Pre-emptive analgesia using local anaesthesia: a study in bilaterally symmetrical surgery

Area of Science:

• Oral and Maxillofacial Surgery
• Pain Management
• Anesthesiology

Background:

• Lower third molar extraction is a common surgical procedure often associated with postoperative pain.
• Assessing and managing pain effectively after third molar surgery is crucial for patient recovery and satisfaction.
• Understanding factors influencing postoperative pain, such as anesthetic timing, can optimize surgical outcomes.

Purpose of the Study:

• To evaluate the within-patient variation in postoperative pain intensity following bilaterally symmetrical lower third molar surgery.
• To determine if administering local anesthesia before tooth removal offers superior pain relief compared to administration after removal.
• To establish the necessary sample size for detecting significant differences in pain using visual analogue scales (VAS).

Main Methods:

• Two studies were conducted on patients undergoing bilateral lower third molar surgery under general anesthesia.
• Study 1: 40 patients assessed pain using McGill pain questionnaires and VAS on the morning after surgery.
• Study 2: 38 patients compared pain between sides receiving local anesthetic before versus after extraction, using questionnaires and VAS at multiple time points.

Main Results:

• The first study indicated that a sample size over 30 is needed to detect a >10 mm VAS difference with 90% power at a 5% significance level.
• The second study found no statistically significant differences in pain between the pretreated and post-treated sides at any measured time point.
• Pain intensity, assessed via McGill pain questionnaires and VAS, showed no significant variation based on the timing of local anesthetic administration.

Conclusions:

• Postoperative pain following lower third molar surgery does not significantly differ when local anesthesia is administered before versus after extraction.
• Adequate sample sizes are essential for detecting subtle variations in pain intensity in within-patient studies.
• Current evidence suggests the timing of local anesthetic administration in this context does not impact overall pain experience.