Nasal Septal Perforation Impairs Olfactory and Trigeminal Function

Nasal Septal Perforation: Unpacking Its Sensory Dimensions

Nasal septal perforations (NSP) are a familiar clinical challenge, typically presenting with nasal obstruction, crusting, and epistaxis that diminish patient quality of life [1]. While surgical procedures are well established for structural problems like septal deviation [2, 3], the functional consequences of a perforation, particularly on sensory perception, have been less clearly defined. The nasal cavity's complex anatomy is integral to both respiratory airflow and chemosensation, meaning structural defects can disrupt olfaction and trigeminal nerve input [4]. Although endoscopic techniques have advanced treatment for many sinonasal conditions, iatrogenic septal perforation remains a potential complication, highlighting the need to understand its full impact [5, 6]. A recent study now provides a more detailed map of these sensory deficits, linking them to specific anatomical and patient-specific factors [7].

Study Design and Patient Cohort

To clarify the relationship between nasal septal perforation (NSP) and sensory function, investigators in Barcelona conducted a cross-sectional study, a design that provides a snapshot of a population at a single point in time. The research, which collected data from 2017 to 2024 at two hospitals, aimed to evaluate the sense of smell in patients with NSP and identify factors linked to olfactory dysfunction. The study included a cohort of 123 patients with symptomatic NSP alongside a comparison group of 74 healthy controls. Among patients with a perforation, intranasal cocaine use was the most frequent etiology. For each participant, the researchers collected demographic and clinical data, including age, sex, comorbidities, and body mass index (BMI). Patient-reported symptoms were quantified using the Sinonasal Outcome Test (SNOT-22) and the Nasal Obstruction Symptom Evaluation for Perforation (NOSE-Perf) questionnaires. Olfactory function was assessed objectively using the Barcelona Smell Test 24 (BAST-24), supplemented by a subjective visual analogue scale (VAS). The perforation's physical characteristics, including its size and location, were precisely measured using both nasal endoscopy and sinus computed tomography scans.

Quantifying Olfactory and Trigeminal Deficits

The investigation confirmed that nasal septal perforation (NSP) has a significant impact on both the olfactory and trigeminal systems. Analysis of the 123 patients with NSP revealed that deficits in odor identification were particularly common, affecting 85 patients (69.1%). In contrast, difficulties with odor detection and odor memory were less frequent but still notable, each being observed in 26 patients (21.1%). These rates of dysfunction were all significantly different from those in the healthy control group, establishing a clear association between the presence of an NSP and impaired olfaction. The study also uncovered a concurrent loss of trigeminal function, which is responsible for sensations like coolness, tingling, or irritation from stimuli like menthol or ammonia. Among the patients who had olfactory dysfunction, 34% also showed impairment in trigeminal detection, and 51% had impairment in trigeminal identification. This dual sensory deficit suggests that NSP compromises not only the ability to smell but also the broader chemosensory experience that contributes to flavor perception and the detection of potentially hazardous airborne substances.

Factors Influencing Olfactory Identification

To isolate the factors most strongly associated with sensory loss, the researchers employed multivariate analysis, a statistical method that teases apart the influence of multiple variables. This analysis revealed that after correcting for the underlying cause of the perforation, significant differences in olfactory identification ability were linked to the NSP area and the patient's body mass index (BMI). Specifically, lower odor identification scores were associated with a larger perforation area and a higher BMI. The finding that this relationship was independent of etiology is important, as it suggests these physical and physiological factors have a direct influence on olfactory function, regardless of whether the perforation was caused by trauma, surgery, or cocaine use. The study also found that the objective test results aligned with patients' subjective experiences. A moderate correlation was observed between olfactory identification scores and patient-reported symptom severity on a visual analogue scale (VAS), as well as with specific items on the SNOT-22 (item 21) and NOSE-Perf (item 10) questionnaires. Furthermore, olfactory identification scores were significantly correlated with trigeminal scores, reinforcing the clinical observation that these two interconnected sensory systems are often affected together.

Clinical Implications for NSP Management

These findings provide clinicians with a more nuanced understanding of the functional consequences of nasal septal perforation (NSP), moving beyond the classic symptoms of obstruction and crusting. The study, which included 123 symptomatic patients, demonstrates that a substantial portion experience significant, measurable sensory deficits. The key clinical takeaway is that certain factors may signal a higher risk for these impairments. The data show that lower olfactory identification outcomes were associated with a larger NSP area and a higher body mass index (BMI), independent of the perforation's cause. This suggests that during patient evaluation, the presence of a large perforation or an elevated BMI should prompt the clinician to specifically inquire about changes in smell or taste. Given that 69.1% of NSP patients in this cohort had difficulty with odor identification, routine questioning about sensory symptoms is warranted. This information can improve patient counseling, help manage expectations for treatment outcomes, and guide decisions about whether a formal olfactory assessment is indicated, thereby enabling more comprehensive care for this patient population.

References

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