Deep Vein Thrombosis and Pulmonary Embolism (DVT/PE)
A DVT is a blood clot that forms in a vein, most often in the calf. As the heart is responsible for pumping blood throughout the body, the contraction of your leg muscles (especially while walking), acts like a secondary heart to essentially pump this blood back to your lungs and heart. While having surgery, or with being more sedentary before and/or after surgery, your leg muscles contract less vigorously and thus the blood tends to be pumped out of your legs less efficiently…in essence, it can pool (become stagnant) and a blood clot can form. This phenomenon can occur while sitting for an extended period of time on an airplane as well. Furthermore, during and immediately following surgery, your body attempts to stop bleeding associated with the surgery itself and therefore increases its clotting mechanisms.
- There are many risk factors for a DVT to form, in addition to surgery itself and the prolonged bedrest associated with it. This list includes, but is not limited to the following: pregnancy, tobacco use, obesity, past history of a DVT, family history of a DVT, diabetes, oral birth control and hormone therapy, among others.
- Pulmonary Embolus: A DVT forms typically in the calf and can extend upward. A piece of the clot can break off and go to the lung – this is called a Pulmonary Embolus (PE). A PE is a serious condition and warrants immediate attention, as does a DVT given its potential to cause a PE. A DVT presents most often with calf swelling and pain. A PE presents most commonly with chest pain and shortness of breath. There are variant presentations of both of these potentially dangerous conditions.
- Prevention is the key. Early ambulation/mobilization is critical in helping to prevent this phenomenon. Compressions stockings and compression stockings are used as well to decrease pooling of blood in the legs. Medications referred to as “blood thinners” such as low molecular weight heparin are often utilized in higher risk patients.
Wound Healing Problems
This is rare but possible any time an incision is made. Risk factors for wound healing problems include very advanced age, multiple prior procedures, infected tissue, diabetes, alcoholism, and poor nutrition/protein deficiencies, among others. Nevertheless, even in the face of these associated diseases, the risk of wound healing problems remains exceedingly rare.
An infection is a known risk of any surgical procedure, as the integrity of our main defense against the outside world – our skin – is violated. That being said, infections occur in less than 1% of spine surgeries and thus are quite rare. We take every precaution possible to prevent infection in the surgical setting to include IV antibiotics before and after surgery (and sometimes during surgery in longer cases) in addition to meticulous sterile technique.
- An infection can be superficial or deep. A superficial infection involves the skin and layer of tissue just under the skin called the dermis. A superficial infection often responds to a simple ‘by mouth’ antibiotic and local wound care. A ‘deep infection’ involves deeper tissue, typically at the level of the spine, possibly involving the disc, surrounding tissues, instrumentation if present, and sometimes bone. This type of infection is more serious, and requires IV antibiotics for a prolonged period of time, and sometimes re-operation.
- Superficial infections present with localized pain as well as redness, swelling, and/or warmth around the incision site . There can be drainage from the incision, often yellowish in color. The drainage can have a foul odor at times. A ‘deep infection’ presents with increased pain, and often yet not always, with fevers, chills, night sweats, and a feeling of fatigue/malaise.
The lungs, and specifically the smaller branches of the respiratory tree called ‘alveoli’ are where the primary gas exchange takes place – that is, oxygen from the air one breathes in (inhalation) is transferred to the blood and carbon dioxide in one’s blood is transferred to the air which is then breathed out exhalation). Atelectasis is a condition where this gas exchange is compromised, typically due to collapse of the alveoli. This collapse of the alveoli is often present in patients who have had surgery as they are less likely to take deep breaths and keep their lungs expanded. Reasons for a surgical patient to be at higher risk of atelectasis include pain that may inhibit deeper breathing, narcotic pain medications that can be sedating, and simply being much more sedentary. Atelectasis can decrease oxygenation of one’s blood which potentially can decrease alertness, healing from surgery, and most importantly, increase one’s chance of developing a pneumonia. Early mobility and use of an incentive spirometer (a device at the bedside that will keep your lungs active and inflated) are critical in trying to avoid atelectasis from developing.
Allergic Reactions and the Immune System
The immune system is the body’s natural defense system. It is essentially the system within one’s body responsible for identifying and protecting the body against invasion of foreign agents such as germs and microorganisms that could potentially cause disease. The immune system is made up of a well-coordinated system involving different cells, tissues, and organs. The main cells involved are called leukocytes, or white blood cells. These cells identify and attempt to eliminate certain foreign substances or organisms that harm one’s body or cause disease.
- Allergic reactions are simply an overreaction of the immune system. In an allergic reaction, the immune system’s response is often directed at foreign substances that are essentially harmless (e.g. pollen, dust mites, medications) yet the immune system perceives them as being potentially harmful. Symptoms can range from mild (such as itchiness, runny nose, sneezing, rash, nausea, and diarrhea) to severe (wheezing/shortness of breath, coughing, swelling of the airway, and even death). This latter more severe form of an allergic reaction is called ‘anaphylaxis’.
- Allergic reactions can occur in and around the time of surgery as one is exposed to a variety of substances and/or medications that perhaps are unfamiliar to the patient. Substances from the soaps used to clean the surgical site to tapes used to secure IV lines and bandages can potentially cause an allergic reaction. A variety of medications can cause allergic reactions, most commonly antibiotics and narcotic pain medications. Anesthetic agents have been implicated as well, although more rare. Latex allergy is a reaction to certain proteins present in natural rubber latex, a product made from a milky fluid found in the rubber tree. Latex is used in many types of surgical gloves as well as some other surgical products
- It is critical to let you doctor know if you have had a past allergic reaction to any of the above mentioned substances and medications so that appropriate precautions can be taken. The good news is that most allergic reactions can be avoided if you, the patient, have awareness of past allergic reactions. Furthermore, if exposed to a new substance that causes an allergic reaction, most commonly the reaction is mild and easily treatable with simple medications such an antihistamine and/or steroid. Other medications are used for more serious reactions.
Positioning Related Issues
Once you have been placed under general anesthesia, the surgical team led by the physician and physician assistant takes tremendous care in moving you safely from your pre-op bed to the operating table. As you are asleep, every effort is made by the surgical team to keep you in a comfortable position throughout the procedure and to properly pad any part of your body that could potentially incur discomfort and/or injury from a constant pressure while lying still for a prolonged period of time. Despite meticulous attention to positioning and extensive precautions taken on a routine basis, there are times that a muscle group can become bruised, a superficial nerve can become irritated (or even injured), or another pre-existing injury or problem can become aggravated. Following surgery, a vast majority of these issues resolve quickly and without long term problems associated. However, in rare cases and despite proper precautions being taken, more serious and/or long lasting issues may occur.
- Visual impairment/loss (‘ischemic optic neuropathy’) There exists an extremely rare and relatively poorly understood phenomenon in which patients undergoing surgeries involving prolonged prone (face down) positioning have developed visual loss. Research has been conducted to help identify several risk factors – that is, certain factors to watch carefully during surgery as there have been some associations made with this rare phenomenon. These involve blood loss, blood pressure management, length of surgery, and positioning. Despite the fact that there exists no clear ‘cause and effect’ relationship to these identified potential risk factors, the surgeon and anesthesiologist are well-aware of them, and do everything possible to minimize them. The risk has been estimated to be between 1 out of 60,000 to 125,000 surgical cases involving anesthesia. The risk is likely higher in spine surgery given the common prone (face down) positioning and occasional need for longer procedures, but fortunately, remains extremely low. Feel free to discuss this rare phenomenon with your surgeon.
Bowel obstructions can generally be divided into two categories. First, there exists a ‘mechanical’ intestinal obstruction in which there is a true barrier to movement of intestinal contents. ‘Mechanical obstruction’ causes include tumors, and even more commonly, adhesions (scar tissue from prior abdominal surgery). Second, there exists a type of intestinal obstruction called an ileus -- it exists quite commonly in the post-surgical population. Unlike a mechanical bowel obstruction, an ileus refers to a condition in which the motility (movement) of the intestines simply slows, or even stops. This temporary lack of forward movement of intestinal contents, leading to a temporary partial or complete blockage of the intestines, occurs for a variety of reasons that are complex and not fully understood. Symptoms of an ileus include abdominal discomfort and a sensation of bloating. Nausea and vomiting may occur and appetite is usually absent. Passing gas (flatulence) typically becomes rare or nonexistent, as does having a bowel movement.
- Treatment usually involves a ‘wait and watch’ approach as the condition normally resolves on its own. Supportive care includes Intravenous hydration and avoidance of any food or drink by mouth until the bowels essentially ‘wake up’. Reduction of narcotic pain medication use is helpful as these medications are known to slow motility. Other commonly considered remedies of varying scientific evidence and/or helpfulness include the following: early ambulation, placement of a nasogastric tube, gum chewing, and various medications to include suppositories and/or enemas.
Surgery does indeed involve an incision and dissection of tissue in order to approach the spine and perform the work necessary. The approach to the spine is often performed with an electrocautery device that destroys tissue using heat conduction from a metal probe heated by an electric current. This device can cut tissue as well as essentially burn smaller blood vessels to close them off thus preventing them from bleeding. Larger vessels need to be ligated, which means tied off with sutures. The overall risk of bleeding complications in spine surgery depends on a multitude of factors. These include the specific type of spine surgery one is having, the underlying health of the patient, the presence of underlying bleeding problems (coagulopathies) such as hemophilia, and certain medications one may be taking that “thin one’s blood”, or decrease the blood’s ability to clot.
- Although bleeding complications during and after spine surgery are relatively rare, they does exist a true risk. Surgeries that involve anterior exposure (from the front) to the thoracic and lumbar spine carry risk of injury to larger blood vessels such as the aorta and vena cava. Surgeries involving anterior approach to the neck also carry risk to larger blood vessels such as the carotid and/or vertebral arteries, as well as some larger veins. More extensive procedures such as deformity surgery (e.g. scoliosis and kyphosis and traumatic fractures) also carry greater risk of bleeding as more small vessels have the potential to ooze (slow bleed) at one time, and simply the procedure takes much longer. Although quite rare, a condition called disseminated intravascular coagulation (DIC) can occur in more extensive procedures, in which clotting factors become deficient and bleeding ensues.
- It is comforting to know that a vast majority of spine surgeries can be performed in a manner where blood loss is minimal and the risk of injury to a major vessel is minimized by meticulous dissection of tissue and excellent knowledge of the anatomy. As excessive bleeding can occur in rare cases, it is also comforting to know that the anesthesiologist is able to combat the negative effects of bleeding with a variety of IV fluids, often to include blood, thereby reducing the risk of a bad outcome.
- The patient should be aware that certain commonly used medication increase risk of intra-operative and post-operative bleeding. Be sure to discuss with your surgical team when to discontinue use of aspirin and aspirin products, as well as anti-inflammatory agents. Patients on anti-coagulation therapy or platelet inhibitors (e.g. heparin/lovenox, Coumadin, plavix etc…) must be sure to discuss this with the surgical team as well, as careful management and discontinuation is necessary. Finally, there are many alternative and natural medications known to increase risk of bleeding – again, be sure to discuss this with your provider.
- Following surgery, typically in the immediate post-operative period, there exists a chance that a vessel will start to bleed. Often the body is capable of re-absorbing this blood in the soft tissue. Occasionally, however, the blood can collect into essentially an expanding ‘water balloon’ called a hematoma. If the hematoma occurs in a place where there is no room for it, or if it expands, there is the possibility for it to put back pressure on structures such as nerves, or if in the thoracic and/cervical spine, the spinal cord. If in the cervical spine, a hematoma can put pressure on the airway (trachea) which can be quite serious. Most hematomas can be watched or treated with a relatively simple needle procedure called an aspiration (drainage). Occasionally, re-operation is necessary, potentially on an emergency basis depending on the situation.