Spinal manipulation for primary and secondary dysmenorrhoea.

Dysmenorrhoea refers to the occurrence of painful menstrual cramps of uterine origin and is a common gynaecological condition. The efficacy of medical treatments such as nonsteroidal anti-inflammatories (NSAIDs) or oral contraceptive pills (OCPs) is considerable, however the failure rate can still be as high as 20-25% and there are also a number of associated adverse effects. Many women are thus seeking alternatives to conventional medicine. One popular treatment modality is spinal manipulation therapy. There are several rationales for the use of musculoskeletal manipulation to treat dysmenorrhoea. The parasympathetic and sympathetic pelvic nerve pathways are closely associated with the spinal vertebrae, in particular the 2nd-4th sacral segments and the 10th thoracic to the 2nd lumbar segments. One hypothesis is that mechanical dysfunction in these vertebrae causes decreased spinal mobility. This could affect the sympathetic nerve supply to the blood vessels supplying the pelvic viscera, leading to dysmenorrhoea as a result of vasoconstriction. Manipulation of these vertebrae increases spinal mobility and may improve pelvic blood supply through an influence on the autonomic nerve supply to the blood vessels. Another hypothesis is that dysmenorrhoea is referred pain arising from musculoskeletal structures that share the same pelvic nerve pathways. The character of pain from musculoskeletal dysfunction can be very similar to gynecological pain and can present as cyclic pain as it can also be altered by hormonal influences associated with menstruation.