A treatment option for post-injection sciatic neuropathy: transsacral block with methylprednisolone.

BACKGROUND Accidental intraneural injection induced nerve injury is an iatrogenic tragedy and intramuscular injection (IM) is the most common injury mechanism affecting the sciatic nerve. The most frequent presentation of sciatic nerve injury includes radicular pain and paresthesia with almost immediate onset of variable motor and sensory deficit. OBJECTIVES Intraneural injection is a common injury mechanism of the sciatic nerve and generates neuropathic pain with inflammatory neuritis. Steroids inhibit the production of inflammatory mediators and reduce ectopic discharges on damaged neural membranes. The results of transsacral steroid injection on neuropathic pain in 5 patients with accidental sciatic nerve injury due to intraneural injection were presented in this report. DESIGN Report of 5 cases. DESCRIPTION OF CASES Five patients, 32, 34, 45, 54 and 70 years old respectively, complaining of severe neuropathic pain, paresthesia and progressive weakness of the lower extremity with difficulty in walking secondary to gluteal injection were admitted to the clinic. The symptoms were resistant to drug therapies. Electromyography disclosed axonal damage of the sciatic nerve. The initial examination of the patients revealed a Numeric Rating Scale (NRS) of 10, 10, 9, 9, and 10 respectively. RESULTS Diagnostic block was performed through the unilateral S1-S2-S3 sacral foramina with 22-G spinal needle by 5 mL 1% lidocaine into each foramen. NRS scores decreased to 1, 2, 2, 2 and 1, respectively. One week later, the patients were administered 80 mg methylprednisolone with 1% lidocaine in 15 mL solution shared equally in each foramen. The patients were checked one month after therapeutic block and a full recovery was achieved in all patients. CONCLUSION The neuropathic pain due to accidental intraneural injection of the sciatic nerve would be an acceptable indication for transsacral nerve block with corticosteroids in the treatment of sciatic neuropathic pain symptoms.