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A mechanism of new pain following cordotomy; reference of sensation
Pain, 30 (1987) 89-91 Elsevier
89
PAI 01091
Clinical Note
A mechanism of new pain following cordotomy; reference of sensation Takumi
Nagaro,
Shigeo Kimura
and Tatsuru Arai
Department of Anesthesiology, Ehime Universiq School of Medicine, Shigenobu-cho, Omen-gun, Ehime-ken 791-02 (Japan) (Received 28 January 1987, accepted 16 March 1987)
An antero-lateral cordotomy was performed on a 62-year-old man who had been Summpry suffering from intractable right chest pain caused by lung cancer. Six hours after the cordotomy a new pain occurred in an analogous part of the body on the opposite side; the intensity increased gradually and it became as severe as the original within 1 week. Reference of sensation from analgesic area of cordotomy to the opposite side of the body was induced by noxious stimuli. Intrathecal phenol block to the nerves conveying the cancer pain abolished the new pain and the reference of sensation from this blocked area, though it remained unchanged in other analgesic areas of cordotomy. This substantiates that the new pain was a reference of the original cancer pain. Key words: Cancer pain; Cordotomy; Reference of sensation; Reference of pain
Introduction Cordotomy is an effective and useful technique for treating cancer pain localized on one side of the body. One peculiar but interesting phenomenon after the cordotomy is that in spite of complete elimination of the pain, a new pain sometimes occurs on the opposite side of the body where none had been felt before the cordotomy [l-4]. Nathan [1,2] speculated that this phenomenon was caused by the same mechanism known as ‘reference of sensation (allochiria)’ following division or transection of the spinal cord. Not all people [5] agree with this theory, and some [4] believe that the new pain is originated from some pre-existing organic lesion but had been masked by the cancer pain. We have recently experienced a case which substantiates the hypothesis of Nathan.
Correspondence to: Dr. T. Nagaro, Dept. of Anesthesiology, Ehime University School of Medicine, Shigenobu-cho, Onsen-gun, Ehime-ken 791-02, Japan. 0304-3959/87/$03.50
0 1987 Elsevier Science Publishers B.V. (Biomedical Division)
90
Report of a case
A 62-year-old man was referred to our pain clinic for the treatment of intractable right chest pain caused by lung cancer. The patient had been on chemotherapy for 5 months with only deterioration of the disease and increased pain. He complained of unendurable deep burning pain in the right side of chest and back, which corresponded to the region innervated with Th,-Th,. Chest roentgenogram revealed right lower lobe atelectasis and right side pleural effusion, from which adenocarcinema cells were demonstrated. Left percutaneous cordotomy by thermocoagulation technique was performed at C,-C, intervertebral space resulting in analgesia immediately throughout the right side of the body below the 1st thoracic dermatome. Six hours after the cordotomy the patient became aware of pain in the left side of chest, in the area just mirroring the original right side chest pain. This new pain was similar in character but milder. The intensity of the pain increased gradually and it became as severe as the original one within 1 week. No pathologic changes were observed in the left side of the chest with roentgenograms and CT scannings. Pinching the skin in the analgesic area (right side of the body) induced pain in the left side of the chest, but pin-pricking and non-noxious stimulations such as touching and scrubbing did not. Pressure on the right side of chest or putting the patient in an upright position, which had resulted in worsening of original pain, made the new pain worse as well. Diclofenac sodium suppository, i.m. pentazocine and epidural morphine, effective for original pain, were also effective for the new pain. From this we presumed that the new left side chest pain was originating from the right side cancer pain. Intrathecal phenol block was carried out on the nerves conveying original cancer pain in order to stop the entrance of the pain into spinal cord. In the right semilateral position 0.4 ml of 10% phenol in glycerine was injected at Th,-Th, interspace, resulting in anesthesia between the 5th and 10th thoracic dermatomes on the right side. The new pain on the left side of chest disappeared immediately. The reference of the sensation from right to left side of the body with the application of noxious stimuli disappeared in the area anesthetized by phenol block but remained unchanged in the rest of the analgesic area of cordotomy. Discussion
After the antero-lateral cordotomy of the spinal cord has been done in man, loss of sensation of pain and temperature caudal to the region is to be expected. In a small proportion of patients, painful or thermal stimuli applied within analgesic parts of the body arouse a sensation, which is felt not at the place actually stimulated but in a normally innervated part of the body [l-3]. The mechanism underlying this reference of the sensation was considered to be due to the conduction of the sensation via chains of short neurons in the spinal cord [1,3]. With this hypothesis Nathan [l] tried to account for all the features of the spread and pattern of reference of sensation; spread across to the analogous place on the opposite side
91
of the body, spread cranially or caudally, lack of correct local signs, the fact that the reference is always to the region adequately innervated by spinothalamic tract, and the fact that the harder the stimulation the further the sensation is referred. The conduction of the sensation via chains of short neurons was considered to be associated with a state of hyperexcitability of the central nervous system, which was assumed to be induced by the division of large numbers of nerves or division of an algesic tract inside the central nervous system. After cordotomy, usually for the treatment of intractable cancer pain, sometimes a new pain occurs on the opposite side of the body without applying any painful stimuli to the analgesic part of the body [1,2,4]. Nathan [1,2] ascribed this to the reference of the original pain sensation. Although this assumption seems reasonable nobody has confirmed it. In our case after cordotomy a new pain occurred in the analogous part of the body on the opposite side, and at the same time reference of the sensation from analgesic part of the body to the opposite side was observed. As soon as the nerves conveying cancer pain to the spinal cord were blocked by intrathecal phenol injection, the new pain on the left side of chest was abolished, and at the same time the reference of the sensation from the area anesthetized by phenol block disappeared, though it remained unchanged in other analgesic parts of cordotomy. This confirmed that the new pain was a reference from the original right chest pain. So far we have performed 33 unilateral cordotomies on patients suffering from cancer pain restricted to one side of the body. In 21 cases, a new pain appeared on the opposite side of the body within 1 week after cordotomy. In 4 of the 21 cases, the new pain was considered to be caused by reference of the original pain, because no organic changes were found on the side of new pain, and the reference of sensation from analgesic to opposite side of the body was observed. (The reported case here is one of these.) In 8 other cases reference of the original pain was suspected as a cause though the reference of sensation could not be induced. In the remaining 9 cases organic changes which could cause pain were found on the side of new pain, though it was not determinable if they actually caused the new pains. We concluded that the reference of sensation is one definite cause of the phenomenon in which a new pain occurs on the opposite side to the original cancer pain after a cordotomy, as is substantiated by our report. References 1 Nathan, P.W., Reference of sensation at the spinal level, J. Neurol. Neurosurg. Psychiat., 19 (1956) 88-100. 2 Nathan, P.W., Results of antero-lateral cordotomy for pain in cancer, J. Neurol. Neurosurg. Psychiat., 26 (1963) 353-362. 3 Ray, B.S. and Wolff, H.G., Studies on pain ‘spread of pain;’ evidence on site of spread within the neuraxis of effects of painful stimulation, Arch. Neurol. Psychiat. (Chic.), 53 (1945) 257-261. 4 Ventafridda, V., De Conno, F. and Fochi, C., Cervical percutaneous cordotomy. In: J.J. Bonica, V. Ventafridda and C.A. Pagni (Eds.), Advances in Pain Research and Therapy, Vol. 4, Raven Press, New York, 1982, pp. 185-198. 5 White, J.C. and Sweet, W.H., Spinothalamic tractotomy: complications, technique and review of new alternative procedures. In: J.C. White and W.H. Sweet (Eds.), Pain and the Neurosurgeon: a Forty-Year Experience, Thomas, Springfield, IL, 1969, pp. 748-749.
89
PAI 01091
Clinical Note
A mechanism of new pain following cordotomy; reference of sensation Takumi
Nagaro,
Shigeo Kimura
and Tatsuru Arai
Department of Anesthesiology, Ehime Universiq School of Medicine, Shigenobu-cho, Omen-gun, Ehime-ken 791-02 (Japan) (Received 28 January 1987, accepted 16 March 1987)
An antero-lateral cordotomy was performed on a 62-year-old man who had been Summpry suffering from intractable right chest pain caused by lung cancer. Six hours after the cordotomy a new pain occurred in an analogous part of the body on the opposite side; the intensity increased gradually and it became as severe as the original within 1 week. Reference of sensation from analgesic area of cordotomy to the opposite side of the body was induced by noxious stimuli. Intrathecal phenol block to the nerves conveying the cancer pain abolished the new pain and the reference of sensation from this blocked area, though it remained unchanged in other analgesic areas of cordotomy. This substantiates that the new pain was a reference of the original cancer pain. Key words: Cancer pain; Cordotomy; Reference of sensation; Reference of pain
Introduction Cordotomy is an effective and useful technique for treating cancer pain localized on one side of the body. One peculiar but interesting phenomenon after the cordotomy is that in spite of complete elimination of the pain, a new pain sometimes occurs on the opposite side of the body where none had been felt before the cordotomy [l-4]. Nathan [1,2] speculated that this phenomenon was caused by the same mechanism known as ‘reference of sensation (allochiria)’ following division or transection of the spinal cord. Not all people [5] agree with this theory, and some [4] believe that the new pain is originated from some pre-existing organic lesion but had been masked by the cancer pain. We have recently experienced a case which substantiates the hypothesis of Nathan.
Correspondence to: Dr. T. Nagaro, Dept. of Anesthesiology, Ehime University School of Medicine, Shigenobu-cho, Onsen-gun, Ehime-ken 791-02, Japan. 0304-3959/87/$03.50
0 1987 Elsevier Science Publishers B.V. (Biomedical Division)
90
Report of a case
A 62-year-old man was referred to our pain clinic for the treatment of intractable right chest pain caused by lung cancer. The patient had been on chemotherapy for 5 months with only deterioration of the disease and increased pain. He complained of unendurable deep burning pain in the right side of chest and back, which corresponded to the region innervated with Th,-Th,. Chest roentgenogram revealed right lower lobe atelectasis and right side pleural effusion, from which adenocarcinema cells were demonstrated. Left percutaneous cordotomy by thermocoagulation technique was performed at C,-C, intervertebral space resulting in analgesia immediately throughout the right side of the body below the 1st thoracic dermatome. Six hours after the cordotomy the patient became aware of pain in the left side of chest, in the area just mirroring the original right side chest pain. This new pain was similar in character but milder. The intensity of the pain increased gradually and it became as severe as the original one within 1 week. No pathologic changes were observed in the left side of the chest with roentgenograms and CT scannings. Pinching the skin in the analgesic area (right side of the body) induced pain in the left side of the chest, but pin-pricking and non-noxious stimulations such as touching and scrubbing did not. Pressure on the right side of chest or putting the patient in an upright position, which had resulted in worsening of original pain, made the new pain worse as well. Diclofenac sodium suppository, i.m. pentazocine and epidural morphine, effective for original pain, were also effective for the new pain. From this we presumed that the new left side chest pain was originating from the right side cancer pain. Intrathecal phenol block was carried out on the nerves conveying original cancer pain in order to stop the entrance of the pain into spinal cord. In the right semilateral position 0.4 ml of 10% phenol in glycerine was injected at Th,-Th, interspace, resulting in anesthesia between the 5th and 10th thoracic dermatomes on the right side. The new pain on the left side of chest disappeared immediately. The reference of the sensation from right to left side of the body with the application of noxious stimuli disappeared in the area anesthetized by phenol block but remained unchanged in the rest of the analgesic area of cordotomy. Discussion
After the antero-lateral cordotomy of the spinal cord has been done in man, loss of sensation of pain and temperature caudal to the region is to be expected. In a small proportion of patients, painful or thermal stimuli applied within analgesic parts of the body arouse a sensation, which is felt not at the place actually stimulated but in a normally innervated part of the body [l-3]. The mechanism underlying this reference of the sensation was considered to be due to the conduction of the sensation via chains of short neurons in the spinal cord [1,3]. With this hypothesis Nathan [l] tried to account for all the features of the spread and pattern of reference of sensation; spread across to the analogous place on the opposite side
91
of the body, spread cranially or caudally, lack of correct local signs, the fact that the reference is always to the region adequately innervated by spinothalamic tract, and the fact that the harder the stimulation the further the sensation is referred. The conduction of the sensation via chains of short neurons was considered to be associated with a state of hyperexcitability of the central nervous system, which was assumed to be induced by the division of large numbers of nerves or division of an algesic tract inside the central nervous system. After cordotomy, usually for the treatment of intractable cancer pain, sometimes a new pain occurs on the opposite side of the body without applying any painful stimuli to the analgesic part of the body [1,2,4]. Nathan [1,2] ascribed this to the reference of the original pain sensation. Although this assumption seems reasonable nobody has confirmed it. In our case after cordotomy a new pain occurred in the analogous part of the body on the opposite side, and at the same time reference of the sensation from analgesic part of the body to the opposite side was observed. As soon as the nerves conveying cancer pain to the spinal cord were blocked by intrathecal phenol injection, the new pain on the left side of chest was abolished, and at the same time the reference of the sensation from the area anesthetized by phenol block disappeared, though it remained unchanged in other analgesic parts of cordotomy. This confirmed that the new pain was a reference from the original right chest pain. So far we have performed 33 unilateral cordotomies on patients suffering from cancer pain restricted to one side of the body. In 21 cases, a new pain appeared on the opposite side of the body within 1 week after cordotomy. In 4 of the 21 cases, the new pain was considered to be caused by reference of the original pain, because no organic changes were found on the side of new pain, and the reference of sensation from analgesic to opposite side of the body was observed. (The reported case here is one of these.) In 8 other cases reference of the original pain was suspected as a cause though the reference of sensation could not be induced. In the remaining 9 cases organic changes which could cause pain were found on the side of new pain, though it was not determinable if they actually caused the new pains. We concluded that the reference of sensation is one definite cause of the phenomenon in which a new pain occurs on the opposite side to the original cancer pain after a cordotomy, as is substantiated by our report. References 1 Nathan, P.W., Reference of sensation at the spinal level, J. Neurol. Neurosurg. Psychiat., 19 (1956) 88-100. 2 Nathan, P.W., Results of antero-lateral cordotomy for pain in cancer, J. Neurol. Neurosurg. Psychiat., 26 (1963) 353-362. 3 Ray, B.S. and Wolff, H.G., Studies on pain ‘spread of pain;’ evidence on site of spread within the neuraxis of effects of painful stimulation, Arch. Neurol. Psychiat. (Chic.), 53 (1945) 257-261. 4 Ventafridda, V., De Conno, F. and Fochi, C., Cervical percutaneous cordotomy. In: J.J. Bonica, V. Ventafridda and C.A. Pagni (Eds.), Advances in Pain Research and Therapy, Vol. 4, Raven Press, New York, 1982, pp. 185-198. 5 White, J.C. and Sweet, W.H., Spinothalamic tractotomy: complications, technique and review of new alternative procedures. In: J.C. White and W.H. Sweet (Eds.), Pain and the Neurosurgeon: a Forty-Year Experience, Thomas, Springfield, IL, 1969, pp. 748-749.