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A study was undertaken in which the handgrip strength in three arm positions above the shoulder was measured to compare handgrip strength when arm support is used and when it is not used. Grip forces were generated in pairs of flexion angles, corresponding to shoulder and elbow at 90°-90°, 135°-45° and 160°-20°. Thirty-two participants completed the present study; 23 men and nine women with a median age of 23.1 (SD ±3.6) years. A manual handgrip dynamometer (0-90 kg) and an adjustable angle arm support (AAAS) were used during the data collection. Two-way analysis of variance (ANOVA) for repeated measurements indicates a significant effect of the AAAS factor on the handgrip strength, as well as on the AAAS × angle interaction. However, there is no significant effect of the angle factor on the AAAS × angle interaction.

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We describe the patterns of motor branches to the elbow flexors in 106 fresh-frozen cadaveric upper extremities from 53 donors of the Latin American mestizo race. We identified a 20% incidence of an accessory biceps head. The innervation patterns to this accessory head were specifically described and added to the Yang classification as Type IV for the biceps and Type III for the brachialis. The patterns arising from the musculocutaneous nerve to the biceps brachii were of Type I in 69%, Type II in 9%, Type III in 7% and Type IV in 11%, and to the brachialis of Type I in 77%, Type II in 11% and Type III in 9%. In 4%, the branches did not originate from the musculocutaneous nerve. We hypothesize that the branch to the accessory biceps head might be considered as a donor for nerve transfer in selected brachial plexus injuries.

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The shear elastic modulus is one of the most important parameters to characterize the mechanical behavior of soft tissues. In biomechanics, ultrasound elastography is the gold standard for measuring and mapping it locally in skeletal muscle in vivo. However, their applications are limited to the laboratory or clinic. Thus, low-frequency elastography methods have recently emerged as a novel alternative to ultrasound elastography. Avoiding the use of high frequencies, these methods allow obtaining a mean value of bulk shear elasticity. However, they are frequently susceptible to diffraction, guided waves, and near field effects, which introduces biases in the estimates. The goal of this work is to test the performance of the non-ultrasound surface wave elastography (NU-SWE), which is portable and is based on new algorithms designed to correct the incidence of such effects. Thus, we show its first application to muscle biomechanics. We performed two experiments to assess the relationships of muscle shear elasticity versus joint torque (experiment 1) and the electromyographic activity level (experiment 2). Our results were comparable regarding previous works using the reference ultrasonic methods. Thus, the NU-SWE showed its potentiality to get wide the biomechanical applications of elastography in many areas of health and sports sciences.

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BACKGROUND: Traumatic brachial plexus injuries cause long-term maiming of patients. The major target function to restore in complex brachial plexus injury is elbow flexion. OBJECTIVE: To retrospectively analyze the correlation between the length of the nerve graft and the strength of target muscle recovery in extraplexual and intraplexual nerve transfers. METHODS: A total of 51 patients with complete or near-complete brachial plexus injuries were treated with a combination of nerve reconstruction strategies. The phrenic nerve (PN) was used as axon donor in 40 patients and the spinal accessory nerve was used in 11 patients. The recipient nerves were the anterior division of the upper trunk (AD), the musculocutaneous nerve (MC), or the biceps branches of the MC (BBs). An index comparing the strength of elbow flexion between the affected and the healthy arms was correlated with the choice of target nerve recipient and the length of nerve grafts, among other parameters. The mean follow-up was 4 yr. RESULTS: Neither the choice of MC or BB as a recipient nor the length of the nerve graft showed a strong correlation with the strength of elbow flexion. The choice of very proximal recipient nerve (AD) led to axonal misrouting in 25% of the patients in whom no graft was employed. CONCLUSION: The length of the nerve graft is not a negative factor for obtaining good muscle recovery for elbow flexion when using PN or spinal accessory nerve as axon donors in traumatic brachial plexus injuries.

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INTRODUCTION: The traumatic lesions of the brachial plexus in adults are devastating injuries causing continuous severe functional impairment for both work and daily living activities. The restoration of elbow flexion is one of the most important movements for patient recovery to previous activities. Free gracilis muscle transfer has good outcomes for cases with late presentation or as a rescue surgery to regain elbow flexion, however, bad results are present in all cohorts with insufficient recovery of muscle strength for elbow flexion. A number of hypotheses can be postulate to explain the fair results observed in some cases of free gracilis muscle transfer for elbow flexion. Most studies in the current literature compare the choice of the donor nerve used in neurotization and nerve grafts. The aim of this study is to evaluate if technical components of microvascular anastomosis could influence the functional outcome of free functional muscle transfer for elbow flexion in adult patients with traumatic brachial plexus injury. MATERIAL AND METHODS: Included all adult patients with traumatic brachial plexus injury submitted to free functional gracilis muscle transfer for elbow flexion. The complications and functional results according to British Medical Research Council (BMRC) score were recorded. RESULTS: We assessed 26 patients with mean age of 32.8 years. The most common donor nerve for gracilis muscle was the accessory nerve in 18 patients. Eighteen patients presented with good result (M3/M4). The mean ischemia time was higher for patients with bad results (132 minutes) comparing with patients with good results (122 minutes). Patients with only one venous anastomosis had 41% of poor functional outcome compared with 22% of cases with two venous anastomoses. No statistically significant difference in the ischemia time of the cases with good or poor functional outcome was observed (p=0.657), as for the number of venous anastomoses (p=0.418). CONCLUSION: Our study observes that patients with only one venous anastomoses for drainage of free gracilis and those with longer intraoperative ischemia time had higher incidence of poor functional outcome of free gracilis muscle transfer for elbow flexion, but not statistically significant. LEVEL OF PROOF: II; prospective cross-sectional study.

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BACKGROUND: The phrenic nerve has been extensively reported to be a very powerful source of transferable axons in brachial plexus injuries. The most used technique used is supraclavicular sectioning of this nerve. More recently, video-assisted thoracoscopic techniques have been reported as a good alternative, since harvesting a longer phrenic nerve avoids the need of an interposed graft. OBJECTIVE: To compare grafting vs phrenic nerve transfer via thoracoscopy with respect to mean elbow strength at final follow-up. METHODS: A retrospective analysis was conducted among patients who underwent phrenic nerve transfer for elbow flexion at 2 centers from 2008 to 2017. All data analysis was performed in order to determine statistical significance among the analyzed variables. RESULTS: A total of 32 patients underwent supraclavicular phrenic nerve transfer, while 28 underwent phrenic nerve transfer via video-assisted thoracoscopy. Demographic characteristics were similar in both groups. A statistically significant difference in elbow flexion strength recovery was observed, favoring the supraclavicular phrenic nerve section group against the intrathoracic group (P = .036). A moderate though nonsignificant difference was observed favoring the same group in mean elbow flexion strength. Also, statistical differences included patient age (P = .01) and earlier time from trauma to surgery (P = .069). CONCLUSION: Comparing supraclavicular sectioning of the nerve vs video-assisted, intrathoracic nerve sectioning to restore elbow flexion showed that the former yielded statistically better results than the latter, in terms of the percentage of patients who achieve at least level 3 MRC strength at final follow-up. Furthermore, larger scale prospective studies assessing the long-term effects of phrenic nerve transfers remain necessary.

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Objective To present the functional outcomes of distal nerve transfer techniques for restoration of elbow flexion after upper brachial plexus injury. Method The files of 78 adult patients with C5, C6, C7 lesions were reviewed. The attempt to restore elbow flexion was made by intraplexus distal nerve transfers using a fascicle of the ulnar nerve (group A, n » 43), or a fascicle of themedian nerve (group B, n » 16) or a combination of both (group C, n » 19). The result of the treatment was defined based on the British Medical Research Council grading system: muscle strength < M3 was considered a poor result. Results The global incidence of good/excellent results with these nerve transfers was 80.7%, and for different surgical techniques (groups A, B, C), it was 86%, 56.2% and 100% respectively. Patients submitted to ulnar nerve transfer or double transfer (ulnar þ median fascicles transfer) had a better outcome than those submitted to median nerve transfer alone (p < 0.05). There was no significant difference between the outcome of ulnar transfer and double transfer. Conclusion In cases of traumatic injury of the upper brachial plexus, good and excelent results in the restoration of elbow flexion can be obtained using distal nerve transfers.

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Even though one of the surgical techniques most frequently used to correct external rotation deformity of the shoulder in brachial plexus patients is a humeral derotational osteotomy, few intraoperative parameters has yet been identified to determine the appropriate degree of rotation. We present in this technical note our initial experience using the main elbow flexion skin crease to quantify the correct rotation of the humerus in four young, male patients with upper-type brachial plexus injuries. All patients had a functional elbow and a stable shoulder, but also an external rotation deficit. Via a deltopectoral approach, we used the main elbow flexion crease as an intraoperative surgical parameter to determine the degree of external rotation of the humerus required to achieve a better positioning of the hand in space. After surgery, increased elbow flexion range and enhanced hand-to-face movement was observed, while internal rotation was preserved for performing midline activities. Moreover, all patients exhibited increased active elbow flexion and osteotomy consolidation, with mean elbow flexion increasing from 66.3° to 97.5° pre to postoperatively, and a mean 56.3° of internal rotation correction ultimately achieved. We propose that the main elbow flexion crease is a useful intraoperative parameter to determine the degree of intraoperative external rotation necessary to restore the plane of hand-face movements in upper-type palsies. LEVEL OF EVIDENCE: IV; case series.

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Resistance training (RT) offers benefits to both men and women. However, the studies about the differences between men and women in response to an RT program are not conclusive and few data are available about upper body strength response. The aim of this study was to compare elbow flexor strength gains in men and women after 10 weeks of RT. Forty-four college-aged men (22.63 ± 2.34 years) and forty-seven college-aged women (21.62 ± 2.96 years) participated in the study. The RT program was performed two days a week for 10 weeks. Before and after the training period, peak torque (PT) of the elbow flexors was measured with an isokinetic dynamometer. PT values were higher in men in comparison to women in pre- and post-tests (p < 0.01). Both males and females significantly increased elbow flexor strength (p < 0.05); however, strength changes did not differ between genders after 10 weeks of RT program (11.61 and 11.76% for men and women, respectively; p > 0.05). Effect sizes were 0.57 and 0.56 for men and women, respectively. In conclusion, the present study suggests that men and women have a similar upper body strength response to RT.

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BACKGROUND: A wide range of results have appeared in the literature for intercostal nerve transfers in brachial plexus patients. Oriental countries generally have a lower body mass index (BMI) than their occidental counterparts. We analyzed published series of intercostal nerve transfers for elbow reinnervation to determine if a difference in outcomes exists between Eastern and Western series that could be inversely related to BMI. METHODS: A PubMed search was conducted. Inclusion criteria were: (1) time from trauma to surgery <12 months, (2) minimum follow-up one year, (3) intercostal to musculocutaneous nerve transfer the only surgical procedure performed to reestablish elbow flexion, and (4) males comprising more than 75% of cases. Two groups were created: Series from western countries, including America, Europe, and Africa; and series from Asia. Pearson correlation analysis was performed to assess for the degree of correlation between percent responders and mean national BMI. RESULTS: A total of 26 series were included, 14 from western countries and 12 from Eastern countries, encompassing a total of 274 and 432 surgical cases, respectively. The two groups were almost identical in mean age, but quite different in mean national BMI (26.3 vs. 22.5) and in the percentage of patients who achieved at least a Medical Research Council (MRC) level 3 (59.5% vs. 79.3%). Time from trauma to surgery was slightly shorter in Eastern (3.4 months) versus Western countries (5.0 months). CONCLUSIONS: The percentage of responders to intercostal to musculocutaneous nerve transfer was inversely correlated with the mean national BMI among male residents of the country where the series was performed.

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The increased number of musculoskeletal injuries can be caused by the lack attention to load level, as well as the posture and time of execution of an overloaded exercise. This way, the objective of this study was to analyze the effect of repetitive barbell biceps curl exercise over biceps brachii and erector spinae muscle electromyographic parameters. Ten healthy male subjects (20,91±1,37 years), without musculoskeletal diseases, performed the biceps curl exercise until fatigue, with 25%, 35% and 45% of 1 repetition maximum. The electromyographic activity of biceps brachii and erector spinae muscles was analyzed during isometric contraction performed before and immediately after fatiguing tests. The muscular fatigue was identified through the increase of root mean square and decrease of median frequency during isometric contractions. The results demonstrated these characteristics of fatigue after fatiguing test (p<0,05) for both muscles, showing a relationship time-load dependent for these electromyographic parameters. No significant differences were found between left and right muscles in the parameters analyzed. The experimental procedures allowed identify the muscular fatigue on biceps brachii muscles and erector spinae activity during barbell biceps curl and the dependence with load and number of repetition...

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