Thermal Protection Strategies and Neuromonitoring during Ablation

Abstract

Advanced interventional pain management approaches seek to lesion neural targets to achieve desirable analgesia; however, equally important is preservation of motor and sensory function for regional bystander nerves. The topic of neuroprotection is also relevant for thermal ablation of metastatic bone tumors in the vicinity of neural structures. This report aims to provide an IR-directed framework of thermoprotective techniques available during thermal ablation.

Keywords: analgesia; cancer pain; interventional radiology; pain management; thermal ablation.

Fig. 1

Normal and abnormal somatosensory evoked potential (SEP) waveforms. ( a ) Normal SEP waveform elicited after left tibial nerve stimulation. Each column shows a typical waveform; the arrow points to the waveform recorded from cortical sensory areas. The arrowhead points to the response recorded from the tibial nerve. Time is listed on the right-most column. Notice that there is no significant change in the waveforms as time progresses. ( b ) SEP waveform elicited after left tibial nerve stimulation. Notice that the waveform in the left-most column marked with an arrow (recorded from the cortical sensory area) decreases in amplitude over time, suggesting potential compromise to the relevant dorsal column pathway. Time is listed on the right-most column.

Fig. 2

Normal and abnormal motor evoked potential (MEP) waveforms. ( a ) MEP obtained after stimulation of the scalp and recorded from several muscle groups in the left upper and lower extremities. Each column shows an MEP response from a single muscle group. Time is listed on the right-most column. Notice that there are no significant changes in the waveforms in any of the columns as time progresses. (Names of muscle groups noted in upper left hand of the columns.) ( b ) MEP obtained after stimulation of the scalp and recorded from several muscle groups in the right upper and lower extremities. Each column shows an MEP response from a single muscle group. Time is listed on the right-most column. Notice a gradual decrease in the MEP amplitude from the right foot, marked with an arrow. The loss of MEP amplitude suggests possible compromise of the motor fibers supplying the relevant muscle group. (Names of muscle groups noted in upper left hand of the columns.)