(228) Repetitive paravertebral nerve block using a mixture of ketamine, bupivacaine and methylprednisolone for pain relief in intractable post herpetic neuralgia

Abstract

We present a case of postherpetic neuralgia (PHN) treated successfully with repetitive paravertebral blocks (PVB) with bupivacaine, ketamine and methylprednisolone. A 65-yr-old male patient, ASA II, weight 55 kg, previously healthy was referred with 24 month left sided parietal chest pain diagnosed as PHN with 8–9/10 on VAS scale. Previous pain treatment included non-steroidal anti-inflammatory drugs and tramadol, combined with oral oxcarbazepine 600 mg per day and amitryptyline 75 mg per day with no improvement. A few months later, gabapentin was added at a dose of 300 mg three times per day that was increased gradually to 1800 mg per day over a 6 month period. Upon presentation, the patient was still complaining of persistent pain with a VAS 8-9/10 in the left thoracic region mainly at T4 extending to T7 associated with mood changes and sleep disturbance. Physical examination revealed an allodynia and hyperaesthesia of the corresponding dermatomes. A unilateral left sided paravertebral block at T4–T5 levels was performed with 20 ml of bupivacaine 0.125% in ketamine 25 mg and methylprednisolone 80 mg. Sedation was achieved with midazolam 2-4 mg. Three more PVB injections were given on weekly interval with the same mixture in 40 mg of methylprednisolone. Blood pressure, ECG, and SpO2 were continuously monitored throughout the procedure and for two hours in the recovery room. There were no serious complications. The patient obtained satisfactory pain relief (VAS 3) over a 6 month follow-up period. Our report showed that weekly paravertebral injections of a mixture of bupivacaine, ketamine and methylprednisolone for 4 weeks resulted successfully in sustained pain relief for PHN.