The six-year-old lhasa apso is recovering after undergoing a two-hour emergency operation to repair deep bite wounds following the mauling.
Sam also lost two teeth in the attack in Newchapel.
Now owner Lynda Dawson is warning other dog owners to be on their guard.
The mother-of-two, a company director, of Jasmine Crescent, Newchapel, said: "My daughter Hollie was walking Sam down an alley next to our house and came across a rottweiler.
"It picked up Sam, violently shaking him like a rag doll.
"The rottweiler then dropped Sam, which knocked two of his teeth loose.
"It had a lead on and was with an old man, but he was not holding on to the lead.
"He was nearby talking to another elderly man and the attack only stopped when that second man hit the rottweiler with his walking stick.
"Sam has a lot of bruising, a four-inch gash to his side, his genitals are badly bitten and the two teeth knocked loose in the attack had to be removed.
"He is a mess and the vet doesn't know how long it will take him to recover."
The family has already forked out £1,500 in vet bills, but expect the figure to continue to rise as Sam still needs aftercare appointments every other day and may yet have to undergo a second operation.
Mrs Dawson said Sam is insured but is hoping the rottweiler's owner will foot the bill.
She added: "The rottweiler was out of control.
"It's difficult to see your pet so traumatised. He's not eating much, we're feeding him by hand and he may never be back to his old character again.
"I can't describe how difficult it is for our family. And it could happen again. That rottweiler is regularly in the area and I believe it has caused difficulties for other dog owners.
"It could be a child next time. I don't want it put down, just muzzled and walked by someone who can control it properly."
Congleton High School pupil Hollie was walking Sam on a lead when the attack happened a week ago.
The 16-year-old, said: "It was really upsetting. I used to walk Sam twice a day, but now I feel scared to take him out on my own because it could happen again.
"It's really distressing because he's yelping all the time because of the pain but we cannot pick him up and give him a cuddle because his injuries need to heal."
The police and dog warden have been informed about the incident.
Craig Brown, dog warden at Newcastle Borough Council, confirmed the rottweiler's owner had been given advice on how to keep it under control by using a muzzle, head collar, body harness and a better lead.
He added: "He was fully co-operative and agreed to the measures.
"I gave Mrs Dawson advice about pet insurance and posted a witness statement for her to complete, which we will submit to the police.
"The borough council doesn't have powers to enforce advice, however it can enforce control orders issued by the courts."
(The Sentinel - March 27, 2012)
