CASE REPORT Disappearance of phantom limb pain following hyperbaric oxygen therapy NEIL D G BANHAM, SHARON KEETLEY ABSTRACT A 67 year old man with severe peripheral vascular disease and subsequent bilateral below knee amputations was treated with hyperbaric oxygen therapy for non-healing ulcers on his right leg stump. After one treatment on a 10 metre table (105 minutes) his previously severe phantom Umb pain resolved and has since not returned. This has not previously been described and warrants hirther study. Case Report A 67 year old man had bilateral below knee amputation (BKA) for severe peripheral vascular disease with rest pain and foot ulceration. He had a history of hypertension and gout and had smoked for 50 years but was not diabetic. His lipid profile was normal except that he had an elevated non-fasting triglyceride of 2.9 mmol/L (0.3 — 1.8 mmol/L). He had a left BKA on 19 fuly, 1989, then a right BKA on 1 September, 1989 with subsequent revision on 18 September, 1989. After amputation of his left leg he developed almost immediate phantom pain which he described as being much more severe although similar in nature to the rest pain in the other leg. After his right BKA, he developed similar debilitating phantom pain. To relieve this pain, he was taking large amounts of analgesia (up to 10 codeine .30mg/paracetamol 500mg tablets daily) and had been reviewed in the pain clinic. His pain significantly disturbed his sleep and lifestyle. Neil D G Banham MB BS FACEM Senior Registrar in Hyperbaric Medicine Freniantle Hospital, Western Australia and Senior Registrar in Emergency Medicine Rockingham-Kwinana District Hospital, Western Australia Sharon Keetley RN Clinical Nurse Specialist Hyperbaric Medicine Unit Fremantle Hospital, Western Australia After his right BKA he had three non- healing ulcers of his stump which failed to improve over several months, and he was referred for hyperbaric oxygen (HBOI therapy. On 13 December, 1989 he had his first HBO treatment (105 minutes at 10 metres], after which he noted that his phantom pain had completely disappeared. He finished a course of 52 treatments with successful healing of his lesions. He has not had rectm-ence of his phantom pain, over the ensuing 16 months. Discussioa The resolution of this patient's severe bilateral phantom limb pain was very likely secondary to HBO. lb our knowledge, this has not previously been described. A literature search (Medline'*) failed to find any reference to HBO in phantom limb pain. The mechanisms of phantom limb pain are poorly understood. Sherman' has suggested that burning phantom limb pain is probably related to a decrease Ln blood flow within the residual limb, whereas muscle spasm is the postulated mechanism for cramping phantom and stump pain. HBO will reduce peripheral blood flow by vasoconstriction, however this effect is counteracted by high dissolved oxygen content of the blood, resulting in increased tissue oxygenation. HBO will also reduce tissue oedema, which may be a possible factor in phantom limb pain. It is possible that HBO may be effective in phantom limb pain by correcting ischaemia to severed nerve endings which may be surrounded by scar tissue. However, why there should be continued relief of pain after one HBO treatment is uncertain. Relief of chronic limb pain secondary to reflex sympathetic dystrophy (Sudeck's syndrome) has been reported with HBO-- Like phantom limb pain, there have been many therapeutic modalities used in this Emcrsency Medicine UJ^I; ^;.V-,S() 49