Final answer:
Opioids are added to spinal anesthesia to enhance pain relief during and after surgery.
Step-by-step explanation:
Opioids are added to spinal anesthesia to enhance the pain-relieving effects of the anesthesia. Spinal anesthesia blocks pain signals in a specific area of the body, but opioids can further reduce pain and provide longer-lasting relief. By combining opioids with spinal anesthesia, healthcare providers can achieve better pain control during and after surgery.