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- Calon, Tim, et al.
(author)
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Multimodal analysis of the tissue response to a bone-anchored hearing implant. : 11.Calon TGA, Johansson ML, Omar O, Shah FA, Budding D, Trobos M, Thomsen P, Stokroos RJ, Palmquist
- 2019
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In: 2nd Politzer Society Meeting/2nd World Congress of Otology, 28 May - 1 June, 2019, Warsaw, Poland..
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Conference paper (other academic/artistic)
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- Johansson, Martin L, et al.
(author)
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Non-invasive sampling procedure revealing the molecular events at different abutments of bone-anchored hearing systems–A prospective clinical pilot study
- 2022
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In: Frontiers in Neuroscience. - : Frontiers Media SA. - 1662-4548 .- 1662-453X. ; 16
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Journal article (peer-reviewed)abstract
- Purpose: To investigate the molecular activities in different compartments around the bone-anchored hearing system (BAHS) with either electropolished or machined abutments and to correlate these activities with clinical and microbiological findings. Materials and methods: Twelve patients received machined or electropolished abutments after implant installation of BAHS. Peri-abutment fluid and tissue were collected from baseline to 12 months. Gene expression of cytokines and factors related to tissue healing and inflammation, regeneration and remodelling, as well as bacterial recognition were determined using quantitative-polymerase chain reaction (qPCR). The clinical status was evaluated using the Holgers scoring system, and bacterial colonisation was investigated by culturing. Results: The gene expression of inflammatory cytokines (IL-8, IL-1β, and IL-10) and bacteria-related Toll-like receptors (2 and 4) was higher in the peri-abutment fluid than at baseline and in the peri-abutment tissue at 3 and 12 months. Conversely, the expression of genes related to tissue regeneration (Coll1a1 and FOXO1) was higher in the tissue samples than in the peri-abutment fluid at 3 and 12 months. Electropolished abutments triggered higher expression of inflammatory cytokines (IL-8 and IL-1β) (in peri-abutment fluid) and regeneration factor FOXO1 (in peri-abutment tissue) than machined abutments. Several cytokine genes in the peri-abutment fluid correlated positively with the detection of aerobes, anaerobes and Staphylococcus species, as well as with high Holger scores. Conclusion: This study provides unprecedented molecular information on the biological processes of BAHS. Despite being apparently healed, the peri-abutment fluid harbours prolonged inflammatory activity in conjunction with the presence of different bacterial species. An electropolished abutment surface appears to be associated with stronger proinflammatory activity than that with a machined surface. The analysis of the peri-abutment fluid deserves further verification as a non-invasive sampling and diagnostic procedure of BAHS.
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| 5. |
- Johansson, Martin L, et al.
(author)
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Multimodal Analysis of the Tissue Response to a Bone-Anchored Hearing Implant: Presentation of a Two-Year Case Report of a Patient With Recurrent Pain, Inflammation, and Infection, Including a Systematic Literature Review.
- 2021
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In: Frontiers in cellular and infection microbiology. - : Frontiers Media SA. - 2235-2988. ; 11
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Journal article (peer-reviewed)abstract
- Osseointegration is a well-established concept used in applications including the percutaneous Bone-Anchored Hearing System (BAHS) and auricular rehabilitation. To date, few retrieved implants have been described. A systematic review including cases where percutaneous bone-anchored implants inserted in the temporal bone were retrieved and analyzed was performed. We also present the case of a patient who received a BAHS for mixed hearing loss. After the initial surgery, several episodes of soft tissue inflammation accompanied by pain were observed, leading to elective abutment removal 14 months post-surgery. Two years post-implantation, the implant was removed due to pain and subjected to a multiscale and multimodal analysis: microbial DNA using molecular fingerprinting, gene expression using quantitative real-time polymerase chain reaction (qPCR), X-ray microcomputed tomography (micro-CT), histology, histomorphometry, backscattered scanning electron microscopy (BSE-SEM), Raman spectroscopy, and fluorescence in situ hybridization (FISH). Evidence of osseointegration was provided via micro-CT, histology, BSE-SEM, and Raman spectroscopy. Polymicrobial colonization in the periabutment area and on the implant, including that with Staphylococcus aureus and Staphylococcus epidermidis, was determined using a molecular analysis via a 16S-23S rDNA interspace [IS]-region-based profiling method (IS-Pro). The histology suggested bacterial colonization in the skin and in the peri-implant bone. FISH confirmed the localization of S. aureus and coagulase-negative staphylococci in the skin. Ten articles (54 implants, 47 patients) met the inclusion criteria for the literature search. The analyzed samples were either BAHS (35 implants) or bone-anchored aural epitheses (19 implants) in situ between 2 weeks and 8years. Themainreasons for elective removal were nonuse/changes in treatment, pain, or skin reactions. Most samples were evaluated using histology, demonstrating osseointegration, but with the absence of bone under the implants' proximal flange. Taken together, the literature and this case report show clear evidence of osseointegration, despite prominent complications. Nevertheless, despite implant osseointegration, chronic pain related to the BAHS may be associated with a chronic bacterial infection and raised inflammatory response in the absence of macroscopic signs of infection. It is suggested that a multimodal analysis of peri-implant health provides possibilities for device improvements and to guide diagnostic and therapeutic strategies to alleviate the impact of complications.
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| 6. |
- Johansson, Martin L, et al.
(author)
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Clinical retrieval and analysis of percutaneous bone-anchored hearing implants using multiple analytical methodologies
- 2020
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In: 11TH WORLD BIOMATERIALS CONGRESS 11 - 15 December 2020.
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Conference paper (other academic/artistic)abstract
- Introduction: The percutaneous bone-anchored hearing system (BAHS) is an established form of hearing treatment for conductive or mixed hearing loss and single sided deafness [1]. The system consists of a titanium implant inserted in the temporal bone and mounted with an abutment onto which a sound processor is attached. It is considered to be a successful treatment with generally good outcomes in terms of audiology and quality of life [2]. However, associated adverse outcomes, such as peri-abutment inflammation and infection, pain and numbness may necessitate intervention, device removal or implant loss [2, 3]. The clinician must rely on subjective clinical measurements, whereas information on the biological events at the tissue-BAHS interface remain inaccessible. Reports of analyses of planned, electively retrieved BAHS implants, performed under perfectly controlled circumstances, are rare [4, 5]. The aim with this study was to gain insight into the biological processes around percutaneous bone-conducting devices by analysing retrieved implants. Experimental methods: Through the establishment of a bilateral collaboration network with European clinics, a retrieval and analytical protocol have been implemented. This will allow correlation of the clinical data with the underpinning microbiological, molecular and morphological fingerprints at the tissue interface. Multiple analytical and correlative strategies have been used, enabling multiscale and multimodal investigation of the tissue interface. Different sampling procedures and analytical tools were employed, including X-ray micro-computed tomography (micro-CT), histology/histomorphometry, fluorescence in situ hybridization (FISH), microbiology, quantitative polymerase chain reaction (qPCR), backscattered electron scanning electron microscopy (BSE-SEM) and Raman spectroscopy. Results and discussions: So far, retrieval, preservation and investigation of six BAHS implants with surrounding tissue have been performed. Causes for removal (1-7 years after implantation) were chronic pain, recurrent inflammation, cancer and mechanical complications. After micro-CT analysis and the samples were embedded for histological and ultrastructural analyses. This presentation describes the sample preparation route allowing assessment of the different hierarchical levels of interest of the tissue interface. Examples of the results from the different analyses will be presented, with emphasis on correlating the clinical outcome with the analytical findings. Conclusions: The implementation of a retrieval protocol combined with a subsequent multi-scale analytical strategy enables a correlation between the clinical history of patients and the underpinning microbiological, molecular and morphological events in the tissues interfacing the electively removed or failed percutaneous bone-anchored hearing implants.
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| 10. |
- Palmquist, Anders, 1977, et al.
(author)
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Long-term osseointegration of a laser ablated implant surface in a sheep model
- 2020
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In: 11TH WORLD BIOMATERIALS CONGRESS 11 - 15 December 2020.
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Conference paper (other academic/artistic)abstract
- Introduction Osseointegration, the ability for an implant to be anchorage in bone tissue with a direct bone-implant contact and allowing for continual adaptive remodeling, is clinically used in different reconstructive fields, such as dentistry, orthopedics and otology. The latter uses a bone conducting sound processor connected to a skin-penetrating abutment that is mounted on a titanium implant placed in the temporal bone acting as a path transmission for the vibrations that are generated by the sound processor The success of the treatment relies on the bone healing and osseointegration, which could be improved by surface treatments. A laser-ablated implant surface has shown good ability to osseointegrate in the long bones of rabbits at both short- and long-term in the tibia and femur[1-2]. A lighter version of the implant surface showed a good osseointegration in short-term healing in the long bone[3], however, knowledge in the harder, denser bone of the skull is lacking. The aim of the current study was to evaluate the long-term (5 month) osseointegration in a sheep skull model, and compare the osseointegration of a laser-ablated implant surface with a machined implant. Experimental methods Standard implants from Oticon Medical (Askim, Sweden), either the Wide Ponto implants with a machined surface (figure 1A, C) or Ponto BHX implants with a laser-ablated surface (figure 1B, D) were used in the current study, both with a diameter of 4.5 mm and manufactured from c.p. titanium grade 4. The surfaces were evaluated by scanning electron microscopy (Ultra 55 FEG SEM, FEI company, The Netherlands). The surgical protocol consisted of implantation in the frontal bone of 8 female sheep. The implantation was performed with a full soft tissue flap, drilling was performed using the MIPS drill-kit (Oticon Medical AB, Sweden) with a successive enlargement of the hole (diameter 3.8 mm), prior installation of the implant (test and control altered between left and right side). After 5 months, the animals were scarified, biopsies including the implant and surrounding bone tissue were immersed in formalin, prior processing for histology using plastic embedded undecalcified ground sections. Histomorphometry was performed to quantify the bone-implant contact and bone area within the treaded area of the implant. Results and discussion The animals healed well and there were no signs of adverse events after implantation or at the time of sacrifice. The histomorphometry (Figure 2) showed large amount of bone tissue around both implant types with mean values of 75% of the threaded area occupied by bone for both implant types. Large amount of bone-implant contact was observed for both implant types, with mean values between 67-71% of the surface covered by bone. This is in agreement with previous long-term rabbit study where the large amount of bone growth was observed for both implant types. No difference in the amount of bone was observed at early time point using this type of surface while the biomechanics were largely improved [3], while earlier studies have shown that the improved biomechanical properties withstand with time [2]. The current results show that the laser-ablated surface induces similar healing as the well-known clinically used machined surface in skull bone. Conclusion The laser-ablated implant performs equally well at long term as the well documented, clinically used implant with machined surface. This, together with the improved early biomechanical anchorage [3], indicate a safe and efficient clinical potential. Acknowledgements We thank Dr Måns Eeg Olofsson and Dr Erik Renvall (Sahlgrenska University Hospital, Gothenburg, Sweden) and Dr Peter Monksfield (University Hospitals Birmingham, Birmingham, UK) for performing the surgeries and retrievals. This work was supported by Oticon Medical (Askim, Sweden). References 1. Brånemark R, Emanuelsson L, Palmquist A, Thomsen P. Bone response to laser-induced micro- and nano-size titanium surface features. Nanomed - Nanotechnol Biol Med 2011;7(2):220-7. http://dx.doi.org/10.1016/j.nano.2010.10.006 2. Palmquist A, Emanuelsson L, Brånemark R, Thomsen P. Biomechanical, Histological and Ultrastructural Analyses of Laser Micro- and Nano-structured Titanium implant after 6 months in rabbit. J Biomed Mater Res B 2011;97(2):289-98. http://dx.doi.org/10.1002/jbm.b.31814 3. Shah FA, Johansson ML, Omar O, Simonsson H, Palmquist A, Thomsen P. Laser-Modified Surface Enhances Osseointegration and Biomechanical Anchorage of Commercially Pure Titanium Implants for Bone-Anchored Hearing Systems. PLoS ONE 2016;11(6):e0157504 http://dx.doi.org/10.1371/journal.pone.0157504
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