Staff at Yorkshire Wildlife Park have said they "breathed a huge sigh of relief" when their 12-year-old tiger Vladimir woke up unscathed from a risky medical procedure.
Kim Wilkins, carnivore team leader, said the Amur tiger, known as Vlad, came round from the general anaesthetic, following an X-ray on his spine, looking "annoyed, but alert".
She described the procedure as a "heart-in-the-throat" situation, which could cause the tiger to hallucinate or stop breathing, but is essential to check any changes to his back condition.
Around two years ago, staff at the park, in Doncaster, South Yorkshire, noticed a curve in Vlad's spine, causing him discomfort and an "odd" gait when he walked.
He was prescribed painkillers, which helped his movement, and now his keepers observe his mobility and behaviour every day and he has weekly observations by vets.
Once a year, Vlad has to undergo an X-ray on his back and hips to check his condition has not progressed, and blood tests to ensure his painkillers are not affecting his liver and kidney function.
Ms Wilkins said initial indications from Wednesday's procedure are that there was no major change to Vlad's condition and he is recovering well from the anaesthetic - known as a "knock-down".
She continued: "It can be really dodgy but they have to make that welfare call that we absolutely need to know what's happening with his spine, so we know that he's not in compromised welfare. But knock-downs don't come without risk."
Ms Wilkins said they do not know what caused Vlad's condition but his cubs are being observed in case they develop the same issues as they get older.
Yorkshire Wildlife Park has three Amur tigers - male Vlad, who has been at the park for around 10 years, and two females, Sayan and Tschuna.
Ms Wilkins said: "Vlad is an absolutely lovely boy, he's very nice to his ladies and he's a proud grandad now.
"He fathered cubs here at the park about six years ago and they've gone on to have babies, so he's actually a grandad, believe it or not.
"He's fabulous and he's a definite favourite with the team, a beautiful, beautiful boy."
Ms Wilkins said they will give Vlad a treat once the effects of the anaesthetic have worn off.
She said: "We'll leave him to this evening, let his stomach rest and then we'll give him a nice, big feed tomorrow.
"He might get a horse leg if he's lucky."