Factors Associated With Failure of Spinal Anesthetic: An 8-Year Retrospective Analysis of Patients Undergoing Elective Hip and Knee Joint Arthroplasty

The primary outcome of this 8-year retrospective review was the failure of spinal anesthetic (SA) in elective hip and knee joint arthroplasty surgery. Of 3542 SAs, a total of 135 failures were identified (3.8%). Factors associated with increased odds of failure were younger age (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.01-1.05), lower body mass index (BMI; OR, 1.04 [1.01-1.08]), hip arthroplasty (OR, 1.90 [1.28-2.84]) compared to knee arthroplasty, needle insertion at L4-5 (OR, 4.61 [2.02-10.54]) and L5-S1 (OR, 7.66 [2.47-23.7]) compared to L2-3, 22-gauge needle size (OR, 2.17 [1.34-3.52]) compared to 25-gauge needle, and hyperbaric bupivacaine (OR, 1.66 [1.09-2.53]) compared to isobaric bupivacaine.