A decrease in pH occurs immediately after incision and is sustained for at least 4 days. During the period of decreased tissue pH, pain behaviors are evident. When the tissue pH returns to normal, pain behaviors are diminished. The decreased pH is localized at the incision site and not to areas surrounding the incision. Decreased pH likely contributes to nociceptor sensitization and pain related behaviors after incision. The magnitude of the pH change varies among tissues. An increase in hind paw skin temperature does not play a role in these pain-related behaviors.

Although several studies postulated that mouse strain influences pain models, the authors' data indicate that such influence on incisional pain is negligible. This suggests that studies using an incision and knockout mice resulting from 129 strain mutation in a C57BL/6 strain background should have modest influence. The lack of sex differences in incisional pain may encourage researchers to use both male and female subjects in their studies.

No abstract

Postoperative pain is one of the most troublesome aspects of tonsillectomy for patients. Although various analgesics have been administered for pain control following tonsillectomy, it has still not been effectively controlled. Therefore, this study was conducted to evaluate the effectiveness of premedication using gabapentin on postoperative pain control in patients undergoing tonsillectomy. A total of 58 adult patients were randomly divided into a control group and a gabapentin group. Patients in the control group received an oral placebo preoperatively, whereas those in the gabapentin group received an oral dose of gabapentin preoperatively. All participants were provided with patient-controlled analgesia using fentanyl for 48 h after surgery. The total amount of fentanyl injected and the number of injections of dicolfenac sodium (75 mg each) requested by each of the group was then compared. Pain assessment was performed using a visual analog scale during resting periods (rVAS) and during swallowing (sVAS) for 9 days after the operation. The number of dicolfenac sodium injections and the total amount of fentanyl injected decreased significantly in the gabapentin group (P < 0.01). The sVAS of the gabapentin group was also significantly lower than that of the control group at 2 and 4 h after surgery, but there were no significant differences in the sVAS observed between the two groups for the remainder of the postoperative period. There were no significant differences in the rVAS observed between the two groups throughout the postoperative period. Thus, premedication with gabapentin decreased post-tonsillectomy pain. So the addition of gabapentin prior to tonsillectomy may have an adjunctive role in pain control.