Autologous fibrin glue in peripheral nerve regeneration in vivo

Nerve Reconstruction Using ActiGraft Blood Clot in Rabbit Acute Peripheral Injury Model: Preliminary Study

This preliminary study aimed to investigate an ActiGraft blood clot implant (RedDress Ltd., Pardes-Hanna, Israel) attempting to treat and induce the regeneration of a completely injured peripheral nerve with a massive loss defect. The tibial portion of the sciatic nerve in 11 rabbits was transected, and a 25 mm nerve gap was reconnected using a collagen tube. A comparison was performed between the treatment group (eight rabbits; reconnection using a tube filled with ActiGraft blood clot) and the control group (three rabbits; gap reconnection using an empty tube). The post-operative follow-up period lasted 18 weeks and included electrophysiological and histochemical assessments. The pathological severity score was high in the tube cross sections of the control group (1.33) compared to the ActiGraft blood clot treatment group (0.63). Morphometric analysis showed a higher percentage of the positive myelin basic protein (MBP) stained area in the ActiGraft blood clot group (19.57%) versus the control group (3.67%). These differences were not statistically significant due to the small group sizes and the large intra-group variability. The results of this preliminary study suggest that the application of an ActiGraft blood clot (into the collagen tube) can enable nerve recovery. However, a future study using a larger animal group is required to achieve objective statistical results.

Morphofunctional Improvement of the Facial Nerve and Muscles with Repair Using Heterologous Fibrin Biopolymer and Photobiomodulation

Peripheral nerve injuries impair the patient's functional capacity, including those occurring in the facial nerve, which require effective medical treatment. Thus, we investigated the use of heterologous fibrin biopolymer (HFB) in the repair of the buccal branch of the facial nerve (BBFN) associated with photobiomodulation (PBM), using a low-level laser (LLLT), analyzing the effects on axons, muscles facials, and functional recovery. This experimental study used twenty-one rats randomly divided into three groups of seven animals, using the BBFN bilaterally (the left nerve was used for LLLT): Control group-normal and laser (CGn and CGl); Denervated group-normal and laser (DGn and DGl); Experimental Repair Group-normal and laser (ERGn and ERGl). The photobiomodulation protocol began in the immediate postoperative period and continued for 5 weeks with a weekly application. After 6 weeks of the experiment, the BBFN and the perioral muscles were collected. A significant difference (p < 0.05) was observed in nerve fiber diameter (7.10 ± 0.25 µm and 8.00 ± 0.36 µm, respectively) and axon diameter (3.31 ± 0.19 µm and 4.07 ± 0.27 µm, respectively) between ERGn and ERGl. In the area of muscle fibers, ERGl was similar to GC. In the functional analysis, the ERGn and the ERGI (4.38 ± 0.10) and the ERGI (4.56 ± 0.11) showed parameters of normality. We show that HFB and PBM had positive effects on the morphological and functional stimulation of the buccal branch of the facial nerve, being an alternative and favorable for the regeneration of severe injuries.

Autologous Fibrin Glue Versus Microsuture in the Surgical Reconstruction of Peripheral Nerves: A Randomized Clinical Trial

PURPOSE

This study compared the motor and sensory recovery and the operative time of autologous fibrin glue application with conventional microsuturing technique in repairing peripheral nerves at the forearm and wrist levels METHODS: Eighty-five patients with injuries of the median, ulnar, or both nerves at the wrist and forearm levels underwent nerve repair between September 2014 and June 2018. Patients were randomly assigned at the time of diagnosis to a microsuture group (42 patients), in which standard epineurial microsurgical suturing was performed, or a fibrin glue group (43 patients), in which nerve repair was performed using autologous fibrin glue. The primary outcome measure was motor and sensory recovery. Operative time was the secondary outcome measure. Other outcome measures that were added post hoc, after trial initiation, included time to motor and sensory recovery; grip strength; pinch strength; Michigan hand outcome score; amplitude, latency, and duration of the compound motor unit action potential; and complications. All patients were followed up a minimum of 1 year.

RESULTS

At the final follow-up, both groups had regained similar motor and sensory function. The mean operative time was shorter in the fibrin glue group. Both groups had similar amplitude, latency, and duration of the compound motor unit action potential. Michigan Hand Outcome scores and mean percent recovery of grip strength and pinch strength were also similar. Six of 43 patients in the fibrin glue group compared with 8 of 42 patients in the microsuture group developed postoperative complications.

CONCLUSIONS

The use of fibrin glue to repair peripheral nerves is as effective as microsuturing in regaining motor and sensory functions and is associated with shorter operative time.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

Functional Recovery following Repair of Long Nerve Gaps in Senior Patient 2.6 Years Posttrauma

Sensory nerve grafts are the clinical “gold standard” for repairing peripheral nerve gaps. However, reliable good-to-excellent recovery develops only for gaps less than 3–5 cm, repairs performed less than 3–5 months posttrauma, and patients aged less than 20–25 years. As the value of any variable increases, the extent of recovery decreases precipitously, and if the values of any two or all increase, there is little to no recovery. One 9-cm-long and two 11-cm-long nerve gaps in a 56-year-old patient were repaired 2.6 years posttrauma. They were bridged with two sensory nerve grafts within an autologous platelet-rich plasma-filled collagen tube. Both were connected to the proximal ulnar nerve stump, with one graft end to the distal motor and the other to the sensory nerve branches. Although presurgery the patient suffered chronic level 10 excruciating neuropathic pain, it was reduced to 6 within 2 months, and did not increase for more than 2 years. Motor axons regenerated across the 9-cm gap and innervated the appropriate two measured muscles, with limited muscle fiber recruitment. Sensory axons regenerated across both 11-cm gaps and restored normal topographically correct sensitivity to stimuli of all sensory modalities, including static two-point discrimination of 5 mm, and pressure of 2.83 g to all regions innervated by both sensory nerves. This novel technique induced a significant long-term reduction in chronic excruciating neuropathic pain while promoting muscle reinnervation and complete sensory recovery, despite the values of all three variables that reduce or prevent axon regeneration and recovery being simultaneously large.

Differential effects of rat ADSCs encapsulation in fibrin matrix and combination delivery of BDNF and Gold nanoparticles on peripheral nerve regeneration

Background

Fibrin as an extracellular matrix feature like biocompatibility, creates a favorable environment for proliferation and migration of cells and it can act as a reservoir for storage and release of growth factors in tissue engineering.

Methods

In this study, the inner surface of electrospun poly (lactic-co-glycolic acid) (PLGA) nanofibrous conduit was biofunctionalized with laminin containing brain derived neurotrophic factor (BDNF) and gold nanoparticles in chitosan nanoparticle. The rats were randomly divided into five groups, including autograft group as the positive control, PLGA conduit coated by laminin and filled with DMEM/F12, PLGA conduit coated by laminin and filled with rat-adipose derived stem cells (r-ADSCs), PLGA conduit coated by laminin containing gold-chitosan nanoparticles (AuNPs-CNPs), BDNF-chitosan nanoparticles (BDNF-CNPs) and filled with r-ADSCs or filled with r-ADSCs suspended in fibrin matrix, and they were implanted into a 10 mm rat sciatic nerve gap. Eventually, axonal regeneration and functional recovery were assessed after 12 weeks.

Results

After 3 months post-surgery period, the results showed that in the PLGA conduit filled with r-ADSCs without fibrin matrix group, positive effects were obtained as compared to other implanted groups by increasing the sciatic functional index significantly (p < 0.05). In addition, the diameter nerve fibers had a significant difference mean in the PLGA conduit coated by laminin and conduit filled with r-ADSCs in fibrin matrix groups relative to the autograft group (p < 0.001). However, G-ratio and amplitude (AMP) results showed that fibrin matrix might have beneficial effects on nerve regeneration but, immunohistochemistry and real-time RT-PCR outcomes indicated that the implanted conduit which filled with r-ADSCs, with or without BDNF-CNPs and AuNPs-CNPs had significantly higher expression of S100 and MBP markers than other conduit implanted groups (p < 0.05).

Conclusions

It seems, in this study differential effects of fibrin matrix, could be interfered it with other factors thereby and further studies are required to determine the distinctive effects of fibrin matrix combination with other exogenous factors in peripheral nerve regeneration.

Foot Reanimation Using Double Nerve Transfer to Deep Peroneal Nerve: A Novel Technique for Treatment of Neurologic Foot Drop

BACKGROUND

Our primary objective was to assess the efficacy of a new technique for foot reanimation in patients with neurologic foot drop using double nerve transfer from the tibial to the deep peroneal nerve. Our secondary objective was to document the technical nuances of our technique.

METHODS

Thirty-one patients with common peroneal nerve injury between October 2015 and March 2019 were prospectively enrolled in the study. Patients underwent a transfer of the tibial nerve branches to flexor digitorum longus and lateral head of gastrocnemius to the deep peroneal nerve. Motor recovery, range of ankle dorsiflexion, pain, leg girth, and complications were examined as outcome measures. The modified Medical Research Council (MRC) scale was adopted to assess the motor power recovery. All patients were followed up for a minimum of 1 year.

RESULTS

Motor recovery of M3 or M4 grade of tibialis anterior, extensor hallucis longus, and extensor digitorum longus was achieved in 15 of 31, 13 of 31, and 12 of 31 patients, respectively. Those patients could discontinue use of orthosis. Most patients with high-energy traumas or knee-level injuries failed to recover antigravity function. Only 2 patients reported weak postoperative toe plantarflexion. Our patients achieved significant improvement of the pain perception and range of active ankle motion at the final follow-up.

CONCLUSION

The double nerve transfer technique represented a feasible and safe surgical option. It has been shown to improve function in some patients with neurologic foot drop resulting from a less than 12-month injury of the deep peroneal nerve.

LEVEL OF EVIDENCE

Level IV, therapeutic.

Restoration of Neurological Function Following Peripheral Nerve Trauma

Following peripheral nerve trauma that damages a length of the nerve, recovery of function is generally limited. This is because no material tested for bridging nerve gaps promotes good axon regeneration across the gap under conditions associated with common nerve traumas. While many materials have been tested, sensory nerve grafts remain the clinical “gold standard” technique. This is despite the significant limitations in the conditions under which they restore function. Thus, they induce reliable and good recovery only for patients < 25 years old, when gaps are <2 cm in length, and when repairs are performed <2–3 months post trauma. Repairs performed when these values are larger result in a precipitous decrease in neurological recovery. Further, when patients have more than one parameter larger than these values, there is normally no functional recovery. Clinically, there has been little progress in developing new techniques that increase the level of functional recovery following peripheral nerve injury. This paper examines the efficacies and limitations of sensory nerve grafts and various other techniques used to induce functional neurological recovery, and how these might be improved to induce more extensive functional recovery. It also discusses preliminary data from the clinical application of a novel technique that restores neurological function across long nerve gaps, when repairs are performed at long times post-trauma, and in older patients, even under all three of these conditions. Thus, it appears that function can be restored under conditions where sensory nerve grafts are not effective.

Hydrogel composition and laser micropatterning to regulate sciatic nerve regeneration

Treatment of peripheral nerve injuries has evolved over the past several decades to include the use of sophisticated new materials endowed with trophic and topographical cues that are essential for in vivo nerve fibre regeneration. In this research, we explored the use of an advanced design strategy for peripheral nerve repair, using biological and semi-synthetic hydrogels that enable controlled environmental stimuli to regenerate neurons and glial cells in a rat sciatic nerve resection model. The provisional nerve growth conduits were composed of either natural fibrin or adducts of synthetic polyethylene glycol and fibrinogen or gelatin. A photo-patterning technique was further applied to these 3D hydrogel biomaterials, in the form of laser-ablated microchannels, to provide contact guidance for unidirectional growth following sciatic nerve injury. We tested the regeneration capacity of subcritical nerve gap injuries in rats treated with photo-patterned materials and compared these with injuries treated with unpatterned hydrogels, either stiff or compliant. Among the factors tested were shear modulus, biological composition, and micropatterning of the materials. The microchannel guidance patterns, combined with appropriately matched degradation and stiffness properties of the material, proved most essential for the uniform tissue propagation during the nerve regeneration process.

Fibrin glue as a stabilization strategy in peripheral nerve repair when using porous nerve guidance conduits

Porous conduits provide a protected pathway for nerve regeneration, while still allowing exchange of nutrients and wastes. However, pore sizes >30 µm may permit fibrous tissue infiltration into the conduit, which may impede axonal regeneration. Coating the conduit with Fibrin Glue (FG) is one option for controlling the conduit's porosity. FG is extensively used in clinical peripheral nerve repair, as a tissue sealant, filler and drug-delivery matrix. Here, we compared the performance of FG to an alternative, hyaluronic acid (HA) as a coating for porous conduits, using uncoated porous conduits and reverse autografts as control groups. The uncoated conduit walls had pores with a diameter of 60 to 70 µm that were uniformly covered by either FG or HA coatings. In vitro, FG coatings degraded twice as fast as HA coatings. In vivo studies in a 1 cm rat sciatic nerve model showed FG coating resulted in poor axonal density (993 ± 854 #/mm²), negligible fascicular area (0.03 ± 0.04 mm²), minimal percent wet muscle mass recovery (16 ± 1 in gastrocnemius and 15 ± 5 in tibialis anterior) and G-ratio (0.73 ± 0.01). Histology of FG-coated conduits showed excessive fibrous tissue infiltration inside the lumen, and fibrin capsule formation around the conduit. Although FG has been shown to promote nerve regeneration in non-porous conduits, we found that as a coating for porous conduits in vivo, FG encourages scar tissue infiltration that impedes nerve regeneration. This is a significant finding considering the widespread use of FG in peripheral nerve repair.

Epineurial Window Is More Efficient in Attracting Axons than Simple Coaptation in a Sutureless (Cyanoacrylate-Bound) Model of End-to-Side Nerve Repair in the Rat Upper Limb: Functional and Morphometric Evidences and Review of the Literature

End-to-side nerve coaptation brings regenerating axons from the donor to the recipient nerve. Several techniques have been used to perform coaptation: microsurgical sutures with and without opening a window into the epi(peri)neurial connective tissue; among these, window techniques have been proven more effective in inducing axonal regeneration. The authors developed a sutureless model of end-to-side coaptation in the rat upper limb. In 19 adult Wistar rats, the median and the ulnar nerves of the left arm were approached from the axillary region, the median nerve transected and the proximal stump sutured to the pectoral muscle to prevent regeneration. Animals were then randomly divided in two experimental groups (7 animals each, 5 animals acting as control): Group 1: the distal stump of the transected median nerve was fixed to the ulnar nerve by applying cyanoacrylate solution; Group 2: a small epineurial window was opened into the epineurium of the ulnar nerve, caring to avoid damage to the nerve fibres; the distal stump of the transected median nerve was then fixed to the ulnar nerve by applying cyanoacrylate solution. The grasping test for functional evaluation was repeated every 10-11 weeks starting from week-15, up to the sacrifice (week 36). At week 36, the animals were sacrificed and the regenerated nerves harvested and processed for morphological investigations (high-resolution light microscopy as well as stereological and morphometrical analysis). This study shows that a) cyanoacrylate in end-to-side coaptation produces scarless axon regeneration without toxic effects; b) axonal regeneration and myelination occur even without opening an epineurial window, but c) the window is related to a larger number of regenerating fibres, especially myelinated and mature, and better functional outcomes.

Alignment of the Fibrin Network Within an Autologous Plasma Clot

Autologous plasma clots with longitudinally aligned fibrin fibers could serve as a scaffold for longitudinal axonal regrowth in cases of traumatic peripheral nerve injuries. Three different techniques for assembling longitudinally oriented fibrin fibers during the fibrin polymerization process were investigated as follows: fiber alignment was induced by the application of either a magnetic field or-as a novel approach-electric field or by the induction of orientated flow. Fiber alignment was characterized by scanning electron microscopy analysis followed by image processing using fast Fourier transformation (FFT). Besides FFT output images, area xmin to xmax, as well as full width at half maximum (FWHM) of the FFT graph plot peaks, was calculated to determine the relative degree of fiber alignment. In addition, fluorescently labeled human fibrinogen and mesenchymal stem cells (MSCs) were used to visualize fibrin and cell orientation in aligned and nonaligned plasma clots. Varying degrees of fiber alignment were achieved by the three different methods, with the electric field application producing the highest degree of fiber alignment. The embedded MSCs showed a longitudinal orientation in the electric field-aligned plasma clots. The key feature of this study is the ability to produce autologous plasma clots with aligned fibrin fibers using physical techniques. This orientated internal structure of an autologous biomaterial is promising for distinct therapeutic applications, such as a guiding structure for cell migration and growth dynamics.

Fibrin glue repair leads to enhanced axonal elongation during early peripheral nerve regeneration in an in vivo mouse model

Microsurgical suturing is the gold standard of nerve coaptation. Although literature on the usefulness of fibrin glue as an alternative is becoming increasingly available, it remains contradictory. Furthermore, no data exist on how both repair methods might influence the morphological aspects (arborization; branching) of early peripheral nerve regeneration. We used the sciatic nerve transplantation model in thy-1 yellow fluorescent protein mice (YFP; n = 10). Pieces of nerve (1cm) were grafted from YFP-negative mice (n = 10) into those expressing YFP. We performed microsuture coaptations on one side and used fibrin glue for repair on the contralateral side. Seven days after grafting, the regeneration distance, the percentage of regenerating and arborizing axons, the number of branches per axon, the coaptation failure rate, the gap size at the repair site and the time needed for surgical repair were all investigated. Fibrin glue repair resulted in regenerating axons travelling further into the distal nerve. It also increased the percentage of arborizing axons. No coaptation failure was detected. Gap sizes were comparable in both groups. Fibrin glue significantly reduced surgical repair time. The increase in regeneration distance, even after the short period of time, is in line with the results of others that showed faster axonal regeneration after fibrin glue repair. The increase in arborizing axons could be another explanation for better functional and electrophysiological results after fibrin glue repair. Fibrin glue nerve coaptation seems to be a promising alternative to microsuture repair.

Engineered electrical conduction tract restores conduction in complete heart block: from in vitro to in vivo proof of concept

BACKGROUND

Cardiac electrical conduction delays and blocks cause rhythm disturbances such as complete heart block, which can be fatal. Standard of care relies on electronic devices to artificially restore synchrony. We sought to create a new modality for treating these disorders by engineering electrical conduction tracts designed to propagate electrical impulses.

OBJECTIVES

This study sought to create a new approach for treating cardiac conduction disorders by using engineered electrical conduction tracts (EECTs).

METHODS

Paramagnetic beads were conjugated with an antibody to gamma-sarcoglycan, a cardiomyocyte cell surface antigen, and mixed with freshly isolated neonatal rat ventricular cardiomyocytes. A magnetic field was used to pattern a linear EECT.

RESULTS

In an in vitro model of conduction block, the EECT was patterned so that it connected 2 independently beating neonatal rat ventricular cardiomyocyte monolayers; it achieved coordinated electrical activity, with action potentials propagating from 1 region to the other via EECT. Spiking the EECT with heart-derived stromal cells yielded stable structures with highly reproducible conduction velocities. Transplantation of EECTs in vivo restored atrioventricular conduction in a rat model of complete heart block.

CONCLUSIONS

An EECT can re-establish electrical conduction in the heart. This novel approach could, in principle, be used not only to treat cardiac arrhythmias but also to repair other organs.

Platelet-rich plasma gel in combination with Schwann cells for repair of sciatic nerve injury

Bone marrow mesenchymal stem cells were isolated from New Zealand white rabbits, culture-expanded and differentiated into Schwann cell-like cells. Autologous platelet-rich plasma and Schwann cell-like cells were mixed in suspension at a density of 1 × 10(6) cells/mL, prior to introduction into a poly (lactic-co-glycolic acid) conduit. Fabricated tissue-engineered nerves were implanted into rabbits to bridge 10 mm sciatic nerve defects (platelet-rich plasma group). Controls were established using fibrin as the seeding matrix for Schwann cell-like cells at identical density to construct tissue-engineered nerves (fibrin group). Twelve weeks after implantation, toluidine blue staining and scanning electron microscopy were used to demonstrate an increase in the number of regenerating nerve fibers and thickness of the myelin sheath in the platelet-rich plasma group compared with the fibrin group. Fluoro-gold retrograde labeling revealed that the number of Fluoro-gold-positive neurons in the dorsal root ganglion and the spinal cord anterior horn was greater in the platelet-rich plasma group than in the fibrin group. Electrophysiological examination confirmed that compound muscle action potential and nerve conduction velocity were superior in the platelet-rich plasma group compared with the fibrin group. These results indicate that autologous platelet-rich plasma gel can effectively serve as a seeding matrix for Schwann cell-like cells to construct tissue-engineered nerves to promote peripheral nerve regeneration.

Fibrin glue as the cell-delivery vehicle for mesenchymal stromal cells in regenerative medicine

The use of tissue-engineering techniques such as stem-cell therapy to renew injured tissues is a promising strategy in regenerative medicine. As a cell-delivery vehicle, fibrin glues (FG) facilitate cell attachment, growth and differentiation and, ultimately, tissue formation and organization by its three-dimensional structure. Numerous studies have provided evidence that stromal cells derived from bone marrow (bone marrow stromal cells; BMSC) and adipose tissue (adipose-derived stromal cells; ADSC) contain a population of adult multipotent mesenchymal stromal cells (MSC) and endothelial progenitor cells that can differentiate into several lineages. By combining MSC with FG, the implantation could take advantage of the mutual benefits. Researchers and physicians have pinned their hopes on stem cells for developing novel approaches in regenerative medicine. This review focuses on the therapeutic potential of MSC with FG in bone defect reconstruction, cartilage and tendon injury repair, ligament, heart and nerve regeneration, and, furthermore, wound healing.

Trophic activity derived from bone marrow mononuclear cells increases peripheral nerve regeneration by acting on both neuronal and glial cell populations

A rat model of complete sciatic nerve transection was used to evaluate the effect of bone marrow mononuclear cells (BMMC) transplanted to the injury site immediately after lesion. Rats treated with BMMC had both sensory and motor axons reaching the distal stump earlier compared to untreated animals. In addition, BMMC transplantation reduced cell death in dorsal root ganglia (DRG) compared to control animals. Transplanted BMMC remained in the lesion site for several days but there is no evidence of BMMC differentiation into Schwann cells. However, an increase in the number of Schwann cells, satellite cells and astrocytes was observed in the treated group. Moreover, neutralizing antibodies for nerve growth factor (NGF) (but not for brain-derived neurotrophic factor and ciliary-derived neurotrophic factor) added to the BMMC-conditioned medium reduced neurite growth of sensory and sympathetic neurons in vitro, suggesting that BMMC release NGF, improve regeneration of the sciatic nerve in the adult rat and stimulate Schwann and satellite cell proliferation or a combination of both.

Schwann cell strip for peripheral nerve repair

Many strategies have been investigated to provide an ideal substitute to treat a nerve gap injury. Initially, silicone conduits were used and more recently conduits fabricated from natural materials such as poly-3-hydroxybutyrate (PHB) showed good results but still have their limitations. Surgically, a new concept optimising harvested autologous nerve graft has been introduced as the single fascicle method. It has been shown that a single fascicle repair of nerve grafting is successful. We investigated a new approach using a PHB strip seeded with Schwann cells to mimic a small nerve fascicle. Schwann cells were attached to the PHB strip using diluted fibrin glue and used to bridge a 10-mm sciatic nerve gap in rats. Comparison was made with a group using conventional PHB conduit tubes filled with Schwann cells and fibrin glue. After 2 weeks, the nerve samples were harvested and investigated for axonal and Schwann cell markers. PGP9.5 immunohistochemistry showed a superior nerve regeneration distance in the PHB strip group versus the PHB tube group (> 10 mm, crossed versus 3.17+/- 0.32 mm respectively, P<0.05) as well as superior Schwann cell intrusion (S100 staining) from proximal (> 10 mm, crossed versus 3.40+/- 0.36 mm, P<0.01) and distal (> 10 mm, crossed versus 2.91+/- 0.31 mm, P<0.001) ends. These findings suggest a significant advantage of a strip in rapidly connecting a nerve gap lesion and imply that single fascicle nerve grafting is advantageous for nerve repair in rats.

Fibrin matrix for suspension of regenerative cells in an artificial nerve conduit

Peripheral nerve injury presents with specific problems of neuronal reconstructions, and from a clinical viewpoint a tissue engineering approach would facilitate the process of repair and regeneration. We have previously used artificial nerve conduits made from bioresorbable poly-3-hydroxybutyrate (PHB) in order to refine the ways in which peripheral nerves are repaired and reconnected to the target muscles and skin. The addition of Schwann cells (SC) or differentiated mesenchymal stem cells (dMSC) to the conduits enhances regeneration. In this study, we have used a matrix based on fibrin (Tisseel) to fill optimally the nerve-conduits with cells. In vitro analysis showed that both SC and MSC adhered significantly better to PHB in the presence of fibrin and cells continued to maintain their differentiated state. Cells were more optimally distributed throughout the conduit when seeded in fibrin than by delivery in growth medium alone. Transplantation of the nerve conduits in vivo showed that cells in combination with fibrin matrix significantly increased nerve regeneration distance (using PGP9.5 and S100 distal and proximal immunohistochemistry) when compared with empty PHB conduits. This study shows the beneficial combinatory effect of an optimised matrix, cells and conduit material as a step towards bridging nerve gaps which should ultimately lead to improved functional recovery following nerve injury.

Hyperbaric oxygenation in peripheral nerve repair and regeneration

Peripheral nerves are essential connections between the central nervous system and muscles, autonomic structures and sensory organs. Their injury is one of the major causes for severe and longstanding impairment in limb function. Acute peripheral nerve lesion has an important inflammatory component and is considered as ischemia-reperfusion (IR) injury. Surgical repair has been the standard of care in peripheral nerve lesion. It has reached optimal technical development but the end results still remain unpredictable and complete functional recovery is rare. Nevertheless, nerve repair is not primarily a mechanical problem and microsurgery is not the only key to success. Lately, there have been efforts to develop alternatives to nerve graft. Work has been carried out in basal lamina scaffolds, biologic and non-biologic structures in combination with neurotrophic factors and/or Schwann cells, tissues, immunosuppressive agents, growth factors, cell transplantation, principles of artificial sensory function, gene technology, gangliosides, implantation of microchips, hormones, electromagnetic fields and hyperbaric oxygenation (HBO). HBO appears to be a beneficial adjunctive treatment for surgical repair in the acute peripheral nerve lesion, when used at lower pressures and in a timely fashion (<6 hours).

Usefulness of autologous cartilage and fibrin glue for the prevention of septal perforation during septal surgery: a preliminary report

OBJECTIVES

Septal surgery is one of the most common causes of nasal septal perforation. In cases in which a septal mucosal defect at the corresponding area has occurred, autologous cartilage is usually inserted between the injured mucosal flaps. In addition, we applied fibrin glue to the margins of injured mucosal surface to fix the inserted cartilage and to promote mucosal regeneration. The aim of this study was to evaluate the efficacy of this method in the prevention of nasal septal perforation.

STUDY DESIGN

Retrospective analysis of medical records.

METHODS

A total of 463 septal surgeries were performed between March 2003 and August 2005. Septal mucosal defect at the corresponding area occurred in 34 patients. In group 1 (23 patients), septal or auricular cartilage was inserted between the injured mucosal flaps. In group 2 (11 patients), septal or auricular cartilage was inserted, and fibrin glue was applied on the mucosal margins of cartilage insertion site. We compared the perforation rate between the two groups.

RESULTS

In group 1, nasal septal perforation occurred 8 of 23 (34.8%) patients, and in group 2, 1 of 11 (9.1%) patients experienced perforation. Although the occurrence rate of perforation was significantly lower in group 2, statistical significance between the two groups could not be established because of the small number of patients who experienced septal perforation.

CONCLUSION

The application of fibrin glue at the bilaterally injured mucosal surface after cartilage insertion is thought to be very useful as a preventive measure of nasal septal perforation. We report these results as preliminary data for further study to determine the usefulness of fibrin glue in the prevention of nasal septal perforation.