RD is a middle-aged ex-fireman who injured his hip and sacro-iliac joint in a fall. We treated his pain with SI joint injections and epidurals, but recently he began to talk about sexual dysfunction. He consulted multiple specialists without any answers. He finally asked me if it could be due to his back. His MRI showed no severe issues that could cause sexual dysfunction, so we began looking for other sources. In particular, he was very tender over the sacrospinous ligament, which travels from the bottom of the tailbone (sacrum) to the bottom part of the pelvic bone. Once I looked it up, it became clear that the pudendal nerve (that supplies the penis) travels under this ligament (ligament in red above, star shape at site where nerve gets entrapped). It was worth a shot (literally) as he had no other options and cutting the ligament would destabilize his pelvis and SI joint complex. Under ultrasound guidance we localized his sacrospinous ligament and injected a small amount of anti-inflammatory. When I saw him two weeks later, his sexual dysfunction was gone, meaning that it’s likely the nerve was getting entrapped. While this may be a rare problem, the solution in this one patient was simple.
