The goal of this clinical trial is to evaluate whether sphenopalatine ganglion (SPG) block helps with intraoperative pain control, reduces postoperative edema, and decreases pain in adults aged 18 to 45 undergoing bimaxillary orthognathic surgery. The main questions it aims to answer are: * Does SPG block help decrease postoperative swelling and pain compared to a sham block? * Does it improve pain control during surgery and reduce opioid use? Researchers will compare patients receiving SPG block to those receiving a sham block to determine if this technique provides better pain relief and reduces postoperative complications. Participants will: * Be 18 to 45 years old and undergo bimaxillary orthognathic surgery. * Be randomly assigned to receive either a SPG block or a sham block before surgery. * Be monitored for 1 month after surgery to assess pain levels, swelling, opioid use, and possible complications.