They're reverted shoots, it does happen. Trace them back to their point of origin and cut them off there.

We have a Corkscrew hazel and I remove straight branches from it every year...

Thank you both for your speedy replies which I found to be most helpful.

You could try propagating the straight shoots as hazel makes good plant supports in place of dried out bamboo.

Um… Urbanite I'm sure you didn't mean to describe Bamboo as dried out :)

;-))) - actually, it ain't that far from the truth these days, MG...

Moon grower gets funnier.

lol Bamboo!