Introduction
Functional endoscopic sinus surgery (FESS) is the treatment of choice in, and improves quality of life (QoL) for, patients with chronic rhinosinusitis refractory to medical treatment. The aims of surgery are to improve the QoL in patients, achieve patency of the sinus drainage pathways and reduce inflammation.Reference Stammberger and Posawetz1,Reference Timperley, Schlosser and Harvey2
There is however variation in the surgical management of patients with frontal sinus disease, and frontal sinusotomy is not always performed. The classification of frontal sinus surgery was first described by Wolfgang Draf in 1991, and these principles remain largely unchanged today.Reference Draf3
Accessing the frontal sinus can be technically challenging because of variable anatomy and the proximity of nearby critical structures, such as the orbit, skull-base and olfactory fossa. Furthermore, there are concerns that post-operative scarring may later lead to iatrogenic frontal sinus symptoms. It has been shown endoscopically that following frontal sinus surgery, most patients demonstrate lasting frontal sinus patency and that their QoL is improved.Reference DeConde and Smith4 This QoL improvement however has been measured using generic or disease-specific questionnaires (e.g. Sino-Nasal Outcome Test (SNOT)-22, the 36-Item Short Form survey, Nasal Obstruction Symptom Evaluation score or EuroQol 5 Dimension which is a questionnaire measuring health-related quality of life)Reference Klonaris, Doulaptsi, Karatzanis, Velegrakis, Milioni and Prokopakis5 that target paranasal sinus disease as a whole. It is therefore difficult to isolate the specific symptomatology attributed to the frontal sinus in isolation, especially as it is rare to operate on this sinus alone. Traditionally, frontal sinus disease has been considered to be associated with the symptoms of frontal pain. Objectively, however, the diagnosis of frontal sinus disease is largely dependent on the radiological findings as it is usually quite difficult to visualise the frontal sinus endoscopically in the out-patient clinic, unless previous surgery has been performed making the endoscopic visibility of this difficult area less challenging. But is frontal pain truly a symptom of frontal sinus disease and is there a correlation between the frontal pain and the objective findings of frontal sinus disease?
This study aims to further understand the presentation of frontal sinus disease with two objectives. First, it aims to explore whether, in the context of chronic rhinosinusitis, there is an association between frontal pain and radiological frontal sinus disease. Second, it aims to determine whether there is a correlation between frontal pain and the degree of severity of chronic rhinosinusitis. The latter was assessed by objective endoscopic evaluation using the validated modified Lund–Kennedy score,Reference Psaltis, Li, Vaezeafshar, Cho and Hwang6 as well as by validated QoL questionnaires, such as SNOT-22 and Nasal Obstruction Symptom Evaluation score. Additionally, the relationship between the specific frontal pain score and the more generalised facial pain or pressure score (as elucidated from the SNOT-22 questionnaire) was also evaluated to identify whether frontal pain can occur in isolation or whether it is a component of a generalised facial pain.
Materials and methods
This observational study analysed prospectively collected patient data of 51 consecutive patients with objective evidence of chronic rhinosinusitis who were undergoing endoscopic sinus surgery after failing to respond to medical treatment.
The exclusion criteria for the study were: (1) patients with unilateral sinus disease; (2) patients with proven non-inflammatory sinus disease; (3) patients with secondary chronic sinusitis (sinusitis secondary to autoimmune disorders, mucociliary disorders, neoplastic disorders, and so on); (4) patients with hypoplastic or aplastic frontal sinuses; and (5) patients presenting with orbital or intracranial complications of sinusitis.
Patients were classified following endoscopic examination into three groups: (1) sin polyps (no evidence of nasal polys); (2) ethmoid polyps (limited nasal polyps in ethmoid sinuses but not extending into the nasal cavities); and (3) with polyps – diffuse evidence of nasal polyps in nasal cavities.
All patients were asked to: rank their individual frontal pain score on a numerical rating scale from 0 to 10 and complete the SNOT 22Reference Hopkins, Gillett, Slack, Lund and Browne7 and Nasal Obstruction Symptom Evaluation score questionnaires.Reference Stewart, Witsell, Smith, Weaver, Yueh and Hannley8 The facial pain or pressure score from the SNOT-22 was extracted and recorded separately for each patient. A frontal sinus opacification score was calculated using the Lund–Mackay scoring system, and the modified Lund–Kennedy score was also completed for each patient. A brief explanation of each of these scoring systems is outlined below (Table 1). Patient demographic data were obtained from medical records.
Scoring systems used in patient assessment
*SNOT-22 can be categorised into mild (8–20), moderate (21–50) and severe (>50)Reference Toma and Hopkins9. SNOT = Sino-Nasal Outcome Test; NOSE = Nasal Obstruction Symptom Evaluation score
Statistical analysis
Data were collected using Microsoft Excel® 2016 and the statistical analyses were performed using Social Science Statistics (https://www.socscistatistics.com) The relationship between different patient groups was calculated using analysis of variance (ANOVA), and the correlation between the separate scores (frontal pain, facial pain or pressure, Nasal Obstruction Symptom Evaluation score, frontal sinus opacification and Lund–Mackay score) were calculated using Pearson's correlation coefficient.
Ethical approval
Ethical approval was deemed not necessary for this study as the questionnaires completed by the patients (SNOT-22 and Nasal Obstruction Symptom Evaluation score), the enquiry about the severity of the patients’ symptoms (including frontal pain), the endoscopic and radiological assessment and the surgery performed did not vary from the authors’ normal practice when dealing with patients presenting with chronic rhinosinusitis.
Results
A total of 51 patients were included in the study, with 34 males and 17 females. Age ranged from 15–80 years (mean, 50 years; median, 48 years). The disease characteristics and frontal pain scores for the participants are summarised in Table 2.
Disease characteristics and frontal pain scores of study population by chronic rhinosinusitis type
Frontal pain scores ranged from 0–8 (mean, 2.7; median, 3; mode, 0), and facial pain or pressure scores ranged from 0–5. A positive correlation was observed between the two. For both parameters, scores were highest in the sin polyps group, although this did not reach statistical significance at p < 0.05 (ANOVA, frontal pain: F = 2.65, p = 0.08; facial pain or pressure: F = 3.15, p = 0.05).
The SNOT-22 scores ranged from 8–107 with a mean SNOT-22 score of 50. A total of 12 per cent of participants scored within the ‘mild’ category, and 44 per cent of participants scored within each of ‘moderate’ and ‘severe'categoriesReference Toma and Hopkins9 (Figure 1). A weak positive correlation was demonstrated between frontal pain scores and SNOT-22 scores (R = 0.2996, p = 0.04). This correlation was stronger between pain or pressure scores and SNOT-22 scores (R = 0.6159, p = <0.01).
Sino-Nasal Outcome Test-22 scores by severity. Mild 8–20, moderate 21–50, severe >50.
No significant correlation was found between frontal pain scores and Nasal Obstruction Symptom Evaluation score (R = 0.01, p = 0.96), frontal sinus opacification scores (R = −0.2683, p = 0.05725) or modified Lund–Kennedy scores (R = −0.1685, p = 0.24). A summary of each of the outcome measures is outlined in Table 3.
Summary of outcome measures
IQR = interquartile range; SNOT = Sino-Nasal Outcome Test; NOSE = Nasal Obstruction Symptom Evaluation score
Discussion
Surgical management of the frontal sinus is associated with increased morbidity, higher re-stenosis rates and more treatment failure compared with the other paranasal sinuses.Reference Abuzeid, Mace, Costa, Rudmik, Soler and Kim10 The decision to operate on the frontal sinus and the extent of surgery must therefore balance the expected symptomatic improvement against these risks. It is therefore crucial to understand the role of frontal pain in frontal sinus symptomatology.
Previous work into the extent of frontal sinus surgery has demonstrated improved outcomes following Draf II and Draf III procedures.Reference DeConde and Smith4,Reference Abuzeid, Vakil, Lin, Fastenberg, Akbar and Fried11,Reference Orlandi, Kingdom, Smith, Bleier, DeConde and Luong12, However, very few high-quality comparative studies exist. In 2016, Abuzeid et al. compared the outcomes of Draf I surgery with more extensive Draf II and Draf III surgery in a multi-centre prospective study. They showed that there was a comparable improvement in SNOT-22 scores between the groups and advocated that ethmoidectomy alone may be effective in the treatment of chronic frontal sinusitis in certain sub-groups.Reference Abuzeid, Mace, Costa, Rudmik, Soler and Kim10
In 2020, Georgalas et al. conducted a 5-year retrospective review of 99 patients who had undergone either Draf II or Draf III procedures. They demonstrated that both groups achieved a similar end-point QoL, although the Draf III group started from a significantly lower baseline. As the aim of all surgery is to improve symptoms while minimising risk, there will be much interest if less extensive procedures can be shown to deliver equivalent outcomes.
In the context of chronic rhinosinusitis involving multiple sinuses and not responding to medical treatment, sinus surgery is usually indicated. Few surgeons in such a scenario will argue against performing a maxillary antrostomy if the maxillary sinus is involved with disease in the pre-operative computed tomography (CT) scan, even if the patient does not suffer from symptoms considered to be specific to the maxillary sinus, like pain in the cheek. However, a significant proportion of surgeons will choose not to perform a frontal sinusotomy for the same patient even when the frontal sinus is involved with disease in the pre-operative scan, unless the patient complains of symptoms specific to the frontal sinus. This discrepancy in decision making is likely to be related to the fact that frontal sinus surgery is more challenging than any other sinus surgery, rather than an actual difference in the pathology between the maxillary and the frontal sinuses, which can justify treating them in different ways. The big question here is: what are the specific symptoms for frontal sinus disease?
The dilemma remains that, apart from cases of frontal sinusitis presenting by orbital or cranial complications, we have no clear understanding of the symptoms related in particular to this sinus. This makes the planning of the extent of the surgery required for the frontal sinus, if any, more challenging. More high-level evidence is required to guide surgical decision-making and better understand the specific symptoms of chronic frontal sinusitis.
It is often considered that frontal pain or headache is the most prevalent symptom of frontal sinus disease,Reference Friedman and Rosenblum13 especially in cases when disease is limited to the frontal sinus alone.Reference Kountakis, Senior and Draf14 However, frontal headache is not listed in the EPOS 2020 diagnostic criteria for chronic rhinosinusitisReference Fokkens, Lund, Hopkins, Hellings, Kern and Reitsma15 and the International Headache Society believe that true frontal headache in the context of chronic pansinusitis is relatively rare.Reference Levine, Setzen, Cady, Dodick, Schreiber and Eross16 Furthermore, the SNOT-22 questionnaire, the most commonly used QoL questionnaire in chronic rhinosinusitis, does not specifically ask about frontal pain or headache.
This study aimed to explore the symptom of self-reported frontal pain in patients with proven chronic sinusitis and determine its utility as a specific marker for chronic frontal sinusitis. Using the SNOT-22 questionnaire, we demonstrated a moderate correlation with ‘facial pain or pressure’, a more commonly used diagnostic symptom for chronic rhinosinusitis and with a weak correlation between frontal pain and QoL. We observed no correlation with nasal obstruction or endoscopic findings, as measured by modified Lund–Kennedy scores or radiological frontal sinus opacification, indicating that frontal pain does not correlate with the objective evidence of frontal sinus disease. We therefore believe that the presence or absence of frontal pain should not be a factor when making a decision about operating on the frontal sinus.
Although there has been significant work in understanding the relationship between endoscopic, radiological and clinical outcomes in chronic rhinosinusitis, to our knowledge there have been very few studies looking specifically at frontal pain in the context of frontal sinusitis.
In this study, we demonstrated that in general this patient group reported low frontal pain scores and also low facial pain or pressure scores. Despite this, the majority of patients described moderate to severe effects on QoL, and both parameters were shown to correlate with SNOT-22 scores. The strength of this correlation, and other confounders, however, must be considered, and it therefore remains uncertain whether or not frontal pain is a significant marker of QoL in chronic rhinosinusitis. Testing with both pre- and post-operative questionnaires would improve validity and demonstrate the potential impact of surgical intervention on QoL.
Numerous previous studies have reported that there is no correlation between CT findings and the severity of patient-reported symptoms in chronic rhinosinusitis.Reference Hopkins, Browne, Slack, Lund and Brown17–Reference Bhattacharyya19 Although our own findings also demonstrate this, the only other study to examine the relationship between frontal pain and radiological assessment of the frontal sinus does report an association. This study, by DelGaudio et al.,Reference DelGaudio, Wise and Wise20 observed a study population of 207 patients and found that in non-mucocele chronic rhinosinusitis patients (n = 170), those with mild to moderate mucosal thickening on CT exhibited a greater degree of frontal pain (64 per cent) compared with those with complete opacification (37 per cent) or minimal thickening (43 per cent). They attribute this to an increased pressure differential across the sinus resulting from poor ventilation. In this study, they also observed that patients with nasal polyps are significantly less likely to present with frontal pain than patients without polyps or patients with frontal mucoceles. This is consistent with research in the wider context of chronic rhinosinusitis, where it has been shown that facial pain is less common in patients with nasal polyposis than those without.Reference Eweiss, Lund, Barlow and Rose21
In our study, although a similar trend was demonstrated regarding the sin polyps and with polyps groups, this did not reach clinical significance (p = 0.08). Possible explanations for the variations between the studies are small patient numbers in the current study and different study design. DelGaudio et al. documented the presence or absence of frontal pain retrospectively from patient records and classified the CT findings into three groups, whereas in the current prospective study, patients were asked to rank their frontal pain on a numerical rating scale, and CT scans were also scored on a point system. This difference in numerical rather than categorical input data may have accounted for more nuances in the statistical calculation; however, further work is clearly required. To our knowledge, this is the only study in which patients with frontal sinusitis have been asked to grade the extent of their frontal pain.
Numerical Rating Scales are a validated measure of pain in chronic disease with high test–retest reliability.22 An 11-point scale from 0 to 10 is most commonly used and is often categorised into: no pain = 0, mild pain = 1–3, moderate pain = 4–6 and severe pain = 7–10; however, this criterion has not been specifically validated for use in chronic rhinosinusitis and was not given to patients. Nonetheless, this study suggests that patients with chronic frontal sinusitis exhibit low frontal pain scores. This is in keeping with the consensus that the majority of patients with chronic frontal sinusitis will not complain of headache..Reference Seiden and Martin23 This is important in the wider context of frontal pain management as 88 per cent of patients reporting sinus headache meet the International Headache Society diagnostic criteria for migraine,Reference Schreiber, Hutchinson, Webster, Ames, Richardson and Powers24 yet there is a high prevalence of missed diagnosis because of the overlapping symptoms of headache, nasal congestion, facial pressure or pain and rhinorrhoea.Reference Straburzyński, Gryglas-Dworak, Nowaczewska, Brożek-Mądry and Martelletti25,Reference Eross, Dodick and Eross26 To complicate things further, chronic rhinosinusitis and migraine commonly co-exist,Reference De Corso, Kar, Cantone, Lucidi, Settimi and Mele27 and in a cohort study of 30 000 individuals Aaseth et al. showed that patients with chronic rhinosinusitis had a nine-fold increased risk of having chronic headache.Reference Aaseth, Grande, Kvaerner, Lundqvist and Russell28 Caution must therefore be taken when treating patients with frontal pain and sinusitis as a significant proportion of patients undergoing endoscopic sinus surgery describe persistent pain post-operatively.Reference De Corso, Kar, Cantone, Lucidi, Settimi and Mele27,Reference Jones and Cooney29 To aid in this diagnostic challenge, Wu et al. have proposed analysis of SNOT-22 score patterns and shown that patients with non-sinogenic headaches demonstrate higher scores in the ear, facial and psychological dysfunction questions than patients with chronic rhinosinusitis.Reference Wu, Gray, Holbrook, BuSaba and Bleier30
Limitations
The limitation of the current study is its small sample size. It is possible that in a higher-powered study with a larger cohort and association between pain and disease type (sin polyps, ethmoid polyps, with polyps) may have reached significance. It would also have been useful to have access to post-operative scores for each of the testing parameters to assess the impact of intervention, although of course this was not in the study aims.
One patient did not complete a SNOT-22 questionnaire and was therefore excluded from analysis of facial pain or pressure and SNOT-22. It must also be noted that patients were asked to complete these questionnaires when assessed pre-operatively either in the out-patient clinic or on the day of surgery, whereas CT scans were often performed several months prior to this. This however is common in this type of study, and it is thought that radiological findings remain largely constant over time.
Conclusion
This study evaluated a sample of 51 patients undergoing endoscopic sinus surgery with objective evidence of chronic sinusitis. We found that in general, the frontal pain score among these patients is low and demonstrated no correlation between frontal pain and the extent of frontal sinus disease radiologically or frontal pain and the severity of overall sinus disease endoscopically. While a significant correlation was noted between higher frontal pain scores and worse QoL (as measured by the SNOT-22 questionnaire), this association requires further scrutiny and adjustment for confounding variables.
• It is difficult to understand the specific symptomatology of frontal sinus involvement in chronic rhinosinusitis as it is rare to operate on the frontal sinus in isolation
• This study explored the relationship between self-reported frontal pain, disease severity and the extent of radiological and endoscopic frontal sinus disease
• Findings show that frontal pain is minimal in chronic rhinosinusitis patients and shows no correlation with the extent of frontal sinus disease radiologically or overall sinus disease endoscopically
• Non-sinogenic headache should be considered in patients complaining of frontal pain
• This study concludes that frontal pain is not a sensitive nor specific marker of frontal sinus disease and should not be used in the decision-making process for the extent of endoscopic frontal sinus surgery
This study therefore does not support the use of frontal pain as a sensitive or specific marker of frontal sinus disease, and therefore cannot recommend its use in the decision-making process for the extent of endoscopic frontal sinus surgery. Patients presenting with this symptom should be properly counselled to exclude non-sinogenic headache and ensure they have realistic expectations regarding the improvement of their frontal pain post-operatively.Reference Eweiss, Lund, Barlow and Rose21
Competing interests
None declared
