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Christine Radtke - One of the best experts on this subject based on the ideXlab platform.
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Nerve grafting for peripheral Nerve injuries with extended defect sizes
Wiener Medizinische Wochenschrift, 2019Co-Authors: Tim Kornfeld, Peter M. Vogt, Christine RadtkeAbstract:Artificial and non-artificial Nerve grafts are the gold standard in peripheral Nerve reconstruction in cases with extensive loss of Nerve tissue, particularly where a direct end-to-end suture or an autologous Nerve graft is inauspicious. Different materials are marketed and approved by the US Food and Drug Administration (FDA) for peripheral Nerve graft reconstruction. The most frequently used materials are collagen and poly(DL-lactide-e-caprolactone). Only one human Nerve allograft is listed for peripheral Nerve reconstruction by the FDA. All marketed Nerve grafts are able to demonstrate sufficient Nerve regeneration over small distances not exceeding 3.0 cm. A key question in the field is whether Nerve reconstruction on large defect lengths extending 4.0 cm or more is possible. This review gives a summary of current clinical and experimental approaches in peripheral Nerve Surgery using artificial and non-artificial Nerve grafts in short and long distance Nerve defects. Strategies to extend Nerve graft lengths for long Nerve defects, such as enhancing axonal regeneration, include the additional application of Schwann cells, mesenchymal stem cells or supporting co-factors like growth factors on defect sizes between 4.0 and 8.0 cm.
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spider silk constructs enhance axonal regeneration and remyelination in long Nerve defects in sheep
PLOS ONE, 2011Co-Authors: Christine Radtke, Christina Allmeling, Karlheinz Waldmann, Kerstin Reimers, K Thies, Henning C Schenk, Anja Hillmer, Merlin Guggenheim, Gudrun Brandes, Peter M. VogtAbstract:Background Surgical reapposition of peripheral Nerve results in some axonal regeneration and functional recovery, but the clinical outcome in long distance Nerve defects is disappointing and research continues to utilize further interventional approaches to optimize functional recovery. We describe the use of Nerve constructs consisting of decellularized vein grafts filled with spider silk fibers as a guiding material to bridge a 6.0 cm tibial Nerve defect in adult sheep. Methodology/Principal Findings The Nerve constructs were compared to autologous Nerve grafts. Regeneration was evaluated for clinical, electrophysiological and histological outcome. Electrophysiological recordings were obtained at 6 months and 10 months post Surgery in each group. Ten months later, the Nerves were removed and prepared for immunostaining, electrophysiological and electron microscopy. Immunostaining for sodium channel (NaV 1.6) was used to define nodes of Ranvier on regenerated axons in combination with anti-S100 and neurofilament. Anti-S100 was used to identify Schwann cells. Axons regenerated through the constructs and were myelinated indicating migration of Schwann cells into the constructs. Nodes of Ranvier between myelin segments were observed and identified by intense sodium channel (NaV 1.6) staining on the regenerated axons. There was no significant difference in electrophysiological results between control autologous experimental and construct implantation indicating that our construct are an effective alternative to autologous Nerve transplantation. Conclusions/Significance This study demonstrates that spider silk enhances Schwann cell migration, axonal regrowth and remyelination including electrophysiological recovery in a long-distance peripheral Nerve gap model resulting in functional recovery. This improvement in Nerve regeneration could have significant clinical implications for reconstructive Nerve Surgery.
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transplantation of olfactory ensheathing cells enhances peripheral Nerve regeneration after microsurgical Nerve repair
Brain Research, 2009Co-Authors: Christine Radtke, Peter M. Vogt, Ayal A Aizer, Samuel K Agulian, Karen L Lankford, Jeffery D KocsisAbstract:Abstract While axonal regeneration is more successful in peripheral Nerve than in the central nervous system, it is by no means complete and research to enhance peripheral Nerve regeneration is clinically important. Olfactory ensheathing cells (OECs) are known to enhance axonal regeneration and to produce myelin after transplantation. In contrast to Schwann cells their migratory potential and ability to penetrate glial scars is higher. This study evaluated the effect of OEC transplantation on microsurgically repaired sciatic Nerves. Rat sciatic Nerves were transected followed by microsurgical repair and transplantation of OECs or injection of medium without cells. Twenty-one days later the Nerves were removed and prepared for either histology or electrophysiological analysis. Footprint analysis was carried out at 7, 14 and 21 days. The OECs survived and integrated into the repaired Nerves as indicated by eGFP-expressing cells aligned with neurofilament identified axons bridging the repair site. Moreover, regenerated axons were myelinated by the transplanted OECs and nodes of Ranvier were formed. Conduction velocity in the OEC transplant group was increased in comparison to the microsurgical repair alone, and improved stepping was observed in the transplant group. These results suggest that presentation of OECs at the time of Nerve injury enhances regeneration and improves functional outcome. Even a modest improvement in Nerve regeneration could have significant clinical implications for reconstructive Nerve Surgery.
Peter M. Vogt - One of the best experts on this subject based on the ideXlab platform.
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Nerve grafting for peripheral Nerve injuries with extended defect sizes
Wiener Medizinische Wochenschrift, 2019Co-Authors: Tim Kornfeld, Peter M. Vogt, Christine RadtkeAbstract:Artificial and non-artificial Nerve grafts are the gold standard in peripheral Nerve reconstruction in cases with extensive loss of Nerve tissue, particularly where a direct end-to-end suture or an autologous Nerve graft is inauspicious. Different materials are marketed and approved by the US Food and Drug Administration (FDA) for peripheral Nerve graft reconstruction. The most frequently used materials are collagen and poly(DL-lactide-e-caprolactone). Only one human Nerve allograft is listed for peripheral Nerve reconstruction by the FDA. All marketed Nerve grafts are able to demonstrate sufficient Nerve regeneration over small distances not exceeding 3.0 cm. A key question in the field is whether Nerve reconstruction on large defect lengths extending 4.0 cm or more is possible. This review gives a summary of current clinical and experimental approaches in peripheral Nerve Surgery using artificial and non-artificial Nerve grafts in short and long distance Nerve defects. Strategies to extend Nerve graft lengths for long Nerve defects, such as enhancing axonal regeneration, include the additional application of Schwann cells, mesenchymal stem cells or supporting co-factors like growth factors on defect sizes between 4.0 and 8.0 cm.
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spider silk constructs enhance axonal regeneration and remyelination in long Nerve defects in sheep
PLOS ONE, 2011Co-Authors: Christine Radtke, Christina Allmeling, Karlheinz Waldmann, Kerstin Reimers, K Thies, Henning C Schenk, Anja Hillmer, Merlin Guggenheim, Gudrun Brandes, Peter M. VogtAbstract:Background Surgical reapposition of peripheral Nerve results in some axonal regeneration and functional recovery, but the clinical outcome in long distance Nerve defects is disappointing and research continues to utilize further interventional approaches to optimize functional recovery. We describe the use of Nerve constructs consisting of decellularized vein grafts filled with spider silk fibers as a guiding material to bridge a 6.0 cm tibial Nerve defect in adult sheep. Methodology/Principal Findings The Nerve constructs were compared to autologous Nerve grafts. Regeneration was evaluated for clinical, electrophysiological and histological outcome. Electrophysiological recordings were obtained at 6 months and 10 months post Surgery in each group. Ten months later, the Nerves were removed and prepared for immunostaining, electrophysiological and electron microscopy. Immunostaining for sodium channel (NaV 1.6) was used to define nodes of Ranvier on regenerated axons in combination with anti-S100 and neurofilament. Anti-S100 was used to identify Schwann cells. Axons regenerated through the constructs and were myelinated indicating migration of Schwann cells into the constructs. Nodes of Ranvier between myelin segments were observed and identified by intense sodium channel (NaV 1.6) staining on the regenerated axons. There was no significant difference in electrophysiological results between control autologous experimental and construct implantation indicating that our construct are an effective alternative to autologous Nerve transplantation. Conclusions/Significance This study demonstrates that spider silk enhances Schwann cell migration, axonal regrowth and remyelination including electrophysiological recovery in a long-distance peripheral Nerve gap model resulting in functional recovery. This improvement in Nerve regeneration could have significant clinical implications for reconstructive Nerve Surgery.
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transplantation of olfactory ensheathing cells enhances peripheral Nerve regeneration after microsurgical Nerve repair
Brain Research, 2009Co-Authors: Christine Radtke, Peter M. Vogt, Ayal A Aizer, Samuel K Agulian, Karen L Lankford, Jeffery D KocsisAbstract:Abstract While axonal regeneration is more successful in peripheral Nerve than in the central nervous system, it is by no means complete and research to enhance peripheral Nerve regeneration is clinically important. Olfactory ensheathing cells (OECs) are known to enhance axonal regeneration and to produce myelin after transplantation. In contrast to Schwann cells their migratory potential and ability to penetrate glial scars is higher. This study evaluated the effect of OEC transplantation on microsurgically repaired sciatic Nerves. Rat sciatic Nerves were transected followed by microsurgical repair and transplantation of OECs or injection of medium without cells. Twenty-one days later the Nerves were removed and prepared for either histology or electrophysiological analysis. Footprint analysis was carried out at 7, 14 and 21 days. The OECs survived and integrated into the repaired Nerves as indicated by eGFP-expressing cells aligned with neurofilament identified axons bridging the repair site. Moreover, regenerated axons were myelinated by the transplanted OECs and nodes of Ranvier were formed. Conduction velocity in the OEC transplant group was increased in comparison to the microsurgical repair alone, and improved stepping was observed in the transplant group. These results suggest that presentation of OECs at the time of Nerve injury enhances regeneration and improves functional outcome. Even a modest improvement in Nerve regeneration could have significant clinical implications for reconstructive Nerve Surgery.
Susan E. Mackinnon - One of the best experts on this subject based on the ideXlab platform.
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functional recovery following an end to side neurorrhaphy of the accessory Nerve to the suprascapular Nerve case report
Hand, 2010Co-Authors: Wilson Z Ray, Rahul Kasukurthi, Andrew Yee, Susan E. MackinnonAbstract:The use of end-to-side neurrorhaphy remains a controversial topic in peripheral Nerve Surgery. The authors report the long-term functional outcome following a modified end-to-side motor reinnervation using the spinal accessory to innervate the suprascapular Nerve following a C5 to C6 avulsion injury. Additionally, functional outcomes of an end-to-end neurotization of the triceps branch to the axillary Nerve and double fascicular transfer of the ulnar and medial Nerve to the biceps and brachialis are presented. Excellent functional recoveries are found in respect to shoulder abduction and flexion and elbow flexion.
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Nerve transfers in the hand and upper extremity Surgery
Techniques in Hand & Upper Extremity Surgery, 2008Co-Authors: Susan E. Mackinnon, Stephen H ColbertAbstract:Modern Nerve-to-Nerve transfers represent one of the greatest advances in peripheral Nerve Surgery. Lessons of tendon transfers have taught that Nerves to specific musculotendinous units are expendable, and greater understanding of peripheral Nerve topography has revealed redundant fascicles in peripheral Nerves. Transfer of these redundant or expendable Nerves to recipient Nerves close to the end organ allows for earlier reinnervation and preservation of those musculotendinous units. Such Nerve transfers provide significantly better treatment options in many cases of Nerve injury where previous outcomes were expected to be poor, such as with proximal injuries, long Nerve gaps, or unavailability of the proximal injured segment. This article will review current Nerve transfers in the hand and upper extremity.
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Nerve repair grafting and Nerve transfers
Clinics in Plastic Surgery, 2003Co-Authors: Linda Dvali, Susan E. MackinnonAbstract:Advances in the field of peripheral Nerve Surgery have increased our understanding of the complex cellular and molecular events involved in Nerve injury and repair. Application of these discoveries has led to important developments in the techniques of Nerve repair, Nerve grafting, and Nerve-to-Nerve transfers. This article reviews the principles and techniques of Nerve repair and discusses the options available when direct repair cannot be performed, including Nerve grafts, conduits, end-to-side repair, and Nerve-to-Nerve transfers. As our understanding of this dynamic field increases, further improvement in functional outcomes after Nerve injury and repair can be expected.
Mikael Wiberg - One of the best experts on this subject based on the ideXlab platform.
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Nerve fibre and sensory end organ density in the epidermis and papillary dermis of the human hand
British Journal of Plastic Surgery, 2005Co-Authors: Mikael Wiberg, Edward J Kelly, Giorgio Terenghi, A HazariAbstract:Quantification of sensory recovery after peripheral Nerve Surgery is difficult and no accurate techniques are available at present. Quantification of reinnervated skin has been used experimentally, and in some clinical studies, but the lack of knowledge about the normal sensory distribution has been a problem. The purpose of this study was, therefore, to map the density of sensory end organs, Nerve fibres and free Nerve endings in the glabrous skin of the human hand. Skin biopsies were taken from patients undergoing acute and elective hand Surgery. Nerve fibres were stained in the epidermis and papillary dermis and quantified in five sites on the palm of the hand, using protein gene product 9.5 immunoreactivity-a panneuronal marker. The finger tip skin was found to have more than twice the Nerve fibre density in the papillary dermis than the skin of the palm, and the number of Meissner corpuscles in the finger tip was also higher than in the palm. We found a reduction in innervation density with increasing age in the dermis, however, that was not the case for the epidermis. The innervation of the epidermis showed high interindividual variability and unlike the papillary dermis did not display any pattern of distribution in the hand.
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neuronal survival using a resorbable synthetic conduit as an alternative to primary Nerve repair
Microsurgery, 1999Co-Authors: Christina Ljungberg, G Johanssonruden, K J Bostrom, Lev N Novikov, Mikael WibergAbstract:: Clinically optimal situations for primary Nerve repair are rarely observed. Crushed Nerve ends result in either suboptimal repair or a need for Nerve grafting. Functional results after Nerve Surgery are relatively poor, including major sensory deficits, which may be due to the death of primary sensory neurons that follows the Nerve injury. The aim of this study was to determine if using polyhydroxybutyrate (PHB), a resorbable Nerve conduit, could be an alternative to primary Nerve repair in reducing loss of neurons. The superficial radial Nerves in 20 cats were sectioned bilaterally and primarily repaired microsurgically by the use of two different strategies; either wrapping the Nerve ends in sheets of PHB or epineurally suturing of the Nerve. After 6 or 12 months, the surviving neurons within the dorsal root ganglia [C5-T1] were counted. No statistically significant differences were found between the two methods. This may imply a future possibility of using PHB as a synthetic Nerve graft in situations where suboptimal primary repair or Nerve grafts are the alternatives.
Ash Mosahebi - One of the best experts on this subject based on the ideXlab platform.
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Nerve conduits for peripheral Nerve Surgery
Plastic and Reconstructive Surgery, 2014Co-Authors: Amit Pabari, Hawys Lloydhughes, Alexander M Seifalian, Ash MosahebiAbstract:Autologous Nerve grafts are the current criterion standard for repair of peripheral Nerve injuries when the transected Nerve ends are not amenable to primary end-to-end tensionless neurorrhaphy. However, donor-site morbidities such as neuroma formation and permanent loss of function have led to tremendous interest in developing an alternative to this technique. Artificial Nerve conduits have therefore emerged as an alternative to autologous Nerve grafting for the repair of short peripheral Nerve defects of less than 30 mm; however, they do not yet surpass autologous Nerve grafts clinically. A thorough understanding of the complex biological reactions that take place during peripheral Nerve regeneration will allow researchers to develop a Nerve conduit with physical and biological properties similar to those of an autologous Nerve graft that supports regeneration over long Nerve gaps and in large-diameter Nerves. In this article, the authors assess the currently available Nerve conduits, summarize research in the field of developing these conduits, and establish areas within this field in which further research would prove most beneficial.