The present invention relates to a system for guiding a surgical tool (200) held by a user to at least one target axis (T) defined in a patient's spinal coordinate system, the system comprising: (i) a robotic device ( 300), a base (301), a guide device (303) configured to constrain the tool to a guide shaft (G), and-movable with respect to the base (301), A small electric actuation unit (304) connected to the device (303) for adjusting the position and orientation of the guide device with respect to the target axis； and-connected to the base (301), the partial electric drive unit between the guide device and the spine. A support unit (305) comprising at least one element designed to contact the spine or an area of the patient's body adjacent the spine to provide a mechanical link. Device (300), (ii) a passive articulating lockable holding arm (400) supporting the base (301) of the robotic device, and (iii) the posture of the guide axis relative to the patient's spine coordinate system in real time. A tracking unit (500) configured to determine, and (iv) a control unit, (a) determining the orientation of the guide axis with respect to the target axis, and (b) the workspace of the robotic device for the determined orientation. And (c) calculating at least one indicator representing the ability of the actuating unit to align the guide axis with the target axis based on the calculated workspace and the attitude of the guide device. And (v) a user interface connected to the control unit and configured to display a representation of the guide axis (G) with respect to the target axis (T). And (600), comprising a control unit controls the operation unit, and a guide shaft is further configured to align with the target axis.本発明は、患者の脊椎の座標系で定義された少なくとも１つのターゲット軸（Ｔ）に対してユーザが保持する外科手術ツール（２００）を案内するシステムに関し、システムは、 （ｉ）ロボット装置（３００）であって、 －ベース（３０１）と、 －ツールを案内軸（Ｇ）に拘束するように構成された案内装置（３０３）と、 －ベース（３０１）に対して移動可能であり、案内装置（３０３）に連結されてターゲット軸に対する案内装置の位置と向きを調整する小型の電動作動ユニット（３０４）と、 －ベー
