1. An analysis method for a surgical operation via endoscopy at an operative site in a volume located inside the body of an animal, said method comprising: detecting at least one instrument present in the operative site, detecting at least one portion of an organ in the vicinity of the detected instrument, determining the positioning of the detected instrument relative to the detected organ, so that the detected instrument, the detected portion of organ, and their relative positioning form parameters defining a detected surgical step, selecting in a database a conceptual surgical step corresponding to the detected surgical step from the detected instrument, the detected portion of organ, and their relative positioning, comparing the parameters of the detected surgical step with the parameters defining the selected conceptual surgical step to determine the differences between these parameters, providing information on the quality of the detected surgical step on the basis of determined differences.