Covidien gained FDA approval this week for its DuraSeal for the sealing of sutured dural tears, which occur in 10% of all spinal fusion procedures. (See DuraSeal(TM) Spine Sealant Receives FDA Approval.)
DuraSeal, originally developed by Confluent Surgical, is a PEG (polyethylene glycol) solution and a trilysine amine solution, that has been shown effective in preventing intra-operative and post-operative surgical complications as a result of fluid, air and blood leaks. In 2005, the FDA gave approval for DuraSeal in cranial procedures.
The development of surgical sealants is moving increasingly toward internal use. Currently, most sealants are fibrin- or thrombin-derived and are effective at hemostasis, with sealing being a less significant function served due their need for greater strength in in adhesion. Cyanacrylate-based sealants might otherwise represent a viable alternative for internal sealing, but their toxicity has kept their use to predominantly topical applications.
Sealants like DuraSeal (HyperBranch Medical also makes a dural sealant, which has received CE Mark for Europe but is awaiting U.S. FDA approval) are making progress in demonstrating internal applications, albeit via adjunctive use (e.g., creating a seal along suture lines) rather than as stand-alone sealants.
Below is an overview of fibrin sealant and glue use and development (from MMD report #S175).
The terms “sealant” and “glue” tend to be used interchangeably in the surgical context, but in fact there is a difference in adhesive strength between sealants, pioneered by fibrin products (sometimes homemade) and the later, stronger glues of which cyanoacrylate-based products were the leaders.
Fibrin sealants represented a revolution in local hemostatic measures for both bleeding and nonbleeding disorders. Tourniquet, pressure and sutures have been used for controlling excessive bleeding during surgical procedures for hundreds of years. Fibrin sealant has the potential to provide life-saving control of excessive bleeding in many critical surgical operations and during a number of elective procedures. It is used for local hemostasis and as an augmenting material during arterial bleeding. It has been applied to every organ except eyeballs. It has been shown to be very useful for local hemostasis, a valuable tool for adhesion, sealing, anastomosis, vascular and nerve grafts, and many other procedures.
Fibrin and other sealant products have been approved and used outside the United States for many years and their use has created strong awareness of their surgical and economic benefits in Europe, Latin America and Asia. As a result, many such products have been marketed in these regions for up to 20 years and have been developed for a variety of surgical uses. While in the United States these products were approved initially as hemostatic adjuncts to suturing, they are increasingly being used for sealing of tissues, yet their use beyond hemostasis (i.e., as sealants and low-strength glues) lags that of markets outside the United States.
For the vast majority of surgical procedures, sutures and staples remain the most common methods of closure, but often they are sub-optimal. They do not have inherent sealing capabilities, and therefore cannot stop air and fluid leakage (for example in lung resection) and fluid leakage at the wound site. Furthermore, friable tissues such as the liver, brain or spleen, are fragile and often cannot support sutures or staples. Therefore, other means of wound closure are required for repair of these tissues.
However, the steady pace of FDA approvals and market introductions for products with sealing capabilities illustrates the success manufacturers have had in surmounting many of the technical hurdles to these products providing strong roles in tissue sealing. These include approvals by Baxter (Tisseel), Genzyme (FocalSeal), GluStitch (GluShield), Angiotech (CoSeal, Vitagel), CryoLife (BioGlue), and Syneture/Covidien (Indermil).
See MedMarket Diligence report #S175, "Worldwide Surgical Sealants, Glues and Wound Closure, 2009-2013."