These parameters increased ( L@-L@ ) : mean distance ( transverse plane ) between the starting point and middle of the spinous process , @ ( @ cm ) , @ ( @ cm ) , and @ ( @ cm ) , respectively ; mean screw sagittal angle with respect to the posterior skin , @ ( @ ) , @ ( @ ) , and @ ( @ ) , respectively ; and mean distance for guide wire entry , @ ( @ cm ) , @ ( @ cm ) , and @ ( @ cm ) , respectively .