In any surgical procedure there is a degree of blood loss, but the more invasive back surgery, such as a traditional open laminectomy, will cause more significant blood loss than a microlaminoforamintomy, for example. The main reason for the difference in blood loss is the degree of muscle trauma involved in the back surgery. Where spinal muscles need to be cut to allow the surgeon access to a larger section of the spine there will be greater blood loss than when these muscles are pushed aside by tubular retractors in a microsurgical procedure.
Back surgery using an anterior approach has a higher risk of blood loss and complication due to the presence of major blood vessels such as the aorta, and vena cava. Many surgeons favor a posterior approach in order to avoid these risks, especially in cases where a skilled vascular surgeon is not on hand to assist. Surgery for scoliosis and other major conditions also causes higher volume blood loss. Bleeding that continues post-surgery is liable to cause the patient to feel weak and further surgery may be necessary if the bleeding does not stop of its own accord. Efforts are made in every surgery to minimize blood loss, with blood vessels moved aside as carefully as possible to allow surgical access. Minimally invasive surgeries are at a distinct advantage over the extensive open procedures traditionally used for spinal surgery as regards bleeding and complication.
Medication and Blood Loss from Surgery
Many patients will be on medications such as aspirin, ibuprofen, or Warfarin prior to back surgery and these are likely to need discontinuing for a short time before their operation. Ensuring that the physician or surgeon is fully aware of all of the medications currently taken can help reduce the risks associated with back surgery. Prescribed and non-prescribed medications can affect the way that the blood clots, and alternative remedies are also implicated in this mechanism. Patients may be taking fish oil, white willow, or other remedies for pain, and these, along with herbs such as ginkgo biloba, and garlic can affect clotting of the blood and its viscosity.
Thrombophlebitis from Back Surgery
Thrombophlebitis is another concern for anyone undergoing back surgery. The risk of thrombophlebitis increases with the use of general anaesthetic as the patient is immobile for longer and circulation can become sluggish. Blood clots may form in the deep veins of the legs as circulation slows down and blood is not readily returned to the heart. This is also a risk when sitting on a cramped aircraft for many hours, and even when extremely sedentary at an office desk. Clots that form in the calves can lead to clots in the thighs and pelvis. These clots may then block the veins and cause ischaemia (loss of circulation) in the tissues of this area with necrosis occurring. If the clot (or a portion of it) breaks away and travels through the circulation it can become lodged in the blood vessels of the heart where it may cause ischaemia and a myocardial infarction (heart attack). Similarly, tissue death in the lungs can occur if a blood clot creates an embolism in the narrow blood vessels of the respiratory system. Stroke may occur if the clot travels to the brain, with tissue death and severe impairment possible.
The risk of deep vein thrombosis is higher with surgery as the body increases its clotting factors due to blood vessel injury. Direct blood vessel trauma such as pulling or stretching can also trigger the clotting process as can stagnant build-up of blood in the deep veins due to disuse during surgery. The use of drugs to reduce clotting may be advantageous during surgery to prevent thrombophlebitis occurring, but these an also increase the risk of excessive bleeding making it a fine balancing act on the part of the surgeons.
Wearing pressure stockings (similar to flight-socks) during surgery can aid the circulation from the deep veins and reduce a patient’s risk of blood clot formation. Similarly, having back surgery under a local rather than a general anaesthetic reduces the risks as the patient may be able to keep the muscles of the legs mobile and prevent stagnation of the circulation; these patients will also be ambulatory much faster after surgery, further reducing the risks. It is also important for patients to stay hydrated in order to lower the risk of problem clot formation and patients are advised to drink plenty of water following back surgery and become mobile as soon as is recommended. While a patient is in bed after back surgery they can do exercises such as pumping the feet up and down to encourage circulation; this works by contracting the muscles in the calf and squeezing the veins. Aspirin or heparin shots may also be used to reduce the risks of blood clots and thrombophlebitis, and vitamin E may also be beneficial in dissolving blood clots (although this is unlikely to be used in many hospitals). Lovenox is a relatively new medication that is injected twice a day in order to slow the clotting mechanism and Coumadin may be given orally if a longer term effect is required.
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