I had this same problem, in the future plan for this in advance. In the veg stage, when your plant is appx. 12-24" tall, top it. Carefully spread the lower branches & then loosely tie them off to some bamboo sticks. You can repeat this process a few times as the plant grows. I usually end up with about 12-18 sticks around a 5-6 foot diameter plant, much wider than it is tall.
My goal is to keep my plants around 4 to 4 1/2 feet tall come harvest. When flower stage arrives remember your plants will still grow about a foot appx. You won't get a monster yield, probably 4-8 oz., but more importantly, you probably won't get caught or ripped.
Also, if your growing in a pot, check out smart pots.
Good Luck