A surgical system comprising: an electrical stimulation generator; at least one sensor disposed at a working end of a surgical instrument; and a controller coupled to the at least one sensor (120, 122), the controller being configured to: obtain data from the at least one sensor over time in response to a stimulation applied by the electrical stimulation generator, analyze the data obtained from the at least one sensor (120, 122) over time to generate sensor data analysis results; apply a signal processing method and/or a pattern matching to the sensor data analysis results; and indicate if a tissue or artifact is present within a region proximate to the working end of the surgical instrument based on the signal processing method or pattern matching, characterized in that the at least one sensor comprises at least one light emitter and at least one light sensor, the at least one light emitter and the at least one light sensor disposed at the working end of the surgical instrument; and the controller comprises a splitter to separate a pulsatile component from a non-pulsatile component from a signal from the at least one light sensor and an analyzer to analyze the pulsatile and/or non-pulsatile component to generate the sensor data analysis results and apply the signal processing method and/or pattern matching to the sensor data analysis results. an electrical stimulation generator; at least one sensor disposed at a working end of a surgical instrument; and a controller coupled to the at least one sensor (120, 122), the controller being configured to: obtain data from the at least one sensor over time in response to a stimulation applied by the electrical stimulation generator, analyze the data obtained from the at least one sensor (120, 122) over time to generate sensor data analysis results; apply a signal processing method and/or a pattern matching to the sensor data analysis results; and indicate if a tissue or artifact is present within a region proximate to the working end of the surgical instrument based on the signal processing method or pattern matching, obtain data from the at least one sensor over time in response to a stimulation applied by the electrical stimulation generator, analyze the data obtained from the at least one sensor (120, 122) over time to generate sensor data analysis results; apply a signal processing method and/or a pattern matching to the sensor data analysis results; and indicate if a tissue or artifact is present within a region proximate to the working end of the surgical instrument based on the signal processing method or pattern matching, characterized in that the at least one sensor comprises at least one light emitter and at least one light sensor, the at least one light emitter and the at least one light sensor disposed at the working end of the surgical instrument; and the controller comprises a splitter to separate a pulsatile component from a non-pulsatile component from a signal from the at least one light sensor and an analyzer to analyze the pulsatile and/or non-pulsatile component to generate the sensor data analysis results and apply the signal processing method and/or pattern matching to the sensor data analysis results.