Anatomical variations of the phrenic nerve and its clinical implication for supraclavicular block. (73/402)

This paper reports a case of simultaneous diaphragmatic and brachial plexus stimulation followed by a successful nerve block using the supraclavicular approach. An explanation for the qualitative differences in phrenic nerve block between interscalene and supraclavicular block is postulated, based on known anatomical variations.  (+info)

Clinical analysis of the trigger thumb of childhood. (74/402)

Trigger thumb of childhood, termed congenital trigger thumb, is a pathology of the flexor pollicis longus tendon with an unknown etiology. In this study, treatment outcomes of 47 trigger thumbs of 36 children were evaluated. There were 18 males and 18 females with a mean age of 34 months (9 months-13 years). Average age of recognition of pathology by the family was 20.5 months (0-8 years). In seven of 11 bilateral cases pathology was recognized simultaneously while in the other four, diagnosis was made at different times. We used conservative treatment for all patients under three years of age, which was unsuccessful. Thus, surgical relase was performed in all cases. In the mean follow-up of seven years (range 5-15), contracture and palpable nodules disappeared. In conclusion, we believe trigger thumb in childhood should be treated surgically and that the term "congenital trigger thumb" should be changed to "developmental trigger thumb".  (+info)

Enhancing encoding of a motor memory in the primary motor cortex by cortical stimulation. (75/402)

Motor training results in encoding of motor memories, a form of use-dependent plasticity. Here we tested the hypothesis that transcranial magnetic stimulation (TMS) synchronously applied to a motor cortex engaged in a motor training task could enhance this plastic process. Healthy volunteers were studied in four sessions: training consisting of performance of directionally specific voluntary thumb movements (Train alone), training with TMS delivered during the execution of the training movement in a strictly temporal relationship to the motor cortex contralateral (Train+TMS synchronous(contra)) and ipsilateral (Train+TMS synchronous(ipsi)) to the training hand, and training with TMS delivered asynchronous to the training movement to the motor cortex contralateral to the training hand (Train+TMS asynchronous(contra)). Train alone, Train+TMS synchronous(contra), and Train+TMS asynchronous(contra) but not Train+TMS synchronous(ipsi) elicited a clear motor memory. The longevity of the encoded memory was significantly enhanced by Train+TMS synchronous(contra) when compared with Train alone and Train+TMS asynchronous(contra). Therefore use-dependent encoding of a motor memory can be enhanced by synchronous Hebbian stimulation of the motor cortex that drives the training task and reduced by stimulation of the homologous ipsilateral motor cortex, a result relevant for studies of cognitive and physical rehabilitation.  (+info)

Learning modifies subsequent induction of long-term potentiation-like and long-term depression-like plasticity in human motor cortex. (76/402)

Learning may alter rapidly the output organization of adult motor cortex. It is a long-held hypothesis that modification of synaptic strength along cortical horizontal connections through long-term potentiation (LTP) and long-term depression (LTD) forms one important mechanism for learning-induced cortical plasticity. Strong evidence in favor of this hypothesis was provided for rat primary motor cortex (M1) by showing that motor learning reduced subsequent LTP but increased LTD. Whether a similar relationship exists in humans is unknown. Here, we induced LTP-like and LTD-like plasticity in the intact human M1 by an established paired associative stimulation (PAS) protocol. PAS consisted of 200 pairs of electrical stimulation of the right median nerve, followed by focal transcranial magnetic stimulation of the hand area of the left M1 at an interval equaling the individual N20 latency of the median nerve somatosensory-evoked cortical potential (PAS(N20)) or N20-5 msec (PAS(N20-5)). PAS(N20) induced reproducibly a LTP-like long-lasting (>30 min) increase in motor-evoked potentials from the left M1 to a thumb abductor muscle of the right hand, whereas PAS(N20-5) induced a LTD-like decrease. Repeated fastest possible thumb abduction movements resulted in learning, defined by an increase in maximum peak acceleration of the practiced movements, and prevented subsequent PAS(N20)-induced LTP-like plasticity but enhanced subsequent PAS(N20-5)-induced LTD-like plasticity. The same number of repeated slow thumb abduction movements did not result in learning and had no effects on PAS-induced plasticity. Findings support the view that learning in human M1 occurs through LTP-like mechanisms.  (+info)

Microvascularization of the human digit as studied by corrosion casting. (77/402)

The aim of this study was to describe microcirculation in the human digit, focusing on the vascular patterns of its cutaneous and subcutaneous areas. We injected a functional supranumerary human thumb (Wassel type IV) with a low-viscosity acrylic resin through its digital artery. The tissues around the vessels were then digested in hot alkali and the resulting casts treated for scanning electron microscopy. We concentrated on six different areas: the palmar and dorsal side of the skin, the eponychium, the perionychium, the nail bed and the nail root. On the palmar side, many vascular villi were evident: these capillaries followed the arrangement of the fingerprint lines, whereas on the dorsal side they were scattered irregularly inside the dermal papillae. In the hypodermal layer of the palmar area, vascular supports of sweat glands and many arteriovenous anastomoses were visible, along with glomerular-shaped vessels involved in thermic regulation and tactile function. In the eponychium and perionychium, the vascular villi followed the direction of nail growth. In the face of the eponychium in contact with the nail, a wide-mesh net of capillaries was evident. In the nail bed, the vessels were arranged in many longitudinal trabeculae parallel to the major axis of the digit. In the root of the nail, we found many columnar vessels characterized by multiple angiogenic buttons on their surface.  (+info)

Individualized risks of first adverse events in patients with Fanconi anemia. (78/402)

Fanconi anemia (FA) is an autosomal recessive condition associated with bone marrow failure (BMF) leading to death or hematopoietic stem cell transplantation, acute myeloid leukemia (AML), and solid tumors (STs). It is unclear which patients are most likely to develop each outcome. From a cohort of 144 North American patients with FA, we calculated individualized risks of each outcome, given the presence or absence of readily diagnosed congenital abnormalities that occur frequently in FA. Abnormal radii and a 5-item congenital abnormality score were significant risk factors for BMF. The cumulative incidence of BMF by age 10 years varied from 18% in the lowest BMF risk group to 83% in the highest. Because of competing risks, patients in the lowest BMF risk group were most likely to live long enough to develop AML or ST, and, conversely, patients in the highest BMF risk group were least likely to live long enough to develop AML or ST. By age 40, the cumulative incidence of ST ranged from 0.6% to 29% in the highest and lowest BMF risk groups, respectively. Abnormal radii are the strongest predictor of early BMF in FA; a congenital abnormality score separates patients with normal radii into distinct prognostic groups.  (+info)

Evaluation of an instrumented glove for hand-movement acquisition. (79/402)

Quantitative assessment of digit range of motion (ROM) is often needed for monitoring effectiveness of rehabilitative treatments and assessing patients' functional impairment. The objective of this research was to investigate the feasibility of using the Humanware Humanglove, a 20-position sensors glove, to measure fingers' ROM, with particular regard to measurement repeatability. With this aim, we performed a series of tests on six normal subjects. Data analysis was based on statistical parameters and on the intraclass correlation coefficient (ICC). Sources of errors that could affect measurement repeatability were also analyzed. The results demonstrate that, in principle, the glove could be used as goniometric device. The main advantage yielded by its use is reduction in the time needed to perform the whole measurement process, while maintaining process repeatability comparable to that achieved by traditional means of assessment. It also allows for dynamic and simultaneous recording of hand-joint movements. Future work will investigate accuracy of measurements.  (+info)

Disability induced by hand osteoarthritis: are patients with more symptoms at digits 2-5 interphalangeal joints different from those with more symptoms at the base of the thumb? (80/402)

BACKGROUND: The contribution of osteoarthritis (OA) at the base of the thumb (BT) and digits 2-5 interphalangeal joints (IP) to disability in the hand has never been assessed. OBJECTIVES: To evaluate and compare disability in patients with clinical hand OA and more severe symptoms at BT or IP. DESIGN: Observational, prospective, correlational. SETTING: Rheumatology and rehabilitation departments in two tertiary care teaching hospitals. PARTICIPANTS: One hundred and sixteen patients (107 women, mean age 62+/-7 years) fulfilling the American College of Rheumatology criteria for OA in the hand, with more symptomatic BT (67 patients) or IP (49 patients). MAIN OUTCOME MEASURE: Disability assessment with Cochin hand functional scale (CHFS) was the primary outcome. Assessment of impairment by the visual analog scale of pain (VAS pain), Ritchie articular index (RAI), modified Kapandji index (mKI), Kallman radiological classification and handicap assessment with visual analog scale (VASHd) was the secondary outcome. Group comparisons were assessed by use of Student's t-test for quantitative variables and Chi-square test for categorical variables. Results of the CHFS analysis were assessed by factorial analysis followed by Varimax rotation. Correlation between scores of disability, impairment, and handicap measures were calculated with use of Spearman rank correlation coefficient. RESULTS: Demographic data, disease duration, and level of global pain were similar between the BT and IP groups. The BT and IP groups did not differ significantly according to disability and handicap level (P=0.42 and P=0.94 for CHFS total score and VASHd, respectively). Factor analysis of the CHFS revealed similar results for the two groups of patients, especially for the first extracted factor. Disability scores correlated best with global hand pain (r=0.65) in the BT group and with RAI scores (r=0.71) in the IP group. CONCLUSIONS: Disability and perceived handicap levels are comparable in clinical hand OA patients with more symptomatic BT or IP. These two groups should not be considered different during trials assessing treatments for hand OA when the primary outcome measure assesses disability.  (+info)