Nerve Grafts (nerve + graft)

Distribution by Scientific Domains

Kinds of Nerve Grafts

  • acellular nerve graft


  • Selected Abstracts


    Rabbit Facial Nerve Regeneration in Autologous Nerve Grafts After Antecedent Injury ,

    THE LARYNGOSCOPE, Issue 4 2000
    FACS, J. Gershon Spector MD
    Objective The effect of incomplete antecedent injuries on subsequent facial nerve regeneration within cable graft repairs is not known. The purpose of this study is to compare facial nerve regeneration after an immediate and delayed neural cable graft repair. Method Rabbit facial nerve regeneration after complete transectional injuries of the buccal division was compared in two experimental models. In one, a 10-mm segment of the nerve was transected, rotated 180°, and immediately repaired as a cable graft (N=8). In the second, a preliminary nerve crush was allowed to recover over a 4-week period and a 10-mm segment of nerve centered on the crush site was then transected, rotated 180°, and delay repaired as a cable graft (N = 7). Data are presented as total numbers of regenerating myelinated axons that traverse the surgical repair to innervate the cable graft and distal nerve stumps, as well as the percentage of regenerating neurites compared with preoperative pooled and individual controls. Subpopulations of regenerating neurons are delineated to quantify the pattern of neural innervation. Results Five weeks after cable graft repair both groups had similar myelinated outgrowth from the proximal nerve stump across the proximal anastomosis to innervate the cable graft (3995 ± 1209 vs. 3284 ± 651;P = .89). However, the delayed repair group had more intrafascicular regeneration within cable grafts (2261 ± 931 vs. 1660 ± 1169;P = .02) and distal nerve stump (1532 ± 281 vs. 445 ± 120;P = .004) than the immediate repair group. The immediate repair group had greater extrafascicular nerve regeneration in the cable graft (2335 ± 1954 vs. 437 ± 236;P = .001) and more myelin and axonal debris in pre-existing neural fascicles of the cable graft (P = .02) and distal nerve stump (463 ± 187 vs. 103 ± 87;P = .02). Conclusions Antecedent priming lesions do not enhance axonal survival as determined by regenerating myelinated axonal counts. However, antecedent injuries enhance the efficiency of neural innervation of the affected mimetic musculature by increasing the number of myelinated intrafascicular neural regenerants in the cable graft and distal nerve stump. This is accomplished by two factors: increased perineural fibrosis and decreased intrafascicular myelin and axonal debris. [source]


    Brain-derived neurotrophic factor applied to the motor cortex promotes sprouting of corticospinal fibers but not regeneration into a peripheral nerve transplant

    JOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2002
    G.W. Hiebert
    Abstract Previous experiments from our laboratory have shown that application of brain-derived neurotrophic factor (BDNF) to the red nucleus or the motor cortex stimulates an increase in the expression of regeneration-associated genes in rubrospinal and corticospinal neurons. Furthermore, we have previously shown that BDNF application stimulates regeneration of rubrospinal axons into a peripheral graft after a thoracic injury. The current study investigates whether application of BDNF to the motor cortex will facilitate regeneration of corticospinal neurons into a peripheral nerve graft placed into the thoracic spinal cord. In adult Sprague Dawley rats, the dorsal columns and the corticospinal tract between T9 and T10 were ablated by suction, and a 5-mm-long segment of predegenerated tibial nerve was autograft implanted into the lesion. With an osmotic pump, BDNF was infused directly into the parenchyma of the motor cortex for 14 days. Growth of the corticospinal tract into the nerve graft was then evaluated by transport of an anterograde tracer. Anterogradely labeled corticospinal fibers were not observed in the peripheral nerve graft in animals treated with saline or BDNF. Serotinergic and noradrenergic fibers, as well as peripheral sensory afferents, were observed to penetrate the graft, indicating the viability of the peripheral nerve graft as a permissive growth substrate for these specific fiber types. Although treatment of the corticospinal fibers with BDNF failed to produce regeneration into the graft, there was a distinct increase in the number of axonal sprouts rostral to the injury site. This indicates that treatment of corticospinal neurons with neurotrophins, e.g., BDNF, can be used to enhance sprouting of corticospinal axons within the spinal cord. Whether such sprouting leads to functional recovery after spinal cord injury is currently under investigation. © 2002 Wiley-Liss, Inc. [source]


    Tissue engineering of peripheral nerves: Epineurial grafts with application of cultured Schwann cells

    MICROSURGERY, Issue 1 2003
    H. Fansa M.D., Ph.D.
    After a simple nerve lesion, primary microsurgical suture is the treatment of choice. A nerve gap has to be bridged, with a nerve graft sacrificing a functioning nerve. Alternatively, tissue engineering of nerve grafts has become a subject of experimental research. It is evident that nerve regeneration requires not only an autologous, allogenous, or biodegradable scaffold, but additional interactions with regeneration-promoting Schwann cells. In this study, we compared epineurial and acellularized epineurial tubes with and without application of cultured Schwann cells as alternative grafts in a rat sciatic nerve model. Autologous nerve grafts served as controls. Evaluation was performed after 6 weeks; afterwards, sections of the graft and distal nerve were harvested for histological and morphometrical analysis. Compared to controls, all groups showed a significantly lower number of axons, less well-shaped remyelinizated axons, and a delay in clinical recovery (e.g., toe spread). The presented technique with application of Schwann cells into epineurial tubes did not offer any major advantages for nerve regeneration. Thus, in this applied model, neither the implantation of untreated nor the implantation of acellularized epineurial tubes with cultured Schwann cells to bridge nerve defects was capable of presenting a serious alternative to the present gold standard of conventional nerve grafts for bridging nerve defects in this model. © 2003 Wiley-Liss, Inc. MICROSURGERY 23:72,77 2003 [source]


    Nerve regeneration through an epineurial sheath: Its functional aspect compared with nerve and vein grafts

    MICROSURGERY, Issue 5 2001
    Ercan Karacao, lu M.D.
    Although nerve graft is still the only reliable choice in repair of defects in peripheral nerve structure, it has the disadvantage of donor nerve morbidity and of sometimes being unavailable. It has long been researched in alternate nerve grafts with other materials. Studies have shown that nerves could regenerate across short nerve gaps through various conduits, such as veins, pseudosheaths, and bioabsorbable tubes. Despite encouraging studies, their functional results remain unclear. The present study used 40 rats, in which nerve grafts, vein grafts, and epineurial tubes were placed into 1-cm gaps in sciatic nerves created by resection. In one group, sciatic nerves were denuded of the surrounding epineurium, to assess the possible morbidity caused by epineurial sheath technique. At 2, 4, 8, 12, 20, and 28 weeks, functional assessment of nerve regeneration was performed using walking track analysis. The number of myelinated fibers and fiber diameters was measured and electron microscopic evaluation performed. Functionally, the index values were very close to each other in nerve graft and epineurial sheath groups. Morphometric analysis showed significance between the groups. The result of denuded sciatic nerve group was the same as the base track values. It was concluded that the ready availability of epineurial sheath as a conduit to span short nerve gaps could eliminate the morbidity associated with nerve graft harvest and capitalize on the potential benefits of neurotrophism in directing nerve regeneration. © 2001 Wiley-Liss, Inc. Microsurgery 21:196,201 2001 [source]


    Experimental study of vascularized nerve graft: Evaluation of nerve regeneration using choline acetyltransferase activity

    MICROSURGERY, Issue 2 2001
    Makoto Iwai M.D.
    A comparative study of nerve regeneration was performed on vascularized nerve graft (VNG) and free nerve graft (FNG) in Fischer strain rats. A segment of the sciatic nerve with vascular pedicle of the femoral artery and vein was harvested from syngeneic donor rat for the VNG group and the sciatic nerve in the same length without vascular pedicle was harvested for the FNG group. They were transplanted to a nerve defect in the sciatic nerve of syngeneic recipient rats. At 2, 4, 6, 8, 12, 16, and 24 weeks after operation, the sciatic nerves were biopsied and processed for evaluation of choline acetyltransferase (CAT) activity, histological studies, and measurement of wet weight of the muscle innervated by the sciatic nerve. Electrophysiological evaluation of the grafted nerve was also performed before sacrifice. The average CAT activity in the distal to the distal suture site was 383 cpm in VNG and 361 cpm in FNG at 2 weeks; 6,189 cpm in VNG and 2,264 cpm in FNG at 4 weeks; and 11,299 cpm in VNG and 9,424 cpm in FNG at 6 weeks postoperatively. The value of the VNG group was statistically higher than that of the FNG group at 4 weeks postoperatively. Electrophysiological and histological findings also suggested that nerve regeneration in the VNG group was superior to that in the FNG group during the same period. However, there was no significant difference between the two groups after 6 weeks postoperatively in any of the evaluations. The CAT measurement was useful in the experiments, because it was highly sensitive and reproducible. © 2001 Wiley-Liss, Inc. MICROSURGERY 24:43,51 2001 [source]


    Outcomes of static and dynamic facial nerve repair in head and neck cancer

    THE LARYNGOSCOPE, Issue 3 2010
    Tim A. Iseli MBBS
    Abstract Objectives/Hypothesis: Determine outcomes associated with nerve grafting versus static repair following facial nerve resection. Study Design: Retrospective chart review. Methods: Charts from 105 patients who underwent facial nerve reconstruction between January 1999 and January 2009 were reviewed. The majority had parotid malignancy (78.1%), most commonly squamous cell carcinoma (50.5%). Patients underwent static (n = 72) or dynamic (n = 33) reconstruction with nerve grafting. Facial nerve function was measured using the House-Brackmann (H-B) scale. Results: Patients receiving static reconstruction were on average 10.3 years older (P = .002). Mean overall survival for tumor cases was 61.9 months; parotid squamous cell carcinoma was associated with worse prognosis (P = .10). Median follow-up was 16.1 months (range, 4,96.1 months). Most (97%) patients receiving a nerve graft had some return of function at a median of 6.2 months postoperatively (range, 4,9 months) and the majority (63.6%) had good function (H-B score ,4). Patients having static reconstruction (29.2%) were more likely to have symptomatic facial palsy than those having a nerve graft (15.2%, P = .12). Conclusions: Where possible, nerve grafting is the preferred method of facial nerve reconstruction. Although elderly patients with parotid malignancy have traditionally been considered poor candidates for nerve grafting, we demonstrate good results within 9 months of facial nerve repair even with radiotherapy, the use of long grafts (>6 cm), and prolonged preoperative dysfunction. Laryngoscope, 2010 [source]


    Repair of the trigeminal nerve: a review

    AUSTRALIAN DENTAL JOURNAL, Issue 2 2010
    RHB Jones
    Abstract Nerve surgery in the maxillofacial region is confined to the trigeminal and facial nerves and their branches. The trigeminal nerve can be damaged as a result of trauma, local anaesthesia, tumour removal and implant placement but the most common cause relates to the removal of teeth, particularly the inferior alveolar and lingual nerves following third molar surgery. The timing of nerve repair is controversial but it is generally accepted that primary repair at the time of injury is the best time to repair the nerve but it is often a closed injury and the operator does not know the nerve is injured until after the operation. Early secondary repair at about three months after injury is the most accepted time frame for repair. However, it is also thought that a reasonable result can be obtained at a later time. It is also generally accepted that the best results will be obtained with a direct anastamosis of the two ends of the nerve to be repaired. However, if there is a gap between the two ends, a nerve graft will be required to bridge the gap as the two ends of the nerve will not be approximated without tension and a passive repair is important for the regenerating axons to grow down the appropriate perineural tubes. Various materials have been used for grafting and include autologous grafts, such as the sural and greater auricular nerves, vein grafts, which act as a conduit for the axons to grow down, and allografts such as Neurotube, which is made of polyglycolic acid (PGA) and will resorb over a period of time. [source]


    Schwann cell delivery of neurotrophic factors for peripheral nerve regeneration

    JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2010
    Srinivas Madduri
    Current treatments of injured peripheral nerves often fail to mediate satisfactory functional recovery. For axonal regeneration, neurotrophic factors (NTFs) play a crucial role. Multiple NTFs and other growth-promoting factors are secreted, amongst others, by Schwann cells (SCs), which also provide cellular guidance for regenerating axons. Therefore, delivery of NTFs and transplantation of autologous or genetically modified SCs with therapeutic protein expression have been proposed. This article reviews polymer-based and cellular approaches for NTF delivery, with a focus on SCs and strategies to modulate SC gene expression. Polymer-based NTF delivery has mostly resided on nerve conduits (NC). While NC have generally provided prolonged NTF release, their therapeutic effect has remained significantly below that achieved with autologous nerve grafts. Several studies demonstrated enhanced nerve regeneration using NC seeded with SCs. The SCs have sometimes been modified genetically using non-viral or viral vectors. Whereas non-viral vectors produced poor transgene delivery, adenoviral vectors mediated high transgene transduction efficiency of SCs. Further improvements of safety and transgene expression of adenoviral vector may lead to rapid translation of pre-clinical research to clinical trials. [source]


    Hyperbaric oxygen treatment has different effects on nerve regeneration in acellular nerve and muscle grafts

    JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2001
    Yasumasa Nishiura
    Abstract Effects of hyperbaric oxygen treatment (HBO) on nerve regeneration in acellular nerve and muscle grafts were investigated in rats. Nerve and muscle grafts were made acellular by freeze-thawing and the obtained grafts were used to bridge a 10-mm gap in the sciatic nerve on the left and right sides, respectively. Rats were treated with HBO (100% oxygen for 90 minutes at 2.5 atmospheres absolute pressure ATA) twice a day for 7 days. Axonal outgrowth, Schwann cell migration and invasion of macrophages were examined 10 days after the graft procedure by staining neurofilaments, S-100 proteins and the macrophage antibodies ED1 and ED2, respectively. Axonal outgrowth and Schwann cell migration in acellular nerve grafts were superior to that found in the acellular muscle grafts. However, there was no difference between HBO-treated and non-treated rats in acellular nerve grafts. Such a difference was found in acellular muscle grafts concerning both axonal outgrowth and Schwann cell migration from the proximal nerve end. No differences in the content of macrophages or neovascularization (alkaline phosphatase staining) in either of the grafts and treatments were seen. It is concluded that there is a differential effect of HBO-treatment in acellular nerve and muscle grafts and that HBO-treatment has no effect on the regeneration process in acellular nerve grafts, in contrast to fresh cellular nerve grafts where a beneficial effect has previously been reported. [source]


    Improvement of peripheral nerve regeneration in acellular nerve grafts with local release of nerve growth factor

    MICROSURGERY, Issue 4 2009
    Hailong Yu M.D.
    Previous studies have demonstrated the potential of growth factors in peripheral nerve regeneration. A method was developed for sustained delivery of nerve growth factor (NGF) for nerve repair with acellular nerve grafts to augment peripheral nerve regeneration. NGF-containing polymeric microspheres were fixed with fibrin glue around chemically extracted acellular nerve grafts for prolonged, site-specific delivery of NGF. A total of 52 Wister rats were randomly divided into four groups for treatment: autografting, NGF-treated acellular grafting, acellular grafting alone, and acellular grafting with fibrin glue. The model of a 10-mm sciatic nerve with a 10-mm gap was used to assess nerve regeneration. At the 2nd week after nerve repair, the length of axonal regeneration was longer with NGF-treated acellular grafting than acellular grafting alone and acellular grafting with fibrin glue, but shorter than autografting (P < 0.05). Sixteen weeks after nerve repair, nerve regeneration was assessed functionally and histomorphometrically. The percentage tension of the triceps surae muscles in the autograft group was 85.33 ± 5.59%, significantly higher than that of NGF-treated group, acellular graft group and fibrin-glue group, at 69.79 ± 5.31%, 64.46 ± 8.48%, and 63.35 ± 6.40%, respectively (P < 0.05). The ratio of conserved muscle-mass was greater in the NGF-treated group (53.73 ± 4.56%) than in the acellular graft (46.37 ± 5.68%) and fibrin glue groups (45.78 ± 7.14%) but lower than in the autograft group (62.54 ± 8.25%) (P < 0.05). Image analysis on histological observation revealed axonal diameter, axon number, and myelin thickness better with NGF-treated acellular grafting than with acellular grafting alone and acellular grafting with fibrin glue (P < 0.05). There were no significant differences between NGF-treated acellular grafting and autografting. This method of sustained site-specific delivery of NGF can enhance peripheral nerve regeneration across short nerve gaps repaired with acellular nerve grafts. © 2009 Wiley-Liss, Inc. Microsurgery, 2009. [source]


    Tissue engineering of peripheral nerves: Epineurial grafts with application of cultured Schwann cells

    MICROSURGERY, Issue 1 2003
    H. Fansa M.D., Ph.D.
    After a simple nerve lesion, primary microsurgical suture is the treatment of choice. A nerve gap has to be bridged, with a nerve graft sacrificing a functioning nerve. Alternatively, tissue engineering of nerve grafts has become a subject of experimental research. It is evident that nerve regeneration requires not only an autologous, allogenous, or biodegradable scaffold, but additional interactions with regeneration-promoting Schwann cells. In this study, we compared epineurial and acellularized epineurial tubes with and without application of cultured Schwann cells as alternative grafts in a rat sciatic nerve model. Autologous nerve grafts served as controls. Evaluation was performed after 6 weeks; afterwards, sections of the graft and distal nerve were harvested for histological and morphometrical analysis. Compared to controls, all groups showed a significantly lower number of axons, less well-shaped remyelinizated axons, and a delay in clinical recovery (e.g., toe spread). The presented technique with application of Schwann cells into epineurial tubes did not offer any major advantages for nerve regeneration. Thus, in this applied model, neither the implantation of untreated nor the implantation of acellularized epineurial tubes with cultured Schwann cells to bridge nerve defects was capable of presenting a serious alternative to the present gold standard of conventional nerve grafts for bridging nerve defects in this model. © 2003 Wiley-Liss, Inc. MICROSURGERY 23:72,77 2003 [source]


    Nerve regeneration through a healthy peripheral nerve trunk as a nerve conduit: A preliminary study of a new concept in peripheral nerve surgery

    MICROSURGERY, Issue 4 2002
    Fuat Yüksel M.D.
    The popularity of nerve conduits has increased recently due to the need for alternative nerve reconstruction techniques, obviating the harvest of nerve grafts. Based on ideas suggesting nerve tissue itself, which was the most physiologic environment for nerve regeneration, a study using 40 sciatic nerves of 20 rats was performed. The proximal stumps of transected peroneal nerves were sutured to the lateral wall of healthy tibial nerve trunks after removal of the epineurium. Twelve weeks later, tissue samples were taken from the anastomosis sites and from the levels above and below these sites. Configurations of fascicles were evaluated, and numbers of fibers were estimated. It was observed that the fibers of peroneal nerves regenerated into and through the tibial nerve trunk distally. This suggested that active regenerating fibers of a proximal stump of a nerve could regenerate and progress as a fascicular unit in optimum condition at the trunk of another healthy nerve. This preliminary study should stimulate further studies based on this new concept: that a nerve trunk can serve as the host for the regenerating fibers of another nerve. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:138,143 2002 [source]


    Nerve regeneration through an epineurial sheath: Its functional aspect compared with nerve and vein grafts

    MICROSURGERY, Issue 5 2001
    Ercan Karacao, lu M.D.
    Although nerve graft is still the only reliable choice in repair of defects in peripheral nerve structure, it has the disadvantage of donor nerve morbidity and of sometimes being unavailable. It has long been researched in alternate nerve grafts with other materials. Studies have shown that nerves could regenerate across short nerve gaps through various conduits, such as veins, pseudosheaths, and bioabsorbable tubes. Despite encouraging studies, their functional results remain unclear. The present study used 40 rats, in which nerve grafts, vein grafts, and epineurial tubes were placed into 1-cm gaps in sciatic nerves created by resection. In one group, sciatic nerves were denuded of the surrounding epineurium, to assess the possible morbidity caused by epineurial sheath technique. At 2, 4, 8, 12, 20, and 28 weeks, functional assessment of nerve regeneration was performed using walking track analysis. The number of myelinated fibers and fiber diameters was measured and electron microscopic evaluation performed. Functionally, the index values were very close to each other in nerve graft and epineurial sheath groups. Morphometric analysis showed significance between the groups. The result of denuded sciatic nerve group was the same as the base track values. It was concluded that the ready availability of epineurial sheath as a conduit to span short nerve gaps could eliminate the morbidity associated with nerve graft harvest and capitalize on the potential benefits of neurotrophism in directing nerve regeneration. © 2001 Wiley-Liss, Inc. Microsurgery 21:196,201 2001 [source]


    The use of vein grafts in the repair of the inferior alveolar nerve following surgery

    AUSTRALIAN DENTAL JOURNAL, Issue 2 2010
    RHB Jones
    Abstract Damage to the branches of the trigeminal nerve can occur as a result of a variety of causes. The most common damage to all divisions of this nerve occurs as a result of facial trauma. Unfortunately, iatrogenic damage to the inferior alveolar branch of the mandibular division of the trigeminal nerve is common because of its anatomical position within the mandible and its closeness to the teeth, particularly the third molar. It has been reported there is an incidence of approximately 0.5% of permanent damage to the inferior alveolar nerve following third molar removal. Extraction of other teeth within the mandible carries a lower incidence of permanent damage. However, damage can still occur in the premolar area, where the nerve exits the mandible via the mental foramen. Dental implants are a relatively new but increasing cause of damage to this nerve, particularly if the preoperative planning is inadequate. CT scanning is important for planning the placement of implants if this damage is to be reduced. Primary repair of the damaged nerve will offer the best chance of recovery. However, if there is a gap, and the nerve ends cannot be approximated without tension, a graft is required. Traditionally, nerve grafts have been used for this purpose but other conduits have also been used, including vein grafts. This article demonstrates the use of vein grafts in the reconstruction of the inferior dental branch of the mandibular division of the trigeminal nerve following injury, in this case due to difficulty in third molar removal, following sagittal split osteotomy and during the removal of a benign tumour from the mandible. In the five cases presented, this technique has demonstrated good success, with an acceptable return of function occurring in most patients. [source]


    Spider silk fibres in artificial nerve constructs promote peripheral nerve regeneration

    CELL PROLIFERATION, Issue 3 2008
    C. Allmeling
    Materials and methods: We compared isogenic nerve grafts to vein grafts with spider silk fibres, either alone or supplemented with Schwann cells, or Schwann cells and matrigel. Controls, consisting of veins and matrigel, were transplanted. After 6 months, regeneration was evaluated for clinical outcome, as well as for histological and morphometrical performance. Results: Nerve regeneration was achieved with isogenic nerve grafts as well as with all constructs, but not in the control group. Effective regeneration by isogenic nerve grafts and grafts containing spider silk was corroborated by diminished degeneration of the gastrocnemius muscle and by good histological evaluation results. Nerves stained for S-100 and neurofilament indicated existence of Schwann cells and axonal re-growth. Axons were aligned regularly and had a healthy appearance on ultrastructural examination. Interestingly, in contrast to recently published studies, we found that bridging an extensive gap by cell-free constructs based on vein and spider silk was highly effective in nerve regeneration. Conclusion: We conclude that spider silk is a viable guiding material for Schwann cell migration and proliferation as well as for axonal re-growth in a long-distance model for peripheral nerve regeneration. [source]