The patients in Group C (placebo control group) received normal saline intravenous injection

Patients will be assessed for pain using a visual analogue pain scale (VAS). It is usually a horizontal line, 100 mm in length, anchored by word descriptors at each end; left side end which represents 0 is 'No pain', right side end with 100 is 'Very severe pain'. The patient marks on the line the point that they feel represents their perception of their current state. The VAS score is determined by measuring in millimeters from the left hand end of the line to the point that the patient marks.

To check the severity of pain VAS will be measured at post op 12 hour.

Patients will be assessed for pain using a visual analogue pain scale (VAS). It is usually a horizontal line, 100 mm in length, anchored by word descriptors at each end; left side end which represents 0 is 'No pain', right side end with 100 is 'Very severe pain'. The patient marks on the line the point that they feel represents their perception of their current state. The VAS score is determined by measuring in millimeters from the left hand end of the line to the point that the patient marks.

To check the severity of pain VAS will be measured at post op 48 hour.

The patients will be taught to push the button of the PCA system, which delivered a bolus of drug, each time pain occurred. In the case of persistent pain greater than a visual analogue scale (VAS) pain score of 30 mm, an additional 50 μg of fentanyl will be injected intra-venously by nursing staff until the pain was relieved to a level less than a VAS pain score of 30 mm. And sum of delivery from PCA system and additional opioid fom immediately after operation to post op 4hour will be measured.

The patients will be taught to push the button of the PCA system, which delivered a bolus of drug, each time pain occurred. In the case of persistent pain greater than a visual analogue scale (VAS) pain score of 30 mm, an additional 50 μg of fentanyl will be injected intra-venously by nursing staff until the pain was relieved to a level less than a VAS pain score of 30 mm. And sum of delivery from PCA system and additional opioid from 12 hour to post op 24 hour will be measured.

The patients will be taught to push the button of the PCA system, which delivered a bolus of drug, each time pain occurred. In the case of persistent pain greater than a visual analogue scale (VAS) pain score of 30 mm, an additional 50 μg of fentanyl will be injected intra-venously by nursing staff until the pain was relieved to a level less than a VAS pain score of 30 mm. And sum of delivery from PCA system and additional opioid from post op 4hour to post op 12 hour will be measured.

The patients will be taught to push the button of the PCA system, which delivered a bolus of drug, each time pain occurred. In the case of persistent pain greater than a visual analogue scale (VAS) pain score of 30 mm, an additional 50 μg of fentanyl will be injected intra-venously by nursing staff until the pain was relieved to a level less than a VAS pain score of 30 mm. And sum of delivery from PCA system and additional opioid from post op 24 hour to post op 48 hour will be measured

The patients will be taught to push the button of the PCA system, which delivered a bolus of drug, each time pain occurred. And total frequency of patient to push the button of the PCA machine (FPB) fom immediately after operation to post op 4 hour will be measured.

The patients will be taught to push the button of the PCA system, which delivered a bolus of drug, each time pain occurred. And frequency of patient to push the button of the PCA machine (FPB) from post op 4 hour to post op 12 hour will be measured.

The patients will be taught to push the button of the PCA system, which delivered a bolus of drug, each time pain occurred. And frequency of patient to push the button of the PCA machine (FPB) fom post op 12 hour to post op 24 hour will be measured.

The patients will be taught to push the button of the PCA system, which delivered a bolus of drug, each time pain occurred. And frequency of patient to push the button of the PCA machine (FPB) fom post op 24 hour to post op 48 hour will be measured.