Leg weakness (OR 2.826), WBC (OR 1.101), CRP (OR 1.072), identification of causative bacteria (OR 2.187), bacteremia (OR 4.455), additional surgical treatment (OR 5.333), recurrence (OR 8.600), extent of lesion (OR 1.590), epidural abscess (OR 4.792), and back muscle abscess (OR 2.436) in univariable analysis; and procedure-related (OR 2.702), CRP (OR 1.062), bacteremia (OR 4.966), additional surgical treatment (OR 6.524), recurrence (OR 12.453), and paraspinal abscess (OR 5.965) in multivariable analysis; were statistically significant factors for the above-average length of hospitalization. This evidence concerns the gene CRP and epidural abscess.