Commentary on: Efficacy, Security, and Manageability of Gelified Hemostatic Matrix in Bleeding Control during Thoracic and Lumbar Spine Surgery: FloSeal vs Surgiflo

In the current issue of Central European Neurosurgery, Landi et al present their experience with gelified hemostatic matrix for bleeding control during lumbar spine surgery.[1] The authors report using these hemostatics in 149 of 250 cases treated, almost routinely integrating the use of a gelatin matrix hemostatic in the treatment of arthritic or traumatic pathologies of the lumbar and thoracolumbar spine to achieve hemostasis. The authors are to be acknowledged for comparing the two main gelatin matrix hemostatic products available on the market and evaluating their efficacy and safety during spine surgery.

Achieving hemostasis during surgical procedures within the spinal canal is of paramount importance. Spinal surgery can result in substantial blood loss, which can raise various issues in the operating room such as limiting vision, lengthening procedure times, and increasing the risk for infection and mortality. Microsurgical approaches to intraspinal structures depend on clear visualization of the most delicate structures. Blood-sparing techniques are needed to control blood loss to prevent bleeding-related issues and the need for transfusions. Conventional blood-sparing procedures, such as cauterization and suturing, are in some cases either impractical, due to the risk of nerve injury, or ineffective because there is diffuse bleeding during spinal surgery. The mainstay of controlling intraspinal bleeding is bipolar cautery. It allows precise coagulation of small vessels and, compared with monopolar cautery, minimizes the dangerous spread of current to adjacent tissue. But the complete occlusion of the vessel lumen may compromise the perfusion of the neural tissue supplied by the cauterized vessel. Furthermore, dissipation of heat from the tips of the bipolar forceps may induce thermal injury to adjacent structures. Bipolar cautery is effective to occlude identifiable vessels, but it has minimal efficacy in controlling diffuse capillary bleeding from the epidural plexus. For these reasons, when applied topically, chemical hemostatic agents can control bleeding without occluding the vessel lumen, without causing thermal injuries to adjacent structures, and are in some cases preferable to bipolar cautery. For the local management of intraspinal/intraforaminal and perivascular bleeding, gelatin and collagen sponges are often used in combination with thrombin preparations, but the expansion of collagen sponges can compress and damage surrounding nerve structures. At the same time, removal of the sponges to prevent compression frequently leads to persistent if not worsening bleeding.

For many spine surgeons who routinely perform posterior open approaches to the lumbar spine, use of gelatin hemostatic matrix is a complementary alternative to classical hemostatic methods and materials, adding the benefit of a rapid hemostasis with a clear surgical field visualization.

The decision to utilize gelatin matrix agents is often made after consideration of alternative traditional hemostatic options including standard bipolar cautery and oxidized regenerated cellulose. Ideally, the surgeon should be capable of performing hemostasis using bipolar coagulation but can appropriately select and tailor any of these hemostatic techniques and materials for a given patient scenario because they all play useful and validated roles in the management of various types of hemorrhage.

Gelatin matrix-thrombin hemostatics have been demonstrated to be safe and biocompatible compared with the hemostatic agents currently in use. They are composed of a granular gelatin matrix derived from collagen cross-linked with glutaraldehyde. FloSeal (Baxter Healthcare, Deerfield, Illinois, United States)and Surgiflo (Ethicon, Somerville, New Jersey, United States) have been approved for clinical use by the U.S. Food and Drug Administration. They only differ in the source of collagen, coming from bovine and porcine derivatives, respectively. They are mixed with thrombin solution just before use, creating a compound that can be applied directly to the bleeding area to generate a thrombogenic clot.

The manner of gelatin matrix sealant preparation is similar for both Surgiflo and FloSeal. They have differently shaped gelatin granules: FloSeal is more granular and sticks well to the wall cavities of the operative cave. Surgiflo is more flowable, but flow characteristics, total volume, and consistency of the product can be altered by modifying the amount of liquid thrombin added.

In the neurosurgical literature, there are only a few reports of the use of gelatin matrix hemostatic agents in spinal procedures.[2] [3] [4] [5] I have used FloSeal and Surgiflo routinely for spinal and cranial hemostasis since they appeared on the market.[2] [3] [4] [6] I inject these agents with a long syringe tip in the bleeding area to control diffuse capillary oozing from the epidural space in some cases of posterior laminectomies where the source of bleeding is not visible because it originates from the torn epidural venous plexus underneath neural structures. The granular nature of the gelatin matrix enables the material to conform to any irregular surgical cave geometry. The hemostatic matrix is hydrophilic and adheres well to wet tissue, in contrast to other agents such as fibrin glue that need a dry surface. The granular gelatin particles conform to the bleeding site restricting blood flow and providing a mechanically stable matrix around which the fibrin clot conforms. Blood percolating through the spaces between the granules is exposed to a high concentration of thrombin and fibrinogen and converted into a fibrin polymer, resulting in a clot that remains in place at the tissue surface, providing a sealing effect at the bleeding site.

Although preclinical studies demonstrated that swelling following exposure to fluid is 11% for FloSeal and 7 to 20% for Surgiflo, compared with 135% for cellulose, 260% for collagen, and 320% for gelatin, I suggest carefully removing the excess granular material not incorporated in the hemostatic clot by gentle irrigation, without disrupting the hemostatic seal, thus reducing the volume of the gelatin matrix-thrombin solution mixture in the surgical cavity while maintaining hemostasis.

Our own clinical experience shows that the additional use of this product in the vicinity of the spinal cord and nerve roots is an efficient means of creating a dry and clear operating field, enhancing the safety of the operation while reducing its duration.

Another issue is that most intraspinal procedures involve a more or less extensive removal of bone, and as bone is chipped away, the remaining bone and tissue tends to ooze. Bone wax is commonly used to stop bleeding from oozing bone. Surgifoam powder (absorbable porcine gelatin, also Spongostan powder) was recently introduced into the European market. Bone wax and Surgifoam powder can be easily molded on the irregular surfaces of chipped bone and can effectively control diffuse capillary oozing. But of concern with hemostatic medications is the potential of thrombotic complications. One factor that may increase the thromboembolic risk is the presence of bleeding from bone spongiosa, so care must be paid to injecting gelatin granules with thrombin in the bone spongiosa, especially in cases of tumor removal or corpectomies.

Another potential concern when using any biological hemostatic agent is the risk of virus transmission. Although these are protein products, there has been no documented case of viral transmission through gelatin matrix hemostatic sealant to date. After evaluation in a multicenter prospective clinical trial, it was approved for clinical use by the U.S. Food and Drug Administration. Safety and biocompatibility after direct application of gelatin matrix hemostatics to neural tissue has been demonstrated in preclinical studies.

As discussed by Landi et al, the use of a more economical method to reach hemostasis in spinal procedures is mandatory. An exception can be made in selected patients where there is the need to shorten surgical time (e.g., older patients with a high American Society of Anesthesiologists score) or in which a two- or three-level laminotomy has been performed to reduce the postoperative risk of hematomas.

In addition to the time issue, one can also argue whether the time benefit of a gelatin matrix hemostat justifies the potentially greater costs of its use. A study protocol would be required, reflecting a variety of complex financial and international issues such as cost reimbursement in the different participating countries and the need for blood products. In the end, every surgeon has to decide what to use to achieve definitive hemostasis in spinal surgery.

The frequent use of these gelatin hemostats is not justified in the hands of a skilled neurosurgeon. For young spine surgeons and those starting their practice, the message is that FloSeal/Surgiflo represents a method for controlling difficult intraoperative situations and are of great value if not unduly used, but they should never be the primary option for achieving hemostasis.

In the case of intraspinal or epidural bleeding that characterizes most intraspinal pathologies, quick and safe hemostasis is mandatory to ensure adequate visualization and safe preparation, so as to avoid damaging nerves and spinal cord and to reduce the duration of surgery. The major benefits of gelatin matrix hemostatics are the efficient control of bleeding that is a prerequisite for the realization of the planned surgical aim and can thereby reduce perioperative morbidity. I agree with Landi et al that FloSeal and Surgiflo represent a safe and efficacious method for controlling difficult intraoperative bleeding.

• References

• 1 Landi A, Gregori F, Marotta N, Delfini R. Efficacy, security, and manageability of gelified hemostatic matrix in bleeding control during thoracic and lumbar spine surgery: FloSeal versus Surgiflo. J Neurol Surg A Cent Eur Neurosurg 2015. In Press. DOI 10.1055/s-0035-1558413
• 2 Gazzeri R, Galarza M, Alfier A. Safety biocompatibility of gelatin hemostatic matrix (FloSeal and Surgiflo) in neurosurgical procedures. Surg Technol Int 2012; 22: 49-54
• 3 Gazzeri R, Galarza M, Neroni M, Alfieri A, Giordano M. Hemostatic matrix sealant in neurosurgery: a clinical and imaging study. Acta Neurochir (Wien) 2011; 153 (1) 148-154 ; discussion 155
• 4 Gazzeri R, De Bonis C, Galarza M. Use of a thrombin-gelatin hemostatic matrix (Surgiflo) in spinal surgery. Surg Technol Int 2014; 25: 280-285
• 5 Renkens Jr KL, Payner TD, Leipzig TJ , et al. A multicenter, prospective, randomized trial evaluating a new hemostatic agent for spinal surgery. Spine 2001; 26 (15) 1645-1650
• 6 Gazzeri R, Galarza M, Neroni M, Alfieri A, Esposito S. Minimal craniotomy and matrix hemostatic sealant for the treatment of spontaneous supratentorial intracerebral hemorrhage. J Neurosurg 2009; 110 (5) 939-942