I am so sorry to hear Toby is having problems.
Really have no advice-just want you to know I care.
Did a Google and came up with these: http://www.google.com/search?q=Cause...e7&rlz=1I7SUNA
Results 1 - 10 of about 110,000 for Causes of Weakness in Dog's Back Legs. (0.24 seconds)
Search ResultsMotion and Motor ProblemsMuscle mass on back legs and over her rear end seems to be diminishing (visual ... He suddenly experienced weakness in hind legs,difficulty raising himself on ... dog, they will sometimes cause significant weakness in the rear limbs. ... www.vetinfo.com
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Ask the Veterinarian: Sudden Paralysis of Left Rear Leg, energetic ...Could it be a Disk or back problem that could also be causing this? and ... Another condition of small dogs, especially young ones, that will cause ... the dogs initially develop a weakness in the hind limbs that can look like lameness. ...
en.allexperts.com › Ask the Veterinarian - Cached
Google Answers: Dog with hind leg problemsDec 9, 2005 ... Q: Dog with hind leg problems ( Answered 4 out of 5 stars ..... Taking the supplements with aspirin may cause problems in ... DM presents itself with waxing and waning of the following symptoms: *hindquarter weakness, ...
answers.google.com/answers/threadview/id/603620.html - Cached
WikiAnswers - What disease in dogs cause immobility in hind legsHind legs give out in dogs? Nerve damage in dogs hind legs? What are analogies for immobility? What causes weakness in hind legs of dogs? ...
wiki.answers.com/.../What_disease_in_dogs_cause_immobility_in_hind_legs - Cached
Back Pain, Leg Weakness Signs of Nerve-Related SyndromeThese tests are often necessary, since there are several other conditions which cause back pain and hind leg weakness in dogs, and these causes need to be ... www.terrificpets.com/articles/10267965.asp