Brief Answer:
No worries, side effect you mentioned from literature is rare
Detailed Answer:
Thank you for asking
I read your question and i understand your concern. Levaquin is a fluoroquinolone antibiotic and its side effect of weaker tendons is very rare and that too in young age of less than 18 years use and not in your case. So no worries. So you can use this antibiotic for chronic sinusitis and get precautionary measures to prevent future exposure like dust and pollen exposure to be reduced. Also in carpenter hood, use some mask to avoid that wooden dust . Also if your doctor as ruled out any anatmoical cause for chronic sinusitis like deviated nasal septum or any other surgically correctable cause then supportive care is all you need. Use of antihistamines like desloratadine on and off for supportive care will help.
I hope it helps. Take good care of yourself and dont forget to close the discussion please.
Regards
Khan