Frederick R. Jelovsek MD
Many women do not realize that pelvic pain can actually be due to muscle problems in the abdominal wall or even back problems of the spinal discs or bones that are referred or perceived as being in the pelvic area. This type of pain is broadly categorized as myofascial pain. Some doctors fail to thoroughly evaluate this possibility as a cause of chronic pelvic pain.
A recent article, Myers CA: Musculoskeletal factors of chronic pelvic pain. OBG Management 1999; Feb:10-12, gave us some information to answer questions about this uncommon cause of pelvic pain.
How can pain actually be “referred” from another site to the pelvis?
The spinal cord is a complex electrical connection system. The nerve roots of the spinal cord send off neurons that sense pain from skin, muscles, bones, ligaments and internal pelvic organs. The same spinal nerve roots that innervate the ovaries may also innervate abdominal wall muscles. Low back pain can arise from pain in the uterus, bladder, faloppian tubes, and cervix because the same nerves innervate those organs as well as the lumbar discs, ligaments and muscles. Conversely, abdominal wall pain, especially around an incision, may actually feel as if it is arising from the uterus or deeper in the pelvis when its origin is from the skin near an incision. Neurologists think that sometimes the spinal cord just gets confused when there are many pain impulses coming in and by the time your brain perceives the pain, it cannot tell whether the source is in the internal organs or the external muscles.
There are also internal muscles lining the pelvic bone such as the piriformis, puboccocygeus, obturator internus and externus muscles. The muscles can present with cramps and achiness and a woman perceives the pain as uterine or ovarian.
How is musculoskeletal pain differentiated from pain arising in the pelvic organs?
Certain questions help to categorize the pain as more likely to be musculoskeletal in origin rather than urogenital organ in origin if:
- you have a history of musculoskeletal injury to the back, hips or knees.
- your occupation is sedentary or labor intensive.
- you have repetitive musculoskeletal or postural stressors.
- physical activity worsens or lessens the pain.
- positional changes (lying to sitting, sitting to standing) worsen or relieve the pain.
- the pain changes with the time of day.
- there is noticeable muscle weakness or numbness or tingling.
- there is a history of inflammatory or collagen vascular disease such as rheumatoid arthritis or lupus.
On physical exam, what findings suggest musculoskeletal dysfunction?
If there is any abnormal curve in the spinal canal such as a curvature to the right or the left (scoliosis), excessive curve of the thoracic spine like a hunch-back (kyphosis) or increased arching of the small of the back (lordosis), these changes make it more likely for the pain to be musculoskeletal. The doctor will also have you lie flat on an exam table, raise your knee and will rotate the knee from side to side to see if any of the internal and external hip rotators are tight and cause pain with rotation. Next you will be asked to bring the one knee up to the chest. If the straight leg whose knee is not being raised comes up off the table or gives pain, this means the iliopsoas muscle and/or the rectus femoris (hip flexor) muscles are tight and may actually be the source of deep pelvic pain mistaken for internal organ pain. The doctor will also check for any pain in the abdominal muscles and touch the skin of the abdomen and back to see if there are places on the skin that “trigger the pain”.On pelvic exam the doctor will have you try to tighten the muscles around two fingers placed in the vagina and will palpate the muscles of the interior pelvic wall to see if any of them are exquisitely tender. All of these screening exams can be checked for by you at home to see if they are abnormal.
If pelvic pain is actually coming from the back and spine, how is it treated?
Certain postural problems, especially kyphosis and lordosis, have been clinically correlated with pelvic pain as have other muscle weaknesses and spasms. Treatment of those problems has also been shown to help the pelvic pain. If there is any suspicion that pelvic pain has a myofascial cause, a woman should be referred to a physical therapist for a more in-depth evaluation and plan for treatment. You can find medical centers specializing in comprehensive pain management that can aid in treatment. Physical therapy and muscle exercises can also significantly help these problems.
What are trigger point injections and are they helpful?
Trigger points are areas of skin on the abdominal wall that follow along one dermatome, the area of skin innervated by one specific nerve root. When touching them lightly even with a Q- tip, pain is elicited that feels as if it arises deep in the pelvic organs. When these areas are injected with a local anesthetic, there is pain relief that lasts longer than the expected duration of the specific anesthetic used. After about 5- 6 weekly injections or less, the pain totally goes away. This is thought to work somewhat like acupuncture in that the pain sensation the level of the spinal cord gets rearranged to know that the pain does not actually arise in the pelvic organ where it is perceived.