An unusual case of thoracic outlet syndrome associated with long distance running. (1/67)

An amateur marathon runner presented with symptoms of thoracic outlet syndrome after long distance running. He complained of numbness on the C8 and T1 dermatome bilaterally. There were also symptoms of heaviness and discomfort of both upper limbs and shoulder girdles. These symptoms could be relieved temporarily by supporting both upper limbs on a rail or shrugging his shoulders. The symptoms and signs would subside spontaneously on resting. An exercise provocative test and instant relief manoeuvre, which are the main diagnostic tests for this unusual case of "dynamic" thoracic outlet syndrome, were introduced.  (+info)

Ventricular rate control during atrial fibrillation by cardiac parasympathetic nerve stimulation: a transvenous approach. (2/67)

OBJECTIVES: To identify intravascular sites for continuous, stable parasympathetic stimulation (PS) in order to control the ventricular rate during atrial fibrillation (AF). BACKGROUND: Ventricular rate control during AF in patients with congestive heart failure is a significant clinical problem because many drugs that slow the ventricular rate may depress ventricular function and cause hypotension. Parasympathetic stimulation can exert negative dromotropic effects without significantly affecting the ventricles. METHODS: In 22 dogs, PS was performed using rectangular stimuli (0.05 ms duration, 20 Hz) delivered through a catheter with an expandable electrode-basket at its end. The catheter was positioned either in the superior vena cava (SVC, n = 6), coronary sinus (CS, n = 10) or right pulmonary artery (RPA, n = 6). The basket was then expanded to obtain long-term catheter stability. Atrial fibrillation was induced and maintained by rapid atrial pacing. RESULTS: Nonfluoroscopic (SVC) and fluoroscopic (CS/RPA) identification of effective intravascular PS sites was achieved within 3 to 10 min. The ventricular rate slowing effect during AF started and ceased immediately after on-offset of PS, respectively, and could be maintained over 20 h. In the SVC, at least a 50% increase of ventricular rate (R-R) intervals occurred at 22 +/- 11 V (331 +/- 139 ms to 653 +/- 286 ms, p < 0.001), in the CS at 16 +/- 10 V (312 +/- 102 ms vs. 561 +/- 172 ms, p < 0.001) and in the RPA at 18 +/- 7 V (307 +/- 62 ms to 681 +/- 151 ms, p < 0.001). Parasympathetic stimulation did not change ventricular refractory periods. CONCLUSIONS: Intravascular PS results in a significant ventricular rate slowing during AF in dogs. This may be beneficial in patients with AF and rapid ventricular response since many drugs that decrease atrioventricular conduction have negative inotropic effects which could worsen concomitant congestive heart failure.  (+info)

Fast (3 Hz and 10 Hz) and slow (respiratory) rhythms in cervical sympathetic nerve and unit discharges of the cat. (3/67)

1. In seven decerebrate cats, recordings were taken from the preganglionic cervical sympathetic (CSy) nerves and from 74 individual CSy fibres. Correlation and spectral analyses showed that nerve and fibre discharges had several types of rhythm that were coherent (correlated) between population and unit activity: respiratory, '3 Hz' (2-6 Hz, usually cardiac related), and '10 Hz' (7-13 Hz). 2. Almost all units (73/74) had respiratory modulation of their discharge, either phasic (firing during only one phase) or tonic (firing during both the inspiratory (I) and expiratory (E) phases). The most common pattern consisted of tonic I-modulated firing. When the vagi were intact, lung afferent input during I greatly reduced CSy unit and nerve discharge, as evaluated by the no-inflation test. 3. The incidence of unit-nerve coherent fast rhythms (3 Hz or 10 Hz ranges) depended on unit discharge pattern: they were present in an appreciable fraction (30/58 or 52 %) of tonic units, but in only a small fraction (2/15 or 13 %) of phasic units. 4. When baroreceptor innervation (aortic depressor amd carotid sinus nerves) was intact, rhythms correlated to the cardiac cycle frequency were found in 20/34 (59 %) of units. The cardiac origin of these rhythms was confirmed by residual autospectral and partial coherence analysis and by their absence after baroreceptor denervation. 4. The 10 Hz coherent rhythm was found in 7/34 units when baroreceptor innervation was intact, where it co-existed with the cardiac-locked rhythm; after barodenervation it was found in 9/50 neurones. Where both rhythms were present, the 10 Hz component was sometimes synchronized in a 3:1 ratio to the 3 Hz (cardiac-related) frequency component. 5. The tonic and phasic CSy units seem to form distinct populations, as indicated by the differential responses to cardiac-related afferent inputs when baroreceptor innervation is intact. The high incidence of cardiac-related correlation found among tonic units suggests that they are involved in vasomotor regulation. The high incidence of respiratory modulation of discharge suggests that the CSy units may be involved in regulation of the nasal vasculature and consequent ventilation-related control of nasal airway resistance.  (+info)

Complications from regional anaesthesia for carotid endarterectomy. (4/67)

The complications of carotid endarterectomy (CEA) under cervical plexus blockade have yet to be fully evaluated. Two different cases are presented; both patients suffered sudden collapse following superficial and deep cervical plexus block in preparation for CEA. The causes, presenting signs and differential diagnoses are discussed. The safest cervical plexus anaesthetic block technique has not yet been established.  (+info)

Cranial and cervical nerve injuries after repeat carotid endarterectomy. (5/67)

BACKGROUND AND PURPOSE: The incidence of cranial and/or cervical nerve injuries after primary carotid endarterectomy (CEA) ranges from 3% to 48%; however, the clinical outcome of these injuries after repeat CEA has not been thoroughly analyzed in the English-language medical literature. This prospective study analyzes the incidence and outcome of cranial nerve injuries after repeat CEA. PATIENTS AND METHODS: This study includes 89 consecutive patients who had repeat CEAs. Preoperative and postoperative cranial nerve evaluations were performed, including clinical examinations (neurologic) and direct laryngoscopy. Patients with vagal or glossopharyngeal nerve injuries also underwent comprehensive speech evaluations, video stroboscopy, fluoroscopy, and methylene blue testing for aspiration. Patients with postoperative cranial nerve injuries were followed up for a long time to assess their recovery. RESULTS: Twenty-five cranial and/or cervical nerve injuries were identified in 19 patients (21%). They included 8 hypoglossal nerves (9%), 11 vagal nerves or branches (12%) (6 recurrent laryngeal nerves [7%], 3 superior laryngeal nerves [3%], and 2 complex vagal nerves [2%]), 3 marginal mandibular nerves (3%), 2 greater auricular nerves (2%), and 1 glossopharyngeal nerve (1%). Twenty-two (88%) of these injuries were transient with a complete healing time ranging from 2 weeks to 28 months (18 of 22 injuries healed within 12 months). The remaining three injuries (12%) were permanent (1 recurrent laryngeal nerve, 1 glossopharyngeal nerve, and 1 complex vagal nerve injury). The recurrent laryngeal nerve injury had a longer healing time than the other cranial nerve injuries. CONCLUSIONS: Repeat CEA is associated with a high incidence of cranial and/or cervical nerve injuries, most of which are transient. However, some of these have a long healing time, and a few can be permanent with significant disability.  (+info)

Evaluation of a cerebral oximeter as a monitor of cerebral ischemia during carotid endarterectomy. (6/67)

BACKGROUND: Stroke is an important contributor to perioperative morbidity and mortality associated with carotid endarterectomy (CEA). This investigation was designed to compare the performance of the INVOS-3100 cerebral oximeter to neurologic function, as a means of detecting cerebral ischemia induced by carotid cross-clamping, in patients undergoing carotid endarterectomy with cervical plexus block. METHODS: Ninety-nine patients undergoing 100 CEAs with regional anesthesia (deep or superficial cervical plexus block) were studied. Bilateral regional cerebrovascular oxygen saturation (rSO2) was monitored using the INVOS-3100 cerebral oximeter. Patients were retrospectively assigned to one of two groups: those in whom a change in mental status or contralateral motor deficit was noted after internal carotid clamping (neurologic symptoms; n = 10) and those who did not show any neurologic change (no neurologic symptoms; n = 90). Data from 94 operations (neurologic symptoms = 10 and no neurologic symptoms = 84) were adequate for statistical analyses for group comparisons. A relative decrease in ipsilateral rSO2 after carotid occlusion (calculated as a percentage of preocclusion value) during all operations (n = 100) was also calculated to determine the critical level of rSO2 decrease associated with a change in neurologic function. RESULTS: The mean (+/- SD) decrease in rSO2 after carotid occlusion in the neurologic symptoms group (from 63.2 +/- 8.4% to 51.0 +/- 11.6%) was significantly greater (P = 0.0002) than in the no neurologic symptoms group (from 65.8 +/- 8.5% to 61.0 +/- 9.3%). Logistic regression analysis used to determine if a change in rSO2, calculated as a percentage of preclamp value, could be used to predict change in neurologic function was highly significant (likelihood ratio chi-square = 13.7; P = 0.0002). A 20% decrease in rSO2 reading from the preclamp baseline, as a predictor of neurologic compromise, resulted in a sensitivity of 80% and specificity of 82.2%. The false-positive rate using this cutoff point was 66.7%, and the false-negative rate was 2.6%, providing a positive predictive value of 33.3% and a negative predictive value of 97.4%. CONCLUSION: Monitoring rSO2 with INVOS-3100 to detect cerebral ischemia during CEA has a high negative predictive value, but the positive predictive value is low.  (+info)

Division of C8 nerve root for treatment of spastic cerebral palsy in the upper limbs: a preliminary report. (7/67)

OBJECTIVE: To investigate the effect of C8 nerve root division on the treatment of spastic cerebral palsy in the upper limbs. METHODS: Two patients were treated with division of the C8 never root. Supraclavicular incision was made to expose the C5-T1 nerve roots. The intraoperative electromyographic recording technique was used to monitor the responses from the flexor digitorum and flexor carpi ulnaris muscle groups simultaneously. The C5-T1 nerve roots were stimulated and the evoked muscle amplitude potentials (EMAP) were recorded from the muscle groups. The EMAP of the muscle groups obtained during electrical stimulation of the C8 nerve root was the largest, which was used as the basis for C8 nerve root division. RESULTS: Division of the C8 nerve root slightly affected the function of the upper limb, and reduced the muscle tone of the flexor wrist and digitorum. CONCLUSION: Division of the C8 nerve root can reduce the muscle tone of the flexor wrist and digitorum in a short time. The long-term effects need to be followed up further.  (+info)

Abnormalities in Schwann cell sheaths in spinal nerve roots of dystrophic mice. (8/67)

Dorsal and ventral spinal roots at cervical, thoracic, lumbar and sacral levels in dystrophic, dy/dy, mice of both 129/ReJ and C57Bl/6J phenotypes showed a complete lack of Schwann cell sheaths of any sort around the majority of their nerve fibres. This condition, termed amyelination, is more extensive (up to 1-5 cm in length) in the longer lumbar and sacral roots than in the shorter roots or in the proximal regions of the sciatic nerve which are also affected to some extent. Amyelination does not appear to be a consequence of myelin or Schwann cell degeneration, as debris is uncommon. Heterozygous carriers are not affected in any obvious way. Myelinated fibres, with Schwann cells of peripheral origin, occur immediately adjacent to the spinal cord in both dorsal and ventral roots, while in dorsal roots unmyelinated fibres also occur, as in normal animals. Amyelinated fibres begin to appear a few internodal lengths away from the cord and are present until near, or within, the dorsal root ganglion, where they become myelinated again. The portion of an axon which has no myelin begins at a normal appearing paranodal region (termed a half node of Ranvier) at the end of a myelin internode. Resumption of myelination likewise begins at a half node. A few myelinated axons may be seen in any given cross section of a root, but as a rule a given myelinated fibre does not remain myelinated throughout the whole length of the root. It is suggested that the nerve lesions develop where the nerves are lengthening rapidly as the animal grows and changes its shape. How these nerve changes release to those in muscle is conjectural.  (+info)

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