Comparison of a collagen membrane versus a fibrin sealant after a peroneal nerve section and repair: a functional and histological study

Fibrin gels and their clinical and bioengineering applications

Fibrin gels, prepared from fibrinogen and thrombin, the key proteins involved in blood clotting, were among the first biomaterials used to prevent bleeding and promote wound healing. The unique polymerization mechanism of fibrin, which allows control of gelation times and network architecture by variation in reaction conditions, allows formation of a wide array of soft substrates under physiological conditions. Fibrin gels have been extensively studied rheologically in part because their nonlinear elasticity, characterized by soft compliance at small strains and impressive stiffening to resist larger deformations, appears essential for their function as haemostatic plugs and as matrices for cell migration and wound healing. The filaments forming a fibrin network are among the softest in nature, allowing them to deform to large extents and stiffen but not break. The biochemical and mechanical properties of fibrin have recently been exploited in numerous studies that suggest its potential for applications in medicine and bioengineering.

Long-term results after operatively treated Achilles tendon rupture: fibrin glue versus suture

The use of fibrin glue for repairing Achilles tendon ruptures was introduced in the 1980s. Although fibrin glue has been in regular use since that time, suturing remains the standard for surgical repair. Studies have indicated that, in the short term, fibrin glue is as effective as suturing. To date, there have been no long-term studies comparing the outcomes of these 2 techniques. This study compares the long-term results of surgical repair of Achilles tendon rupture with sutures versus fibrin glue. Forty-two patients who had undergone Achilles tendon repair with either suture or fibrin glue took part in a follow-up examination after an average of 12.1 years. The fibrin group consisted of 31 patients and the suture group consisted of 11 patients. Patients treated with fibrin glue reached a higher modified Thermann score (adapted from Weber), achieved equal results in an isokinetic force measurement, and showed fewer complications. The authors concluded that the use of fibrin glue for the repair of ruptured Achilles tendon is a suitable alternative to traditional sutures.

LEVEL OF CLINICAL EVIDENCE

2.

Comparative analysis of biomechanical performance of available "nerve glues"

PURPOSE

To compare a variety of potentially useful artificial and biological sealants applied to sutured nerve repairs to decrease gapping at the repaired site.

METHODS

Fifty-seven fresh-frozen cadaveric nerve specimens were transected and repaired with two 8-0 nylon epineural sutures placed 180 degrees apart. The specimens were divided into 5 groups. Four groups received augmentation of the repair with application of either autologous fibrin glue, Tisseel fibrin glue, Evicel fibrin glue, or DuraSeal polyethylene glycol-based hydrogel sealant, and the fifth group had no glue. Each nerve construct was mounted in a servohydraulic materials testing machine and stretched at a constant 5 mm/min displacement rate until failure. A noncontact video analysis permitted normalization of stretch within the repair region. Statistical analysis was performed via analysis of variance followed by Tukey-Kramer post hoc pairwise comparison when indicated.

RESULTS

Resistance to gapping as measured through normalized stiffness (N/mm/mm) was greater for the Tisseel group, Evicel group, and DuraSeal group versus the no-glue group only. The stiffness of the autologous group approached significance versus the no-glue group. There were no significant differences in stiffness between any of the nerve glue groups. There was no statistical difference for the peak load at failure between any of the groups.

CONCLUSIONS

Avoidance of gapping at the nerve repair site is crucial in achieving successful nerve regeneration. Commercially available tissue sealants (Tisseel, Evicel, and DuraSeal), when used to augment 2-suture nerve repairs, as in our protocol, help prevent this initial gapping. None of the tissue sealants tested, however, increased the ultimate load to complete failure of the repair.

Maxillary sinus floor augmentation using autogenous bone grafts and platelet-enriched fibrin glue with simultaneous implant placement

OBJECTIVE

The aim of this study was to evaluate the use of autogenous bone in combination with platelet-enriched fibrin glue as a grafting material for maxillary sinus augmentation with simultaneous implant placement in dogs.

STUDY DESIGN

The mucous membranes of 12 sinuses in 6 dogs were elevated bilaterally. In the right sinus, autogenous bone mixed with platelet-enriched fibrin glue was grafted into the space between the membrane and the sinus wall. In the left sinus, autogenous bone alone was grafted as a control. At the same time, 2 dental implants were inserted into the grafting material through the maxillary sinus floor. The animals were killed 6 months after surgery.

RESULTS

The mean bone-implant contact was 40.5% on the fibrin glue side and 32.3% on the control side (P < .05). The mean height of newly formed bone in the augmented area was 12.2 mm on the fibrin glue side and 10.7 mm on the control side (P < .05).

CONCLUSION

The results indicate that the use of autogenous bone mixed with platelet-enriched fibrin glue can achieve results superior to those for grafts of autogenous bone alone. The specific improvements of this technique include enhanced osseointegration of dental implants and increased height of new bone.

Platelet Gel Sealant Use in Rhytidectomy

BACKGROUND

A prospective study was used to evaluate the efficacy of a commercially available platelet gel product as a sealant to decrease postsurgical drain fluid rates and volumes in patients who have undergone rhytidectomy procedures. Quantitative assessments of postoperative drain fluid outputs were compared in subjects who did and did not receive platelet gel treatment.

METHODS

Autologous platelet concentrate was prepared from each subject (n = 19), combined with bovine thrombin to form a platelet gel, and applied during the rhytidectomy procedure. Surgical drains were placed and effluent was collected postoperatively at 8-hour intervals for 24 hours and the volumes were recorded. A retrospective examination of surgical drain output over time in subjects (n = 14) who did not receive platelet gel treatment was performed; this group served as the control group.

RESULTS

Subjects who received the platelet gel sealant treatment had significantly decreased surgical drain fluid levels over 24 hours [109 +/- 8.5 ml (mean +/- SEM)] compared with subjects who did not receive the platelet gel sealant (78 +/- 7.5 ml) (p < 0.02). From 0 to 8 hours postoperatively, platelet gel-treated subjects had a mean 35 percent decrease in fluid levels compared with the controls (p < 0.03). No difference in surgical drain outputs was observed from 8 to 16 hours between the two experimental groups. From 16 to 24 hours, the control group had increased mean fluid levels (20 percent) and the platelet gel sealant group output levels decreased (50 percent).

CONCLUSIONS

Platelet gel sealant treatment was associated with decreased surgical fluid drain output in the first 24 hours postoperatively.

Effects of Tissucol and epsilon aminocaproic acid in the healing process following dental extraction in dehydrated rats

A histological study was conducted of the alveolar bone healing process following tooth extraction of dehydrated rats after the implantation of fibrin adhesive (TISSUCOL) associated to previous irrigation of the wound with a 5% epsilon aminocaproic acid solution (EACA). Seventy two rats were used, divided into three groups receiving different treatments after the surgical procedure. In group I, the gingival mucosa was sutured after extraction of the right upper incisor. In groups II and III, chronic dehydration was produced by water deprivation for 9 days (3 days in the preoperative period and 6 days in the postoperative period). In the animals of Group II, after tooth extraction, the gingival mucosa was sutured in the same way as performed in group I. In group III, after extraction, the dental socket was irrigated with 5% EACA, followed by implantation of the fibrin adhesive (TISSUCOL). The mucosa was sutured in the same way as performed in the other groups. At 3, 7, 15 and 21 postoperative days, the animals were sacrificed in number of 6 for each group. Specimens containing the dental socket were removed and fixed in 10% formalin and decalcified in an equal part formic acid and sodium citrate solution. After routine processing, the specimens were embedded in paraffin for microtomy. We obtained 6 microm semi-serial slices that were stained with hematoxylin and eosin for histological evaluation. The results showed that the water deprivation in the pre- and postoperative periods caused a delay in the alveolar bone healing process. The use of the fibrin adhesive (TISSUCOL) produced an improvement in the fibrinolytic picture caused by dehydration.

The effect of platelet-enriched fibrin glue on bone regeneration in autogenous bone grafts

OBJECTIVE

The aim of this study was to examine the ability of platelet-enriched fibrin glue to enhance bone formation in critically sized defects in the dog mandible.

STUDY DESIGN

Seven adult female mongrel dogs underwent continuity resections on both sides of the mandible; 1 defect was reconstructed with the original particulate bone mixed with platelet-enriched fibrin glue, and as a control the contralateral defect was reconstructed with the original particulate bone alone.

RESULTS

Biopsies after 6 weeks showed that the addition of platelet-enriched fibrin glue enhanced new bone formation in the autogenous bone grafts.

CONCLUSION

Our data suggest that fibrin nets formed by fibrinogen, in combination with growth factors present in platelet-enriched fibrin glue, might effectively promote bone healing at bone graft sites.

A comparative histologic analysis of tissue-engineered bone using platelet-rich plasma and platelet-enriched fibrin glue

OBJECTIVE

The aim of this study was to compare the effects of platelet-rich plasma (PRP) and platelet-enriched fibrin glue on bone formation in bone tissue engineering.

STUDY DESIGN

PRP was mixed with bone marrow mesenchymal stem cells and bone morphogenetic protein-2 (BMP-2), and the composites were injected into the subcutaneous space on the dorsum of nude mice. On the contralateral side of the dorsum, platelet-enriched fibrin glue/bone marrow mesenchymal stem cells/BMP-2 composites were injected. Bone formation was evaluated after 12 weeks.

RESULTS

The volumes of subcutaneous nodules formed in nude mice were 55 +/- 18 microL at the PRP/bone marrow mesenchymal stem cells/BMP-2 sites and 135 +/- 27 microL at the platelet-enriched fibrin glue/bone marrow mesenchymal stem cells/BMP-2 sites. Histomorphometric analysis demonstrated that the nodules contained 14.9 +/- 4.1% newly formed bone when using PRP and 19.8 +/- 3.6% newly formed bone when using platelet-enriched fibrin glue.

CONCLUSION

The results indicated that the osteogenic characteristics of platelet-enriched fibrin glue are superior to PRP in bone tissue engineering.

The use of autologous fibrin glue for closing sinus membrane perforations during sinus lifts

Sinus lift procedures depend greatly on fragile structures and anatomical variations. These procedures may cause sinus membrane perforations, which can lead to graft infection and early failure. The aim of this study was to assess the efficacy of autologous fibrin glue in the management of large perforations of the maxillary sinus membrane occurring during sinus lifts. After elevating the sinus membrane in the bilateral maxillary sinuses of 6 adult female mongrel dogs, a laceration (about 2.0 cm in length) was made in the membrane and either repaired with autologous fibrin glue or covered with a bioabsorbable collagen membrane as a control. Wounded areas were biopsied 2 weeks after the operation. Wounds repaired with autologous fibrin glue showed newly formed continuous epithelium across the previous perforation site. However, extensive fibrosis, inflammatory infiltration, and absent epithelium were observed in wounds treated with the collagen membrane control. Our results support the clinical use of autologous fibrin glue for repairing sinus membrane perforations.

Octyl 2-Cyanoacrylate for Repair of Peripheral Nerve

The repair of peripheral nerves with sutures is time consuming. The aim of this study was to evaluate the benefits and functional outcome of repairing nerves with octyl 2-cyanoacrylate adhesive. The right peroneal nerve of 64 male, Lewis rats was sectioned and repaired. The rats were randomized into 3 experimental groups: A (n = 27), using only octyl 2-cyanoacrylate; B (n = 27), using 4, 10-0 nylon sutures; and C (n = 10), a sham operation. The recovery of nerve function was quantified through walking-track analyses; group A showed faster return of nerve function than B, especially at 15 days (P < 0.017). Histologic analysis showed a greater axonal regeneration in group A versus group B and no indication of tissue toxicity in group A. No dehiscence occurred during the 6-month study. Use of adhesive shortened the anastomosis time from 12 minutes to 4 minutes. These results indicate that the use of octyl 2-cyanoacrylate adhesive for nerve anastomoses is safe and effective and may have benefits compared with the use of sutures.

Autologous fibrin glue in peripheral nerve regeneration in vivo

The activity of several growth factors on peripheral nerve regeneration is reported. Autologous fibrin glue contains a large number of platelets, which release significant quantities of growth factors. In order to understand the role of autologous fibrin glue in peripheral nerve regeneration, a 15-mm rabbit peroneal nerve defect was repaired using a vein graft filled with autologous fibrin glue. Axonal regeneration was examined using histological and electrophysiological methods. The extent of axonal regeneration was superior when treated with autologous fibrin glue. Our data suggest that fibrin nets formed by fibrinogen, in combination with growth factors present in autologous fibrin glue, might effectively promote peripheral nerve regeneration in nerve defects.

Reduction of Bone Resorption by the Application of Fibrin Glue in the Reconstruction of the Alveolar Cleft

A major complication in 30% to 75% of cases of surgical treatment of alveolar cleft is resorption of the bone graft. A treatment alternative is the application of fibrin glue, which has the capacity to favor the integration of the graft. The main objective of the study was to evaluate if the use of the fibrin glue reduces bone resorption when it is applied locally. The authors designed a randomized clinical trial. Patients were divided into two groups: group 1, fibrin glue; and group 2, control. Pre- and postoperative graft volume, bone density, bone quality (Lekholm and Zarb, and Norton and Gamble classifications), and postoperative complications were evaluated. The follow-up for all patients was 3 months after discharge. Twenty-seven patients were surgically treated, 13 in group 1 and 14 in group 2. Group 1 had increased graft volume compared with group 2 (64.32 cm v 21.70 cm; P < 0.0001). Bone density was higher in group 1 than in group 2 (396.57 v 245.68; P > 0.076). Bone quality was type 1, 2 and 3 and 4 in group 1. Resorption in group 2 was 62.26%; in group 1, it was 29.72% (P > 0.081). The observed complications were infection and dehiscence of sutures (P > 0.537). The authors conclude that the fibrin glue significantly diminishes bone resorption, allowing improved graft integration and quality.

Facial nerve repair with epineural suture and anastomosis using fibrin adhesive: An experimental study in the rabbit

PURPOSE

An experimental model in rabbits was used to compare epineural suturing and fibrin adhesive anastomosis for facial nerve repair.

MATERIALS AND METHODS

Thirty-four facial nerves from 17 rabbits were isolated, transected, and anastomosed, with an evaluation of their electrophysiologic and histologic parameters. The rabbits were divided into 2 groups of 5 and 12 animals, respectively: a 10-mm defect was made in the right facial nerve in the first group, with transection and epineural suturing of the left nerve, followed by death after 120 days. This was the control-versus-epineural suture group. In the second group, the right facial nerve was transected and subjected to epineural suturing, while the left nerve was transected and anastomosed using fibrin adhesive. The rabbits were killed 15, 30, 60, and 120 days after the microsurgical procedure. This was the epineural suture-versus-fibrin adhesive group.

RESULTS

From day 30, the number of regenerated axons increased with time in the epineural suture and fibrin adhesive anastomotic specimens. Epineural suture showed more regenerated axons and a faster linear rate of regeneration than anastomosis with fibrin adhesive. The reduction in conduction velocity decreased significantly with time with the same linear pattern for both suture techniques.

CONCLUSIONS

Epineural suturing offered superior performance versus anastomosis with fibrin adhesive in terms of axon count but not in decrease in conduction velocity.

An eclectic history of peripheral nerve surgery

It is hard to decide where history stops and contemporary development of peripheral nerve surgery begins. This article provides an eclectic view of the history of peripheral nerve surgery. In trying to keep the story moving, the publications of many authors have been omitted. For this, we are sorry. We have also stopped short of reporting the contemporary history of molecular biology as applied to peripheral nerve regeneration. The future of peripheral nerve repairs lies in our understanding of the molecular cascades that stimulate axon growth and guide the axon to its proper destination. We hope that this review shows the reader that researchers who got us where we are traveled a road filled with erroneous dogma, bad advice,and misleading data. We believe that the lessons learned from those who brought us back to the right path are applicable to many disciplines.

Sex-related differences in the regeneration of sensory axons and recovery of nociception after peripheral nerve crush in the rat

Sex-related differences regarding the regeneration of nociceptive axons and the recovery of nociception after sural nerve crush injury were examined in rats. The elongation rate of the fastest regenerating sensory axons in females started to increase after the first 6 days. This resulted in about 15% greater axon elongation distance at 8 days after crush in female than in male rats as determined by the nerve pinch test. The number of regenerating sensory axons in female and male rats, however, was not different. The recovery of nociception in the instep started earlier and was more extensive in females than in males during the entire 24-week recovery period, so that the pain sensitive area was finally about 20% larger in females than in males. Although ovariectomy significantly reduced plasma estradiol concentration in female rats, it did not change the elongation distance of regenerating nociceptive axons, which remained significantly greater than in male rats. Elimination of the cells in the distal nerve segment by freezing revealed that a more effective cell support in the distal nerve segment is probably responsible for faster regeneration of nociceptive axons in females than in males, rather than the circulating female sex hormones.

Estudo morfológico das entero-anastomoses com suturas em pontos separados complementados com adesivo sintético ou biológico em coelho

OBJETIVO: Verificar a eficácia dos adesivos de fibrina e cianoacrilato como coadjunvantes nas anastomoses de intestino delgado de coelhos. MÉTODOS: Oitenta coelhos, linhagem Nova Zelândia, machos, adultos, foram submetidos a enterectomia de 3cm e enterorrafia e distribuídos em quatro grupos: Grupo A (dois pontos eqüidistantes); Grupo B (quatro pontos eqüidistantes); Grupo C (seis pontos eqüidistantes); Grupo D (oito pontos eqüidistantes). No 14º dia de observação, os animais foram submetidos a uma laparotomia mediana para estudo macroscópico da cavidade abdominal para identificação e avaliação de aderências, deiscências e/ou fístulas. O segmento intestinal anastomosado foi retirado e feito um molde de alginato para posterior avaliação do índice de estenose. As peças retiradas foram processadas para estudo histológico e avaliação de fibras colágenas, macrófagos, neovascularização e granuloma tipo corpo estranho. RESULTADOS: Não houve diferença significante na avaliação de deiscência e fístulas com os dois adesivos entre os quatros sub-grupos. A aderência ocorreu em maior número nos sub-grupos do adesivo sintético. O índice de estenose foi maior nos animais do adesivo sintético somente nos sub-grupos com dois e oito pontos. A análise histológica mostrou que em todos os parâmetros avaliados (macrófago, neovascularização e granuloma) não houve diferença significante entre os dois tipos de adesivos. Em relação a porcentagem de colágeno verificou-se que houve diferença significante somente no grupo B em que o adesivo sintético foi menor que o biológico. CONCLUSÃO: O adesivo biológico de fibrina mostra mais eficácia que o adesivo sintético como complemento de suturas nas anastomoses intestinais.

Sex-related difference in collateral sprouting of nociceptive axons after peripheral nerve injury in the rat

Possible sex-related differences in the extent of collateral sprouting of noninjured nociceptive axons after peripheral nerve injury were examined. In the first experiment, peroneal, tibial, and saphenous nerves were transected and ligated in female and male rats. Eight weeks after nerve injury, skin pinch tests revealed that the nociceptive area of the noninjured sural nerve in the instep skin expanded faster in females; the final result was a 30% larger increase in females than in males. In the second experiment, the end-to-side nerve anastomosis was used as a model for axon sprouting. In addition to the previous procedure, the end of an excised peroneal nerve segment was sutured to the side of the intact sural nerve. Eight weeks later, collateral sprouting of nociceptive axons into the anastomosed peroneal nerve segment was assessed by the nerve pinch test and axon counting. There was no significant difference with respect to the percentages of male and female rats with a positive nerve pinch test. The number of myelinated axons in the anastomosed nerve segment was significantly larger in female (456 +/- 217) than in male (202 +/- 150) rats, but the numbers of unmyelinated axons were not significantly different. In normal sural nerves, the numbers of either all myelinated axons or thin myelinated axons did not significantly differ between the two sexes. Therefore, the more extensive collateral axon sprouting observed in female than in male rats is probably due to the higher sprouting capacity of thin myelinated sensory axons in females.

Reparação microcirúrgica de nervo periférico por meio de sutura, cola de fibrina ou bainha de BioFill® em ratos Wistar

Com o objetivo de comparar três técnicas de neuroanastomose, foram utilizados 54 ratos fêmeas, distribuídos em três grupos de 18 animais, cujos nervos ciáticos direitos foram transeccionados e, em seguida, tratados mediante o emprego das seguintes técnicas: três pontos de sutura epineural, um ponto de sutura epineural associado à bainha de BioFill® e um ponto de sutura epineural com cola de fibrina. A presença do material de sutura foi responsável pelo mau direcionamento das fibras nervosas e formação de neuroma na área da anastomose devido à colisão das fibras nervosas em regeneração com a reação granulomatosa ao fio de sutura. Alterações como degeneração Walleriana, formação de neuroma e proliferação de tecido fibroso foram observadas nos três tratamentos, sendo mais evidentes no grupo que recebeu três pontos de sutura epineural. Os resultados histológicos superiores obtidos com o emprego da bainha de BioFill® e da cola de fibrina comprovaram a eficiência dessas duas técnicas na reparação de nervos periféricos lesados. O uso da bainha de BioFill® oferece vantagens como disponibilidade, simplicidade técnica e baixo custo, tornando-a a melhor alternativa na reparação microcirúrgica do nervo periférico.

Fibrin sealants and platelet preparations in bone and periodontal healing

Fibrin sealants and platelet concentrates have been used alone or in association with bone substitutes to promote bone healing in orthopedic and oral surgery. Commercial fibrin sealants are homologous plasma-derived products that mimic the last step of a coagulation cascade, leading to a fibrin clot. They are used for topical hemostasis and tissue sealing and as melting agents for particulate bone substitutes. Infectious risk led to the development of autologous fibrin sealants from the patient's own plasma. However, their fabrication results in less reproducible or less satisfactory rheologic properties. The use of autologous products with high platelet concentrations, such as platelet-rich plasma, platelet concentrate, and platelet gels, has recently been suggested for combining the fibrin sealant properties with the growth factor effects of platelets. We describe the characteristics and limitations of fibrin sealants (commercial/autologous) and platelet preparations and review their effects on bone and periodontal healing as reported in experimental studies and clinical trials.

Bone regeneration following injection of mesenchymal stem cells and fibrin glue with a biodegradable scaffold

AIM

The purpose of this study was to determine whether a combination of fibrin glue, beta-tricalcium phosphate as a biodegradable (beta-TCP) and mesenchymal stem cells would provide three-dimensional templates for bone growth resulting in new bone formation at heterotopic sites in the rat with plasticity.

MATERIAL AND METHODS

Growing stem cells and developing matrices, explanted from the rat femur, were fragmented and mixed with fibrin glue in a syringe. The cells/beta-TCP fibrin glue admixtures were injected into the subcutaneous space on the dorsum of the rat.

RESULTS

Eight weeks after implantation, gross morphology revealed a pearly opalescence and firm consistency. Histological inspections showed newly formed bone structures in all admixtures, but none in the control groups when only fibrin glue and beta-TCP were injected. Osteopontin, a protein important in bone development, was identified by using antibodies in all cells/beta-TCP fibrin glue admixtures.

CONCLUSION

Mesenchymal stem cells/beta-TCP fibrin glue admixtures can result in successful bone formation. This technique holds the promise of a minimally invasive means of generating autogenous bone to correct or reconstruct bony defects.

The effect of hyperbaric oxygen treatment on early regeneration of sensory axons after nerve crush in the rat

Abstract The effect of hyperbaric oxygen treatment (HBO) on sensory axon regeneration was examined in the rat. The sciatic nerve was crushed in both legs. In addition, the distal stump of the sural nerve on one side was made acellular and its blood perfusion was compromised by freezing and thawing. Two experimental groups received hyperbaric exposures (2.5 ATA) to either compressed air (pO2 = 0.5 ATA) or 100% oxygen (pO2 = 2.5 ATA) 90 minutes per day for 6 days. Sensory axon regeneration in the sural nerve was thereafter assessed by the nerve pinch test and immunohistochemical reaction to neurofilament. HBO treatment increased the distances reached by the fastest regenerating sensory axons by about 15% in the distal nerve segments with preserved and with compromised blood perfusion. There was no significant difference between the rats treated with different oxygen tensions. The total number of regenerated axons in the distal sural nerve segments after a simple crush injury was not affected, whereas in the nerve segments with compromised blood perfusion treated by the higher pO2, the axon number was about 30% lower than that in the control group. It is concluded that the beneficial effect of HBO on sensory axon regeneration is not dose-dependent between 0.5 and 2.5 ATA pO2. Although the exposure to 2.5 ATA of pO2 moderately enhanced early regeneration of the fastest sensory axons, it decreased the number of regenerating axons in the injured nerves with compromised blood perfusion of the distal nerve stump.

Interneuronal signalling is involved in induction of collateral sprouting of nociceptive axons

Collateral sprouting of cutaneous nociceptive axons into the adjacent denervated skin critically depends on the nerve growth factor, presumably originating from the degenerated neural pathways and denervated skin. We hypothesised that the degenerated neural pathways are necessary, but not sufficient, to induce collateral sprouting of nociceptive axons, and, in addition, that the interaction between the injured and non-injured neurones within a dorsal root ganglion can trigger sprouting of nociceptive axons also in the absence of the denervated skin. End-to-side nerve anastomosis, made in female Wistar rats by suturing the end of an excised peroneal nerve segment to the side of the intact sural nerve, was used as a model for sprouting which allowed us to study the putative induction mechanisms separately. If the nerves adjacent to the sural nerve were transected concomitantly with the coaptation of the end-to-side anastomosis, robust nociceptive axon sprouting into the anastomosed nerve segment was observed by the nerve pinch test and counting of myelinated axons. Collateral sprouting did not occur, however, either if the cells in the anastomosed nerve segment were killed by freezing and thawing, or if the adjacent nerves had not been injured. However, if the ipsilateral dorsal cutaneous nerves, having their neurones in the same dorsal root ganglia as the sural nerve, were transected, but no other nerves were injured, then the sural nerve axons sprouted in abundance through the anastomosis even in the absence of denervated skin around the sural nerve terminals. From these results we suggest that cells (probably proliferating Schwann cells) in the degenerated neural pathways are necessary but not sufficient to induce collateral sprouting of nociceptive axons, and that interactions between the injured and non-injured neurones within the dorsal root ganglion (i.e. direct or indirect interneuronal signalling) are important in this regard.

Dural substitute for long-term imaging of cortical activity in behaving monkeys and its clinical implications

We present a transparent silicone dural substitute, which we have been using for the last 7 years for imaging cortical dynamics in awake behaving monkeys. This substitute enabled us to record optically for more than a year intrinsic or voltage sensitive dye signals. It is thin and elastic enough to allow microelectrode to pass through without any damage, using full visual control to target the electrode to the desirable recording site. This implant has proved crucial for maintaining the cortex in a good physiological condition and for preserving its optical characteristics that are necessary for optical imaging. We describe the details of the surgical implantation of the silicone dural substitute, the maintenance of the exposed cortex over long periods of time, the cortical reaction to this implant and its possible clinical implications in humans, and the rehabilitation procedure in monkeys.

The use of fibrin glue in skin grafts and tissue-engineered skin replacements: a review

Fibrin glue has been widely used as an adhesive in plastic and reconstructive surgery. This article reviews the advantages and disadvantages of its use with skin grafts and tissue-engineered skin substitutes. Fibrin glue has been shown to improve the percentage of skin graft take, especially when associated with difficult grafting sites or sites associated with unavoidable movement. Evidence also suggests improved hemostasis and a protective effect resulting in reduced bacterial infection. Fibrin, associated with fibronectin, has been shown to support keratinocyte and fibroblast growth both in vitro and in vivo, and may enhance cellular motility in the wound. When used as a delivery system for cultured keratinocytes and fibroblasts, fibrin glue may provide similar advantages to those proven with conventional skin grafts. Fibrin glue has also been shown to be a suitable delivery vehicle for exogenous growth factors that may in the future be used to accelerate wound healing.

Comparação entre cola biológica e sutura em cicatrização da pele

OBJETIVO: A utilização da cola biológica em diversos campos da cirurgia continua controversa, apesar do grande número de pesquisas. O objetivo do presente trabalho foi comparar a cicatrização da pele de ratos submetidos à sutura e à aplicação de cola biológica em distintos períodos pós-operatórios. MÉTODO: Em 10 ratos machos, foram confeccionados dois retalhos de pele em forma de "U" na região dorsal. Um dos retalhos foi suturado com fio de polipropileno 6-0, enquanto o outro foi fixado com cola biológica à base de gelatina-resorcinol formaldeído (GRF). Metade dos animais (n=5) foi acompanhada por um período de oito dias, enquanto os outros cinco foram estudados durante 21 dias. Avaliaram-se os aspectos macro e microscópio das cicatrizes. RESULTADOS: Após oito dias, a ferida em presença da cola biológica mostrou maior inflamação e reação cicatricial mais exuberante. Contudo, decorridos 21 dias, não houve diferença entre a cicatrização dos retalhos cutâneos em presença de fio de polipropileno ou cola biológica. CONCLUSÃO: Os resultados indicam que a cola biológica parece ser uma boa alternativa para a síntese de pele em rato.

Reconstruction of rat peripheral nerve gap without sutures using freeze-dried alginate gel

Many materials have been used for artificial tubular prostheses to assist peripheral nerve gap reconstruction. However, the clinical use of these devices has been restricted because a microsurgical procedure requires specialized techniques and expensive equipment, such as operating microscope systems. Therefore the authors developed a new gluing method, without sutures, that uses freeze-dried alginate gel. A 7-mm gap in the sciatic nerve of rats was bridged with freeze-dried alginate gel. Regeneration was evaluated by electrophysiologic testing and histologic study. Eighteen weeks after surgery, functional reinnervation of motor and sensory nerves had occurred, as demonstrated by recovery of compound muscle action potentials (CMAP), compound nerve action potentials (CNAP), and somatosensory-evoked potentials (SEP). Histologically, many regenerated nerve fasciculi, including myelinated and unmyelinated fibers, were observed and the implanted alginate gel had disappeared. In conclusion, a gluing technique using alginate gel is a potential alternative to the conventional nerve autograft technique. Advantages include simple application and rapid repair. Freeze-dried alginate gel is a promising material for artificial nerve guides for peripheral nerves and also could be used for repair of disrupted pathways in central nervous tissue that is amorphous and cannot be sutured.

Experimental use of fibrin glue to induce site-directed osteogenesis from cultured periosteal cells

The purpose of this study was to determine whether a combination of fibrin glue and cultured periosteal cells will result in new bone formation at heterotopic sites in nude mice. Growing cells and developing matrices surrounding periosteal explants from the diaphyses of radii of newborn calves were minced and mixed with fibrin glue in a syringe. The cell/matrix-fibrin glue admixture was then injected into the subcutaneous space on the dorsum of athymic nude mice. After 12 weeks of implantation, gross morphology and histologic investigations showed newly formed bone structures in all cell/matrix-fibrin glue admixtures, but none in fibrin glue injected alone and used as control samples. Osteopontin, a protein important in bone development, was identified by a Western blot assay of the cell/matrix-fibrin glue composite. This study supports the feasibility of initiating site-directed formation of bone structures at heterotopic tissue sites by means of injection of cultured periosteal cells and matrix in a fibrin glue carrier.

A conditioning lesion promotes in vivo nerve regeneration in the contralateral sciatic nerve of rats

A conditioning lesion in the sciatic nerve increases in vivo axonal regeneration in the nerve after a second transection. We studied whether this increased regeneration also occurs in the contralateral nerve. The left sciatic nerve was transected and sutured in Wistar rats; the nerve was exposed but not transected in controls. After 5 days, the right sciatic nerves of all rats were transected and sutured. Neuronal regeneration was measured at 0, 1, 3, 5, and 7 days with the pinch test and histological staining. IL-1beta and TGF-beta1 expression was also measured. The initial delay in the experimental group was significantly shorter, but the regeneration rates were the same. The expression of IL-1beta and TGF-beta1 in the right dorsal root ganglia was significantly higher in the experimental group. Nerve injury enhances cytokine expression in the contralateral dorsal root ganglion and promotes contralateral nerve regeneration in vivo by shortening the initial delay.

The influence of delay and the effect of fibrin sealant on the cut surface of the peripheral nerve. An experimental study in the rat

Thirty-two sciatic nerves in 16 rats were divided to investigate the effect of delay in fixation and the use of fibrin sealant at the site of the division on the nerve end. Specimens were assessed by morphological and morphometric criteria using scanning electron microscopy and longitudinal sections. All specimens showed a protruded nerve end. Wrapping the nerve with fibrin sealant before division and immediate fixation of the specimen resulted in less protrusion.

Recovery of cutaneous pain sensitivity after end-to-side nerve repair in the rat

OBJECT

The hypothesis that collaterally sprouting axons from an uninjured donor nerve may provide recovery of pain sensitivity in the skin after end-to-side nerve repair was investigated in rats. In addition, the effect of this technique on the donor nerve was examined.

METHODS

The distal stump of the transected peroneal nerve was sutured end to side to the intact sural nerve. No epineurial window or perineurial slit was made in the sural nerve at the site of coaptation. Other nerves in the leg were transected and ligated. Eighteen weeks later, the sural nerve was transected at a site distal from the coaptation site. The residual pain sensitivity in the peroneal innervation field in the instep was documented using the skin pinch test in three of 11 animals. The area of sensitivity encompassed 19 to 40% of the maximum nociceptive innervation area of the normal peroneal nerve. The nerve pinch test revealed functional sensory axons in all communicating peroneal nerves, in which 277+/-119 myelinated axons (mean +/- standard deviation) were found by histological investigation.

CONCLUSIONS

The authors conclude that at least partial recovery of sensory function due to collateral sprouting of axons after end-to-side nerve repair is possible in principle. However, the presence of functional sensory axons in the peroneal nerve stumps did not guarantee the recovery of skin sensitivity to pain in all animals. No functional or morphological evidence of an untoward effect of collateral sprouting into the end-to-side communicating nerve was detected in the axons of the donor nerve itself.

Sutureless and reduced suture anastomosis of hollow vessels with fibrin glue: a review

Research in reduced suture fibrin glue (FG) and sutureless FG anastomosis has been lagging behind FG utilization in other surgical fields. A review of the literature for vascular, esophageal, tracheal, gastrointestinal, common bile duct, ureteral, vas deferens, and Fallopian tube FG anastomosis indicates that reduced suture FG and sutureless FG procedures may be performed with less training, reduced operating time, leakage, ischemia, inflammation, and necrosis compared to sutured techniques. Reduced suture FG vascular anastomosis augments early anastomotic strength. Suture number for esophageal, tracheal, and tracheobronchial anastomoses can be reduced with FG. Bursting strength in pig small intestine and rat colon was lower at 4 days postoperatively, but returned to sutured strength at 7 days. Mortality was unaffected, and 18-month follow-up in sutureless FG intestinal anastomosis in pigs showed no stenosis. Preliminary ureteral studies have demonstrated successful sutureless FG and reduced suture FG laparoscopic techniques in pigs. Reduced suture FG and sutureless FG vas deferens anastomosis may reduce sperm granuloma rates, with increased patency and pregnancy rates. Patency and pregnancy rates have been similar for tubal FG, reduced suture FG, autologous fibrin glue (AFG), and sutured anastomosis. Any risk of viral transmission or immune response is eliminated by AFG. While there are few studies in many areas of FG hollow vessel anastomosis, the current literature illustrates many of the advantages of FG over other anastomotic techniques and should provide impetus for continued research in this promising field of surgery.

Long-term evaluation of functional nerve recovery after reconstruction with a thin-walled biodegradable poly (DL-lactide-epsilon-caprolactone) nerve guide, using walking track analysis and electrostimulation tests

This study was performed to evaluate the long-term functional nerve recovery after reconstruction of a 10-mm gap in the sciatic nerve of the rat, with a thin-walled nerve guide, composed of a biodegradable copolymer of DL-lactide and epsilon-caprolactone [p(DLLA-epsilon-CL)]. To evaluate both motor and sensory nerve recovery, walking track analysis and electrostimulation tests were carried out after implantation periods ranging from 3 to 52 weeks postoperatively. The first signs of both motor and sensory nerve recovery could be observed after 5 weeks. After 15 weeks, 70% of the sciatic function and 90% of the sensory nerve function had been recovered. After this period, the sciatic function index (SFI) did not improve further, whereas the sensory nerve function appeared to return to normal. When the results of the SFI measurements, minus those obtained from rats with severe automutilation, are extrapolated, further improvement of the SFI might be expected after 52 weeks. The fact that 100% sensory nerve recovery was obtained, as measured by the electrostimulation test, could be explained by sensory reinnervation from surrounding areas. The SFI was not fully reestablished because automutilation had a great impact on the use of walking track assessment.

Closure of mucosal defects over exposed mandibular plates using fibrin glue

BACKGROUND

Mandibular plates may become exposed following radiation therapy, infection, and mucosal necrosis. This may lead to early removal of the mandibular plates with subsequent instability of bone fragments.

OBJECTIVE

To compare fibrin glue, a bioadhesive, with traditional sutures in closing mucosa over exposed mandibular plates in a cat.

DESIGN

Prospective matched-pairs analysis.

SUBJECTS

Nine cats were used, and each cat served as its own control.

INTERVENTION

Bilateral mandibular plates were fixed on the buccal side of the mandible of 9 cats. The surgical defects over the plates were left uncovered. After 4 days, the plates on the right side were covered with a mucosal graft fastened with fibrin glue, and on the left side the grafts were secured with sutures. After 10 days, the grafts were excised and a histological examination was performed.

RESULTS

The mean operative time for coverage was 2 minutes 11 seconds for the fibrin glue and 12 minutes 48 seconds for the sutures (P < .001). Gross examination revealed granulation or ulceration in 3 of the fibrin and 9 of the suture specimens (P < .005). All specimens displayed mild-to-moderate acute and chronic inflammation. All sutured specimens showed focal foreign body-type giant cells surrounding fragments of bone and suture. Two mandibular plates were partially exposed on the fibrin glue side.

CONCLUSIONS

The use of fibrin glue to cover exposed mandibular plates is safe and well tolerated in cats. Glue application requires a shorter operative time and is associated with fewer occurrences of granulation and ulceration when compared with suture fixation. Further studies are indicated to titrate the concentration of fibrin glue and to prevent plate exposure.

Evaluation of application techniques of fibrin sealant to prevent cerebrospinal fluid leakage: a new device for the application of aerosolized fibrin glue

OBJECTIVE

This report evaluates the sealing effects of fibrin sealant applied on the dura mater using different techniques.

METHODS

Three application methods were studied: a sequential layer method, a simultaneous method using a cannula, and a spray method using a newly developed spray device. The sealing effects of these methods were compared using in vitro histological analysis and a pressure resistance test. The clinical efficacy of the fibrin sealant to prevent water leakage through the dura mater was retrospectively analyzed in a total of 509 patients. The process of absorption of a clinically applied fibrin clot in vivo was examined using surgical specimens.

RESULTS

The fibrin plate made using the spray method withstood a hydrostatic pressure greater than 200 cm H2O. A scanning electron microscopic study of the fibrin clots showed that the sequential and simultaneous methods produced a fibrin fiber network; in contrast, our spray method formed a dense fibrin tissue in which the fibrin molecules fused together forming stratified laminae. Of the 295 supratentorial craniotomies during which spraying was used, postsurgical cerebrospinal fluid leakage occurred in 9 cases (3.1%), whereas of the 214 craniotomies during which spraying was not used, cerebrospinal fluid leakage occurred in 19 cases (8.9%). Histological examinations of 10 surgical specimens obtained during second craniotomies revealed that the spray-made fibrin clots had been gradually replaced by mature granulation composed of collagenous connective tissue.

CONCLUSION

The optimal technique for applying fibrin sealant is the spray method that aerosolizes fibrin glue and produces a tough fibrin plate.

The management of peripheral arterial aneurysms using percutaneous injection of fibrin adhesive

Most peripheral arterial aneurysms are pseudoaneurysms and are iatrogenic or related to trauma. They can be treated by several techniques that can be performed by the radiologist, negating the need for surgery. Ultrasound guided compression repair is usually the treatment of choice, but is not always successful. The number of available treatment options reflects the varying site and nature of pseudoaneurysms and perhaps the lack of a consistently reliable method. We have successfully treated 13 patients with peripheral aneurysms (11 femoral, 1 popliteal and 1 posterior tibial aneurysm) using a commercial fibrin tissue adhesive. The method involves percutaneous injection of the adhesive components using ultrasound and screening control, following successful occlusion of the aneurysm neck by angioplasty balloon.

Fibrin glue terminates massive bleeding after complex hepatic injury

OBJECTIVE

We determined the ability of a packaged fibrin glue (FG) product to terminate severe bleeding in a new porcine model of complex hepatic injury.

METHODS

Femoral arterial and venous catheters were placed in pentobarbital-anesthetized swine (n=7 per group, 16-18 kg). Pigs received an external blast to the right upper abdomen at 0 minutes, followed by uncontrolled hemorrhage at 0 to 30 minutes, with anticoagulation (heparin, 200 U/kg) at 10 minutes. Pigs were resuscitated with lactated Ringer's solution (20 mL/kg) beginning at 15 minutes and then underwent laparotomy to control bleeding at 30 minutes. Lactated Ringer's solution was infused to keep mean arterial pressure greater than 70 mm Hg until 120 minutes, when repeat laparotomy was performed. Control animals (group 1) underwent routine surgical procedures to terminate bleeding followed by packing if hepatic bleeding continued. The FG animals (group II) underwent routine surgical procedures plus application of FG. Avoidance of packing, estimated blood loss (EBL) during and after laparotomy, and fluid resuscitation volume were the primary end points studied.

RESULTS

In both groups, mean arterial pressure varied significantly from baseline to 120 minutes (group I: 100+/-3 to 52+/-11 mm Hg; group II: 99+/-4 to 66+/-3 mm Hg). Temperature decreased at the end of each experiment (group I: 37+/-1 to 33+/-1 degrees C; group II: 37+/-1 to 34+/-1 degrees C). There were no group differences in EBL before laparotomy (0-30 minutes), but from initial laparotomy to repeat laparotomy (30-120 min), EBL (group I: 875+/-265 mL; group II: 300+/-59 mL) and total fluid resuscitation (group I: 2.9+/-0.4 L; group II: 1.9+/-0.3 L) were statistically significantly less in FG pigs. Of greatest importance, six of seven control pigs required packing, but none of the FG animals were packed and none bled at repeat laparotomy.

CONCLUSION

FG stopped bleeding and eliminated the need for packing in a model of severe liver injury. Further work in the clinical arena is warranted to determine the potential benefits of FG in arresting hemorrhage in hypotensive, hypothermic, coagulopathic trauma patients with complex visceral injuries.

The use of fibrin adhesive in sinus lift procedures

Sinus lift bone grafting has expanded the use of dental implants in reconstructions of the atrophic maxilla. Potential problems include sinus membrane tear, which can lead to graft infection and early failure. Attempts at managing sinus membrane perforations are often limited by difficulty of access, as well as by the friability of the soft tissue lining the sinus. Various techniques have been proposed for managing such membrane tears. The use of fibrin adhesive, however, may present a potential solution in such situations. This article reports our experience with the use of fibrin adhesive in sinus lift procedures, as well as on its autologous preparation.

Nerve anastomoses with human fibrin. Preliminary clinical report (56 cases)

Since 1980, 56 peripheral nerve repairs have been done with fibrin. For technical reasons, combined anastomoses have been chosen in brachial plexus repairs (23 cases), fibrin alone being used in most other cases (8 free flaps, 17 main trunks, 8 digital nerves). As a whole, results compare evenly with the so-called classical repair methods using stitches. The adhesive method's main advantage is the gain in operative time, without impairing precision. Secondary benefits, such as hemostasis and easier stabilization of small grafts, can be achieved. One question remains: what becomes of fibrin? The survey of present cases would tend to prove that axonal growth through the second anastomosis is impeded proportionally to the length of the graft. The possible action of fibrin in the alteration process leading to a sclerotic diaphragm is not elucidated to this day. Experimental as well as clinical research must be carried on, in order to improve this new way of repairing nerves.

S-100beta stimulates neurite outgrowth in the rat sciatic nerve grafted with acellular muscle transplants

S-100beta promotes neurite extension in vitro and motoneuron survival in the chicken embryo. We demonstrate here that local administration of S-100beta stimulates the sciatic nerve regeneration into acellular muscle grafts. Normally there is a 8-10 day delay in the regeneration of axons into such grafts. Local administration of S-100beta (0.5-1.0 microg/h) significantly stimulated regeneration into the grafts. In S-100beta treated grafts, the regeneration distance was increased with a factor of about 2.3 times as compared to vehicle treated grafts. The distance of regeneration was monitored with pinch test which detects sensory axons. Regenerating axons were growing outside the necrotic muscle cells as revealed with immunohistochemistry for the neurofilament light weight polypeptide. S-100beta was demonstrated immunocytochemically in motor neurons of the rat lumbar spinal cord and in large and medium sized neurons of the dorsal root ganglia. The results suggest that S-100beta is a physiological growth factor for peripheral nerve axons.

Fibrin sealant: scientific rationale, production methods, properties, and current clinical use

Fibrin sealant is a complex plasma-derived product which is increasingly used as a biodegradable tissue adhesive or sealant to stop or control bleeding or provide air and fluid tightness in many surgical situations. This review describes the historical development of current fibrin sealant preparations and the scientific rationale behind the alleged physiological benefits of its major plasma-derived components. A comparison in the extraction methods and viral reduction treatments applied to current commercial products and autologous preparations, and their respective advantages and limits, are discussed. Application devices used for surgical applications are described. A survey of the major clinical applications in various surgical areas is presented. Current issues in terms of viral safety, definition of optimal fibrin sealant composition, and regulatory concerns, especially to demonstrate clinical efficacy, are also included.