Few useful interventions exist for patients with persistent low back pain. We suggest that a fibro-fatty nodule ("back mouse") may be an identifiable and treatable cause of this and other types of pain.
We describe 2 patients with painful nodules in the lower back and lateral iliac crest areas. In both cases, the signs and symptoms were unusual and presented at locations distant from the nodule. One patient complained of severe acute lower abdominal pain, and the other had been treated for chronic recurrent trochanteric bursitis for several years.
In both patients, symptoms appeared to be relieved by multiple injection of the nodule.
There is agreement that back mice exist. Referred pain from the nodules might explain the distant symptoms and signs in these cases. Multiple puncture may be an effective treatment because it lessens the tension of a fibro-fatty nodule.
Randomized trials on this subject are needed. In the meantime, physicians should keep back mice in mind when presented with atypical and unaccountable symptoms in the lower abdomen, inguinal region, or legs.
Department of Family Medicine, School of Medicine, University of North Carolina, Chapel Hill 27514, USA. firstname.lastname@example.org