Rationale: Postoperative pulmonary complications are significant contributors to morbidity in patients who have undergone upper abdominal, thoracic, or cardiac surgery. The pathophysiology of these complications might involve postoperative inspiratory muscle weakness. The nature of postoperative inspiratory muscle weakness is unknown.
Objective: To investigate the effect of surgery on the functioning of the diaphragm, the main muscle of inspiration.
Methods: Serial biopsies from the diaphragm and the latissimus dorsi muscle were obtained from 6 patients during thoracotomy for resection of a tumor in the right lung. Biopsies were taken as soon as the diaphragm had been exposed (t(0)) and again after 2 hours (t(2)). The contractile performance of demembranated muscle fibers, as well as fiber morphology and markers for proteolysis, was determined.
Results: In all patients, the force-generating capacity of diaphragm muscle fibers at t(2) was significantly reduced (~35%) compared with that at t(0), with a more pronounced force loss in type 2 fibers compared with type 1 fibers. Diaphragm weakness was not part of a generalized muscle weakness as contractile performance of latissimus dorsi fibers was preserved at t(2). Diaphragm fiber size and myofibrillar structure were not different at t(2) compared with t0, but myosin heavy chain type 2 was significantly reduced at t(2) and MuRF-1 mRNA and protein levels were elevated at t(2).
Conclusions: Only 2 hours of thoracic surgery causes marked, and selective, diaphragm muscle fiber weakness.
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http://dx.doi.org/10.1097/SLA.0b013e318232e75b | DOI Listing |
J Orthop Res
December 2024
Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
Hip abductors are essential for hip function. To understand abduction weakness, it is important to know which muscles contribute to abduction force. Our aim was to investigate the effects of an experimentally induced weakness of the different muscles (tensor fasciae latae [TFL], gluteus medius and minimus (Gmed/min), gluteus maximus [Gmax]) on the abduction force.
View Article and Find Full Text PDFAm J Case Rep
December 2024
Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden.
BACKGROUND Limb-girdle muscular dystrophy recessive 1 (LGMDR1) is an autosomal recessive degenerative muscle disorder characterized by progressive muscular weakness caused by pathogenic variants in the CAPN3 gene. Desmoplastic small round cell tumors (DSRCT) are ultra-rare and aggressive soft tissue sarcomas usually in the abdominal cavity, molecularly characterized by the presence of a EWSR1::WT1 fusion transcript. Mouse models of muscular dystrophy, including LGMDR1, present an increased risk of soft tissue sarcomas.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Critical Care Medicine, Heping Hospital Affiliated to Changzhi Medical College, 110 South Yan'an Road, Luzhou District, Changzhi City, 046012, China.
Mechanical ventilation contributes to diaphragm atrophy and muscle weakness, which is referred to as ventilator-induced diaphragmatic dysfunction (VIDD). The pathogenesis of VIDD has not been fully understood until recently. The aim of this study was to investigate the effects of 24 h of mechanical ventilation on fibro-adipogenic progenitor (FAP) proliferation, endothelial-mesenchymal transition (EndMT), and immune cell infiltration driving diaphragm fibrosis in a rabbit model.
View Article and Find Full Text PDFClin Biomech (Bristol)
December 2024
Amsterdam UMC location University of Amsterdam, Rehabilitation Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Movement Sciences, Rehabilitation and Development, Amsterdam, the Netherlands. Electronic address:
Background: Clinical decisions regarding ankle-foot-orthosis stiffness in people with calf muscle weakness are based on immediate evaluations, not taking gait adaptation into account. This study examined adaptation of step length, walking speed and energy cost of walking in the 3-months post-provision and whether individuals with higher gait variability adapt more compared to individuals with lower gait variability.
Methods: We conducted a post-hoc analysis in eighteen stiffness-optimized ankle-foot-orthosis users with bilateral calf muscle weakness.
Am J Otolaryngol
December 2024
Department of Otolaryngology - Head & Neck Surgery, University of Michigan, Ann Arbor, MI, USA. Electronic address:
Purpose: We examined operative efficiency, rate of facial nerve paresis, and post-operative outcomes in patients undergoing retrograde (RGD) vs anterograde dissection (AGD) of the facial nerve controlling for tumor location.
Methods: Single-institution, retrospective analysis of patients with benign parotid tumors undergoing superficial parotidectomy with facial nerve dissection over a six-year period. Operative and pathology reports were reviewed to classify tumor size, location in relation to facial nerve branches, and technique for facial nerve dissection.
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