The influence of visual information on multi-muscle control during quiet stance: a spectral analysis approach

Standing upright requires the coordination of neural drives to a large set of muscles involved in controlling human bipedal stance (i.e., postural muscles). The coordination may deteriorate in situations where standing is performed under more challenging circumstances, such as standing on a smaller base of support or not having adequate visual information. The present study investigates the role of common neural inputs in the organization of multi-muscle synergies and the effects of visual input disruption to this mechanism of control. We analyzed the strength and distribution of correlated neural inputs (measured by intermuscular coherence) to six postural muscles previously recognized as components of synergistic groups involved in the maintenance of the body's vertical positioning. Two experimental conditions were studied: quiet bipedal stance performed with opened eyes (OEs) and closed eyes (CEs). Nine participants stood quietly for 30 s while the activity of the soleus, biceps femoris, lumbar erector spinae, tibialis anterior, rectus femoris, and rectus abdominis muscles were recorded using surface electrodes. Intermuscular (EMG-EMG) coherence was estimated for 12 muscle pairs formed by these muscles, including pairs formed solely by either posterior, anterior, or mixed (one posterior and one anterior) muscles. Intermuscular coherence was only found to be significant for muscle pairs formed solely by either posterior or anterior muscles, and no significant coherence was found for mixed muscle pairs. Significant intermuscular coherence was only found within a distinct frequency interval bounded between 1 and 10 Hz when visual input was available (OEs trials). The strength of correlated neural inputs was similar across muscle pairs located in different joints but executing a similar function (pushing body either backward or forward) suggesting that synergistic postural groups are likely formed based on their functional role instead of their anatomical location. Absence of visual information caused a significant decrease in intermuscular coherence. These findings are consistent with the hypothesis that correlated neural inputs are a mechanism used by the CNS to assemble synergistic muscle groups. Further, this mechanism is affected by interruption of visual input

Minimally Invasive Heart-Port Assisted Technique as Standard First Choice Approach for Left Ventricle Endoplasty: A Ten-Year Single-Center Experience

Abstract BACKGROUND: Although the port-access technique has been shown to be an effective and safe approach for cardiac surgery procedures it has never become routine practice, and it is still limited to few and selected centers. Furthermore, such technique has rarely been applied to treat left ventricle disease. In 1999 we introduced left ventricle aneurysm repair through a left minithoracotomy using the port-access technique. Here we present the results in terms of early and medium-term follow-up using such technique as a routine first choice approach for left ventricle endoplasty. METHODS: From 1999 to date, out of 38 patients undergoing left ventricle endoplasty (+/-associate procedures), mini-left thoracotomy and port-access techniques have been used in 32 patients (84%). All patients underwent endoventricular patch-repair with ventricular reshaping and associated procedures were performed in 8 patients. RESULTS: All patients survived the operation and were discharged from the hospital (30 days mortality 0%). Two patients (6.2%) experienced prolonged mechanical ventilations and 3 patients (9.3%) prolonged intensive care unit stay. Mean follow-up was 40+/-34 months (range, 2 to 105). One patient died during follow-up (cumulative mortality 3.3%). Follow-up revealed an improvement of hemodynamic performances (left ventricular ejection fraction 0.44+/-0.09 compared with 0.34+/-0.09 preoperatively, p=0.004) and improved clinical conditions (New York Heart Association class 1.4+/-0.5 compared with 2.3+/-1 preoperatively, p=0.003). CONCLUSIONS: The port-access technique can be safely applied to perform left ventricle endoplasty through a left minithoracotomy. Such approach allows optimal surgical view and therefore optimal surgical correction. Based on our satisfactory experience we support left minithoracotomy as a valuable alternative approach for left ventricle endoplasty in view of an extended use of minimally invasive techniques

The axillary artery as an alternative site of cannulation for redo port access-assisted minimally invasive mitral valve surgery: early report of 2 cases

Abstract: The minimally invasive Heartport (HP)-assisted technique has become first choice option for mitral valve surgery in many centres. The pool of patients potentially treated using HP techniques, however, is still limited by the presence of peripheral vessel disease, expecially in the elderly population. Alternative approaches to using the HP technique safely in such a subset of patients, therefore, should be evaluated. Here, we present our preliminary experience using the axillary artery as an alternative site of cannulation for HP-assisted redo mitral valve surgery in patients with concomitant peripheral vessel disease