Understanding the Possible Risks and Complications of Surgery

No surgery is risk-free, but understanding the possible complications can help you make better and more informed decisions. Possible risks include a reaction to anesthesia, postoperative pain, nerve damage, and infection. In severe cases, pneumonia, internal bleeding, and septic shock can occur.

Even so, severe complications are relatively uncommon, affecting only around 8% of surgeries. The risk is greatest among people who undergo emergency surgery, open surgery, or extremely long surgeries. People with obesity or who have a postoperative infection are also at risk.

Most postoperative side effects tend to be relatively minor and manageable, such as incision pain, sore throat (from intubation), or nausea or vomiting (from anesthesia).

This article describes the possible risks of surgery. including how your risk of complications is assessed and avoided. It also offers tips on how to talk to your surgeon so that you are fully informed about the benefits and risks of any surgery you are scheduled to undergo.

Postoperative Pain, Swelling, and Bruising

Surgical site pain, bruising, and swelling are considered normal parts of the healing process after surgery. The severity of these symptoms can be influenced by the surgery type, the size and depth of the surgical wound, and your general health.

Cold compresses used for 10 to 15 minutes several times per day can help ease pain, swelling, and bruising. Over-the-counter painkillers like Tylenol (acetaminophen) can also provide relief, while nonsteroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen) and Aleve (naproxen) are generally avoided due to an increased risk of bleeding and bruising.

For most procedures, your surgeon should be able to give a general estimate for when pain, bruising, and swelling should completely subside.

Anesthesia Reactions

Most problems that arise during surgery are the result of the surgery itself, not the anesthesia. Even so, there is a risk of anesthesia-related complications, particularly when general anesthesia is used.

When you undergo general anesthesia, your breathing muscles become partially paralyzed, requiring you be undergo intubation (a breathing tube) to aid with breathing. The most common side effects of this are a sore throat and nausea.

A more serious condition associated with general anesthesia and intubation is aspiration. This occurs when you inhale vomited food or fluids during surgery, which can lead to a potentially serious complication called aspiration pneumonia.

By following the preoperative instructions—namely stopping fluids and food the midnight before the surgery—you greatly reduce the risk of aspiration. Antiemetic drugs can also be given to reduce nausea and vomiting.

Intraoperative Injuries

While every effort is made to avoid accidents, they do occur during surgery. Arguably, the most common intraoperative accident is the perforation of the wall of an organ with a scalpel or other surgical tool.

In many cases, the perforation can be quickly fixed with minimal consequence. However, there are times when a perforation can lead to contamination of the surgical site. Examples include a bowel or gallbladder perforation in which exposure to feces or bile can lead to contamination and postoperative infection.

If a perforation accident occurs, the surgeon will quickly classify the wound as either "clean," "clean/contaminated," "contaminated," or "dirty contaminated." The classification helps direct the appropriate course of action to reduce the risk of an infection.

Bleeding Problems During Surgery

Some bleeding is expected during surgery, but bleeding beyond the normal amount (referred to as a hemorrhage) can make a blood transfusion necessary. If bleeding is severe enough, it can lead to a severe drop in blood pressure, hypovolemic shock, and even death.

The risk of severe bleeding varies by the type and location of the surgery. Delicate surgeries near major blood vessels pose the greatest risk (such as the removal of a cancerous tumor near the superior rectal artery). Depending on these and other factors, the risk of bleeding can be as low as 3% or as high as 45%.

The risk is greater with open surgery (involving a scalpel and large incision) than with laparoscopic surgery (also known as "keyhole surgery"). Stopping blood thinners like warfarin before surgery can also help reduce the risk of bleeding.

Blood Clots Caused by Surgery

A blood clot, also known as a thrombus, is a mass of blood that forms when platelets and proteins in the blood stick together. While clotting helps stop bleeding, it can cause major problems if a clot develops inappropriately and blocks a major blood vessel.

With surgery, the major concern is deep vein thrombosis (DVT) in which a clot develops in a major vein (usually the leg). If the clot breaks off, it can get lodged in the lung, causing a pulmonary embolism, or migrate to the brain, causing an ischemic stroke. Both are potentially life-threatening.

Most people are given a blood thinner like heparin after major surgery to reduce the risk of DVT. They will also be advised to get up and walk as soon as possible to increase blood circulation in the legs. Compression socks can also help.

Nerve Damage From Surgery

The human body is covered with a network of nerves that direct involuntary functions such as respiration and digestion to voluntary functions such as walking and talking. They also provide sensations such as warmth, pressure, and pain.

During surgery, it is possible to damage nerves. Minor nerve injuries tend to repair themselves, but major ones (particularly those nearer the spine) can cause major problems if severed or damaged. The problems can be even more severe if the brain or spinal cord is injured.

The consequences of surgical nerve injury are many, depending on which nerves are involved and how severely they are injured. Possible complications include:

• Numbness
• Peripheral neuropathy (pins-and-needles sensation)
• Chronic nerve pain
• Erectile dysfunction
• Loss of bowel or bladder control
• Impairment of mobility, speech, or vision
• Paralysis

Postoperative Infections

When the appropriate precautions are taken, the risk of surgical site infections (SSIs) is low. Still, they can and do occur.

Causes of SSIs during surgery include the accidental perforation of an organ or the accidental perforation of a surgical glove (exposing the surgical site to bacteria from the surgeon's finger). Most infections are due to improper wound care, often when a patient returns home.

If not treated with antibiotics, an SSI can spread to the bloodstream, causing septicemia. This, in turn, can trigger a potentially deadly, all-body reaction known as sepsis.

Postoperative Pneumonia

Most people can be removed from the breathing machine, called a mechanical ventilator, at the end of surgery. Some may require intubation and ventilation for longer, especially those who experienced severe trauma, underwent prolonged surgery, or have an underlying lung disease like COPD.

The problem is that longer ventilation times translate to a higher risk of pneumonia. Studies have shown that the risk of this increases exponentially when a ventilator is used for over 24 hours.

Staying in bed for three days without movement can also increase the risk of postoperative pneumonia. This is another reason why patients are encouraged to get up and move around as soon as possible after surgery, particularly if general anesthesia is used.

Delayed Healing After Surgery

Some people take longer to heal from surgery, particularly those with a chronic illness like COPD or a weakened immune system. People with obesity and uncontrolled diabetes can also take longer to heal due to abnormal changes in the metabolism and immune response.

Performance status (PS) also factors into how slowly or quickly a person recovers. This is a measurement used with certain surgeries to determine how able a person is to care for themselves. People with a high PS score tend to recover from surgery far faster than people with a low PS score.

Scarring After Surgery

Scarring after surgery is not always preventable, especially when a large incision or multiple incisions are made. This is one of the reasons why laparoscopic surgery may be considered as it reduces the size of the incision. Speak with your surgeon to see if this is possible.

Patients also have a significant responsibility in reducing their risk of scarring. Following wound care instructions not only reduces the risk of scarring but also the risk of infection (which can contribute to scarring).

If scarring is a concern, quitting cigarettes at least two weeks before surgery and during recovery can help. Smoking causes the narrowing of blood vessels throughout the body, slowing the healing process by depriving tissues of oxygen and nutrients.

Poor Results After Surgery

Not all surgeries achieve the expected outcome, and this should be discussed beforehand so that you have realistic expectations going into surgery. Surgical re-treatment is not uncommon, particularly with degenerative spinal diseases or following a severe traumatic injury.

In some cases, poor results cannot be prevented, especially if the problem is worse than anticipated once the surgery starts. Some surgeries have to be stopped if a person cannot tolerate the procedure, which can also affect the outcome.

Death Due to Surgery

All surgeries, whether elective or necessary, carry a risk of death. Some are exceptionally low, while others are significantly higher. The risk of death is higher with emergency surgery, major surgery on an elderly adult, or organ transplant surgery.

On rare occasions, some people might experience a severe reaction to anesthesia called malignant hyperthermia. This is a rare reaction thought to be genetic in origin that causes dangerously high fever, muscle spasms, a rapid heart rate, and possibly death.

Overall, the risk of death from general surgery is around 2.3%. The risk is significantly higher with emergency surgery and complicated major surgeries.

How Is Surgical Risk Assessed?

Before surgery, your surgeon will meet with you and explain the potential risks of your surgery. This process is called informed consent. This typically takes place several days or weeks before surgery.

One of the best ways to lower your risk of complications is to choose a surgeon who performs the procedure regularly in a facility equipped for that surgery. You should then be prepared to ask any or all questions you need to make an informed judgment.

Your surgeon can tell you more about your level of risk after these questions have been answered:

• What are the risks associated with this surgery?
• What are my risks as an individual?
• Am I a good candidate for the surgery?
• How often have you performed this surgery?
• How long will I be under anesthesia?
• What are the side effects of the anesthesia?
• How long will the surgery take?
• What can I expect immediately following surgery?
• How long will recovery take and what will it involve?
• Do the benefits of the surgery outweigh the risks?
• Are there alternatives to surgery?

Which Surgeries Are Considered High Risk?

Certain surgeries have a higher risk of complications than others. Of those that involve anesthesia, the risk can be broadly described as follows:

Certain factors also increase your risk of surgical complications, including:

• Older age
• Obesity
• Cigarette smoking
• Heavy alcohol use
• Pre-existing conditions like sleep apnea, high blood pressure, heart disease, lung disease, diabetes, and chronic kidney disease

Summary

All surgeries carry a risk of complications. The risk is influenced by the type of surgery you undergo, the duration of the surgery, the need for general anesthesia, and individual factors like your age, general health, and pre-existing conditions.

Possible risks of surgery include postoperative pain, pneumonia, blood clots, a reaction to anesthesia, surgical site infection, nerve damage, and surgical accidents. Speak with your surgeon beforehand to fully understand the risks and benefits as they pertain to you as an individual.