Epidural catheterization with a subcutaneous injection port for the long-term administration of opioids and local anesthetics to treat zoster-associated pain -a report of two cases-
A 64-year-old man (height 160 cm, weight 62 kg) with a 10-year history of diabetes mellitus, who had undergone a left pneumonectomy due to squamous cell carcinoma in his left upper lobe, presented with pain along the incision site (corresponding to a T5-6 dermatomal distribution) for 20 days. The pain began 3 days before the appearance of vesicles, which appeared 20 days after the pneumonectomy, and a physical examination revealed allodynia and hyperalgesia at the incision site. Following the diagnosis of acute herpes zoster, he was treated with 1000 mg/day of acyclovir intravenously for 5 days and with 150 mg/day of pregabalin orally for 3 weeks. Three weeks after pain onset, he was referred to our department for treatment because the pain persisted after the skin lesions had healed. A thoracic epidural block at the T6-7 interspace with a single dose of 10 ml of 0.1% bupivacaine and 10 mg of triamcinolone resulted in complete pain relief and a bilateral sensory block of the T5-8 dermatomes as determined by the pinprick method. However, the pain relief lasted less than 3 days. At this point, he was scheduled to receive 4 cycles of adjuvant chemotherapy. Following the decision that no additional thoracic epidural blocks were possible during the chemotherapy, epidural catheter placement and the subcutaneous implantation of an injection port were recommended. The same procedure as that used in the previous case was performed at the T10-11 interspace with the catheter tip located at the T5 (). Immediately after the completion of the procedure, the epidural infusion device containing 20 mg of morphine, 20 ml of 0.5% bupivacaine and 210 ml of normal saline (a total volume of 250 ml) was programmed to deliver at a basal rate of 2 ml/hr and delivered through a port needle. The side effects and complications associated with the procedure and epidural medications were monitored closely in the general ward. Oral medications consisting of 150 mg/day of pregabalin and 10 mg/day of amitriptyline were maintained. A stool softener and a bowel stimulant were added to the routine medications to prevent opioidinduced constipation. The epidural infusion pump was changed, and the pain intensity was evaluated every 5 days. One week after the procedure was completed, 4 cycles of adjuvant chemotherapy consisting of the daily intravenous administration of paclitaxel (175 mg/m2 × 0.9) and cisplatin (75 mg/m2 × 0.9) began, with 3 weeks between each cycle.\nThe analgesic regimen decreased the visual analog scale pain score from 8 or 9 to 1 or 2. The lower pain scores were maintained until the removal of the subcutaneous port and the epidural catheter. Leukocytosis occurred during each chemotherapy cycle, but no epidural catheter infection-associated signs or symptoms presented. During the chemotherapy, no complications related to the subcutaneous port or the epidural catheter were noted. Due to the obstruction of the epidural catheter identified 120 days after the procedure, the catheter and subcutaneous port were removed. After removal, the patient reported a visual analog scale pain score of 1 or 2. Oral pregabalin and amitriptyline were tapered off uneventfully 1 month after the removal. Although the decreased visual analog pain scores of the zoster-associated pain were maintained during the 6-month follow-up period after the removal, opioid therapy (20 to 80 mg of oxycodone per day) was initiated after a new onset of cancer-related pain (left lower extremity pain). Until his death (16 months after the removal), no symptoms or signs of herpes zoster were reported.