Effects of ankle–foot braces on medial gastrocnemius morphometrics and gait in children with cerebral palsy

PurposeIn children with cerebral palsy (CP), braces are used to counteract progressive joint and muscle contracture and improve function. We examined the effects of positional ankle–foot braces on contracture of the medial gastrocnemius (MG) and gait in children with CP while referencing to typically developing children.MethodsSeventeen independently ambulant children with CP and calf muscle contracture (age 10.4 ± 3.0y) and 17 untreated typically developing peers (age 9.5 ± 2.6y) participated. Children with CP were analysed before and 16 ± 4 weeks after ankle–foot bracing. MG muscle belly length and thickness, tendon and fascicle length, as well as their extensibility were captured by 2D ultrasound and 3D motion capturing during passive, manually applied stretches. In addition, 3D gait analysis was conducted.ResultsPrior to bracing, the MG muscle–tendon unit in children with CP was 22 % less extensible. At matched amounts of muscle–tendon unit stretch, the muscle belly and fascicles in CP were 7 % and 14 % shorter while the tendon was 11 % longer. Spastic fascicles displayed 32 % less extensibility than controls. Brace wear increased passive dorsiflexion primarily with the knees flexed. During gait, children walked faster and foot lift in swing improved. MG muscle belly and tendon length showed little change, but fascicles further shortened (−11 %) and muscle thickness (−8 %) decreased.ConclusionsUse of ankle–foot braces improves function but may lead to a loss of sarcomeres in series, which could explain the shortened fascicles. To potentially induce gastrocnemius muscle growth, braces may also need to extend the knee or complementary training may be necessary to offset the immobilizing effects of braces.     

Inferior mesenteric arteriovenous fistula: Case report and world-literature review

Arteriovenous fistulas between the inferior mesenteric artery and vein are rare, with only 26 primary and secondary cases described in the literature. Secondary fistulas occur following operations of the left hemicolon and manifest as abdominal pain, abdominal mass, gastrointestinal bleeding, colonic ischemia and portal hypertension. Symptom intensities are flow-dependent, and can range from minimal symptoms to severe heart failure due to left to right shunt. Diagnosis is usually established by radiological or intraoperative examination. Treatment options include embolization and/or surgical resection. Therapeutic decisions should be adapted to the unique characteristics of the fistula on an individual basis. A new case of a primary arteriovenous fistula is described and discussed along with a complete review of the literature. The patient in this report presented with signs and symptoms of colonic ischemia without portal hypertension. The optimal treatment for this patient required a combination of embolization and surgical operation. The characteristics of these rare inferior mesenteric arteriovenous fistulas are examined and some considerations concerning diagnostic and therapeutic strategies that should be followed are presented.     

Differences between measured and resultant joint moments during voluntary and artificially elicited isometric knee extension contractions

OBJECTIVE: Examine two hypotheses: (a) during isometric knee extension contractions the moment measured at the dynamometer is different from the resultant moment in the same plane around the knee joint and (b) during isometric contractions, at the same given resultant moment the knee angle while loading is different from the knee angle while unloading. DESIGN: Comparative study in which the geometrical and the kinetic differences between joint and dynamometer were determined. BACKGROUND: It is usually assumed that the moment measured by the dynamometer is equivalent to the resultant joint moment. The non-rigidity of the dynamometer-leg system can influence the equivalence of these two moments. METHOD: Twenty seven subjects performed isometric maximal knee extension contractions and contractions induced by electrostimulation on a dynamometer. The kinematics of the leg were recorded using 8 cameras (120 Hz). RESULTS: The resultant moment at the knee joint and the moment measured by the dynamometer are different. During a knee extension effort the knee angle changes significantly. At identical resultant knee joint moments the knee angles are different when comparing the loading and the unloading phases. CONCLUSIONS: The differences between the measured and the resultant joint moments might influence the estimation of parameters as: muscle forces, moment-angle relationship and strain and hysteresis of tendons and aponeuroses. RELEVANCE: Torque dynamometers have been often used to estimate muscle forces, to examine neuromuscular processes and to determine the mechanical properties of tendons and aponeuroses.     

Exercise-induced changes in triceps surae tendon stiffness and muscle strength affect running economy in humans

The purpose of the present study was to investigate whether increased tendon-aponeurosis stiffness and contractile strength of the triceps surae (TS) muscle-tendon units induced by resistance training would affect running economy. Therefore, an exercise group (EG, n = 13) performed a 14-week exercise program, while the control group (CG, n = 13) did not change their training. Maximum isometric voluntary contractile strength and TS tendon-aponeurosis stiffness, running kinematics and fascicle length of the gastrocnemius medialis (GM) muscle during running were analyzed. Furthermore, running economy was determined by measuring the rate of oxygen consumption at two running velocities (3.0, 3.5 ms^?1). The intervention resulted in a ～7 % increase in maximum plantarflexion muscle strength and a ～16 % increase in TS tendon-aponeurosis stiffness. The EG showed a significant ～4 % reduction in the rate of oxygen consumption and energy cost, indicating a significant increase in running economy, while the CG showed no changes. Neither kinematics nor fascicle length and elongation of the series-elastic element (SEE) during running were affected by the intervention. The unaffected SEE elongation of the GM during the stance phase of running, in spite of a higher tendon-aponeurosis stiffness, is indicative of greater energy storage and return and a redistribution of muscular output within the lower extremities while running after the intervention, which might explain the improved running economy.     

Age-related degeneration in leg-extensor muscle–tendon units decreases recovery performance after a forward fall: compensation with running experience

The goals of this study were to investigate whether the lower muscle-tendon units (MTUs) capacities in older affect their ability to recover balance with a single-step after a fall, and to examine whether running experience enhances and protects this motor skill in young and old adults. The investigation was conducted on 30 older and 19 younger divided into two subgroups: runners versus non-active. In previous studies we documented that the older had lower leg extensor muscle strength and tendon stiffness while running had no effect on MTUs capacities. The current study examined recovery mechanics of the same individuals after an induced forward fall. Younger were better able to recover balance with a single-step compared to older (P < 0.001); this ability was associated with a more effective body configuration at touchdown (more posterior COM position relative to the recovery foot, P <0.001). MTUs capacities classified 88.6% of the subjects into single- or multiple-steppers. Runners showed a superior ability to recover balance with a single-step (P < 0.001) compared to non-active subjects due to a more effective mechanical response during the stance phase (greater knee joint flexion, P <0.05). We concluded that the age-related degeneration of the MTUs significantly diminished the older adults' ability to restore balance with a single-step. Running seems to enhance and protect this motor skill. We suggested that runners, due to their running experience, could update the internal representation of mechanisms responsible for the control of dynamic stability during a forward fall and, thus, were able to restore balance more often with a single-step compared to the non-active subjects.     

A wide number of trials is required to achieve acceptable reliability for measurement patellar tendon elongation in vivo

The purpose of the current study was to examine the reproducibility of patellar tendon elongation measurements using brightness-mode ultrasonography (BMU) during isometric knee extension contractions. We hypothesized that the measurement of the patellar tendon elongation during only one maximal voluntary isometric knee extension contractions would not provide reliable results and that a wide number of trials is required to achieve acceptable reliability. Ten participants (eight male and two female) performed 10 isometric knee extension contractions on two separate days (5 trials on each day). Using a modified knee brace, the ultrasound probe was firmly adjusted in the sagittal plane overlying the patellar tendon. The registered ultrasound images were analyzed by three different but equally trained observers. The reproducibility was examined by the calculation of the within-day, between-day and overall coefficient of multiple correlations (wCMC, bCMC and oCMC). The Spearman-Brown prophecy formula was use to estimate the required trials to achieve the desired reliability. The wCMC, bCMC and oCMC were in average 0.824, 0.798 and 0.770, respectively, suggesting a rather moderate reproducibility of patellar tendon elongation measurements. For a high reliability (≥0.95) of tendon elongation measurements 5-6 trials are required. Finally, the results revealed an independence of the measurements from days and observers.     

Primary Ewing's sarcoma of the kidney with caval involvement: a case report

Ewing sarcoma, also referred to as primitive neuroectodermal tumor (PNET), is a malignancy, histologically characterized by Homer-Wright rosettes and small round cells, that presents most commonly in bone or soft tissue in the pediatric and adolescent populations. We report the case of a patient that presents with intermittent gross hematuria, abdominal mass and elevated blood pressure. After surgical excision of the renal mass, the rare finding of a primary renal Ewing's sarcoma was discovered. After surgery the patient was additionally treated with chemotherapy. After presenting this case, we briefly discuss the unique case of isolated renal Ewing's sarcoma, including incidence and treatment.     

Hybrid Laparoscopic and Endoscopic Partial Gastrectomy for Ulcerated GIST: Surgical Technique with Video

Introduction

Gastrointestinal stromal tumors of the gastric cardia pose several technical difficulties to their resection because they are difficult to access, and they must be removed respecting oncological principles, and due to their proximity to the gastroesophageal junction, excessive removal of gastric tissue may cause deformation with gastric dysfunction, or gastroesophageal reflux.

Method

Hybrid laparoscopic endoscopic partial gastrectomy is a technique that avoids these problems making use of three principles. First the tumor is pinpointed, marked, and resected under combined laparoscopic and endoscopic control to assure that it is completely resected without compromising the structure of the gastroesophageal junction. Second, a dissection of the abdominal esophagus is performed as during a Nissen fundoplication in order to increase the distance between the tumor and the gastroesophageal junction. Third the lesser curvature of the stomach is dissected, and the terminal branches of the left gastric vessels are controlled from the gastric incisura to the gastroesophageal junction exposing the lesser curvature and the posterior wall of the stomach. The tumor is resected under endoscopic control, tangentially with an endoscopic stapler applied parallel to the lesser curvature similarly to a sleeve partial gastrectomy.

Results

No abdominal drain is used, and a nasogastric tube is left in place for the first 24 h after surgery. The patient receives fluid diet on the first postoperative day, is discharged on the second postoperative day, and is followed up in the outpatient department for a week.

Conclusion

In this technical paper, the procedure is described in detail and demonstrated with video.

     

Strain and elongation of the vastus lateralis aponeurosis and tendon in vivo during maximal isometric contraction

The strain and elongation of the vastus lateralis (VL) tendon, tendon plus aponeurosis, and aponeurosis were examined during maximal voluntary contractions on a Biodex-dynamometer (knee angle 115°, hip angle 140°) in 12 sprinters. Following a warm-up phase, the subjects were instructed to perform a gradual maximal knee extension and hold it for about 3 s. The kinematics of the leg were recorded using a Vicon 512 system with eight cameras operating at 120 Hz. Ultrasonography images were taken simultaneously from the VL myotendinous junction and the mid lateral part of the VL muscle belly. During the maximal isometric knee extensions, the knee joint rotated (13.6±5.9°), leading to an overestimation of the elongation of the tendinous tissues. After correcting for this, the maximal elongation of the VL tendon examined at the myotendinous junction was lower (P<0.05) than the maximal elongation of the VL tendon plus aponeurosis examined at the muscle belly (15 vs. 27 mm, respectively). The maximal estimated strains of the tendon, tendon plus aponeurosis, and aponeurosis showed no statistical differences (8±2%, 8±1%, and 7±2%, respectively, P>0.05). It is concluded that the strains of the human VL tendon, VL tendon plus aponeurosis, and VL aponeurosis, as estimated in vivo by two dimensional ultrasound during maximal isometric contractions, do not differ from each other. The displacement measured at a cross point in the VL muscle belly is significantly greater than that measured at the VL myotendinous junction.