Inside-out Vein Graft Research Articles

Comparative study between standard and inside-out vein graft techniques on sciatic nerve repair of rats. Muscular and functional analysis.

To compare the functional result of standart vein grafts and inside-out vein graft technique on sciatic nerve repair. We used 24 male Wistar rats divided into 4 groups: control group (CG), standard vein graft group (SVG), Inside-out vein graft group (IOVG) and denervated Group (DG). SVG, IOVG and DG underwent total section of the sciatic nerve, SVG and IOVG however underwent nerve repair surgery using a graft with normal jugular vein and inside-out jugular vein, respectively. Histological analysis of the soleus and Extensor Digitorum Longus (EDL), and Sciatic Functional Index were used to compare the results after 6 weeks. Both grafts acted favorably in muscle recovery and improved functionality; They were similar in all parameters, however, in more points SVG achieved similar to the CG, in the other hand IOVG more times was similar to DG. Fact that makes the graft with normal vein the most viable option between the two options. Both types of grafts acted beneficially wherein the graft normal vein has proved to be the best option.

Flunarizine, Calcium Channel Blocker, Locally Improves Functional Recovery of the Transected Sciatic Nerve After Bridging With Inside-Out Vein Graft

Flunarizine, Calcium Channel Blocker, Locally Improves Functional Recovery of the Transected Sciatic Nerve After Bridging With Inside-Out Vein Graft

Peripheral Nerve Regeneration using Silicone Rubber Chamber Combined by Local Administration of Cyclosporin a in Streptozotocin Induced Diabetic Rats

Introduction Surgical therapy in patients with peripheral nerve injuries has not presented changes over the last decades due to the use of autologous grafts, development of intraoperative magnification, and proven deleterious effects of tension at neural repair site and despite all the advancements achieved, functional repair results are still imperfect [1 1. Tuma JP, Ferreira MC, Nakamoto HA, Milcheski DA, Cheroto FA (2008) Influence of immunosupression on nerve regeneration using allografts: an experimental study on rats. Acta Ortop Bras 16: 41-44. ]. In case of significant damage to nerve tissue, severely-damaged nerves do not spontaneously restore their function and their continuity has to be first reestablished by microsurgical intervention such as suture or interposition of a graft [2 2. Pfister LA, Papaloizos M, Merkle HP, Gander B (2007) Nerve conduits and growth factor delivery in peripheral nerve repair. J Peripher Nerv Syst 12: 65-82. ,3 3. Schmidt CE, Leach JB (2003) Neural tissue engineering: strategies for repair and regeneration. Annu Rev Biomed Eng 5: 293-347. ]. A widely accepted method used by most surgeons involves bridging the defect with an autologous donor nerve. However, it has disadvantages of sacrificing functional nerves [4 4. Mohammadi R, Azizi S, Delirezh N, Hobbenaghi R, Amini K (2012) Transplantation of uncultured omental adipose-derived stromal vascular fraction improves sciatic nerve regeneration and functional recovery through inside-out vein graft in rats. J Trauma 72: 390-396. ].

Outcome Following Lingual Nerve Repair With Vein Graft Cuff: A Preliminary Report

The object of this study was to assess the effects of an inside-out vein graft as a cuff after direct suture on human lingual nerve regeneration and recovery after iatrogenic lingual nerve injury. Ten patients with unilateral lingual nerve anesthesia as a complication of iatrogenic injury after third molar extraction underwent microneurosurgical procedures for the injured lingual nerve under general anesthesia. The patients were randomized into 2 groups. In group A, after removing the neuromas and peripheral scars surrounding the torn nerves, the 2 nerve ends were sutured without tension. In group B, after the same procedure, including the same suturing procedure, an inside-out vein graft was placed as a cuff after the direct suture. Each group was followed at least once every 6 months for 1 year after the procedure. Postoperative outcomes were evaluated using the Pogrel criteria, the Sunderland grade, and the British Medical Research Council Scale (MRCS). There were no particular differences between groups A and B at 6 and 12 months after the operation. However, based on the MRCS criteria, there was a clearly better result in group B than in group A at 6 and 12 months after the operation, and the recovery of gustatory sensation tended to be better in group B than in group A 1 year after the operation. This inside-out vein graft as a cuff after direct suturing may facilitate faster lingual nerve regeneration than the traditional direct suture approach. The inside-out vein graft as a cuff may provide the advantages of preventing axonal escape at the suture lines, minimizing nerve entrapment, and preventing neuroma formation in the space between the sutured nerves.

An inside-out vein graft filled with platelet-rich plasma for repair of a short sciatic nerve defect in rats.

Platelet-rich plasma containing various growth factors can promote nerve regeneration. An inside-out vein graft can substitute nerve autograft to repair short nerve defects. It is hypothesized that an inside-out vein graft filled with platelet-rich plasma shows better effects in the repair of short sciatic nerve defects. In this study, an inside-out vein autograft filled with platelet-rich plasma was used to bridge a 10 mm-long sciatic nerve defect in rats. The sciatic nerve function of rats with an inside-out vein autograft filled with platelet-rich plasma was better improved than that of rats with a simple inside-out vein autograft. At 6 and 8 weeks, the sciatic nerve function of rats with an inside-out vein autograft filled with platelet-rich plasma was better than that of rats undergoing nerve autografting. Compared with the sciatic nerve repaired with a simple inside-out vein autograft, the number of myelinated axons was higher, axon diameter and myelin sheath were greater in the sciatic nerve repaired with an inside-out vein autograft filled with platelet-rich plasma and they were similar to those in the sciatic nerve repaired with nerve autograft. These findings suggest that an inside-out vein graft filled with platelet-rich plasma can substitute nerve autograft to repair short sciatic nerve defects.

Inside-out Vein Graft vs Autogenous Nerve Graft in Promoting Axonal Regeneration: An Experimental Study in a Rat Model

Background: An experimental study was done to compare the efficacy of inside-out vein graft versus autogenous nerve graft as nerve conduit in promoting axonal regeneration in a rat model. Methods: The study used 16 Spraque-Dawley rats randomly divided into two groups: the inside-out vein graft group and control group (autognous nerve graft). The outcomes measured were histomorphology (axon number and diameter), muscle twitch response (amplitude) and the walking track analysis at 2, 4 6 and 8 weeks. Results: The inverted vein graft and control groups showed similar axon diameter (P=0.76), and axon number (P=0.85), weeks and similar muscle twitch responses (P=0.87) after eight weeks. The walking track analysis showed no significant difference between the two groups at eight weeks. Conclusion: The study showed that the inside-out vein graft group had similar motor recovery as compared to control group based on the muscle twitch analysis and walking track analysis in a rat model. In terms of histomorphometric analysis, the two groups were similar in terms of axon diameter and axon count. Key words: nerve regeneration, nerve repair, muscle contraction

Betamethasone-Enhanced Vein Graft Conduit Accelerates Functional Recovery in the Rat Sciatic Nerve Gap

The objective of the study was to assess the effect of topically administered betamethasone on peripheral nerve regeneration and functional recovery after sciatic nerve transection in the rat. Forty-five healthy male white Wistar rats were divided into 3 experimental groups (n = 15), randomly. In the treatment group, a 10-mm sciatic nerve defect was bridged by use of an inside-out vein graft filled with 10 μL betamethasone (0.1 mg/kg) (IOVG/BETA group). In the control group, the vein was filled with phosphate-buffered saline solution alone (IOVG group). In the sham surgery group, the sciatic nerve was exposed with no further deleterious manipulations (SHAM group). Each group was subdivided into 3 subgroups of 5 animals each, and the regenerated nerve fibers were studied 4, 8, and 12 weeks after surgery. Functional study confirmed faster recovery of regenerated axons in the IOVG/BETA group than in the IOVG group (P < .05). Gastrocnemius muscle mass in the IOVG/BETA group was found to be significantly greater than that in the IOVG group (P < .05). Morphometric indices of the regenerated fibers showed that the number and diameter of the myelinated fibers were significantly higher in the IOVG/BETA group than in the control group (P < .05). By use of immunohistochemistry, the location of reactions to S-100 in IOVG/BETA was clearly more positive than that in the IOVG group. When loaded in a vein graft, betamethasone resulted in improvement of functional recovery and quantitative morphometric indices of sciatic nerve. Topical application of this readily available agent offers the benefit of cost savings, as well as avoiding the complications associated with systemic administration.

Effects of topically administered FK506 on sciatic nerve regeneration and reinnervation after vein graft repair of short nerve gaps

Despite the development of various nerve coaptation materials and techniques, achievement of desired functional peripheral nerve regeneration is still inadequate, and repair of peripheral nerve injuries is still one of the most challenging tasks and concerns in neurosurgery. The effect of an FK506-loaded vein graft as an in situ delivery system for FK506 in bridging the defects was studied using a rat sciatic nerve regeneration model. A 10-mm sciatic nerve defect was bridged using an inside-out vein graft (IOVG) filled with 10 μl of a carrier-drug dilution (10 ng/ml FK506) in the IOVG/FK506 group. In the IOVG control group, the vein was filled with the same volume of carrier dilution alone. The regenerated fibers were studied 4, 8, and 12 weeks after surgery. Functional study confirmed faster recovery of the regenerated axons in the IOVG/FK506 group than in the IOVG group (p < 0.05). There was a statistically significant difference between the mean gastrocnemius muscle weight ratios of the IOVG/FK506 and IOVG control groups (p < 0.05). Morphometric indices of regenerated fibers showed that the number and diameter of the myelinated fibers were significantly higher in the IOVG/FK506 group than in the IOVG control group. Immunohistochemical analysis showed more positive immunoreactivity to S100 protein in the IOVG/FK506 group than in the IOVG control group. When loaded in a vein graft, FK506 resulted in improvement of functional recovery and quantitative morphometric indices of sciatic nerve. Topical application of this readily available agent offers the benefit of cost savings as well as avoiding the complications associated with systemic administration.

Transplantation of uncultured omental adipose-derived stromal vascular fraction improves sciatic nerve regeneration and functional recovery through inside-out vein graft in rats

Despite presence of various nerve coaptation materials and techniques, achievement of desired functional peripheral nerve regeneration is still inadequate. Effects of transplantation of uncultured and uncharacterized stromal vascular fraction (SVF) from omental adipose tissue on peripheral nerve regeneration were studied using a rat sciatic nerve transection model. A 10-mm sciatic nerve defect was bridged using an inside-out vein graft (IOVG) filled with SVF. In control group, the vein was filled with phosphate-buffered saline alone. The regenerated nerve fibers were studied 4 weeks, 8 weeks, and 12 weeks after surgery. In sham-operated group, the sciatic nerve was only exposed and manipulated. Functional study confirmed faster recovery of regenerated axons in IOVG/SVF than in IOVG group (p < 0.05). Gastrocnemius muscle mass in IOVG/SVF is found to be significantly more than that in IOVG group. Morphometric indices of the regenerated fibers showed that the number and diameter of the myelinated fibers were significantly higher in IOVG/SVF than in control group.In immunohistochemistry, location of reactions to S-100 in IOVG/SVF was clearly more positive than that in IOVG group. SVF could be considered as a readily accessible source of stromal cells that improve functional recovery of sciatic nerve because of reduction in the interval from tissue collection until cell injection and simplicity of laboratory procedure, especially where atraumatic injury is dealt with.

Transplantation of undifferentiated bone marrow stromal cells improves sciatic nerve regeneration and functional recovery through inside-out vein graft in rats

To study the effect of undifferentiated bone marrow stromal cells (BMSCs) on peripheral nerve regeneration using a rat sciatic nerve regeneration model. In recent years, cell transplantation has become the focus of attention, and reliable outcomes have been achieved in regeneration of the sciatic nerve. Materials and methods: A 10-mm sciatic nerve defect was bridged using an inside-out vein graft (IOVG) filled with undifferentiated BMSCs (2 × 107 cells/mL). In the control group, the vein was filled with phosphate buffered saline alone. The regenerated fibers were studied 4, 8, and 12 weeks after surgery. Assessment of nerve regeneration was based on functional (walking track analysis), histomorphometric, and immunohistochemical (Schwann cell detection by S-100 expression) criteria. Results: The functional study confirmed significant recovery of regenerated axons in the IOVG/BMSC group (P < 0.05). Quantitative morphometric analyses of regenerated fibers showed that the number and diameter of myelinated fibers in the IOVG/BMSC group were significantly higher than in the control group (P < 0.05). Conclusion: This study demonstrates the potential of using undifferentiated BMSCs in peripheral nerve regeneration without limitations of donor-site morbidity associated with isolation of Schwann cells. It also reduces costs due to the simplicity of laboratory procedures compared to those for differentiated BMSCs and the reduction in the interval from tissue collection until cell injection.

The use of undifferentiated bone marrow stromal cells for sciatic nerve regeneration in rats

In recent years, cell transplantation has become a focus of attention and reliable outcomes have been achieved in regeneration of the sciatic nerve. The effect of undifferentiated bone marrow stromal cells (BMSCs) on peripheral nerve regeneration was studied using a rat sciatic nerve regeneration model. A 10-mm sciatic nerve defect was bridged using an inside-out vein graft (IOVG) filled with undifferentiated BMSCs (2×107cells/ml). In the control group, the vein was filled with phosphate buffer saline alone. The regenerated fibres were studied 4, 8 and 12 weeks after surgery. Assessment of nerve regeneration was based on functional (walking track analysis), histomorphometric and immuohistochemical (Schwann cell detection by S100 expression) criteria. The functional study confirmed significant recovery of regenerated axons in the IOVG/BMSC group (P<0.05). Quantitative morphometric analyses of regenerated fibres showed the number and diameter of myelinated fibres in the IOVG/BMSC group were significantly higher than in the control group (P<0.05). This demonstrates the potential for using undifferentiated BMSCs in peripheral nerve regeneration without the limitations of donor-site morbidity associated with isolation of Schwann cells. It also reduces costs because the interval between tissue collection and cell injection is reduced and the laboratory procedures are simpler compared to undifferentiated BMSCs.

Clinical application of inside‐out vein grafts for the treatment of sensory nerve segmental defect

The gold standard for the treatment of segmental nerve defect is an autogenous nerve graft. However, donor site morbidity is an inevitable complication. We substituted an autogenous nerve graft with an inside-out vein graft for the treatment of segmental sensory nerve defect and the clinical results were evaluated retrospectively. Eleven patients of sensory nerve defects have undertaken inside-out vein grafts for the recovery of sensation. The involved nerves were digital nerves in three cases, peroneal nerves in two cases, saphenous nerve in two cases, and superficial radial nerves in four cases. The average length of defects was 2.71 cm (1-6 cm). Donor veins were harvested 4 mm longer than nerve defects and everted to promote nerve regeneration. Patients' objective satisfactions and two-point discriminations were determined, the Semmes-Weinstein monofilament test was performed, and British Medical Council sensory functional scores were evaluated. Sensory functional scores recovered to over S3 in all cases. No donor site morbidity was caused by vein harvesting, and all patients achieved satisfactory results with protective sensation at involved sites. The inside-out vein graft offers a good surgical alternative to an autogenous nerve graft for the reconstruction of sensory nerve defects without donor site morbidity.

Functional recovery of sciatic nerve through inside-out vein graft in rats

Objective Present study aimed at further comprehensive functional, histomorphometrical and immunohistochemical assessment of peripheral nerve regeneration using rat sciatic nerve transection model. Methods The 10-mm rat sciatic nerve gap was created in rats. In control group nerve stumps were sutured to adjacent muscle and in treatment group the gap was bridged using an inside-out vein graft. In sham-operated group the nerve was manipulated and left intact. All animals underwent walking track analysis test 4, 8, and 12 weeks after surgery. Subsequently, muscle mass measurement was performed to assess reenervation, histological examination to observe the sciatic nerve regeneration morphologically and Immunohistochemistry to detect Schwann cells using anti S-100. Results were analyzed using a factorial ANOVA with two between-subjects factors. Bonferroni test for pairwise comparisons was used to examine the effect of treatments. Results Functional analysis of myelinated nerve fibers showed that nerve function improved significantly in the time course in treatment group. However, quantitative morphometrical analysis of myelinated nerve fibers showed that there was no significant difference between 8 and 12 weeks in treatment group. Muscle weight ratio was bigger and weight loss of the gastrocnemius muscle was ameliorated by inside-out vein grafting. The position of positive immunohistochemical reactions further implied that regenerated axons and Schwann cell-like cells existed after vein grafting was performed, and was accompanied by the process of myelination and structural recovery of regenerated nerves. Conclusion Functional analysis of peripheral nerve repair is far more reliable than quantitative morphometrical analysis

Comparison of the Nerve Regenerating Effect of Inside-out Vein Grafts, Muscle-filled Inside-out Vein Grafts, and Fat-interposed Inside-out Vein Grafts in Rats

Purpose: We wanted to compare the nerve regeneration of inside-out vein grafts, muscle-filled inside-out vein grafts and fat-interposed inside-out vein grafts to repair the 10 mm sciatic nerve defects in rats. Materials and Methods: We performed inside-out vein grafts, muscle-filled inside-out vein grafts and fat-interposed inside-out vein grafts to repair the 10 mm sciatic nerve defects in 45 rats. Histological examinations (the numbers and diameters of myelinated nerve fibers), electrophysiologic testing (Compound Muscle Action Potential (CMAP) and Nerve Conduction Velocity (NCV)) examinations were performed 3 months after surgery. Results: Quantitative analysis of myelinated nerve fibers showed that total number of nerve fibers was significantly greater in group 1 or 3 than that in group 2. There were statistical differences in the three groups for the fiber diameters of the myelinated fibers. Electrophysiologic examination showed that both CMAP and NCV were significantly greater in group 3 than that in group 2 and there was no statistical difference between in groups 1 and 3. Conclusion: This study shows that fat-interposed inside-out vein grafts have excellent axonal regeneration as compared to that of inside-out vein grafts or muscle-filled inside-out vein grafts to repair 10 mm sciatic nerve defects in rat. Therefore fat-interposed inside-out vein grafts are an effective method to accelerate the early axonal regeneration for repairing nerve defects.

Autogenous standard versus inside-out vein graft to repair facial nerve in rabbits

To evaluate autogenous vein grafts and inside-out vein grafts as conduits for the defects repair in the rabbit facial nerves. The 10 mm segments of buccal division of facial nerve were transected for 48 rabbits in this study. Then the gaps were immediately repaired by autogenous vein grafts or inside-out vein grafts in different groups. All the animals underwent the whisker movement test and electrophysiologic test during the following 16 weeks at different time points postoperatively. Subsequently, the histological examination was performed to observe the facial nerve regeneration morphologically. At 8 weeks after operation, the facial nerve regeneration has significant difference between the experimental group and the control group in electrophysiologic test and histological observation. However, at the end of this study, 16 weeks after operation, there was no significant difference between inside-out vein grafts and standard vein grafts in enhancing peripheral nerve regeneration. This study suggest that both kinds of vein grafts play positive roles in facial nerve regeneration after being repaired immediately, but the autogenous inside-out vein grafts might accelerate and facilitate axonal regeneration as compared with control.

A method of invaginating the facial vein for inferior alveolar nerve repair

Autogenous vein grafting has been previously described as a successful method of bridging defects in the inferior alveolar and peripheral nerves.1,2 Neuronal elements are able to grow along the lumen of the vein graft. However, animal studies have shown that the contact between the endothelial cells of the transplanted venous segment and nervous tissue initiates the development of connective tissue and may cause constriction of the nerve. This process may begin before axons can regenerate and compromise full regeneration of the nerve. Collagen and laminin have been shown to promote nerve regeneration. The vein wall consists of 3 layers: the endothelial layer containing a laminin-rich basal lamina, the media containing a thin muscle layer that is also rich in laminin, and the adventitia that is rich in collagen. Turning the vein inside-out such that the adventitia forms the lumen of the conduit has been shown in animal studies to expose the regenerating axons directly to the collagen-rich adventitia, allowing permeability of external factors and trophic and neurite-promoting factors that line the adventitia.3,4 Invaginated vein grafts have been reported to significantly increase regenerative axonal counts, with greater extent of early myelination and richer blood supply compared with conventional nerve grafting and standard vein grafts.4-6 In electromyographic studies on inside-out vein grafts, Wang et al5 showed faster conduction velocities compared with nerve grafting, the gold standard of peripheral nerve gap repair. Therefore, in theory, inverting the vein may release the full potential growth of the nerve fascicles anastomosed to the vessel. The following is a method for the inversion of small-caliber veins (eg, the facial vein) that we have successfully used. An 18-gauge angiocatheter with saline syringe is

Inside‐out vein graft and inside‐out artery graft in rat sciatic nerve repair

Although veins and arteries present similar wall structures, there are differences which may be relevant in peripheral nerve reconstruction. Inside-out vein grafts (IOVG) have been satisfactorily used to repair both motor and sensitive nerves. However, the inside-out artery graft (IOAG) is a new technique and not fully investigated. Our study presents comparative morphological data on nerve regeneration achieved with IOVG and IOAG in the repair of Wistar rat sciatic nerves. Jugular veins and aorta arteries were harvested from donor animals and used "inside-out" to bridge a 10-mm gap. Animals were sacrificed at 10 weeks to evaluate nerve regeneration. Both techniques presented great variability in nervous tissue, though some animals showed satisfactory results. Different intensities of scarring processes might have interfered with nerve regeneration. Although IOVG and IOAG techniques showed similar morphometric results, in general, IOVG presented a closer-to-normal nerve organization than IOAG.

Experimental Study of Nerve Regeneration by Inside-in and Inside-out Vein Graft in the Nerve Defect of Rat

Experimental Study of Nerve Regeneration by Inside-in and Inside-out Vein Graft in the Nerve Defect of Rat

Inside‐outl vein graft repair compared with nerve grafting for nerve regeneration in rats

The inside-out vein graft is a vein conduit pulled through itself to invert the normal orientation and place the adventitial layer within the lumen of the conduit. Our study compares regeneration of peripheral nerves in the rat through two conduits: inside-out graft of the jugular vein and autogenous nerve graft. In 10 rats, the right jugular vein was harvested, turned inside out, and used to bridge a 10 mm defect created in the right sciatic nerve. The 10 mm nerve segment from the right was then used as a standard nerve graft to bridge a 10 mm gap created in the left sciatic nerve. Rats were sacrificed at 8 and 12 weeks. Regeneration on the inside-out vein graft side showed superior functional results (faster conduction velocities) and improved histological results (greater axon counts) compared with the nerve grafted side. We feel the adventitial surface of the wall of the vein promotes nerve regeneration by providing an environment rich with collagen, laminin, and Schwann cells and promotes increased vascularization of the new nerve.