Antifibrinolytic additives to fibrin glue for laparoscopic wound closure in urinary tract

Fibrin matrices: The versatile therapeutic delivery systems

Fibrin sealants, that have been employed for over a century by surgeons to stop post surgery bleeding, are finding novel applications in the controlled delivery of antibiotics and several other therapeutics. Fibrinogen can be easily purified from blood plasma and converted by thrombolysis to fibrin that undergoes spontaneous aggregation to form insoluble clot. During the gelling, fibrin can be formulated into films, clots, threads, microbeads, nanoconstructs and nanoparticles. Whole plasma clots in the form of beads and microparticles can also be prepared by activating endogenous thrombin, for possible drug delivery. Fibrin formulations offer remarkable scope for controlling the porosity as well as in vivo degradability and hence the release of the associated therapeutics. Binding/covalent-linking of therapeutics to the fibrin matrix, crosslinking of the matrix with bifunctional reagents and coentrapment of protease inhibitors have been successful in regulating both in vitro and in vivo release of the therapeutics. The release rates can also be remarkably lowered by preentrapment of therapeutics in insoluble particles like liposomes or by anchoring them to the matrix via molecules that bind them as well as fibrin.

Fibrin glue as a drug delivery system

Fibrin glue has been used surgically for decades for hemostasis as well as a sealant. It has also been researched as both a gel for cell delivery and a vehicle for drug delivery. The drug delivery applications for fibrin glue span tissue engineering to chemotherapy and involve several mechanisms for drug matrix interactions and control of release kinetics. Additionally, drugs or factors can be loaded in the gel via impregnation and tethering to the gel through covalent linkages or affinity-based systems. This review highlights recent research of fibrin glue as a drug delivery vehicle.

Natura abhorret a vacuo--use of fibrin glue as a filler and sealant in neurosurgical "dead spaces". Technical note

OBJECTIVE

The objective of this study is to report our experience and illustrate our technique in the use of fibrin glue in the treatment of post-operatory cerebrospinal fluid (CSF) leaks and collections following different neurosurgical procedures.

METHODS

In a 3-year period, 40 subjects underwent endoscopic endonasal approach for different sellar and skull base lesions (three tuberculum sellae meningiomas, six craniopharyngiomas, three Rathke's cleft cysts and 28 pituitary macroadenomas), in which an intraoperative CSF leakage was evident. In such subjects, the fibrin glue was used as a first step of the final phase of the procedure-i.e. the reconstruction of the skull base defect-followed by the other materials employed. Furthermore, ten other patients, who had undergone transsphenoidal (four cases), spinal (two cases), posterior fossa (three cases) and transcortical intraventricular tumour removal (one case) neurosurgical procedures and developed CSF leaks or collections, were conservatively treated by single or repeated in situ injections of "modified" fibrin glue under local anaesthesia according to different described techniques. In total, 50 patients constitute the clinical material of the present study.

TECHNIQUE

In the cases where the fibrin glue was used during the reconstruction phase of the procedure (40 cases), the glue was injected inside the tumour cavity to fill the dead space left by the removal of the lesion. In case of post-operative CSF leak or CSF fluid collection (ten cases), after discarding 50-80% of the thrombin solution to obtain prevalence of the product's adhesive properties, fibrin glue was injected directly in the path of the CSF leak or into the collection cavity after aspiration of the collection's content. This was performed with the provided application system or through lumbar or Tuohy needles. Applications were repeated every 48 h until the disappearance of the leak. In all the treated cases, the disappearance of CSF leaks or collections was obtained with a number of applications ranging from one to five. Successful results are stable with a follow-up ranging from 6 months to 3 years.

CONCLUSIONS

In our experience, the injection of fibrin glue has proved to be effective in filling or sealing post-operative "dead spaces" and treating minor or initial CSF leaks resulting from procedures of transsphenoidal, cranial and spinal surgery, adding another possibility in the management of many of these dreadful complications.

Comparison of healing after cystotomy and repair with fibrin glue and sutured closure in the porcine model

PURPOSE

We compared healing after laparoscopic cystotomy using fibrin glue, sutures, or a combination to determine whether fibrin glue can obviate the need for sutures and whether there is any detriment when glue is used in the presence of sutures.

MATERIALS AND METHODS

In 24 Yorkshire pigs, a 3.5 cm vertical cystotomy was created laparoscopically and repaired as follows: Group 1--no closure; group 2--fibrin glue closure; group 3--suture repair; group 4--combined fibrin glue and suture repair. All animals had a Foley catheter for 1 week. In each group, three animals were harvested at 1 week (acute) and three animals were harvested at 6 weeks (chronic).

RESULTS

Acute: Group 1--all pigs had an unhealed defect that leaked when evaluated by cystography. Groups 2, 3, 4--mean leak pressures were 80, 97, and 60 cm H(2)O (P = 0.36), respectively. Mean bladder capacity was not significantly different between groups. Chronic: No leakage seen on a cystogram at 1 week; at 6 weeks, bladders were filled at > or =95 to 100 cm H(2)O without leakage. Histologically, there was more inflammation in the acute group v chronic group pigs. In the acute group pigs repaired with glue or suture + glue, there was more inflammation and less epithelial continuity than in the suture alone group. At 6 weeks, there was no difference between groups.

CONCLUSION

Fibrin glue provoked an intense inflammatory response that might have delayed healing acutely, resulting in a lower burst pressure in both scenarios in which it was used (i.e., alone or in combination with sutures). However, by 6 weeks, there did not seem to be any difference between groups either clinically or histopathologically.

The use of fibrin glue to stop venous bleeding in the epidural space, vertebral venous plexus, and anterior cavernous sinus: technical note

OBJECTIVE

Various techniques have been used to stop venous bleeding from the epidural space, vertebral venous plexus, and cavernous sinus. Here, we describe our experience with the use of fibrin glue to stop venous bleeding in these areas.

METHODS

During the last 8 years, the senior author (LNS) has used injection of Tisseel fibrin glue (Baxter Healthcare Corp., Deerfield, IL) into the epidural space (n = 200 patients), anterior cavernous sinus (n = 46 patients), vertebral venous plexus (n = 20 patients), and superior petrosal sinus (n = 20 patients) to assist in hemostasis. The technical nuances are illustrated in three videos.

RESULTS

Injection of fibrin glue in the epidural space, anterior cavernous sinus, and vertebral venous plexus yielded good results in assisting with hemostasis. Two patients experienced complications caused by occlusion of veins draining the brainstem after fibrin glue was injected into the superior petrosal sinus.

CONCLUSION

Fibrin glue injection is an excellent option for hemostasis in the epidural space, anterior cavernous sinus, and vertebral venous plexus. However, based on our experience, fibrin glue injection into the superior petrosal sinus is not recommended.

In vivo biological performance of composites combining micro-macroporous biphasic calcium phosphate granules and fibrin sealant

INTRODUCTION

Fibrin glues are currently used by surgeons and can facilitate the handling of biomaterials. Combining fibrin glue with calcium phosphate bioceramics gives a mouldable composite that cements the granules into the implantation site. In addition to the mechanical aspect of the composite, it has been suggested that the mixture also promotes wound healing. These human blood derivatives contain natural (aprotinin) or synthetic (tranexamic acid) antifibrinolytic substances. We compared the bioactivity of two composites combining calcium phosphate granules with two different types of fibrin glue, one with aprotinin and the other with tranexamic acid.

MATERIALS AND METHODS

The composite was composed of fibrin glue (Tissucol) and 1 to 2 mm granules of biphasic calcium phosphate granules (MBCP) with a volume ratio of 1 for 2. Bone cavities were drilled in 12 New Zealand rabbits and filled with a composite with aprotinin-fibrin glue on the right condyle and one with tranexamic acid-fibrin glue on the left condyle. The rabbits were randomized into two groups: 3 and 6 weeks of delay. Light microscopy, scanning electron microscopy and image analysis were performed.

RESULTS

No adverse reactions were observed in either sample. Bony ingrowth associated with bioceramic resorption by osteoclastic TRAP-positive cells was noted. No significant difference was observed between the two composites. The bony ingrowth and ceramic resorption were qualitatively and quantitatively similar with both composites.

CONCLUSION

This study demonstrated that the choice of a natural (aprotinin) or synthetic (tranexamic acid) antifibrinolytic agent in the fibrin sealant associated with calcium phosphate granules and used as a bone substitute had no effect on the bioactivity of the composite. It remained efficient in bone reconstruction, no adverse effects were observed, and the bony ingrowth was qualitatively and quantitatively equivalent with the two types of fibrin sealant.

Comparative study of the hemostatic efficacy of a new human fibrin sealant: is an antifibrinolytic agent necessary?

BACKGROUND

Sustained hemostasis by fibrin sealant (FS) is critically important when it is used in trauma surgery. To purportedly delay fibrin degradation and prevent premature hemostatic failure, some FS products added an antifibrinolytic agent (e.g., bovine aprotinin). The purpose of this study was to compare the overall hemostatic efficacy of a new inhibitor-free FS obtained from the American Red Cross (ARC-FS) to a clinically available aprotinin-containing FS preparation (Tisseel). The need for addition of an antifibrinolytic agent was assessed under normal and high-fibrinolytic conditions.

METHODS

The abdominal aortas of anesthetized rabbits were transected and anastomosed, end-to end, using only four interrupted sutures. The suture line was covered with approximately 2 mL of either type of FS and blood flow was restored. Blood loss was absorbed by gauze and measured. All rabbits were recovered and underwent histologic examination 4 weeks after operation. The efficacy of FS was also tested under a high-fibrinolytic state by treating the rabbits with human recombinant tissue plasminogen activator (0.15 mg/kg, 3-hour infusion). The investigators were blinded to the treatment groups.

RESULTS

The majority (11 of 12) of deaths occurred because of bleeding at the suture line within 7 days of surgery. Sustained hemostasis by FS (>1 week) was required for normal tissue healing and long-term survival of animals. Application of ARC-FS to the suture line produced immediate hemostasis in 43% of animals (three of seven), with mean blood loss of 4.8 +/- 1.8 mL, and 86% long-term survival. Tisseel application produced immediate hemostasis in 13% of animals (one of eight), with mean blood loss of 26.9 +/- 7.0 mL (p < 0.05 vs. ARC-FS) and survival rate of 37% (three of eight). Under high-fibrinolytic conditions, ARC-FS produced immediate and complete hemostasis in seven of eight animals (88%), whereas the Tisseel demonstrated complete hemostasis in one of seven (p < 0.01). The ARC-FS rabbits had a blood loss of 1.9 +/- 1.9 mL and survival rate of 75% (six of eight), whereas the Tisseel animals had a mean blood loss of 30 +/- 6.0 mL and survival rate of 43% (three of seven) (p < 0.01). No detrimental effect on healing was noted with either product.

CONCLUSION

ARC-FS provides effective and secure hemostasis against high-pressure arterial bleeding under both normal and high-fibrinolytic conditions. Addition of an antifibrinolytic agent such as aprotinin is not required to sustain the hemostatic function of this fibrin sealant.

Comparison of 2-octyl cyanoacrylate adhesive, fibrin glue, and suturing for wound closure in the porcine urinary tract

OBJECTIVES

To evaluate 2-octyl cyanoacrylate glue (OCG) for wound closure in the urinary tract and compare the ability of OCG, fibrin glue (FG), and suture to withstand physiologic and supraphysiologic stress, because the use of tissue adhesives such as OCG or FG might simplify laparoscopic surgery.

METHODS

Female domestic pigs (n = 22) underwent a 7.5-cm cystotomy. Of these, 8 had closure with OCG and 8 with FG (6 open and 2 laparoscopic in each group). The controls were closed with suture (n = 4) or not at all (n = 2). Postoperative catheter drainage was not used. At 2 days or 4 weeks postoperatively, the bladders were filled with saline to 200 mm Hg pressure and the cystotomy scars inspected for leakage. The excised scars were also examined histologically.

RESULTS

The 2 OCG and 2 FG pigs tested on postoperative day 2 leaked at less than 200 mm Hg. None of the 6 OCG pigs tested at 4 weeks leaked at less than 200 mm Hg, including the 2 closed laparoscopically. Of the 6 FG pigs intended for study at 4 weeks, 3 (including the 2 closed laparoscopically) died from a massive urine leak, 1 tested at 4 weeks leaked, and 2 did not leak. Thus, 4 of 6 FG pigs leaked by 4 weeks compared with none in the OCG group (P = 0.06). The histologic examination was similar in the two groups.

CONCLUSIONS

Preliminary results suggest that OCG provides enough strength to hold together a large bladder wound. In the same model, FG did not consistently provide adequate closure.

Newer techniques in intracorporeal tissue approximation: suturing, tissue adhesives, and microclips

Great strides have been made in the discovery of alternative tissue approximation techniques for use in laparoscopy. Although none of the techniques have eliminated the need for suturing laparoscopically, their potential in achieving this end is promising. When an ideal approximation technique is discovered that is easy to use, safe, and reliably able to hold tissue together laparoscopically, laparoscopic reconstructive surgery should become less formidable and more appealing to urologists.

Fibrin glue applications in urology

Fibrin glue is used as a hemostatic and adhesive agent. Until recently, safety issues had delayed approval of the commercial preparation in the United States. Fibrin glue has found several urologic applications, especially as an adhesive agent. It has excellent potential in laparoscopic surgery, where conventional tissue approximation techniques are cumbersome and time-consuming. Fibrin glue has also been used as a delivery vehicle for autologous cell transplantation and may play a major role in tissue engineering techniques in the future.