C.06 Somatotopic organization of the human spinothalamic tract: CT-guided mapping in awake patients undergoing cordotomy

Abstract

Background: After correlating in vivo macrostimulation-induced pain or temperature sensation during percutaneous cervical cordotomy with simultaneous CT imaging of the electrode tip location, we present a modern description of the somatotopy of the human cervical spinothalamic tract Methods: Twenty patients with medically refractory, unilateral, nociceptive pain due to malignancy received contralateral cervical percutaneous cordotomy. In a post-hoc analysis of the data, each individual’s cervical spinal cord was measured from the CT image using PACS software. The location of the electrode tip during each stimulation-induced response was then superimposed on a diagram of their cord Results: The lower limb responses were found more superficial and posterior to those of the upper limb. Interestingly, the region for upper limb responses surrounded that for lower limb primarily anteriorly and medially (deep) but also posteriorly Conclusions: This work simultaneously combined awake physiologic localization of fibers within the human -spinothalamic tract (STT) with neuroimaging documenting their precise anatomical localization within the spinal cord. The resultant map of the STT demonstrates, for the first time, that fibers from the lower limb are located superficially and posteriorly within the anterolateral spinal cord with the fibers from the upper limb surrounding them primarily deep and anteriorly but also posteriorly