CT-guided perineural injections for chronic pelvic pain

Chronic pelvic pain is a disabling condition that affects a large number of men and women. It may occur after a known inciting event, or it could be idiopathic. A common cause of pelvic pain syndrome is neuropathy of the pelvic nerves, including the femoral and genitofemoral nerves, ilioinguinal and iliohypogastric nerves, pudendal nerve, obturator nerve, lateral and posterior femoral cutaneous nerves, inferior cluneal nerves, inferior rectal nerve, sciatic nerve, superior gluteal nerve, and the spinal nerve roots. Pelvic neuropathy may result from entrapment, trauma, inflammation, or compression or may be iatrogenic, secondary to surgical procedures. Imaging-guided nerve blocks can be used for diagnostic and therapeutic management of pelvic neuropathies. Ultrasonography (US)–guided injections are useful for superficial locations; however, there can be limitations with US, such as its operator dependence, the required skill, and the difficulty in depicting various superficial and deep pelvic nerves. Magnetic resonance (MR) imaging–guided injections are radiation free and lead to easy depiction of the nerve because of the superior soft-tissue contrast; although the expense, the required skill, and the limited availability of MR imaging are major hindrances to its widespread use for this purpose. Computed tomography (CT)–guided injections are becoming popular because of the wide availability of CT scanners, the lower cost, and the shorter amount of time required to perform these injections. This article outlines the technique of perineural injection of major pelvic nerves, illustrates the different target sites with representative case examples, and discusses the pitfalls.