The aetiologies of Failed Back Surgery Syndrome: A systematic review.

PURPOSE: Four to fifty percent of patients will develop Failed Back Surgery Syndrome (FBSS) following lumbar spine surgery. Repeated surgeries lead to escalating costs and subsequent decreases in success rate. Much of the research to date has focused on the psychosocial factors associated with FBSS. All factors including physical and pathological aetiologies should be examined. These factors may be independent, co-exist with or predispose patients to the psychological factors associated with FBSS. Previous reviews on the topic have been limited by a lack of systematic overview. The aim of this review is to identify the physical, physiological and pathological aetiologies of FBSS.

METHODS: This review was done in accordance with the PRISMA guidelines. A computer-aided search of the electronic databases from inception to December 2014 was performed. Outcome measures of interest included pain, functional and radiological assessments. Two reviewers independently selected studies for inclusion. Methodological quality was assessed using the Newcastle Ottawa Scale.

RESULTS: Six studies met the inclusion criteria and included a total of 663 patients. A total of twenty two aetiologies were identified. Only three studies reviewed non-surgical aetiologies. Many of the studies relied on medical imaging to identify the aetiologies. A meta-analysis was not undertaken due to the heterogeneity of studies.

CONCLUSIONS: The causes of FBSS can be attributed to patho-anatomical, peripheral pain generators, physical/ mechanical, neurophysiological, surgical and `other' aetiologies. Three of the studies only examined surgical causes of FBSS. Further research, that examines surgical and non-surgical aetiologies, is required to draw firm conclusions. With nineteen aetiologies identified, FBSS remains an unclear diagnosis for a complex heterogeneous group of patients.