Risk for Relapse in MS Not Elevated by Exposure to Invasive Surgery Requiring Anesthesia

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Patients with multiple sclerosis are not likely to have an increased risk for relapse after having surgery requiring anesthesia challenging long-standing assumptions for people with multiple sclerosis and could inform clinical decision making.

Patients with multiple sclerosis (MS) are not likely to have an increased risk for relapse after having surgery requiring anesthesia, according to a study published in Multiple Sclerosis Journal. These findings challenge long-standing assumptions for people with MS and could inform clinical decision making moving forward.

Relapses in MS are a concern for patients and providers, and previous assumptions regarding the risk for relapse due to anesthesia and surgeries can often delay necessary procedures. This retrospective chart review used data extracted from patients’ medical records at the University of Michigan Multiple Sclerosis Center from January 2000 to July 2016 to determine whether the risk for relapse increased postoperatively. Researchers used conditional logistic regression to estimate within-patient unadjusted and age-adjusted odds of postoperative relapse vs preoperative relapse.

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The researchers identified 12 postoperative relapses among 281 patients (mean age, 49 years [SD=9.9, range=18-75], n=239 white, n=209 women, n=230 non-smokers, n=176 relapsing MS) who underwent 609 surgeries (n=311 major; n=299 minor). None of the surgeries were excluded for infection. Odds of postoperative vs preoperative relapse were not increased in either the unadjusted models (OR, 0.56; 95% CI, 0.18-1.79; P =.33) or age-adjusted models (OR, 0.66; 95% CI, 0.20-2.16; P =.49).

Patients identified as having postoperative relapse were significantly younger (39±8.8 years) and had more enhancing lesions on preoperative MRI (n=6 yes, n=3 no [113 patients had missing MRI data]). Crude estimate of annualized pre- and postoperative relapse relapse rates was 7.1% and 5.5%, respectively. Relapse odds did not differ significantly when adjusting for age and other between-patient variables.

Limitations of the study included identifying an older population of patients and cases where procedures occurred within a 90-day window (relapses occurring after 90 days or identified at other institutions were missed). Further, this study lacked the power to find a risk increase less than 2 times greater than baseline.

According to study investigators, “These findings suggest that [patients with MS] are unlikely to be at increased risk of relapse following surgery requiring anesthesia. Although larger, confirmatory studies are necessary, our data challenge long-standing assumptions regarding postoperative relapse risk for individuals with MS and could inform decision making.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


De Lott LB, Zerafa S, Shedden K, et al. Multiple sclerosis relapse risk in the postoperative period: Effects of invasive surgery and anesthesia [published online June 25, 2019]. Mult Scler. doi: 10.1177/1352458519860304