Ice Packs and Tylenol: Why a New Study on Post-Operative Pain Falls Flat

By Pat Anson, PNN Editor

The prescribing of opioids to patients recovering from surgery is a hot topic these days. Fearing that patients may become addicted, a growing number of U.S. hospitals now send their surgery patients home with non-opioid analgesics like Tylenol. According to a recent study, the number of opioid pills prescribed to patients for post-operative pain has been cut in half since 2017.

Reducing the use of opioids has led to complaints from patients that their post-operative pain is poorly treated. It may have even led to a tragic mass shooting. Police say the patient who killed four people – including his surgeon – at a Tulsa hospital this month was angry about “the ongoing pain that came from the surgery” he had 13 days earlier.

A new study by researchers at McGill University in Montreal is likely to add further fuel to the debate over opioids. In a meta-analysis of 47 clinical trials – a study of studies – researchers concluded that opioids don’t work well for post-operative pain, and cause more harm than good.

“The study results indicate that prescribing opioids to manage postoperative pain after discharge is not only unnecessary, but harmful in many surgical settings. These findings… fill a critical gap in knowledge about how pain should be managed at home after surgery,” is how a McGill University press release summarized the findings.

It’s important to read the fine print here. The McGill study, published in The Lancet, has three major limitations that the press release either ignores or downplays.

First, most of the clinical trials that were studied were for dental procedures such as tooth extractions or for minor surgeries conducted in a physician’s office, such as removal of a skin lesion. None of the surgeries involved patients having major operations in a hospital, such as a cesarean section or appendectomy.

Second, much of the data was “largely derived from low-quality trials,” according to the authors.

Third, the primary goal of the study was to assess the pain relief provided by opioids and non-opioid analgesics for one day -- “on day 1 after discharge” – which hardly fills the “critical gap in knowledge” about post-operative pain that McGill claims to have been filled. What about the next 5 or 10 days a patient might need to recover from surgery? What about 13 days?

Despite these glaring limits on the quality of their analysis, McGill researchers came to some broad conclusions.

"We found that prescribing opioids had no impact on patient-reported postoperative pain compared to simple over-the-counter analgesics, but it significantly increased the risk of adverse events, such as nausea, vomiting, constipation, dizziness and drowsiness," said lead author Julio Fiore Jr., PhD, a non-practicing “surgical scientist” at McGill University Health Centre.

"Prescribing opioid-free analgesia may prevent these adverse effects, improve patients' recovery experience, and also help mitigate the opioid crisis by reducing the risk of postoperative opioid misuse, addiction and diversion."

Study Methodology Questioned

But critics of the study’s methodology point out that most patients had only modest pain scores and received very low doses of opioids. The median daily dose of 27 morphine milligram equivalents (MME) is far below cautionary levels recommended by the CDC — and hardly reflective of what a patient might need after a major surgery.

“Most of the surgeries were minor and probably required minimal post-op analgesia,” said Stephen Nadeau, MD, a professor of Neurology at the University of Florida College of Medicine. “In short, the generalization of their findings to all opioid treatment of post-operative pain goes far beyond what the data will support. The reviewers and Lancet editor should have taken them to task about this.”

Over $80,000 in taxpayer funding for the McGill study came from the Canadian Institutes of Health Research, which is Canada's federal agency for healthcare research.

“This is typical of the research that we have seen from Canadian researchers that have put Canadians in such a bad state. Their methods and reasons are suspect and the use of data mining continues to come up with false premises,” said Barry Ulmer, Executive Director of the Chronic Pain Association of Canada. “It is shocking and McGill should be ashamed, as should The Lancet. What is also shocking is the Canadian government continues to fund many of these over the wall studies.”

In a preview of the McGill study published in 2020, Fiore and his colleagues said they would exclude from their analysis any studies that evaluated the effectiveness of analgesia for chronic postoperative pain. In other words, they excluded studies of pain relievers that had outcomes running counter to their narrative. If a surgery patient developed chronic pain after their acute pain was only treated with Tylenol, they didn’t want to hear about it.   

"The quality of the selected studies was variable, and none of them addressed non-opioid analgesia during discharge from major or major-complex surgery," acknowledged co-author Charbel El-Kefraoui, a non-practicing “research trainee” at McGill University. "It will therefore be important to conduct studies on different surgical procedures and on different postoperative pain management regimens, including pharmacologic and non-pharmacologic interventions like expectation setting, relaxation and ice packs."

Good luck with that. Ice packs and Tylenol are probably a good way to recover from a toothache, which is basically what the McGill study looked at. They are not a good way to treat acute pain from a major surgery. Or a way to avoid future tragedies like the one in Tulsa.