Hi Susan,
In my book of homeopathic remedies for cats by George Macleod it sais
'
If the infection of an open wound proceeds to a more chronic stage leading to tissue being under-run with the establishment of sinuses and fistula (a common occurrence in the cat) SILICEA should prove useful. Potency of 200c should be considered 3x weekly for 4 weeks'
I hope this will help you. Also have a look on this side :
http://www.shirleys-wellness-cafe.com/holisticguide.htm
There is always something interesting to find here.
Mirjam