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Endometriosis of the Sacroiliac Joint

Endometriosis of the Sacroiliac Joint

Dr. Supratik Sen
Pacific Point - Centre For Pain Relief
Calcutta, India

A 27 year old housewife presented with a 12 year old history of low back pain. This pain was constantly present, more on waking up. Her father is a diagnosed case of seropositive Ankylosing Spondylitis (AS). Her routine blood tests, HLA B27, MRI of Lumbosacral segment were within normal limits. Orthopedic Surgeons and Neurologists had diagnosed her as early AS. She had been on routine painkillers, Tricyclic Antidepressants and Salazopyrine. Other treatments included Acupuncture and Steroid injections in the Sacroiliac joints. But the pain relief were temporary.

The most significant part of the history was that she had 2 full term pregnancies with normal delivery. She had 2 abortions, one spontaneous at 11 weeks; another medical termination at 8 weeks. During all these periods of pregnancy, she was absolutely pain free. But in non-gravid state, this pain was unrelated to the menstrual cycle.

On examination, she had bilateral Sacroiliac Joint (SA) pain (Sacroilitis). Right joint was less painful than the left, as she had been administered Triamcinolone in it.

On explaining to the patient that an environment of pseudo-pregnancy may help her, she agreed. She was put on Medroxyprogesterone Acetate; 10mg. tid. After a month, her pain started subsiding. Now it is 2 months since the drug was started. She has negligible pain and has been off painkillers for the first time in 12 years.

Although Endometriosis in the SA joint is not known, the peculiar history and the dramatic response leaves a big question for further discussion.

Dr. Supratik Sen
Consultant in Pain Management
Pacific Point - Centre For Pain Relief
57/14 Ballygunj Circular Road
Calcutta - 700019 India


I would love to hear more of endo being found on certain nerves. As I read of the patient with the lower back pain, it seemed as though I was reading about myself almost. I have  had lower back pain for approx. 10 years (I am now 28), 3 full-term pregnancies, 1 miscarriage. I have been diagnosed with endometriosis, IBS, and fibromyalgia,  I am on effexor and zoloft but no relief for lower back pain which is worse in waking. I also have shooting pains down my right leg at times and extreme pain in my right hip almost constantly. Is there any relationship between the pain and endometriosis?  I would love to find out!

Vicky L Evans

Endometriosis can cause back pain when it is involving the uterosacral ligaments, in which case it can radiate pain to the lower sacral region. The uterus also can radiate menstrual or non-menstrual pain to the same area, as well as down the front of the thighs or up to the umbilicus.  Palpation of the uterosacral ligaments or uterus during exam may be able to reproduce back ache if it is coming from one of these areas. Involvement of named nerves by endo is very rare and is more common on the right side by a 9:1 ratio.  Endo
of the obturator nerve would affect the inner thigh, whereas endo near the sciatic nerve could affect the rear of the leg and perhaps the hip. Nerve conduction studies may be abnormal, and obviously orthopedic or other neurologic situations should be excluded.  Endo pain usually worsens before or during menses, and she didn't mention that, so her pain may not be due to endo. The only way to know is to do surgery and look for endo and remove it.  Endometriosis of the sciatic nerve is associated with a "pocket" sign on the sidewall with endometriosis at the bottom of the pocket.

David Redwine, MD