The approval of commercial human fibrin glue as a sealant and adhesive agent for “colostomy closure, coronary bypass surgery, and splenic repair” by the Food and Drug Administration in 1998 has led to its increased, albeit off-label, use in aesthetic surgical procedures to minimize ecchymosis, edema, and hematoma and to eliminate the need for dressings, garments, and drains. Our clinical cosmetic experience is similar to that of other American surgeons and and worldwide, and where commercial and autologous fibrin glue have been used extensively for more than 20 years.Since its introduction, the tensile clot strength of fibrin sealant has depended on both its fibrinogen concentration and the number of -cross-linkages present, whereas clot persistence was related to its rate of degradation. In this article we evaluate different concentrations of thrombin (setup times), fibrinogen (tensile strengths), and duration of adherence by varying their concentrations in subperiosteal and subcutaneous planes in Holtzman rats, and we support and encourage extension of the current use of human fibrin glue.

The experimental protocol was approved by the Medical Animal Care and Use Committee of the Huntington Medical Research Institute (Pasadena, CA). The fibrin sealant Hemaseel APR (Haemacure Corp., Sarasota, FL), was prepared immediately before its use under the dissected rat flaps. The prepackaged 2-mL Hemaseel kit consisted of 4 vials containing 4 key components: a human sealer protein concentrate (dried powder), a bovine fibrinolysis inhibitor (aprotinin) solution, human thrombin (dried powder), and calcium chloride solution. The sealer protein and fibrinolysis inhibitor were heated at 37°C for 10 minutes and then stirred together for 10 minutes until fully dissolved. If the sealer protein concentrate was not immediately used, the solution was kept at 37°C without stirring. The calcium chloride solution and freeze-dried thrombin were combined and swirled briefly together, then kept at 37°C until used. Sealer and thrombin solutions were placed in separate syringes and fitted into the Duploject System (Hyland Division, Baxter Laboratories Corp., Glendale, CA), which permitted equal volumes to be simultaneously mixed on delivery to the tissues. Although the dual syringe may be connected to a pressurized nitrogen-gas tank to aerosolize the glue into a fine mist for delivery, a standardized amount of the viscous material (0.5 mL/scalp pocket, 1.0 mL/abdominal pocket) was instilled with a syringe and massaged into 1 of the paired surgical pockets of the rats. Three different preparations of the above 2-component fibrin sealant from the Hemaseel APR kit were formulated with the preparation techniques described above:

1. Standard fibrin sealant (fibrinogen 75-115 mg/mL, thrombin 500 IU/mL)

2. Half-fibrinogen (fibrinogen 37.5-57.5 mg/mL, thrombin 500 IU/mL)

3. 1/100 thrombin (fibrinogen 75-115 mg/mL, thrombin 5 IU/mL).

Calcium chloride (40 mol/mL), aprotinin (3000 kallidinogenase activator), and factor XIII concentrations were kept constant in all preparations.

Experiment 1

Six male Holtzman rats weighing between 350 and 400 g were used in the first part of this study. Each animal was anesthetized with intraperitoneal sodium pentobarbital (30 mg/kg body wt) and premedicated with 6000 U flocillin. Each animal’s scalp and abdomen was shaved, prepped with hexachlorophene soap, and the rats were restrained sequentially in the supine and prone positions. Paired adjacent standardized pockets were designed on the scalp between the ears (1.5 × 3.0 cm) and on the abdomens (2.0 × 4.0 cm) of 6 rats. A small transverse 1.0-cm incision was made l.0 cm behind the midline marking to permit subperiosteal dissection of each set of paired scalp pockets and subcutaneous dissection of each set of paired abdominal pockets, separated by a retained septum. One of the 3 fibrin glue preparations was instilled blinded under 1 of the paired scalp and abdominal pockets in 2 of the 6 rats. After the fibrin glue was massaged evenly within the treated pocket, a needle was inserted in the septum between each of the paired flaps to centralize and stabilize the tissues during displacement readings. An Extech Digital Force Gauge (model 47504; Extech Instruments, Waltham, MA) was used to repeat 3 measurements of grams of tissue tension required to displace a central tattooed skin point on each scalp flap by 5 mm and on each abdominal flap by 10 mm. The opposite untreated pocket served as the time-matched control. We obtained measurements of the elevated flaps before instillation of glue, 15 and 30 seconds after glue application, and at 1, 5, 15, 30 and 60 minutes. One-way analysis of variance and Tukey’s test were used to calculate the mean values within the treated and control groups.