Primary hemorrhagic intramedullary melanoma. Case report with emphasis on the difficult preoperative diagnosis.

Primary melanoma of the central nervous system (CNS) is rare and primary spinal melanoma (PSM) is even more unusual. Preoperative diagnosis of melanocytic lesion as a PSM is difficult, because of the heterogeneous magnetic resonance (MR) signal intensity, due to hemorrhagic foci and melanin deposits. We describe the case of a 68 year-old male with a MR showing at Th8-Th9 level a well-defined intramedullary lesion; for the characteristics of hemorrhagic signal on MR and its association with a presumptive brain cavernoma, a preoperative diagnosis of intramedullary cavernous angioma was suspected. Pathological examination revealed a melanoma, and for the absence of other localizations outside the spinal cord, a diagnosis of primary spinal melanoma was established. The growth of PSM is slower and survival is longer than in the most common spinal metastasis from skin melanoma. Patients who undergo surgical excision, alone or associated with additional treatments, often show a long survival. We report this case to underline the importance and difficulties concerning the preoperative diagnosis of a hemorrhagic intramedullary lesion.

End-to-side nerve neurorrhaphy: critical appraisal of experimental and clinical data.

End-to-side neurorrhaphy (ESN) or terminolateral neurorraphy consists of connecting the distal stump of a transected nerve, named the recipient nerve, to the side of an intact adjacent nerve, named the donor nerve, "in which only an epineurial window is performed". This procedure was reintroduced in 1994 by Viterbo, who presented a report on an experimental study in rats. Several experimental and clinical studies followed this report with various and sometimes conflicting results. In this paper we present a review of the pertinent literature. Our personal experience using a sort of end-to-side nerve anastomosis, in which the donor nerve is partially transected, is also presented and compared with ESN as defined above. When the proximal nerve stump of a transected nerve is not available, ESN, which is claimed to permit anatomic and functional preservation of the donor nerve, seems an attractive technique, though yet not proven to be effective. Deliberate axotomy of the donor nerve yields results that are proportional to the entity of axotomy, but such technique, though resembling ESN, is an end-to-end neurorrhaphy. Neither experimental or clinical evidence support liberalizing the clinical use of ESN, a procedure with only an epineurial window in the donor nerve and without deliberate axotomy. Much more experimental investigation needs to be done to explain the ability of normal, intact nerves to sprout laterally. Such procedure appears justified only in an investigational setting.

A new animal model for monitoring the early cerebral vasospasm after subarachnoid haemorrhage.

AIM: Spasm of cerebral arteries is a complication associated with subarachnoid haemorrhage. The aim of the present work is to find an experimental model of reliable, simple and in vivo monitoring of ''early'' basilar artery spasm after subarachnoid haemorrhage (SAH). Early spasm occurs within minutes of the SAH, its duration is approximately 1 hour. The need of different morphological and haemodynamic methods to evaluate experimental early spasm is reported. METHODS: To overcome intracranial surgical manipulations and biological of contrast and fixation media we designed a model that allows in vivo functional monitoring of basilar blood flow far away from the spasm without direct surgical and chemical interferences. Seventeen adult Burgundy rabbits were studied. RESULTS: Under homeostatic monitoring ''on-line'' carotid blood flow (carotid BF) .changes produced by SAH in cisterna magna of 12 (plus 5 sham treated) animals were studied from the common carotid artery after external carotid artery occlusion before, during SAH up to the end of the experiments. All the animals underwent digital subtraction cerebral panangiography (CPA) after SAH obtaining a significant increase of carotid BF only when basilar vasospasm was shown by CPA. CONCLUSIONS: Carotid BF increase during basilar vasospasm was defined ''functional. monitoring'' of early spasm.

Deafferentation-induced apoptosis of neurons in thalamic somatosensory nuclei of the newborn rat: critical period and rescue from cell death by peripherally applied neurotrophins.

This study shows that unilateral transection of the infraorbital nerve (ION) in newborn (P0) rats induces apoptosis in the contralateral ventrobasal thalamic (VB) complex, as evidenced by terminal transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL) and electron miscroscopy. Double-labelling experiments using retrograde transport of labelled microspheres injected into the barrel cortex, followed by TUNEL staining, show that TUNEL-positive cells are thalamocortical neurons. The number of TUNEL-positive cells had begun to increase by 24 h postlesion, increased further 48 h after nerve section, and decreased to control levels after 120 h. Lesion-induced apoptosis in the VB complex is less pronounced if ION section is performed at P4, and disappears if the lesion is performed at P7. This time course closely matches the critical period of lesion-induced plasticity in the barrel cortex. Nerve growth factor (NGF) or brain-derived neurotrophic factor (BDNF), applied on the ION stump alone or in combination, are able to partially rescue thalamic neurons from apoptosis. Total cell counts in the VB complex of P7 animals that underwent ION section at P0 confirm the rescuing effect of BDNF and NGF. Blockade of axonal transport in the ION mimics the effect of ION section. These data suggest that survival-promoting signals from the periphery, maybe neurotrophins, are required for the survival of higher-order neurons in the somatosensory system during the period of fine-tuning of neuronal connections. We also propose that anterograde transneuronal degeneration in the neonatal rat trigeminal system may represent a new animal model for studying the pathways of programmed cell death in vivo.