Sex disparities of human neuromuscular decline in older humans.

Females typically live longer than males but, paradoxically, spend a greater number of later years in poorer health. The neuromuscular system is a critical component of the progression to frailty, and motor unit (MU) characteristics differ by sex in healthy young individuals and may adapt to ageing in a sex-specific manner due to divergent hormonal profiles. The purpose of this study was to investigate sex differences in vastus lateralis (VL) MU structure and function in early to late elderly humans. Intramuscular electromyography signals from 50 healthy older adults (M/F: 26/24) were collected from VL during standardized submaximal contractions and decomposed to quantify MU characteristics. Muscle size and neuromuscular performance were also measured. Females had higher MU firing rate (FR) than males (P = 0.025), with no difference in MU structure or neuromuscular junction transmission (NMJ) instability. All MU characteristics increased from low- to mid-level contractions (P < 0.05) without sex × level interactions. Females had smaller cross-sectional area of VL, lower strength and poorer force steadiness (P < 0.05). From early to late elderly, both sexes showed decreased neuromuscular function (P < 0.05) without sex-specific patterns. Higher VL MUFRs at normalized contraction levels previously observed in young are also apparent in old individuals, with no sex-based difference of estimates of MU structure or NMJ transmission instability. From early to late elderly, the deterioration of neuromuscular function and MU characteristics did not differ between sexes, yet function was consistently greater in males. These parallel trajectories underscore the lower initial level for older females and may offer insights into identifying critical intervention periods. KEY POINTS: Females generally exhibit an extended lifespan when compared to males, yet this is accompanied by a poorer healthspan and higher rates of frailty. In healthy young people, motor unit firing rate (MUFR) at normalized contraction intensities is widely reported to be higher in females than in age-matched males. Here we show in 50 people that older females have higher MUFR than older males with little difference in other MU parameters. The trajectory of decline from early to late elderly does not differ between sexes, yet function is consistently lower in females. These findings highlight distinguishable sex disparities in some MU characteristics and neuromuscular function, and suggest early interventions are needed for females to prevent functional deterioration to reduce the ageing health-sex paradox.

Reliability of transcranial magnetic stimulation-evoked responses on knee extensor muscles during cycling.

Transcranial magnetic stimulation (TMS) measures the excitability and inhibition of corticomotor networks. Despite its task-specificity, few studies have used TMS during dynamic movements and the reliability of TMS paired pulses has not been assessed during cycling. This study aimed to evaluate the reliability of motor evoked potentials (MEP) and short- and long-interval intracortical inhibition (SICI and LICI) on vastus lateralis and rectus femoris muscle activity during a fatiguing single-leg cycling task. Nine healthy adults (2 female) performed two identical sessions of counterweighted single-leg cycling at 60% peak power output until failure. Five single pulses and ten paired pulses were delivered to the motor cortex, and two maximal femoral nerve stimulations (Mmax) were administered during two baseline cycling bouts (unfatigued) and every 5 min throughout cycling (fatigued). When comparing both baseline bouts within the same session, MEP·Mmax-1 and LICI (both ICC: >0.9) were rated excellent while SICI was rated good (ICC: 0.7-0.9). At baseline, between sessions, in the vastus lateralis, Mmax (ICC: >0.9) and MEP·Mmax-1 (ICC: 0.7) demonstrated good reliability; LICI was moderate (ICC: 0.5), and SICI was poor (ICC: 0.3). Across the fatiguing task, Mmax demonstrated excellent reliability (ICC > 0.8), MEP·Mmax-1 ranged good to excellent (ICC: 0.7-0.9), LICI was moderate to excellent (ICC: 0.5-0.9), and SICI remained poorly reliable (ICC: 0.3-0.6). These results corroborate the cruciality of retaining mode-specific testing measurements and suggest that during cycling, Mmax, MEP·Mmax-1, and LICI measures are reliable whereas SICI, although less reliable across days, can be reliable within the same session.

Immediate effect of local vibration on motor unit firing behavior and muscle strength in healthy young adult males.

PURPOSE: The aim of this study was to examine the effect of vibration on motor unit (MU) firing behavior and physical performance of antagonist muscles in healthy young adult males. METHODS: Fourteen males (age = 24.3 ± 3.6 years) were included in this study. There were two conditions, one in which participants received 80 Hz vibration in the distal tendon of the hamstring for 30 s and the control condition (no vibration). High-density surface electromyography (HD-SEMG) signals and maximal voluntary contraction (MVC) of knee extensor muscles were evaluated before and after the respective conditions and recorded from the vastus lateralis muscle during submaximal ramp-up and sustained contractions at 30% MVC. Convolution blind source separation was used to decompose the HD-SEMG signals into individual MU firing behaviors. RESULTS: In total, 739 MUs were detected (control; 360 MUs and vibration; 379 MUs), and a total of 312 matched MUs were identified across both submaximal contraction conditions (control: 150 MUs; vibration: 162 MUs). Vibration significantly increased the discharge rate (p = 0.047) and decreased the recruitment threshold before and after intervention (p = 0.001) but not in the control condition. Furthermore, the recruitment threshold is a factor that influences discharge rate. Significant correlations were observed between the recruitment threshold and both the ∆ discharge rate and the ∆ recruitment threshold under the vibration condition (p < 0.001). CONCLUSION: Vibration increased in the discharge rate and decreased the recruitment threshold of the antagonist muscle. These findings suggested that vibration contributes to immediate changes in the neural control of antagonist muscles.

Methodological considerations on near-infrared spectroscopy derived muscle oxidative capacity.

PURPOSE: Different strategies for near-infrared spectroscopy (NIRS)-derived muscle oxidative capacity assessment have been reported. This study compared and evaluated (I) approaches for averaging trials; (II) NIRS signals and blood volume correction equations; (III) the assessment of vastus lateralis (VL) and tibialis anterior (TA) muscles in two fitness levels groups. METHODS: Thirty-six participants [18 chronically trained (CT: 14 males, 4 females) and 18 untrained (UT: 10 males, 8 females)] participated in this study. Two trials of twenty transient arterial occlusions were performed for NIRS-derived muscle oxidative capacity assessment. Muscle oxygen consumption ( V ˙ O2m) was estimated from deoxygenated hemoglobin (HHb), corrected for blood volume changes following Ryan (HHbR) and Beever (HHbB) equations, and from oxygen saturation (StO2) in VL and TA. RESULTS: Superimposing or averaging V ˙ O2m or averaging the rate constants (k) from the two trials resulted in equivalent k values [two one-sided tests (TOST) procedure with 5% equivalence margin-P < 0.001]. Whereas HHbR (2.35 ± 0.61 min-1) and HHbB (2.34 ± 0.58 min-1) derived k were equivalent (P < 0.001), StO2 derived k (2.81 ± 0.92 min-1) was greater (P < 0.001) than both. k values were greater in CT vs UT in both muscles (VL: + 0.68 min-1, P = 0.002; TA: + 0.43 min-1, P = 0.01). CONCLUSION: Different approaches for averaging trials lead to similar k. HHb and StO2 signals provided different k, although different blood volume corrections did not impact k. Group differences in k were detected in both muscles.

Management of a Complex, Recurrent Case of Medial Thigh Sarcoma With Pedicled Deep Inferior Epigastric Artery Perforator (DIEP) Lymphatic Flow-Through (LyFT) Flap and Secondary Anterolateral Thigh (ALT) Free Flap With Innervated Vastus Lateralis Anastomosed to Synthetic Artery Graft: A Case Report.

Soft-tissue sarcomas (STS) are rare solid tumors of mesenchymal cell origin and account for only 1% of adult malignancies. They tend to occur most commonly in the lower extremities. Reconstruction after sarcoma resection can be challenging, especially when important structures are involved and recurrences occur. Additionally, more attention is now being paid to reconstructing the lymphatic system to prevent lymphatic complications. In this case report, we presented the management of recurrent medial thigh sarcoma that necessitated multiple challenging reconstructions to provide valuable insights for lectures on similar cases. A 50-year-old male patient was diagnosed with an undifferentiated pleomorphic cell sarcoma (UPS) of the anteromedial thigh. After preoperative radiotherapy, a mass of 23 × 15 cm was removed, and reconstruction with a pedicled deep inferior epigastric artery perforator (p-DIEP) flap-based lymphatic flow through (LyFT) was performed. Six months later, the patient developed the first local recurrence with the presence of a distant metastasis. Following the tumor resection, the medial part of the DIEP flap was de-epithelized and buried in the defect for dead space obliteration. Another local recurrence arose 7 months after the second surgery. Therefore, a major debulking surgery involving the femoral neurovascular bundle was performed. The femoral artery was reconstructed with a synthetic graft, and the femoral vein with the great saphenous vein harvested from the contralateral thigh. A composite myocutaneous neurotized anterolateral thigh (ALT) flap from the contralateral thigh was used to obliterate the defect and restore the loss of function of the quadriceps femoris. Two lymphaticovenular anastomoses (LVAs) were performed at the ankle to reduce the risk of lymphatic sequelae. This case report highlights the importance of integrating various techniques to create a tailored approach that effectively addresses complex surgical requirements to avoid limb amputation and maintain functionality.

Combining antibiotic-loaded bone cement-based free vastus lateralis muscle-sparing flap with split-thickness skin grafts: A reliable strategy for reconstructing diabetic foot ulcers at non-weight-bearing areas.

Diabetic foot ulcers (DFUs) present significant challenges due to their associated amputation rates, mortality, treatment complexity and excessive costs. Our earlier work introduced a wound surgical integrated treatment (WSIT) for DFUs, yielding promising outcomes. This study focuses on a specific WSIT protocol employing antibiotic-loaded bone cement (ALBC) in the first Stage, and free vastus lateralis muscle-sparing (VLMS) flaps and split-thickness skin grafts (STSGs) in the second stage to repair non-weight-bearing DFUs. From July 2021 to July 2023, seven DFU patients (aged 47-71 years) underwent this treatment. Demographic data, hospital stay and repair surgery times were collected. Histological and immunohistochemical analyses assessed angiogenesis, collagen deposition and inflammation. SF-36 questionnaire measured pre- and postoperative quality of life. Preoperative ultrasound Doppler showed that the peak blood flow velocity of the recipient area artery was significantly >30 cm/s (38.6 ± 6.8 cm/s) in all patients. Muscle flap sizes varied from 8 × 3.5 × 1 to 18 × 6 × 2 cm. The operation time of the repair surgery was 156.9 ± 15.08 minutes, and the hospital stay was 18.9 ± 3.3 days. Histological analysis proved that covering DFUs with ALBC induced membrane formation and increased collagen, neovascularization and M2 macrophages fraction while reducing M1 macrophages one. All grafts survived without amputation during a 7- to 24-month follow-up, during which SF-36 scores significantly improved. A combination of ALBC with free VLMS flaps and STSGs proved to be safe and effective for reconstructing non-weight-bearing DFUs. It rapidly controlled infection, enhanced life quality and foot function, and reduced hospitalization time. We advocate integrating this strategy into DFU treatment plans.

The effects of crank power and cadence on muscle fascicle shortening velocity, muscle activation and joint-specific power during cycling.

Whilst people typically choose to locomote in the most economical fashion, during bicycling they will, unusually, chose cadences that are higher than metabolically optimal. Empirical measurements of the intrinsic contractile properties of the vastus lateralis (VL) muscle during submaximal cycling suggest that the cadences that people self-selected might allow for optimal muscle fascicle shortening velocity for the production of knee extensor muscle power. It remains unclear, however, whether this is consistent across different power outputs where the self-selected cadence (SSC) varies. We examined the effect of cadence and external power requirements on muscle neuromechanics and joint power during cycling. VL fascicle shortening velocity, muscle activation and joint-specific power were measured during cycling between 60 and 120 rpm (including SSC), while participants produced 10%, 30% and 50% of peak maximal power. VL shortening velocity increased as cadence increased but was similar across the different power outputs. Although no differences were found in the distribution of joint power across cadence conditions, the absolute knee joint power increased with increasing crank power output. Muscle fascicle shortening velocity increased in VL at the SSC as pedal power demands increased from submaximal towards maximal cycling. A secondary analysis of muscle activation patterns showed minimized activation of VL and other muscles near the SSC at the 10% and 30% power conditions. Minimization of activation with progressively increasing fascicle shortening velocities at the SSC may be consistent with the theory that the optimum shortening velocity for maximizing power increases with the intensity of exercise and recruitment of fast twitch fibers.

In vivo absolute quantification of carnosine in the vastus lateralis muscle with 1H MRS using a surface coil and water as internal reference.

OBJECTIVE: To standardize a method for 1H MRS intramuscular absolute quantification of carnosine in the thigh, using a surface coil and water as internal reference. MATERIALS AND METHODS: Carnosine spectra were acquired in phantoms (5, 10, and 15 mM) as well as in the right gastrocnemius medialis (GM) and right vastus lateralis (VLM) muscles of young team sports athletes, using volume (VC) and surface (SC) coils on a 3 T scanner, with the same receiver gain. Water spectra were used as internal reference for the absolute quantification of carnosine. RESULTS: Phantom's experiments showed a maximum error of 7%, highlighting the validity of the measurements in the study setup. The carnosine concentrations (mmol/kg ww, mean ± SD) measured in the GM were 6.8 ± 2.2 with the VC (CcarVC) and 10.2 ± 3.0 with the SC (CcarSC) (P = 0.013; n = 9). Therefore, a correction was applied to these measurements (CcarVC = 0.6582*CcarSC), to make coils performance comparable (6.8 ± 2.2 for VC and 6.7 ± 2.0 for SC, P = 0.97). After that, only the SC was used to quantify carnosine in the VLM, where a concentration of 5.4 ± 1.5 (n = 30) was found, with significant differences between men (6.2 ± 1.3; n = 15) and women (4.6 ± 1.2; n = 15). The error in quantitation was 5.3-5.5% with both coils. CONCLUSION: The method using the SC and water as internal reference can be used to quantify carnosine in voluminous muscles and regions of the body in humans, where the VC is not suitable, such as the VLM.

Multipartite patella: A review of diagnostic techniques and management of the symptomatic patient.

Multipartite patella is an anatomical variant classified by the fragmentation of the main patellar body. The cause of this variant is due to failure in fusion of the patellar ossification centers. It is commonly misdiagnosed as a fracture of the patella in clinical practice, leading to unnecessary treatment measures. The aim of this review is to provide an overview of the development and classification of this variation, diagnostic imaging techniques, and assess the optimal management technique for the symptomatic patient. Multiple radiographic methods are used to identify this variant, with recent studies highlighting high sensitivity rates for nonradiative methods (ultrasound). In terms of symptomatic management, accessory fragment excision and vastus lateralis release provide the greatest alleviation of symptoms, with screw fixation being less favorable.

Muscle Fiber Conduction Velocity During Electrically Stimulated Contraction at Various Joint Angles, During Joint Movements, and During Voluntary Contractions.

Muscle fiber conduction velocity (MFCV) can be affected by muscle fiber geometry at different joint angles and during joint movements. This study aimed to investigate MFCV during electrically evoked contraction at different joint angles, during joint movements, and during voluntary contractions. Sixteen healthy young men participated. A stimulation electrode was attached on the innervation zone of the vastus lateralis, and a linear electrode array was attached on the vastus lateralis. Under a static condition, electrically evoked electromyography signals were recorded at knee joint angles set every 15° between 0° and 105°. Under a passive movement condition, signals were recorded during knee extension and flexion passively. Under a voluntary contraction condition, signals were recorded while performing 30% or 60% of maximum voluntary contraction. MFCV was calculated using cross-correlation coefficients. Under the static condition, there were no differences in MFCV among various joint angles. Under the passive movement condition, MFCV was significantly greater during high velocity or shortening. Under the voluntary contraction condition, MFCV was significantly greater during high-intensity voluntary contraction and with a shortened muscle length. Joint angles do not influence MFCV markedly during relaxation, but it is possible to overestimate MFCV during movement or voluntary contraction.

Secondary reconstruction of the orbit and conjunctival sac - a case report.

The authors present a novel modification of vastus lateralis muscle free flap based orbital reconstruction in a 41-year-old patient, with a secondary defect to an injury with technical oil under high pressure. The patient underwent multiple reconstructive procedures in different medical centers with poor functional and esthetic results including simple local plasty techniques. The patient underwent simultaneous reconstruction of the soft tissues of the orbit, and conjunctival sac based on a prelaminated vastus lateralis free flap. The two-stage reconstruction of these structures is beneficial both for the patient's psychical and mental condition and for health system finances. Therefore, whenever it's possible, we should try to decrease the number of required procedures. The authors believe that their technique can significantly improve the quality of life of patients after exenteration but simultaneously they emphasize the need to carry out more procedures in order to refine it.

Optimal stimulation site of the femoral nerve to record F waves from the vastus lateralis muscle.

INTRODUCTION/AIMS: The conventional recording of F waves from the vastus lateralis muscle (VL) may not accurately measure the F-wave amplitude, as the F-wave latency is short and overlaps with the M wave. However, the optimal stimulation site of the femoral nerve for recording M and F waves separately from the VL remains unclear. In this study we aimed to determine the optimal stimulation site of the femoral nerve to record M and F waves separately from the VL. METHODS: Stimulating electrodes were placed medial and lateral to the VL (50%, 60%, 70%, and 80% of the distance along a line extending from the proximal to the distal thigh). Each site of the distal thigh was electrically stimulated at random and F waves were recorded from the VL. Each stimulation site was considered to be success if there was no severe pain or discomfort during electrical stimulation of the femoral nerve and no overlap between the recorded M and F waves; otherwise, it was determined as a failure. RESULTS: Thirteen healthy men participated in the study. F waves were successfully recorded in five participants at the 50% sites, eight participants at the 60% site, and 12 participants at the 70% and 80% sites. In cases of failed F-wave measurement, the participants experienced severe pain or discomfort due to electrical stimulation. DISCUSSION: M and F waves could be recorded separately from the VL when the relevant branch of the femoral nerve was stimulated in the distal thigh.

Pedicled vastus lateralis myocutaneous flap for sacropelvic defects after wide oncologic resection: Wound complications and outcomes.

BACKGROUND AND OBJECTIVES: Adequate coverage of the soft tissue defects from wide resection of sacropelvic malignancies remains challenging. The vastus lateralis flap has been described for coverage in the setting of trauma and infection. This flap has not been described for coverage of sacropelvic tumor defects. METHODS: This is a retrospective cohort study of adult patients who underwent wide resection of a primary sacropelvic malignancy with reconstruction employing a pedicled vastus lateralis flap at two tertiary care centers. Patient demographics, tumor staging, and rate of complications were assessed. RESULTS: Twenty-eight patients were included, with a median age of 51 years. The most common primary tumor was chondrosarcoma followed by chondroblastic osteosarcoma. The median follow-up was 1.1 years. There were 10 cases of wound infection requiring re-operation and three cases of flap failure. CONCLUSIONS: We describe a pedicled vastus lateralis flap for coverage of defects after wide resection of sacropelvic malignancies. A large proportion of our cohort had independent risk factors for wound complications. Even with a cohort with high baseline risk for wound complications, we show that the use of a pedicled vastus lateralis flap is a safe reconstructive option with a wound complication rate in line with the literature.

Effects of continuous cycling training on motor unit firing rates, input excitation, and myosin heavy chain of the vastus lateralis in sedentary females.

This study examined the effects of continuous endurance training on motor unit (MU) mean firing rates (MFR), percent myosin heavy chain (%MHC) isoforms, and muscle cross-sectional area (mCSA) of the vastus lateralis (VL). Twelve females completed 5-weeks of continuous cycling-training (CYC), while 8 females were controls (CON). Participants performed maximal voluntary contractions (MVCs) and 40% MVCs of the knee extensors before (PRE) and after the 5-week treatment period at the same absolute pre-treatment submaximal torque (POSTABS) and relative to post-treatment MVCs (POSTREL). Surface electromyographic (EMG) signals were decomposed with the Precision Decomposition III algorithm. MU firing times and waveforms were validated with reconstruct-and-test and spike trigger average procedures. MFRs at steady torque, recruitment thresholds (RT), and normalized EMG amplitude (N-EMGRMS) were analyzed. Y-intercepts and slopes were calculated for the MFR vs. RT relationships. MHC isoforms and mCSA were determined with muscle biopsies and ultrasonography. CYC decreased MVCs and type IIX %MHC isoform without changes in mCSA. The slopes for the MFR vs. RT relationships decreased for CYC during POSTREL and POSTABS while N-EMGRMS increased for POSTABS with no differences between PRE and POSTREL. Type I %MHC isoform was correlated with the slope for the MFR vs. RT relationship during POSTABS and POSTREL for CYC. This study provides evidence that decreases in the MFRs of higher threshold MUs post-CYC is likely a function of changes in input excitation (POSTABS) and the firing frequency-excitation relationships (POSTREL). Evidence is provided that MHC isoforms influence the firing rate scheme of the muscle following short-term training.

Method of analysis influences interpretations of sex-related differences in firing rates during prolonged submaximal isometric contractions.

OBJECTIVE: This study examined motor unit (MU) firing rates during a prolonged isometric contraction of the vastus lateralis (VL) for females and males. METHODS: Surface electromyographic (sEMG) signals were recorded from the VL for eleven females and twelve males during a 45-second isometric trapezoid muscle actions at 40% of maximal voluntary contraction (MVC). For each MU, mean firing rate (MFR) was calculated for the initial and final 10-second epochs of the steady torque segment and regressed against recruitment threshold (RT, expressed as %MVC), as well as time at recruitment (TREC, seconds). MFR was also averaged for each subject. RESULTS: Significant differences existed across epochs for the y-intercepts (P=0.009) of the MFR vs. TREC relationship, as well as the grouped MFR analysis (P<0.001); no differences were observed between epochs for the MFR vs. RT relationship. Significant differences existed between sexes for the grouped MFR analysis (P=0.049), but no differences were observed for the MFR vs. TREC or MFR vs. RT relationships. CONCLUSION: Analysis method may impact interpretation of firing rate behavior; increases in MU firing rates across a prolonged isometric contraction were observed in the MFR vs. TREC relationship and the grouped MFR analysis.

The influence of chronic training status on the mechanical behavior of the vastus lateralis during repetitive trapezoidal contractions.

OBJECTIVES: To examine maximal strength and fatigability of the knee extensors, and mechanomyographic amplitude (MMGRMS)-force relationships of the vastus lateralis (VL) during repetitive muscle actions for 5 aerobically-(AT), 5 resistance-trained-(RT), and 5 sedentary (SED) individuals. METHODS: Participants performed maximal voluntary contractions before (MVCPRE) and after (MVCPOST) attempting 20 isometric trapezoidal muscle actions at 50% MVCPRE. MMG was recorded from the VL. b terms (slopes) were calculated from the natural log-transformed MMGRMS-force relationships for each participant (increasing and decreasing segments). MMGRMS was averaged during steady force. RESULTS: RT had greater MVCPRE (P<0.001) and MVCPOST (P=0.001-0.004) than AT and SED. Only AT completed 20 muscle actions and exhibited no decrease in MVCPOST (P=0.149). The b terms were greater for RT than AT during the increasing segment of the first contraction (P=0.001) and decreasing segment of the last contraction (P=0.033). The b terms were also greater for RT (P=0.006) during the increasing than decreasing segment for the first contraction. MMGRMS during steady force was greater during the last contraction when collapsed across training status (P=0.021). CONCLUSION: Knee extensor MVC and fatigability, and motor unit control strategies for the VL during a series of repetitive contractions were influenced by chronic training status.

The skeletal muscle microbiopsy method in exercise and sports science research: A narrative and methodological review.

BACKGROUND: The skeletal muscle microbiopsy protocol was introduced to the Exercise and Sports Science (ESS) research field in 1999 and has been used as a protocol to directly examine muscular structural and biochemical changes. There is much variation in the reporting of the microbiopsy protocol and its related pre- and post-procedure for participant care and sample collection. The purpose of this narrative and methodological review is to compare the microbiopsy to the traditional Bergström protocol used in the ESS field, identify and summarize all related microbiopsy protocols used in previous ESS studies and determine the most frequently used microbiopsy protocols aspects and associated pre- and post-biopsy procedures. METHODS: A review of literature up to January 2022 was used following the PRISMA and Cochrane Methodological Review Guide to determine frequently used methods that may facilitate optimal and potential recommendations for muscle microbiopsy needle gauge (G), concentration or dose (% or ml) and administration of local anesthetic, co-axial/cannula introducer gauge (G), muscle depth (cm), muscle sample size collected (mg), passes to collect samples, time points of muscle sampling, and promotion of participant compliance and minimization of adverse events. RESULTS: Eighty-five articles were selected based on the inclusionary requirements related to the ESS field or methodological considerations. The most frequently reported aspects in previous research to suggest the location of the vastus lateralis is the midpoint between the patella and the greater trochanter of the femur or 1/3 or 2/3 the distance from the patella to anterior superior iliac spine, 14 G biopsy needle, subcutaneous injected lidocaine administration (2 ml, 1%), 13 G co-axial/cannula, 1-2 cm muscle depth, 10-20 mg of muscle sample, ~3-time points, and 2-3 passes. DISCUSSION: There is much variation in the reporting of the microbiopsy protocol and its related pre- and post-biopsy procedures. Standardization in reporting may promote recommendations to optimize data integrity, participant safety, participant adherence to the study design, and increase reproducibility. Recommendations are made for the microbiopsy procedure based on frequently reported characteristics.

Laterality of the activation of the vastus lateralis muscle in females with Parkinson's disease during the medication state compared with healthy controls.

The aim of this study was to quantify the laterality of motor unit (MU) activation properties in people with Parkinson's disease (PD) during force production (low- to high-intensity contraction) using high-density surface electromyography (HD-SEMG). Sixteen females with PD (age = 69.9 ± 7.6 years, disease duration = 4.9 ± 5.1 years) and 14 healthy female subjects (age = 68.6 ± 3.6 years) were enrolled in the study and performed submaximal ramp-up contractions during isometric knee extension. HD-SEMG signals were recorded from both vastus lateralis muscles. We calculated the level of heterogeneity in the spatial distribution patterns of the HD-SEMG signals and determined the modified entropy, coefficient of variation of the root mean square (RMS), and correlation coefficient to evaluate MU activation properties. Pearson's correlation coefficients were calculated to examine the relationships between disease severity and the RMS and EMG variables. The RMS value and heterogeneity were significantly higher and lower on the more-affected side in people with PD than on the other side in people with PD or either side in control subjects (p < 0.05). People with PD exhibited the temporal changes of spatial MUs activation properties showed significant laterality when compared to healthy control subjects not only in the low-intensity contractions but also in high-intensity contraction. Moderate-to-strong correlations were observed between disease severity and RMS and EMG variables in people with PD (r > 0.6, p < 0.001). We compared the laterality of MU activation properties between the people with PD and the control subjects. These findings suggest that people with PD have asymmetrical MU activation properties, regardless of the magnitude of force production.

Vastus lateralis versus rectus femoris muscle flaps for recalcitrant hip joint infection: An anatomical study comparing the effectiveness of acetabular dead space control.

Eliminating recalcitrant prosthetic hip joint infections remains one of the greatest challenges in orthopedic surgery. In such cases, the salvage procedure of femoral head excision (the Girdlestone procedure) is often performed. There has been emerging surgical interest in filling the resulting acetabular dead space with a pedicled muscle flap, to enable antibiotic delivery. Both vastus lateralis (VL) and rectus femoris (RF) muscle flaps have been described for this purpose with good success. This study is the first anatomical investigation comparing VL and RF as candidates for interposition myoplasty following hip joint excision. Following standard surgical technique, the Girdlestone procedure and interposition myoplasty of both RF and VL were performed on 10 cadavers. The primary aim was to determine which muscle flap eliminated a greater volume of acetabular dead space. Secondary aims were to characterize the blood supply to RF and assess additional metrics indicative of the likelihood of flap success. The VL flap eliminated more dead space than RF. However, the use of the RF flap was feasible in all cases and has several benefits, including ease of harvest, mobility, and aesthetics. The location of the inferior vascular pedicle into RF was relatively consistent and the most effective predictor of flap success. Both VL and RF are effective in reducing acetabular dead space. While VL can fill a greater volume, the RF flap has technical advantages, related to the predictability of the blood supply.

Reconstruction of nasal airway in patients of class IIId maxillary defect with vastus lateralis muscle-chimeric double skin paddle ALT flap.

BACKGROUND: A reconstructive challenge in patients with class IIId maxillary defect is how to obliterate the defect and restore a patent nasal airway. The current strategy using the single anterolateral thigh (ALT) fasciocutaneous flap for reconstruction may result in permanent mouth breathing. As the ALT flap was a common option in reconstruction processes, this study aimed to evaluate the benefits of vastus lateralis (VL) muscle-chimeric double skin paddle ALT flap in simultaneous defect and nasal airway reconstruction. METHODS: This study included 21 patients with class IIId maxillary defect who underwent free ALT flap reconstruction (n = 11, single ALT flap group; n = 10, VL muscle-chimeric double skin paddle ALT flap (chimeric ALT flap) group) at the China Medical University Hospital from August 2015 to September 2019. Associated parameters collected for analysis included gender, age, body mass index (BMI), operative time, hospitalization, clinical stage, preoperative treatment, flap/defect size, comorbidities, postoperative RT, mouth breathing and short/long term complications. RESULTS: No significant differences were observed in age, BMI, hospitalization, clinical stage, preoperative treatment, defect size, comorbidities, and postoperative RT between the two groups; however, the chimeric ALT flap group as dominated by male patients (p = 0.009), and had longer operative times (12.1 h vs. 10.1 h, p = 0.002) and larger flap sizes (180 cm2 vs. 96.7 cm2, p = 0.013). Compared with the chimeric ALT flap group, the single ALT flap group suffered from permanent mouth breathing. CONCLUSION: Nasal airway reconstruction should be considered in patients with class IIId maxillary defect. Compared to the single ALT flap, the chimeric ALT flap is a superior reconstructive option for patients with class IIId maxillary defect, although a longer surgical duration and larger flap size are required.