If the urine did not soak very deep into the wood, you could use a sander and sand the stained spots until the stain is gone. The stain should be obviously darker than other areas. When you are finished sanding, be certain to vacuum very very well. Then spread a large amount of Arm and Hammer baking soda on all of the areas and around the immediate areas. I'm sure that you know to replace your padding and clean and or replace your carpet where the stains are? I'm not sure if this will work because I have not personally tried it. I've been told one can take a black light into a room and every place a cat has urinated will show. If this works, please let me know!