Presentation on theme: "Case Study: Peripheral Nerve Blocks in Management of Complex Regional Pain Syndrome Shashank Saxena, M.D., Nashaat N. Rizk, M.D., Doris K. Cope, M.D. Department."— Presentation transcript:
Case Study: Peripheral Nerve Blocks in Management of Complex Regional Pain Syndrome Shashank Saxena, M.D., Nashaat N. Rizk, M.D., Doris K. Cope, M.D. Department of Anesthesiology University of Pittsburgh School of Medicine Pittsburgh, Pennsylvania CASE REPORT 1 A 16-year-old healthy female was referred to the pain clinic for persistent right knee pain and for evaluation of complex regional pain syndrome. She had previously been prescribed zolpidem 2.5 mg qhs and gabapentin 100 mg TID with no relief in her symptoms. Pain began after right knee arthroscopy and lateral release for recurrent right patello-femoral ligament performed 1½ months prior to clinic visit. After surgery she noted swelling in the right knee and around the surgical scar. Pain was described as sharp primarily in the right knee with sensitivity to touch. She also complained of shooting pain going down her calf and up to her hip since surgery. In addition there was a burning sensation in the medial aspect of right thigh right leg. On examination she had hyperalgesia, allodynia in the medial aspect of right knee in the saphenous nerve distribution. A saphenous nerve block in the Hunter’s canal (adductor) with 5 cc of 0.5% bupivacaine was performed prior to proceeding with a lumbar sympathetic block. In addition, a compounded topical cream (AGL: amitriptyline 5%, gabapentin 3% and lidocaine 5%) was prescribed for three times per day. Six days later on return visit, her symptoms were much improved. A saphenous nerve block with local anesthetic and 40 mg methylprednisolone acetate was repeated. The patient returned four weeks later with sustained good pain relief until two days prior to return her pain started returned at a lesser intensity. Another saphenous nerve block was administered just with 4 cc 0.5% bupivacaine and 40 mg methylprednisolone acetate. She also increased her AGL cream from once a day to three times a day. In follow up at 1½ months after initial visit, she reported full relief from her symptoms. CASE REPORT 2 A 36-year-old female was referred to the pain clinic for persistent right thigh pain. She sustained injury on her right thigh eleven months prior when a car fell off a jack onto her right thigh. Her injury was complicated by hematoma and subsequent infection and draining sinus which eventually healed with scarring three months after injury. During her visit to the pain clinic, she had hyperalgeisa, allodynia in the skin overlying the scar and the anterior thigh in the saphenous nerve distribution. She also had numerous muscle spasms and electrical jolts running up and down her thigh. MRI of her right thigh showed extensive scar in the medial aspect of the soft tissues about two-thirds of the way down to the bone. Also seen was an area of fibrosis which extends near vastus medialis muscle and runs for about 4-5 cms. EMG showed normal femoral latency. We proceeded with a saphenous nerve block in the Hunter’s canal with 5 cc 0.5% bupivacaine and 20 mg methylprednisolone acetate. We also prescribed KAGL (ketamine, amitryptiline, gabapentin and lidocaine) cream. The patient was seen two weeks later and had mild relief in allodynia and hyperalgesia in the thigh. Another saphenous nerve block with 5 cc 0.25% bupivacaine was performed as well as a scar neuroma injection of 5 cc 0.25% bupivacaine and 20 mg methylprednisolone acetate. Four-week follow-up, the patient had significant improvement in her allodynia and hyperalgesia, as well as improvement in movement of the right knee. Saphenous nerve block and scar neuroma injection were repeated. Pain relief lasted for several weeks and she also reported better motor function of her right thigh. CASE REPORT 2 A 51-year-old male presented to the pain clinic with complaints of left foot pain since 1999. He sustained injury in January 1999 when he fell down on ice. Pain, described as mostly sharp, was confined to the left ankle where he also had swelling. In October 1999 he underwent repair of torn tendon and ligaments in the ankle. His pain persisted, and he developed “electric jolts” sensation from heel to toes and foot cramps. He also expressed feeling cold in the left foot. He underwent calcaneal lateral osteotomy in July 2000. After surgery some of his pain in the ankle improved, but he developed increased sensitivity on the lateral aspect of the foot. In February 2001 he had sural nerve transected just above the ankle in the hope of pain relief. He developed a patch of numbness above the lateral malleolus, but his hypersensitivity and pain persisted with sensitivity to socks and blankets tracking his foot at night. Upon examination, hyperalgesia and allodynia on the lateral aspect of the left foot and a patch of numbness behind the lateral malleolous were noted. He had paraesthesias in the dorsum of left foot. Our tentative diagnosis was CRPS type II of the left foot. We performed a left sural nerve block near the transected nerve using a nerve stimulator using 3 cc 0.25% bupivacaine with 40 mg methylprednisolone acetate. AGL cream was also applied to the skin at the sensitive spots at home. On return one month later, he had no pain or hypersensitivity in his foot. He was advised to continue using the AGL cream and follow up as needed. The CRPS Types I and II as described by the Orlando Consensus Workshop in 1993 1.Abram SE. Neural blockade for neuropathic pain. Clin J Pain 2000;16:S56-S61. 2.Nir-Paz R. Saphenous nerve entrapments in adolescents. Pediatrics 01 Jan 1999;103(1):161-3. 3.Schwartzman RJ. Post injury neuropathic pain syndromes. Med Clin North Am 01 May 1999;83(3):597-626. 4.Reid V. Proximal sensory neuropathies of the leg, Neurol Clin 01 Aug 1999;17(3):655-67, viii. 5.Yaksh TL, Chaplan, SR. Physiology and pharmacology of neuropathic pain. Anesthesiol Clin North America June 1997;15(2). 6.Wasner G, Backonja, Baron R. Traumatic neuralgias: complex regional pain syndromes (reflex sympathetic dystrophy and causalgia): clinical characteristics, pathophysiological mechanisms and therapy. Neurol Clin Nov 1998;16(4). 7.Aeschbach A, Mekhail N. Common nerve blocks in chronic pain management. Anesthesiol Clin North America June 2000;18(2). 8.Stanton-Hicks M. Reflex sympathetic dystrophy: changing concepts and taxonomy. Pain 01Oct 1995;63(1):127-33. 9.Stanton-Hicks M. Complex regional pain syndrome (type I, RSD; type II, causalgia):controversies. Clin J Pain 01 Jun 2000;16(2 Suppl):S33-40. REFERENCESDISCUSSION All patients had allodynia and hyperalgesia commonly associated with CRPS. All had a history of edema/warmth or cold sensation (vasomotor changes). As noted by the CRPS Orlando Consensus Workshop in 1993, a potential cause of symptoms must be ruled out before diagnosing CRPS I or II. We attempted to exclude neuropathy of saphenous and sural nerves, by performing nerve block with local anesthetics and steroid. All patients had good prolonged pain relief. CONCLUSION We conclude that in patients with CRPS like symptoms but predominantly involving single peripheral nerve distribution (irrespective of documented nerve injury) should initially be managed by peripheral nerve blocks with local anesthetic and steroids and adjuvant topical cream applications, prior to resorting to LSB. Performance of peripheral nerve blocks is relatively easy and has a lower complication rate as compared to LSB.