Improving the efficacy of functional endoscopic sinus surgery in chronic rhinosinusitis with nasal polyps through the combination of budesonide infiltration therapy

Abstract

Background

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a refractory inflammatory disorder often necessitating functional endoscopic sinus surgery (FESS) after inadequate response to medical therapy. This study aimed to evaluate the clinical efficacy and safety of combining FESS with intraoperative budesonide infiltration therapy in patients with CRSwNP.

Methods

A retrospective study was conducted from January 2022 to June 2024, including 209 CRSwNP patients. The observation group (n = 91) received FESS with intraoperative budesonide infiltration, while the control group (n = 118) underwent FESS alone. Clinical efficacy, olfactory function, mucociliary clearance, nasal ventilation function, complication rates, and recurrence were assessed. Data were analyzed using independent t-tests for continuous variables and Chi-square tests for categorical variables, with statistical significance set at p < 0.05.

Results

The observation group demonstrated significantly higher clinical efficacy, with a total effective rate of 87.91% compared to 66.95% in the control group (p < 0.001). Improvements were observed in olfactory function (1.08 ± 0.05 vs. 2.36 ± 0.18, p < 0.001), ciliary clearance rate (72.32 ± 6.05% vs. 66.24 ± 6.47%, p < 0.001), and ciliary clearance speed (5.51 ± 0.73 mm/min vs. 4.01 ± 0.73 mm/min, p < 0.001). Additionally, the incidence of complications was significantly lower in the observation group (4.40% vs. 12.71%, p = 0.04). No systemic corticosteroid-related adverse effects were observed.

Conclusions

FESS combined with intraoperative budesonide infiltration therapy might improve olfactory recovery, nasal function, and overall clinical efficacy, while potentially reducing postoperative complications in CRSwNP patients, suggesting it could be a safe and effective adjunctive intervention.

Introduction

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common inflammatory disorder of the sinonasal mucosa, characterized by the presence of benign polypoid growths that contribute to substantial morbidity, including nasal obstruction, facial pressure, and reduced quality of life [1]. Its pathophysiology involves chronic type-2 (T2) inflammation, typically associated with eosinophilic infiltration and overexpression of key T2-related cytokines [2], including interleukin-4 (IL-4), interleukin-5 (IL-5), and interleukin-13 (IL-13), which collectively drive polyp formation and persistence [3, 4].

Functional endoscopic sinus surgery (FESS) is widely regarded as a mainstay treatment for patients with CRSwNP who exhibit insufficient response to medical therapy [5]. By improving access to the sinus cavities, FESS facilitates mucociliary clearance and restores sinus ventilation. However, recurrence of symptoms and polyp regrowth remains common following surgery, underscoring the need for adjunctive strategies to enhance clinical outcomes [6]. Glucocorticoid infiltration therapy, in combination with FESS, has emerged as a promising approach to attenuate postoperative inflammation and reduce recurrence risk [7, 8]. Targeted local delivery of glucocorticoids provides potent anti-inflammatory effects at the surgical site, helping reduce mucosal edema and suppress early postoperative inflammatory activity [9].

While previous studies have explored systemic and topical corticosteroids as adjuncts to endoscopic sinus surgery in CRSwNP, most have focused on postoperative nasal sprays or irrigation without evaluating intraoperative budesonide infiltration [10, 11]. Furthermore, limited research has assessed long-term objective outcomes such as olfactory function, mucociliary clearance, and nasal ventilation parameters in a retrospective context [12]. To address this gap, our study investigates the clinical efficacy and safety of combining FESS with budesonide infiltration therapy, aiming to provide a comprehensive evaluation of its impact on functional outcomes and postoperative complications in patients with CRSwNP.

Methods

Study design

A retrospective evaluation was conducted at our hospital from January 2022 to June 2024 to assess the efficacy of FESS combined with glucocorticoid infiltration therapy in patients diagnosed with CRSwNP. A total of 209 CRSwNP patients were included in the study. Among these, 118 patients underwent FESS alone and were designated as the control group. The remaining 91 patients received glucocorticoid infiltration therapy in conjunction with FESS and were classified as the observation group. The research methodology, objectives, and protocols were developed in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines [13]. The study was reviewed and approved by the Ethics Committee of Zhongshan People’s Hospital (No. KY2024-268) and conducted in accordance with all relevant guidelines and regulations, including the principles of the Declaration of Helsinki. Participant confidentiality was strictly maintained, and all personal identifiers were removed prior to analysis to protect privacy. Informed consent was obtained from all participants.

Inclusion and exclusion criteria

Inclusion criteria

1. Patients aged 18 years or older diagnosed with CRSwNP according to the current European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS) criteria [14], including persistent sinonasal symptoms for ≥12 weeks and objective evidence of bilateral nasal polyps on nasal endoscopy.

2. Patients who met surgical indications by failing to respond to standardized conservative medical management, defined as persistent symptoms (nasal obstruction, rhinorrhea, hyposmia/anosmia, or facial pressure) and unchanged or worsening polyp size on endoscopy after ≥3 consecutive months of daily intranasal corticosteroid spray (mometasone furoate 200 μg/day or fluticasone propionate 200 μg/day) combined with twice-daily isotonic saline irrigation (150–200 mL per nostril per session).

3. Patients who had already undergone FESS, either alone or with intraoperative budesonide infiltration, as documented in historical treatment records.

4. Patients with complete clinical, surgical, and follow-up data available in the institutional database.

Exclusion criteria

1. Patients with a history of prior sinus surgery, including FESS, which may confound the results.

2. Patients with comorbidities that could affect the outcomes of the intervention, such as severe uncontrolled asthma or systemic diseases.

3. Patients with contraindications to glucocorticoid therapy, including known allergies or hypersensitivity to corticosteroids.

4. Patients with malignancies in the sinonasal region or adjacent structures.

Treatment methods

All surgeries in both groups were performed by the same experienced FESS surgical team.

The control group underwent FESS following standard clinical protocols. Preoperatively, patients received routine disinfection and draping, followed by endotracheal intubation under general anesthesia. All procedures were performed with the patient in the supine position. The Messerklinger technique was used to excise polypoid tissue, and additional procedures such as uncinectomy or ethmoidectomy were performed as necessary to optimize sinus drainage. Postoperatively, both nasal cavities were packed with sterile absorbable cotton and polymeric expandable sponges to achieve hemostasis, and the packing materials were removed 48 h after surgery. Beginning on postoperative day two, patients initiated isotonic saline nasal irrigation (150 mL per session, once daily), which was continued for eight weeks after surgery.

The observation group received the same surgical protocol as described above, with the addition of standardized intraoperative budesonide infiltration therapy. A commercially available budesonide suspension (Pulmicort Respules^®, AstraZeneca; 1 mg/2 mL, concentration 0.5 mg/mL) was used. For each patient, a total of 4 mL (2 mg) of budesonide suspension was prepared—2 mL (1 mg) per nasal cavity. Immediately before packing, the budesonide suspension was evenly instilled into each absorbable cotton roll and polymeric expandable sponge until fully saturated, ensuring complete infiltration of the packing material with approximately 2 mL per side. The medicated packing was then placed bilaterally in the nasal cavities in direct contact with the surgical site. The quantity and method of infiltration were standardized across all cases, with all procedures performed or supervised by senior attending surgeons to ensure uniform technique.

Following removal of the packing materials 48 h after surgery, patients continued local glucocorticoid therapy using a budesonide nasal spray (64 µg per spray, two sprays per nostril, twice daily) for six months. Adherence to the postoperative glucocorticoid regimen was reinforced at each follow-up visit. This combined surgical and pharmacological approach was designed to provide immediate postoperative anti-inflammatory effects while maintaining long-term suppression of polyp recurrence.

Aside from the standardized intraoperative budesonide infiltration and the postoperative budesonide nasal spray used only in the observation group, all other aspects of postoperative care, including saline irrigation protocol, debridement schedule, and the use of concomitant medications, were identical between groups throughout the 12-month follow-up. No systemic corticosteroids or additional rescue medications were prescribed to either group unless clinically required for unrelated conditions.

Data collection and variables examined

The improvement in olfactory function score was prespecified as the primary endpoint, whereas all other assessed parameters, including mucociliary clearance (ciliary clearance rate and speed), nasal ventilation metrics (nasal minimum cross-sectional area [NMCA], nasal cavity volume [NCV], distance from the minimum cross-section to the anterior nostril [DCAN], and nasal airway resistance), clinical efficacy, complication incidence, and recurrence rate, were designated as secondary endpoints.

Clinical efficacy

Clinical efficacy was assessed using predefined criteria to evaluate the treatment outcomes of the two groups. A patient was classified as markedly effective if there was a complete resolution of clinical symptoms, with endoscopic examination showing patent sinus cavities, complete epithelialization of the surgical site, and absence of purulent discharge. Patients were classified as effective if they experienced significant alleviation of symptoms, although sinus ostia remained partially patent, with only minimal purulent discharge observed. Conversely, those categorized as ineffective exhibited no improvement or worsening of clinical symptoms despite treatment. The total effective rate was calculated using the formula: Total Effective Rate = (Number of Effective + Number of Improved Cases) / Total Number of Cases × 100%.

Olfactory function

Olfactory function was evaluated utilizing the Japanese T&T olfactory test, which classifies olfactory performance into several categories based on test scores [15–17]. A score ranging from 0.0 to 1.0 indicates normal olfactory function, while scores from 1.1 to 2.5 reflect mild olfactory impairment. Scores between 2.6 and 4.0 denote moderate impairment, and scores from 4.1 to 5.5 indicate severe impairment. Scores exceeding 5.5 represent complete loss of olfactory function. This assessment is crucial for understanding the impact of treatments on sensory capabilities.

Nasal mucosal function

Nasal mucosal function was evaluated through the saccharin test, which measures ciliary clearance rates and clearance velocity. This test was conducted before and after treatment to ascertain the functional improvements in nasal mucosa between the two groups. Effective ciliary function is essential for maintaining mucosal health and ensuring the clearance of secretions, thus enhancing overall nasal function.

Nasal ventilation function

Nasal ventilation function was measured pre- and post-treatment using a rhinomanometer. Key parameters assessed included the NMCA, NCV, and DCAN. Additionally, nasal airway resistance was evaluated via anterior nasal pressure measurement. These metrics provide valuable insights into the effectiveness of the interventions on nasal airflow and ventilation, which are critical for respiratory health.

Complications

The study also focused on the incidence of complications occurring during the treatment period. A comparative analysis was conducted between the two groups to identify any adverse effects associated with either treatment approach. Epistaxis was defined as any postoperative nasal bleeding requiring medical intervention beyond routine postoperative care.

Recurrence

To assess long-term outcomes, patients were followed up for 12 months post-treatment to compare recurrence rates between the two groups.

Outcome assessments were conducted at standardized time points:

1. Olfactory Function (T&T olfactory test): Assessed preoperatively and at 1, 3, 6, and 12 months postoperatively.

2. Mucociliary Clearance (saccharin transit time): Measured preoperatively and at 1, 3, 6, and 12 months postoperatively to evaluate nasal mucosal function.

3. Nasal Ventilation Function (rhinomanometry): Parameters including NMCA, NCV, DCAN, and nasal airway resistance were measured preoperatively and at 1, 3, 6, and 12 months postoperatively.

4. Nasal Endoscopy (Lund–Kennedy score): Performed at all follow-up visits (1, 3, 6, and 12 months) to evaluate postoperative healing, complications, and recurrence.

5. Complications (e.g., epistaxis, synechiae, ostial obstruction): Evaluated at each postoperative visit, with documentation of any adverse events requiring medical attention.

6. Clinical Efficacy: Determined at 6 and 12 months based on symptom resolution, endoscopic findings, and physician global assessment.

7. Recurrence: Defined as the reappearance of nasal polyps, confirmed by both clinical symptoms (such as nasal obstruction, rhinorrhea, or facial pressure) and endoscopic findings, assessed at 12 months postoperatively.

To minimize the risk of measurement bias, the investigators responsible for data extraction and outcome assessment were blinded to the patients’ treatment allocation. All clinical and functional outcome data were retrieved from medical records in a manner that concealed whether the patient had undergone FESS alone or FESS with budesonide infiltration. All patients who met the inclusion criteria and completed the surgical intervention were included in the analysis. Follow-up data were collected at 1, 3, 6, and 12 months postoperatively. Patients who missed a scheduled follow-up visit were contacted via telephone, and outpatient medical records were reviewed to obtain outcome information where possible. Missing data for a given outcome at a specific time point were excluded from the analysis for that variable, but the patient’s available data at other time points were retained (per-protocol approach). Sensitivity analyses were performed for the primary outcome measure (olfactory function score improvement) by imputing missing values using the last observation carried forward (LOCF) method, and results were compared with the complete-case analysis to assess robustness.

Statistical analysis

Statistical analyses were performed using SPSS software (Version 27.0). Given the retrospective observational design of this study, a per-protocol analytical approach was employed. Only patients who met al.l inclusion and exclusion criteria and completed both the surgical intervention and follow-up assessments were included in the final analysis. For continuous data exhibiting a normal distribution, inter-group differences were evaluated using independent sample t-tests. Results are presented as mean ± standard deviation (SD) [18]. For categorical data, the Chi-square (χ²) test was used to examine the relationships between variables, with Fisher’s exact test applied when the Chi-square test assumptions were not met [19]. Two-sided 95% confidence intervals (CIs) were calculated for all between-group comparisons to estimate the precision of the observed differences and to facilitate clinical interpretation. Confidence intervals for continuous variables were calculated from the mean difference between groups using the pooled standard error. A post hoc power analysis was conducted based on the primary outcome of olfactory function score improvement. The analysis confirmed that the study had sufficient statistical power (1 - β >0.95) to detect clinically meaningful differences with a two-sided α level of 0.05. Since multiple outcome variables were analyzed, the Bonferroni correction was applied to adjust for multiple comparisons and control the family-wise Type I error rate. The adjusted significance threshold (α_adj) was calculated by dividing the conventional α level (0.05) by the number of primary outcome comparisons. Statistical significance was considered if the p-value met the adjusted significance threshold. The primary outcome analysis used a per-protocol approach, excluding patients with missing data at specific time points. Missing data for sensitivity analysis were imputed using the Last Observation Carried Forward (LOCF) method. All statistical hypotheses were two-tailed, with p-values less than 0.05 considered indicative of statistical significance.

Results

Patient demographics and clinical characteristics

A total of 209 patients met the inclusion criteria and were assigned to the observation group (n = 91) or the control group (n = 118) (Fig. 1). Baseline demographic and clinical characteristics are summarized in Table 1. The observation group consisted of 43 males and 48 females, while the control group included 54 males and 64 females. The mean age was 46.51 ± 6.98 years in the observation group and 47.09 ± 7.11 years in the control group. Mean disease duration was 4.66 ± 1.28 years and 4.62 ± 1.34 years, respectively. The distribution of clinical classifications (Type I–III) was comparable between groups. Preoperative functional measurements, including olfactory function score, ciliary clearance rate, ciliary clearance speed, NMCA, NCV, DCAN, and nasal airway resistance, showed no statistically significant differences between groups (all p > 0.05). Baseline endoscopic findings assessed by the Lund–Kennedy score were similar between groups. Comorbid conditions, including allergic rhinitis and asthma, demonstrated comparable prevalence in both cohorts. Body mass index (BMI) and smoking history were also similar. In addition, preoperative medical therapy, specifically intranasal corticosteroid use and saline irrigation for ≥ 3 months, and systemic corticosteroid exposure within the past 3 months showed no significant between-group differences. Operative duration was 2.5 ± 0.9 h in the observation group and 2.7 ± 1.3 h in the control group, with no statistically significant difference. Overall, no significant differences were observed in any baseline demographic or clinical variables between the two groups, indicating comparability at the start of the study. The proportion of missing data for any single outcome measure was ≤ 5%. Missing data for the primary outcome (olfactory function score) were imputed using the LOCF method for sensitivity analysis, and these results were consistent with the complete-case analysis.

Fig. 1.

Flowchart of Study Participant Selection and Grouping

Table 1.

Demographics and clinical characteristics of patients in the observation and control groups

Characteristic	Observation Group (n = 91)	Control Group (n = 118)	p-value
Gender [n (%)]
Male	43 (47.25)	54 (45.76)	0.82
Female	48 (52.75)	64 (54.24)
Age (years)	46.51 ± 6.98	47.09 ± 7.11	0.54
Disease Duration (years)	4.66 ± 1.28	4.62 ± 1.34	0.78
Clinical Classification [n (%)]
Type I	39 (42.86)	51 (43.22)	0.99
Type II	31 (34.07)	42 (35.59)
Type III	21 (23.08)	25 (21.19)
Preoperative Olfactory Function Score	4.15 ± 0.49	4.23 ± 0.51	0.25
Preoperative Ciliary Clearance Rate (%)	46.38 ± 5.27	47.16 ± 4.85	0.27
Preoperative Ciliary Clearance Speed (mm/min)	2.12 ± 0.59	2.23 ± 0.54	0.16
Preoperative NMCA (cm²)	0.45 ± 0.05	0.44 ± 0.04	0.11
Preoperative NCV (cm³)	10.18 ± 0.88	10.30 ± 0.75	0.29
Preoperative DCAN (cm)	1.82 ± 0.18	1.83 ± 0.22	0.73
Preoperative Nasal Airway Resistance (kPa/L·s)	2.85 ± 0.49	2.77 ± 0.46	0.23
Lund–Kennedy Score	5.92 ± 1.14	6.01 ± 1.21	0.53
Allergic Rhinitis	28 (30.77%)	35 (29.66%)	0.86
Asthma	12 (13.19%)	17 (14.41%)	0.82
BMI (kg/m²)	23.74 ± 2.98	23.92 ± 3.05	0.65
Smoking History	15 (16.48%)	22 (18.64%)	0.69
Intranasal Corticosteroid Use (≥ 3 months)	91 (100%)	118 (100%)	1.00
Saline Irrigation Use (≥ 3 months)	91 (100%)	118 (100%)	1.00
Systemic Corticosteroid Use (last 3 months)	7 (7.69%)	10 (8.47%)	0.83
Operative Duration (hours)	2.5 ± 0.9	2.7 ± 1.3	0.19

NMCA Nasal minimum cross-sectional area, NCV Nasal cavity volume, DCAN Distance from minimum cross-section to anterior nostril

Improvement in olfactory Function, ciliary clearance Rate, and ciliary clearance speed

The results of this study indicate that the combination of FESS with budesonide infiltration therapy significantly improves olfactory function, ciliary clearance rate, and ciliary clearance speed in patients with CRSwNP compared to FESS alone. Before treatment, there were no significant differences between the observation and control groups in terms of olfactory function score, ciliary clearance rate, or ciliary clearance speed (P > 0.05). However, after treatment, the observation group demonstrated significantly greater improvements in all three parameters. The olfactory function score in the observation group was markedly lower (1.08 ± 0.05) compared to the control group (2.36 ± 0.18, Mean Difference = -1.28, 95% CI: -1.31 to -1.25, P < 0.001), indicating better recovery of olfactory function. Similarly, the ciliary clearance rate improved more in the observation group (72.32 ± 6.05%) compared to the control group (66.24 ± 6.47%, Mean Difference = 6.08%, 95% CI: 4.37 to 7.79, P < 0.001), as did the ciliary clearance speed (5.51 ± 0.73 mm/min in the observation group vs. 4.01 ± 0.73 mm/min in the control group, Mean Difference = 1.50 mm/min, 95% CI: 1.30 to 1.70, P < 0.001) (Table 2).

Table 2.

Comparison of olfactory function Scores, ciliary clearance Rates, and ciliary clearance speeds before and after treatment in patients with chronic rhinosinusitis with nasal polyps (Mean ± SD)

Indicator	Observation Group (n = 91)	Control Group (n = 118)	Mean Difference	95% CI	t-value	p-value
Olfactory Function Score (points)
Before Treatment	4.15 ± 0.49	4.23 ± 0.51	-	-	1.144	0.254
After Treatment	1.08 ± 0.05*	2.36 ± 0.18*	-1.28	-1.31 to -1.25	65.87	< 0.001
Ciliary Clearance Rate (%)
Before Treatment	46.38 ± 5.27	47.16 ± 4.85	-	-	1.110	0.268
After Treatment	72.32 ± 6.05*	66.24 ± 6.47*	6.08	4.37 to 7.79	6.928	< 0.001
Ciliary Clearance Speed (mm/min)
Before Treatment	2.12 ± 0.59	2.23 ± 0.54	-	-	1.402	0.162
After Treatment	5.51 ± 0.73*	4.01 ± 0.73*	1.50	1.30 to 1.70	14.73	< 0.001

Comparison of olfactory function scores, ciliary clearance rates, and ciliary clearance speeds before and after treatment in patients with chronic rhinosinusitis with nasal polyps (mean ± SD)

*P < 0.05 indicates a significant difference between the observation and control groups after treatment (independent sample t-test)

Improvement in nasal ventilation function indicators

The combination of FESS with budesonide infiltration therapy yielded significant improvements in nasal ventilation function indicators compared to FESS alone. Baseline measurements of NMCA, NCV, DCAN, and nasal airway resistance showed no statistically significant differences between the observation and control groups (P > 0.05), indicating comparable starting conditions. Following treatment, the observation group exhibited significantly enhanced NMCA, increasing to 0.62 ± 0.11 cm², compared to 0.54 ± 0.09 cm² in the control group (P < 0.001). Similarly, NCV improved markedly in the observation group, reaching 18.05 ± 2.10 cm³, while the control group achieved a lower post-treatment volume of 13.50 ± 1.92 cm³ (P < 0.001). The DCAN measurements indicated a greater reduction in the observation group, with a final average of 0.91 ± 0.12 cm, compared to 1.43 ± 0.17 cm in the control group (P < 0.001). Furthermore, nasal airway resistance significantly decreased in the observation group to 1.02 ± 0.13 kPa/L·s, contrasting with the control group’s 1.80 ± 0.20 kPa/L·s (P < 0.001) (Table 3).

Table 3.

Comparison of nasal ventilation function indicators before and after treatment in patients with chronic rhinosinusitis with nasal polyps (Mean ± SD)

Indicator	Observation Group (n = 91)	Control Group (n = 118)	Mean Difference	95% CI	t-value	p-value
NMCA (cm²)
Before Treatment	0.45 ± 0.05	0.44 ± 0.04	-	-	1.606	0.110
After Treatment	0.62 ± 0.11*	0.54 ± 0.09*	0.08	0.05 to 0.11	5.781	< 0.001
NCV (cm³)
Before Treatment	10.18 ± 0.88	10.30 ± 0.75	-	-	1.063	0.289
After Treatment	18.05 ± 2.10*	13.50 ± 1.92*	4.55	4.00 to 5.10	16.30	< 0.001
DCAN (cm)
Before Treatment	1.82 ± 0.18	1.83 ± 0.22	-	-	0.352	0.725
After Treatment	0.91 ± 0.12*	1.43 ± 0.17*	-0.52	-0.56 to -0.48	24.80	< 0.001
Nasal Airway Resistance (kPa/L·s)
Before Treatment	2.85 ± 0.49	2.77 ± 0.46	-	-	1.212	0.227
After Treatment	1.02 ± 0.13*	1.80 ± 0.20*	-0.78	-0.82 to -0.74	32.30	< 0.001

NMCA Nasal minimum cross-sectional area, NCV Nasal cavity volume, DCAN Distance from minimum cross-section to anterior nostril

Comparison of nasal ventilation function indicators before and after treatment in patients with chronic rhinosinusitis with nasal polyps (mean ± SD)

*P < 0.05 indicates a significant difference between the observation and control groups after treatment (independent sample t-test)

Clinical efficacy in patients with chronic rhinosinusitis with nasal polyps

The clinical efficacy of treatment in patients with CRSwNP was significantly greater in the observation group, which received FESS combined with budesonide infiltration therapy, compared to the control group, which underwent FESS alone. In the observation group (n = 91), the total effective rate, defined as the sum of markedly effective and effective cases, was 87.91%, with 54 patients (59.34%) showing markedly effective results and 26 patients (28.57%) showing effective results. Only 11 patients (12.09%) in this group were classified as ineffective. In contrast, the control group (n = 118) had a significantly lower total effective rate of 66.95%. In this group, 47 patients (39.83%) were classified as markedly effective, 32 patients (27.12%) as effective, and a much higher proportion of patients (33.05%) were classified as ineffective. The difference in total effective rates between the two groups was statistically significant (χ² = 12.41, P < 0.001) (Table 4). These findings suggest that the addition of budesonide infiltration therapy to FESS significantly improves clinical outcomes, with a higher proportion of patients achieving effective treatment results and a lower rate of treatment failure compared to FESS alone.

Table 4.

Comparison of clinical efficacy in patients with chronic rhinosinusitis with nasal polyps [n (%)]

Group	Markedly Effective	Effective	Ineffective	Total Effective
Observation Group (n = 91)	54 (59.34)	26 (28.57)	11 (12.09)	80 (87.91)
Control Group (n = 118)	47 (39.83)	32 (27.12)	39 (33.05)	79 (66.95)
χ²-value	-	-	-	12.41
p-value	-	-	-	< 0.001

Complication incidence in patients with chronic rhinosinusitis with nasal polyps

The incidence of complications following treatment was significantly lower in the observation group, which received FESS with budesonide infiltration therapy, compared to the control group, which underwent FESS alone. In the observation group (n = 91), the total incidence of complications was 4.40%, with low rates of individual complications: epistaxis (2.20%), nasal adhesion (1.10%), and ostial obstruction (1.10%). In contrast, the control group (n = 118) demonstrated a higher overall complication rate of 12.71%. Specific complications in this group included higher occurrences of nasal adhesion (5.93%), epistaxis (3.39%), and ostial obstruction (3.39%). The difference in total complication rates between the two groups was statistically significant (χ² = 4.30, P = 0.04). In our study, no systemic corticosteroid-related adverse effects, such as mucosal atrophy, delayed mucosal healing, or signs of systemic steroid absorption, were observed in either group throughout the 12-month follow-up period. These results indicate that the addition of budesonide infiltration to FESS not only improves clinical efficacy but also reduces the incidence of postoperative complications, supporting its use as a safer and more effective approach for managing CRSwNP (Table 5).

Table 5.

Comparison of complication incidence in patients with chronic rhinosinusitis with nasal polyps [n (%)]

Group	Epistaxis	Nasal Adhesion	Ostial Obstruction	Total Incidence
Observation Group (n = 91)	2 (2.20)	1 (1.10)	1 (1.10)	4 (4.40)
Control Group (n = 118)	4 (3.39)	7 (5.93)	4 (3.39)	15 (12.71)
χ²-value	-	-	-	4.30
p-value	-	-	-	0.04

Post hoc statistical power and Bonferroni-Adjusted significance of primary outcomes

A post hoc power analysis was conducted for the primary outcome measure, the improvement in olfactory function score. The analysis showed that the achieved statistical power (1 – β) exceeded 0.95 (≥ 0.80) at a two-sided α level of 0.05. This calculation was based on the observed mean difference between the observation and control groups (1.28 points) and the pooled standard deviation (0.14). Despite the unequal group sizes (91 vs. 118), the high power value indicates that the sample size was sufficient to detect clinically meaningful differences, thereby supporting the validity of the statistical findings.

After applying the Bonferroni correction (adjusted α = 0.0071), all primary outcome differences between the observation and control groups remained statistically significant. Specifically, improvements in olfactory function score (p < 0.001), ciliary clearance rate (p < 0.001), ciliary clearance speed (p < 0.001), NMCA (p < 0.001), NCV (p < 0.001), DCAN (p < 0.001), and nasal airway resistance (p < 0.001) all met the adjusted significance threshold.

Discussion

CRSwNP is a persistent inflammatory disorder characterized by nasal obstruction, excessive mucus secretion, and olfactory dysfunction, all of which significantly impair patients’ quality of life [14, 20]. FESS has become the primary surgical intervention for patients unresponsive to medical management. It aims to remove obstructions, restore sinus drainage, and improve nasal ventilation [21, 22]. However, despite its clinical efficacy, postoperative recurrence of nasal polyps and persistent mucosal inflammation remain frequent challenges. These issues often necessitate adjunctive therapies or revision surgeries. In recent years, intraoperative glucocorticoid therapy, particularly via local infiltration, has garnered increasing attention for its potential to enhance FESS outcomes [23–25]. Glucocorticoids, such as budesonide, exert potent local anti-inflammatory effects. They work by inhibiting proinflammatory cytokine expression, reducing vascular permeability, and suppressing eosinophil infiltration. When administered intraoperatively, budesonide infiltration facilitates mucosal healing, limits polyp regrowth, and improves long-term nasal function [26, 27]. The present study demonstrates that FESS combined with intraoperative budesonide infiltration significantly improves clinical outcomes in CRSwNP patients compared to FESS alone. Observed benefits include enhanced olfactory function, increased mucociliary clearance rates and velocities, improved nasal airflow parameters, and a reduction in postoperative complications. These improvements are likely attributable to the anti-inflammatory and tissue-stabilizing effects of budesonide, which may mitigate postoperative inflammation and recurrence risk. In this study, olfactory function was assessed using the Japanese T&T olfactometer test, a validated and standardized psychophysical method that quantitatively measures odor detection and recognition thresholds [16]. Although it is not as widely used globally as some other olfactory tests (e.g., Sniffin’ Sticks, UPSIT), the T&T test has been extensively applied in clinical and research settings in East Asia, including China and Japan, and has demonstrated good reliability, reproducibility, and sensitivity in detecting olfactory impairment in patients with CRSwNP. Its use in our study population was based on local availability, established laboratory protocols, and prior validation in similar Chinese cohorts, ensuring the appropriateness and accuracy of olfactory assessment in this context [17].

The greater improvements in olfactory function, ciliary clearance rate, and ciliary clearance speed observed in the observation group suggest that intraoperative budesonide infiltration may contribute to the restoration of nasal physiology. Budesonide, a potent corticosteroid, downregulates type-2, eosinophil-predominant inflammatory pathways. This reduces mucosal edema and limits inflammatory-cell trafficking. These effects could help preserve the functional integrity of the olfactory epithelium and enhance ciliary activity. Improved ciliary function, reflected by higher clearance rates and velocities, is clinically relevant. Ciliary dysfunction promotes mucus stasis and bacterial colonization, which perpetuate chronic inflammation. Therefore, budesonide infiltration may offer a dual benefit: supporting recovery of olfaction and augmenting mucociliary clearance. Both of these factors are critical for long-term disease control. Regarding nasal ventilation metrics, significant post-treatment gains in NMCA and NCV, along with decreases in the DCAN and nasal airway resistance, indicate improved airflow and reduced obstruction in the observation group. These changes align with the known anti-inflammatory actions of corticosteroids, which decrease tissue swelling and vascular permeability. These actions enhance sinus patency [28]. The reduction in nasal airway resistance further underscores the potential of the combined approach to alleviate airflow limitation, improving respiratory function and quality of life.

Clinical efficacy, as measured by the total effective rate, was notably higher in the observation group than in the control group. The observation group achieved an effective rate of 87.91%, compared to 66.95% in the control group. This disparity may be attributed to the sustained anti-inflammatory effects of budesonide, which likely contribute to reduced recurrence and improved postoperative outcomes. By inhibiting proinflammatory cytokine release, budesonide modulates the chronic eosinophilic inflammation characteristic of CRSwNP. This action supports more durable symptom control and mucosal healing [29, 30]. The lower proportion of ineffective cases in the observation group further suggests that intraoperative budesonide infiltration may more comprehensively address the underlying inflammatory pathology. This enhances the long-term effectiveness of FESS and potentially decreases the need for repeat interventions. In addition, the incidence of postoperative complications was significantly lower in the observation group. The total complication rate was 4.40% in the observation group, compared to 15.25% in the control group. Budesonide infiltration appears to exert a protective effect against common FESS-associated complications, such as nasal adhesion and epistaxis. This effect is likely mediated by its anti-inflammatory properties, which reduce mucosal fragility and vascular congestion. These properties minimize postoperative bleeding and tissue trauma [31]. Furthermore, the local suppression of inflammation at the surgical site may help prevent adhesion formation and promote mucosal remodeling. The reduced incidence of ostial obstruction in the observation group also suggests that budesonide may preserve sinus ostium patency by limiting peristomal inflammation. This, in turn, decreases the risk of postoperative obstruction and secondary infection.

Several recent studies have highlighted the benefits of adjunctive therapies to enhance surgical outcomes in CRSwNP. Liao et al. [12] reported that postoperative budesonide suspension significantly improved olfactory function, nasal ventilation, and reduced recurrence rates when added to endoscopic sinus surgery. Our findings are consistent with these results; however, we present a novel approach of intraoperative budesonide infiltration, which offers an earlier and more direct anti-inflammatory benefit. This method allows for immediate anti-inflammatory effects at the surgical site, potentially accelerating mucosal recovery and reducing the incidence of postoperative complications. In contrast, postoperative treatments such as irrigation are delayed in their action, and their effectiveness is reliant on patient adherence. Gnanasekaran et al. [32] conducted a meta-analysis demonstrating the efficacy of postoperative budesonide nasal irrigation post-FESS. However, the heterogeneity of irrigation protocols and patient compliance issues limit its practicality. Our standardized intraoperative infiltration technique ensures consistent delivery of the medication and circumvents these issues. Moreover, Yang et al. [33] showed that postoperative omalizumab improved symptom control in CRSwNP patients with asthma, highlighting the effectiveness of adjunctive anti-inflammatory strategies. While biologics offer promising outcomes, our intraoperative budesonide infiltration remains a more cost-effective, widely accessible, and pragmatic option, suitable for broader clinical use. Collectively, these comparisons underscore the novelty and clinical value of combining FESS with intraoperative budesonide infiltration as a safe, effective, and practical strategy to improve CRSwNP outcomes.

Overall, the findings of this study underscore the potential synergistic benefits of combining budesonide infiltration with FESS in the management of CRSwNP. The pharmacologic properties of budesonide as a corticosteroid provide targeted anti-inflammatory effects, enhance mucociliary clearance, and help maintain nasal airway patency, thereby contributing to improved short- and long-term clinical outcomes. From a clinical standpoint, integrating intraoperative budesonide infiltration into FESS protocols may represent an effective strategy to optimize treatment efficacy and reduce postoperative complications in patients with CRSwNP. This study has several limitations. First, its retrospective and non-randomized nature limits causal inference. Although strict inclusion and exclusion criteria were uniformly applied and all eligible patients within a defined time window were consecutively identified, selection bias cannot be entirely ruled out. The absence of matching, multivariable adjustment, or propensity score analysis means that residual confounding from unmeasured factors, such as subtle variations in postoperative care, environmental exposures, or comorbid conditions, may have influenced outcomes. Nonetheless, baseline demographic and clinical characteristics were comparable between groups, and all surgeries were performed by the same experienced surgical team using standardized perioperative protocols, which helped reduce treatment-related variability. Second, this was a single-center study with unequal group sizes, which may limit generalizability. Regional differences in patient demographics, clinical practice patterns, and healthcare resources may affect the applicability of the findings to other populations. Future multi-center studies with more balanced group sizes are needed to enhance external validity. Third, although the study included a 12-month follow-up period that is sufficient to evaluate early postoperative recovery and short-term recurrence, CRSwNP is a chronic disease in which recurrence may occur over several years. Longer-term follow-up is planned as part of our institutional surveillance program to determine whether the early benefits of intraoperative budesonide infiltration are sustained over time. Finally, while no systemic corticosteroid-related adverse effects were observed in this cohort, systemic absorption and long-term safety of repeated or prolonged corticosteroid exposure were not comprehensively evaluated. Future research should incorporate detailed assessments of potential systemic effects. In addition, emerging controlled-release corticosteroid delivery systems, including steroid-eluting implants and sustained-release biodegradable matrices, represent promising avenues for further improving postoperative anti-inflammatory control. Prospective randomized controlled trials with extended follow-up, multi-center collaboration, and integration of advanced drug-delivery technologies are required to validate and expand upon the findings of the present study.

Conclusions

In conclusion, FESS combined with budesonide infiltration therapy could provide enhanced clinical benefits in the management of CRSwNP. This combined approach might improve olfactory function, enhance nasal ventilation, and reduce postoperative complication rates, suggesting a potentially safer and more effective therapeutic option compared to FESS alone.

Authors’ contributions

Jing-Jing Cun and Jian-Hui Wu initiated the study concept. Together with Qi Cui Wu and Qian Pan, they played a significant role in the literature search, data extraction, quality assessment, data analysis, and manuscript preparation. Zhong Pan, Jian-Hui Wu, and Xin Li contributed to refining the manuscript’s language, style, and protocol. Jing-Jing Cun and Jian-Hui Wu also facilitated analytical discussions. The manuscript’s final revision and approval were carried out by Rong Chen and Min-Yi Fu.

Funding

None.

Data availability

The data sets generated and analyzed during this study are not public, but under reasonable requirements, the correspondence author can provide.

Declarations

Ethics approval and consent to participate

This study was approved by the Ethics Committee of Zhongshan People’s Hospital (No. KY2024-268). All research procedures involving human participants complied with the ethical standards of our institution and the 1964 Helsinki Declaration and its subsequent amendments. Informed consent was secured from all participants.

Consent for publication

Informed consent was obtained from all subjects.

Competing interests

The authors declare no competing interests.