They found widely different values for local blood flow [ 73 ], although the blood losses were not very different. This indicates that the effect on local blood flow is not the only factor involved.
The effect on blood flow in the epidural venous plexuses has also been hypothesized [ 74 ], and blood pressure by itself seems to be an important variable influencing blood loss [ ]. In the context of spinal fusions, some authors report that, since bleeding is mainly linked to bone decortication and is, therefore, essentially venous, blood loss will not be influenced by a decrease in arterial pressure [ 15 ]. Kakiushi [ 62 ] measured intraosseous pressure in thoracic vertebral bodies during surgery and found that the intraoperative blood loss correlated with intraosseous pressure but that the latter was not correlated to the arterial pressure.
Hypotensive anesthesia may lead to complications [ 81 ] and is contraindicated in some cases, mainly in patients with hypertension or ischemic disorders: The possibility of neurological damage at the level of already compressed and compromised nerve roots, where hypotension could add to the suffering of the root, was raised by Krengel et al.
The effect of hypotension on spinal cord function during scoliosis surgery has also been questioned [ 44 ]. However, although evoked potential monitoring may show temporary alterations, it does not appear that hypotensive anesthesia increases the risk of neurologic damage [ 45 ]. In this technique venous blood is collected at the beginning of the procedure, after the induction of anesthesia, in order to diminish hematocrit to a level around In children even lower values can safely be attained under 20 [ 33 , ].
The lost volume is compensated with synthetic colloids. Hemodilution can be combined with hypotensive anesthesia. Despite the hemoglobin loss, tissue oxygenation is maintained through increased cardiac output and better venous return due to reduced viscosity, shear and sludge effect. Furthermore, the loss of red blood cells is decreased, as the blood volume lost during surgery will contain fewer cells. The collected blood can then be retransfused according to need. Acute normovolemic hemodilution is widely used in spine surgery with good results in fusion [ 55 , 60 , 88 ], as well as in scoliosis surgery [ 11 , 24 , 30 ].
The patient can be kept in hemodilution beyond the surgical-procedure duration by delaying transfusion until the next day, with transfusion then being performed based on clinical judgment [ 55 ]. The main contraindications to this technique are ischemic disorders and hemoglobinopathies.
Local infiltration of paraspinal muscles with vasoconstrictors epinephrine, ornipressin is widely used in spine surgery. This is based on the common belief that vasoconstriction will decrease blood loss. However, the literature is very scarce, and there is little evidence of true efficacy [ 11 ]. Also, blood loss does not appear to be related to the dose injected [ 47 ]. Epidural blockade with normotensive anesthesia has been described as reducing blood loss [ 61 ].
It induces vasodilatation in the pelvis and lower limbs with a reactive vasoconstriction above the blocked level and, therefore, can only be used at the lumbar level. With this technique, blood lost during surgery is recuperated and processed through a pump system Cell Saver, Haemonetics , then transfused back to the patient. In this case it is scavenged blood that returns to the patient. It does not contain platelets or coagulation factors. Therefore, in the case of significant loss and return, a supplementation with fresh-frozen plasma is required [ 70 ]. This means that the need for homologous blood products is not entirely eliminated in this method.
It is estimated that about half of the lost red blood cells can be salvaged [ 37 ].
The main complication is that a dilutional or disseminated coagulopathy can occur, and there is also a question about the complete elimination of tissue residues. Cell saving is therefore contraindicated in the presence of coagulopathies. Other rare complications include pulmonary injuries probably linked to leukoagglutinins [ ] and transient hemoglobinuria [ 37 ]. This technique has been reported to be effective in spine surgery [ 10 , 77 , 84 ]. However, Copley et al.
They found that the first technique was more cost effective, decreasing allogeneic as well as autologous blood need [ 99 ]. In a meta-analysis, Huet et al. Postoperative collection and transfusion of either washed cell saving or unwashed blood has been described in many surgical fields. The most frequent technique consists of re-infusing filtered but unwashed blood from the wound-drainage systems. Many questions remain about the safety and real efficacy of this technique; e. The nephrotoxicity of free hemoglobin, originating from the hemolyzed red blood cells, poses a safety concern.
Furthermore, the efficacy of the filtering system on all tissue residues and metabolites is not entirely clear. Minor transient transfusion reactions may occur: Infection and malignancy are contraindications. This technique is very widely used in hip and knee arthroplasties. There are a few publications in the field of the spine, and these claim efficacy in reducing homologous transfusion requirements [ 10 , 84 ].
This is an antifibrinolytic agent that prevents plasmin from binding to fibrin. Some rare complications have been described: In the field of spine surgery there are scarce and conflicting results published. In a controlled but not blinded study [ 35 ] and then in a proper randomized controlled study against placebo [ 36 ], Florentino-Pineda et al.
In fusions in adults, Urban et al. In a Cochrane review on antifibrinolytic drugs in surgery, Henry et al.
In other reviews Kovesi et al. The complete mechanism of action of this substance remains unclear. It appears to decrease fibrinolysis by inhibiting plasmin, trypsin and kallikrein.
It also avoids pathologic platelet activation by stabilizing the platelet membrane. Finally, it seems to decrease the inflammatory response by inhibiting bradykinin, interleukin and TNF. Numerous problems are linked to its use: There also is a high risk of anaphylactic reaction after previous administration. This is especially important, as this drug is very widely used in cardiac surgery. In a multicenter randomized controlled trial, Samama et al.
A Cochrane review [ 48 ] of antifibrinolytic drugs in surgery found existing evidence for the use of aprotinin, despite biases in some of the reviewed studies. The use of aprotinin in spine surgery has been documented in a few controlled studies. Urban showed a decrease in blood loss and transfusion needs in adult fusion, and Cole et al.
This study demonstrated the decrease on intraoperative fibrinolysis through intraoperative dosage of D-dimmer. There are conflicting results as to the dose regimen to be used, with some reporting high dosage [ 78 , 94 ] and others half-dosage efficacy [ ]. This is an analog to L-arginine-vasopressin or antidiuretic hormone ADH. Its mechanism of action lies principally in an increase of the secretion of factor VIIIc. It also increases the secretion of von Willebrand factor vWF and has a paradoxical effect on the increase of plasminogen activator.
There are conflicting reports about the use of desmopressin in scoliosis surgery. In a controlled trial, Kobrinsky et al. The latter might be due to the decrease of bleeding in the wound. Other studies, however, do not confirm such findings. In neuromuscular scoliosis, where coagulation abnormalities are often present [ 63 , 89 ], leading to severe blood loss [ 31 ], Theroux et al.
Kovesi [ 68 ] concluded that it can be efficient in patients with a defect in platelet function but found no evidence for use in routine elective orthopedic surgery. A recent Cochrane review of DDAVP in surgery does not find any evidence for surgical use outside patients with congenital bleeding disorders [ 18 ]. Desmopressin might be well indicated in patients with von Willebrand disease, acquired platelet disorders, renal failure, cirrhosis or long-term salicylate treatment. Oestrogens have been widely used in the past for hemostasis.
However, their apparent lack of efficacy has made their use scarce [ 32 ]. The mode of action is unclear. They also have an antifibrinolytic activity by altering levels of factor V and decreasing the antithrombin activity of plasma. In a controlled study McCall et al. There were no side effects. In a review of systemic hemostatic drugs, Erstadt [ 32 ] found only limited efficacy of conjugated oestrogens in the reduction of blood loss in surgery.
Tranexamic acid decreases fibrinolysis by inhibiting transformation of plasminogen into plasmin.
Recent studies show efficacy in reduction of bleeding during hip- [ 76 ] and knee-replacement [ 56 ] procedures. Other studies, however, seem to show that tranexamic acid does not decrease hidden losses [ 40 ]. Meta-analysis of the use of tranexamic acid in surgery shows either specific efficacy in knee arthroplasty [ 32 , 51 ] or a trend towards effectiveness in other procedures, but results are marred by methodological flaws in the existing publications [ 48 ]. In the field of spine surgery, only one double-blind, placebo-controlled study in children and adolescents undergoing scoliosis surgery showed a reduction in transfusion needs without added complications [ 90 ].
This drug is an anti-hemophilic agent. Its efficacy on hemostasis in non-hemophilic subjects during surgery [ 4 ], neurosurgery [ 64 ] and trauma [ 43 ] has been reported. A double-blind randomized control trial has shown good results in prostatic surgery [ 39 ]. In spine surgery there are some anecdotal reports [ ] but there is currently a lack of evidence, due to a paucity of available studies [ 68 ].
This agent seems promising but true evidence of its efficacy in reducing bleeding during spine surgery has yet to be collected. Amino-acid infusion that induces thermogenesis prevented a drop in body temperature and decreased blood loss in hip arthroplasty [ ]. Likewise, aggressive warming to keep body temperature at There are no reports on the effect of warming during spine surgery.
Etamsylate Dycinone, Sanofi-Synthelabo , a drug marketed as hemostatic, was used without success in hip replacement [ 65 ], and no data on its use in spine surgery is available. Substitutive oxygen carriers are an elegant solution for the future [ 6 ]. Hemopure Biopure is already marketed in South Africa, although the ethical issues regarding the early commercial human use of such products are discussed [ 99 ].
It is a bovine stabilized hemoglobin for which an FDA regulatory filing phase III trial has been completed in orthopedic surgery including spine.
This study showed an important decrease in transfusion needs. There do not appear to be major safety issues [ ]. Hemolink Hemosol is a similar product but based on human hemoglobin. Results of phase II trials in cardiac surgery have been published showing decreased allogeneic transfusion needs with good safety [ 20 ]. A clinical phase III study, along the same lines, shows a marked reduction in the need for transfusions [ 42 ]. It acts in a purely mechanical way, by covering and filling bleeding bone surfaces.
Its best known use is probably the hemostasis of sternotomy surfaces. There have been few reports in the field of spine surgery. Use of bone wax to stop bleeding of the bony surface in the spine is hampered by the fear of leaving a foreign body that can intrude into the spinal canal. Indeed, Cirak and Unal describe a case of tetraplegia following use of bone wax [ 22 ]. Gelatin-based, local hemostatic agents have been used in surgery for decades.
They can be of bovine, porcine or equine origin and are available in multiple presentations: They can be used alone or soaked with thrombin. Gelatin-based devices have been reported to induce a better quality clot than collagen-based products [ 28 ]. The substance has been widely used in spine surgery, as it is considered safe to leave in the canal because it does not swell.
Some authors have even suggested that gelatin reduces scar adhesion [ 71 ]. However, several publications report severe neurological consequences including cauda equina syndromes linked to the use of gelatin products in the spinal canal [ 3 , 9 , 38 , 49 ]. Allergic reaction to gelatin after spinal use has also been reported [ 92 ]. Collagen based hemostatic products are from bovine, porcine or equine origin, and also exist in different forms: They should not be left in the spinal canal as they provoke adhesion formation and foreign body reactions.
A more elaborate product is Tachocomb Nycomed. It consists of a patch of collagen coated with fibrinogen and thrombin. In contact with liquids the components dissolve and the last phase of coagulation is launched, resulting in a fibrin-clot formation. That mode of action is similar to that of the fibrin sealants reviewed later. It also contains aprotinin in order to inhibit clot fibrinolysis. It is mostly used in thoracic and abdominal surgery, but repair of lacerations to the dural sac with this product have been reported [ 58 ] and experimental models have shown effectiveness in avoiding epidural fibrosis [ 73 ].
The use in spine surgery appears to raise the potential danger of leaving collagen-based agents in the spinal canal. These products also exist in multiple forms, such as sheets, gauze and powder. Their action is essentially a surface effect, which activates the initial coagulation phase. They also induce a moderate acceleration of fibrinogen polymerization. They should not be left in the canal, as they swell and cause foreign-body reactions.
Neurological complications have been widely reported [ 8 , 14 , 57 , 82 ]. Epidural migration, causing severe, and sometimes permanent, neurological lesions after use of cellulose hemostatic agents for thoracotomy have also been reported [ 98 , ]. 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. Achieving 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: 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. In 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 visualisation of eloquent structures and causing severe blood loss Fig.
A topical haemostat is the technique of choice as an adjunct to diathermy, to bone wax placed on bleeding bone and to the conventional clamping and tying of bleeders. Arterial bleeding, which is usually not manageable with application of haemostats, is only rarely encountered during most intraspinal extradural procedures. Mass effect of disc protrusion causes venous compression, which leads to dilated varicose intraspinal veins. These veins are the source of continuous bleeding, impeding visualisation of eloquent structures and can even cause severe blood loss.
This paper will focus on the application of absorbable porcine gelatine and regenerated oxidised cellulose. The favourable chemical properties of these haemostats have been reviewed elsewhere [ 2 ]. Given the plethora of a complicated intraoperative situation, we will discuss the most commonly encountered indications for haemostats during a standard intraspinal procedure: Most intraspinal procedures involve a more or less extensive removal of bone.
As bone is chipped away, the remaining bone and tissue tends to ooze. Bone wax is commonly used to stop bleeding from oozing bone. Though widely used, bone wax has some disadvantages. Because of its consistency it is often difficult to mold wax to the contours of the bleeding areas using a dissector. Recently, Surgifoam powder absorbable porcine gelatine, also: Spongostan powder has been introduced into the European market.
This haemostat forms a paste that can be spread or shaped to conform to irregular surfaces to stop bleeding fast. In contrast to bone wax, Surgifoam powder is easily moulded on the irregular surfaces of chipped bone. We prefer to apply a pea-sized portion of Surgifoam powder on the oozing surface and mould it into the bone after covering it with wet cottonoid patties Fig.
Bleeding will stop almost immediately. Residual Surgifoam powder may be removed by topical suction or irrigation. A Application of Surgifoam powder to control bleeding from oozing bone after partial laminectomy; B Surgifoam powder is easily applied on the oozing surface using a dissector and molded into the bone after covering it with wet cottonoid patty; C bleeding will stop almost immediately; D residual Surgifoam powder may be removed by topical suction or irrigation. Dissection of the dura from the lamina causes epidural venous oozing Fig. The use of bipolar cautery is limited, since dissipation of heat from the tips of the bipolar forceps may induce thermal injury to adjacent nerve roots or neural structures.
Though commonly used, the application of absorbable gelatine sponges in this setting has severe drawbacks. Blood-soaked gelatine tends to stick to surgical instruments. The introduction of regenerated oxidised cellulose Surgicel offers superior handling characteristics as compared to gelatine sponges. It is supplied as a knitted strip that can be easily trimmed to any size. Cut into small pieces, Surgicel conforms well to shapes, is easily manipulated and does not stick to instruments. The best way to prevent dislodgement by the suction device is to place a cottonoid patty on the Surgicel strip, thus enabling the surgeon to manoeuvre the haemostat, with the tip of the suction device, into the final position Fig.
Surgicel fibrillar is supplied as a layered, three-dimensional wafer with a consistency resembling cotton. Since the layers are peeled off in the desired amount, controlled placement of custom-sized pieces is facilitated.