hi, thank-you for providing the brief history. As your mother has the previous history of arthritis and disc pathology, due to the fall the disc might have moved and giving compress to the nerve roots again. Taking a recent MRI will help to understand the causes better. Also, a complete bed rest is advised along with physical therapy like therapeutic ultrasound therapy and TENS therapy to reduce inflammation and pain. Later stages as the condition improves physical therapy exercises should be initiated to make the core stronger to avoid recurrence of the symptoms. In my clinical practice most cases with old history of disc pathology has similar issues and with proper attention they respond well. Regards Jay Indravadan Patel