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Dive into the research topics where Harald Marcel Bonel is active.

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Featured researches published by Harald Marcel Bonel.


Swiss Medical Weekly | 2011

Rapid induction of remission in large vessel vasculitis by IL-6 blockade. A case series.

Michael Seitz; Stephan Reichenbach; Harald Marcel Bonel; Sabine Adler; Felix Wermelinger; Peter M. Villiger

OBJECTIVE To evaluate the effect of IL-6 blockade using tocilizumab in inducing remission of arterial large vessel vasculitides (LVV). METHODS Five consecutive patients with giant-cell arteritis (GCA) and two with Takayasus arteritis (TA) were treated by tocilizumab infusions (8 mg/kg). Tocilizumab was given every other week for the first month and once monthly thereafter. Clinical symptoms of disease activity, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level and glucocorticoid (GC) dosage necessary to maintain remission were prospectively assessed. MR angiography was performed to monitor local inflammation. RESULTS Of the seven patients three were newly diagnosed and four showed GC resistance, i.e. GC could not be lowered to less than 7.5 mg/day. The mean follow-up time was 4.3 months (range 3-7 months). All patients achieved a rapid and complete clinical response and normalisation of the acute phase proteins. Remarkably, prednisone dosage could be reduced within 12 weeks to a mean of 2.5 mg/day (range 0-10 mg/day). No relapse and no drug-related side effects were noted. CONCLUSION Collectively the data suggest that IL-6 blockade using tocilizumab qualifies as a therapeutic option to induce rapid remission in large vessel vasculitides.


Arthritis & Rheumatism | 2011

Association between cam‐type deformities and magnetic resonance imaging–detected structural hip damage: A cross‐sectional study in young men

Stephan Reichenbach; Michael Leunig; Stefan Werlen; Eveline Nüesch; Christian W. A. Pfirrmann; Harald Marcel Bonel; Alex Odermatt; Willy Hofstetter; Reinhold Ganz; Peter Jüni

OBJECTIVE Femoroacetabular impingement may be a risk factor for hip osteoarthritis in men. An underlying hip deformity of the cam type is common in asymptomatic men with nondysplastic hips. This study was undertaken to examine whether hip deformities of the cam type are associated with signs of hip abnormality, including labral lesions and articular cartilage damage, detectable on magnetic resonance imaging (MRI). METHODS In this cross-sectional, population-based study in asymptomatic young men, 1,080 subjects underwent clinical examination and completed a self-report questionnaire. Of these subjects, 244 asymptomatic men with a mean age of 19.9 years underwent MRI. All MRIs were read for cam-type deformities, labral lesions, cartilage thickness, and impingement pits. The relationship between cam-type deformities and signs of joint damage were examined using logistic regression models adjusted for age and body mass index. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were determined. RESULTS Sixty-seven definite cam-type deformities were detected. These deformities were associated with labral lesions (adjusted OR 2.77 [95% CI 1.31, 5.87]), impingement pits (adjusted OR 2.9 [95% CI 1.43, 5.93]), and labral deformities (adjusted OR 2.45 [95% CI 1.06, 5.66]). The adjusted mean difference in combined anterosuperior femoral and acetabular cartilage thickness was -0.19 mm (95% CI -0.41, 0.02) lower in those with cam-type deformities compared to those without. CONCLUSION Our findings indicate that the presence of a cam-type deformity is associated with MRI-detected hip damage in asymptomatic young men.


Swiss Medical Weekly | 2011

Rapid induction of remission in large vessel vasculitis by IL-6 blockade

Michael Seitz; Stephan Reichenbach; Harald Marcel Bonel; Sabine Adler; Felix Wermelinger; Peter M. Villiger

OBJECTIVE To evaluate the effect of IL-6 blockade using tocilizumab in inducing remission of arterial large vessel vasculitides (LVV). METHODS Five consecutive patients with giant-cell arteritis (GCA) and two with Takayasus arteritis (TA) were treated by tocilizumab infusions (8 mg/kg). Tocilizumab was given every other week for the first month and once monthly thereafter. Clinical symptoms of disease activity, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level and glucocorticoid (GC) dosage necessary to maintain remission were prospectively assessed. MR angiography was performed to monitor local inflammation. RESULTS Of the seven patients three were newly diagnosed and four showed GC resistance, i.e. GC could not be lowered to less than 7.5 mg/day. The mean follow-up time was 4.3 months (range 3-7 months). All patients achieved a rapid and complete clinical response and normalisation of the acute phase proteins. Remarkably, prednisone dosage could be reduced within 12 weeks to a mean of 2.5 mg/day (range 0-10 mg/day). No relapse and no drug-related side effects were noted. CONCLUSION Collectively the data suggest that IL-6 blockade using tocilizumab qualifies as a therapeutic option to induce rapid remission in large vessel vasculitides.


Arthritis Care and Research | 2009

Measuring finger joint cartilage by ultrasound as a promising alternative to conventional radiograph imaging

Burkhard Möller; Harald Marcel Bonel; Marianne Rotzetter; Peter M. Villiger; Hans-Rudolf Ziswiler

OBJECTIVE To evaluate the reliability and validity of a novel ultrasound (US) imaging method to measure metacarpophalangeal (MCP) and proximal interphalangeal (PIP) finger joint cartilage. METHODS We examined 48 patients with rheumatoid arthritis (RA), 18 patients with osteoarthritis (OA), 24 patients with unclassified arthritis of the finger joints, and 34 healthy volunteers. The proximal cartilage layer of MCP and PIP joints for fingers 2-5 was bilaterally visualized from a posterior view, with joints in approximately 90 degrees flexion. Cartilage thickness was measured with integrated tools on static images. External validity was assessed by measuring radiologic joint space width (JSW) and a numeric joint space narrowing (JSN) score in patients with RA. RESULTS Precise measurement was possible for 97.5% of MCP and 94.2% of PIP joints. Intraclass correlation coefficients for bilateral total joint US scores were 0.844 (95% confidence interval [95% CI] 0.648-0.935) for interobserver comparisons and 0.928 (95% CI 0.826-0.971) for intraobserver comparisons (using different US devices). The US score correlated with JSN for both hands (adjusted R(2) = 0.513, P < 0.001) and JSW of the same finger joints (adjusted R(2) = 0.635, P < 0.001). Reduced cartilage shown by US allowed discrimination of early symptomatic OA versus early RA and healthy joints. In patients with RA, US scores correlated with duration of treatment-resistant, progressive RA. CONCLUSION The US method of direct visualization and quantification of cartilage in MCP and PIP joints is objective, reliable, valid, and can be useful for diagnostic purposes in patients with arthritis.


Radiology | 2010

Diffusion-weighted MR Imaging of the Placenta in Fetuses with Placental Insufficiency

Harald Marcel Bonel; Bernhard Stolz; Lars Diedrichsen; Kathrin Frei; Bettina Saar; B. Tutschek; Luigi Raio; Daniel Surbek; Sudesh Srivastav; Mathias Nelle; Johannes Slotboom; Roland Wiest

PURPOSE To evaluate diffusion-weighted magnetic resonance (MR) imaging of the human placenta in fetuses with and fetuses without intrauterine growth restriction (IUGR) who were suspected of having placental insufficiency. MATERIALS AND METHODS The study was approved by the local ethics committee, and written informed consent was obtained. The authors retrospectively evaluated 1.5-T fetal MR images from 102 singleton pregnancies (mean gestation ± standard deviation, 29 weeks ± 5; range, 21-41 weeks). Morphologic and diffusion-weighted MR imaging were performed. A region of interest analysis of the apparent diffusion coefficient (ADC) of the placenta was independently performed by two observers who were blinded to clinical data and outcome. Placental insufficiency was diagnosed if flattening of the growth curve was detected at obstetric ultrasonography (US), if the birth weight was in the 10th percentile or less, or if fetal weight estimated with US was below the 10th percentile. Abnormal findings at Doppler US of the umbilical artery and histopathologic examination of specimens from the placenta were recorded. The ADCs in fetuses with placental insufficiency were compared with those in fetuses of the same gestational age without placental insufficiency and tested for normal distribution. The t tests and Pearson correlation coefficients were used to compare these results at 5% levels of significance. RESULTS Thirty-three of the 102 pregnancies were ultimately categorized as having an insufficient placenta. MR imaging depicted morphologic changes (eg, infarction or bleeding) in 27 fetuses. Placental dysfunction was suspected in 33 fetuses at diffusion-weighted imaging (mean ADC, 146.4 sec/mm(2) ± 10.63 for fetuses with placental insufficiency vs 177.1 sec/mm(2) ± 18.90 for fetuses without placental insufficiency; P < .01, with one false-positive case). The use of diffusion-weighted imaging in addition to US increased sensitivity for the detection of placental insufficiency from 73% to 100%, increased accuracy from 91% to 99%, and preserved specificity at 99%. CONCLUSION Placental dysfunction associated with growth restriction is associated with restricted diffusion and reduced ADC. A decreased ADC used as an early marker of placental damage might be indicative of pregnancy complications such as IUGR. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10092283/-/DC1.


Journal of Orthopaedic Trauma | 2009

Reliability of radiologic assessment of the fracture anatomy at the posterior tibial plafond in malleolar fractures

Lorenz Büchler; Moritz Tannast; Harald Marcel Bonel; Martin Weber

Objectives: The aim of this study was to assess the ability to extract surgically relevant information from plain radiographs in trimalleolar fractures and to compare this with the information gathered from computed tomography (CT). Design: Retrospective analysis of consecutive patients. Setting: Level 1 trauma center. Patients: Retrospective analysis of the records of 22 patients with trimalleolar fractures treated at our institution between 1996 and 2006. Inclusion criteria were a complete radiographic documentation including plain anteroposterior and lateral radiographs and a preoperative CT scan of the ankle joint. Intervention: The radiographs of the included patients were evaluated twice within 3 months by 8 experienced orthopaedic trauma surgeons. The following criteria were analyzed: the presence or absence of a fracture in the posteromedial corner of the tibial plafond, loose posterior osteochondral fragments, impaction of posterior osteochondral fragments on the anteroposterior and the lateral radiographs, and size of the posterolateral fragment as percentage of the articular surface in the capital diameter of the tibial plafond. The results were compared with the CT scans. Results: All parameters showed a poor to fair reproducibility, reliability, and accuracy except the size of the posterior fragment, where good correlations were achieved. Conclusions: Only the extent of the posterior fragment can be measured reliably, reproducibly, and accurately on plain radiographs. Comminution and impaction of the posterior fracture are underestimated by far. Surgically relevant information is missed, which can lead to intraoperative inability to properly reduce the fracture. Preoperative CT evaluation is recommended in all patients with trimalleolar fractures, independent of the size of the posterior fragment.


Journal of Computer Assisted Tomography | 2004

Local staging of rectal cancer: assessment with double-contrast multislice computed tomography and transrectal ultrasound.

Christiane Kulinna; Juergen Scheidler; Tim Strauss; Harald Marcel Bonel; Karin A. Herrmann; Daniela Aust; Maximilian F. Reiser

Objective: The aim of this study was to evaluate the accuracy of multislice computed tomography (MSCT) with double-contrast technique and transrectal ultrasound (TRUS) in staging of rectal carcinoma compared with histopathological confirmation. Methods: In a prospective study of 92 patients with rectal carcinoma, preoperative MSCT with negative rectal contrast (methylcellulose) and intravenous contrast was performed. Reconstructions in 3 planes were analyzed in a cine mode in picture archiving and communication (PAC) system. Analysis of rectal wall infiltration was performed preoperatively according to a modified tumor, nodes, metastases (TNM)-classfication system (≤T2/T3/T4, N0/N+, UICC/UICC I > I). MSCT imaging findings were compared with the results of TRUS and histopathology in all patients. Results: With interactive multiplanar image viewing, the results of MSCT of depth of rectal wall invasion (T-staging) were as follows: sensitivity, specificity, positive and negative predictive values, and accuracy rate were 85%, 87%, 88%, 84%, and 86% (54/63 patients) compared with 59%, 63%, 72%, 48%, and 60% (38/63 patients), respectively, for TRUS staging in the same patients. The sensitivity, specificity, positive and negative predictve values, and accuracy rate of MSCT for perirectal nodes evaluation was 75%, 85%, 75%, 85%, and 81% (51/63 patients) compared with 55%, 71%, 50%, 74%, and 65% (41/63 patients), respectively, for TRUS in detecting metastatic lymph nodes. Conclusions: Preoperative double-contrast MSCT accurately indicates the exact depth of tumor infiltration and improves lymph node staging. The new technical inovations of MSCT provide superior information for preoperative staging of rectal cancer and may compete with TRUS as the standard preoperative diagnostic method.


The Spine Journal | 2013

Papain-induced in vitro disc degeneration model for the study of injectable nucleus pulposus therapy

Samantha Chan; Alexander Bürki; Harald Marcel Bonel; Lorin Michael Benneker; Benjamin Gantenbein-Ritter

BACKGROUND CONTEXT Proteolytic enzyme digestion of the intervertebral disc (IVD) offers a method to simulate a condition of disc degeneration for the study of cell-scaffold constructs in the degenerated disc. PURPOSE To characterize an in vitro disc degeneration model (DDM) of different severities of glycosaminoglycans (GAG) and water loss by using papain, and to determine the initial response of the human mesenchymal stem cells (MSCs) introduced into this DDM. STUDY DESIGN Disc degeneration model of a bovine disc explant with an end plate was induced by the injection of papain at various concentrations. Labeled MSCs were later introduced in this model. METHODS Phosphate-buffered saline (PBS control) or papain in various concentrations (3, 15, 30, 60, and 150 U/mL) were injected into the bovine caudal IVD explants. Ten days after the injection, GAG content of the discs was evaluated by dimethylmethylene blue assay and cell viability was determined by live/dead staining together with confocal microscopy. Overall matrix composition was evaluated by histology, and water content was visualized by magnetic resonance imaging. Compressive and torsional stiffness of the DDM were also recorded. In the second part, MSCs were labeled with a fluorescence cell membrane tracker and injected into the nucleus of the DDM or a PBS control. Mesenchymal stem cell viability and distribution were evaluated by confocal microscopy. RESULTS A large drop of GAG and water content of the bovine disc were obtained by injecting >30 U/mL papain. Magnetic resonance imaging showed Grade II, III, and IV disc degeneration by injecting 30, 60, and 150 U/mL papain. A cavity in the center of the disc could facilitate later injection of the nucleus pulposus tissue engineering construct while retaining an intact annulus fibrosus. The remaining disc cell viability was not affected. Mesenchymal stem cells injected into the protease-treated DDM disc showed significantly higher cell viability than when injected into the PBS-injected control disc. CONCLUSIONS By varying the concentration of papain for injection, an increasing amount of GAG and water loss could be induced to simulate the different severities of disc degeneration. MSC suspension introduced into the disc has a very low short-term survival. However, it should be clear that this bovine IVD DDM does not reflect a clinical situation but offers exciting possibilities to test novel tissue engineering protocols.


Injury-international Journal of The Care of The Injured | 2008

Total-body digital X-ray in trauma An experience report on the first operational full body scanner in Europe and its possible role in ATLS

Aris K. Exadaktylos; Lorin Michael Benneker; V. Jeger; Luca Martinolli; Harald Marcel Bonel; Stefan Eggli; H. Potgieter; Heinz Zimmermann

When patients enter our emergency room with suspected multiple injuries, Statscan provides a full body anterior and lateral image for initial diagnosis, and then zooms in on specific smaller areas for a more detailed evaluation. In order to examine the possible role of Statscan in the management of multiply injured patients we implemented a modified ATLS((R)) algorithm, where X-ray of C-spine, chest and pelvis have been replaced by single-total a.p./lat. body radiograph. Between 15 October 2006 and 1 February 2007 143 trauma patients (mean ISS 15+/-14 (3-75)) were included. We compared the time in resuscitation room to 650 patients (mean ISS 14+/-14 (3-75)) which were treated between 1 January 2002 and 1 January 2004 according to conventional ATLS protocol. The total-body scanning time was 3.5 min (3-6 min) compared to 25.7 (8-48 min) for conventional X-rays, The total ER time was unchanged 28.7 min (13-58 min) compared to 29.1 min (15-65 min) using conventional plain radiography. In 116/143 patients additional CT scans were necessary. In 98/116 full body trauma CT scans were performed. In 18/116 patients selective CT scans were ordered based on Statscan findings. In 43/143 additional conventional X-rays had to be performed, mainly due to inadequate a.p. views of fractured bones. All radiographs were transmitted over the hospital network (Picture Archiving and Communication System, PACS) for immediate simultaneous viewing at different places. The rapid availability of images for interpretation because of their digital nature and the reduced need for repeat exposures because of faulty radiography are also felt to be strengths.


Radiology | 2012

Are There Cervical Spine Findings at MR Imaging That Are Specific to Acute Symptomatic Whiplash Injury? A Prospective Controlled Study with Four Experienced Blinded Readers

Suzanne E. Anderson; Chris Boesch; Heinz Zimmermann; André Busato; Jürg Hodler; Roland Bingisser; Erika J. Ulbrich; Andreas Nidecker; Carlos H. Buitrago-Téllez; Harald Marcel Bonel; Paul F. Heini; Stefan Schaeren; Matthias Sturzenegger

PURPOSE To compare the magnetic resonance (MR) imaging findings in patients with acute whiplash injury with those in matched control subjects. MATERIALS AND METHODS In a prospective multicenter controlled study, from 2005 to 2008, 100 consecutive patients underwent 1.5-T MR imaging examinations of the cervical spine within 48 hours after a motor vehicle accident. Findings in these patients were compared in a blinded fashion with those in 100 age- and sex-matched healthy control subjects. Four blinded independent readers assessed the presence of occult vertebral body and facet fractures, vertebral body and facet contusions, intervertebral disk herniations, ligamentum nuchae strains, ligamentum nuchae tears, muscle strains or tears, and perimuscular fluid. Accuracy (as compared with clinical findings) and interobserver reliability were calculated. RESULTS Accuracy of MR imaging and interreader reliability were generally poor (sensitivity, 0.328; specificity, 0.728; positive and negative likelihood ratios, 1.283 and 1.084, respectively). MR imaging findings significantly associated with whiplash injuries were occult fracture (P<.01), bone marrow contusion of the vertebral body (P=.01), muscle strain (P<.01) or tear (P<.01), and the presence of perimuscular fluid (P<.01). While 10 findings thought to be specific for whiplash trauma were significantly (P<.01) more frequent in patients (507 observations), they were also regularly found in healthy control subjects (237 observations). There were no serious occult injuries that required immediate therapy. CONCLUSION MR imaging at 1.5 T reveals only limited evidence of specific changes to the cervical spine and the surrounding tissues in patients with acute symptomatic whiplash injury compared with healthy control subjects.

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