This is not only important from the standpoint of patient comfort. It also reduces the incidence of many of the complications of surgery, since it is important for the patient to be able to deep breath and cough to avoid the development of collapse of the lung and pneumonia.
Another effective system of pain control is called epidural anesthesia, and involves placement of a catheter through a needle into the space surrounding the spinal cord and infusing narcotics and local anesthetics after surgery.
Intermittent injections of narcotics on request (PRN) of the patient is the traditional method of post-operative pain control, but does not produce acceptable pain relief.