If your main is damaged terminating it isn't always the best option. If your vine has a split that runs the length of the vine simply clean up and dry off the split area, take some twist ties and close up the split. Don't put the ties very tight. Just enough to close the split. After 3-5 days remove the ties and your plant should be healed.
Sometimes just burying the vine will work fine for a horizontal cracks. This is especially true if you already have your pumpkin growing and there isn't any other options. Along with burying the vine put some compost tea on the damaged area to help to protect it.