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At least 109 records · Page 6Linked to original sources
PubMed1991

Benign spinal nerve sheath tumors: their occurrence sporadically and in neurofibromatosis types 1 and 2.

Benign spinal nerve sheath tumors (neurofibromas and schwannomas) often occur on dorsal nerve roots sporadically or in neurofibromatosis types 1 and 2. These are histologically benign tumors, and distinction between them is frequently not made by clinicians. To determine if there is a correlation between the histological pattern of benign spinal nerve sheath tumors and the type of neurofibromatosis, the clinical and pathological features of these tumors (86 surgical specimens and five autopsies) in 68 patients were reviewed. The patients were classified into one of four categories: neurofibromatosis type 1, neurofibromatosis type 2, uncertain, or sporadic. The diagnostic criteria used for neurofibromatosis types 1 and 2 were established by the National Institutes of Health. Patients who did not fulfill criteria for either neurofibromatosis type 1 or 2 but who had multiple nervous system tumors or other stigmata of neurofibromatosis were designated "uncertain." Spinal nerve sheath tumors were considered sporadic in 42 cases (40 schwannomas and two neurofibromas). In the 14 patients with neurofibromatosis type 1, all spinal nerve sheath tumors were neurofibromas. In six of the seven patients with neurofibromatosis type 2, all spinal nerve sheath tumors were schwannomas. One patient with neurofibromatosis type 2 had a spinal nerve sheath schwannoma and a tumor with features of both tumor types. The authors conclude that spinal nerve sheath tumors in patients with neurofibromatosis type 1 are neurofibromas. In contrast, spinal nerve sheath tumors occurring in neurofibromatosis type 2 or sporadically are most frequently schwannomas. The distinct histological features of these tumors may reflect different pathogenetic mechanisms even though they arise at identical sites in neurofibromatosis types 1 and 2.

Humans↗
PubMed1993

The effects of induced hypertension and acute graded compression on impulse propagation in the spinal nerve roots of the pig.

Injuries caused by compression of spinal nerve roots are frequently encountered clinically. Experimental studies show that several different factors affect the pathophysiologic changes that occur after these injuries. However, the effect of hypertension in conjunction with graded compression of spinal nerve roots is yet unclear. A previously established porcine model was employed, in which the spinal nerve roots were exposed and compressed by an inflatable balloon. Impulse propagation across the compressed nerve segment was studied by the recording of efferent and afferent nerve action potentials, and nerve conduction velocity. The systemic blood pressure was increased by administration of Neo-Synephrine hydrochloride (phenylephrine HCl) (Winthrop Pharmaceuticals, New York, NY) and elevated 40 +/- 5 mm Hg above the normal (100 +/- 5 mm Hg), and electrophysiologic baseline values were recorded. The spinal nerve roots were then compressed for 2 hours with either 0 (control), 50, 100, or 200 mm Hg. The balloon was deflated and the nerve roots were allowed to recover for 1.5 hours. Impulse propagation was studied every 15 minutes and hypertension was maintained throughout the experiment. The results showed no significant changes of the efferent and afferent nerve action potentials at 0.50 or 100 mm Hg. At 200 mm Hg, efferent and afferent nerve action potentials decreased rapidly and were almost abolished within 20 minutes of compression. Some but not significant recovery was seen of the nerve impulse. Compared to data from normotensive pigs in an earlier experiment, the current study showed that hypertension significantly decreases the susceptibility of the spinal nerve roots to compression at and below 100 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1999

Behavioural measures of depression and anxiety in rats with spinal nerve ligation-induced neuropathy.

The behaviour of rats with spinal nerve ligation-induced neuropathic pain was studied using tests developed to measure depression and anxiety. Adult male Sprague-Dawley rats were tested with the open field test, elevated plus maze, two compartment test and forced swimming test. Spontaneous motility was measured in a photocell observation box. Mechanical sensitivity was tested with von Frey hairs and cold sensitivity with the acetone drop test. The L5-6 spinal nerves were ligated or a sham operation was performed and the rats were followed for 2 weeks before the same set of tests were repeated. Most of the neuropathy operated rats had mechanical and cold allodynia. With post-injury there was a significant decrease in the activity in the open field test and motility box tests, when compared with the pre-injury results. In the elevated plus maze test there was a significant reduction in the motility, but there was no change in the time spent in the closed wings. In the two compartment test there were no significant differences between the pre- and post-injury results. There were no differences between the rats with spinal nerve ligation injury and the sham operated rats in any of the tests. The results were also comparable when rats that developed a high degree of neuropathy were compared with the rats with low degree of neuropathy and the sham operated group. In conclusion, spinal nerve ligation injury of the spinal nerves L5-6 induces mechanical and cold allodynia, but it does not seem to produce general suffering or measurable anxiety to the animals. Furthermore, tests for anxiety and depression were not able to predict which animals were vulnerable to express symptoms of neuropathic pain after nerve injury.

Animals↗
PubMed2000

Recurrent (nonfamilial) hemangioblastomas involving spinal nerve roots: case report.

OBJECTIVE AND IMPORTANCE: Spinal nerve root hemangioblastomas are rare and are reported mainly in patients with von Hippel-Lindau (VHL) syndrome. The pathogenesis of so-called nonfamilial lesions is virtually unknown. We discuss, mainly from a molecular perspective, a unique patient with sporadic, recurrent hemangioblastomas restricted to spinal nerve roots. CLINICAL PRESENTATION: A 53-year-old man who had had a surgically corrected lumbosacral meningomyelocele presented on at least three occasions during a 17-year period with multifocal capillary hemangioblastomas involving spinal nerve roots. On each occasion, tumors appeared on a different nerve root, with the majority located in the midcervical segments. The patient had no clinical features or family history of VHL syndrome. TECHNIQUE: To obtain a clearer understanding of the pathogenesis of this unusual case and its relationship to VHL syndrome, molecular analysis of the VHL gene was performed by use of complete sequence analysis and loss of heterozygosity studies on deoxyribonucleic acid derived from the patient's blood leukocytes and three separately resected hemangioblastomas. CONCLUSION: Germ-line molecular analysis performed on all three exons in the VHL gene coding region did not indicate that any mutations were present. Loss of heterozygosity analysis of deoxyribonucleic acid from the three hemangioblastoma resections showed normal heterozygosity in the 3p25-26 region. Complete VHL gene sequence analysis did not demonstrate a somatic mutation in the coding region of the VHL gene in any of the three tumors, thereby supporting the loss of heterozygosity data that a molecular event directly involving the VHL gene may not be the causative factor in their tumorigenesis.

Base Sequence↗
PubMed1994

Experimental lumbar radiculopathy. Behavioral and histologic changes in a model of radicular pain after spinal nerve root irritation with chromic gut ligatures in the rat.

OBJECTIVE: The recently proposed animal model of lumbar radiculopathy was used to investigate behavioral consequences and histologic changes in spinal nerve roots, dorsal root ganglia, and spinal nerves after the L4, L5, and L6 nerve roots were loosely ligated with either silk or chromic gut sutures in an attempt to better understand the pathophysiologic mechanisms that give rise to pain associated with lumbar radiculopathy. SUMMARY OF BACKGROUND DATA: Little is known about the pathophysiologic mechanisms that give rise to pain associated with lumbar radiculopathy. The recently proposed animal model of unilateral lumbar radiculopathy, which demonstrated an association with motor paresis and thermal hyperalgesia of the affected hind limb and showed evidence of spontaneous pain has been demonstrated, may serve as a vehicle to allow direct investigation of the nature of the pathophysiological mechanisms associated with lumbar radiculopathy. METHODS: Three distinct treatments of the nerve roots were initially investigated: 1) a sham intervention, where the surgery simply exposed the nerve roots and dorsal root ganglion followed by standard closing procedures; 2) 4-0 silk ligature, where two loose ligatures of 4-0 silk were placed around the nerve roots; and 3) 4-0 chromic gut 2, where four 0.3 cm pieces of 4-0 chromic gut were laid adjacent to the nerve roots and secured by two loose ligatures of 4-0 chromic gut. STUDY DESIGN: ANOVA techniques were used to test for differential effects across time for the three treatment groups in terms of animal function. A qualitative analysis of the histology of the ipsilateral and contralateral nerve roots, dorsal root ganglia, and spinal nerves was done to correlate histologic changes with behavioral changes. RESULTS: Behavioral results were consistent with the previous study. Rats treated with chromic gut, but not silk, reliably demonstrated a prolonged thermal hyperalgesia that was maximal 2 weeks after surgery and lasted for up to 12 weeks. These behavioral changes, however, were not correlated with histologic changes in myelinated fiber content in the L4, L5, and L6 nerve roots, dorsal root ganglia and spinal nerves, the ipsilateral spinal nerved, dorsal root ganglia, and nerve roots of rates ligated with silk or chromic gut showed similar, significant, decreased in the number of large diameter myelinated fibers. CONCLUSIONS: These results suggest that mechanical constriction of the L4, L5, and L6 spinal nerve roots, as evidenced by a loss of myelinated fibers, is not sufficient to produce the behavioral effects associated with this model of lumbar radiculopathy. It is hypothesized that chemical factors from the chromic gut play a role in the pathophysiology and development of the behavioral, but not histological, changes in this model of lumbar radiculopathy.

Animals↗
PubMed2001

The effect of lumbar sympathectomy on increased tactile sensitivity in spinal nerve ligated rats.

The aim of this study was to investigate the reason for the contradictory results following surgical sympathectomy on increased tactile sensitivity in spinal nerve ligated rats. For this purpose, firstly the results of L5 spinal nerve ligation alone and both L5 and L6 (L5/6) spinal nerve ligation were compared in Sprague-Dawley rats. Secondly, the difference in tactile sensitivity between the plantar surface (the middle glabrous area on the foot pads of the hind paw) and on the toe (the proximal half of the third and fourth toe of the hind paw) after the spinal nerve injury was studied. Third, we divided the L5 spinal nerve ligated rats into two groups, (i.e. low and high threshold groups) based on the degree of tactile sensitivity and investigated the effect of surgical lumbar sympathectomy (L2-L5) on tactile sensitivity in both the plantar and toe areas. The results show that the tactile sensitivities of L5 spinal nerve ligated rats and L5/6 spinal nerve ligated rats were not different. However, tactile sensitivities of the plantar surface were less than those of toe area suggesting that the response from toe is a better indicator of neuropathic pain. Surgical sympathectomy reduced the response from only the toe area and only in the low threshold group. These results suggest that the reason for the contradictory results of surgical sympathectomy in spinal nerve ligation models is, at least in part, the difference in the degree of mechanical allodynia in each study.

Animals↗
PubMed1992

Proximal cervical spinal nerve: MR appearance.

An interradicular cleft and a segment of nerve containing fascicles have recently been described in the cervical spinal nerve. This study was performed to determine whether the fascicles and the interradicular cleft have a distinctive appearance on magnetic resonance (MR) images. The proximal spinal nerves and nerve roots of C-4 and C-8 were removed from cadavers, imaged with MR, sectioned, and stained. Cervical neural foramina were imaged with MR and then sectioned. The MR images demonstrated a division of the root sheaths into ventral and dorsal portions, separated by fat within the interradicular cleft and located proximal to the dorsal root ganglion. Distal to the dorsal root ganglion, the proximal portion of the cervical spinal nerve containing multiple fascicles gave the proximal portion of the spinal nerve an inhomogeneous appearance on the MR images. This study suggests an anatomic explanation for the variable appearance of the cervical spinal nerves with MR imaging.

Aged↗
PubMed1995

Contrast enhancement in spinal nerve roots: an experimental study.

PURPOSE: To examine histopathologically the endothelium of contrast-enhancing spinal nerve roots. METHODS: In five adult baboons, chronic compression of the left S-1 spinal nerve root sufficient to produce a change in the evoked potential was produced by means of a suture tied around the nerve. The animals were studied with MR at 8 and 16 days after nerve compression and then killed for histopathologic and electron microscopic studies. Histopathologic changes in the nerve roots demonstrating contrast enhancement were described. RESULTS: In all compressed spinal nerves, contrast enhancement was observed. Histopathologically, wallerian degeneration of the root and inflammation and disruption of the endothelium of capillaries in the spinal nerve were evident. CONCLUSIONS: Degenerative changes in the nerve root and the capillary endothelium of a lumbar spinal nerve are associated with contrast enhancement.

Animals↗
PubMed2006

The medial branch of the lateral branch of the posterior ramus of the spinal nerve.

UNLABELLED: In the needle insertion of epidural anesthesia with the paramedian approach, the needle can pass through the longissimus muscle in the dorsum of the patients. When the needle touches a nerve in the muscles, the patients may experience pain in the back. Obviously, the needle should avoid the nerve tract. To provide better anesthetic service, analysis of the structure and where the concerned nerves lie in that region is inevitable. MATERIAL AND METHOD: We studied five cadavers in this study. Two cadavers were fixed with Thiel's method. With these cadavers, we studied the nerve running of the posterior rami of the spinal nerve from the nerve root to the distal portion. Three of them were used for the study of transparent specimen, with which we studied the course and size of the nerve inside the longissimus muscle. RESULTS: We observed there were three branches at the stem of the posterior rami of the spinal nerves between the body segment T3 and L5, i.e. medial branch, medial branch of the lateral branch and lateral branch of the lateral branch. The medial branch of the lateral branch supplied to the longissimus muscle. With the transparent specimen, we found that there were different nerve layouts between the upper thoracic, lower thoracic, upper lumbar, and lower lumbar segments in the medial branch of the lateral branch in the longissimus muscle. In the lower thoracic and upper lumbar segments, the medial branch of the lateral branch of the upper lumbar segments produced layers nerve network in the longissimus muscle. L1 and L2 nerves were large in size in the muscle. CONCLUSION: In the upper lumbar segments the medial branch of the lateral branch of the posterior rami of the spinal nerve produced dense network in the longissimus muscle, where the epidural needle has high possibility to touch the nerve. Anesthetists have to consider the existence of the medial branch of the lateral branch of the posterior rami of the spinal nerve when they insert the needle in the paramedical approach to the spinal column.

Cadaver↗
PubMed1982

Spinal nerve root origins of the cutaneous nerves arising from the canine brachial plexus.

The spinal nerve root origins of the cutaneous nerves arising from the brachial plexus were investigated in 10 babiturate-anesthetized dogs by stimulating dorsal roots C5 to T2 and recording from each cutaneous nerve. Upon completion of the experiment, the contributions of the spinal nerve ventral branches to the brachial plexus were verified by anatomic dissection. The brachial plexus was formed by the ventral branches of C6 to T2 in 8 dogs, C6 to T1 in 1 dog, and C5 to T1 in 1 dog. The cutaneous branch of brachiocephalicus nerve was formed primarily by contributions from the C6 dorsal root. The cranial lateral cutaneous brachial nerve, a branch of the axillary nerve, was formed predominantly from C6 to C7. The median nerve received contributions primarily from C7, C8, and T1, and the communicating branch from the musculocutaneous to the median nerve contained fibers primarily from C7 and C8. The medial and lateral branches of the superficial branch of the radial nerve arose from C6, C7, C8, and T1, with the medial branch generally arising 1 segment craniad to the lateral. The palmar and dorsal branches of the ulnar nerve arose predominately from C8 and T1, and the caudal cutaneous antebrachial nerve of the ulnar arose predominately from T1 and T2.

Action Potentials↗
PubMed2000

Dorsal root section elicits signs of neuropathic pain rather than reversing them in rats with L5 spinal nerve injury.

Mechanical allodynia- and hyperalgesia-like behavior which develops in rats after L5 spinal nerve lesion has been suggested to be due to ectopic activity in the lesioned afferent neurons originating at the lesion site and/or in the dorsal root ganglion because it is eliminated by section of the dorsal root. Here we reevaluated the effect of a dorsal rhizotomy in rats after L5 spinal nerve lesion. Using calibrated von Frey hairs, paw withdrawal threshold to single stimuli and paw withdrawal incidence to repetitive stimulation were tested before and after nerve section. Neuropathic pain behavior of similar time course and magnitude also developed after cutting the L5 dorsal root, and L5 spinal nerve lesion-induced abnormal behavior could not be reversed by dorsal rhizotomy. The neuropathic pain behavior elicited by dorsal root section also developed when impulse conduction in the dorsal root axons was blocked during rhizotomy by a local anesthetic, i.e. when the immediate injury discharge was prevented from reaching the spinal cord. These results challenge the widely accepted idea that neuropathic pain behavior developing after spinal nerve lesion is dependent on ectopic activity in the lesioned afferent neurons. However, the present results do not rule out the possibility that after the two nerve lesions the mechanisms generating neuropathic pain behavior are different. After dorsal rhizotomy neuropathic pain behavior may be related to deafferentation whereas after spinal nerve lesion it may be caused by ectopic activity.

Animals↗
PubMed1984

Glial bundles in spinal nerve roots. An immunocytochemical study stressing their nonspecificity in various spinal cord and peripheral nerve diseases.

Glial bundles (GBs) in spinal nerve roots in 86 autopsy cases with various spinal lesions were examined using the peroxidase-antiperoxidase technique for glial fibrillary acidic protein (GFAP). In 19 of 22 cases of Werding-Hoffmann disease (WHD), GBs were present in the anterior roots (ARs) but absent in the youngest age group (age less than 1.5 months at death). GBs were numerous in classical cases (age 3-24 months), accompanying severe damage of the anterior horns and roots, but were less prominent in most cases of protracted course (age 2-8.5 years). Thus, development of GBs in the ARs of motor neuron disease at a young age seems to depend on the clinical type (age at onset and disease duration) and degree of damage to motor neurons and ARs. Varying numbers of GBs were found also in the posterior roots (PRs) of 12 cases of WHD. In 13 patients with amyotrophic lateral sclerosis (ALS), few GBs were observed in the ARs of two and PRs of five cases without apparent relation to other clinicopathologic data. GBs in the PRs of both WHD and ALS might indicate spreading of the degenerative process to sensory neurons despite the absence of pathology detectable by routine histological stains. Numerous GBs were found also in adults affected with polymyelitis in childhood. Varying numbers of GBs were present, however, in many different diseases, such as Friedreich ataxia, Guillain-Barré syndrome, various polyneuropathies, cervical spondylosis, ataxia telangiectasia, metachromatic leukodystrophy, and Leigh syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗