285 Paiq 32 (1988) 285-287 Elsevier PA1 01195 Clinical Note Disappearance David Department of phantom pain after focal brain infarction Yarnitsky, Stephen A. Barron and Ephraim Bental of Neurology, Rambam Medical Center and Faculty of Medicine, Technion-Israel Institute of Technology, Haifa (Israel) (Received 15 September 1987, accepted 27 November 1987) Summary A patient with hemiplegia and hemihypoesthesia is presented in whom preexisting phantom limb pain disappeared with the appearance of a stroke localized by CT scan to the posterior internal capsule. Differentiation between the cutaneous sensation and the sensation of phantom limb pain that appeared later seems to support the assumed existence of a polysynaptic sensory pathway that conveys the sensations of deafferentation. Key words: Stump pain; Phantom pain; Spino-thalamic tract The disappearance of stump pain and phantom limb pain following cerebral lesions has been described in a few patients, but without CT scan evidence of the lesion [1,2,5]. We describe a patient with localized infarction of the posterior internal capsule who had full return of cutaneous sensation yet never again experienced phantom or stump pain. Report of a case A 72-year-old man was hospitalized because of sudden onset of right hemiplegia accompanied by a focal seizure. His past history included ischemic heart disease, epileptic seizures over the prior 4 years, and right below-knee amputation 5 years Correspondence to: Dr. David Yamitsky, Department of Neurology, Good Samaritan Hospital, 1015 N.W. 22nd Avenue, Portland, OR 97210, U.S.A. 0304-3959/88/$03.50 0 1988 Elsevier Science Publishers earlier because of peripheral vascular disease. Following his amputation, he had constant, severe pain in the stump and a painful phantom. Both stump and phantom pain ceased when he had the cerebral infarction. Examination revealed mild right hand weakness and severe leg weakness, evolving to complete paralysis within a day, and right hemihypoesthesia. His motor function gradually improved, and sensation returned to normal at the end of 2 months. At that time, there were no side-to-side differences in touch-pressure sensation as measured with a commercial esthesiometer, in vibration perception as measured with an automated device (Biomedical Instruments Co.) at 100 Hz, in pain perception as measured with a semiquantitative test of pin-prick perception, nor in joint position sense as assessed by the usual clinical technique. Stump pain and phantom pain did not reappear during a 7-month follow-up period. A CT scan disclosed an infarction in the posterior limb of the internal capsule and the lenticular nucleus (Fig. l), probably interrupting the thalamo-cortical sensory fibers. B.V. (Biomedical Division) 286 levels, via either rhizotomy, dorsal root entry zone lesions, cordotomy or thalamotomy. ‘Spontaneous’ interruption of the pathway by disease states such as stroke or disk herniation might also be expected to cause relief, at least transiently. Indeed, Head and Holmes [5], Bornstein [2] and Appenzeller and Bicknell [l] reported several cases in which parietal lobe lesions caused both hemihypoesthesia and disappearance of phantom limb pain. To our knowledge, the case presented here is the first to be reported with CT evidence of a lesion and its location. Nathan [9], Loeser [7] and others have suggested the existence of an ascending polysynaptic pathway that conveys the sensations of deafferentation in contrast to the spino-reticula-thalamic tract which transmits normal sensations. Such a pathway might explain the relative failure of surgical treatment for the relief of phantom limb pain, when the spino-thalamic tract is interrupted but pain continues to travel through the additional tract. Our case seems to further support this assumption. The reversal of hypoesthesia with permanent loss of the phantom pain which was demonstrated in our patient is in keeping with the suggestion of two different sensations. The localization of the infarct in our patient suggests that this differentiation exists also at the level of the thalamo-cortical fibers. various Fig. 1. CT scan ot bran ctemonstratmg hypodenstty in posterior limb of internal capsule and lenticular nucleus. Discussion References Stump pain and phantom pain are common complications of amputation, especially when pain was present previously. Frequency of occurrence is estimated to be up to 80% of amputees [6]. The pathophysiology of these pains is not well understood. Wall [ll] suggested that it is related to post-amputation changes in the cut peripheral nerve itself or in the spinal cord, while others suggest changes in higher structures such as the thalamus or cortex [8]. Various medical [3], physical [4] and surgical [lo] therapies have been suggested, but none with clear, permanent success. The surgical approach consists of interruption of the neural pathway at 1 Appenzeller, 0. and Bicknell, J.M.. Effects of nervous system lesions on phantom experience in amputees, Neurology, 19 (1969) 141-146. 2 Bomstein, B., Sur le ph6nombne du membre phantame, Enctphale, 38 (1949) 32 [cited in ref. 11. 3 Danke, F., Drug treatment of phantom and stump pain. In: J. Siegfried and M. Zimmermann (Eds.), Phantom and Stump Pain, Springer, Berlin, 1981, pp. W-92. 4 Gesster, M., Struppler, A. and Oettinger, B., Treatment of phantom pain by TNS of the stump, the limb contralateral to the stump and the other extremities. In: J. Siegfried and M. Zimmermann (Eds.), Phantom and Stump Pain, Springer, Berlin, 1981, pp. 93-98. 5 Head, H. and Holmes, G., Sensory disturbances from cerebral’lesions, Brain, 34 (1911) 102 [cited in ref. I]. 287 6 Jensen, T.S., Krebs, B., Nielsen, J. and Rasmussen, P., Immediate and long-term phantom limb pain in amputees: incidence, clinical characteristics and relationship to preamputation limb pain, Pain, 21 (1985) 267-278. 7 Loeser, J.D., Definition, etiology and neurological assessment of pain originating in the nervous system following deafferentation. In: J.J. Bonica, U. Lindblom and A. Iggo (Eds.), Advances in Pain Research and Therapy, Vol. 5, Raven Press, New York, 1983, pp. 701-711. 8 Melzack, R., Phantom limb pain: implications for treatment of pathological pain, Anesthesiology, 35 (1971) 409-419. 9 Nathan, P.W., Reference of sensation at the spinal level, J. Neural. Neurosurg. Psychiat., 19 (1956) 88-100. 10 Siegfried, J. and Cetinalp, E., Neurosurgical treatment of phantom limb pain: a survey of methods. In: J. Siegfried and M. Zimmermann (Eds.), Phantom and Stump Pain, Springer, Berlin, 1981, pp. 148-155. 11 Wall, P.D., On the origin of pain associated with amputation. In: J. Siegfried and M. Zimmermann (Eds.), Phantom and Stump Pain, Springer, Berlin, 1981, pp. 2-14.