What Causes Chronic Postoperative Pain?

It is not unusual to experience pain after surgery. Considering that surgery involves cutting through bodily tissues, it seems normal that you would experience some degree of pain or discomfort after a procedure. Unfortunately, for some patients, postoperative pain does not go away after healing. For these people, ​chronic postoperative pain becomes a way of life.

There are a number of physical reasons why a person’s postoperative pain might become chronic, including nerve damage, scar tissue formation, tissue damage during surgery, and post-surgical complications, such as inflammation. Other potential causes of chronic postoperative pain include psychosocial ​factors and issues related to the surgery and recovery itself.

Physical Causes of Chronic Postoperative Pain

• Nerve Damage: Neuropathic pain, or pain caused by nerve damage or dysfunction, is one of the most common types of chronic postoperative pain. While surgeons take great care to avoid nerve damage during surgery, minor nicks and nerve stretching are sometimes unavoidable. Some examples of neuropathic postoperative pain include phantom limb pain and post-mastectomy pain.
• Scar Tissue: Scar tissue forms when the skin and tissues heal after surgery. Scar tissue may pull on the surrounding tissues, compress or irritate nerve endings, or actually have nerve cells trapped within it. All of these factors can lead to pain and discomfort around the surgical area. Scar tissue pain can become persistent after gall bladder surgery, also known as a cholecystectomy.
• Tissue Damage: Chronic postoperative pain from tissue damage is more common during orthopedic surgeries. Bone and soft tissues may be damaged or removed during a surgical procedure, such as a joint replacement, and this can lead to chronic postoperative pain.
• Wound Inflammation: Persistent wound pain is fairly common after cardiac surgeries; however, it is usually the least severe type of postoperative pain. Inflammation surrounding the wound can potentially lead to chronic pain, but there is little research available on this topic.

Psychosocial Associations With Chronic Postoperative Pain

The surgical procedure itself is not the only factor in chronic postoperative pain. Research has shown that a number of psychosocial factors may also contribute to persistent pain following surgery. These include:

• A higher level of pre-operative pain
• Pre-existing psychological conditions, such as anxiety or depression
• Fear or anxiety about the surgery
• Advanced age

Other Causes of Chronic Postoperative Pain

Chronic postoperative pain can also be caused by other factors during and after surgery. For instance, there is evidence that surgeries lasting longer than three hours are more likely to cause chronic postoperative pain. Additionally, certain types of radiation or chemotherapy treatments soon after surgery may increase the risk of developing postoperative pain.

Anesthesia management is another area being investigated for its role in preventing or inducing chronic postoperative pain. Though it is under investigation, regional anesthesia and prevention of acute breakthrough pain after surgery may decrease the risk of chronic postoperative pain. This is thought to prevent the nervous system from becoming sensitized after surgery.

Regardless of the cause of chronic postoperative pain, it is an issue for many people worldwide. Research is currently underway to determine the factors that might predict chronic postoperative pain so that treatment can be initiated early on.