Genitofemoral neuralgia is a common cause of lower abdominal and pelvic pain. Genitofemoral nerve block is a simple technique that can produce dramatic relief for patients with genitofemoral neuralgia. Patients with a positive response to genitofemoral nerve block should be considered for ultrasound-guided genitofemoral nerve ablation as this technique may provide long-term pain relief. At Pain Spa Dr. Krishna performs genitofemoral nerve block and ablation under real-time ultrasound guidance, using state of the art equipment. This ensures 100% accuracy and our complication rates are extremely low.
The genitofemoral nerve arises from fibers of the L1 and L2 nerve roots. It passes through the substance of the psoas muscle, where it divides into a genital branch and a femoral branch. The femoral branch passes beneath the inguinal ligament along with the femoral artery and provides sensory innervation to a small area of skin on the inside of the thigh. The genital branch passes through the inguinal canal to provide innervation to the round ligament of the uterus and labia majora in women. In men, the genital branch of the genitofemoral nerve passes with the spermatic cord to innervate the cremasteric muscles and provide sensory innervation to the bottom of the scrotum.
The genitofemoral (L1–L2) nerve passes through and along the anterior surface of the psoas major muscle, and it divides into genital and femoral branches above the inguinal ligament. Its genital branch travels with the spermatic cord and innervates the genitalia inferior to the area supplied by the ilioinguinal nerve.
Injections are generally avoided in patients with systemic infection or skin infection over puncture site, bleeding disorders or coagulopathy, allergy to local anaesthetics or any of the medications to be administered. Pulsed radiofrequency ablation is contraindicated in patients with a cardiac pacemaker or any other neuromodulation implants.
The clinical application of pulsed radiofrequency (PRF) by interventional pain physicians for a variety of chronic pain syndromes, including genitofemoral neuralgia, is growing. As a minimally invasive percutaneous technique with none to minimal neurodestruction and a favourable side effect profile, use of PRF as an interventional neuromodulatory chronic pain treatment is appealing.
The mechanism of action underlying the utility of PRF in interventional pain medicine is uncertain. Unlike conventional continuous radiofrequency ablation, whose pain relief effects are mediated through non-selective, temperature-dependent, neurodestruction, PRF is widely believed to act through a temperature- independent, neuromodulatory process, altering synaptic transmission and pain signaling via the emission of electric fields, with none to minimal resultant tissue destruction. Given the nondestructive nature of PRF, deafferentation pain—a feared complication of continuous radiofrequency ablation—is not a potential risk.
Patients who get temporary pain relief from genitofemoral nerve blocks may be suitable for genitofemoral nerve ablation procedure (pulsed radiofrequency treatment). This is likely to provide longer-term pain relief.
The procedure is done on an outpatient basis. The procedure is performed under ultrasound guidance to ensure the accuracy of needle placement. Specialized equipment including radiofrequency machine, probe, and RF needle is utilized to heat the nerve up to a temperature of 42°C. Generally local anaesthetic is injected around the nerve following nerve ablation. The local anaesthetic is responsible for immediate pain relief, whereas pulsed radiofrequency takes 4 to 6 weeks to provided sustained pain relief. Pain relief from pulsed radiofrequency ablation of the genitofemoral nerve can last between 6 months to 24 months.
Complications are rare, particularly if the injections are performed using a precise needle-positioning technique. Possible complications include bruising, infection, hematoma, nerve injury and reaction to the injectates. Infection can be avoided with appropriate aseptic precautions. Severe allergic reactions to local anaesthetics are uncommon. Steroid injections may produce local reactions, occurring most often immediately after injection. These local reactions last for 24 to 48 hours and are relieved by application of ice packs. Post-procedural pain flare-up may occasionally occur and may be treated with painkillers. Neurological complications including paraesthesias and numbness have been described but are rare.