en Spine Research <div style="text-align: justify;"><strong>Background and Aim:</strong> The incidence of obesity has steadily risen to epidemic proportions in numerous world regions. Surgeons often encounter problems in surgeries on obese patients. This study evaluated the effects of Body Mass Index (BMI) on the outcome of patients undergoing lumbar microdiscectomy.<br> <strong>Methods and Materials/Patients: </strong>This was primarily a case-series retrospective study of patients who underwent single-level lumbar microdiscectomy at our institution between January 2014 and April 2018. BMI was used to categorize our patients. Outcome measures were Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS). The Patients were also analyzed according to the operative time, average blood loss during surgery, hematoma formation, wound infection, Cerebrospinal Fluid (CSF) leak, deep vein thrombosis, length of stay after surgery, recurrent disc herniation, and neurologic deficit. Analysis of Variance (ANOVA) and regression analysis methods was used to assess differences between the study variables.</div> <div style="text-align: justify;"><strong>Results:</strong> Five hundred patients (225 male & 275 female) with a Mean&plusmn;SD age of 40.3&plusmn;5.2 years (range: 19-70 y) who underwent single-level lumbar microdiscectomy were enrolled for the study. All patients were followed up for 24 months after surgery. The VAS and ODI were<br> significantly improved in all patients. There was no significant difference between groups concerning the operative time, average blood loss during surgery, hematoma formation, wound infection, CSF leak, deep vein thrombosis, length of stay after surgery, recurrent disc<br> herniation, and neurologic deficit.</div> <div style="text-align: justify;"><strong>Conclusion: </strong>The obtained findings indicated that BMI did not negatively impact the outcome of patients undergoing lumbar microdiscectomy.</div> Body Mass Index, microdiscectomy, lumbar, outcome 197 204 http://irjns.org/browse.php?a_code=A-10-281-2&slc_lang=en&sid=1 Amir Abbas Ghasemi dr.amirghasemi@ymail.com 10031947532846007377 10031947532846007377 Yes Department of Neurosurgery, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran