1952 Herz – painful nodule low back pain

This is Herz’s second article about subfascial fat herniation as a painful nodule that can be a cause of low back pain (also named back mice). The first article, titled Herniation of Subfascial Fat as a Cause of Low Back Pain (37 cases), was published in 1946 (6 years before).

He describes “subfascial fat herniation as a clinical entity in which fat herniates from a deep stratum to a more superficial one”.

It has just 2 references to other authors’ work, to Copeman (Textbook of Rheumatic Diseases) and Copeman & Ackerman (1944).

He presents a study of 302 cases of low back pain, many of whom were undiagnosed low back pain and were related to the presence of painful nodules in the lower back. He explains the surgical technique, the anesthetic injection diagnostic test and the differential diagnosis that has to be done.

In the summary of his article, Ralph Herz mentions that the proportion of cases of subfascial fat hernias in that series (89/302 removed by operation, and 92/302 managed by injection) had a high incidence, SINCE MANY PATIENTS WERE REFERRED TO HIM from other physicians on account of his known interest in this condition.

Nevertheless, the author warns that many cases of undifferentiated low back pain may belong to this entity.

It does not include the selection criteria of the patients and the outcomes, except for the 5 case reports that present excellent outcomes after surgical removal.

HE DOES NOT talk about the etiopathogenic factors related to the nodules and insists that they are mainly due to a PAST TRAUMA. In one microscopic examination there is a mild inflammatory reaction that is related to the trauma.

Personal notes on the article:

Subfascial Fat Herniation as a Cause of Low Back Pain: Differential Diagnosis and Incidence in 302 Cases of Backache

Ralph Herz

Key West, Florida, USA

Ann Rheum Dis 1952 11:30-35

Doi: 10.1136/ard.11.1.30

Free on line article.

Herz’s introduction about subfascial fat herniation as a cause of low back pain

 He describes “subfascial fat herniation as a clinical entity in which fat herniates from a deep stratum to a more superficial one”.

It usually occurs in the lumbo-sacral or sacro-iliac area, usually as a result of a trauma.

The chief characteristic is the presence of single or multiple painful nodules, which the patient is frequently able to localize.

The pain can be severe and the patient is unable to move (symptoms can be similar to strangulated inguinal hernia).

These nodules have been called “fibrositis” since originally they were thought to be caused by excessive fibrous tissue.

He presents a report of 302 consecutive cases of previously undiagnosed low back pain.

Historic overview about fat herniation as a cause of low back pain

Herz mentions that Copeman and Ackerman, in 1944, were the first to show that the painful nodules in the low back were actually herniation of fat through the superficial fascia. Herz himself also confirmed and increased these results in 1946.

The injection of 5 ml of 1% procaine underneath the nodules will produce startling and dramatic results, with the patient relieved of the pain within a few minutes; it is usually a temporary effect, but it can be used as a diagnostic technique and as a treatment if repeated.

Surgery is reserved to those cases where relief from injection is too short or it is impracticable.

Nevertheless, Herz warns that surgical removal should never be attempted until the local anesthetic test is performed since, if the injections fail, there is little likelihood that an operation for subfascial fat hernia would give relief.

Copeman & Ackerman correlated the distribution of subfascial fat with the localization of the trigger-points. Herz refers to the original graphic from Copeman and Ackerman (1944).

painful nodules

Of course, a detailed examination should be done to do a proper differential diagnosis. X-Rays have to be performed. The sacro-iliac joints should be clearly delineated, since involvement of these joints was often thought to be the cause of low back pain when actually the fat herniation was the causative agent.

We mustn’t forget that more than one cause can coexist. For example, painful nodules are frequently present when there is also evidence of arthritis of the spine. Treatment of just the arthritis would not relieve the patient, but the symptoms can be greatly relieved if injections of anesthetic are ALSO GIVEN.

Other pathologies, such as retrocaecal appendicitis, or nephrolithiasis, have to be discarded, as well as many other traumatic causes, and post-traumatic cyst pressing on the sciatic nerve (Herz published an article about it in 1948).

RESULTS FROM 302 cases with low back pain

  • Subfascial fat hernia relieved by operation: 89
  • Painful nodules relieved by anesthetic injection: 92
  • Painful nodules with chronic arthritis of spine: 39
  • Incomplete cases (relief followed on injection of anesthetic of painful points, but no follow-up): 50
  • Undiagnosed (injection gave NO relief and no other cause for backache was revealed): 8
  • Disrupted intervertebral disc (two also had subfascial fat hernias): 6
  • Post-traumatic cyst pressing on sciatic nerve: 3
  • Tuberculosis of spine: 1
  • Fractured coccyx: 2
  • Incomplete fracture lumbar spine: 1
  • Spondylolisthesis (roentgenographic diagnosis): 3
  • Sacro-iliac dislocation (roentgenographic diagnosis): 3
  • Renal calculus: 2

Removal surgical technique for fat hernia

painful nodule

 The area is blocked with 30-50 ml of 1% novocaine.

The skin is incised; the fat hernia is excised by sharp dissection.

The size of excised fat is showed in figure 4.

The microscopic sections of excised fat show mild inflammatory process (probably TRAUMATIC).

If the hernia opening cannot be located, the dissection is continued until deep fascia is encountered.

painful nodule


Haemostasis is attended and the wound sutured, preferably with stainless steel wire. A rubber drain is inserted for one week to prevent accumulation of fluid and facilitate healing. Dressings should be changed daily. Sutures removed within 8 to 12 days. Wounds in the back do not heal as rapidly as those on the anterior part of the body.

Case reports of subfascial fat herniation or painful nodules as a cause of low back pain

 Case 1. A 24-year-old female. She had RECURRENT ATTACKS OF LUMBAGO for 17 years. Roentgenograms showed advanced oseto-arthritis. She had, in addition, subfascial fat hernias, which were treated surgically. For the last 5 years NO attacks of lumbago and the arthritis went any further.

Case 2. A 43-year-old female. Previous fall 2 years before consulting. Roentgenographic examination disclosed a fracture of the coccyx and an injury to the sacrum. In addition, she had a fat hernia that was removed at the time of the operation of the coccyx with satisfactory relief.

Case 3. A 46-year-old female. She had past history of 2 falls with severe back pain. There was discomfort while sitting and referred pain to the leg. Since all the therapeutic measures failed (including treatment for arthritis), her physician concluded the pain was psychogenic.

Herz found a trigger point in the left sacro-iliac region and a large palpable mass in the left buttock. Relief was obtained with an injection of 1.5% of METYCAINE.

Then they performed surgical removal over the left sacro-iliac region and removed a large mass of dense fibrous tissue. Microscopic examination showed an organized haematoma with multiple hemorrhagic cysts, which were pressing on the sciatic nerve. The patient got relieved from the symptoms.

Case 4. A 37-year-old male. Not known trauma. Pain from the right heel to the thigh. A subcutaneous mass was located near the right sacro-iliac joint. The diagnostic injection test with anesthetic gave prompt relief of short duration. The surgical removal gave permanent relief.

Case 5. A 23-year-old female. She was involved in a motor accident in 1948 with trauma of the back. She had undergone different treatments (including Paris Jacket) without good results. She got relief with injection of several painful nodules. The relief was permanent after surgical removal.

Published in September 2018 by  Marta Cañis Parera     ORCID iD icon