Innervated vastus lateralis muscle: complementing and completing the anterolateral thigh flap for abdominal wall reconstruction.

Reconstruction of composite abdominal wall defects is challenging. An anterolateral thigh (ALT) flap has established itself in the algorithm for abdominal wall reconstruction. Augmenting innervated vastus lateralis (iVL) muscle to ALT has added advantages. We describe previously unreported advantage of ALT with iVL.A woman in her 30s, suffering from Mullerian adenocarcinoma with metastasis to the right anterior abdominal wall and right inguinal lymph node, was taken for wide local excision and reconstruction. After excision, there was a 15×12 cm defect of the anterior abdominal wall. We reconstructed the defect with prosthetic mesh and pedicled composite ALT and iVL. There was venous congestion in the ALT flap and it could not be salvaged. We debrided the ALT flap and applied split skin graft over iVL. The grafted and donor sites healed well. The patient was able to do moderate strenuous activities. The presence of iVL allowed us to get away with minor procedure and averted the need for another flap.

The effects of resistance training on denervated myofibers, senescent cells, and associated protein markers in middle-aged adults.

Denervated myofibers and senescent cells are hallmarks of skeletal muscle aging. However, sparse research has examined how resistance training affects these outcomes. We investigated the effects of unilateral leg extensor resistance training (2 days/week for 8 weeks) on denervated myofibers, senescent cells, and associated protein markers in apparently healthy middle-aged participants (MA, 55 ± 8 years old, 17 females, 9 males). We obtained dual-leg vastus lateralis (VL) muscle cross-sectional area (mCSA), VL biopsies, and strength assessments before and after training. Fiber cross-sectional area (fCSA), satellite cells (Pax7+), denervated myofibers (NCAM+), senescent cells (p16+ or p21+), proteins associated with denervation and senescence, and senescence-associated secretory phenotype (SASP) proteins were analyzed from biopsy specimens. Leg extensor peak torque increased after training (p < .001), while VL mCSA trended upward (interaction p = .082). No significant changes were observed for Type I/II fCSAs, NCAM+ myofibers, or senescent (p16+ or p21+) cells, albeit satellite cells increased after training (p = .037). While >90% satellite cells were not p16+ or p21+, most p16+ and p21+ cells were Pax7+ (>90% on average). Training altered 13 out of 46 proteins related to muscle-nerve communication (all upregulated, p < .05) and 10 out of 19 proteins related to cellular senescence (9 upregulated, p < .05). Only 1 out of 17 SASP protein increased with training (IGFBP-3, p = .031). In conclusion, resistance training upregulates proteins associated with muscle-nerve communication in MA participants but does not alter NCAM+ myofibers. Moreover, while training increased senescence-related proteins, this coincided with an increase in satellite cells but not alterations in senescent cell content or SASP proteins. These latter findings suggest shorter term resistance training is an unlikely inducer of cellular senescence in apparently healthy middle-aged participants. However, similar study designs are needed in older and diseased populations before definitive conclusions can be drawn.

Clinical-Like Cryotherapy in Acute Knee Arthritis Protects Neuromuscular Junctions of Quadriceps and Reduces Joint Inflammation in Mice.

Rheumatoid arthritis is an autoimmune and inflammatory disease that affects synovial joint tissues and skeletal muscle. Clinical-like cryotherapy benefits signs of joint inflammation in knee osteoarthritis after 60 days of anterior cruciate ligament transection surgery. However, it is unknown whether it also benefits acute knee arthritis (e.g., reduces inflammatory process and protects neuromuscular junction [NMJ] and muscle fibers). We aimed to analyze the effects of clinical-like cryotherapy on NMJ and quadriceps muscle fibers in a model of acute knee arthritis. Twenty-four male C57BL/6 mice (20 to 25 g) were randomly allocated into three groups: control (mice with no intervention), antigen-induced arthritis (AIA; mice sensitized and immunized with intra-articular [i.a.] injection of methylated bovine serum albumin [mBSA]), and AIA+cryotherapy (mice sensitized, immunized with i.a. injection of mBSA, and submitted to a clinical-like cryotherapy protocol). Twenty-one days after sensitization, arthritis was induced in immunized mice via i.a. injection of mBSA (100 µg/joint). Two clinical-like cryotherapy sessions (crushed ice pack for 20 min) were applied two hours apart. The first session was applied immediately after i.a. injection of mBSA. The quadriceps was removed two hours after the second clinical-like cryotherapy session for morphological analysis of muscle fibers (cross-sectional area), frequency distribution of muscle fiber area (%), and NMJ (area, perimeter, and maximum diameter). Gene expressions of mRNA involved in NMJ signaling (γ-nAChR, α1-nAChR, ε-nAChR, Agrin-MusK-Rapsyn, α-dystrobrevin, and utrophin) and atrophy (muscle RING-finger protein-1 and Atrogin-1) pathways were analyzed. Inflammatory signs were assessed in knee joint (swelling, articular surface temperature, and neutrophil migration in synovial fluid). Regarding morphological analysis of muscle fibers, 180 to 270 and >270 µm2 classes were higher in the AIA+cryotherapy than the AIA group. Area, perimeter, and maximum diameter of NMJ also increased in the AIA+cryotherapy compared with the control group. Agrin mRNA expression increased in the AIA+cryotherapy compared with the control and AIA groups. In the atrophy pathway, Atrogin-1 increased compared with the control and AIA groups. The AIA+cryotherapy group reduced knee swelling and neutrophil migration compared with the AIA group. In conclusion, clinical-like cryotherapy increased Agrin expression, contributing to NMJ maintenance and increased Atrogin-1 expression, thus protecting NMJ and muscle fiber. Furthermore, clinical-like cryotherapy reduced inflammatory signs (swelling and neutrophil migration) of acute knee arthritis.

The Effects of Nicotine on Cortical Excitability After Exercise: A Double-Blind Randomized, Placebo-controlled, Crossover Study.

PURPOSE: The use of smokeless tobacco/nicotine products is common among athletes, but clear evidence for their positive or negative effect on sports performance is lacking. Nicotine is a psychoactive substance involved in numerous neuronal processes including cortical excitability. The aim of this study was to evaluate its effect on cortical excitability associated with aerobic exercise in nicotine-naive healthy volunteers. METHODS: Ten nicotine-naive healthy volunteers were recruited for this double-blind, randomized, crossover study to compare the effect of snus (8 mg nicotine), an oral, smokeless tobacco product, to placebo on cortical excitability before and after aerobic exercise. Transcranial magnetic stimulation (TMS) was used to measure changes in corticomotor excitability (motor-evoked potentials, MEPs) and electromyography of leg muscles during maximal voluntary contractions (MVC) to assess changes in muscle contractions. Before and after aerobic exercise and with or without nicotine treatment, MEPs and MVCs were measured. RESULTS: Analysis of TMS data showed lower motor cortex activation (lower MEP amplitude) after snus administration compared with placebo, whereas electromyography data showed no difference in muscle contraction between snus and placebo treatment. CONCLUSIONS: These findings suggest a general reduction in cortical excitability, without no relevant effect on physical performance.

Absence of an aging-related increase in fiber type grouping in athletes and non-athletes.

The aging-related loss of muscle mass is thought to be partly attributable to motor neuron loss and motor unit remodeling that result in fiber type grouping. We examined fiber type grouping in 19- to 85-year-old athletes and non-athletes and evaluated to which extent any observed grouping is explained by the fiber type composition of the muscle. Since regular physical activity may stimulate reinnervation, we hypothesized that fiber groups are larger in master athletes than in age-matched non-athletes. Fiber type grouping was assessed in m. vastus lateralis biopsies from 22 young (19-27 years) and 35 healthy older (66-82 years) non-athletes, and 14 young (20-29 years), 51 middle-aged (38-65 years), and 31 older (66-85 years) athletes. An "enclosed fiber" was any muscle fiber of a particular type surrounded by fibers of the same type only. A fiber type group was defined as a group of fibers with at least one enclosed fiber. Only type II fiber cross-sectional area (FCSA) showed an age-related decline that was greater in athletes (P < .001) than in non-athletes (P = .012). There was no significant age-related effect on fiber group size or fiber group number in athletes or non-athletes, and the observed grouping was similar to that expected from the fiber type composition. At face value, these observations do 1) neither show evidence for an age-related loss and remodeling of motor units nor 2) improved reinnervation with regular physical activity, but 3) histological examination may not reveal the full extent of aging-related motor unit remodeling.

Combined Application of Electrically Stimulated Antagonist Muscle Contraction and Volitional Muscle Contraction Prevents Muscle Strength Weakness and Promotes Physical Function Recovery After Total Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Osteoarthritis of the knee (KOA) is the most common cause of disability in both the United States and in Japan. The Hybrid training system (HTS) has been developed as a resistance exercise method combining electrical stimulation with voluntary exercise. The purpose of the present study is to compare the effects of a conventional rehabilitation program with or without HTS on knee muscle strength and physical function after Total knee arthroplasty (TKA). METHODS: We conducted a 12-week randomized controlled trial, using standard rehabilitation (the control group, n = 27) or standard rehabilitation plus HTS (the HTS group, n= 26), in 53 female patients after TKA. The HTS group underwent HTS three times per week for twelve weeks after TKA. Muscle strength, thigh circumference, physical functional testing, QOL and knee pain were assessed before surgery, 6 and 12 weeks after TKA. RESULTS: There was a significant decrease in quadriceps strength and thigh circumference on the operative side in the control group, but not in the HTS group at 6 weeks. Hamstring strength on the operative side in the HTS group significantly increased and thigh circumference was bigger than in the control group at 12 weeks. Physical function improved at 6 weeks in the HTS group, but not in the control group. Knee pain significantly improved in both groups at 6 weeks. CONCLUSIONS: HTS was effective in preventing quadriceps weakness and in improving physical function and QOL after TKA.

Localización biométrica de los puntos motores del músculo cuádriceps femoral de individuos brasileños / Biometric localization of the motor points of the femoral quadriceps muscle of Brazilian individuals

El músculo cuadríceps femoral es un músculo que participa principalmente en los movimientos de la rodilla y también en la cadera, pudiendo ser afectado por alteraciones en el trofismo muscular, tras lesiones de estas articulaciones o afecciones en el tono muscular, como la espasticidad, tras lesiones cerebrovasculares. Cada una de sus cabezas está inervada por ramos del nervio femoral. El presente estudio tuvo por objetivo la identificación y medición de la distancia de los puntos motores (Pm) del músculo cuadríceps femoral, en relación a estructuras anatómicas de relevancia clínica. Se utilizaron 30 miembros inferiores de 23 cadáveres formolizados, de individuos brasileños adultos. El estudio fue realizado en la Universidade Estadual de Ciências da Saúde de Alagoas (UNCISAL), Maceió, Brasil. Se realizó la disección por planos en la zona medial, anterior y lateral del muslo, identificando a los ramos del nervio femoral para cada componente, músculos recto femoral (mRf), vasto medial (mVm), vasto intermedio (mVint) y vasto lateral (mVlat), localizando cada uno de los Pm. Las mediciones se realizaron con un cáliper marca Mitutoyo de 0,05 mm de precisión. Los datos obtenidos fueron tratados estadísticamente, utilizando para ello, el software STATA (versión 14.1). El mRf, tuvo un promedio de 2,45 ± 1,39 Pm, estando la gran mayoría de los Pm (63 %), en la zona distal del tercio proximal del muslo; el mVm presentó 4,42 ± 2,74 Pm en promedio, encontrándose el 41 % de ellos en el tercio medio del muslo, zona distal; el mVint tuvo 3,99 ± 2,34 Pm en promedio y el 58 % de ellos, se localizaron en la zona proximal del tercio medio del muslo; el mVlat presentó un promedio de 3,88 ± 2,37 Pm y el 50 % de éstos se encontraron en del tercio proximal del muslo. La localización biométrica de los Pm se informa en resultados. La ubicación biométrica de los Pm, favorecerá el quehacer, tanto clínico como quirúrgico, de la zona anterior del muslo.

The quadriceps femoris muscle is a muscle that participates mainly in the movements of the knee and also in the hip, being able to be affected by alterations in muscle trophism, after injuries of these joints or muscular tone conditions, such as spasticity, after injuries cerebrovascular. Each of its heads is innervated by branches of the femoral nerve. The objective of this study was to identify and measure the distance of the motor points (MP) of the quadriceps femoris muscle, in relation to anatomical structures of clinical relevance. Thirty lower limbs of 23 formolized corpses of adult Brazilian individuals were used. The study was conducted at the State University of Ciências da Saúde de Alagoas (UNCISAL), Maceió, Brazil. The dissection was performed by planes in the medial, anterior and lateral thigh, identifying the femoral nerve branches for each component, rectus femoris muscles (Rfm), medial vastus (mVm), vastus intermedius (intVm) and vastus lateralis ( latVm), locating each of the MP. The measurements were made with a Mitutoyo caliper of 0.05 mm accuracy. The data obtained were treated statistically, using the STATA software (version 14.1). The Rfm had an average of 2.45 ± 1.39 MP, the great majority of the MP (63 %) being in the distal area of the proximal third of the thigh; the mVm presented 4.42 ± 2.74 MP on average, with 41 % of them in the middle third of the thigh, distal zone; the intVm had 3.99 + 2.34 MP on average and 58 % of them were located in the proximal area of the middle third of the thigh; the latVm presented an average of 3.88 ± 2.37 MP and 50 % of these were found in the proximal third of the thigh. The biometric localization of the MP is reported in results. The biometric location of the MP, will favor the task, both clinical and surgical of the anterior thigh area.

Ramos de inervación y distribución del nervio femoral en el músculo cuádriceps femoral de individuos brasileños / Innervation branches and distribution of the femoral nerve in the quadriceps femoral muscle in Brazilian individuals

El nervio femoral (NF) se describe originándose desde el plexo lumbar (L2, L3 y L4) y en su recorrido emite ramos destinados a cada una de las porciones del músculo cuádriceps femoral (mCF), los cuales nacen de forma aislada o bien, a partir de troncos comunes. El detalle de la distribución del NF en el mCF, permite disminuir riesgos asociados a diferentes intervenciones quirúrgicas llevadas a cabo en la zona anterior del muslo. Con el propósito describir la distribución del NF en los componentes del mCf. Se utilizaron 15 miembros inferiores formolizados, 10 del lado izquierdo y 5 del lado derecho, de individuos adultos, Brasileños, localizados en los Laboratorios de Anatomía de la Universidade Estadual de Ciências da Saúde de Alagoas (UNCISAL), Maceió, Brasil. El NF se clasificó en cuatro tipos de acuerdo a su ramificación y distribución. El Tipo II se subdividió en 3 subtipos y se presentó en 60 % de las muestras y el tipo III en 20 %. El NF se dividió de medial a lateral hasta en 5 ramos (R1,R2,R3,R4,R5), donde el R1 fue el más medial. El R1 dio origen en promedio a 2,47 ramos secundarios (Rs) y a 2,58 ramos terciarios (Rt), en 13,3 % el R1 no emitió Rs. En 73,3 % inervó a sólo a un componente del mCF; el R2 dio origen en promedio a 3,93 Rs y a 3,58 Rt. En 26,7 % inervó a sólo a un componente del mCF; el R3 dio origen en promedio a 3,33 Rs y a 2,0 Rt. En 80 % inervó a sólo a un componente del mCF. La distribución de R4 y R5 se muestran en el texto. Resultados biométricos de origen, diámetro y longitud de los ramos mencionados son mostrados en tablas. Los datos obtenidos en esta investigación complementan el conocimiento de la anatomía regional, pudiendo ser utilizados por la clínica quirúrgica y para efectuar tratamientos que mejoren trastornos neurológicos que afectan a la región.

The femoral nerve (FN) is described as originating from the lumbar plexus (L2, L3 and L4) and in its course it emits branches destined to each one of the quadriceps femoral muscle (QFm), which are originated in an isolated way or, from common trunks. The detail of the distribution of the FN in the QFm, allows to diminish risks associated with different surgical interventions carried out in the anterior thigh area. With the purpose of describing the distribution of FN in the QFm components. Fifteen formalized lower limbs were used, 10 on the left side and 5 on the right side of adult individuals, Brazilians, located in the Anatomy Laboratories of the State University of Ciências da Saúde de Alagoas (UNCISAL) , Maceió, Brazil. The FN was classified into four types according to its branch and distribution. Type II was subdivided into 3 subtypes and presented in 60 % of the samples and type III in 20 %. The FN was divided from medial to lateral in 5 branches (B1, B2, B3, B4, B5), where B1 was the most medial. The B1 gave rise to an average of 2.47 secondary branches (sB) and to 2.58 tertiary branches (tB), in 13.3 % the B1 did not emit sB. In 73.3 %, only one component of the QFm was invested; B2 gave rise to an average of 3.93 sB and 3.58 tB. In 26.7 %, it invested only one component of the QFm; B3 gave rise to an average of 3.33 sB and 2.0 tB. In 80 %, it invested only one component of the QFm. The distribution of B4 and B5 are shown in the text. Biometric results of origin, diameter and length of the mentioned branches are shown in tables. The data obtained in this research complements the knowledge of the regional anatomy, being able to be used by the surgical clinic and to carry out treatments that improve neurological disorders that affect the region.

Pharyngeal reconstruction by anterolateral thigh flap with vastus lateralis muscle transfer for effective swallowing after total glossolaryngectomy: A case report.

BACKGROUND: We report a novel reconstruction technique that maintained effective swallowing after total glossolaryngectomy (TGL) by restoring pharyngeal constriction using a vascularized vastus lateralis muscle transfer. METHODS: A 65-year-old male with recurrent tongue cancer underwent TGL and anterolateral thigh flap reconstruction with the vastus lateralis muscle. The bilateral cut ends of the remaining posterior pharyngeal wall constrictor muscle were sutured to the transferred vastus lateralis muscle so that the two muscles encircled the reconstructed pharynx. The femoral nerve of the vastus lateralis muscle was coapted to the hypoglossal nerve. RESULTS: Videofluorographic examination showed the contrast bolus flowing smoothly with little assistance from gravity. Laryngoscopic examination showed circumferential constriction of the reconstructed pharynx. The patient could swallow soft food without placing the bolus in his posterior oral cavity or drinking simultaneously. CONCLUSION: The restoration of pharyngeal constriction introduces the possibility of functional swallowing in patients after TGL.

Intramuscular fibre conduction velocity and muscle fascicle length in human vastus lateralis.

Muscle fascicle length and muscle fibre conduction velocity (MFCV) are thought to be important parameters for power performance. It might be expected that faster muscle fibre conduction velocities would compensate for longer fascicle lengths to increase the speed of action potential propagation along the elongated fibres. However, the relationship between muscle fascicle length and MFCV remains unknown. The aim of the present study was to explore the relationship between average vastus lateralis MFCV and average fascicle length. In 17 moderately trained, healthy, male, physical education students (age, 23.4 ± 3.1 years; body height, 178 ± 5.5 cm; body mass, 82.7 ± 6.9 kg; body mass index, 24.6 ± 1.5 kg·m-2) resting MFCV was measured with intramuscular microelectrodes while muscle architecture was evaluated with ultrasonography. Fascicle length was highly correlated with total MFCV (r = 0.923, p = 0.000), maximum MFCV (r = 0.949, p = 0.000), and MFCV of the fastest (r = 0.709, p = 0.001), but not of the slowest fibres (r = 0.131, p = 0.616). No significant correlations were also found between vastus lateralis thickness or fascicle angle with any of MFCV parameters (r = 0.145-0.430; R2 < 0.130; p > 0.05). These data indicate that average MFCV is associated with average fascicle length in vastus lateralis muscle in different individuals. It seems that participants with longer fascicle lengths have also higher MFCVs.

Hypoesthesia after anterior cruciate ligament reconstruction: The relationship between proprioception and vibration perception deficits in individuals greater than one year post-surgery.

BACKGROUND: While surgical reconstruction restores mechanical stability following anterior cruciate ligament (ACL) rupture, many experience early-onset osteoarthritis despite surgery. Neurophysiological changes are hypothesized to contribute to knee osteoarthritis progression. Proprioceptive deficits have been reported following ACL injury/reconstruction; however, vibration perception threshold (VPT) has been less studied. This study explored relationships between pain, VPT, proprioception, function, and strength following ACL-reconstruction. METHODS: Twenty individuals (27 ±â€¯6 years; 10 males) (standard deviation) status-post ACL-reconstruction were compared with a control group. Measurements included VPT, proprioception (threshold to detect passive movement), pain, function (Knee Outcome Survey (KOS)) and isometric quadriceps strength. Group differences were assessed using Mann-Whitney U tests, side-to-side differences with Wilcoxon Signed Rank tests, and associations evaluated using Spearman correlations. RESULTS: The ACL-reconstruction group had minor functional deficits (15 ±â€¯11%) and resting pain (1.8 ±â€¯1.7). Impaired VPT and proprioception (hypoesthesia) were demonstrated on surgical compared to contralateral and control limbs (p ≤ 0.008). Proprioception was significantly different between contralateral and control knees, but not VPT. Surgical knee proprioceptive deficits and VPT deficits were positively correlated (ρ = 0.462, p = 0.047) but not in controls (ρ = -0.042, p = 0.862). Strength was negatively correlated to pain (ρ = -0.589; p = 0.006), but not to KOS scores, proprioception or VPT (p ≥ 0.099). CONCLUSION: Proprioceptive deficits following ACL injury have been ascribed to loss of afferent input from the torn ligament. Alternatively, multi-modality as well as contralateral sensory deficits suggest a spinal/supraspinal source of neurophysiological findings which may predispose to early osteoarthritis. LEVEL OF EVIDENCE: III.

Neurovascular structures in human vastus lateralis muscle and the ideal biopsy site.

A density model of neurovascular structures was generated from 28 human vastus lateralis muscles isolated from embalmed cadavers. The intramuscular portion of arteries, veins, and nerves was dissected, traced on transparencies, and digitized before adjustment to an average muscle shape using Procrustes analysis to generate density distributions for the relative positions of these structures. The course of arteries, veins, and nerves was highly variable between individual muscles. Nevertheless, a zone of lower average neurovascular density was found between the tributaries from the lateral circumflex femoral and the deep femoral arteries. While the area with the lowest density was covered by the iliotibial tract and would therefore not be suitable for biopsies, another low-density area was located in the distal portion of vastus lateralis. This was just anterior to the iliotibial tract, in a zone that has been described as a good needle biopsy site. The reported complication rates of needle biopsies (0.1%-4%) are in the range of expectations when simulated based on this model. It is concluded that the optimal human vastus lateralis biopsy site is in the distal portion of the muscle, between ½ and ¾ of the length from the greater trochanter to the lateral epicondyle, just anterior to the iliotibial band.

Ambulation capacity and functional outcome in patients undergoing neuromuscular electrical stimulation after cardiac valve surgery: A randomised clinical trial.

BACKGROUND: Early mobilization and physical exercise are considered fundamental components in cardiovascular surgery rehabilitation; however, occasionally they are inadequate for inhibiting functional decline. Neuromuscular electrical stimulation (NMES) is a promising tool in cardiovascular rehabilitation; however, to date, no randomized clinical trial has measured the effects of NMES on functional capacity and quality of life in patients who undergo routine cardiac surgery with a short intensive care unit (ICU) stay. Therefore, we aimed to investigate the effects of NMES on walking ability, muscle strength, functional independence, and quality of life in cardiac valve surgery patients in the immediate postoperative period. METHODS: A randomized, parallel, controlled, 2-arm clinical trial with assessor blinding was conducted. Fifty-nine adult patients in the preoperative period after cardiac valve reconstruction and/or replacement were randomly assigned to a control or intervention group. The intervention group underwent NMES in the quadriceps and gastrocnemius, bilaterally, for 60 minutes, for up to 10 sessions. The primary outcome was ambulation ability, assessed through the Six-Minute Walk Test and Walking Speed Test at postoperative day 5 (5PO). Secondary outcomes were muscular strength (assessed through the Medical Research Council scale), functional independence measure (assessed through the Functional Independence Measurement Questionnaire), and quality of life (assessed through the Nottingham Health Profile) at baseline (preoperative) and at postoperative days 3 and 5. RESULTS: The baseline characteristics were similar in both groups, except for body mass index. There was no statistically significant difference, with a small effect size, between both groups regarding the distance walked (95% CI, -64.87 to 65.97) and walking speed (95% CI, -0.55 to 0.57). There was a statistically significant difference in upper-limb muscle strength loss and decline in mobility at postoperative day 3, which had a tendency to recover to initial values at 5PO, in both groups. No significant between-group difference was noted for muscle strength, functional independence, and quality of life. CONCLUSIONS: The use of NMES had no effect on walking ability, strength, quality of life, or functional outcome in the postoperative period for patients that underwent regular valve replacement.

Denervation-activated STAT3-IL-6 signalling in fibro-adipogenic progenitors promotes myofibres atrophy and fibrosis.

Fibro-adipogenic progenitors (FAPs) are typically activated in response to muscle injury, and establish functional interactions with inflammatory and muscle stem cells (MuSCs) to promote muscle repair. We found that denervation causes progressive accumulation of FAPs, without concomitant infiltration of macrophages and MuSC-mediated regeneration. Denervation-activated FAPs exhibited persistent STAT3 activation and secreted elevated levels of IL-6, which promoted muscle atrophy and fibrosis. FAPs with aberrant activation of STAT3-IL-6 signalling were also found in mouse models of spinal cord injury, spinal muscular atrophy, amyotrophic lateral sclerosis (ALS) and in muscles of ALS patients. Inactivation of STAT3-IL-6 signalling in FAPs effectively countered muscle atrophy and fibrosis in mouse models of acute denervation and ALS (SODG93A mice). Activation of pathogenic FAPs following loss of integrity of neuromuscular junctions further illustrates the functional versatility of FAPs in response to homeostatic perturbations and suggests their potential contribution to the pathogenesis of neuromuscular diseases.

Quantification and characterization of grouped type I myofibers in human aging.

INTRODUCTION: Myofiber type grouping is a histological hallmark of age-related motor unit remodeling. Despite the accepted concept that denervation-reinnervation events lead to myofiber type grouping, the completeness of those conversions remains unknown. METHODS: Type I myofiber grouping was assessed in vastus lateralis biopsies from Young (26 ± 4 years; n = 27) and Older (66 ± 4 years; n = 91) adults. Grouped and ungrouped type I myofibers were evaluated for phenotypic differences. RESULTS: Higher type I grouping in Older versus Young was driven by more myofibers per group (i.e., larger group size) (P < 0.05). In Older only, grouped type I myofibers displayed larger cross-sectional area, more myonuclei, lower capillary supply, and more sarco(endo)plasmic reticulum calcium ATPase I (SERCA I) expression (P < 0.05) than ungrouped type I myofibers. DISCUSSION: Grouped type I myofibers retain type II characteristics suggesting that conversion during denervation-reinnervation events is either progressive or incomplete. Muscle Nerve 57: E52-E59, 2018.

Limb-sparing sarcoma reconstruction with functional composite thigh flaps.

INTRODUCTION: Innervated muscle transfer can improve functional outcomes after extensive limb-sparing sarcoma resections. We report our experience using composite thigh flaps for functional reconstruction of large oncologic extremity defects. PATIENTS AND METHODS: Between 2011 and 2014, four limb-sparing oncologic resections (3 lower extremities, 1 upper extremity) underwent immediate functional reconstruction with composite thigh free flaps in three males and one female. The age of the patients ranged from 36 to 73 years. There were 3 soft-tissue sarcomas and one giant cell tumor, all required resection of entire muscle compartments. Flap components included fasciocutaneous tissue with sensory nerve, plicated iliotibial band (ITB), and variable amounts of motorized vastus lateralis (VL). RESULTS: All flaps survived without complications. All patients showed VL motor innervation by six months. Follow-up ranged from 20 to 36 months. Motor strength ranged from 2 to 5 out of 5, active range of motion was 25-92% of normal, and Musculoskeletal Tumor Society (MSTS) Scores were between 22 and 29 out of 30. CONCLUSIONS: Limb-sparing techniques for upper and lower extremity sarcomas continue to evolve. Our experience has validated the composite thigh free flap as an excellent option for one-stage functional reconstruction of large limb defects.

Anterior cruciate ligament reconstruction does not induce further gamma loop abnormalities on the intact side of the quadriceps femoris: A longitudinal study.

This study aimed to investigate the effect of surgery on the gamma loop of the quadriceps on the side with an intact knee in patients with anterior cruciate ligament (ACL) injuries. We compared longitudinally the response of alpha motor neurons to vibration stimulation of the quadriceps on the side with an intact knee before and after ACL reconstruction. To evaluate alpha motor neuron response, we measured the maximal knee extension strength and integrated electromyography of the vastus medialis, vastus lateralis, and rectus femoris. After obtaining pre-vibration data from each subject, vibration stimulation was applied to the infrapatellar tendon, and the same measurements were performed immediately after stimulation. The results of this study showed that the response to prolonged vibration stimulation on the intact side of the quadriceps did not differ pre- and post-surgery. As vibration stimuli normally elicit a decrease in alpha motor neuron activity in normal individuals, abnormal responses to prolonged vibration stimulation of the quadriceps on the side with an intact knee might be observed in patients with ACL injuries. The abnormality of the gamma loop of the quadriceps on the side with an intact knee was probably induced by the rupture. Based on these results, we conclude that surgery does not induce further gamma loop abnormalities on the intact side of the quadriceps.

Knee Extensor Rate of Torque Development Before and After Arthroscopic Partial Meniscectomy, With Analysis of Neuromuscular Mechanisms.

Study Design Descriptive, prospective single-cohort longitudinal study. Background Though rapid torque development is essential in activities of daily living and sports, it hasn't been specifically tested by most physical therapists or incorporated into rehabilitation programs until late in the treatment process. Little evidence is available on quadriceps torque development capacity before and after arthroscopic knee surgery. Objectives To study knee extensor rate of torque development, contributing mechanisms, and associations with strength and patient-reported outcomes before and during the first 6 weeks after arthroscopic partial meniscectomy. Methods Twenty subjects (mean ± SD age, 42.3 ± 13.7 years; body mass index, 26.6 ± 3.1 kg/m2) were tested before surgery, and at 2 and 5 weeks after surgery. Quadriceps muscle volume, strength, activation, rate of torque development, and patient-reported outcomes were evaluated across the study period. Results Significant side-to-side differences in quadriceps strength and voluntary rate of torque development were observed at each time point (P<.05). Changes in muscle activity were associated with changes in rapid torque development capacity. Side-to-side rate of torque development deficits after surgery were associated with lower patient-reported outcomes scores. Conclusion Diminished rapid torque development capacity is common in arthroscopic meniscal debridement patients. This reduced capacity is associated with an inability to quickly recruit and drive the quadriceps muscles (neural mechanisms) and not muscle atrophy or other peripheral factors tested. Patient-reported outcomes are associated with quadriceps rate of torque development, but not strength or muscle size. Rapid torque development warrants greater attention in rehabilitation. J Orthop Sports Phys Ther 2017;47(12):945-956. Epub 9 Oct 2017. doi:10.2519/jospt.2017.7310.

Neuromuscular Electrical Stimulation and Anabolic Signaling in Patients with Stroke.

INTRODUCTION: Stroke results in limited ability to produce voluntary muscle contraction and movement on one side of the body, leading to further muscle wasting and weakness. Neuromuscular electrical stimulation is often used to facilitate involuntary muscle contraction; however, the effect of neuromuscular electrical stimulation on muscle growth and strengthening processes in hemiparetic muscle is not clear. This study examined the skeletal muscle anabolic response of an acute bout of neuromuscular electrical stimulation in individuals with chronic stroke and healthy older adults. METHODS: Eleven individuals (59.8 ± 2.7 years old) were divided into a chronic stroke group (n = 5) and a healthy older adult control group (n = 6). Muscle biopsies were obtained before and after stimulation from the vastus lateralis of the hemiparetic leg for the stroke group and the right leg for the control group. The neuromuscular electrical stimulation protocol consisted of a 60-minute, intermittent stimulation train at 60 Hz. Phosphorylation of mammalian target of rapamycin and ribosomal protein S6 kinase beta-1 were analyzed by Western blot. FINDINGS: An acute bout of neuromuscular electrical stimulation increased phosphorylation of mammalian target of rapamycin (stroke: 56.0%; control: 51.4%; P = .002) and ribosomal protein S6 kinase beta-1 (stroke: 131.2%; control: 156.3%; P = .002) from resting levels to post-neuromuscular electrical stimulation treatment, respectively. Phosphorylated protein content was similar between stroke and control groups at both time points. CONCLUSION: Findings suggest that paretic muscles of patients with chronic stroke may maintain ability to stimulate protein synthesis machinery in response to neuromuscular electrical stimulation.

Dual chimeric innervated vastus lateralis free flap for single stage blink and midface reanimation.

BACKGROUND: The immediate reconstruction of the face in the setting of radical parotidectomy for malignancy represents a particular challenge. We present a novel technique using 2 sections of the vastus lateralis muscle as a chimeric flap in combination with the anterolateral thigh (ALT) fasciocutaneous flap to achieve midface reanimation and eye closure after radical parotidectomy. METHODS: The harvest technique in view of variations in chimeric muscle components, vascular pedicles, and neural coaptations is described herein. RESULTS: On postoperative facial nerve examination, we observed encouraging results in middle-aged patients even in the context of radiotherapy. CONCLUSION: Although reanimation using the chimeric vastus lateralis free flap is yet to be objectively determined in a large series, our experience is that this flap adds the potential of dynamic midface movement and eye closure to our current reconstructive approach with excellent postoperative results in selected cases.