title: Anatomical sector analysis of load-bearing tibial bone structure during 90-day bed rest and 1-year recovery.
abstract: The aim of this study was to investigate whether the bone response to long bed rest-related immobility and during subsequent recovery differed at anatomically different sectors of tibial epiphysis and diaphysis. For this study, peripheral quantitative tomographic (pQCT) scans obtained from a previous 90-day 'Long Term Bed Rest' intervention were preprocessed with a new method based on statistical approach and re-analysed sector-wise. The pQCT was performed on 25 young healthy males twice before the bed rest, after the bed rest and after 1-year follow-up. All men underwent a strict bed rest intervention, and in addition, seven of them received pamidronate treatment and nine did flywheel exercises as countermeasures against disuse-related bone loss. Clearly, 3-9% sector-specific losses in trabecular density were observed at the tibial epiphysis on average. Similarly, cortical density decreased in a sector-specific way being the largest at the anterior sector of tibial diaphysis. During recovery, the bed rest-induced bone losses were practically restored and no consistent sector-specific modulation was observed in any subgroup. It is concluded that the sector-specific analysis of bone cross-sections has potential to reveal skeletal responses to various interventions that cannot be inferred from the average analysis of the whole bone cross-section. This approach is considered also useful for evaluating the bone responses from the biomechanical point of view.
authors.affiliation: Department of Biomedical Engineering, Tampere University of Technology, Tampere, Finland. tomas.cervinka@tut.fi
authors.forename: Tomas
authors.initials: T
authors.lastname: Cervinka
authors.forename: Jörn
authors.initials: J
authors.lastname: Rittweger
authors.forename: Jari
authors.initials: J
authors.lastname: Hyttinen
authors.forename: Dieter
authors.initials: D
authors.lastname: Felsenberg
authors.forename: Harri
authors.initials: H
authors.lastname: Sievänen
mesh_terms: D000328:Adult; D001510:Bed Rest; D015519:Bone Density / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging* / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult