I have actually had buckleys success treating culture positive anal sacculitis with systemic antimicrobials – the more you give, the more resistant the bacteria are in there – but they are always in there…
The best medical success I have had is flushing weekly for 4-6 weeks and instilling a topical antibiotic + cortisone into the gland. I just thread a 22g catheter (without stylet!) into the duct, and attach a saline syringe and flush. My favourite ointment to instil is Panalog, but if you can’t get that either chloramphenicol + a cortisone-containing ophthalmalogic preparation seems to do the trick. I’ve also sucessfully used manuka honey a few times, but you have to use a big catheter because it’s so thick!
Regarding when to go to surgery: If the anal sac feels large and flaccid after a couple of flushes, I usually take them out. If they are full and feel like they have good tone, I tend to persist with medical managment.