Factors Affecting the Outcome of Lumbar Canal Stenosis Surgery: A Two-year Follow-up Study

Background: Lumbar Canal Stenosis (LCS) is the most common reason for spinal surgery in older patients. Identifying factors influencing the outcome of surgical management is important in clinical research. Objectives: This study aims to identify the factors affecting the outcome of surgical management for LCS. Materials & Methods: This prospective non-randomized cohort study was conducted at the spine center of Imam Khomeini Hospital in Tehran, Iran from March 2017 to January 2019 on 135 patients with symptomatic LCS, confirmed by MRI. Clinical and functional outcomes were measured using the 12-Item Short form Health Survey (SF-12), Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) the day before surgery, and 12 and 24 months after surgery. Radiographical parameters was assessed by measuring lumbar lordosis, sacral slope, pelvic tilt and pelvic incidence.  Results: Of 135 patients, 120 completed the follow-up. Patients treated surgically had significantimprovement in SF-12, ODI and VAS scores after 2 years of follow-up. Higher values of BMI(P=0.031), symptom duration >1 year (P=0.045 for SF-12, P=0.031 for ODI), and smoking(P=0.033 for SF-12, P=0.028 for ODI) were associated with poor outcome. Patients with higher pre-operative SF-12, ODI and VAS scores (P=0.007 for SF-12, P=0.003 for ODI, P=0.050 for VAS) and lower lumbar lordosis (P=0.055) showed significant improvement after surgery. Conclusion: Patients with LCS showed significant improvement in outcomes afterdecompression surgery. Higher values of BMI, symptom duration >1 year, and smokingare associated with poor outcome, while higher pre-operative disability score and lowerlumbar lordosis are associated with better outcome after surgery.