IntroductionAchieving haemostasis during surgical procedures within the spinal canal is of paramount importance. Whereas bleeding of up to one litre may be tolerated within structures such as the abdominal cavity, bleeding of only a few millilitres within the spinal canal may cause devastating neurological damage. In addition, microsurgical approaches to intraspinal structures depend on clear visualisation of the most delicate structures: continuous bleeding may impede identification of eloquent and/or pathological structures. Mechanical methods of haemostasis such as direct pressure and ligature are not applicable in intraspinal surgery because of the depth at which the surgery is performed and the indispensability of structures. For most of this century, the mainstay of controlling intraspinal bleeding has been bipolar cautery, allowing precise coagulation of small vessels, and, compared to monopolar cautery, minimizing the dangerous spread of current to adjacent tissue. Intraspinal, intradural and intramedullary bipolar cautery, however, has severe drawbacks. The complete occlusion of the vessel lumen may compromise the perfusion of the neural tissue supplied by the cauterized vessel. In addition, dissipation of heat from the tips of the bipolar forceps may induce thermal injury to adjacent vascular and neural structures. Though bipolar cautery is most effectively used to occlude identifiable vessels, it has minimal efficacy in controlling the diffuse capillary bleeding that characterises most intraspinal pathologies. For these reasons chemical haemostatic agents are often preferable to bipolar cautery in intraspinal procedures. These products can control bleeding without occluding the vessel lumen and cause no thermal injuries to adjacent structures. When applied topically, these agents can effectively control diffuse capillary oozing.
General remarksIn the majority of intraspinal, extradural procedures, bleeding is caused by venous vessels. This low-pressure bleeding will eventually stop when the patient is repositioned in the supine position and the intraspinal counter-pressure exceeds the intravenous pressure. However, due to venous compression, dilated varicose intraspinal veins may be a source of continuous bleeding, thereby impeding visualiAbstract There are various electrical, mechanical and chemical methods used to achieve haemostasis in spine surgery. Chemical haemostatic agents are often preferable to bipolar cautery in intraspinal procedures, because these products control bleeding without occluding the vessel lumen and cause no thermal injuries to adjacent structures. A topical haemostat is the often the technique of choice to control bleeding from bone and to diffuse capillary and epidural venous oozing. This paper focuses on technical aspects of the application of absorbable porcine gelatine and regenerated, oxidised cellulose. These haemostats have been used in neurosurgical intraspinal procedures for more than 30 years; however, new application forms like Surgicel fibrillar and Surgifoam powd...