Relationships between epidural fibrosis, pain, disability, and psychological factors after lumbar disc surgery

Failed back surgery syndrome (FBSS) is an important complication of lumbar disc surgery. Epidural fibrosis is one of the major causes of FBSS. However, most patients with epidural fibrosis do not develop symptomatic complaints from scarring. The purpose of this prospective study was to evaluate the relationships among the severity of epidural fibrosis, psychological factors, back pain and disability after lumbar disc surgery. Twenty-nine surgically managed patients (13 women, 16 men) were included in this study. In all patients, the presence and severity of epidural fibrosis was determined with contrast-enhanced magnetic resonance imaging (MRI). A pain visual analog scale (VAS) and Oswestry Disability Questionnaire (ODQ) were completed before and after surgery. Subjects were grouped by their type of herniation (protrusion, free fragment), MRI findings and results of the mini form of the Minnesota Multiphasic Personality Inventory (MMPI), and the groups were compared fur their VAS and ODQ scores. Our results disclosed that neither the postoperative VAS scores nor the postoperative ODQ scores differed significantly among the epidural fibrosis severity groups. Moreover, postoperative VAS scores were positively correlated with the scores of the mini MMPI. These findings indicate that epidural fibrosis may be considered as a radiological entity independent of patients' complaints. Furthermore, the mini MMPI should be included in the assessment and planning of the reoperations in FBSS patients, because of the importance of psychological factors in postoperative pain and disability.