Ilioinguinal, Iliohypogastric and Genitofemoral nerve blocks
Nerve blocks of the Ilioinguinal, Iliohypogastric and Genitofemoral nerves have been used for both diagnostic and therapeutic purposes in the diagnosis and treatment of chronic post hernia surgery pain. Historically, these nerve blocks were performed using a blind technique, using anatomic landmarks as guidance for needle placement.
Recent advances in ultrasound technology and its use in regional anesthesia have enabled practitioners to perform these blocks under a direct visualization, with successful outcomes reducing risk of intraperitoneal needle placement and allowing for a smaller volume of injectate due to improved accuracy.
In a recent report by Thomassen et al the authors found ultrasound-guided nerve blocks to be effective in treating of chronic post hernia surgery pain with successful prolonged pain relief after a median follow-up time of 20 months.
Pulsed radiofrequency ablation of inguinal nerves
If nerve blocks have been performed and provided significant analgesia but did not provide long-term relief, neuroablative techniques such as chemical neurolysis, cryoablation, and pulsed radiofrequency (PRFL) ablation may be considered for longer-lasting effect.
The use of pulsed radiofrequency ablation in the treatment of chronic post hernia repair pain has been reported in multiple case series as well as in a recent systematic review. PRF ablation delivers high intensity currents in pulses, which allows for heat (typically 42°C) to dissipate during the latent phase so that neurodestructive temperatures are not obtained, thus lowering the risk of neuroma formation, neuritis-type reaction, and deafferentation pain. This mild heating of the nerve tissue is thought to temporarily block nerve conduction; however, the exact mechanism by which PRF ablation provides analgesia is unclear.
Pulsed radiofrequency treatment of ilioinguinal nerve, iliohypogastric nerve and genito femoral nerve under real time ultrasound guidance can provide long term pain relief in patients with chronic groin pain after inguinal hernia surgery.
Dorsal root ganglion pulsed radiofrequency
In refractory cases, nerve root blocks at T12, L1 and L2 levels can be offered, followed by pulsed radiofrequency treatment targeting the dorsal root ganglions at these levels. This can provide sustained pain relief in some cases.
Neuromodulation techniques, either peripheral nerve field stimulation (PNFS) or spinal cord stimulation (SCS), may be considered for use in a select group of patients when all other conventional treatments have failed.
Surgical pain management
While the majority of patients with chronic post surgical pain can be managed with pharmacologic, interventional, and behavioral measures, those refractory to a systematic regimen of diagnostic and interventional measures may be considered for operative remediation. Successful outcomes, however, are entirely dependent upon choosing patients with discrete, neuroanatomic problems that may be corrected with surgery. Failure of conservative measures, in and of itself, is not an indication for further surgery.