Episacral Lipomata as a Cause of Lower Back Pain: Series of Cases Managed by Excision

Abstract

IntroductionEpisacral Lipomata or the “back mouse” is a tender, fibro-fatty subcutaneous nodule found in the thoracolumbar fascia area in up to 16% of people. The “back mouse” can be a cause of significant low back pain in patients with associated disc disease, nerve root compression and facet hypertrophy. This is due to the particularly dense innervation with substance P positive free nerve endings in the posterior layers of the fascia. Material and MethodsWe studied the outcome of removal of the ‘back mouse’ in nine patients with twelve lipoma's (three had bilateral lipoma's). The diagnosis was made by clinical examination and all of the excised nodules were confirmed to be episacral lipoma on histo pathological examination subsequently. The outcome was measured with Visual Analog Scale (VAS) scores and Oswestry Disability Index (ODI) scoring. The average VAS reduced from 7.8 pre operatively to 4.8 post operatively. ResultsSix patients had improvement in ODI from moderate to minimal disability, one patient had improvement from severe to moderate disability and the ODI in three patients were unchanged. Seventy percent of the patients were happy with the outcome as the symptoms had significantly reduced despite having some other underlying spinal pathology. ConclusionIn our opinion, episacral lipoma may be an unrecognized entity by both specialists and generalists and can be a treatable cause of low back pain. The excision provided relief to the compressive effect it had on the middle and posteriro layers of the lumbar fascia and the muscles it encloses. Marginal excision of a painful episacral lipoma may provide pain relief and improved lower back function in patients who are carefully selected for this procedure,