Chronic cannabis use linked to ‘increased complications’ after spine surgery

The diagnosis of cannabis use disorder has been linked to higher complication rates in patients undergoing spinal surgery, in a new study.

According to researchers at the University of Illinois, Chicago, chronic cannabis consumption could mean surgical care may be ‘extremely complex and difficult’.

Lead author Dr Ankit Indravadan Mehta, believes chronic cannabis use among patients undergoing spine surgery is associated with “higher rates of inpatient neurovascular, thromboembolic, and pulmonary complications”.

Using a national hospital database (Nationwide Inpatient Sample), researchers at the University of Illinois at Chicago identified nearly 433,000 patients who underwent common elective spinal surgery procedures between 2012 and 2015. 

About 2,400 patients had a diagnosis of cannabis use disorder, defined as continued use of cannabis despite significant distress or impairment.

On initial analysis, there were some important differences between patients with and without cannabis use disorder. 

Patients diagnosed with problematic cannabis use were younger, more likely to be male, and had lower rates of accompanying medical disorders (comorbidity). They were also much more likely to use tobacco – about 71 percent compared to 31 percent.

Using a technique called propensity score matching, Dr Mehta and colleagues created matched groups of 2,184 chronic cannabis users versus non-users with similar characteristics and comorbidities. 

A wide range of complications and other hospital outcomes of spinal surgery were compared between groups.

Patients with cannabis use disorder were at increased risk for several types of complications after spinal surgery. 

The cannabis users were said to be around twice as likely to develop respiratory and blood clot-related (thromboembolism) complications. They also had nearly a threefold increase in the risk of stroke and other neurologic complications. Risk of bloodstream infection (septicemia or sepsis) was increased by 50 percent.

There were also more heart attacks among patients with cannabis use disorder, but on further analysis, this was related to their much higher rate of tobacco use.

Patients with cannabis use disorder also spent nearly two more days in the hospital and were more likely to be discharged to a nursing or rehabilitation facility and less likely to receive home health care.

The findings have important implications for anesthesia and surgical management in patients with cannabis use disorder, Dr Mehta and colleagues believe. 

Such patients may need higher doses of opioid medications to achieve adequate pain management after spinal surgery. That may lead to slower recovery, requiring longer hospital stays and more intensive rehabilitation that cannot be done at home. The researchers also note previous studies outlining the mechanisms by which cannabis use may lead to increased risk of respiratory, thromboembolic, and neurologic complications.

“This study reveals multiple aspects of perioperative care that are extremely complex and difficult in patients with cannabis use disorder,” Dr Mehta and coauthors write. 

“Their high-risk cardiorespiratory profiles combined with specialised anesthetic considerations [before, during, and after surgery] necessitate very unique preoperative management. We hope this research will lead to future prospective trials for specific interventions that could improve outcomes in this specific population.”

The results come as cannabis becomes increasingly legalised across the US, with estimates suggesting that more than 15 percent of Americans use cannabis. 

However, a recent study concluded that neither the enactment of medical cannabis legalisation laws nor the establishment of dispensaries in the US, are associated with any increase in cannabis use among adolescents.