NSS is performed by many urologists endoscopically, and it has emerged as an alternative to radical nephrectomy for removal of small (≤4 cm diameter) as well as larger renal masses, since cancer-specific survival outcomes are similar for both approaches, even in young patients
[17, 18]. However, achieving rapid and effective hemostasis in NSS can be challenging. Fibrin pad was designed to provide surgeons an alternative adjunct to hemostatic techniques for achieving rapid control of mild, moderate, and severe bleeding in a variety of tissue types. In the current Phase I study, complete hemostasis was achieved in all patients within 3–4 min of a single application of the fibrin pad, without the occurrence of re-bleeding. This has immense clinical significance as it has been reported that each additional minute of warm ischemia following partial nephrectomy is associated with a 5% increase in the odds of developing acute renal failure, 6% increase in the odds of a glomerular filtration rate of <15 mL/min per 1.73 m2 in the postoperative period, and a 6% increase in the risk of new-onset stage IV chronic kidney disease during follow-up
. Technologies similar to the fibrin pad have been demonstrated to be effective in sealing air leakage in the lung
 and for achieving hemostasis in the kidney
 and liver
. TachoSilTM, an equine collagen patch coated on one side with human fibrinogen and thrombin, has been used in clinical trials; however, animal collagen could be a concern in allergic patients
In the Phase II study, where fibrin pad was used as the primary and sole hemostat, the upper limit of product performance was tested by assessing its efficacy in controlling severe arterial bleeding from the highly vascular renal parenchyma. Although hemostasis was achieved, all patients in the fibrin pad group required reapplication of the product. This may be attributed to the learning curve of surgeons and also to the fact that the fibrin pad requires direct and complete product-to-tissue surface apposition with persistent manual compression to activate the biologic components and develop tissue adherence, which may have been challenging given the irregular wound geometry. Intraoperative treatment failure was observed in all 3 patients in the SOC group, where vascular clamping was used. Since no vascular clamping was required in the fibrin pad group, the possibility of ischemia is minimal.
Fibrin pad builds on the EVICEL® liquid fibrin sealant technology consisting of virus-inactivated, human plasma-derived thrombin and fibrinogen
[15, 25]. The 2 components are mixed during application and upon combination, mimic the final step in the blood coagulation pathway to form a stable clot
[11, 26]. Furthermore, the biological components of the fibrin pad are free of tranexamic acid and aprotinin, which have been associated with neurological AEs and hypersensitivity reactions, respectively
[27, 28]. The fibrin sealant may be rendered ineffective if it is removed from the TBS due to adhesive or cohesive failure, particularly in severe bleeding
[12, 24, 29, 30]. In a prospective, randomized controlled trial that compared the safety and hemostatic effectiveness of a fibrin sealant (EVICEL®; 75 patients) to manual compression (72 patients) during vascular surgery, Chalmers et al. demonstrated that a higher percentage of patients who received the fibrin sealant achieved hemostasis at 4 min as compared to those who received manual compression (85% vs. 39%; P < 0.001)
, showing that biological components present in the fibrin pad are effective in achieving hemostasis.
While fibrin sealants have proven efficacy in intraoperative hemostasis, Cornum et al. evaluated the ability of an absorbable fibrin adhesive bandage (AFAB), a prototype product comprising lyophilized fibrinogen and thrombin on a VICRYL mesh backing, to seal the collecting system and control bleeding after partial nephrectomy in growing pigs
. Compared to conventional management, the use of AFAB resulted in significantly less bleeding (357 mL vs. 13 mL with AFAB; P < 0.001), shorter operative and ischemic times, a stable clot, and healing that is at least as successful as conventional treatments. A case series on the use of fibrin sealant applied over an absorbable hemostat, SURGICEL® after argon beam coagulation in 15 patients undergoing laparoscopic wedge resection of small renal lesions reported that hemostasis was achieved in all patients, and no blood transfusion was required
. These studies demonstrated that a combination of biological components on a bio-absorbable pad, as used in the current study, was effective for hemostasis.
Furthermore, a pre-clinical study in a severe renal bleeding swine model demonstrated that fibrin pad was as effective as conventional therapy in achieving durable hemostasis, and no case of re-bleeding or systemic/local adverse response was observed during the 8-week follow-up period