Effects of Dexamethasone Administration in Sphenopalatine Ganglion Block for Allergic Rhinitis: A Prospective, Randomized, Single-blind Controlled Trial.

BACKGROUND

Allergic rhinitis (AR) is a common chronic condition that significantly affects quality of life. Ultrasound-guided sphenopalatine ganglion block (SPGB) is a minimally invasive, safe, and effective treatment gaining clinical attention for symptom relief. Dexamethasone is often used in an SPGB, but its effect on autonomic nerve modulation remains unclear.

OBJECTIVES

This study aimed to assess the therapeutic effect of ultrasound-guided SPGB for treating AR and to compare the clinical efficacy and adverse reactions of dexamethasone used in conjunction with an SPGB.

STUDY

DESIGN

A prospective, randomized, single-blind controlled trial.

SETTING

Nanjing Drum Tower Hospital Clinical College of Xuzhou Medical University, People's Republic of China.

METHODS

This randomized clinical trial, involving 84 patients with AR, was conducted at Nanjing Drum Tower Hospital from February 2024 through May 2024. Patients were randomly assigned to either the experimental group (42 patients) or the control group (42 patients), with blinding applied. A total of 78 patients completed the study (40 in the experimental group, 38 in the control group). Both groups received an ultrasound-guided SPGB once a week for 4 weeks, alternating sides. The experimental group was treated with a combination of bupivacaine and dexamethasone, while the control group received only bupivacaine. Changes in efficacies, Total Nasal Symptom Score (TNSS), nasal symptom Visual Analog Scale (VAS), Rhino-conjunctivitis Quality of Life Questionnaire (RQLQ) scores, Total Nasal Respiratory Volume (TNRV), Total Nasal Volume (TNV), and Total Nasal Resistance (TNR) were measured at pretreatment and at one week, one month, 3 months, and 6 months posttreatment. Additionally, effective rate was calculated as the percentage of patients achieving a clinically meaningful response, defined as a reduction in TNSS of 30% or greater from baseline.

RESULTS

Both groups had significant reductions in TNSS, nasal symptom VAS, and RQLQ scores compared to pretreatment levels at all follow-up points (P < 0.001). At one week, one month, and 3 months posttreatment, the experimental group had higher efficacies, lower TNSS, lower VAS, and lower RQLQ scores than the control group (P < 0.05). At 6 months posttreatment, there were no significant differences between the groups for efficacy rates, VAS, or RQLQ scores (P > 0.05) while the experimental group had lower TNSS scores (P < 0.05). Both groups had significant improvement in nasal ventilation, with increases in TNRV and TNV and reductions in TNR (P < 0.001). At each follow-up, the experimental group had higher TNRV and TNV and lower TNR compared to the control group, with statistical significance observed at most time points (P < 0.05), except for TNRV at 6 months and TNV at 3 and 6 months posttreatment. Safety indicators showed no significant differences between groups (P > 0.05).

LIMITATIONS: We did not assess patient depression and anxiety; how dexamethasone over triamcinolone potentially affected efficacy; and how the absence of 3D navigation would have resulted in a safer, more precise block.

CONCLUSIONS

Ultrasound-guided SPGB is a safe and effective treatment for AR, improving symptoms, quality of life, and nasal airflow. The addition of corticosteroids may enhance short-term efficacy.