Praying for your little guy, Cinda! That must be heart-breaking to see him suffer. This may be a long shot but had a friend suffer through kidney stones so that's been on my mind. Understand they're very painful. Didn't realize that might be possible for Mini Schnauzers until I read the attached websites below. You said the vet gave him a complete physical which probably included urinalyses and x-rays, but you're now awaiting results from the spinal analysis. Let us know how things go.
Common Health Issues:
The miniature schnauzer as a breed is not plagued with many prevalent health issues. However there are a handful of rare disease to look out for. "Juvenile renal disease, also known as JRD, occurs in a number of dog breeds, including the miniature schnauzer," according to the AMSC Health Committee. Other possible health risks for this breed are retinal dysplasia, hyperlipidemia and bladder stones.
Please keep us informed, Cinda...ysiC, Sandra Jean