Survey population and product use
A total of 100 patients were enrolled in the survey. The mean age was 33.7 ± 9.4 years, with an age range of 7–60 years, including 6 pediatric patients (age range: 7–17 years). Of the 96 participants, who provided valid responses for sex distribution, 55 were male (57.3%) and 41 were female (42.7%) (Figure 1A, 1B).

Overall, 140 ENT-related conditions were reported, as some patients presented with more than one condition. Based on the total number of reported conditions, common cold/flu was the most frequent indication (35.0%; n = 49), followed by rhinosinusitis (25.0%; n = 35), allergies (18.6%; n = 26), nasal hygiene and moisturization (11.4%; n = 16), post-endonasal surgery recovery (4.3%; n = 6), other conditions (4.3%; n = 6), and allergic rhinitis (1.4%; n = 2) (Figure 1C). Most of the patients reported a single condition (72.4%; n = 71), while 27 patients (27.6%) presented with two or more concurrent ENT-related conditions; three patients reported four concurrent conditions (Figure 1D). The most frequent combinations were allergies with rhinosinusitis and common cold/flu with rhinosinusitis, each reported by 10 patients, followed by allergies with common cold/flu and common cold/flu with nasal hygiene and moisturization, each reported by 9 patients (Table 1). A detailed summary of patient conditions and condition combinations is provided in Table 1.

Overall, 57 patients (57.0%) used ISS alone and 43 (43.0%) used it concurrently with prescribed medication (Figure 2A). The mean duration of ISS use was 8.6 days (median: 7 days; SD: 6.8; range: 2–30 days). Most patients (n = 81) used ISS for 5–10 days (67.9%), followed by 1–4 days (18.5%), 26–30 days (7.4%), 11–15 days (4.9%), and 16–20 days (1.2%) (Figure 2B). Among patients with valid responses who used ISS with medication (n = 32), 62.5% administered it more than three times daily, whereas 37.5% used it 1–3 times per day. In the group that used ISS without medication (n = 39), 43.6% administered ISS more than three times daily and 56.4% used it 1–3 times per day (Figure 2C). Regarding timing of administration in patients using ISS with medication, 65.2% used ISS prior to their prescribed medication, while 34.8% administered it between medication doses (Figure 2D).

Sinonasal and Quality-of-Life Symptom Improvement
Following ISS use, statistically significant improvements were observed across all sinonasal and quality-of-life symptoms (p < 0.0001 for all comparisons), demonstrating a consistent and wide-ranging beneficial response across the different ENT conditions represented in this cohort.

Among sinonasal symptoms, the highest improvements were recorded for stuffy nose and runny nose, which decreased by 1.73 points (57.6%) and 1.74 points (57.1%), respectively. Sneezing, nasal itching, and other problems (e.g., watery eyes, sore throat, reduced taste or smell) also showed marked reductions, with decreases of 1.47, 1.41, and 1.18 points (50.8%, 50.8%, and 53.2%), confirming the efficacy of ISS (Figure 3A, 3B).

Beyond nasal symptoms, ISS use was also associated with significant improvements across the assessed quality-of-life parameters (e.g., fatigue, reduced productivity, poor sleep, emotional state, and overall feeling). The greatest relative improvement was observed for overall feeling, which decreased by 1.59 points (63.0%), followed by fatigue (−1.40 points; 59.9%), reduced productivity (−1.24 points; 56.4%), emotional state (−1.31 points; 54.9%), and poor sleep (−1.42 points; 51.1%) (Figure 3C, 3D).

Regarding onset of symptom relief, 24 patients (24.2%) reported improvement in less than 5 minutes, 49 (49.5%) within up to 30 minutes, 24 (24.2%) after more than 30 minutes, and 2 (2.0%) reported no improvement (Figure 4A). The majority of patients who reported improvement during ISS use (n = 97) first experienced relief by Day 2 (39.2%), followed by Day 1 (26.8%) and Day 3 (25.8%), with only a small proportion reporting first improvement at Day 5 or Day 7 (4.1% each) (Figure 4B). The cumulative proportion of patients reporting symptoms relief increased over time, from 26.8% at Day 1 to 91.8% at Day 3, reaching 100% by Day 7 (Figure 4C). To further investigate whether the frequency of ISS use influenced the degree of symptom improvement, outcomes were compared between patients using ISS more than three times per day (n = 37) and those using it 1–3 times per day (n = 34). Across most sinonasal and QoL parameters, patients in the higher-frequency group showed numerically greater improvements from baseline, with statistically significant between-group differences observed for other symptoms (e.g., watery eyes, sore throat, reduced taste or smell) (77.5% vs. 47.5%; p < 0.01) and productivity (75.0% vs. 50.9%; p < 0.05) (Figure 4D). For the remaining parameters, a tendency toward greater improvement was observed in the higher-frequency group, however the differences did not reach statistical significance, while sneezing showed comparable improvement between groups (51.1% vs. 57.6%) (Figure 4D). Overall, these findings suggest a trend toward greater benefit with more frequent ISS use; however, data need to be confirmed in other and/or larger studies.

Considering medication use, the majority of patients reported that ISS contributed to a reduction in concomitant medication intake (Figure 5A). Among patients using ISS alongside medication (n = 43), 86.0% reported reduced medication use (Absolutely Yes: 2.3%; Yes: 53.5%; Maybe Yes: 30.2%), with limited negative responses (Maybe Not: 7.0%; Not: 7.0%). Similar trends were also observed among patients using ISS alone (Figure 5A). Concomitant medications primarily included antihistamines/antiallergic agents (45.5%), followed by analgesics/pain relief medications (18.2%) and nasal corticosteroids (15.2%) (data not shown). Furthermore, 79% (Absolutely Yes: 4.7%; Yes: 44.2%; Maybe Yes: 30.2%) of patients using ISS alongside medication and 93% (Absolutely Yes 15.8%; Yes: 59.6%; Maybe Yes: 17.5%) of those using ISS without concomitant therapy expressed willingness to use ISS as a standalone treatment option (Figure 5B). Taken together, these findings indicate that ISS provides rapid and broad symptom relief, with a high proportion of patients reporting that ISS could be considered as a standalone therapy, without additional medication.

Consumer Satisfaction and Ease of Use
Analysis of product efficacy demonstrated high levels of patient satisfaction, with 60.6% of patients reporting being very satisfied and an additional 5.1% reporting being extremely satisfied (Figure 6A). Similarly, satisfaction-related responses among participants using ISS indicated a generally positive user experience. Specifically, 54.5% of respondents were very satisfied with ISS use, while 9.1% were extremely satisfied, corresponding to a combined strongly positive satisfaction rate of 63.6%. An additional 24.2% of participants reported being somewhat satisfied (Figure 6A). In contrast, only a small proportion of users expressed dissatisfaction, with 9.1% reporting being very dissatisfied and 1.0% extremely dissatisfied (Figure 6A).

The product was rated as easy to use by the majority of participants, with 90.0% reporting positive usability (Absolutely Yes 33.3%; Yes 56.7%). In contrast, only a small proportion of participants (2.2%) reported any difficulty in use (Figure 6B). Consistent with these findings, participants also demonstrated a high likelihood of recommending or purchasing the product, with 88.0% expressing positive intent (Absolutely Yes 42.9%; Yes 45.1%), while only a small minority reported negative responses (Not 2.2%; Absolutely Not 1.1%), and 9.9% remained uncertain (Maybe Yes 7.7%; Maybe Not 1.1%) (Figure 6B).

Taken together, the findings indicate that ISS is characterized by high user satisfaction and good usability.

Safety and Device performance
The safety and tolerability of ISS were assessed based on adverse events reported by participants during the survey period. A total of 100 patients provided safety data. The most commonly reported adverse events were nasal dryness, noted by 15 patients (15.0%), and nasal irritation or discomfort, reported by 12 patients (12.0%; 11 events reported as adverse events and one registered under the category device malfunction), of whom one case occurred in a pediatric patient. Headache was recorded in 3 patients (3.0%). Two patients (2.0%) reported epistaxis, and 3 patients (3.0%) described other symptoms, including itching (n = 1) and pain (n = 2) (Figure 7A). The majority of adverse events were mild in nature, and no serious adverse events were reported during the study period.

Device performance was also assessed, including any technical issues reported during use. In total, six device malfunctions were recorded among the 98 respondents. One event (reported as nasal irritation) was classified and analyzed as an adverse event (see section above) and was therefore not included in the device performance analysis. Therefore, five device malfunctions (5.1%) were considered (Figure 7B), which included difficulty with spraying (n =2), spraying fault (n=1) and mechanical damage to the device (n = 1), while no description was provided for one reported malfunction (Figure 7C).

These findings support the continued use of ISS as a well-tolerated option in the management of sinonasal conditions.