It ranges from genuinely elective to genuinely hours critical, and one finding separates them: deep pain sensation. A dog that still feels a firm toe pinch has time for proper assessment and considered decisions, usually days. A dog that has lost deep pain is in the tightest window in veterinary neurology, where the odds of walking again fall meaningfully with every several hours of delay.
In between sits the dog that cannot walk but still feels: surgical, and prompt, but not a reason to panic drive through the night past a competent referral centre toward a distant one. Outcomes for these dogs stay good with surgery inside a day or two.
Practical advice for the worried owner: ask the assessing vet directly, does my dog have deep pain, and write the answer down with the time. If the status ever changes, the clock has changed, and the referral centre should hear about it immediately.
Send what your vet said and quoted. A veterinary surgeon reads it and comes back to you with what they can do and what it would cost, before you pay anything. A written second opinion is from $250.
Send the case, hear back from a surgeon with what they can do and what it costs, and only pay if you go ahead.