Back Mice

Episacroiliac Lipoma, otherwise known as Back Mice, are a cause of low back pain caused by fatty tissue that has herniated through the fascial layers in the low back. The term Back Mouse was coined by Peter Curtis in his 1993 paper: In search of the ‘back mouse,’ due to its mobility and change of size over time.i I first encountered the back mouse while performing chair massage in massage school. I had no knowledge of the condition and I was curious as to what they could be. The few clients I observed them in were middle-aged women with complaints of low back discomfort though the palpation of the nodules did not invoke a pain response.  

The basic characteristics of a Back Mouse are firm, rubbery, mobile nodules located in the sacroiliac, posterior superior iliac, and, lumbar paraspinal regions. Observing these characteristics upon palpation combined with either relief of pain with local anesthetics or positive identification upon ultrasound are key in diagnosis.ii The back mice are easiest to palpate when the patient/client is slightly bent over at the waist at a 75-degree angle.iii When the back mouse nodule is causing peripheral nerve neuropathy and/or entrapment, differentiating back mice versus spinal stenosis/herniation or neuropathy can be accomplished by negative straight leg raises, lack of sensory findings, and intact reflexes. 

Western Medicine treatment considerations include local anesthetic injection, corticoid steroid injection with repeated needling, surgical resection of the herniated tissue, and liposuction. Treatment is not usually required unless the back mouse is causing unmanageable pain.iv   

Massage Therapy can help manage the pain and discomfort caused by the back mouse. Paraspinal massage, hip massage, and thoracodorsal fascial stretching can be a good treatment for reducing pain/discomfort and providing relief from the back mouse. When massaging a client with back mice it is important to avoid direct pressure over the nodule as well as avoid stretching and bending that weakens the low back.v 

In Traditional Chinese Medicine, Back Mice are considered to be caused by damp/phlegm stemming from water accumulation in the low back due to low kidney yang.vi This can be treated by clearing damp from the Large Intestine with digestive cupping and citrus essential oils, and tonifying the Kidneys by using moxibustion on the Kidney Shu points.

Notes:

i The Best-Laid Plans of “Back Mice” and Men: A Case Report and Literature Review of Episacroiliac Lipoma, retrieved from: https://www.painphysicianjournal.com/current/pdf?article=MjYxMg%3D%3D&journal=95

ii Trapping “Back Mice”: A novel approach to the evaluation and treatment of painful subfascial fat herniations, retrieved from: https://www.researchgate.net/publication/332159014_Trapping_Back_Mice_A_novel_approach_to_the_evaluation_and_treatment_of_painful_Subfascial

_fat_herniations 

iii backmice.info

iv Are Back Mice Real?, retrieved from: https://www.verywellhealth.com/back-mice-or-episacroiliac-lipoma-296970

v The Problem with the Back Mouse, retrieved from: https://www.massagetherapy.com/articles/problem-back-mouse 

vi Back Mice! A Weird Cause of Back Pain, retrieved from: acupunctureinthepark.com/pain/back-mice-a-weird-cause-of-back-pain/