David bond published 2 articles about episacral lipoma or back mice. One, in 2000 and another one, in 2004. This is the first published work.
He does an EXTENSIVE BIBLIOGRAPHICAL REVIEW about the entity known as episacral lipoma or other names (actually, his article gave us the clue to find more medical publications when we started to be intrigued with the “back mice story”). He mentions Ries (1937), Copeman (1944-1947), Herz (1945), Hucherson (1948), Dittrich (1951-1956), Bonner (1954), Wollgast (1961), Singewald (1966), Pace (1972), and Faille (1978).
He presents a male case that had just temporary relief of his low back pain (2-3 hours) after injection into the tender episacral lipoma area.
By the date of publication NO research in the chiropractic profession had been done. And Bond warns that episacral lipoma should be considered more often in the differential diagnosis of acute or chronic low back pain.
After his research, Bond questions himself about the episacral lipoma: Are the patients with episacral lipoma the ones who complain of intractable low back pain?
Low back pain and episacral lipomas
By David Bond
David Bond starts this article warning that episacral lipoma is an OFTEN OVERLOOKED cause of low back pain. Although it may be considered as a minor condition, it is capable of producing considerable low back pain.
Bond describes the episacral lipoma BASED ON A BIBLIOGRAPHIC REVIEW as: small, tender, “tumor-like” nodules occurring mainly over the sacroiliac region that can cause disabling low back pain.
Actually, the term “lipoma” of the episacral lipoma is used to describe how the nodules can be felt through direct palpation over the region. The examiner is able to detect a subcutaneous mass similar to the benign tumors -the true lipomas-. However , in fact, the episacral lipoma is NOT a real tumor. It is described to be subfascial fat that has herniated through the overlying fascial layer.
Bond mentions the work of Ries (1937), who was one of the first authors that published about these nodules.
But Copeman & Ackerman are the authors that described that the fatty masses could be actually subfascial fat herniation. They performed surgical remove of the masses with striking relief of the pain symptoms.
Herz also published the case of 6 women with excruciating low back pain sometimes accompanied by unilateral leg pain. It was related to previous trauma. The women got relief after removal of herniated fat tumor.
Copeman & Ackerman published further studies and they observed edematous fat lobules herniating through deficiencies of the fibrous compartments. They noticed that in certain spots the fat tended to BULGE THROUGH. They also described 3 types of fat herniation: pedunculated, non pedunculated (it has a fibrous pedicle), and foraminal (the posterior cutaneous nerve branches pierce the fascia through the foramina). They also described a horizontal membrane fold that would have the fascial foraminal that normally should prevent the fat from herniating. Biopsy just showed normal fatty tissue with certain edema. No other consistent findings.
In 1948 Hucherson & Gandy reported that 32 patients who had undergone surgical removal of the lipoma experienced pain relief (2 patients failed).
Many other authors reported the immediate relief obtained by injection of local anesthetic. At times, there was no recurrence of the pain.
Anatomical references of the episacral lipoma
The fat herniation originates in a focal region, along the sacrospinalis edge just above the iliac crest, close to the natural dimple in the sacroiliac area. In this area, through ABNORMAL TENSION, TRAUMA, INHERENT WEAKNESSES OF THE FASCIA OR THROUGH FORAMINA FOR CUTANEOUS NERVES the underlying fat pad may herniate through the fibrous tissue between the superficial and deep layers.
Pain mechanism of episacral lipoma
The mechanism of pain is not fully understood. It seems due to the expansion of the fatty tissue within the fibrous capsule, so the removal of the lipoma alleviates the pain.
The pain can be local or it can radiate.
Upon palpation the patient is usually able to localize the EXACT POINT of extreme, or pinpoint, tenderness -it is different from a trigger point as described by Travell, where the examiner can palpate a definite mass rather than a TAUT BAND of skeletal muscle. HOWEVER, firm pressure may produce pain that radiates in a segmental distribution.
There can be a paraspinal muscle spasm.
The pain can radiate usually to the same side of the affected lipoma, there is no uniformity of the radiation area.
The pain can be significantly alleviated by the injection of local anesthetic, at least temporarily.
Bond says that in some cases it had been described that the patients may not respond to the traditional treatments of physiotherapy (heat, pain, massage, and manipulation). And he warns that there seem not to be published works from a CHIROPRACTIC standpoint.
Some patients stated that bed resting could increase the pain.
CURRENT CASE STUDY with episacral lipomas
A 39-year-old male was referred to Bond’s Clinic for evaluation of a work-related injury to his low back. He presented low back pain radiating to the left lower extremity. He had a MRI done that show multilevel disc bulges with obscuration of the L5-S1 nerve root. An EMG showed chronic denervation of left L5-S1 nerve root.
The patient was referred to an orthopedic surgeon and underwent LUMBAR LAMINECTOMY and DIRECTORY. Following surgery, he improved but still presented 30% of low back pain. He pointed that the greatest area of pain was his left episacral region with radiation to the hip.
PALPATION revealed a HARD NODULE of approximately 2 cm in diameter directly overlying the PSIS. Firm pressure reproduced the complaints of low back pain. A second nodule was palpated on the opposite side (asymptomatic). They injected a mixture of dexamethasone and zylocaine. Upon injection, he experienced immediate relief lasting for 2-3 hours. He was able to bind forward at the waist without difficulty. Subsequent injections alleviated pain for 2-3 hours, but not with a permanent relief.
According to medical studies, the treatment of choice is injection, and in recurrent cases surgical removal of the episacral lipoma (with fascial wound repairing in certain cases).
Published in July 2018 By Marta Cañis Parera 
References
- David Bond. Low Back Pain and episacral lipomas Dynamic Chiropractic– September 4, 2000, Vol. 18, Issue 19
- Ries 1937, Copeman 1944-1947, Herz 1945, Hucherson 1948, Dittrich 1951-1956, Bonner 1954, Wollgast 1961, Singewald 1966, Pace 1972, Faille 1978