Abstract
Chronic rhinosinusitis a very common disease characterized by inflammation of the mucosa of the paranasal sinuses. Nasal endoscopy and computed tomography (CT) scans are successfully used as diagnostic modalities of nose and paranasal sinus diseases. CT scan has been traditionally considered as the gold standard for diagnosing Chronic rhinosinusitis. But high cost, radiation exposure and high rates of false positivity are important drawbacks. However, nasal endoscopy as an OPD tool helps in early categorization of patients for further evaluation by imaging. This is a cost cutting as well as time saving option.
To compare nasal endoscopy and CT scan with respect to prediction of intrasinus involvement.
To evaluate the role of nasal endoscopy as an effective alternative to CT-scan in diagnosing chronic rhinosinusitis.
82 clinically diagnosed cases of chronic rhinosinusitis underwent CT scan and were advised to undergo diagnostic endoscopy. Both the modalities were compared for the diagnosis of chronic rhinosinusitis with focus on anatomic variations and the pathological findings in the nose and paranasal sinuses, and their correlation, specificity, sensitivity, positive predictive value and negative predictive values were calculated. The association between diagnostic endoscopy and CT was calculated using χ2 test. Pearson χ2 value: 8.173, P value = 0.004 (<0.05) i.e. significant. The sensitivity and specificity of nasal endoscopy was calculated with respect to diagnosing chronic rhinosinusitis in comparison to CT-scan. The results were: sensitivity was 78.08% (95% CI 66.57–86.58%), specificity was 66.67% (95% CI 30.91–90.95%) while the positive predictive value: 95% and the negative predictive value was 27.27%. CT scan is considered to be the gold standard for sinonasal imaging. Endoscopy can predict the intrasinus involvement in rhinosinusitis thereby reducing overdone CT-scans.
Keywords: Rhinosinusitis, Endoscopy, CT Scan, Diagnosis, CRS, Staging
Introduction
Chronic rhinosinusitis (CRS) is a common global disease which hampers the overall quality of life. ‘Rhinosinusitis’ is the preferred term for the inflammation of the nose and paranasal sinuses as the inflammation of sinuses (called ‘sinusitis’ erstwhile) nearly always also involves the nose [1–3].
Osteomeatal complex (OMC) is the main focus of interest for rhinologists and radiologists, it is composed of narrow channels and openings of various sinuses. These become blocked by anatomical variation, mucosal swelling, secretions, polyps and other such factors. Obstruction to the OMC hampers sinus drainage and result in stasis and inflammation followed by secondary infection producing symptoms [1, 4, 5].
The anatomical and structural variations and the subtle mucosal changes of middle meatus and osteomeatal complex are effectively identified by nasal endoscopy. These anatomical variations and mucosal changes cause drainage block leading to chronic rhinosinusitis [6, 7].
CT scan has been accepted as the gold standard pre-requisite while considering for endoscopic sinus surgery, in suspected complications of sinusitis and in neoplasms of the nose and paranasal sinuses. CRS and its association with the symptoms score have been evaluated by a number of studies [2].
Multiple studies in past has been attempted to compare the diagnostic utility of CT-scan and nasal endoscopy in CRS but this has been a matter of debate because of high variability of results. However in present times both CT-scan and nasal endoscopy are called for evaluation of patients of suspected chronic rhinosinusitis. CT-scan has its own disadvantages because of risk of radiation exposure, high false positivity and high costs [2, 6, 7]. Thus it is a point of discussion whether endoscopy can replace CT-scan in effectively diagnosing chronic rhinosinusitis.
Materials and Methods
The present study was conducted in the Department of Otorhinolaryngology, of a tertiary teaching hospital of North India from, January 2014 to July 2015. Sample size of 82 patients were included in the study with informed consent and clearance of ethical committee.
The patients were clinically diagnosed as a probable case of chronic rhinosinusitis and then subjected to the investigative procedures: Diagnostic nasal endoscopy and CT scan. The endoscopy was done before the CT scan to avoid any observer bias. The investigations were done on the prior to initiation of any therapy. The selection of cases was based on a detailed clinical history of rhinosinusitis with duration of symptoms more than 12 weeks.
Criteria for Selection of Cases
Inclusion Criteria
Patient attending outpatient department (OPD) or admitted patients who were clinically diagnosed as Chronic rhinosinusitis.
Only those cases were registered, who gave full informed consent for the study.
Adults of all age groups and both sexes were included.
Exclusion Criteria
Patients with rhinosinusitis less than 12 weeks duration.
Patients with allergic rhinitis.
Patients with history of previous sinonasal surgeries.
Patients less than 18 years age.
The diagnosis of chronic rhinosinusitis is done by following the criteria based on subjective symptoms as defined by American Academy of Otolaryngology-Head and neck surgery (AAO-HNS) task force criteria and as suggested by the European Position Paper on Rhinosinusitis and Nasal Polyps (Fokkens et al., EPOS 2007 and 2012), from an epidemiological standpoint, chronic rhinosinusitis (with or without nasal polyps) in adults is defined as: presence of two or more symptoms one of which should be either nasal blockage/obstruction/congestion or nasal discharge (anterior/posterior nasal drip): ± facial pain/pressure; ± reduction/loss of smell; and symptoms must be present for more than 12 weeks [2, 6–9].
Rigid nasal endoscopy was performed on all subjects under local anesthesia with topical application of 4% Lidocaine Hydrochloride and using 0 and 30 degree 4 mm diameter rigid nasal endoscope in accordance with by SAHP Task Force criteria for defining adult CRS [7].
The endoscopic findings were interpreted using Lund–Kennedy grading system to assess the following parameters: nasal mucosal edema (0: absent, 1: minimal, 2: gross), presence of secretion (0: absent, 1: thin, 2: purulent) and presence of polyps (0: absent, 1: present in meatus, 2: present in nasal cavity but not obstructing airway, 3: nasal cavity with obstruction of airway) [2, 10].
The patients were subjected to CT-scan in a 64-slice CT scan machine and 1.5 mm thin cuts were obtained in coronal, sagittal and axial planes, both in bone-window and soft tissue window settings. CT scan was evaluated using the well recognized Lund MacKay System with the right or left sinuses respectively divided into six portions, including maxillary sinus, anterior ethmoid sinuses, posterior ethmoid sinuses, sphenoid sinus, frontal sinus, and ostiomeatal complex. The severity of sinus mucosal inflammation or fluid accumulation was scored as 0 (complete lucency), 1 (partial lucency) or 2 (complete opacity) [2, 11]. Endoscopy was grouped as ‘negative’ (Endoscopy negative) if Lund Kennedy score was 0. Patients who obtained any other score were grouped as abnormal and ‘positive’ (Endoscopy positive). And a zero score in Lund MacKay System was grouped ‘negative’ (CT negative) and scores above 0 were classified as ‘positive’ (CT positive).
All the assessments of CT and endoscopy were performed by different assessors who were blinded to each others’ results to avoid bias. The anatomical findings were assessed for every patient.
The data was analyzed using the opensource software ‘Statistical Product and Service Solutions’ (SPSS) version 16 and online program Graphpad. Sensitivity, specificity and likelihood ratios (LR) were estimated for endoscopic diagnosis of CRS using CT scan as gold standard.
Results
Only adults were included in the study. The mean age (±SEM) of presentation was 34.11 (±1.42) years. Males were predominating the study group with 62.2%.
All the patients were initially examined clinically in the OPD along with proper history and provisionally diagnosed as cases of chronic rhinosinusitis. Major presenting complaints in our study were nasal blockage (93.9%), nasal discharge (76.8%) and facial pain (61%) with headache (42.68%) and anosmia (20.7%) less commonly encountered.
The diagnostic findings of nasal endoscopy and CT scan are compared in detail in the Table 1. The parameters such as deviated nasal septum, septal spur and inferior turbinate hypertrophy were comparable in both endoscopy and CT scan.
Table 1.
Comparison of CT scan and endoscopy findings
Parameters | Endoscopic seen | CT scan reported | ||
---|---|---|---|---|
No. | % | No. | % | |
DNS | 70 | 85.36% | 76 | 92.68% |
Septal spur | 32 | 39.0% | 33 | 40.24% |
Mass or polyp nasal cavity | 4 | 4.8% | 9 | 10.97% |
Inferior turbinate hypertrophy | 55 | 67.07% | 47 | 57.31% |
Concha bullosa | 8 | 9.75% | 25 | 30.48% |
Maxillary sinus haziness | – | – | 58 | 70.73% |
Ethmoidal sinus haziness | – | – | 48 | 58.53% |
Sphenoidal sinus haziness | – | – | 30 | 36.58% |
Frontal sinus haziness | – | – | 22 | 26.82% |
Blocked hiatus semilunaris | 22 | 26.82% | 28 | 34.14% |
Frontal recess block | – | – | 10 | 12.1% |
Sphenoethmoid recess block | 16 | 19.51% | 17 | 20.73% |
Polyp | 4 | 4.8% | 9 | 10.97% |
Onodi cells | – | – | 9 | 10.97% |
Haller cells | – | – | 8 | 9.75% |
Agger nasi cells | – | – | 22 | 26.8% |
Bent uncinate process | 5 | 6.09% | 1 | 1.21% |
Paradoxical middle turbinate | 3 | 3.65% | 12 | 14.63% |
Discharge in middle meatus | 72 | 87.80% | – | – |
While the findings such as concha bullosa and bent uncinate varied greatly. Certain structures like onodi cells, haller cells and agger nasi cells could not be visualized during diagnostic endoscopy.
Opacification or haziness of sinuses could only be seen in CT scan and we found out that maxillary and ethmoidal sinuses were involved maximally.
We found the following overall correlation (Table 2) on categorizing patients as CT and Endoscopy; positive and negative respectively based on the Lund–Mackay and Lund–Kennedy staging systems.
Table 2.
Final results of study group (n = 82)
CT scan positive | CT scan negative | Total | |
---|---|---|---|
Endoscopy positive | 57 | 3 | 60 |
Endoscopy negative | 16 | 6 | 22 |
Total | 73 | 9 | 82 |
The sensitivity of endoscopy was 78.08% (95% Confidence interval: 66.57–86.58%) and the specificity was 66.67% (95% Confidence interval: 30.91–90.95%).
The Likelihood ratio (LR) for a positive endoscopy to diagnose CRS is 2.29 and the Likelihood ratio for a negative test to rule out CRS was 0.33. For a pretest probability of less than 50% the post test probability is 24% which means that endoscopy is helpful in ruling out CRS if it does not confirm the diagnosis. Similarly with a pretest probability of 90% and with a positive endoscopy one can effectively diagnose CRS as the post test probability for positive test is 95%.
The Pearson χ2 value was 8.173 with P value = 0.004 (<0.05) i.e. Significant.
Discussion
Chronic rhinosinusitis is quite a common disease, as in an European study the GA2LEN study found out a high prevalence rate of about 10.9% population [12]. In a nationwide survey in Korea [13], the overall prevalence of CRS, defined as the presence of nasal obstruction and nasal discharge lasting more than 3 months together with the endoscopic objective findings such as discolored nasal drainage in the nasal passage or nasal polyps, was 6.95% [13].
CT scan is considered as the gold standard in diagnosing rhinosinusitis while nasal endoscopy is performed to look for anatomic variations and mucosal changes [14–17]. The majority of objective data used to diagnose CRS are either provided by a CT scan or endoscopic evaluation of nose, so any prospective clinical trial should have documentary or photographic records of these as per recommendations [14, 15, 18].
In our study age of patients varied among all adult age groups with the maximum number of patients in 18–30 years category. The study conducted by Kirtane et al. (1991) the age ranged from 16 to 52 years with the maximum patients in the third decade [19, 20]. In our study the majority of the patients (48.8%) were in 18–30 years.
Nasal endoscopy and CT scan used in combination can accurately identify even minute changes in osteomeatal complex [3, 21]. On the endoscopy, in addition to gross findings such as pathologic discharge, subtle evidence of disease in the osteomeatal area may be identified.
Hiatus semilunaris, infundibulum, frontal recess and sphenoethmoid recess are the key areas where all major sinuses drain, it can be inferred that diagnostic endoscopy can be definitely used as the sensitive tool towards diagnosing the infection in the adjacent sinuses [22].
There were significant percentage of various parameters that could not be visualized at the endoscopy because in some of the cases it was impossible to pass the endoscope beyond certain point due to severe anatomical abnormalities like a severely deviated nasal septum, paradoxical middle turbinate, or a concha bullosa. CT scan definitely proved to be very helpful in these cases.
The National Radiation Protection Board (NRPB) has suggested that CT contributes to the increased collective dose from medical radiology. The overutilization and cost are other two limiting factors for CT-scan [2, 23]. Thus justifying our study of using endoscopy as an alternative to CT scan.
Comparison of results of the present study with the past studies evaluating the role of Endoscopy in the diagnosis of Chronic Rhinosinusitis (Table 3).
Table 3.
Comparison of results, outcomes and conclusions of previous studies
Study | Year | Statistical measure | Sample size |
---|---|---|---|
Benninger [24] | 1997 | Proportion (11%) | 100 |
Rosbe [25] | 1998 | Proportion (91%) | 92 |
Hughes [26] | 1998 | Sensitivity (84%), specificity (92%) | 140 |
Stankiewicz [27] | 2002 | Sensitivity (46%), specificity (86%), PPV (74%), NPV (64%) | 78 |
Bhattacharya [28] | 2010 | PPV (66%), NPV (70.3%), OR (4.6) | 202 |
Ryan [29] | 2011 | PPV (92.5%) NPV (45.5%) (LM score ≥ 1) | 51 |
Ferguson [30] | 2012 | Sensitivity (24%), specificity (100%) | 125 |
Kolethekkat [2] | 2013 | Sensitivity (91%), specificity (44%) | 75 |
Present study | 2014–15 |
Sensitivity: 78.08% Specificity: 66.67% PPV: 95% NPV: 27.27% |
82 |
Diagnostic endoscopy is quite sensitive and specific tool to diagnose the disease and to note the pathology in the areas that are inaccessible for visualization by routine anterior rhinoscopy. The diagnostic endoscopic findings correlate well with the computed tomographic findings.
The statistical results of our study suggest that the presence of mucosal changes, mucopurulent/purulent discharge or polypoidal changes can effectively point the diagnosis towards chronic rhinosinusitis obviating the need of routine CT-scanning at least at the first instance. However, a normal endoscopy does not completely rule out chronic rhinosinusitis, and such patients if planned for surgery or not benefitted with conservative treatment need further evaluation and in these cases CT-scanning is recommended.
Conclusion
Endoscopy can effectively be the initial diagnostic modality to suggest rhinosinusitis and the baseline pictures can serve as documentation to see for treatment outcomes in follow up visits. Endoscopy is helpful in ruling out CRS if it does not confirm the diagnosis. Endoscopy can support or refute CT scan findings thereby reducing over-diagnosis of Chronic rhinosinusitis. Finally CT scan is still the gold standard modality for chronic rhinosinusitis and whenever a surgery is planned, as it serves both for diagnosis of the disease status and also as an anatomical road map.
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity.
Compliance with Ethical Standards
Conflict of interest
There are no conflicts of interest.
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