Cryoanalgesic ablation for the treatment of chronic postherniorrhaphy neuropathic pain

Abstract

Background: Chronic postoperative pain has been reported in as many as 62.9% of patients after inguinal herniorrhaphy. Moderate to severe neuropathic pain requiring intervention develops in 2.2% to 11.9% of patients as a result of ileoinguinal and genitofemoral nerve entrapment. Cryoanalgesic ablation has been successful in treating chronic pain from craniofacial neuralgia, facet joint syndrome, and malignant pain syndromes. We report our experience using cryoanalgesic ablation for chronic ileoinguinal and genitofemoral neuralgia after inguinal herniorrhaphy. Methods: Ten patients with ileoinguinal, genitofemoral, or combined neuralgia underwent 12 cryoanalgesic ablations between April 1996 and June 2001. These patients were referred from a multidisciplinary pain clinic, and focused low-volume nerve blocks were used to map nerve involvement preoperatively. After surgical exposure, nerves and surrounding tissues were cooled to -70°C for 3 min using the Lloyd Neurostat. Patients were seen 2 weeks postoperatively and offered monthly follow-up assessments. Results: Nine men and one woman, ages 20 to 54 (mean, 42.6 years) were treated during 58 months, with a mean follow-up period of 8.2 months, for ileoinguinal (n = 4), genitofemoral (n = 1), and combined (n = 5) neuralgia. Patients reported one to five prior herniorrhaphies (mean, 1.8), experienced neuropathic pain 0 to 14 years (mean, 6.3 years), and underwent up to 3 (mean, 1.3) ablative pain procedures before referral. After cryotherapy, patients reported overall pain reduction of 0% to 100% (mean, 77.5%; median, 100%); 80% reported decreased analgesic use, and 90% reported increased physical capacity. Two patients underwent additional cryotherapy, one for incomplete relief and one for recurrent pain, both with 100% efficacy. Wound infection (n = 1) was the only complication. Conclusions: Cryoanalgesic ablation successfully eliminates ileoinguinal and genitofemoral neuralgia in most patients, and should be considered early in the treatment of patients with postherniorrhaphy neuropathic pain.