Compression-induced deep tissue injury examined with magnetic resonance imaging and histology

• Published in: Journal of applied physiology (1985) Vol. 100; no. 6; pp. 1946 - 1954
• Main Authors: Stekelenburg, A, Oomens, C. W. J, Strijkers, G. J, Nicolay, K, Bader, D. L
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.06.2006; American Physiological Society
• Subjects: Animals; Biological and medical sciences; Female; Fundamental and applied biological sciences. Psychology; Inflammation - pathology; Injuries; Magnetic Resonance Imaging; Muscle Fibers, Skeletal - pathology; Necrosis - pathology; NMR; Nuclear magnetic resonance; Pressure Ulcer - pathology; Pressure ulcers; Rats; Rats, Inbred BN; Weight-Bearing; Animal model; Tissue; Skin disease; Vertebrata; Compression; Mammalia; deep pressure ulcers: decubitus; Histology; Lesion; Pressure sore; Nuclear magnetic resonance imaging
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00889.2005

1 Department of Materials Technology; 2 Biomedical NMR, Eindhoven University of Technology, Eindhoven, The Netherlands; and 3 Department of Engineering and IRC in Biomedical Materials, Queen Mary, University of London, London, United Kingdom Submitted 22 July 2005 ; accepted in final form 14 February 2006 The underlying mechanisms leading to deep tissue injury after sustained compressive loading are not well understood. It is hypothesized that initial damage to muscle fibers is induced mechanically by local excessive deformation. Therefore, in this study, an animal model was used to study early damage after compressive loading to elucidate on the damage mechanisms leading to deep pressure ulcers. The tibialis anterior of Brown-Norway rats was loaded for 2 h by means of an indenter. Experiments were performed in a magnetic resonance (MR)-compatible loading device. Muscle tissue was evaluated with transverse relaxation time (T2)-weighted MRI both during loading and up to 20 h after load removal. In addition, a detailed examination of the histopathology was performed at several time points (1, 4, and 20 h) after unloading. Results demonstrated that, immediately after unloading, T2-weighted MR images showed localized areas with increased signal intensity. Histological examination at 1 and 4 h after unloading showed large necrotic regions with complete disorganization of the internal structure of the muscle fibers. Hypercontraction zones were found bilateral to the necrotic zone. Twenty hours after unloading, an extensive inflammatory response was observed. The proposed relevance of large deformation was demonstrated by the location of damage indicated by T2-weighted MRI and the histological appearance of the compressed tissues. Differences in damage development distal and proximal to the indenter position suggested a contribution of perfusion status in the measured tissue changes that, however, appeared be to reversible. deep pressure ulcers; decubitus; animal model Address for reprint requests and other correspondence: A. Stekelenburg, Eindhoven Univ. of Technology, Dept. of Biomedical Engineering, PO Box 513, Den Dolech 2, 5600 MB Eindhoven, The Netherlands (e-mail: A.Stekelenburg{at}tue.nl )