Inversion therapy is a type of spinal traction, which involves stretching the spine to relieve pressure on and between compressed discs, according to Indiana University Health. According to Healthline, traction takes pressure off of the compressed discs, straightening the spine and promoting healing. Inversion therapy involves hanging the patient upside down by the ankles or at an angle with the trunk lower than the hips, states IU Health.
As pressure is relieved, the discs are moved away from the nerve roots, according to IU Health, relieving pain, and fluid surrounding the discs may be pulled into them. According to Spine-Health, in theory when the fluid surrounding the compressed discs is pulled in, it pulls some of the herniated or compressed disc material back in with it along with nutrients that promote healing.
According to IU Health and the Mayo Clinic, there is no evidence that inversion therapy provides anything but short-term relief from back pain, and it may be dangerous for those with high blood pressure, heart disease or glaucoma, notes the Mayo Clinic. In addition, Healthline states that spinal traction can sometimes cause muscle spasms and cause pain worse than the original complaint. It may also be dangerous for those with osteoporosis and certain types of cancer.