Synopsis
Grading systems to clinically evaluate nasal obstruction are myriad but lack any consensus or standardisation. In addition, some of these demonstrate no correlation to nasal airflow as demonstrated by Camacho et al. who compared NOSE, VAS and inferior turbinate size [
1]. Visualisation of the anatomical INV boundaries remains the key to evaluate these patients.
Our internal nasal valve grading system is a simple and reproducible grading system to objectively assess nasal obstruction. This study demonstrates excellent inter-rater and test–retest reliability (across a large number of observations), which is fundamental to the use of any grading system. This scoring tool is of value for the static component of INV dysfunction. These grades can therefore be affected by a multitude of pathologies such as septal deviation, turbinate hypertrophy, inferior displacement of the upper lateral cartilages or a narrowed pyriform aperture. Clinical acumen is still required to decide how best to achieve expansion of the nasal airway to improve the patient’s symptoms. In addition, the dynamic component of the INV must also be assessed preoperatively. In this study, we selected only primary surgical candidates with no evidence of dynamic collapse. We also ensured that there was little reversibility in nasal airflows post-decongestion to exclude or minimise the impact of mucosal disease. This grading system also serves as an operative guide, in that, we aim for a grade 0 view at the end of the surgery, and thus, for example, in addition to realigning the septum, spreader graft insertion may be necessary to ensure an optimal view of middle turbinate and hence optimise nasal airflow.
This study also demonstrates significant improvements in INV grading postoperatively alongside with other subjective and objective outcome measures. These data will be useful to highlight the efficacy of septorhinoplasty surgery, particularly in view of increasing commissioning restrictions.
In this series, visual analogue scores appear to correlate with unilateral NIPFs. Visual analogue score is often thought to represent the best outcome measure for identifying nasal obstruction [
10]. This aids in the validation of unilateral NIPF as an essential routine measure and may represent the best objective marker of nasal obstruction. The moderate correlation between the INV grading system and unilateral NIPF demonstrates the benefits of the grading system and justifies its use as a standard of care.
A previous study in our centre demonstrated postoperative improvement in NIPFs following septorhinoplasty although there was no significant correlation with SNOT scores [
4]. In this study, we have shown that unilateral NIPFs do correspond with subjective unilateral and bilateral blockage. This study suggests that VAS, NIPFs and INV grading are the most useful markers. Unsurprisingly, there was good correlation between NOSE and VAS scores. There was no significant correlation with SNOT-23, most likely in view of its wider range of questions rather than focusing on nasal blockage symptoms.
Prospective data collection in the form of questionnaires, grading scales and objective data in the form of NIPFs are valuable at monitoring both medical and surgical interventions and serve as useful tools to monitor outcomes and identify trends. Interestingly, our study found that following surgery there was an improvement in all of the outcomes recorded. It is also beneficial for patients to see how their scores have improved following intervention. Ideally a consensus should be reached for a minimum dataset, much like thyroid surgery, to be recorded by all surgeons to allow comparison of outcomes. This concept was particularly borne out following a recent questionnaire evaluating current ENT practice in measuring nasal obstruction [
11].
Strengths and limitations of the study
We have validated an objective, reliable and reproducible grading system for the static internal nasal valve. This is of clinical value in assessing patients appropriately with nasal obstruction. We have also shown that the INV can be surgically improved with resultant improvements in both subjective and objective outcome measures.
An additional strength of this grading system is its ability to augment the training of septorhinoplasty surgery amongst our juniors. It came to light that by instilling the concept of being able to visualise the middle turbinate bilaterally as an end marker of operative success, juniors found this grading system very valuable, although it is important to be aware of and assess for the role of mucosal disease in these patients alongside with the dynamic aspect of INV dysfunction.
The main limitation of this study is the reduced number of participants due to incomplete datasets and the subsequent limited power of the study. However, within our NHS limitations and given that, at least 112 INV gradings were made by three different observers of varying grades; there were sufficient data to ascertain our primary endpoint, the reliability and reproducibility of the grading system.
A further limitation of this study was that we did not incorporate an additional dynamic component to the grading system which would have evaluated internal valve collapse on deep inspiration. We decided against this as it proved challenging to measure with regards to explaining to the patient the force of deep inspiration required and also we were very conscious to keep this simple and easy to use in our busy clinical setting. In addition, controversy exists regarding the dynamic evaluation of nasal obstruction [
3‐
5]. While acoustic rhinometry may provide a static measure of the cross-sectional area across the INV, the placement of the probe itself splints the nasal airway and therefore invalidates measurement of the INV through this modality. By contrast, a recent study by Pendolino et al., has demonstrated reasonable correlation between unilateral NIPF and unilateral AAR—the gold standard in the measurement of nasal airway resistance [
12]. We therefore feel that unilateral NIPF represents a good measurement of nasal airflow.
Furthermore, recent publications question the concept of the INV angle and computational dynamics indicate that the shape of this region is variable, suggesting that assessment with anterior rhinoscopy or endoscopes is not sufficient [
2].