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PubMed2006

[Primitive malignant melanoma arising in a spinal nerve root. A case report].

We report the fourth case of primitive malignant melanoma arising in a spinal nerve root. A 39-year-old woman complained of one-year low back pain radiating to the right thigh and knee, and loss of 7 kg. Clinical examination found moderate quadricipital amyotrophy and hypoesthesia of anterior side of the thigh. MRI study demonstrated an enlargement of right L3 root with scalloping of the L3/L4 foramen. The T1-weighted MRI images showed a tumor hyperintensity, the T2-weighted images showed tumor isointensity and mild contrast enhancement. Due to the scalloping of L3/L4 foramen with root enlargement and slow evolution (more than one year between the first symptom and surgery without clinical worsening), the initial preoperative diagnosis was L3 schwannoma. After laminoarthrectomy and dural opening, a firm black lesion, well encapsulated and involved in a dorsal spinal root, was totally removed. The tumor was composed of irregular melanocytoid cells with high proliferation index (20%). Immunohistochemistry showed melanin, HMB-45 and S100 positivity, but reticulin was negative (that eliminates malignant melanocytic schwannoma). An extensive clinical and paraclinical research of other melanotic localisation was negative. So, the final diagnosis was intradural primitive malignant melanoma. Radiotherapy was performed on the site of the tumor. Fatal pulmonary metastasis occurred 18 months after surgery. The most common tumor with root enlargement and bony scalloping is the benign schwannoma. Despite the above described radiological features, MRI characteristics (hyperintensity when images are T1-weighted) suggest a melanocytic tumor, a tumor with a high adipose component or an intratumoral bleeding. Specific MRI sequences can eliminate adipose tissue tumor, but diagnosis between melanin and methemoglobin is still difficult. According to the index of proliferation, a primitive central melanocytic lesion can be a meningeal melanocytoma (considered as benign) or a primitive malignant melanoma. These tumors show identical protein expressions in immunohistochemistry, and their prognosis is very variable (some long-term remissions are reported for malignant melanomas and fast disseminations are described for meningeal melanocytomas treated by sub-total surgery). The L3/L4 foramen scalloping is unusual for a malignant lesion with theoretic high-speed development. The other 3 patients (reported in the literature) survive more than 3 years. The histological features of malignant lesion with benign clinical features lead to interrogation upon the actual pathologic classification.

Adult↗
PubMed1997

Effect of pulsed Nd:YAG laser radiation on action potential conduction in isolated mammalian spinal nerves.

BACKGROUND AND OBJECTIVE: Dental lasers are claimed to produce analgesia, but the mechanisms and extent of any effects are uncertain. This study investigated the effects of lasing on nerve conduction in isolated nerves. STUDY DESIGN/MATERIALS AND METHODS: Pulsed Nd:YAG laser energy was applied to spinal nerves in vitro and effects were measured as attenuation of the compound action potential (CAP) evoked by electrical stimulation. RESULTS: Lasing for 1 minute at 0.3-3.0 W caused a dose-dependent attenuation of all components of the CAP (P < 0.03). With 0.3-1.0 W power, the CAP recovered to > 95% of the control levels 7 minutes after lasing; recovery was incomplete after lasing at > 2.0 W. CONCLUSION: Isolated nerves were remarkably tolerant of lasing. The degree of nerve conduction block increased with laser power. The data indicate that lasing could diminish sensations, including pain, mediated by peripheral nerves in soft tissues.

Action Potentials↗
PubMed1978

Spinal nerve compression: a cause of claudication.

Thirteen patients were referred with claudication thought by the referring doctor to be vascular in origin. A careful history and physical examination followed by contrast radiculography showed their symptoms to be due to spinal nerve compression. The clinical picture is presented and the main pitfalls in diagnosis is considered. It was stressed that the taking of a careful history is the most important factor in arriving at a correct diagnosis.

Adult↗
PubMed2006

Spinal nerve sheath myxoma (neurothekeoma).

Nerve sheath myxoma (NSM) is a rare, benign tumor of predominantly cutaneous location. They usually arise from small cutaneous nerves in the head, neck, and extremities, but exceptionally they arise from spinal nerve roots. Only three cases of intraspinal NSM have been reported. Herein is describe two additional cases of spinal NSM. The patients were 64-year-old and 31-year-old men who presented with low back pain. Spine magnetic resonance imaging showed small intradural extramedullary masses at the L2-3 level. Both tumors had typical histological features of myxoid-type NSM. The tumors had a strong immunoreactivity for vimentin, S-100 protein, and neuron-specific enolase and focal expression of epithelial membrane antigen and phosphorylated neurofilament. Ultrastructural observation of tumor cells with perineurial, fibroblast-like, and Schwann-cell differentiation suggests an origin from nerve sheath precursor cells.

Adult↗
PubMed1990

Alphaherpesvirus saimiri infection in rabbits. 2. Morphometric studies of cutaneous spinal nerves.

To provide a better insight into the ultrastructural pathology of herpetic neuropathy, quantitative studies were made on cutaneous spinal nerves of normal rabbits and rabbits intradermally infected with alphaherpesvirus saimiri (alpha HVS) isolate KM 322. Marked reductions in the numbers and densities of myelinated and unmyelinated axons were found in the nerves of the rabbits killed 17 and 45 days after the infection. Abnormalities in the size distribution of unmyelinated axons were seen at 45 days post-inoculation where axonal sprouting caused a noticeable shift in the fiber population. Two years after virus inoculation reduction in unmyelinated axons and abnormalities in the fiber size distributions characterized by smaller diameters of both myelinated and unmyelinated axons were detected. In these nerves conspicuous fibrosis caused a significant increase in the endoneurial area. At this stage of the infection regenerative changes involving myelinated fibers were found. Since attempts to detect spontaneous reactivation of alpha HVS infection in rabbits have been unsuccessful, the finding of regeneration 2 years after exposure seems in agreement with the view that regenerated myelinated fibers never attain their original size. In the present study although both types of fibers were damaged, morphometric data suggest that unmyelinated axons were more severely affected. Whether this seemingly selective involvement was due to spreading of the virus between axons sharing the same Schwann cell subunit remains to be proved.

Animals↗
PubMed1995

Return of function after spinal cord implantation of avulsed spinal nerve roots.

Avulsion of nerve roots from the spinal cord is widely regarded as an untreatable injury. However, a series of experiments in animals has shown that, if continuity is restored between spinal cord and ventral roots, axons from spinal motor neurons can regrow into the peripheral nerves with recovery of motor function. These observations were applied in the treatment of a man with avulsion of the 6th cervical (C6) to 1st thoracic roots due to brachial plexus injury. Two ventral roots were implanted into the spinal cord through slits in the pia mater, C6 directly and C7 via sural nerve grafts. Voluntary activity in proximal arm muscles was detected electromyographically after nine months and clinically after one year. After three years the patient had voluntary activity (with some co-contraction) in the deltoid, biceps, and triceps muscles. To determine whether the improvement was due to spontaneous recovery from C5, the C5 root was blocked pharmacologically, and the results indicated that the repaired roots were contributing substantially to motor function. Repair of spinal nerve roots deserves further exploration in management of brachial plexus injury.

Adult↗
PubMed1998

Spinal nerve lesion-induced mechanoallodynia and adrenergic sprouting in sensory ganglia are attenuated in interleukin-6 knockout mice.

Tight ligation and transection of the L5 spinal nerve (SNL) gives rise to pain which is dependent upon activity in the sympathetic nervous system. It also results in novel adrenergic sympathetic innervation of the dorsal root ganglion (DRG) with the formation of pericellular axonal basket structures around some DRG neurons. Since the sympathetic sprouting and basket formation may represent an anatomical basis for pain-generating interactions between the sympathetic efferent neurons and sensory afferent neurons, it is of great interest to determine possible chemical mediators of this phenomenon. Previous findings have shown that IL-6 can contribute to sympathetically-independent pain, and can give rise to thermal hyperalgesia when injected intrathecally. We have now investigated a possible contributory role of the pleiotropic cytokine interleukin-6 (IL-6) in sympathetically-mediated pain: we gave IL-6 knockout mice and mice of the parent strain c57B6/129 a SNL, assessed their resulting pain behavior for 10 days post-surgery, and used tyrosine-hydroxylase immunohistochemistry to compare sympathetic sprouting in the DRG at the end of the testing period. We found that thermal allodynia (as assessed by measuring the latency to withdrawal from radiant heat) did not differ significantly between strains. On the other hand, in the IL-6 mice, mechanoallodynia (as assessed with von Frey filaments) was markedly delayed. Sympathetic invasion of the fiber tract and cell layer of the DRG, and the formation of pericellular axonal baskets were all significantly reduced in the IL-6 knockout mice compared to the control strain. These results imply a facilitatory role for IL-6 in pain and sympathetic sprouting induced by nerve injury, and add to the growing list of roles for IL-6 in neuropathological events.

Animals↗
PubMed1998

Responses of axotomized afferents to blockade of nitric oxide synthesis after spinal nerve lesion in the rat.

Lesioned afferents were tested for their responses to blockade of nitric oxide synthesis in the spinal nerve L5 lesion model for neuropathic pain in Wistar rats. Seven single fibers with spontaneous activity split from dorsal root L5 showed no response after non-selective blockade of nitric oxide synthesis with N(G)-nitro-L-arginine methyl ester whereas five were excited after 5-7 min. Three previously silent units were recruited. Blood flow in the dorsal root ganglion decreased. None of fifteen axotomized afferents tested responded to selective blockade of neuronal nitric oxide synthesis with 7-nitroindazole. It is concluded that neuronal nitric oxide is not involved in the generation of spontaneous activity in axotomized afferent neurons in this model. We suggest that the vasoconstriction induced by blockade of endothelial nitric oxide may be responsible for the excitatory responses.

Animals↗
PubMed2005

Spinal nerve root ganglionitis as a cause of disc herniation: case report.

The authors report on a patient in whom monoradicular pain was caused by ganglionitis of a spinal nerve. Neuroimaging and intraoperative findings identified what were thought to be tumorlike changes in the affected nerve root. The neuropathological examination, however, revealed typical signs of ganglionitis. This rare inflammation usually appears with viral infections, as part of paraneoplastic symptoms, or in the presence of Sjögren disease. Because all of these differential diagnoses were negative in the treated patient, chronic nerve root compression due to disc herniation was suspected as the causative factor for the spinal ganglionitis.

Diagnosis, Differential↗
PubMed1976

Melanotic tumours (Blue Naevi) of spinal nerve roots.

Four cases interpreted as intraspinal blue naevi are reported. The patients were adults females with an age range between 22 and 60 yr. In three there was a single tumour arising from the cervical posterior nerve roots and in the fourth there were multiple tumours arising from the posterior nerve roots of the spinal cord and occurring within the cerebello--pontine angle. The histological appearances of the tumours were similar in every way to those of dermal blue naevi. One was of the more common spindle-celled type and three of the cellular variant. The tumours contained melanin-pigment, and spindle cells with dendritic bipolar processes of the type described in dermal blue naevi. One was of the more common spindle-celled type and three of the cellular variant. The tumours contained melanin pigment, and spindle cells with dendritic bipolar processes of the type described in dermal blue naevi. Definite evidence of malignant tranformation was found in two cases and in a third, the appearances were suggestive for early malignant change. Therefore, unlike their dermal equivalents, intraspinal blue naevi appear to have a greater propensity for malignant transformation. In each case a careful clinical examination failed to reveal any evidence of a primary malignant melanoma. In the one case who died and on whom necropsy was performed, the failure to identify a primary cutaneous, mucosal or ocular melanoma substantiated our contention that these tumours were primary.

Adult↗
PubMed1993

Evolutionary diversification of cranial and spinal nerves and their targets in the gymnophione amphibians.

The ancestral gymnophione (caecilian) became elongate and limbless early in its history. Further structural reduction, including loss of components, followed by redirection and occasionally cooption of remaining structures, particularly muscles and nerves, has evolved. Function may remain that of the ancestral condition, or may change dramatically. Examples include the evolution of the tentacle, the jaw-closing apparatus, and the hypobranchial musculature, including their innervation. 'Regressive' evolution has provided opportunity for new structural-functional relationships and for increased variation.

Amphibians↗