ABSTRACT
Neurological deficit is the most feared complication of spine surgery. It can occur presurgically during transfer of the patient to the operating room table, from neck extension for airway management during intubation, during patient positioning for adequate operative exposure, or as a result of surgically induced injury. To be sure, appropriate preoperative preparation, careful surgical planning, precise surgical execution, and constant surgical vigilance can minimize risk for neurological complication. An increasingly important means of injury prevention is continuous intraoperative neurophysiological monitoring (IONM) of spinal cord and spinal nerve root function (1-3). As with any other type of medical test, interpretation of IONM data requires complex clinical decision making, which takes place in the presence of some uncertainty. Decision making is the process of selecting a specific course of action from among a set of alternatives. It begins at the information-gathering stage (e.g., recording a neurophysiological response) and proceeds through the establishment of likelihood estimation (e.g., deciding if the response has changed significantly) until the final act of choosing an action (e.g., alerting the surgeon of evolving spinal cord injury). This chapter discusses the interpretation of IONM data in the context of signal-detection theory (SDT). The goal of this chapter is to reduce the complications associated with misinterpretation of IONM data through careful examination of the intraoperative decision-making process as defined by SDT.
