To be honest, MySQL I'm not that well know (especially in terms of data types), so I'll try to advise based on experience with PostgreSQL
1) Change the data type of the path. Now, if I understand correctly, is a string — try something binary (similar to PostgreSQL bytea) or Nicodemou (that is, if, for example, by changing the numbers on signs, the code which corresponds to the figure to choose the correct separator, and the entire base while hanging in Unicode all will be sorted correctly). True, it can get some problems using nekrasivyh or illegal characters (in PostgreSQL get out) or with character encoding (Cyrillic can make some confusion and have to use shift).
2) to See if it will work to implement something like type stored PostgreSQL LTree (don't know, does it happen in MySQL)
3) Write your own sorting function (better on C) (don't know, does it happen in MySQL)