An elastomeric pump for epidural infusions in an outpatient setting is a novel, effective treatment option for complex regional pain syndrome (CRPS), new research suggests.
Elastomeric pumps are commonly used in the outpatient setting for peripheral nerve blocks, palliative care and postoperative pain, but have not been described for use with epidural infusions for CRPS, according to Aram Shahinyan, MD, lead study author and anesthesiology resident at Geisinger Medical Center, in Danville, Pa.
“The cervical epidural infusion in the outpatient setting is a modality that hasn’t been studied in CRPS, and we have a good track record of this modality being used in Geisinger Medical Center for years,” Dr. Shahinyan said. He presented a case study showing successful treatment of type 1 CRPS using this new method.
“Our patient was a 23-year-old gentleman diagnosed with CRPS type 1 two months after sustaining injury while cutting meat at work,” Dr. Shahinyan said. “It resulted in incomplete fracture of the left thumb proximal phalanx with extensor tendon injury.”
The patient’s initial pain scores were 5 to 6 out of 10 on a numeric rating scale. He described the pain as constant and stabbing, and increased with any activity, researchers reported. A physical examination showed that the thumb had healed well and the patient exhibited hypersensitivity and allodynia to light touch and pinprick over the right hand and radial aspect of the wrist.
The patient’s pain did not improve with physical therapy, oxycodone-acetaminophen as needed or a three-week trial of pregabalin (Lyrica, Pfizer), so the researchers suggested alternative treatments such as a stellate ganglion block. Dr. Shahinyan said the patient “elected to try a cervical epidural infusion in place of the stellate ganglion block” after they discussed the risks and benefits of the alternative treatment options.
“The procedure is a cervical epidural placed under fluoroscopy utilizing an 18-gauge Tuohy needle,” Dr. Shahinyan said.
The patient was first placed in a prone position and the epidural space was accessed at the C7-T1 level using a left paramedian approach under fluoroscopy. They then injected 5 mL of 1% lidocaine into the epidural space and advanced a 20-G catheter. The catheter was advanced 5 cm past the tip without resistance and the placement was checked under fluoroscopy. The procedure was well tolerated and the patient’s vital signs remained stable throughout the procedure, according to the researchers.
The epidural catheter was connected to an elastomeric pump containing 270 mL of 0.05% bupivacaine and set at a rate of 10 mL per hour when open. The patient was instructed to turn on the pump every four hours as needed to obtain pain relief, but not for longer than three hours at a time.
The patient reported insufficient pain relief during his initial follow-up on postoperative day (POD) 4, so the concentration of bupivacaine was increased to 0.1%. The patient reported mild neck discomfort on POD 7, but the catheter site was clean. His pain scores improved (2-3/10). By POD 11, the patient reduced catheter use to three to four times daily, and his scores improved to 1 to 2 out of 10.
“On postoperative day 15, the patient was almost pain-free. On day 16, he didn’t have any pain and the infusion was stopped by him and we removed the catheter on day 18,” Dr. Shahinyan said. “On the seven-month post-procedure follow-up, the patient was pain-free and he returned to work on full duty.”
Dr. Shahinyan said more research is needed to test the efficacy of this modality for the treatment of CRPS. The findings were presented at the 2016 New York School of Regional Anesthesia’s annual symposium (poster P7).
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