Incidence of clinically symptomatic pneumothorax in ultrasound-guided infraclavicular and supraclavicular brachial plexus block.

The use of periclavicular brachial plexus block as regional anaesthesia for surgical procedures on the upper extremity is common. However, the proximity of the pleura results in a risk of pneumothorax. Without ultrasound monitoring, the pneumothorax risk has been reported to be as high as 6.1%. We conducted a prospective, observational study to examine the risk of pneumothorax in 6366 ultrasound-guided periclavicular plexus blocks. All patients with a clinically manifest and radiologically confirmed pneumothorax were analysed. Clinically symptomatic pneumothorax occurred in four patients (0.06%; 95% CI 0.001-0.124), in three of them after a two-day latency period. Ultrasound guidance does therefore appear to reduce the risk of pneumothorax. Although all of the anaesthesiologists involved in the complications had previously performed fewer than 20 blocks, we are not able to confirm that a block experience ≤ 20 is a significant risk factor. Faulty image-setting, inability to obtain a view of the needle tip and inadequate supervision are likely to be important risk factors.

Source and origin of nerve fibres immunoreactive for substance P and calcitonin gene-related peptide in the normal and chronically denervated superior cervical sympathetic ganglion of the rat.

Immunohistochemical studies of sympathetic ganglia have indicated that the normal rat superior cervical ganglion contains both SP-IR and CGRP-IR fibres, and CGRP- and SP-immunoreactivity coexist in some fibres. In rat sympathetic ganglia decentralization by preganglionic denervation leads to intraganglionic increase of peptidergic fibres immunoreactive (IR) for substance P (SP) and calcitonin gene-related peptide. We explored the sources of SP- and CGRP-IR fibres in normal and in chronically decentralized rat SCGs. The distribution of immunoreactivities for CGRP and SP was determined in SCGs of normal rats and of rats following preganglionic denervation followed by sensory denervation. Ganglia were studied after short-term (2-5 days) sensory denervation, and long-term (7-16 months) sympathetic denervation followed by short-term (2 days) sensory denervation. To explore for the production of SP and CGRP by intrinsic neurones within the ganglion, normal and chronically decentralized SCGs were examined following pretreatment by local in vivo application of colchicine. Normal and chronically decentralized ganglia were also injected with fluorescent tracer Fluorogold for retrograde tracing of extrinsic fibres back to their neurones of origin. The observations suggest that in normal SCG in the rat the SP-IR and CGRP-IR nerve fibres are derived via direct links from vagus and glossopharyngeal nerves and the cervical plexus, or from nerve fibres running along the cervical sympathetic trunk, and the external carotid and the internal carotid nerves. Sensory nerve inputs to the rat SCG following decentralization may contribute to the low levels of ganglionic activation observable in the autonomic failure of multiple system atrophy in man.

Remodeling of synaptic connections in the deafferented vestibular nuclear complex.

To determine if synaptic remodeling in the vestibular nuclear complex (VNC) may be involved in vestibular compensation, expressions of growth-associated protein-43 (GAP-43) and synaptosome-associated protein of 25 kDa (SNAP-25) were examined by immunoblotting and immunocytochemistry after unilateral vestibular ganglionectomy (UVG) in rats. GAP-43 expression increased bilaterally in the VNC after UVG, but more rapidly on the lesioned side, and remained high through 60 days. It was mainly associated with boutons at all survival times but was also present in some axonal processes and, at 7 days after UVG, in some somata. SNAP-25 expression also increased bilaterally, more rapidly on the lesioned side, but decreased bilaterally after peaking at 14 days. Its distribution in the VNC resembled that of GAP-43 but was more completely localized to boutons. Comparisons were made with auditory centers of the same rats, since the lesion also deafferented that system. Our results combined with those of previous studies suggest that degeneration of the vestibular nerve fibers is required for increased expression of GAP-43 in the VNC. The results suggest that axonal sprouting and synaptogenesis are involved in synaptic remodeling bilaterally in the rat VNC after UVG.

Symptomatic epineural ganglion cyst of the ulnar nerve in the cubital tunnel: a case report and brief review of the literature.

An unusual case of pain and weakness in the hand and forearm due to a ganglion cyst of the ulnar nerve at the elbow is presented. The patient was managed initially as a case of cervical disc disease and cervical spondylosis and later as a case of carpal tunnel syndrome at an another institution. Cervical radiography and cervical magnetic resonance imaging scans were inconclusive. Neurosurgical referral revealed tenderness at the right cubital tunnel, weakness of the right hand and forearm muscles, and sensory deficit along the medial border of the forearm and the hand. The diagnosis of ulnar nerve compression at the elbow was made. Nerve conduction studies of the ulnar nerve at the elbow confirmed the diagnosis. A ganglion cyst of the ulnar nerve was excised microsurgically with a complete postoperative sensory motor recovery.

[A structural organization of the sensory projections on a reticular formation of the brain stem]. / Strukturnaia organizatsiia sensornykh proektsii na retikuliuarnuiu formatsiiu stvola mozga.

The animal experiments were performed by the cutting the sensory afferent tracts which had the projections on the reticular formation (RF) of brain stem, namely--visual, acoustic and taste tracts. Brain was investigated by methods of Marki, Nauta, Fink-Haimer. A quantitative evaluation of the voluminous fractions of neurons and gla was carried out by using "Classimat" device. Capillary density was also counted. A morphologic substrate for the conduction of the specific influences was found in form of both afferent fibers entering in brain stem and the cell groups associated with them. Between the specific brain stem and reticular structures of medulla oblongata, brain stem and midbrain (n.cuneiformis, n. tegmenti pedunculo-ponticus, n.centralis oralis and caudalis pontis, n. papillioformis, n. parabrachialis medialis and n. parvocellularis) intermediate zones were determined which were localized on the junction between sensory and reticular nuclei and had specific afferentation. Intermediate zones were also found in RF between the nuclei in both oral-caudal and mediolateral directions. An idea was formulated about the differencies in a structural organization of RF in medulla oblongata, brain stem and midrain, that were conditioned by a multicentral localization of RF functions.

Intraneural mucoid cysts of the upper limb.

Intraneural mucoid cysts are uncommon. They usually affect middle-aged men, presenting with pain and symptoms of nerve compression. We report on our series of six patients, three of whom had cysts involving the digital nerves. We compare our series with others and discuss controversies concerning the existence, aetiology, treatment and outcome of these cysts. We believe MR scans can aid in the preoperative diagnosis and follow-up of these patients and that, if possible, careful cyst excision using an operative microscope is the treatment of choice.