For a study, the researchers sought to look at the frequencies of postoperative complications in multiple sclerosis (MS) patients who have primary PLF and the economic burden associated with these surgeries in MS patients versus non-MS patients. Between 2006 and 2013, a retrospective evaluation of the Medicare database was undertaken on all patients who received PLF and posterior lumbar interbody fusion. The study eliminated cases involving same-day anterior or revision surgeries and individuals with a history of spine, infection, trauma, or tumor. The following variables were calculated: demographics, comorbidities, 90-day postoperative complications, cost, and duration of stay. Multivariate logistic regression was used to examine all of the outcomes of interest, adjusted for age, sex, and comorbidity burden. P-value 0.05 was used to determine significance. There were 2,363 MS patients and 23,569 matched control participants in the study. When compared to patients without a history of MS, investigators found a significant increase in the risk of sepsis [odds ratio (OR)=1.85, P=0.034], urinary tract infection (OR=1.89, P<0.001), deep vein thrombosis (OR=1.4, P=0.044), 90-day emergency room visit (OR=1.14, P=0.027), and 90-day readmissions (OR=1.20, P=0.011). MS patients also paid an extra $4,379 in total hospital charges, a $1,679 increase in hospitalization costs, and a longer length of stay (4.05 vs 3.61, P<0.001). An MS diagnosis was linked to a considerable increase in postoperative complications and inpatient expenditures. Physicians must be aware of the risk factors for patients with MS. The latter were undergoing PLF and posterior lumbar interbody fusion to counsel them about postoperative complications before surgery effectively.