The effect of ultrasound-guided sphenopalatine ganglion block on postoperative swelling and pain in orthognathic surgery

Introduction and Objective: Early return to daily life activities after surgery has become increasingly important. Postoperative pain and edema following orthognathic surgery can significantly restrict oral movements, thereby impairing essential functions such as nutrition, speech, and oral hygiene. This negatively affects both the recovery process and psychosocial well-being of patients. Although the sphenopalatine ganglion (SPG) block is known to be effective in pain management, there is limited evidence regarding its use in orthognathic surgery. This study aimed to evaluate the effects of ultrasound-guided suprazygomatic SPG block on postoperative pain and edema in patients undergoing bimaxillary surgery. Materials and Methods: This prospective, randomized, controlled, double-blind study was conducted at Bezmialem Vakıf University and included 50 ASA I–II patients aged 18–45 years scheduled for bimaxillary surgery. Patients were randomly assigned into two groups: the control group (Group C, n=25) received 4 mL of 0.9% saline, while the SPG group (Group SPG, n=25) received 4 mL of 0.5% bupivacaine via an ultrasound-guided suprazygomatic SPG block. Primary outcomes included numeric rating scale (NRS) pain scores and edema assessment using tragus–labial commissure (Tra–Com) and gonion–lateral canthus (Gon–LC) distances. Secondary outcomes comprised hemodynamic parameters, forehead temperature, intraoperative anesthetic and opioid consumption, intraoperative blood loss, surgical field comfort, patient-controlled analgesia (PCA) data, and postoperative nausea and vomiting scores. Results: In the assessment of edema, the percentage increase in tragus–labial commissure (Tra–Com) measurements from baseline (t0) to postoperative day 1 and day 2 was more limited in the SPG group (right side day 1–t0: p=0.009, day 2–t0: p=0.005; left side day 1–t0: p=0.007, day 2–t0: p=0.107). From postoperative day 1 and day 2 to postoperative week 1 and month 1, edema decreased in both groups; however, the rate of reduction was greater in the control group compared with the SPG group (right side month 1–day 1: p<0.001, month 1–day 2: p<0.001; left side month 1–day 1: p=0.018, month 1–day 2: p=0.228). When gonion–lateral canthus (Gon–LC) distances were compared, the differences between postoperative week 1 and month 1 measurements and postoperative day 1 and day 2 measurements were significantly greater in the control group than in the SPG group. However, no significant differences were observed when postoperative day 1 and day 2 measurements were compared with baseline (right and left Gon–LC: day 1–t0: p>0.05; day 2–t0: p>0.05; month 1–day 1: p<0.05; month 1–day 2: p<0.05). In the postoperative period, pain scores in the post-anesthesia care unit (PACU) and at the first postoperative hour were significantly lower in the SPG group compared with the control group (PACU: p=0.011; 1st hour: p=0.016). Similarly, the number of patient-controlled analgesia (PCA) demands (p=0.016) and cumulative tramadol consumption (p=0.029) at the first postoperative hour were significantly lower in the SPG group. However, no significant differences were observed between the groups in terms of pain scores or analgesic consumption during the 6–48-hour postoperative follow-up period. Following block administration, forehead temperature measurements showed a significant decrease from baseline in the SPG group (0.47±0.71 °C; p=0.001), whereas no significant change was observed in the control group. Conclusion: Ultrasound-guided SPG block is an effective method for reducing postoperative pain and edema in the early period following bimaxillary surgery. The findings suggest that the parasympathetic effects of the SPG block are more pronounced, with a greater impact on postoperative edema than on pain control. Based on these results, SPG block may be considered a useful adjunct in clinical practice for orthognathic surgical procedures. Keywords: Bimaxillary surgery, Sphenopalatine ganglion block, Postoperative pain, Edema, Suprazygomatic technique