If you are unsure about this vet's opinion on the topic you can always seek another opinion.
http://www.marvistavet.com/html/anal_sacs.html
I would be tempted to see if antibiotics and maybe a diet change would resolve this. You can always opt for surgery but you can't undo surgery.
Some people find that the anal sac problem goes away when they stop feeding certain food ingredients found in the usual commercial dog foods.
You might find going to a food with no corn, wheat, soy, or beef in it will help. California Natural, Wellness fish,duck, rabbit, or venison, or one of the other higher quality dog foods might work for you to help with this.
If it continues to be a problem you can always opt for surgery. If you do I'd go with a board certified surgeon rather than your regular vet.
Hope this helps you!
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