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Surgical Haemostasis
Figure 1: Intra-operative View of Mini-open Anterior Lumbar
achieved by haemostasis through a variety of situation-dependent
Interbody Fusion Technique
methods. The more traditional haemostatic methods of clamps,
sutures and electrocautery can be used for direct cessation of openly
bleeding vessels. Bleeding from hard tissue originates from intra-
osseous vessels and cavities, which bleed when they are operated on
with chisels and punches. Such bleeds can be treated with bone wax,
although the high temperatures caused by high-speed drills without
irrigation can also seal cavities and vessels. Soft tissues and muscles
often bleed profusely with no clear source. In these cases, cautery or
chemical haemostatic agents are helpful. Clamps, cautery and suture
ligation are commonly used in the ALIF procedure, while cautery is
favoured in PLIF for intra-spinal work. Haemostasis is generally easier
to control in larger-scale surgeries; in microsurgeries, chemical
haemostatic agents have played an increasingly important role.
Although haemostasis can theoretically be compromised by
coagulopathies, these methods remain applicable to patients with
inherent or induced bleeding disorders. It is the responsibility of the
Figure 2: Intra-operative View of Posterior Lumbar
Interbody Fusion Procedure
physician to use the patient’s medical history to pre-empt any intra-
operative bleeding complications and administer agents accordingly
against heparin, coagulants or other medications. The meticulous
application of haemostatic adjuncts, whether traditional or chemical,
has demonstrated great utility in controlling intra-operative blood loss
and, in doing so, reducing a number of bleeding-related risks.
Controlling Haemostasis
Intra-operative bleeding can be mitigated by the use of hypotensive
anaesthesia and the positioning of the patient, although haemostatic
techniques will still be needed. Available chemical haemostatic agents
include oxidised cellulose, absorbable gelatine sponges, microfibril
collagen, saccharose and thrombin. These products vary in efficacy
and their utility is sometimes limited by aggressively bleeding sites and
difficulties in application. Thrombin is a critical plasma protein in
coagulation, activated by the intrinsic and extrinsic pathways, with the
ability to bypass the initial enzymatic steps of the coagulation pathway.
Not only can it cleave fibrinogen to form a fibrin gel, it can also directly
The Importance of Haemostasis activate the aggregation and adhesion of platelets to a wound. For these
Intra-operative bleeding poses problems to both the surgeon and the reasons, thrombin has been purified and used in topical control of
patient. Blood obstructs the surgeon’s view and may cause oversight of haemostasis for more than 60 years.
11
target pathologies. Any unplanned additional tissue damage due to
unexpected bleeding can prolong surgery and decrease its effectiveness, Gelfoam
®
(Pfizer) is an absorbable gelatine sponge that has been use
causing fatigue and stress to the surgical team. There are also in spinal surgery for more than 50 years, although its haemostatic
anaesthesiological risks to the patient due to destabilisation of vital properties are not fully understood. Prepared from porcine skin
parameters. Intra-operative bleeding also increases the chance of gelatine, the water-insoluble sponge is highly absorbent and resorbed
infection and scar tissue formation, thus creating a peridural fibrosis with into soft tissues within four to six weeks without forming excessive
ingrowth of fibrous connective tissue; the risk of revision surgery is also scar tissue. Though useable on its own as a haemostatic device, many
increased, for example to remove the compression-induced haematomas spinal surgeries frequently opt to use Gelfoam soaked in thrombin as
that may have formed. A decrease in post-operative haemoglobin and a topical haemostatic agent.
12
haematocrit levels is linked to the degree of intra-operative bleeds,
and can reduce a patient’s capacity to transport oxygen. Depending on A fairly new topical haemostatic agent is FloSeal™ (Baxter Healthcare),
the amount of blood lost, the patient may experience a range of a matrix of cross-linked bovine-derived gelatine and topical human
symptoms, including weakness, fatigue, hypotension, dyspnoea and thrombin. Where fibrin sealants require application to a relatively dry
tachycardia. If blood loss is extensive, blood transfusions become surface, FloSeal must be applied to actively bleeding sites due to its
necessary, posing health risks to the patient and financial burdens on the unique mechanism of action, upon which the gelatine granules swell
healthcare system. In short, intra-operative bleeding negatively affects and conform to the shape of the wound site, restricting blood flow by
patient outcome and can lengthen recovery time. a tamponade effect. The blood is then exposed to high concentrations
of thrombin at the surface of the gelatine granules, providing a stable
Blood loss in spinal surgery, as in any kind of surgery, must be carefully base for the fibrin clot to form around. The gelatine granules in
monitored and minimised to reduce the risk to the patient. This is the clot are resorbed into the body as the wound heals. Although the
38 EUROPEAN MUSCULOSKELETAL REVIEW
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