplasty with BoneSource; and 3) no treatment. The kyphoplasty treatment consisted of inserting a balloon-like device into the VB via both pedicles, inflating the tamp, and filling the created void with Simplex P bone cement or BoneSource. VBs in the no-treatment group received no interventions. Pre- and posttreatment heights were measured, and the repaired VBs were recompressed to determine posttreatment strength and stiffness values. RESULTS: Kyphoplasty with altered Simplex P restored strength, whereas kyphoplasty with BoneSource and the no-treatment protocol both resulted in significantly weaker VBs relative to initial strength. All treatments resulted in significantly less stiff VBs relative to their initial condition. All VBs lost significant height after initial compression, but a significant amount of lost height was restored by kyphoplasty with either cement. CONCLUSION: Kyphoplasty with either cement significantly restored VB height. Kyphoplasty with altered Simplex P resulted in stronger repairs than did no treatment or kyphoplasty with BoneSource.

Preoperative percutaneous injection of methyl methacrylate and N-butyl cyanoacrylate in vertebral hemangiomas.

PURPOSE: To investigate the usefulness of preoperative percutaneous injections in vertebral hemangiomas. METHODS: Four patients presented with complicated vertebral hemangioma (spinal cord compression in three cases, intermittent spinal claudiction in one case). A three-part treatment was performed: initially, arterial embolization in three cases; 1 day later, percutaneous injections of methyl methacrylate into the vertebral body to strengthen it and of N-butyl cyanoacrylate into the posterior arch to optimize hemostasis during surgery; finally, the day after percutaneous injections, decompressive laminectomy and epidural hemangioma excision (when present). RESULTS: Laminectomy was performed with minimal blood loss. The epidural component present in three cases was excised without any difficulty. The follow-up (average, 20 months) showed no evidence of vertebral collapse. CONCLUSION: Percutaneous injections of methyl methacrylate and N-butyl cyanoacrylate might be useful before surgery for vertebral hemangiomas.

Percutaneous vertebroplasty with polymethylmethacrylate. Technique, indications, and results.

Percutaneous vertebroplasty with acrylic cement consists of injecting polymethylmethacrylate into vertebral bodies destabilized by osseous lesions. The aim is to obtain an analgesic effect by reinforcing lesions of the spine. The major indications are vertebral angiomas, osteoporotic vertebral crush syndromes, and malignant spinal tumors. The clinically significant complications occur predominantly in patients with spinal metastatics, but in the great majority of cases they resolve with medical treatment.

Endovascular treatment of a grade IV transverse sinus dural arteriovenous fistula by sinus recanalization, angioplasty, and stent placement: technical case report.

OBJECTIVE AND IMPORTANCE: The frequent association of dural arteriovenous fistulae (DAVFs) and dural sinus thrombosis may render the treatment of these complex lesions difficult. We report a case of DAVF eradicated by recanalization of the chronically thrombosed transverse sinus (TS) and sigmoid sinus followed by balloon angioplasty and stent deployment at the site of the fistula. CLINICAL PRESENTATION: A 52-year-old man presented with a Type IV DAVF of the left TS with widespread white matter changes secondary to venous hypertension. Arterial feeders arose from the left internal carotid, external carotid, and vertebral arteries. The distal segment of the left TS, the left sigmoid sinus, and the proximal segment of the right TS were occluded. Reverse flow was observed in the deep venous system and in the superior sagittal sinus. INTERVENTION: Endovascular access was gained through the left internal jugular vein. Mechanical recanalization of the thrombosed left TS and sigmoid sinus was followed by balloon angioplasty and placement of six overlapping stents extending from the TS to the proximal internal jugular vein. Angiograms performed after surgery showed resaturation of antegrade venous drainage as well as complete eradication of the fistulous connections. The patient was discharged with an improving clinical CONCLUSION: Recanalization of a chronically occluded dural venous sinus through a jugular approach is feasible. In addition to eradicating cerebral venous hypertension by reestablishing antegrade venous drainage, balloon angioplasty and stent deployment at the DAVF site produced complete closure of the fistula. This may prove to be a new therapeutic strategy for management of DAVF.