Posted: 01/04/2015 at 16:23
In my experience - which includes clubmates' anecdotes plus personal experience of getting ITBS on my right knee and making all the classic mistakes to prolong recovery, followed by ITBS on my left knee the following year but recovering much more quickly, I found that if you stop at the very first sign of ITBS pain and rest from running for a week, then you can get away with resuming normal training if pain free after that rest. However if you try running through ITBS pain at all, then you need to rest for several weeks until it's pain free, then rest for a couple more weeks after that. 6 weeks seems to be typical in this scenario.
Attempts to resume running any sooner usually result in the cycle of repeated short rests and aborted painful returns that end up costing more time than if having just stopped at the first sign of ITBS.
So I would say defer til next year if you can, as it does not seem worth wasting a VLM place if you know you cannot do yourself justice. Then work on fixing the root cause of the ITBS, whether that was glutes, hips, TFL, upping mileage too quickly etc, and get stronger for the comeback.
But if you're desperate/committed to doing VLM this year in particular for whatever reason, you could probably get round, but be mentally prepared for it to be painful, disappointing and/or slow. Good luck in whatever you choose to do.
If you do go ahead with it this year, I personally would not recommend an 18 miler 2 weeks beforehand; an experienced higher mileage runner might be ok with that, but if that's your longest run it sounds like an exercise in boosting confidence but to the detriment of your condition for race day.