Pelvic Pain Treated With MR-guided Cryoanalgesia

Pelvic pain syndromes including meralgia paresthetica, inguinodynia, and deep gluteal syndrome and others, which are caused by nerves including the the lateral femoral cutaneous nerve (LFCN), genitofemoral nerve (GFN), ilioinguinal nerve (IIN), iliohypogastric nerve (IHN), pudendal nerve (PN), obturator nerve (ON), posterior femoral cutaneous nerve (PFCN), and others, have a high prevalence of up to 8% in the general population and up to 50% following pelvic trauma and pelvic surgery, including episiotomy, orthopedic instrumentation and surgical hernia repair. While medical management is the initial therapeutic step, it is often ineffective with surgical decompression and resection of the putative nerves being the ultima ratio. Cryoablation of sensory nerves at temperatures of approximately 40 degrees Celsius and below (Cryoanalgesia) can induce long-lasting nerve conduction blocks with resultant pain relief for several months, which could be an effective treatment option for a large number of patients in this group before, instead of, and after failed surgical treatment. Cryoablation affords several advantages over other thermal or chemical ablation techniques, including direct visualization of the ablation zone, decreased intraprocedural and postprocedural pain, and the ability to simultaneously use multiple probes in variable configurations to create tailored additive overlapping ablation zones. In contrast to surgical or heat-mediated ablation, cryoablation does not disrupt the acellular epineurium or perineurium, which reduces the risk of neuroma formation and may allow eventual nerve regeneration, after which the cryoanalgesia can be repeated. Interventional MR neurography at 3 Tesla describes the combined use of high-resolution MRI for the visualization of smallest nerves that are located deep inside the pelvis, targeting, placement of needles and probes, and process monitoring, such as growth of the ice ball and relationship to the target nerves. The use of interventional MR neurography is thus ideally suited to perform cryoanalgesia with the highest technical accuracy and safety. The objective of this study is to evaluate the effectiveness of MR neurography-guided cryoanalgesia for the treatment of pelvic and associated pain syndromes.