(Newbie) String within a string

I'm trying to grab a string from within a string based on a matching word or phrase. Example... $string = "This is a string I need to grab the middle out of" $query_word = "need" I need to get x amount of characters either side of $query_word, so the result string would be like... "string I need to grab the" And I need the result string to be full words, not like..."ing I need to grab th" I've half managed to do it using strpos and substr but the code is really messy and I'm getting half-formed words back. Anyone got any suggestion on how to accomplish this? Thanks very much in advance. Steve