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Failed Back Surgery Syndrome: Evaluation with Magnetic Resonance Imaging.

INTRODUCTION
Failed Back Surgery Syndrome (FBSS) is a generalized term used to describe varied spinal symptoms of patients who have had unsuccessful results after spinal surgery. The treatment of FBSS is challenging and varies from conservative management to reoperation. Imaging plays a crucial role in identifying the cause and helps to guide the appropriate therapy. Contrast enhanced Magnetic Resonance Imaging (MRI) with its superior resolution is the imaging modality of choice.


AIM
To evaluate the spectrum of imaging findings on postoperative MRI in FBSS.


MATERIALS AND METHODS
A total of 30 postoperative symptomatic patients of FBSS were included in this cross-sectional study. Of these, 26 had undergone surgery for degenerative disc disease and four had spinal fixation surgery for spondylolisthesis or trauma. Patients were subjected to detailed clinical examination. All patients underwent MRI which was done on 1.5 Tesla scanner with standard sequences in all planes. Contrast was administered in all cases. Non Contrast Computed Tomography (NCCT) scan was done in patients with metallic implants to better delineate the placement of the implant. Patients with contraindication to MRI scanning were excluded from the study.


RESULTS
Of the total 30 cases (23 males and seven females) of FBSS that were evaluated with contrast enhanced MRI of the spine, 16 patients had recurrent/residual disc herniation, six had epidural scar tissue, three patients had recurrent disc herniation and scar tissue, two had evidence of post surgery arachnoiditis, two patients had postoperative discitis and one patient had implant mal alignment. Eight patients underwent reoperation for recurrent disc herniation and one patient for implant malalignment after imaging.


CONCLUSION
MRI is the modality of choice for evaluating the postoperative spine. It helps to identify the cause and guide the appropriate treatment.