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.

Minimally invasive management of thoraco-lumbar fractures: combined percutaneous fixation and balloon kyphoplasty

STUDY DESIGN

Retrospective review of prospectively collected data.

BACKGROUND

There is no consensus regarding the ideal treatment of thoraco-lumbar spine fractures without neurological compromise. Many surgical techniques have been described but none has proved its definite superiority. The main drawback of these procedures is directly related to the morbidity of the approach. As minimally invasive fixation combined with balloon kyphoplasty for treatment of thoraco-lumbar fractures is gaining popularity, its efficacy has yet to be established.

PURPOSE

The purpose of this study is to report operative data, clinical and radiological outcomes of patients undergoing minimally invasive management of thoraco-lumbar fracture at our institutions.

METHODS

Forty-one patients underwent percutaneous kyphoplasty and stabilization for treatment of single-level fracture of the thoracic or lumbar spine. All patients were neurologically intact. There were 20 males and 21 females with an average age of 50 years.

RESULTS

The mean follow-up was 15 months (3-90 months). The mean operative time was 102 minutes (range 35-240 minutes) and the mean blood loss was <100mL. VAS was significantly improved from 6.7 to 0.7 at last follow-up. Vertebral kyphosis decreased by 16° to 7.8° postoperatively (P<0.001). Local kyphosis and percentage of collapse were also significantly improved from 8° to 5.6° and from 35% to 16% at last follow-up. Fifteen leaks have been identified, three of which were posterior; all remained asymptomatic. No patient worsened his or her neurological condition postoperatively.

CONCLUSION

Percutaneous stabilization plus balloon kyphoplasty seems to be a safe and effective technique to manage thoraco-lumbar fractures without neurological impairment.

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.

[Vertebroplasty: 10 years clinical and radiological follow-up]

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.

[Arterial spin labeling: state of the art]

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.

Balloon-related complications and technical failures in kyphoplasty for vertebral fractures

BACKGROUND AND PURPOSE

Our aim was to describe the immediate or early complications and technical failures occurring during balloon kyphoplasty (BKP) procedures and attributable to balloon inflation.

MATERIALS AND METHODS

We performed a retrospective review of all consecutive kyphoplasty procedures performed in our institution from May 2005 to October 2006. Fifty-one patients were treated by BKP at 75 spinal levels, and 137 vertebroplasties were performed as well.

RESULTS

Several recurrent complications or procedural failures were observed during BKP: cortical or endplate fracture by balloon expansion (4 vertebrae), partial vertebral re-collapse after deflation (4 vertebrae), balloon rupture during inflation (5 vertebrae), and transient hyperalgia after the procedure (11 patients, 27.5%).

CONCLUSIONS

Several symptomatic or asymptomatic complications and technical failures can occur during BKP. Some modifications of the usual kyphoplasty technique may decrease the frequency of these complications.

[Sinonasal cavities: CT imaging features of anatomical variants and surgical risk]

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 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.

3T MR imaging of postoperative recurrent middle ear cholesteatomas: value of periodically rotated overlapping parallel lines with enhanced reconstruction diffusion-weighted MR imaging

BACKGROUND AND PURPOSE

MR diagnostic of postoperative recurrent cholesteatomas is difficult. Our purpose was to compare multishot fast spin-echo periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) diffusion-weighted MR imaging (DWI) with array spatial sensitivity encoding technique (ASSET) single-shot echo-planar DWI and late postgadolinium T1-weighted MR imaging for the detection of postoperative recurrent middle ear cholesteatomas with a 3T imaging unit.

MATERIALS AND METHODS

Thirty-five patients with suggested postoperative recurrent middle ear cholesteatoma underwent 3T MR imaging with PROPELLER DWI, ASSET echo-planar DWI, and late postgadolinium T1-weighted MR imaging. Three radiologists (2 seniors, 1 fellow) analyzed unlabeled images for visualization of recurrence. Interobserver and intraobserver agreement was assessed by using the Cohen kappa statistic test. Sensitivity, specificity, and predictive value were assessed for the 3 observers.

RESULTS

Nineteen recurrent cholesteatomas were diagnosed. PROPELLER interobserver agreement was very good (1, 0.89, 0.89) among the 3 observers. Intraobserver agreement between PROPELLER and T1-weighted imaging was very good to moderate (0.88, 0.57, 0.58). PROPELLER DWI provided less interobserver variability than other sequences, and the best sensitivity, specificity, and predictive value.

CONCLUSIONS

On a 3T imaging unit, multishot fast spin-echo PROPELLER DWI allows an easier detection of postoperative recurrent middle ear cholesteatoma than T1-weighted imaging by reducing artifacts and by its better contrast. DWI with PROPELLER is diagnostically robust and accurate.

Dynamic measurements of total hepatic blood flow with Phase Contrast MRI

BACKGROUND/AIMS

To measure total hepatic blood flow including portal and proper hepatic artery flows as well as the temporal evolution of the vessel's section during a cardiac cycle.

METHODS

Twenty healthy subjects, with a mean age of 26 years, were explored. Magnetic resonance imaging blood flow measurements were carried out in the portal vein and the proper hepatic artery. MR studies were performed using a 1.5T imager (General Electric Medical Systems). Gradient-echo 2D Fast Cine Phase Contrast sequences were used with both cardiac and respiratory gatings. Data analysis was performed using a semi-automatic software built in our laboratory.

RESULTS

The total hepatic flow rate measured was 1.35+/-0.18L/min or 19.7+/-4.6mL/(minkg). The proper hepatic artery provided 19.1% of the total hepatic blood flow entering the liver. Those measurements were in agreement with earlier studies using direct measurements. Mean and maximum velocities were also assessed and a discrepancy between our values and the literature's Doppler data was found. Measurements of the portal vein area have shown a mean variation, defined as a "pulsatility" index of 18% over a cardiac cycle.

CONCLUSIONS

We report here proper hepatic artery blood flow rate measurements using MRI. Associated with portal flow measurements, we have shown the feasibility of total hepatic flowmetry using a non-invasive and harmless technique.

[Giant cystic widening of Virchow-Robin spaces, case report]

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.

[Acute CSF changes in the mesencephalon aqueduct after subarachnoid hemorrhage as measured by PC-MRI]

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.

[Terminovertebral aneurysm arising from basilar artery fenestration]

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.

Fistule carotido-caverneuse traumatique

The diagnosis of carotid-cavernous sinus fistula is based on clinical findings and must be confirmed and detailed by CT scan and arteriography. If the treatment, based on embolization, is not undertaken in the emergency room, visual complications or even death may result. We give an example of a direct post-traumatic carotid-cavernous sinus fistula, stressing its clinical characteristics (ophthalmoplegia) and treatment: the advantages of arteriography and of embolization methods (most often by detachable balloon or coils, through arteries or veins).

[A rare case of nasal and buccal obstruction in a child: the antrochoanal polyp of 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.

Les ruptures anévrismales intracrâniennes per-embolisation

OBJECTIVE

The purpose of this study is to determinate the frequency, causes, management and outcome of aneurysmal rupture occurring during embolization. We present our experience with this severe and feared complication.

METHODS

We retrospectively reviewed 314 acute cerebral aneurysms that were treated with endovascular coiling. These patients were identified and the management and outcomes were recorded. The literature was reviewed.

RESULTS

Six patients had an intraprocedural aneurysmal rupture. This complication occurred sporadically. Prevalence was 1.9%. Of these six, four were women and two were men. The mean age was 68 years (range: 43-74 years). Four aneurysms were located in the anterior circulation and two in the posterior circulation. Perforation occurred during microcatheterization of the aneurysm in one case and during coil deposition in five cases. In these five patients, aneurysmal rupture resulted from detachment of the first coil in three patients and detachment of the third and last coil in two patients. Hemodynamic changes were noted for one patient. The Glasgow Outcome Scale score at last follow-up examination was 1 in three patients and 3 in one patient (fair recovery). Mortality was 33% and morbidity was 16.7%.

CONCLUSION

Aneurysmal perforation during embolization is a rare event (1.8 to 4.4%). When perforation is recognized, embolization can be completed immediately with further coil deposition and reversal of anticoagulation therapy.

Intérêt de la vertébroplastie percutanée acrylique dans les compressions médullaires tumorales

We report two cases of spinal cord compression due to vertebral hemangioma in the first patient and myeloma in the other. Vertebroplasty was performed in both patients, combined with surgery for the first and radiotherapy for the second. Postprocedural pain decreased within 24 hours. Indications for percutaneous vertebroplasty are limited to aggressive vertebral hemangiomas, malignant spinal tumors including metastasis, multiple myeloma and solitary bone plasmocytoma. Vertebroplasty consolidates the vertebral body and reduces the risk of hemorrhage. It allows provides a rapid analgesic effect, radicullomedullary decompression associated with neurosurgery, spinal stabilization and can restrict progression of vascular malformations or tumors. Incidents and complications appear to be rare.

The dural crossing of the vertebral artery

The aim of this study was to present the anatomic and macroscopic aspects of the vertebral artery at the level of the dural crossing. Twenty vertebral arteries in 10 cadavers were dissected. The preparations were photographed and all the samples at the level of the dural crossing were submitted to a histologic study. Macroscopic results allow specification of the relationships between the dural crossing of the vertebral artery and the nervous elements (C1 and C2 nerves, mixed nerves), the vascular elements (postero-inferior cerebellar artery), the dural sheath and the first two dentate ligament tips. Microscopic results show the intricate relationship of the different layers of the vertebral artery with the dura at its crossing. Dural fibers reinforce the adventitial fibers not only by continuing them in their contact, much as the pages of a book, but also by being encrusted into the adventitia up to the tunica media, thus creating a very efficient mooring system. This work provides some information for an understanding of the symptoms induced by foramen magnum meningiomas and the onset of clinical signs after the surgical excision of these tumors. It also explains why dissections of the suboccipital segment of the vertebral artery stop at the level of the dural crossing, and never spread towards the intracranial segment.

[Central neurocytoma: case report]

The authors report a case of intraventricular tumor. The tumor was initially misdiagnosed as an oligodendroglioma but later proved to be a central neurocytoma. The imaging and histopathological features are reviewed. The immunopositivity allows a diagnosis of neurocytoma. Prognosis is favorable following total surgical resection, with low recurrence rate.

[Lenticulostriate aneurysms. Radioclinical study]

The authors report four cases of aneurysm of the lenticulostriate arteries, three idiopathic and one with underlying MoyaMoya disease. This unusual pathology, which often affects young patients, is revealed by a meningeal syndrome and sometimes focal neurological signs. The bleeding is highlighted by a CT scan without contrast injection, even by MRI, these examinations making it possible to evaluate its repercussion. Arteriography or MRA show the aneurysm and eliminate vascular malformation. According to literature (15 cases published) and our experience, considering the difficulty of a surgical or endovascular approach, morbidity and the frequency of spontaneous thromboses, it seems that a conservative management is justified after a negative etiologic check-up and under radio-clinical monitoring.

Material properties of various cements for use with vertebroplasty

The purpose of the current study was to measure the material properties of various cements prepared per manufacturers' recommendations and of cements modified according to compositions developed by clinicians with experience performing vertebroplasty. Cement was prepared, cast to form cylindrical specimens, and tested in compression. The optical density of specimens from the various cement preparations was measured. Batches of Simplex P and Cranioplastic cement were also prepared with increased concentrations of BaSO4 (20% and 30%; and 10%, 20% and 30%, respectively) to evaluate the effect of additional BaSO4. Compressive modulus values for polymethylmethacrylate cements ranged from 2-2.7 GPa; some differences were significant (p<0.05). Compared with polymethylmethacrylate cements, Orthocomp exhibited almost twice the compressive modulus and 2-3 times the strength values. Increasing the BaSO4 concentration in Simplex P and Cranioplastic significantly (p<0.05) affected their material properties; however, it is unknown if these changes in material properties are clinically important. Optical density increased as a function of concentration of the opacifying agent added. The current study provides clinicians with information on changes in the material properties of bone cements when the compositions are altered in a manner consistent with the practice of vertebroplasty.

The biomechanics of vertebroplasty. The effect of cement volume on mechanical behavior

STUDY DESIGN

Ex vivo biomechanical study using osteoporotic cadaveric vertebral bodies.

OBJECTIVE

To determine the association between the volume of cement injected during percutaneous vertebroplasty and the restoration of strength and stiffness in osteoporotic vertebral bodies, two investigational cements were studied: Orthocomp (Orthovita, Malvern, PA) and Simplex 20 (Simplex P with 20% by weight barium sulfate content; Stryker-Howmedica-Osteonics, Rutherford, NJ).

SUMMARY OF BACKGROUND DATA

Previous biomechanical studies have shown that injections of 8-10 mL of cement during vertebroplasty restore or increase vertebral body strength and stiffness; however, the dose-response association between cement volume and restoration of strength and stiffness is unknown.

METHODS

Compression fractures were experimentally created in 144 vertebral bodies (T6-L5) obtained from 12 osteoporotic spines harvested from female cadavers. After initial strength and stiffness were determined, the vertebral bodies were stabilized using bipedicular injections of cement totaling 2, 4, 6, or 8 mL and recompressed, after which post-treatment strength and stiffness were measured. Strength and stiffness were considered restored when post-treatment values were not significantly different from initial values.

RESULTS

Strength was restored for all regions when 2 mL of either cement was injected. To restore stiffness with Orthocomp, the thoracic and thoracolumbar regions required 4 mL, but the lumbar region required 6 mL. To restore stiffness with Simplex 20, the thoracic and lumbar regions required 4 mL, but the thoracolumbar region required 8 mL.

CONCLUSION

These data provide guidance on the cement volumes needed to restore biomechanical integrity to compressed osteoporotic vertebral bodies.

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

STUDY DESIGN

Comparative ex vivo biomechanical study.

OBJECTIVE

To determine the strength and stiffness of osteoporotic vertebral bodies subjected to compression fractures and stabilized via bipedicular injections of the following: 1) Simplex P (Stryker-Howmedica-Osteonics, Rutherford, NJ), 2) Simplex P formulated consistent with the practice of vertebroplasty (F2), or 3) BoneSource (Stryker-Howmedica-Osteonics).

SUMMARY OF BACKGROUND DATA

Little is known about the mechanical stabilization afforded by new materials proposed for use with vertebroplasty.

METHODS

Vertebral bodies (T8-T10 and L2-L4) from each of 10 fresh spines were harvested from female cadavers (81 +/- 12 years), screened for bone density (t score, -3.8 +/- 1.1; bone mineral density, 0.75 +/- 15 g/cm2), disarticulated, and compressed to determine initial strength and stiffness. The fractured vertebral bodies were stabilized via bipedicular injections of 4 mL (thoracic) or 6 mL (lumbar) and then recrushed.

RESULTS

Vertebral bodies repaired with Simplex P resulted in significantly greater strength (P < 0.05) relative to their prefracture states, those repaired with BoneSource resulted in the restoration of initial strength for both the thoracic and lumbar level, and those repaired with F2 resulted in significantly greater strength (P < 0.05) in the thoracic region and restoration of strength in the lumbar region. All cement treatments resulted in significantly less stiffness compared with initial values.

CONCLUSIONS

All three materials tested restored or increased vertebral body strength, but none restored stiffness. Both new materials show promise for use in percutaneous vertebroplasty, but they need clinical evaluation.

Percutaneous Vertebroplasty

Percutaneous vertebroplasty (PVP) with acrylic cement [polymethylmethacrylate (PMMA)]consists of injecting PMMA into vertebral bodies weakened by osseous lesions. The aim of PVP with PMMA is to obtain an antalgic effect by consolidation in destructive lesions of the spine. There are three major indications: vertebral angiomas, osteoporotic vertebral crush syndromes, and malignant vertebral tumors. Indications in vertebral angiomas only concern patients with aggressive clinical signs (severe pain or nervous compression) and/or aggressive radiological signs. Indications in osteoporotic vertebral crush syndromes only concern patients suffering from back pain related to one or two adjacent vertebral collapses resistant to medical treatment for several weeks. Indications in malignant vertebral tumors only concern patients suffering from severe back pain related to a destruction of the vertebral body, not involving the major part of the cortical bone. Complications of PVP occur essentially in patients with vertebral metastasis. In the great majority of cases, these complications heal under medical treatment. In patients with osteoporotic vertebral crush syndromes or vertebral angiomas, the complications are represented by the increase or onset of radiculalgias (in less than 1%), which disappear after local anesthetic injection.

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.

Prevalence of Paget's disease of bone and spinal hemangioma in French women older than 75 years: data from the EPIDOS study

OBJECTIVE

To evaluate the prevalence in France of Paget's disease in elderly women.

PATIENTS AND METHODS

The prevalences of Paget's disease and of thoracic and lumbar vertebral hemangioma were determined in a random nested cohort of 770 women from the EPIDOS study cohort. EPIDOS is a prospective study of the risk of proximal femoral fracture in 7,598 female, community-dwelling volunteers older than 75 years of age. The EPIDOS study patients were recruited at five centers in France (Amiens, Lyon, Paris, Montpellier, and Toulouse). For the nested study, anteroposterior and lateral radiographs of the thoracic and lumbar spine were read by two rheumatologists and classified into four groups: no Paget's disease or hemangioma, possible Paget's disease or hemangioma, definite Paget's disease, and definite hemangioma. Radiographs in the last three groups were read by a rheumatology professor and a radiology professor, both independent from the study.

RESULTS

Twenty-five patients had incomplete or poor-quality radiograph sets, leaving 745 patients for the study. A vertebral hemangioma was found in four patients (0.54%; 95% confidence interval [CI], 0.01-1.1%) and vertebral Paget's disease in four other patients (0.54%; 95% CI, 0.01-1.1 %). All the pagetic vertebrae were at the lumbar spine. Three of the four Paget's disease patients were unaware of the condition before their inclusion in the study. Based on previous estimates that thoracic and lumbar foci are present in 30 to 50% of Paget's disease patients, our data suggest that the overall prevalence of Paget's disease in French women older than 75 years may be in the 1.1-1.8% range.

CONCLUSION

The prevalence of Paget's disease in elderly French women is similar to that recently reported in Britain.

Long-term observations of vertebral osteoporotic fractures treated by percutaneous vertebroplasty

OBJECTIVE

To assess the immediate and long-term efficacy and safety of percutaneous vertebroplasty with polymethylmethacrylate (PMMA) for the treatment of refractory pain resulting from osteoporotic vertebral fractures.

METHODS

A retrospective, open study of percutaneous vertebroplasty (PV) was conducted with long-term follow-up. PV with PMMA was carried out between 1990 and 1996 in 40 patients with symptomatic osteoporotic vertebral fracture(s) that had not responded to maximum medical therapy. In 1997, each patient was asked to come back to our institution for a physical and spinal X-ray examination. Efficacy was assessed by changes over time in pain on Huskisson's visual analogue scale (VAS).

RESULTS

Thirty-four vertebrae treated by PV in 25 patients were evaluated with long-term follow-up. The mean duration of follow-up was 48 months (range 12-84 months). Pain assessed by the VAS significantly (P<0.05) decreased from a mean of 80 mm+/-16 (S.D.) before PV to 37+/-24 mm after 1 month and 34+/-28 mm at the time of maximal follow-up. There was no severe complication related to this treatment, and no progression of vertebral deformity in any of the injected vertebrae. However, there was a slight but significantly increased risk of vertebral fracture in the vicinity of a cemented vertebra (odds ratio 2.27, 95% confidence interval 1.1-4.56). The odds ratio of a vertebral fracture in the vicinity of an uncemented fractured vertebra was 1.44 (0.82-2.55).

CONCLUSION

PV appears to be a safe and useful procedure for the treatment of focal back pain secondary to osteoporotic vertebral fracture when conservative treatment has failed.

Percutaneous vertebroplasty in benign and malignant disease

Based on experience, published data, and published series, the authors recommend the use of vertebroplasty for painful destructive vertebral lesions. In the authors' opinion, the greatest difficulty lies in denying the treatment to patients with advanced metastatic disease, where other surgical or medical treatments may have greater morbidity and mortality. The few complications reported have been related to excessive PMMA injection, underlining the need for excellent imaging conditions to control the cement injection.

[Imaging of tumors of the third ventricle]

MR imaging now appears as the best tool for diagnosis and pre-therapeutic assessment of tumors arising in the third ventricle (V3), as MR images can be obtained in the axial, coronal, and sagittal planes. MRI makes certain the location of the tumor in the V3 and delineates the anatomical landmarks in order to plan the surgical approach. It also allows the evaluation of associated hydrocephalus. Colloid cysts, choroid plexus papillomas, cavernomas, subependymal giant cell astrocytomas and germ-cell tumors may exhibit specific radiological features.

[Bilateral carotid paraganglioma]

We report an unusual case of bilateral paraganglioma of the carotid. The tumor had been neglected for a long time and increased in volume during pregnancy, inducing compression and requiring surgical treatment. We focus on the therapeutic strategy: devascularization followed by percutaneous sclerosis before total surgical removal in a two-step procedure.

[MR diffusion and perfusion imaging in clinical practice]

MR functional imaging, due to the improvement in ultra-speed imaging technology such as echo-planar imaging, has become a very powerful technique since the beginning of the nineties. This imaging technique is divided into diffusion imaging, perfusion imaging and cerebral activation. Diffusion imaging probes the mobility of water molecules characterized by a diffusion coefficient called the apparent diffusion coefficient (ADC) for biological tissues. Perfusion imaging gives hemodynamic information due to the regional cerebral blood volume by the use of contrast agents such as chelates of gadolinium carrying strong magnetic susceptibility. Both imaging techniques can provide information in a wide nosological range : cerebral ischemia, in the acute phase and in case of intracranial tumors, contributing to tumoral grading, localizing the site of biopsy, and assessing response to therapy (after radiotherapy for example). Nevertheless, a wide range of domains remains incompletely studied, for example cerebral white matter diseases and neurodegenerative diseases. For clinical applications, a precise knowledge of the potentials of both techniques and their limitations is needed. Limitations result from the large number of often patient-related parameters, imaging technique (perfusion) and data analysis. Powerful software has been developed in the workstation environment. Thus this imaging technique requires up-to-date equipment and close collaboration between clinical and research teams for optimal efficiency.

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.