The clinical descriptions of cordotomy played a major role in elucidating the function and the anatomy of the human spinothalamic tract (STT) (Chapter 1). There are a number of other examples of surgical interventions which have informed our understanding of the pain system. In particular, the pain-related role of the cingulate gyrus is suggested by imaging studies and by the effect of cingulotomy on experimental pain (Rainville et al., 1997; Gildenberg, 2004). Similarly the role of the motor cortex in these systems has suggested the effects of stimulation on activity throughout the pain system (Brown and Barbaro, 2003; Brown, 2004; Peyron et al., 2007). The purpose of this chapter is to examine these surgical interventions in terms of the anatomy and function of structures involved in these interventions. The inclusion of procedures in this chapter is arbitrary and many other such procedures which might have been included have been excluded.

Cordotomy and myelotomy

Percutaneous cordotomy produces relief of pain by interrupting the transmission of signals in the STT from below the level of intervention (Tasker, 1988; Tasker, 2004). The anterolateral quadrant of the spinal cord has long been recognized as the location of the STT (Chapter 1). Recent findings indicate that the dorsal column system also has an important role in visceral nociception (Nauta et al., 1997; Willis et al., 1999). The STT terminates in the primate thalamus, brainstem and other structures such as the hypothalamus and amygdala whereas the dorsal column system terminates in the dorsal column nuclei (Newman et al., 1996).