RESUMEN
During an 18-month period 11 patients were seen at the Toronto Western Hospital Pain Clinic 4 months to 5 years after internal mammary artery (IMA) bypass with a specific cluster of chest wall symptoms and signs confined to the site of IMA graft harvesting. Sympathetic ganglia blocks produced dramatic but temporary relief of symptoms in two of the most severely affected patients. In two other patients seen quite early after surgery, use of transcutaneous electrical stimulation produced considerable and permanent decrease of symptoms within 3 weeks. Such a chronic pain syndrome has not been previously reported in the literature. We postulate that IMA bypass surgery may be associated with a specific pain syndrome. This syndrome may arise from injury to the anterior branches of the intercostal nerves at the site of graft harvesting. Possible neurophysiologic mechanisms are discussed.
Asunto(s)
Dolor en el Pecho/etiología , Puente de Arteria Coronaria/efectos adversos , Arterias Mamarias/trasplante , Dolor Postoperatorio/etiología , Arterias Torácicas/trasplante , Anciano , Bloqueo Nervioso Autónomo , Dolor en el Pecho/fisiopatología , Dolor en el Pecho/terapia , Femenino , Humanos , Nervios Intercostales/lesiones , Masculino , Persona de Mediana Edad , Dolor Postoperatorio/fisiopatología , Dolor Postoperatorio/terapia , Estudios Retrospectivos , Sistema Nervioso Simpático/fisiopatología , Síndrome , Estimulación Eléctrica Transcutánea del NervioRESUMEN
Several authors have shown that dorsal column stimulation (DCS) modifies appreciation of pain. We studied the effects of DCS on the somatosensory evoked response (SER) in six subjects. Somatosensory evoked responses to stimulation of the tibial nerve and effects of varying frequencies and intensities of DCS on SER components were recorded. During DCS there was attenuation of late SER components with little effect on early components. Stimulus intensities greater than necessary to relieve pain suppressed all SER components. Our findings suggest that the minimal effective DCS variables to relieve pain are those that produce selective suppression of late SER components.