A mysterious risk factor for bone cement leakage into the spinal canal through the Batson vein during percutaneous kyphoplasty: a case control study.

BACKGROUND: Percutaneous kyphoplasty (PKP) can effectively treat osteoporotic vertebral compression fractures (OVCFs). Although satisfactory clinical outcomes can be achieved, bone cement leakage remains a primary complication of PKP. Previous studies have found many high risk factors for bone cement leakage into the spinal canal; however, less attention to the posterior wall morphologies of different vertebral bodies may be one reason for the leakage. Here, we investigated the effect of posterior vertebral wall morphology in OVCF patients on bone cement leakage into the spinal canal during PKP. METHODS: Ninety-eight OVCF patients with plain computed tomography (CT) scans and three-dimensional (3D) reconstruction images from T6 to L5 were enrolled. 3D-CT and multiplanar reconstructions (MPR) were used to measure the concave posterior vertebral wall depth (PVWCD) and the corresponding midsagittal diameter of the nonfractured vertebral body (VBSD), and the PVWCD/VBSD ratio was calculated. All subjects were divided into the thoracic or lumbar groups based on the location of the measured vertebrae to observe the value and differences in the PVWCD between both groups. The differences in PVWCD and PVWCD/VBSD between the thoracic and lumbar groups were compared. Three hundred fifty-seven patients (548 vertebrae) who underwent PKP within the same period were also divided into the thoracic and lumbar groups. The maximal sagittal diameter (BCSD), the area of the bone cement intrusion into the spinal canal (BCA), and the spinal canal encroachment rate (BCA/SCA × 100%) were measured to investigate the effect of the thoracic and lumbar posterior vertebral wall morphologies on bone cement leakage into the spinal canal through the Batson vein during PKP. RESULTS: The PVWCDs gradually deepened from T6 to T12 (mean, 4.6 mm); however, the values gradually became shallower from L1 to L5 (mean, 0.6 mm). The PVWCD/VBSD ratio was approximately 16% from T6 to T12 and significantly less at 3% from L1 to L5 (P < 0.05). The rate of bone cement leakage into the spinal canal through the Batson vein was 10.1% in the thoracic group and 3.7% in the lumbar group during PKP. In the thoracic group, the BCSD was 3.1 ± 0.5 mm, the BCA was 30.2 ± 3.8 mm2, and the BCA/SCA ratio was 17.2 ± 2.0%. In the lumbar group, the BCSD was 1.4 ± 0.3 mm, the BCA was 14.8 ± 2.2 mm2, and the BCA/SCA ratio was 7.4 ± 1.0%. The BCSD, BCA and BCA/SCA ratio were significantly higher in the thoracic group than in the lumbar group (P < 0.05). CONCLUSIONS: The PVWCD in the middle and lower thoracic vertebrae can help reduce bone cement leakage into the spinal canal by enabling avoiding bone cement distribution over the posterior 1/6 of the vertebral body during PKP. The effect of the difference between the thoracic and lumbar posterior vertebral wall morphology on bone cement leakage into the spinal canal through the Batson vein in OVCF patients during PKP is one reason that the rate of bone cement leakage into the thoracic spinal canal is significantly higher than that into the lumbar spinal canal.

Patient-specific cranio-spinal compliance distribution using lumped-parameter model: its relation with ICP over a wide age range.

BACKGROUND: The distribution of cranio-spinal compliance (CSC) in the brain and spinal cord is a fundamental question, as it would determine the overall role of the compartments in modulating ICP in healthy and diseased states. Invasive methods for measurement of CSC using infusion-based techniques provide overall CSC estimate, but not the individual sub-compartmental contribution. Additionally, the outcome of the infusion-based method depends on the infusion site and dynamics. This article presents a method to determine compliance distribution between the cranium and spinal canal non-invasively using data obtained from patients. We hypothesize that this CSC distribution is indicative of the ICP. METHODS: We propose a lumped-parameter model representing the hydro and hemodynamics of the cranio-spinal system. The input and output to the model are phase-contrast MRI derived volumetric transcranial blood flow measured in vivo, and CSF flow at the spinal cervical level, respectively. The novelty of the method lies in the model mathematics that predicts CSC distribution (that obeys the physical laws) from the system dc gain of the discrete-domain transfer function. 104 healthy individuals (48 males, 56 females, age 25.4 ± 14.9 years, range 3-60 years) without any history of neurological diseases, were used in the study. Non-invasive MR assisted estimate of ICP was calculated and compared with the cranial compliance to prove our hypothesis. RESULTS: A significant negative correlation was found between model-predicted cranial contribution to CSC and MR-ICP. The spinal canal provided majority of the compliance in all the age groups up to 40 years. However, no single sub-compartment provided majority of the compliance in 41-60 years age group. The cranial contribution to CSC and MR-ICP were significantly correlated with age, with gender not affecting the compliance distribution. Spinal contribution to CSC significantly positively correlated with CSF stroke volume. CONCLUSIONS: This paper describes MRI-based non-invasive way to determine the cranio-spinal compliance distribution in the brain and spinal canal sub-compartments. The proposed mathematics makes the model always stable and within the physiological range. The model-derived cranial compliance was strongly negatively correlated to non-invasive MR-ICP data from 104 patients, indicating that compliance distribution plays a major role in modulating ICP.

[The spinal dural arteriovenous fistula is an underdiagnosed vascular malformation].

The spinal dural arteriovenous fistula is the most common spinal vascular malformation, and it is severely underdiagnosed. The symptoms can mimic those of spinal stenosis. Today, the diagnosis is made by an advantageous combination of MR time-resolved imaging of contrast kinetics and digital subtraction angiography posing low risk to the patient. Treatment is primarily direct microsurgical obliteration. Early treatment is essential, since outcome is dependent on preoperative clinical status.

Three-dimensional visualization of internal vertebral venous plexuses relative to dural sac and spinal nerve root of spinal canal stenosis using MRI.

PURPOSE: The aim of this study was to introduce a new method of producing three-dimensional (3D) images of vertebral venous plexuses (VVPs) by 3D-MRI with and without contrast media, to identify pathoanatomical features that might accelerate or modify spinal canal stenosis. METHODS: We used a 1.5-T MRI unit with two different 3D sequences with and without contrast media. Multi planar reconstruction (MPR) images of VVPs could be obtained by volume image subtraction methods with a workstation for dural sac from whole 3D volume MPR without contrast media, using images before and after gadoteridol injection. Three patients with degenerative lumbar spine disease and one with cervical ossification of the posterior longitudinal ligament (OPLL) were studied with and without contrast media. As three patients underwent operations, we investigated intraoperative microscopic findings, and compared VVP images. RESULTS: Abundant components of internal VVPs were identified on MRI in correlation with neural tissues such as dura and nerve roots. CONCLUSIONS: Using 3D MRI without and with gadoteridol, we can evaluate morphological changes in VVP under degenerative spinal conditions. The MR anatomy of VVPs of the spine is important, as it has been implicated in many pathophysiological mechanisms and may also cause pitfalls in MRI.

A New Type of Spinal Epidural Arteriovenous Fistulas Causes Spinal Epidural Hemorrhage: An Analysis of Five Cases and Natural History Consideration.

BACKGROUND: Spinal epidural arteriovenous fistulas (SEDAVFs) are peculiar and poorly understood lesions with a poorly understood natural history. They usually are subclassified into 2 types according to their drainage components. This study aimed to describe a new type of SEDAVFs that is featured with a unique drainage pattern and present our natural history hypothesis of SEDAVFs. METHODS: Five SEDAVF cases of the new type were reviewed retrospectively from a high case-volume spinal vascular malformation database. The clinical manifestations, neuroradiologic findings, angioarchitecture, treatment strategies, and clinical outcomes were assessed. RESULTS: All patients presented with spontaneous spinal epidural hematoma, and 2 of them exhibited rebleeding. The median age at the initial episode was 20 years. Spinal digital subtraction angiography revealed slow-flow epidural fistulas drained by spinal epidural venous plexus without intradural drainage or engorged venous pouches in all 5 patients. Three patients underwent microsurgical treatment. The outcomes of all of the patients were favorable. CONCLUSIONS: Our study reported a special type of hemorrhagic SEDAVF without an intradural drainage component or epidural mass effect. The key diagnostic clue was early opacification of spinal epidural venous plexus on spinal angiogram. We believe SEDAVFs may form at an early age and gradually develop with time. Different types of SEDAVFs may represent different developing stages of one disease, and our type may represent the early stage of SEDAVFs.

Computed tomographic and angiographic assessment of spinal extradural arteriovenous fistulas in a dog.

A 6-month-old German shepherd dog was presented for progressive paraparesis. Multiple arteriovenous fistulae and hyperostosis of the thoracic vertebrae with secondary thoraco-lumbar spinal cord compression were diagnosed. Arteriovenous spinal fistula is a rare condition but should be considered as a differential diagnosis in young dogs with progressive paraparesis.

Évaluation par tomodensitométrie et angiographie de fistules artérioveineuses extradurales spinales chez un chien. Un chien Berger allemand âgé de 6 mois a été présenté pour une paraparésie progressive. De nombreuses fistules artérioveineuses et de l'hyperostose des vertèbres thoraciques avec une compression de la colonne vertébrale thoraco-lombaire secondaire ont été diagnostiquées. Les fistules spinales artérioveineuses sont une rare affection mais elles devraient être considérées comme un diagnostic différentiel chez les jeunes chiens atteints de paraparésie progressive.(Traduit par Isabelle Vallières).

The post-occipital spinal venous sinus of the Nile crocodile Crocodylus niloticus: its anatomy and use for blood sample collection and intravenous infusions.

The post-occipital sinus of the spinal vein is often used for the collection of blood samples from crocodilians. Although this sampling method has been reported for several crocodilian species, the technique and associated anatomy has not been described in detail in any crocodilian, including the Nile crocodile (Crocodylus niloticus). The anatomy of the cranial neck region was investigated macroscopically, microscopically, radiographically and by means of computed tomography. Latex was injected into the spinal vein and spinal venous sinus of crocodiles to visualise the regional vasculature. The spinal vein ran within the vertebral canal, dorsal to and closely associated with the spinal cord and changed into a venous sinus cranially in the post-occipital region. For blood collection, the spinal venous sinus was accessed through the interarcuate space between the atlas and axis (C1 and C2) by inserting a needle angled just off the perpendicular in the midline through the craniodorsal cervical skin, just cranial to the cranial borders of the first cervical osteoderms. The most convenient method of blood collection was with a syringe and hypodermic needle. In addition, the suitability of the spinal venous sinus for intravenous injections and infusions in live crocodiles was evaluated. The internal diameter of the commercial human epidural catheters used during these investigations was relatively small, resulting in very slow infusion rates. Care should be taken not to puncture the spinal cord or to lacerate the blood vessel wall using this route for blood collection or intravenous infusions.

Insights into cerebrospinal fluid and cerebral blood flows in infants and young children.

This study investigates the craniospinal flows of blood and cerebrospinal fluid using phase-contrast magnetic resonance imaging (MRI) on 23 control neonates and infants (5 d-68 mo old). Mean arterial cerebral blood flow increased with age of infant from 180 mL/min after birth to 1330 mL/min around 6 years of age. This corresponds to 51 mL/min/100 g and 95 mL/min/100 g, respectively. Cervical cerebrospinal fluid stroke volume increased from 38 × 10(-3) mL to 752 × 10(-3) mL per cardiac cycle. After arterial systolic blood inflow, we observed a delay of the venous outflow that was always preceded by cerebrospinal fluid flushing out through the spinal canal. These results highlighted the importance of compliance of the spinal compartment and the interaction of blood and cerebrospinal fluid dynamics. The capacity of the spinal compartment to receive intracranial cerebrospinal fluid in presence of fontanels was demonstrated. We provide reference values to understand the physiology of cerebrospinal fluid and cerebral blood.

Paraspinal arteriovenous fistula presenting with subarachnoid hemorrhage and acute progressive myelopathy--case report.

A 60-year-old man presented with paraspinal arteriovenous fistula (AVF) manifesting as subarachnoid hemorrhage (SAH) and acute progressive myelopathy. The patient presented with sudden onset of low back pain and paraparesis. Spinal magnetic resonance imaging revealed a vascular malformation on the lumbar spinal canal. Three-dimensional computed tomography angiography demonstrated a paraspinal AVF in the sacral ventral pelvis. The clinical symptoms were progressing rapidly, so transarterial embolization and surgical drainage ligation were performed. Paraspinal AVF may present with SAH and cause acute progressive myelopathy. Prompt examination and treatment are necessary.

Characteristic features of a nerve primo-vessel suspended in rabbit brain ventricle and central canal.

Bonghan theory was proposed by Bonghan Kim to illustrate the anatomy and physiology of the acupuncture meridian system. One of his astonishing claims was the physical presence of the nerve primo-vessel, which can be involved with a regenerating system of nerves. Our previous work has shown that there is a nerve primo-vessel in brain ventricles and the central canal of the spine of a rabbit. In this study, confocal laser scanning microscopy, transmission electron microscopy, and high voltage electron microscopy demonstrated that a nerve primo-vessel comprised DNA particles, other microparticles, and rod-shaped nuclei encircled by helix-shaped actins. The nerve primo-vessel had acridine orange-stained DNA particles that varied in size and were in parallel. These characteristics of the nerve primo-vessel are crucial for a comprehensive understanding of their function in the central nervous system, which may be associated with nerve regeneration.

Spinal accessory nerve cavernous malformation.

We present the first reported case of a spinal accessory nerve cavernous malformation. A 54-year-old Caucasian male presented with a several-year history of progressive, vague bilateral upper and lower extremity paresthesias and pain. MRI of the spine revealed a heterogenously enhancing mass in the dorsal aspect of the spinal canal at the level of the atlas with mild spinal cord compression. The lesion was resected and upon gross and histologic examination it was a cavernous malformation embedded within a branch of the spinal accessory nerve. Post-operatively, the patient had no complications and some improvement in his symptoms. To our knowledge, this is the first report of a patient with a spinal accessory nerve cavernous malformation, and this should be considered in the differential of lesions in the craniocervical region.

The vascular anatomy of the vertebro-spinal axis.

This article discusses the vascular anatomy of the vertebra-spinal axis and covers such topics as vascular supply to the spine, spinal dura, and paraspinal musculature; vascular supply to the spinal cord; and spinal veins.

Usefulness of three-dimensional digital subtraction angiography in endovascular treatment of a spinal dural arteriovenous fistula.

The use of 3D digital subtraction (DS) angiography provides a better understanding of spinal vascular lesion architecture. The authors report on 2 cases involving a spinal dural arteriovenous fistula (DAVF) and demonstrate the usefulness of 3D DS angiography for endovascular treatment of these spinal DAVFs. In both cases, middle-aged male patients suffered from bilateral leg hypesthesia, gait disturbance, and urinary dysfunction several months before treatment. Spinal angiography revealed DAVFs that were fed by a radicular artery branching from the intercostal artery and draining veins proceeding superiorly along the perimedullary veins. Endovascular embolization was performed in both cases. Selective 3D DS angiography of the intercostal artery clearly demonstrated the tortuous course of the feeder and the relationship among the feeding artery, fistula point, and draining veins in each case. This information was very useful in selecting a working angle for manipulating the microcatheter and for glue injection. In addition, the maximum intensity projection image from rotational DS angiography data clearly showed the fistula point at the dural sleeve and feeder entering the spinal canal via the intervertebral foramen and the relationship with the bone structure. Successful obliteration of the fistulae was achieved in both cases. Selective spinal 3D DS angiography was very useful in understanding the complex spinal vascular architecture and in choosing the best working angle and therapeutic strategy for endovascular treatment of spinal DAVFs.

Thoracic spine extradural arteriovenous fistula: case report and review of the literature.

BACKGROUND: Spinal extradural arteriovenous fistula is a rare, disabling, but potentially treatable disease. Only 27 cases have been reported so far in the past 40 years. CASE DESCRIPTION: An 18-year-old adolescent girl developed repeated back pain and mild paraplegia after a training course. Magnetic resonance imaging revealed a vessel-like lesion at the spinal extradural space, compressing the spinal medulla at the T5 level. Angiography disclosed a focal fistula fed by branches of the intercostal artery. The vascular mass was surgically removed and confirmed pathologically. CONCLUSION: Spinal extradural arteriovenous fistulas have an arterial supply that originates outside the spinal dura, with venous draining into the spinal extradural venous plexus. They may lead to myelopathy, radiculopathy, or spontaneous extradural hematoma, due to dilated vein compression, blood stealing, or spinal venous hypertension. Extradural hematoma needs emergency laminectomy and clot evacuation. And extradural arteriovenous fistulas should be treated actively by embolization, surgical resection, or both. Appropriate treatment will stabilize the patient or result in neurological improvement.

Spontaneous spinal subarachnoid hemorrhage secondary to spinal aneurysms: diagnosis and treatment paradigm.

INTRODUCTION: Isolated spinal aneurysms are rare; only a few have been reported. To the best of our knowledge, this series represents the largest experience with four ruptured spinal aneurysms, all of which were treated surgically. METHODS: Clinical information from the hospital charts and diagnostic images of four patients with the diagnosis of spinal aneurysms were reviewed from the senior authors' (RFS, JMZ) office database, surgical reports, and radiological imaging database. Follow-up examinations were performed by phone interview, when possible, and by chart review. RESULTS: Between 1997 and 2004, four patients with ruptured spinal aneurysms underwent surgical treatment. All aneurysms were located within the spinal canal and manifested with spinal subarachnoid hemorrhage. No collagen disease, aortic coartaction, arteriovenous fistula, or arteriovenous malformations were identified in these patients. CONCLUSION: Subarachnoid hemorrhage within the spinal cord can be caused by ruptured aneurysms. Spinal aneurysms are rare, but should be considered within the differential diagnosis of patients with intracranial subarachnoid hemorrhage when cranial angiography is negative. Magnetic resonance imaging and selective spinal angiography are useful for workup, but definitive diagnosis may require surgical exploration.

Evaluation of the internal vertebral venous plexus, vertebral canal, dural sac, and vertebral body via nonselective computed tomographic venography in the cervical vertebral column in healthy dogs.

OBJECTIVE: To evaluate nonselective computed tomographic (CT) venography for evaluating the cervical internal vertebral venous plexus (IVVP), define the diameter and area dimensions of the IVVP, and determine the relationship between dimensions of the cervical IVVP and other vertebral components in medium-sized dogs. Animals-6 healthy dogs that weighed 18 to 27 kg. Procedure-Helical CT scans were performed from C1 to C7 before and after IV injection of contrast medium (480 mg of iodine/kg) and a continuous infusion (240 mg of iodine/kg). Image data were transferred to a CT workstation, and measurements were performed on displayed transverse images. Diameter and area measurements of the vertebral canal, dural sac, IVVP, and vertebral body were obtained at C3 to C7. RESULTS: Opacification of vertebral venous structures was achieved in all dogs with no adverse reactions. Sagittal diameters of the IVVP for C3 to C7 ranged from 0.6 to 3.2 mm. Transverse diameters ranged from 2.32 to 5.74 mm. The IVVP area represented 12.4% of the mean vertebral canal transverse area and 30.61% of the mean vertebral epidural space area. Area measurements of the IVVP were significantly correlated with vertebral canal area and dural sac area. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that nonselective CT venography is a safe, sensitive method for performing morphometric assessments of the cervical IVVP in dogs. Findings support the theory that there may be a physiologic or developmental relationship between cervical vertebral canal components.

Ectopic firing due to artificial venous stasis in rat lumbar spinal canal stenosis model: a possible pathogenesis of neurogenic intermittent claudication.

STUDY DESIGN: An electrophysiologic analysis was performed on a chronic lumbar spinal stenosis model of rats. The effects of venous stasis on ectopic firing originating in the nerve root were investigated. OBJECTIVES: To elucidate the mechanisms of neurogenic intermittent claudication in lumbar spinal canal stenosis. SUMMARY OF BACKGROUND DATA: Neurogenic intermittent claudication has been known as a characteristic symptom of lumbar spinal canal stenosis (LSCS), but the pathogenesis is poorly understood. Venous stasis of cauda equina has been speculated as a possible factor in the development of symptoms of the lower extremities while walking. On the other hand, ectopic firing originating in the dorsal root ganglia is thought to play an important role in the development of radicular pain or abnormal sensation. However, a direct association between venous stasis and ectopic firing has been never demonstrated. METHODS: Using 10 Wistar rats, the LSCS group was prepared by inserting two silicone strips into the L3 and L5 dorsal epidural spaces. Another 10 animals were treated without silicone insertion as a sham group. Fourteen days later, the ectopic firing originating in the L5 nerve root was antidromically recorded from the distal stump of the severed sural nerve. After recording initial spontaneous firing, the posterior vena cava was clamped for 60 seconds to simulate a transient venous stasis and the changes in firing were analyzed. RESULTS: None of the animals in the sham group showed a significant change in firing due to venous stasis. In contrast, most animals in the LSCS group showed a marked increase in firing during the venous stasis with some latency and then returned to the initial firing state after the release of the clamp. This phenomenon was repeated as long as the animals were maintained. CONCLUSIONS: We demonstrated that ectopic firing was elicited by venous stasis only in the LSCS animals. Therefore, the venous stasis may be a major factor of neurogenic intermittent claudication.

[MR appearance of the spinal canal vascular malformations]. / Malformacje naczyniowe kanalu kregowego w obrazach MR.

Vascular malformations of the spinal canal are rare and their clinical appearance is not specific. The authors demonstrate material of 6 patients, who have been diagnosed with magnetic resonance imaging (MR). MR studies in all cases showed tortuous foci of very low signal, compatible with pathological vessels. In 2 patients malformations were also visible on MR angiography and confirmed with conventional angiography. Besides, in 2 cases features of secondary spinal cord oedema (thickening and hyper-intensity on T2-weighted images) have been shown. One patient had spinal cord haematoma which was not visible on MR and has been diagnosed with computed tomography (CT). In the authors' opinion MR is an efficient method of diagnosing and evaluating spinal canal vascular malformations and should be the first diagnostic study in these cases.