Fibrin sealant helps to secure conjunctival autografts

May 15, 2005

Philadelphia—Fibrin tissue adhesive (Tisseel VH Fibrin Sealant, Baxter) is a safe and effective modality for securing autologous conjunctival grafts during pterygium surgery and offers many advantages for the surgeon and patient compared with suturing, said Sadeer B. Hannush, MD, attending surgeon, Cornea Service, Wills Eye Hospital, and assistant professor of ophthalmology, Jefferson Medical College, Philadelphia.

Dr. Hannush presented his experience performing the sutureless conjunctival transplantation technique in 47 consecutive eyes undergoing lamellar keratectomy for pterygium excision with autologous conjunctival transplantation. During follow-up that ranged between 1 and 27 months, 45 grafts remained completely in place, there were two partial graft retractions, and one partial recurrence, reported Dr. Hannush during the joint annual meeting of the American Academy of Ophthalmology and the European Society of Ophthalmology last year.

"Lesion excision with conjunctival or amniotic membrane grafts is the preferred technique of cornea specialists for pterygium management because it decreases the rate of recurrence compared with simple excision. However, sutures to secure a conjunctival graft cause irritation that can lead to patient discomfort and potentially unplanned office visits," Dr. Hannush said.

Gaining ground He noted that the fibrin sealant has been widely used in dermatologic and general surgery applications, but employed less often in ophthalmology. However, there have been several published reports describing its use in various ophthalmic procedures, including for fixing amniotic membrane transplants, lamellar grafts, and conjunctival autografts in the realm of corneal surgery.

To secure the conjunctival autograft, Dr. Hannush follows the manufacturer's directions for preparing the sealer protein solution and thrombin solution components. Then he sets the conjunctival graft epithelial side down on the cornea, puts one drop of thrombin solution on the scleral bed, one drop of the sealer protein solution on the underside of the conjunctival graft, and flips the graft over into place so that the two components of the fibrin sealant are mixed together directly on the tissue.

"When the two components come together, they begin to form a coagulum within about 7 seconds that solidifies within 3 to 5 minutes. Mixing the components together on the eye rather than externally affords me greater control of when they come into contact and how quickly the graft adheres," Dr. Hannush said.

He acknowledged that because the components of the fibrin sealant are derived from human and bovine sources, there is a theoretical risk of viral and prion disease transmission.

However, the manufacturer employs a rigorous screening protocol to reduce the chance of at-risk donations entering the plasma processing pool. The product then undergoes vapor heat viral inactivation. The fibrin sealant product has been associated with an excellent safety record to date.

"With about 12 million units of the fibrin sealant having been used over the past 20 years, there have been no documented transmissions of HIV; hepatitis A, B, or C; Creutzfeldt-Jakob disease; or bovine spongiform encephalopathy," Dr. Hannush said.

During the history of the product's availability, there have been two cases of transmission of HPV ±9. However, both occurred prior to the institution of viral PCR screening of donated plasma.

"While critics may argue that it is better to use sutures than to expose patients to any infectious disease risk, my experience has been so favorable and this product has been used so widely with such great safety in other fields of medicine that I think its benefits far outweigh any theoretical risk," Dr. Hannush concluded.