When are D waves typically recorded?

D waves, or descending waves, are typically recorded in the context of intraoperative monitoring during procedures involving the spinal cord, particularly in surgeries that encounter the spinal cord directly, such as those performed for intramedullary spinal cord tumors. This is due to their role in providing vital information regarding motor pathway integrity.

In surgeries involving intramedullary spinal cord tumors, monitoring D waves helps surgeons assess the real-time function of motor tracts and allows for the early detection of potential neural compromise. This is crucial since the proximity of surgical intervention to vital neural pathways can result in unintended damage if not carefully managed.

While D waves can have a role in monitoring during various surgical procedures, they are particularly significant for the specific context of surgeries that directly interact with these delicate structures. Their presence indicates functioning descending motor pathways, which is not necessarily monitored in all surgical settings or minor surgeries. Therefore, the correct context for the recording of D waves is indeed during procedures involving intramedullary spinal cord tumors.