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FloSeal — Flowable Gelatin-Thrombin Hemostatic Matrix

FloSeal is a flowable hemostatic matrix that combines bovine-derived cross-linked gelatin granules with a thrombin component to deliver a hybrid passive-plus-active hemostatic in a single syringe-based product. It is an adjunct for diffuse oozing on irregular surfaces (the renal bed after partial nephrectomy, the pelvic sidewall after lymphadenectomy, the retropubic space after complex reconstruction) when conventional hemostasis is ineffective or impractical.[1][2]

Composition and Mechanism​

ComponentRole
Gelatin matrix (bovine)Passive mechanical scaffold; contact-activates platelets; swells to fill irregular cavities
Thrombin (earlier FLOSEAL with pooled-plasma human thrombin, 500 IU/mL after reconstitution; current FLOSEAL with Recothrom, recombinant human thrombin from a Chinese hamster ovary cell line, 1,000 units/mL after reconstitution in the 5 mL kit or 588 units/mL in the 10 mL kit)[3]Converts fibrinogen → fibrin directly; bypasses the intrinsic/extrinsic coagulation cascade
Combined effectPassive matrix + active thrombin = local clot formation that still requires available fibrinogen; not treatment for systemic coagulopathy

Mechanism sequence​

  1. Syringe delivers flowable gel onto the bleeding surface
  2. Gelatin granules swell (approximately 20% in the 2016 human-thrombin IFU; 10–20% in the Recothrom IFU, maximal within about 10 minutes) as they absorb blood and tissue fluid.[3]
  3. Thrombin converts local fibrinogen to fibrin immediately, catalyzing clot formation
  4. Mechanical tamponade of the bleeding surface as the gel conforms to irregular anatomy
  5. Matrix resorbs over 6–8 weeks

GU Reconstruction Applications​

1. Partial nephrectomy renal bed​

The highest-yield application:[1][2]

  • Combined with sliding-clip renorrhaphy (suture hemostasis of the parenchymal bed)
  • With active renal blood flow restored after any hilar clamping, FloSeal may be back-filled into the actively oozing tumor excision defect when conventional control is ineffective or impractical; remove excess after hemostasis.[3]
  • May assist focal oozing control; routine reductions in warm ischemia time or transfusion are not established by the limited GU evidence cited here
  • Used in open and robotic partial nephrectomy; a dedicated endoscopic applicator is available for minimally invasive delivery.[3]

2. Pelvic sidewall / lymphadenectomy​

  • After pelvic lymph node dissection during radical cystectomy, prostatectomy, or deep endometriosis resection
  • For active capillary or small-venous oozing near iliac vessels or the obturator nerve, FloSeal may be used as a hemostatic adjunct when conventional control is ineffective or impractical; avoid vascular entry and remove excess after hemostasis.[3]

3. Retropubic space​

  • After complex bladder-neck reconstruction (Y-V plasty, complex pelvic fistula repair)
  • After radical prostatectomy when anterior urethral / puboprostatic ligament dissection has created a raw surface

4. Deep pelvic dissection​

  • Open presacral veins and venous plexi pose an intravascular uptake risk. Do not apply FLOSEAL at sites with negative peripheral venous pressure, and never inject or compress it into vessels.[3]
  • Pelvic sidewall after extensive dissection
  • Post-exenteration bleeding

5. High-risk patient populations​

  • Heparinized patients. Topical thrombin may assist local control, but anticoagulant effects are not universally bypassed
  • Coagulopathic patients. Local adjunct only; correct clinically important systemic coagulopathy in parallel
  • Radiated tissue. Where tissue quality is poor and standard suturing is unreliable

Preparation and Application​

Preparation and application​

Follow the specific kit IFU. Baxter's current US catalog lists FLOSEAL with Recothrom in 5 mL and 10 mL kits; the earlier human-thrombin kit had different mixing instructions and plasma-derived precautions.[1][3]

FeatureHuman-thrombin kit (5 mL IFU, rev. 2016)FLOSEAL with Recothrom (5 and 10 mL IFU, 2022–2023)
ThrombinPooled human plasma, vapor-heated and solvent/detergent treated; 2,500 IU vial in the 5 mL kitRecombinant human thrombin (CHO cell line); 5,000 IU vial in the 10 mL kit[3]
MixingReconstitute the thrombin, draw up 4 mL (5 mL kit), then pass between the gelatin and thrombin syringes at least 20 timesReconstitute the thrombin, draw 4 mL for the 5 mL kit or 8 mL for the 10 mL kit, then transfer between syringes for 10 passes[3]
Precaution specific to the thrombinHuman-plasma product: may transmit infectious agents (viruses, theoretically CJD; parvovirus B19 is hard to inactivate). Physicians should discuss the risk with the patient and report suspected transmissions to BaxterContraindicated with a history of hypersensitivity to Recothrom, its components or hamster proteins; may contain hamster or snake proteins; anaphylaxis possible

Both kits share the same timing and handling rules: reconstituted thrombin solution keeps up to 4 hours in the vial, the mixed matrix should stand 30 seconds before use, and the matrix is usable for up to 8 hours after mixing. Keep the syringes connected until needed so the product does not dry out.[3]

Application (both IFUs): identify the bleeding source, hold a gauze sponge moistened with non-heparinized saline against the surface, and dispense the matrix between the sponge and the tissue to make a small mound. For a crater, back-fill from the deepest point while withdrawing the tip. Maintain gentle sponge approximation for about 2 minutes without compressing the matrix in a closed space; then lift the sponge (irrigate it free if it adheres) and inspect.[3] If bleeding breaks through the granules, insert the tip through the mound and re-apply, then approximate again for up to 2 minutes. Once bleeding stops, irrigate and suction away the excess that is not incorporated in the clot, and do not disturb the clot complex.[3]

Remove antiseptics containing alcohol, iodine or heavy metals from the site first, because they denature thrombin. Do not cut the applicator tip, and do not clear the tip with air. Do not inject or compress the matrix into vessels or tissue, apply it while a vessel is clamped or bypassed (no active flow), use it prophylactically on a nonbleeding surface, close skin incisions with it, or use it in infection (caution in contaminated fields). Do not aspirate it into cell-salvage circuits or use it on bone that will receive acrylic cement. It is not a substitute for ligature or suture hemostasis and is not treatment for a primary coagulation disorder. The Recothrom IFU prohibits use to control postpartum bleeding or menorrhagia and advises use in pregnancy only when clearly needed.[3] The Recothrom IFU notes erectile dysfunction reported when FLOSEAL was used near the cavernous nerves during radical prostatectomy, and that excess left in place can mimic a recurrent mass on imaging or provoke a foreign-body reaction; it describes FLOSEAL as resorbed within 6–8 weeks and warns that excess gelatin-based hemostatic agents should be removed to avoid excessive inflammatory reaction, adhesion, or granuloma formation.[3]

Volume​

  • Kits are supplied in 5 mL and 10 mL sizes[3]
  • The volume needed depends on the size of the defect or bleeding surface; apply enough matrix to contact the active bleeding surface and remove excess after hemostasis.[3]

Advantages​

  • Active and passive combined. The thrombin component works locally, so the matrix can still form clot in anticoagulated patients; it does not correct systemic coagulopathy
  • Conforms to irregular surfaces. Flowable delivery reaches crevices inaccessible to sheet products
  • Trocar-compatible. Direct laparoscopic or robotic application
  • Parenchymal surfaces (renal bed, liver in GU-adjacent trauma)

Limitations​

  • Cost. FloSeal is a premium, thrombin-containing product and generally costs more than Surgicel or Arista (institution-dependent)
  • Swelling. About 10–20% expansion after application (10–20% in the human-thrombin IFU); can compress nerves or narrow spaces (use sparingly and irrigate meticulously near foramina, the spinal canal, or pelvic sidewall nerves)[3]
  • Bovine gelatin origin. A partial-nephrectomy case report described prolonged life-threatening gelatin-mediated anaphylaxis; its authors advised considering matrix removal during a reaction while weighing the risk of prolonged surgery.[4] FLOSEAL is contraindicated in known bovine-material allergy. The Recothrom kit also has hamster-protein and component hypersensitivity contraindications; the human-thrombin kit carries the plasma-derived infectious-agent precautions above.[3]
  • Not for intravascular use. Injection or compression into a vessel, or use with no active flow, can cause extensive intravascular clotting, thromboembolism and death
  • Preparation time. Reconstitution takes a few minutes.
  • Urinary-tract collecting-system contact. As with other hemostatic matrices, avoid direct contact with the urinary collecting system (stone nidus concern); the label states it should not be left in the renal pelvis or ureters

Evidence Base​

FloSeal's pivotal trial was in mixed surgical specialties against a gelatin sponge plus thrombin control; the manufacturer states that safety and effectiveness in urologic procedures have not been established through randomized clinical studies.[3] Urologic use rests on surgeon series and reviews.[2]

In a 2026 randomized trial of hemostatic agents as a class during robotic partial nephrectomy, 208 patients were randomized and 178 analyzed (88 no agent, 90 agent); postoperative day-1 mean hemoglobin decreases were 1.7 versus 1.8 g/dL (P=.5), estimated blood loss 116 versus 114 mL (P=.3), and major bleeding 4/88 versus 6/90 (P=.7).[5] A 2026 review of agents added to renorrhaphy (15 studies: 2 RCTs and 13 observational; 3,408 patients) found no demonstrated reduction in transfusion, hemorrhagic complications, or urinary leakage; certainty was moderate for randomized transfusion data, very low for observational transfusion data, and low for hemorrhagic complications, blood loss, and urinary leakage.[6] Consider FloSeal for residual diffuse oozing after suture or energy control when conventional hemostasis is ineffective or impractical, rather than using it routinely; the 2026 review found no studies evaluating a rescue strategy.[3][6]

See Also​

References​

1. Baxter. FloSeal current US product information and important risk information. Accessed September 11, 2026.

2. Msezane LP, Katz MH, Gofrit ON, et al. Hemostatic agents and instruments in laparoscopic renal surgery. J Endourol. 2008;22(3):403-8. doi:10.1089/end.2007.9844

3. Baxter. FloSeal with Recothrom product information. Formulation, preparation and safety restrictions. Also FLOSEAL Hemostatic Matrix 5 mL Instructions for Use (Baxter; human-thrombin kit, rev. 2016-11-01) and FLOSEAL Hemostatic Matrix 5 mL and 10 mL Instructions for Use with Recothrom (Baxter, 2022–2023): device description, contraindications, warnings, precautions, mixing, application, swelling and resorption.

4. McClintock G, Frishling D, Lam Y, et al. Prolonged life-threatening anaphylaxis to Floseal during partial nephrectomy: A case report. Curr Urol. 2025;19(3):198-200. doi:10.1097/CU9.0000000000000200

5. Lazarovich A, Tremblay S, Nottingham C, et al. Randomized, Prospective Evaluation of Hemostatic Agents in Robotic-Assisted Laparoscopic Partial Nephrectomy. J Urol. 2026;215(5):526-534. doi:10.1097/JU.0000000000004889

6. Shiomi da Cruz JA, De Souza Almeida A, Terada BD, et al. Adjunctive topical hemostatic agents combined with renorrhaphy versus renorrhaphy alone during partial nephrectomy: a systematic review and meta-analysis. World J Urol. 2026;44(1):592. doi:10.1007/s00345-026-06679-5