conley6.gif (2529 bytes)


Is Pain Hereditary?
A peek into how genetics and chronic pain are perhaps related


April 2018

When I was 17, I had all four of my wisdom teeth removed at once. Three were impacted. I had watched friends endure the same surgery, flush with swollen faces and painful tales, but I experienced no such discomfort. In fact, I didn’t swallow a single painkiller. And, when my mother had her knee replaced in her 80s, she told me she felt pain but not nearly as severe as what she was told to expect, and the pain didn’t live up to the hype again when my eldest son had his wisdom teeth removed last year. I wondered why we all got off so lightly. (Believe me, we aren’t any tougher than anyone else.)

Now, I may have my answer. According to Anesthesiology, an online medical journal published by the American Society of Anesthesiologists, genetics may determine how a patient experiences postoperative pain.

Carried out by researchers at the University of Hong Kong, the study indicates that certain common genetic variations could show whether a person is at high risk for developing chronic pain after surgery. Furthermore, researchers say these findings help explain why only a fraction of patients experience persistent pain.

“Interestingly, there are studies that indicate a patient’s response to various pain medications can also be tied to genetic factors,” notes Dr. Mark Zimmerman, an anesthesiologist with Midwest Orthopedic Specialty Hospital.

Chronic postsurgical pain is both a common and serious complication. The University of Hong Kong study notes that as many as 80 percent of patients suffer postsurgical chronic pain, and its authors estimate that millions of patients worldwide suffer from pain near the surgical wound for months — and even years — after surgery.

To confirm (or deny) these estimates, blood samples from more than 1,150 surgical patients were evaluated for the study, which examined genetic variations in 54 genes shown to be associated with pain sensation. One year postsurgery, patients were asked if they had experienced chronic pain around their surgical wound, and then rated the pain using a scale from 0 (no pain) to 10 (worst pain imaginable). Twenty-one percent of patients reported chronic postsurgical pain, and 33 percent rated their pain as severe. A gene found in the nervous system, known as brain-derived neurotrophic factor, was found to be most associated with increased chronic postsurgical pain. The study concluded that genetic variations of these genes accounted for a percentage of chronic postsurgical pain — between 7 and 12 percent, to be exact. This figure was notably higher than the 3 to 6 percent finding that had been determined by evaluating clinical risk factors, such as sex, age or smoking history.

Genetics or not, doctors have spent years learning to deal with how differently patients react to pain. “There are several ways to get a feel for a patient’s pain tolerance and threshold when first treating them,” explains Zimmerman. “First, it is important to take a thorough pain history for the patient and review what medications he or she is on. The patient’s reaction to preoperative procedures, such as perineural block, is very instructive as to the patient’s pain threshold. For instance, some patients don’t even notice the placement of the needle, while others exhibit high levels of discomfort and require large amounts of sedation.”

Intraoperative factors — like respiratory rate, heart rate, blood pressure and electroencephalogram (EEG) readings — are also closely monitored. “Together they give an indication of how the patient is physiologically handling noxious stimuli when unconscious,” says Zimmerman. “While these indicators are not perfect, they usually give an accurate picture of how the patient will handle postoperative pain.”

Zimmerman recently took care of a patient who reported almost no postoperative pain following major spinal surgery and hardly received any pain medication. Just before that, he had been with a patient who had undergone a similar procedure, required a large amount of pain medication, and still rated her pain as a 10. “This necessitates the use of different types and amounts of medication. The large amount of variability requires very careful planning,” Zimmerman adds. And in the future, a genetic test may help in that planning.

Midwest Orthopedic Specialty Hospital (MOSH)

MOSH is ranked one of the top 10 hospitals for patient satisfaction in likelihood to recommend the hospital, according to the Hospital Consumer Assessment of Healthcare Providers and Systems data compiled by the Centers for Medicare and Medicaid Services. The hospital was also named among the top 10 percent in the nation for orthopedic services and for joint replacement. That’s because the state-of-the-art facility was designed with you as the highest priority. It is just the right size: big enough to provide you with the best physicians and technology, and small enough to treat you like you’re the only patient.

Orthopedic Institute of Wisconsin

The Orthopedic Institute of Wisconsin offers advanced orthopedic care and state-of-the-art treatment to individuals faced with painful bone, muscle, tendon and joint cartilage disorders. A multispecialty continuum of care includes diagnosis, treatment, rehabilitation, education, prevention and follow-up from board-certified/eligible physician specialists — each fellowship trained in a specific area of orthopedic care, including hip, knee, shoulder, spine and back, foot and ankle, hand and upper extremity, joint replacement, sports medicine, trauma and work-related injuries. With locations in Brookfield, Milwaukee, Wauwatosa and two in Franklin, the Orthopedic Institute of Wisconsin offers nearby comfort and convenience. Office appointments available within 24 hours. Call (414) 384-6700 to schedule at any of the five locations.

Spine Pain Diagnostics Associates

Spine Pain Diagnostics Associates is an independent group of highly-trained physicians who specialize in interventional pain medicine, a unique specialty that focuses on diagnosing and treating pain.

Once the physicians have determined the source of pain, they treat it using minimally invasive procedures and techniques. These procedures are outpatient based and typically have very little downtime. If you are searching for pain relief, call the main office at (888) 724-6377 to schedule your appointment today.


This story ran in the April 2018  issue of: