Pain Sensitization and What Should Be Done About it?

Rehabilitation interventions targeting pain in women with endometriosis should be developed.

Key Points

Highlights:

• Women with more advanced-stage endometriosis experience pain sensitization and lumbopelvic impairments.

Importance:

• This finding underscores the importance of developing rehabilitation interventions that target pain and lumbopelvic problems in women with endometriosis.

What's done here:

• Researchers conducted a cross-sectional study in 41 women with endometriosis and 25 healthy volunteers that assessed pain and related catastrophizing thoughts.
• A numeric rating scale, pressure pain thresholds, the slump test, and the pain catastrophizing scale were used to assess pain and catastrophizing thoughts.
• The women’s lumbopelvic muscles were also evaluated using ultrasound imaging, flexor/extensor resistance tests, and the lumbopelvic stability test.

Key results:

• Women with endometriosis had increased pelvic pain and reduced pressure pain thresholds in the affected areas.
• The prevalence of lumbar nerve root injury or irritation pain and catastrophizing thoughts were higher in women with endometriosis.
• Women with endometriosis also had decreased transversus abdominis muscle thickness, reduced resistance of flexor and extensor trunk muscles, and lower lumbopelvic stability. 
• Women with advanced-stage endometriosis had worse results in these parameters.

Limitations:

• Due to the cross-sectional nature of this study, it is not possible to reach a causal conclusion.
• The sample size is small, so it may not be possible to identify some differences between groups. 
• Some women in the control group may have endometriosis lesions that are not visible with ultrasound.
• It is not possible to generalize the findings as women with other chronic overlapping pain conditions were excluded from the study.
• The study did not explore any possible link between abdominal and lower back pain and lumbopelvic impairments. 
• Differences in the treatment of each patient may influence the results of the study.
• The study evaluated lumbopelvic stability in an independent manner.

Lay Summary

Pain sensitization and lumbopelvic impairments are common among women with endometriosis, especially if they have advanced stage disease. This is according to a study by researchers in Spain that was published in the scientific journal "Pain Medicine". The finding underscores the importance of developing rehabilitation interventions targeting pain and lumbopelvic impairments in endometriosis patients.

To explore the effect of endometriosis on hypersensitivity to pain and musculoskeletal impairments in the lumbopelvic region, the team of researchers led by Dr. Francisco Artacho-Cordón conducted a cross-sectional study in 41 women with endometriosis and 25 healthy volunteers. The authors used a numeric rating scale, pressure pain thresholds, the slump test, and the pain catastrophizing scale to assess pain and related catastrophizing thoughts in the participants. They evaluated lumbopelvic muscles using ultrasound imaging, flexor/extensor resistance tests, and the lumbopelvic stability test.

Pain sensitization is defined as the increased responsiveness of pain receptors in the body to stimulus. This means a level of pain response beyond the normal range. 

The results showed that women with endometriosis had higher self-reported pelvic pain and lower pressure pain thresholds than women without the disease. The prevalence of lumbar nerve root impingement or irritation pain and catastrophizing thoughts were also higher in women with endometriosis compared to healthy volunteers.

Results also showed that the thickness of transversus abdominis, the broad muscle sheet found on either side of the abdomen was reduced in women with the disease. The flexor and extensor trunk muscles of these women also had reduced resistance. Finally, the women had lower lumbopelvic stability. Lumbopelvic stability is ensured through the action of deep muscles that stabilize the lumbar spine, the superficial abdominal musculature, and hip muscles that help support and stabilize the pelvis.  The more advanced endometriosis and the more severe pelvic pain were, the worse the results of these parameters were.

The authors concluded that these findings warrant the development of rehabilitation interventions targeting pain and lumbopelvic impairments in women with endometriosis.

Research Source: https://pubmed.ncbi.nlm.nih.gov/33675228/