Publications by authors named "Johannes G Dobbe"

Background: Image noise, object repositioning, initial manual image alignment, and stitching of different volumes, i.e. anatomical regions may all affect the stitching error of fused cone-beam computed tomography (CBCT) images.

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Regular blood transfusion is the cornerstone of care for patients with red blood cell (RBC) disorders such as thalassaemia or sickle-cell disease. With repeated transfusion, alloimmunisation often occurs due to incompatibility at the level of minor blood group antigens. We use CRISPR-mediated genome editing of an immortalised human erythroblast cell line (BEL-A) to generate multiple enucleation competent cell lines deficient in individual blood groups.

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Purpose: In reconstructive surgery of scaphoid nonunions with humpback deformity, some surgeons recommend restoration of the normal scaphoid length whereas others overexpand the normal length to ensure carpal realignment and prevent late collapse. To be able to define overexpansion and investigate which levels of overexpansion yield optimal clinical results, a precise method for estimating the original scaphoid length is required. The purpose of this anatomic study was to investigate the precision of estimating normal scaphoid lengths based on intact adjacent bone dimensions, compared with using the contralateral scaphoid length.

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Purpose: In arthroplasty of comminuted radial head fractures, the contralateral radial head diameter can be used as reference for implant selection. However, potential bilateral asymmetry may result in a mismatch of the implant with the native bone. Therefore, our purpose was to evaluate anatomical right-to-left differences of radial head diameters.

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Background: A new type of ankle brace (EXO-L) has recently been introduced. It is designed to limit the motion of most sprains without limiting other motions and to overcome problems such as skin irritation associated with taping or poor fit in the sports shoe.

Purpose: To evaluate the claimed functionality of the new ankle brace in limiting only the motion of combined inversion and plantar flexion.

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Preoperative 3D CT imaging techniques provide displacement analysis of the distal scaphoid fragment in 3D space, using the matched opposite scaphoid as reference. Its accuracy depends on the presence of anatomical bilateral symmetry, which has not been investigated yet using similar techniques. Our purpose was to investigate symmetry by comparing the relative positions of distal and proximal poles between sides.

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Purpose: To determine if 3-dimensional height-to-length (H/L) measurements including coronal plane assessment will improve malalignment detection of scaphoid fractures and to determine if more waist than proximal pole nonunions are malaligned.

Methods: Computed tomography scans of uninjured wrists (n = 74) were used to obtain 3-dimensional models of healthy scaphoids. These models were used to determine 95% normal ranges of the H/L ratio in standard sagittal and coronal planes in an automated fashion.

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Article Synopsis
  • A family with mild dominant spherocytosis displayed partial band 3 deficiency, with the index patient experiencing more severe symptoms compared to other relatives.
  • The study examined the impact of partial pyruvate kinase (PK) deficiency on the clinical manifestation of band 3 deficiency, revealing a novel mutation in the SLC4A1 gene responsible for spherocytosis.
  • Findings indicated that reduced PK activity in the index patient, inherited from a symptomless mother, led to lower ATP levels in red blood cells, resulting in increased osmotic fragility and exacerbating the effects of band 3 deficiency.
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Over the past decade, several anatomical plates have been introduced to improve the result of open reduction and internal fixation of the distal radius. Using 3-dimensional imaging techniques, the authors studied the accuracy and reproducibility of distal radius positioning using anatomical plates.Distal radius fractures and the correction of these fractures were simulated with plastic bone models of radii.

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The authors retrospectively investigated the postoperative position of the distal radius after a corrective osteotomy using 2-dimensional (2-D) and 3-dimensional (3-D) imaging techniques to determine whether malposition correlates with clinical outcome. Twenty-five patients who underwent a corrective osteotomy were available for follow-up. The residual positioning errors of the distal end were determined retrospectively using standard 2-D radiographs and 3-D computed tomography evaluations based on a scan of both forearms, with the contralateral healthy radius serving as reference.

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One of the main determinants of perfusion distribution within an organ is the structure of its vascular network. Past studies were based on angiography or corrosion casting and lacked quantitative three dimensional, 3D, representation. Based on branching rules and other properties derived from such imaging, 3D vascular tree models were generated which were rather useful for generating and testing hypotheses on perfusion distribution in organs.

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The purpose of this study was to develop a rapid and fully automatic method for the assessment of microvascular density and perfusion in sidestream dark field (SDF) images. We modified algorithms previously developed by our group for microvascular density assessment and introduced a new method for microvascular perfusion assessment. To validate the new algorithm for microvascular density assessment, we reanalyzed a selection of SDF video clips (n = 325) from a study in intensive care patients and compared the results to (semi-)manually found microvascular densities.

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The effect of elevated shear stress upon cellular trauma has been studied for many years, but the effect of long-term cyclic stress trauma on hemorheology has never been explored systematically. This study investigated sublytic trauma of red blood cells (RBCs) caused by repeated exposure to shear stress. A suspension of bovine blood was throttled through a capillary tube (inner diameter 1 mm and length 70 mm) connected to a recirculating flow loop.

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Syllectometry is a measuring method that is commonly used to assess red blood cell (RBC) aggregability. In syllectometry, light is incident on a layer of whole blood initially exposed to shear flow. The backscattered light is measured after abruptly stopping the driving mechanism.

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