1995 Earl et al. (Back mice -A prevalence study)…studying low back pain

Notes on the article:

“Back Mice” – A prevalence study


Earl DT, Lynn JC, Carlson JM.

J Tenn Med Assoc. 1995 Nov;88(11):428-9. PubMed PMID: 7475021.

From the Department of Family Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City.

 Earl et al. introduction

They start with the sentence that “back pain is one of the most common ailments encountered in primary care”, with high expenses.

Hyperlordosis, poor posture and faulty lifting techniques have been related as risk factors to develop low back pain.

Notes related to “back mice”

Ries first described “back mice” as palpable soft-tissue fibrotic lesions in the back.

-They have been described as being single or multiply and located in lumbar zone.

-There is controversy about the clinical significance of these lesions and how they should be treated (by lidocaine injection, excisional biopsy or physical manipulation).

-Curtis et al. proposed that the incidence would be 16% in general population and that they are associated with past history of back pain.

-Earl et al. had the impression that prevalence would be higher than previous studies reported, higher than 16%. That’s why they examined a group of patients for the presence of back mice and history of back problems.

Study methodology

-It is a PROSPECTIVE study from Family Medicine outpatient clinic with 18 family physicians in Johnson City.

-100 people (over 17 years) were asked to participate in the study-

-There was informed consent.

-Brief questionnaire (McGill Pain Questionnare) was related to history of back problems.

-Patients were palpated with standarized examination.

-They did SPSS statistical analysis.

Results from the 100 people study

-68 women and 32 men

-Average 17-78 years


-The only statistical difference was found in the use of NSAIDs with an inverse relation.

DISCUSSION from Earl et al. paper

-They found a higher prevalance than previous reported.

Back mice were unrelated to any of the variables examined.

-The presence of back mice is apparently a benign, asymptomatic finding.

-Some people that reported NO history of back pain had a palpable back mouse.

They propose a change in nomenclature: The ones that are benign asymptomatic fibrotic masses are to be called BACK MICE and those which are TENDER or painful “back rats”!

Back mice vs back ratsratsratsrats

Published in June 2018 by Marta Cañis Parera   ORCID iD icon


  • Earl DT, Lynn JC, Carlson JM. “Back mice”–a prevalence study. J Tenn Med Assoc. 1995 Nov;88(11):428-9. PubMed PMID: 7475021.
  • Curtis Peter. In search of the ‘back mouse’. J Fam Pract. 1993 Jun;36(6):657-9. PubMed PMID: 8505609.
  • Reis E. Episacroiliac lipoma. Am J Obstet Gynecol 1937;34:492-8.