This is a short case report article about the significance of the tender nodules in the low back (also known as back mice) published in The Journal of Orthopaedic Medicine in 2007 by G. Beverley.
The author suggests that careful palpation of any tender nodules in the low back (episacroiliac lipoma) should be included in the initial back examination. He uses a short CASE HISTORY to give his reason why it should be like that. He also emphasizes that the painful nodules can be managed by local injection of corticosteroid and anesthetic.
He warns that these tender nodules in the low back are often an OVERLOOKED cause of low back pain. And that still questions still remained related to the etiopathogenic factors.
Episacroiliac lipoma: A CASE REPORT
MERRITT, BRITISH COLUMBIA
Beverly starts his paper saying that the episacroiliac lipoma (also known as back mice) is a common finding (according to literature up to 10-16% of people).
Ries was the first one to describe them. They are tumor-like nodules that can be palpated over the sacroiliac region.
In most cases the nodules are painless, but sometimes they seem to be the cause of the low back pain. Surgical excision has resulted in pain relief.
Histology has shown that they are NOT TRUE LIPOMAS; they are described to be HERNIATION of fatty tissue through fascia.
Beverley’s case report about tender nodules in the low back
A 48-year-old woman. She was a nurse with low back pain for 14 years. She had a history of numerous visits to the doctors, chiropractor with no resolution. She described the pain as deep in the sacroiliac joint, with some radiation to the buttock and down the lateral aspect of the left leg.
She reported that she was not able to wear a belt because it would irritate the pain. No other neurological signs.
The author found certain degree of “rotation” of the sacroiliac joint. He applied some techniques without improvement.
Then, on palpation, he noticed a lipoma of about 2-3 cm over the left sacroiliac joint that was tender on palpation, he tried to “recollocate it”. To his surprise, the patient reported that it sent a wave of pain down the leg in the same distribution of the original pain. The doctor injected her 2 cc 0.25% bupivacaine hydrochloride (long lasting anesthetic). The patient had a resolution of her symptoms for 3 hours, but then the pain returned markedly increased.
The following day, they repeated the injection then with 20 mg depomedrol with 2cc bupivacaine 0.25% PEPPERING the lipoma. The patient was sore for 2 days, she managed with over-the-counter painkillers, and then the symptoms RESOLVED and the pains of 14 years disappeared.
A moderate re-occurrence presented after an episode of lifting at work 2 months later. It resolved with a new injection. Afterwards there were no further visits.
Beverley states than since then he had examined 3 other patients, presenting similar lipomas (of 1-2 cm). All had certain degree of relief with injection, but not as significantly as the woman case.
The author admits that the relationship between these tender nodules in the low back or episacroiliac lipoma and pain remains UNCLEAR.
He then mentions all the previous work from Ries (1937), Copeman and Ackerman, Herz and Hucherson & Gandy, and Singewald.
He summarizes Copeman & Ackerman‘s work that suggested that the tender nodules in the low back could be in fact fatty tissue herniated through the thoracolumbar fascia. This tissue could become sometimes OEDEMATOUS. It can also affect the peripheral cutaneous nerves that cross the fascia by certain foramina.
Beverly concludes saying that the injection appears to be a safe and effective treatment for an often-OVERLOOKED component of low back pain.
Published in July 2018 By Marta Cañis Parera
- Beverley, Graeme. “Episacroiliac Lipoma: A Case Report.” Journal of Orthopaedic Medicine 29.1 (2007): 23–24.
- David Bond. Low Back Pain and episacral lipomas. Dynamic Chiropractic– September 4, 2000, Vol. 18, Issue 19
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