The drugs in the analgesic pump include butorphanol, hydromorphone, tramadol, and other medications.

The Visual Analog Scale (VAS) is primarily used, where 1 represents no pain (best outcome) and 10 represents the worst pain (worst outcome); other scales may be used if necessary.

Postoperative functional recovery status mainly includes: the time of first passage of gas, the time of first ambulation, the time of first catheter removal, and the recovery of limb muscle strength. The passage of gas, ambulation, and catheter removal times are self-reported by the patients, recording the days after surgery when the events occurred. The recovery of limb muscle strength is classified into six levels, ranging from 0 to 5, where 0 indicates no detectable muscle contraction (worst outcome) and 5 indicates normal muscle strength (best outcome).

The sedation score uses a scale from -5 to +4, where -5 is defined as coma (one of the worst outcomes); -4 is defined as severe sedation (responds to physical stimulation); -3 is moderate sedation (no response to auditory stimulation); -2 is mild sedation (unable to maintain alertness for more than 10 seconds); -1 is drowsiness (not fully awake but can stay awake for more than 10 seconds); 0 is the awake natural state (best outcome); +1 is restlessness and anxiety (anxious and tense, but only slight body movement); +2 is agitation and anxiety (intense body movement); +3 is very agitated (trying to remove body tubes); +4 is aggressive (violent behavior) (one of the worst outcomes).

Patient overall satisfaction is self-reported, with a score range from 0 to 100, where 0 represents the least satisfied (worst outcome) and 100 represents the most satisfied (best outcome).