The surgical procedure called Selective Dorsal Rhizotomy (SDR) is to try and give Maddi some quality of life and to hopefully keep her walking for a while longer. SDR is not available in the UK for Maddis disease, but the world leading specialist Dr Park at St Louis Childrens Hospital has already treated other patients with Hereditary Spastic Paraplegia successfully and so many CP children with some fantastic results, he has suggested this would be a good option for Maddi.