Systems and methods for automatically determining pedicle screw trajectories for surgery may be provided. A scan of a spine may be received, and positions of one or more vertebra and one or more components of the one or more vertebra in the scan may be identified. Next, a screw trajectory planning algorithm may determine an initial screw trajectory plan using the positions of the one or more vertebra and the one or more components. The screw trajectory planning algorithm may then determine a revised screw trajectory plan by revising the initial screw trajectory plan according to weighted factors.