Are Back Mice Real?

Back mice is a colloquial term used to describe painful bumps in and around the hips, sacrum, and low back. It is not a medical term but one that people apply to many different conditions in which a fatty lump develops in or around the back and spine.

The term is used more by chiropractors than medical professionals. Some argue that the non-specificity of the description may lead to misdiagnoses and incorrect treatment if the underlying causes are not properly investigated.

Back mice were first described in medical literature 1937 when a physician named Emil Reis used the term in association with a condition called episacroiliac lipoma. Since then, a number of other conditions have been associated with back mice, including Iliac crest pain syndrome, multifidus triangle syndrome, lumbar fascial fat herniation, and lumbosacral fat herniation.

The fat masses tend to have a firm, rubbery quality to them. You might also find them on the hip bones as well as the sacroiliac region.

Besides being unsightly, back mice can often cause excruciating pain, most often related to the underlying fascial damage and/or the pressure placed on nerve endings. They are typically tender to touch and can make sitting in a chair or lying on your back difficult. Back mice are movable beneath the skin and often found by chiropractors and massage therapist during a routine treatment.

Because of their nonspecificity, back mice are often diagnosed presumptively by injecting a local anesthetic into the lump. The belief is that, if the pain is relieved, then the lump is likely a back mouse. This is a problematic means of making a diagnosis since giving a local anesthetic, by its nature, will relieve nerve sensations and therefore pain.

The fatty deposits can be any number of things, some serious and others not. The same applies to the nerve pain. While a lipoma is the most obvious explanation, others include:

• Sebaceous cysts, a benign, fluid-filled capsule within the skin between the dermal and epidermal layers of skin
• Subcutaneous abscess, the consolidation of pus beneath the skin which is often painful but not always red or inflamed in the early stages
• Sciatica, radiating nerve pain that runs down one or both legs caused by a herniated disc or a bone spur in the lower back
• Liposarcoma, malignant tumors that sometimes appear as fatty intramuscular growths

Painful lipomas are also associated with fibromyalgia, a condition that requires the care of a qualified rheumatologist.

Unless there is an unmanageable pain, a back mouse will not usually require treatment. This presumes, of course, that the growth is benign and has been properly diagnosed as such.

If surgery is indicated, it would consist of excision of the mice followed by repair of the fascia. This procedure appears to be the only way to achieve durable pain relief.

The problem is that some people have hundreds of back mice, making complete removal less likely. If the back mice are smaller, more extensive, and more fluid, liposuction may also be explored.

Complementary and Alternative Treatment (CAM)

Many chiropractors believe that back mice can be successfully treated by combining acupuncture and spinal manipulation. It is certainly a less invasive method of treatment and one that is unlikely to do any harm.

A 2016 case study published in Pain Physician reported that the injection of a local anesthetic or steroids into the nodules, followed by dry needling (an alternative therapy similar to acupuncture), improved pain relief. The conclusions of the study are limited by the fact that only one subject was studied.