Ultrasound guided percutaneous electro-coagulation of ilioinguinal and iliohypogastric nerves for treatment of chronic groin pain
A 60-year-old male patient was referred from general surgery department for assessment and management of right chronic groin pain. This patient had undergone right inguinal open meshplasty with preservation of ilioinguinal (II), iliohypogastric (IH) and genital nerves 6 months back for reducible right inguinal hernia of 10 months duration. The patient gave no history of right chronic groin pain or any other chronic pain before surgery. He developed chronic groin pain around the incision site, at the root of penis, upper medial part of right thigh and part of right scrotum for past 2½ months for which he was taking analgesics without satisfactory relief. Pain was of burning and pricking character, which was aggravated by walking and sitting. It was interfering with his daily and employment activities. There was no pain at the time of sexual intercourse and ejaculation. Tapping the skin medial to the right anterior superior iliac spine (ASIS) and over areas of local tenderness produced pain (Tinel's test positive).\nHistory and examination were suggestive of neuropathic pain (VAS 7/10) in the territory of II and IH nerves. The plan was to do a diagnostic nerve block with lignocaine followed by chemical neurolysis under ultrasound guidance. The II and IH nerves were identified by ultrasound (Micro MAXX®, Sonosite) with high frequency linear array probe (HFL38/13-6 MHz) in resolution mode, medial and above right ASIS. With the help of colour Doppler, ascending branch of deep circumflex iliac artery was identified to avoid mistaking it for nerve. The diagnostic block was carried out with 2 mL lignocaine 1% for each nerve. Patient had complete pain relief at rest and with activities, confirming it to be neuropathic. Following day chemical neurolysis of both nerves was carried out with ethyl alcohol (1 mL for each nerve) in two target areas (one just medial to ASIS and other one above ASIS) to ensure success of the intervention.\nPatient was reviewed after 4 weeks. Patient had absolute pain relief for one week and only 25% pain thereafter. Pain was still affecting patient's daily activities so diagnostic nerve block was performed again which completely relieved the pain. After discussion with surgeons, patient was told about next option of surgical neurectomy. Another less invasive, percutaneous electrocoagulation of both nerves with the possibility of recurrence of pain was also explained for which patient agreed and gave informed consent. Electrocoagulation of both nerves was planned with 3 Fr Bugbee flexible monopolar cautery electrode (Karl Storz, []). Before performing the procedure on this patient, simulation was done on animal model to study appearance of the electrode tip under ultrasound and energy to be used for electrocoagulation. It was possible to place electrode tip over targets after passing it through epidural needle. The energy of different intensities was applied (10, 15 and 20 W) for one second in fulguration mode to three different targets and coagulation zones were studied. 15 W was found suitable for this procedure. Ultrasound guided electrocoagulation of both nerves was done under spinal anaesthesia []. This procedure was carried out for both nerves in similar two targets to ensure success of the intervention. Patient was given analgesics for 3 days and tablet carbamazepine 100 mg 8th hourly for one week. Four months after procedure, patient had loss of sensation to touch, cold and pain in areas supplied by II and IH nerves. There was effective relief of pain and improvement in quality-of-life.