Cyanoacrylate glue versus suture in peripheral nerve reanastomosis

Tensile strength of adhesives in peripheral nerve anastomoses: an in vitro biomechanical evaluation of four different neurorrhaphies

BACKGROUND

The fundamental prerequisite for prognostically favorable postoperative results of peripheral nerve repair is stable neurorrhaphy without interruption and gap formation.

METHODS

This study evaluates 60 neurorrhaphies on femoral chicken nerves in terms of the procedure and the biomechanical properties. Sutured neurorrhaphies (n = 15) served as control and three sutureless adhesive-based nerve repair techniques: Fibrin glue (n = 15), Histoacryl glue (n = 15), and the novel polyurethane adhesive VIVO (n = 15). Tensile and elongation tests of neurorrhaphies were performed on a tensile testing machine at a displacement rate of 20 mm/min until failure. The maximum tensile force and elongation were recorded.

RESULTS

All adhesive-based neurorrhaphies were significant faster in preparation compared to sutured anastomoses (p < 0.001). Neurorrhaphies by sutured (102.8 [cN]; p < 0.001), Histoacryl (91.5 [cN]; p < 0.001) and VIVO (45.47 [cN]; p < 0.05) withstood significant higher longitudinal tensile forces compared to fibrin glue (10.55 [cN]). VIVO, with △L/L0 of 6.96 [%], showed significantly higher elongation (p < 0.001) compared to neurorrhaphy using fibrin glue.

CONCLUSION

Within the limitations of an in vitro study the adhesive-based neurorrhaphy technique with VIVO and Histoacryl have the biomechanical potential to offer alternatives to sutured neuroanastomosis because of their stability, and faster handling. Further in vivo studies are required to evaluate functional outcomes and confirm safety.

Efficacy of Silicone Conduit in the Rat Sciatic Nerve Repair Model: Journey of a Thousand Miles

Background

A lot of options have been tried for bridging the two ends of the injured nerves. Researchers have used decellularized nerve grafts, artificial materials and even nerve growth factors to augment functional recovery. These materials are either costly or inaccessible in developing world.

Objective

The study aimed to evaluate the efficacy of the silicone conduit in a rat sciatic nerve injury model.

Materials and Methods

24 healthy Sprague-Dawley (SD) rats (250-300 grams; 8-10 weeks) were used and right sciatic nerve was exposed; transected and re-anastomosed by two different methods in 16 rats. In control group, n = 8 (Group I) the sciatic nerve was untouched; Group II (reverse nerve anastomosis, n = 8): 1-centimeter of nerve was cut and re-anastomosed by using 10-0 monofilament suture; Group III (silicone conduit, n = 8) 1-centimeter nerve segment was cut, replaced by silicone conduit and supplemented by fibrin glue]. Evaluation of nerve recovery was done functionally (pain threshold and sciatic functional index) over 3 months and histologically and electron microscopically.

Results

Functional results showed a trend of clinical improvement in Group III and II but recovery was poor and never reached up to normal. Histopathological and electron microscopic results showed an incomplete axonal regeneration in Groups II and III. Psychological analyses showed that no outwards signs of stress were present and none of the rats showed paw biting and teeth chattering.

Conclusion

The silicone conduit graft may be an economical and effective alternative to presently available interposition grafts, however for short segments only.

Fibrin Glue and Its Alternatives in Peripheral Nerve Repair

Over the past century, many advancements have been made in peripheral nerve repair, yet these reconstructions still remain a challenge. Although sutures have historically been used for neurorrhaphy, they sometimes fail to provide optimal outcomes. As a result, multiple adhesive compounds are currently being investigated for their efficacy in nerve repair. Recently, fibrin glue has shown utility in peripheral nerve repair, and the body of evidence supporting its use continues to grow. Fibrin glue has been shown to reduce inflammation, improve axonal regeneration, and provide excellent functional results. This alternative to traditional suture neurorrhaphy could potentially improve outcomes of peripheral nerve reconstruction.

Pain perception following epithelialized gingival graft harvesting: a randomized clinical trial

OBJECTIVES

The aim of this study was to compare the effects of a hemostatic collagen sponge and a collagen sponge sealed with a bio-adhesive material on the palatal donor sites with the purpose of minimizing postoperative pain after epithelialized gingival graft (EGG) harvesting.

MATERIAL AND METHODS

The present study consisted of 44 EGGs harvested in 44 patients. In the control group, a hemostatic collagen sponge was applied over the palatal wound, while the test group was treated with additional cyanoacrylate. Patients were observed for 14 days, evaluating the pain level by using the visual analogic scale. The consumption of analgesic during the postoperative period, the willingness for retreatment and the characteristic of the graft were also analyzed.

RESULTS

Statistically significant differences in pain perception were found between test and control groups in each of the studied days (p < 0.01). Analgesic consumption was lower in the test group (p < 0.01). Graft width < 14 mm was found to be associated with lower discomfort (p < 0.01).

CONCLUSIONS

Adding an additional layer of cyanoacrylate over a hemostatic collagen sponge on the palatal wound following EGG harvesting was found to be successful in minimizing the postoperative discomfort and the need for analgesics.

CLINICAL RELEVANCE

Postoperative pain after palatal tissue harvesting can be successfully minimized if the donor site open wound is protected with an external layer of cyanoacrylate over a collagen sponge.

A novel chronic nerve compression model in the rat

Current animal models of chronic peripheral nerve compression are mainly silicone tube models. However, the cross section of the rat sciatic nerve is not a perfect circle, and there are differences in the diameter of the sciatic nerve due to individual differences. The use of a silicone tube with a uniform internal diameter may not provide a reliable and consistent model. We have established a chronic sciatic nerve compression model that can induce demyelination of the sciatic nerve and lead to atrophy of skeletal muscle. In 3-week-old pups and adult rats, the sciatic nerve of the right hind limb was exposed, and a piece of surgical latex glove was gently placed under the nerve. N-butyl-cyanoacrylate was then placed over the nerve, and after it had set, another piece of glove latex was placed on top of the target area and allowed to adhere to the first piece to form a sandwich-like complex. Thus, a chronic sciatic nerve compression model was produced. Control pups with latex or N-butyl-cyanoacrylate were also prepared. Functional changes to nerves were assessed using the hot plate test and electromyography. Immunofluorescence and electron microscopy analyses of the nerves were performed to quantify the degree of neuropathological change. Masson staining was conducted to assess the degree of fibrosis in the gastrocnemius and intrinsic paw muscles. The pup group rats subjected to nerve compression displayed thermal hypoesthesia and a gradual decrease in nerve conduction velocity at 2 weeks after surgery. Neuropathological studies demonstrated that the model caused nerve demyelination and axonal irregularities and triggered collagen deposition in the epineurium and perineurium of the affected nerve at 8 weeks after surgery. The degree of fibrosis in the gastrocnemius and intrinsic paw muscles was significantly increased at 20 weeks after surgery. In conclusion, our novel model can reproduce the functional and histological changes of chronic nerve compression injury that occurs in humans and it will be a useful new tool for investigating the mechanisms underlying chronic nerve compression.

Sciatic nerve repair using adhesive bonding and a modified conduit

When repairing nerves with adhesives, most researchers place glue directly on the nerve stumps, but this method does not fix the nerve ends well and allows glue to easily invade the nerve ends. In this study, we established a rat model of completely transected sciatic nerve injury and repaired it using a modified 1 cm-length conduit with inner diameter of 1.5 mm. Each end of the cylindrical conduit contains a short linear channel, while the enclosed central tube protects the nerve ends well. Nerves were repaired with 2-octyl-cyanoacrylate and suture, which complement the function of the modified conduit. The results demonstrated that for the same conduit, the average operation time using the adhesive method was much shorter than with the suture method. No significant differences were found between the two groups in sciatic function index, motor evoked potential latency, motor evoked potential amplitude, muscular recovery rate, number of medullated nerve fibers, axon diameter, or medullary sheath thickness. Thus, the adhesive method for repairing nerves using a modified conduit is feasible and effective, and reduces the operation time while providing an equivalent repair effect.

Non-suture technique for rabbit oviduct anastomosis with 2-octyl cyanoacrylate: a histopathologic and biomechanical analysis

AIM

The aim of this study was to investigate histological and biomechanical properties of oviduct anastomosis with 2-octyl cyanoacrylate (OCA) in the rabbit.

MATERIAL AND METHODS

Sixty female rabbits were randomly divided equally into three groups: A (control), B (traditional catgut suture), and C (non-suture technique using OCA). After suture or OCA anastomosis, gross examination (adhesion formation) and histopathology (hematoxylin-eosin), ultrastructure (transmission electron microscopy), and biomechanics (bursting pressure) on para-anastomotic site were investigated on oviduct taken at 1 (A1, B1, C1) and 4 (A2, B2, C2) weeks, respectively.

RESULTS

Adhesion score in group B was more severe than that in groups A and C at 1 and 4 weeks. Histopathology showed that acute endosalpingitis in group B was the most intense at 1 week, followed by significantly more tissue stimulation induced by catgut and foreign-body giant cells in group B than in group C at 4 weeks. Ultrastructural damage of ciliated cells was reversed partly (B2) and completely (C2) at 4 weeks. Bursting pressure in C1 was weaker than that in B1, followed by no significant difference at 4 weeks.

CONCLUSION

Non-suture using OCA for oviduct anastomosis can be accepted as a new-perspective technique.

Retrospective analysis of sutureless skin closure in cleft lip repair

The technique of approximating tissues resulting in minimal amount of scar usually requires skillful suturing techniques by the surgeons, especially in cleft lip repair. Increased awareness and demand for aesthetic surgical correction with quality in tissue closure has led to the invention of new materials and techniques. Amcrylate (iso amyl 2-cyanoacrylate) is retrospectively evaluated as tissue glue in cleft lip repair, and the results are compared with skin closure by 6-0 Prolene. A retrospective analysis of 60 patients with unilateral or bilateral cleft lip repair was carried out to compare the results of skin closure with Amcrylate and 6-0 Prolene. Patients were randomly divided into 2 groups, each group containing 30, and the study was designed to evaluate the quality of scars after the use of Amcrylate tissue adhesive to close the skin during cleft lip repair and its advantages over sutures (6-0 Prolene). Both groups were analyzed for the time taken for skin closure, resultant scar, parental satisfaction, and complications, and the results were found to be statistically significant for the Amcrylate group. Amcrylate, when used as tissue glue for skin closure in cleft lip repair, definitely has an edge over conventional suturing techniques.

Dimensional changes in gypsum fragments bonded with cyanoacrylate

PURPOSE

Accidental fractures may occur during manipulation and transportation of plaster casts. In clinical practice, plaster fragments may be bonded without harming the accuracy of the final denture, provided that the bonding agent does not cause dimensional alterations. Cyanoacrylate could be a good material because of its ease of use, quick set, wide availability, and low cost. The aim of this study was to assess the dimensional alteration of Type IV plaster fragments bonded with a cyanoacrylate-based adhesive.

MATERIALS AND METHODS

Ten hexagonal regular prisms were made of Type IV plaster, with two reference marks on one of the faces. The distance between the marks was measured under a comparison microscope. After this, the prisms were fractured so that the fracture line would be between the two reference marks, bonded with a cyanoacrylate-based universal adhesive and measured again.

RESULTS

The mean difference between the measurements performed before and after fracture and bonding of the fragments was 0.0194 mm. At a level of significance of 0.05, there was no statistically significant difference between the measurements before and after fracture and bonding of the dies (p = 0.1582).

CONCLUSION

It may be concluded that bonding of Type IV plaster fragments with a cyanoacrylate-based adhesive did not cause significant dimensional alterations.

A comparative study: efficacy of tissue glue and sutures after impacted mandibular third molar removal

OBJECTIVE

To compare the efficacy of cyanoacrylate (tissue glue) placement after surgical removal of impacted mandibular third molars.

MATERIALS AND METHODS

Thirty patients with bilaterally impacted mandibular third molars were studied in this controlled clinical trial. One side closure after surgical removal of third molar was done with conventional sutures and other side with cyanoacrylate.

RESULTS

The data analysis showed that postoperative bleeding with cyanoacrylate method was less significant than with suturing on the first and second day after surgery. There was no significant difference in the severity of pain between the two methods.

CONCLUSION

This study suggested that the efficacy of both, cyanoacrylate and suturing in wound closure were similar in the severity of pain, but use of cyanoacrylate showed better hemostasis.

Upgraded nerve growth factor expression induced by low-intensity continuous-wave ultrasound accelerates regeneration of neurotometicly injured sciatic nerve in rats

Low-intensity ultrasound (LIU) can stimulate injured nerve regeneration but the mechanism is still unclear. We investigated the stimulating effect and its mechanism of continuous-wave LIU on neurotometic injury of sciatic nerve. The right sciatic nerves of 64 adult Wistar rats were first crushed and then exposed (32 rats) or sham-exposed (32 rats) to LIU at the crush site. The LIU had a spatial averaged and temporal averaged intensity of 0.25 W/cm(2) operated at 1.0 MHz for 1 min every other day. At various stages (the second, fourth, sixth and eighth weeks) after LIU exposure, the sciatic nerve function index (SFI), the sensory nerve conduction velocity (SNCV), the expression of nerve growth factor (NGF) and sample histology were studied. It was found that the density of nerve fibers with myelin sheath, SFI, SNCV and NGF expression of the treatment group were higher than that of control group (p < 0.05). It has been determined that LIU treatment can accelerate the regeneration and functional recovery of neurotometic injured sciatic nerve at earlier stages after injury, the upgraded expression of NGF induced by LIU may be the primary mechanism of the acceleration effects.

In vivo study of ethyl-2-cyanoacrylate applied in direct contact with nerves regenerating in a novel nerve-guide

Stitch suture is still the most recommended method to hold a nerve-guide in place but stitch suture is a well known cause of local inflammatory response. Glues of several kinds have been proposed as an alternative but they are not easy to apply in a real surgical setting. In 2006 authors developed a new concept of nerve-guide termed "NeuroBox" which is double-halved, not-degradable and rigid, and allows the use of cyanoacrylic glues. In this study, Authors analyzed histologically the nerve-glue interface. Wistar rats were used as animal model. In group 1, animals were implanted a NeuroBox to promote the regeneration of an experimentally produced 4 mm gap in the sciatic nerve. In group 2, the gap was left without repair ("sham-operated" group). Group 3 was assembled by harvesting 10 contralateral intact nerves to document the normal anatomy. Semi-thin sections for visible light microscopy and ultra-thin sections for Transmission Electron Microscopy were analyzed. Results showed that application of ethyl-2-cyanoacrylate directly to the epineurium produced no significative insult to the underlining nerve fibers nor impaired nerve regeneration. No regeneration occurred in the "sham-operated" group.

Ethyl-cyanoacrylate is acutely nontoxic and provides sufficient bond strength for anastomosis of peripheral nerves

Anastomosis is a common technique for the union of severed nerve trunks. This is commonly performed with sutures, a process that can be both time consuming and injurious to tissue. One promising alternative to suturing is the use of adhesives to join the severed segments. Cyanoacrylate-based glues have been used clinically as a surgical adhesive for soft tissues. However, the acute effects of these glues on nerve electrophysiology and the tensile strength of the rejoined tissues have not been evaluated. Using a guinea pig model, we analyzed the mechanical properties of transected sciatic nerves repaired with epineural application of ethyl-cyanoacrylate and the short term consequences of cyanoacrylate application on impulse conduction. Results showed that nerves coapted with ethyl-cyanoacrylate were capable of bearing in vivo forces. Additionally, no acute effects on conduction were observed in uninjured sciatic nerves exposed to ethyl-cyanoacrylate. In conjunction with long term in vivo reports from literature, the current results support the use of cyanoacrylates in nerve repair.

Platelet rich plasma may enhance peripheral nerve regeneration after cyanoacrylate reanastomosis: a controlled blind study on rats

The aim of this study was to explore the ability of platelet rich plasma (PRP) to promote peripheral nerve regeneration after cyanoacrylate reanastomosis in rats. A total of 18 rats were used in this study. Bilateral sciatic neurotomies were performed in 15 rats, and then immediately reanastomosed with cyanoacrylate glue. On one side (G1), the anastomosed nerves were treated with prepared autologous PRP gel; on the contralateral side (G2) the nerves received no additional treatment. Sham surgery was undertaken on the remaining 3 rats (6 cases) where bilateral sciatic nerves were surgically approached but not cut (passive control group, (G3). Biopsies were harvested 12 weeks postoperatively and examined under the light microscope using osmic acid stain. The number of nerve fibers in the distal and proximal nerve segments of G1 and G2 as well as in G3 were counted and the results analyzed and compared. Animals in G1 and G2 showed some weakness and ulceration in their right and left feet for a few weeks postoperatively, which gradually improved during the follow-up period. The histomorphometric assessment showed a higher axon count in the distal segment of G1 (291.7 axons) compared with that of G2 (280.5 axons) (P=0.001). Similar results were noticed when the proximal segments of both groups were compared (P=0.040). These results were reflected in the values of the neurotization indices of G1 (91.9%) and G2 (89.5%) (P=0.008). The number of nerve fibers in G1 and G2 remained lower than in G3 (P=0.0001). The authors conclude that PRP may enhance the number of regenerating nerve fibers after cyanoacrylate neruoanastomosis.