Spontaneous infarction of lumbar roots, vertebrae and paravertebral muscles.

Ischemic injury to the lumbosacral nerve roots and plexus is a rare condition resulting from thrombosis of one or several lumbar arteries. As the arterial supply of the spine presents great variations between subjects, the clinical presentation of lumbar thrombosis is highly variable depending on the relative involvement of nerve roots, bones or muscles. Diagnosis can be challenging, especially in the acute phase, as different structures can be simultaneously involved. The identification of an enlarged vessel centered in the area of tissue damage can help with the final diagnosis. We present the case of a 59-year-old woman who presented with spontaneous incomplete cauda equina syndrome due to diffuse lumbar nerve root infarction. On imaging, acute lumbar artery thrombosis was confirmed, and in addition to nerve roots, adjacent vertebral and paraspinal muscle infarctions were also present.

Conus Medullaris Infarction Involving the Paraspinal Muscles and Nerve Roots.

Spinal cord infarctions account for less than 1% of all strokes. The segmental artery supplies the spinal cord, vertebrae, nerve roots, and paraspinal muscles. To our knowledge, this is the first case of spinal cord infarction involving multiple distinct infarcts at various sites, including the lumbar vertebrae, conus medullaris, dorsal thoracolumbar spinal cord, paraspinal muscles, and nerve roots.

Intradural radicular arteriovenous fistula that mimics dural arteriovenous fistula: report of three cases.

We herein present three cases of a rare type of spinal AVF, an intradural radicular AVF, which mimicked a dural AVF. A 65-year-old male presented with congestive myelopathy. On angiography, right vertebral angiogram (VAG) showed a suspected dural AVF; however, left VAG showed the same intradural dilated vein fed by the anterior spinal artery (ASA). Intraoperative and histological results suggested that a single AVF was located on the right C1 nerve root fed by the right C1 radicular artery and branch of the anterior spinal artery. Two additional patients with a radicular AVF at the C3 or C5 level were presented. Intradural radicular AVFs and dural AVFs have very similar appearances; however, there is a difference that makes the risk of the endovascular treatment of radicular AVFs markedly higher because of blood supply from the ASA. In our case, the AVF was completely occluded by direct surgery without major complications.

Distribution Patterns of Vasculature Around Cervical Nerve Roots.

BACKGROUND: To the authors' knowledge, there has not been an ultrasound study of the vulnerable vessels in a C3-7 cervical nerve root block (CNRB). OBJECTIVES: To evaluate the prevalence of vulnerable vessels around the target of a CNRB at the cervical nerve root of C3-7 levels in a clinical setting. DESIGN: Retrospective, cross-sectional study. SETTING: General teaching hospital, rehabilitation unit. PARTICIPANTS: A total of 104 patients complaining of neck or arm pain with no prior surgical history and who had undergone a CNRB at an outpatient clinic from May 2015 to December 2017 were included. MAIN OUTCOME MEASUREMENTS: The prevalence of vulnerable vessels as seen on a preprocedure ultrasound scan around the target of a CNRB at the cervical nerve root of C3-7 levels. RESULTS: Out of 104 cases, the C3 level had 7 blood vessels (8.33%), the C4 level had 14 blood vessels (13.86%), the C5 level had 17 blood vessels (16.35%), the C6 level had 27 blood vessels (25.96%), and the C7 level had 31 blood vessels (29.81%) either at the targeted cervical nerve root or at the site of the imaginary needle's projected pathway to the targeted cervical nerve root. CONCLUSION: There was a substantial prevalence of vulnerable vessels either at the targeted nerve root or at the site of the needle's projected pathway to the nerve root.

Microanatomy of the brachial plexus roots and its clinical significance.

PURPOSE: To provide the anatomical basis of brachial plexus roots for the diagnosis and treatment of brachial plexus root avulsion injury. METHODS: The morphological features of brachial plexus roots were observed and measured on 15 cervicothoracic spine of adult cadavers. The relationship of brachial plexus nerve roots and the surrounding tissues also were observed, as well as the blood supply of anterior and posterior roots of the brachial plexus. RESULTS: Origination of the nerve roots in the dorsal-ventral direction from the midline was fine-tuned at each level along the spinal cord. The minimum distance of the origin of the nerve root to midline was 2.2 mm at C 5, while the maximum was 3.1 mm at T 1. Inversely, the distance between the origin of the posterior root and the midline of the spinal cord gradually decreased, the maximum being 4.2 mm at C 5 and minimum 2.7 mm at T 1. Meanwhile, there was complicated fibrous connection among posterior roots of the brachial plexus. The C 5-6 nerve roots interlaced with tendons of the scalenus anterior and scalenus medius and fused with the transverse-radicular ligaments in the intervertebral foramina. However, these ligaments were not seen in C 7-8, and T 1. The blood supply of the anterior and posterior roots of the brachial plexus was from the segmental branches of the vertebral artery, deep cervical artery and ascending cervical artery, with a mean outer diameter of 0.61 mm. CONCLUSIONS: The systematic and comprehensive anatomic data of the brachial plexus roots provides the anatomical basis to diagnose and treat the brachial plexus root avulsion injury.

High cervical arteriovenous fistulas fed by dural and spinal arteries and draining into a single medullary vein: report of 3 cases.

OBJECT: The authors previously reported a case of complex arteriovenous fistula (AVF) at C-1 with multiple dural and spinal feeders that were linked with a common medullary venous channel. The purpose of the present study was to collect similar cases and analyze their angioarchitecture to gain a better understanding of this malformation. METHODS: Three such cases, affecting 2 males and 1 female in their 60s who had presented with hematomyelia (2) or progressive myelopathy (1), were treated surgically, and the operative findings from all 3 cases were compared using digital subtraction angiography (DSA) to determine the angioarchitecture. RESULTS: The C-1 and C-2 radicular arteries and anterior and posterior spinal arteries supplied feeders to a single medullary draining vein in various combinations and via various routes. The drainage veins ran along the affected ventral nerve roots and lay ventral to the spinal cord. The sites of shunting to the vein were multiple: dural, along the ventral nerve root in the subarachnoid space, and on the spinal cord, showing a vascular structure typical of dural AVF, that is, a direct arteriovenous shunt near the spinal root sleeve fed by one or more dural arteries and ending in a single draining vein, except for intradural shunts fed by feeders from the spinal arteries. In 2 cases with hemorrhagic onset the drainer flowed rostrally, and in 1 case associated with congestive myelopathy the drainer flowed both rostrally and caudally. Preoperative determination of the shunt sites and feeding arteries was difficult because of complex recruitment of the feeders and multiple shunt sites. The angioarchitecture in these cases was clarified postoperatively by meticulous comparison of the DSA images and operative video. Direct surgical intervention led to a favorable outcome in all 3 cases. CONCLUSIONS: A high cervical complex AVF has unique angioarchitectural characteristics different from those seen in the other spinal regions.

A microchannel neuroprosthesis for bladder control after spinal cord injury in rat.

A severe complication of spinal cord injury is loss of bladder function (neurogenic bladder), which is characterized by loss of bladder sensation and voluntary control of micturition (urination), and spontaneous hyperreflexive voiding against a closed sphincter (detrusor-sphincter dyssynergia). A sacral anterior root stimulator at low frequency can drive volitional bladder voiding, but surgical rhizotomy of the lumbosacral dorsal roots is needed to prevent spontaneous voiding and dyssynergia. However, rhizotomy is irreversible and eliminates sexual function, and the stimulator gives no information on bladder fullness. We designed a closed-loop neuroprosthetic interface that measures bladder fullness and prevents spontaneous voiding episodes without the need for dorsal rhizotomy in a rat model. To obtain bladder sensory information, we implanted teased dorsal roots (rootlets) within the rat vertebral column into microchannel electrodes, which provided signal amplification and noise suppression. As long as they were attached to the spinal cord, these rootlets survived for up to 3 months and contained axons and blood vessels. Electrophysiological recordings showed that half of the rootlets propagated action potentials, with firing frequency correlated to bladder fullness. When the bladder became full enough to initiate spontaneous voiding, high-frequency/amplitude sensory activity was detected. Voiding was abolished using a high-frequency depolarizing block to the ventral roots. A ventral root stimulator initiated bladder emptying at low frequency and prevented unwanted contraction at high frequency. These data suggest that sensory information from the dorsal root together with a ventral root stimulator could form the basis for a closed-loop bladder neuroprosthetic.

Optimal technique of three-dimensional MRI of the lumbar nerve root and its radicular vein in normal and lumbar disc herniation patients.

BACKGROUND: Although three-dimensional MRI (3D-MRI) of short T1 inversion recovery turbo spin-echo (STIR TSE) has showed superior to two-dimensional MRI (2D-MRI) in showing the spinal cord and lumbar nerve roots, it remains difficult in demonstrating radicular vein at present. We have found that short T1 inversion recovery long time echo (STIR LONG TE) was better in showing radicular vein. To further study the methods and character of the 3D-MRI of lumbar nerve root, ganglions and radicular vein in normal and lumbar disc herniation (LDH) adults, in the present study, we evaluated two 3D-MRI techniques, STIR TSE and STIR LONG TE for demonstrating lumbar nerve roots and especial radicular vein in normal and LDH adults. METHODS: Twelve normal adult persons and 19 LDH patients were included in this study; special oblique coronal location was adopted. STIR TSE and STIR LONG TE were performed in all participants, and the detection rates of radicular vein and nerve root of L3, L4, L5, S1 were calculated. The grading system was used in grading compromise of the intraspinal extradural lumbar nerve root, ganglion and radicular vein in LDH patients, and all the grading injury of nerve root, ganglion and radicular vein had been evaluated. RESULTS: The definite rate of radicular vein (DRRV) of 3D-MRI of STIR LONG TE was significantly different from that of STIR TSE. DRRV of STIR LONG TE was L3, 91.7%, L4, 100%, L5, 100%, S1, 100% and that of STIR TSE was L3, 33.3%, L4, 37.5%, L5, 58.3%, S1, 45.8% in normal adults. It showed no difference between STIR LONG TE and STIR TSE in the detection rate of nerve root. The different patho-injuries of nerve root, ganglion and radicular vein could be seen in all LDH patients by the 3D-MRI of STIR LONG TE. The mean score of Japanese Orthopaedic Association (JOA) was 16.16, and 29 nerve roots were calculated in all the study. The mean grading injury of nerve root was 2.17, that of nerve root ganglion was 1.28, that of radicular vein was 1.83, and the mean co-grading injury of nerve root, ganglion and radicular vein was 5.31. The correlation coefficient was 0.478 (P = 0.010) between the score of JOA and that of radicular vein. CONCLUSION: The 3D-MRI of STIR LONG TE is superior to STIR TSE for not only detecting the lumbar nerve root, ganglion and especial radicular vein in normal adults, but also displaying their patho-injuries degree in LDH patients.

Arteriovenous fistula in a nerve root of the cauda equina fed by a proximal radiculo-medullary artery: a report of two cases.

While there have been a few reports on cases of intradural spinal arteriovenous fistula located on the filum terminale, no cases of its location in a nerve root of the cauda equina have been reported to date.We describe two such cases and describe the intraoperative findings. A 40-year-old man presented weakness of his left leg. Another 62-year-old man presented paraparesis dominantly in his left leg with urinary hesitation. In both cases, spinal T2-weighted magnetic resonance images showed edema of the spinal cord, indicating a flow void around it. Digital subtraction angiography disclosed an anterior radicular artery branching from the anterior spinal artery on the surface of the conus medullaris and a turnaround vein running in the opposite direction within the cauda equina. In the first patient, while the feeding artery running along a nerve root was detected, the draining vein and the fistula were not identified at first sight. An incision into the respective nerve root exposed their location within it. In the second patient, unlike the first case, the feeding artery and the fistula were buried in a nerve root, while the draining vein was running along the nerve's surface. In both cases, permanent clips were applied to the draining vein closest to the fistula. The recognition of a hidden fistulous point in a nerve root of the cauda equina is essential for successful obliteration of the fistula.

Increased expression of vascular endothelial growth factor protein in dorsal root ganglion exposed to nucleus pulposus on the nerve root in rats.

STUDY DESIGN: An experimental rat study. OBJECTIVE: To assess pain-related behavior and vascular endothelial growth factor (VEGF) expression induced by nucleus pulposus (NP) applied to nerve roots in rats. SUMMARY OF BACKGROUND DATA: Radiculopathy from disc herniation is caused by nerve compression and chemical inflammation. In experimental studies, a decrease in mechanical withdrawal threshold, blood flow, and nerve root dysfunction was reported when the NP was applied to nerve roots. However, neuron reproduction and changes in nerve root blood vessels have not been clearly understood. METHODS: NP harvested from the tail was applied to the left L5 dorsal root ganglion (NP group; n = 77). As a control, sham-operated animals were used (n = 77). Behavioral testing with von Frey hairs was performed for 35 days. Immunoreactivity (IR) for VEGF, activating transcription factor-3, growth-associated protein-43 (GAP-43), factor VIII, and hypoxia-inducible factor-1[alpha] (HIF-1 a) were studied by immunohistochemistry. Western blot analyses of VEGF and GAP-43 were also performed. RESULTS: The mechanical withdrawal threshold significantly decreased from 7 to 28 days in the NP group versus the sham group (P < 0.05). In the NP group, activating transcription factor-3-IR cells increased from 3 to 14 days (P < 0.05), hypoxia-inducible factor-1[alpha]-IR cells increased at 14 days (P < 0.05), and blood vessels with Factor VII-IR cells increased at 28 days (P < 0.05) compared with the sham group. The expression levels of VEGF and GAP-43 in the NP group significantly increased at 14 and 28 days (P < 0.05). CONCLUSION: Neuron damage induced by NP applied to the nerve root at the early stage, and axon extension occurred from 14 days. VEGF increased at 14 and 28 days, and the numbers of blood vessels increased 28 days after surgery. The mechanical withdrawal threshold improved at 35 days. Regeneration and vascularization by VEGF might be associated with pain-related behavior.

Vasculature and neurovascular relationships of the trigeminal nerve root.

BACKGROUND: Specific microanatomical characteristics of the trigeminal nerve root (TNR) blood supply and close neurovascular relationships with surrounding vessels as well as their possible clinical significance were the main reasons for this study. METHOD: The vasculature of 25 adult and four fetal TNRs were microdissected and examined under the stereoscopic microscope, after injecting their arteries with India ink. RESULTS: The trigeminal vessels, which varied between two and five in number, arose from two or three of the following arteries: the superolateral pontine (92%), anterior inferior cerebellar (AICA) (88%), inferolateral pontine (72%), and superior cerebellar (SCA) (12%). The trigeminal vascular twigs had a mean diameter of 0.215 mm. A single vessel may supply either the motor portion of the nerve root or the sensory portion or both. The trigeminal vasculature formed the proximal and distal rings. The proximal ring was located at the trigeminal root entry zone. Its central branches extended along the TNR to the principal sensory and motor trigeminal nuclei while its peripheral longitudinal twigs followed the TNR fascicles. The incomplete distal arterial ring embraced the middle portion of the TNR before the level of its entrance into the arachnoid sleeve. The most frequent contact of the TNR was noticed with the SCA (20%), the petrosal or Dandy's vein (24%), and the AICA (12%). CONCLUSIONS: The observed characteristics of the TNR vasculature could be the anatomical basis for decompressive neurovascular surgery.

Combined measurement of nerve root blood flow and electrophysiological values: intraoperative straight-leg-raising test for lumbar disc herniation.

STUDY DESIGN: A total of 15 patients with lumbar disc herniation at the L5-S1 disc level who underwent microendoscopic discectomy were examined. The nerve root blood flow and electrophysiological values were measured during an intraoperative straight-leg-raising (SLR) test. OBJECTIVE: To investigate the relationships between nerve root blood flow changes and the electrophysiological values during an intraoperative SLR test. SUMMARY OF THE BACKGROUND DATA: It is unknown how the electrophysiological values are affected by nerve root blood flow changes during an SLR test. METHODS: We measured S1 nerve root blood flow and electrophysiologically evaluated the nerve root using the compound muscle action potentials (CMAPs) from the gastrocnemius muscle after S1 nerve root stimulation during an intraoperative SLR test. Subsequently, we analyzed the relationships between the nerve root blood flow changes and the electrophysiological values. RESULTS: Before discectomy, there were sharp decreases in the nerve root blood flow after 1 and 3 minutes of the SLR test (P < 0.001), and the amplitudes of the CMAPs deteriorated significantly (P < 0.001). Significant correlations were found between the decrease ratio for the nerve root blood flow during the SLR test and the deterioration ratio for the amplitude of the CMAPs. After discectomy, the blood flow increased significantly (P = 0.001). When the SLR test was performed again, the blood flow showed no significant decreases. The average amplitudes of the CMAPs were significantly ameliorated (P < 0.01). When the SLR test was performed again, no significant differences were found for the average amplitudes after 1 and 3 minutes of the test. CONCLUSION: Significant correlations were found between the decrease ratio for the nerve root blood flow and the deterioration ratio for the amplitude of the CMAPs. The present results demonstrate that temporary ischemic changes in the nerve root cause transient conduction disturbances.

A macromolecular tracer indicates that the spinal epidural space connects directly to the venous circulation in pigs.

BACKGROUND AND OBJECTIVES: Air injected into the epidural space of the spine reaches the heart within 15 secs, suggesting easy access to the bloodstream. We wished to quantify the washout of a macromolecular tracer (albumin labeled with Evans blue) from the thoracic epidural space. METHODS: Eleven juvenile pigs were anesthetized with isoflurane and positioned on their sides. We injected a bolus of the tracer into the thoracic epidural space followed by serial saline infusions (total, 50-70 mL). We measured plasma concentrations of the tracer during washout. Finally, we injected Microfil (a liquid rubber compound that hardens on standing) into the epidural space and later inspected with a dissecting microscope the nerve roots and veins draining the spine. RESULTS: More than half (60% ± 12%; range, 31%-79%) of the tracer injected in the epidural space was detected in the bloodstream. Microfil was detected in the veins draining the cervical or high thoracic spine, but never in veins draining the lumbar spine or sacrum. CONCLUSIONS: Because the macromolecular tracer cannot enter the bloodstream by absorption, these results indicate that pathways capable of handling bulk flow connect the spinal epidural space to the venous circulation. These pathways are located in the cervical and high thoracic spine of the pig.

Microvascular system of the lumbar dorsal root ganglia in rats. Part I: a 3D analysis with scanning electron microscopy of vascular corrosion casts.

OBJECT: So far, the morphological features of the vascular system supplying the dorsal root ganglion (DRG) have been inferred only from microangiograms. However, in the past most of these studies lacked 3D observations. This study presents the details of the microvasculature of the lumbar DRG visualized by scanning electron microscopy of vascular corrosion casts. METHODS: Wistar rats were anesthetized with intraperitoneal sodium pentobarbital. After thoracotomy, the vascular system was perfused with heparinized saline, and Mercox resin was injected into the thoracic aorta. After polymerization of the resin, the vascular casts were macerated with potassium hydroxide, washed with water, and dried. The casts were examined with a scanning electron microscope. RESULTS: The vascular cast of the DRG was observed to have a higher density of vessels than the nerve root. Bifurcation or anastomoses of capillaries took place at approximately right angles, in a T-shaped pattern. Within the DRG, both the arterial supply and the capillary network contained blood flow control structures (ring-shaped constrictions in the cast probably representing a vascular sphincter in the microvessel). Three types of vessels could be distinguished: tortuous, straight, and bead-like capillaries. The dilations, bulges, and tortuousness of capillaries could serve the function of locally increasing the capillary surface area in a sensory neuron. CONCLUSIONS: The results of this study suggest a causal relationship between the metabolic demands of local neuronal activity and both the density of the capillary network and the placement of the blood flow control structures.

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.

Intratumoral hemorrhage of spinal schwannoma of the cauda equina manifesting as acute paraparesis--case report.

A 64-year-old man presented with spinal schwannoma of the cauda equina at the thoraco-lumbar junction manifesting as acute paraparesis and urinary incontinence after intratumoral hemorrhage. Surgical resection of the tumor resulted in significant neurological recovery. T(2)(*)-weighted gradient-echo magnetic resonance imaging is very useful to help establish the preoperative diagnosis, leading to early surgical intervention and better outcome after surgery.

Vasomotion of intraradicular microvessels in rat.

STUDY DESIGN: This study is to investigate the changes of vasomotion of intraradicular microvessels in vivo. OBJECTIVE: We have observed microvascular corrosion casts of the lumbar nerve root by scanning electron microscopy and used an immunohistochemical technique to investigate the presence and distribution of autonomic and sensory nerve in blood vessels of the nerve root. SUMMARY OF BACKGROUND DATA: It is generally considered that the genesis of radiculopathy associated with the degenerative conditions of the spine may result from both mechanical compression and circulatory disturbance. However, the neurogenic control of intraradicular blood flow has received little attention in the past. METHODS: For three-dimensional observation of intraradicular vessels, we used scanning electron microscopic examination of microvascular corrosion casts in ten Wister rats. To investigate the mechanism of vasomotion of the nerve root, we used immunohistochemical methods. The sections were incubated overnight with antisera to tyrosine hydroxylase, choline acetyl transferase, substance P, calcitonin-gene-related peptide, vasoactive intestinal peptide, somatostatin, neuropeptide Y, leucine-enkephalin, cholecystokinin octapeptide, brain-nitric oxide synthase, and endothelium-nitric oxide synthase. Abidin-biotin complex method was used as the immunohistochemical procedure and the sections were observed under the light microscope. RESULTS: The general view of whole vascular casts of the lumbar spinal cord and nerve roots showed a high density of vessels. Bifurcation or anastomoses of capillaries approximately took place at right angles in a T-shaped pattern and capillaries showed a lot of ring-like compressions. This ring-like compression on the cast may represent a vascular sphincter in the microvessels. This study also reveals the existence of perivascular adrenergic, cholinergic, peptidergic, and nitroxydergic innervation with a possible role in neurogenic regulation of nerve root circulation. CONCLUSION: Perivascular nerve plexuses around intraradicular microvessels suggest that the autonomic nerves play an important role in intraradicular circulation.

A unique vascular configuration among the efferent branchial arteries and splanchnic arteries in the yellow stingray, Urobatis jamaicensis.

With light and scanning electron microscopy of vascular corrosion casts, we have observed in Urobatis jamaicensis that the fourth epibranchial arteries do not merge completely with the dorsal aorta. Instead they form a brief anastomosis with a short vessel projecting ventrally from the dorsal aorta and maintain their integrity as separately distinct vessels. Posterior to the anastomosis, the right epibranchial becomes the celiac trunk and left epibranchial becomes the anterior mesenteric artery/posterior intestinal artery. This vascular configuration appears to be unique in elasmobranchs.