Evaluation of computed tomography (CT) findings in patients with symptomatic deviated nasal septum and their correlation with intraoperative findings

Aim To evaluate the computed tomography (CT) findings in patients having a symptomatic deviated nasal septum (DNS) and their comparison with intraoperative findings. Methods Cross-sectional, observational study done in the department of ENT and HNS at a tertiary care center, over a period of 16 months. Patients presenting with nasal obstruction as the chief complaint and findings of deviated nasal septum on anterior rhinoscopy without clinical features of chronic rhinosinusitis (CRS) were included in the pre-sent study. All patients underwent CT scans of paranasal sinuses (PNS) as per the govt. scheme for approval of surgery. Surgery was planned as per the indication based on history, clinical examination, and non-contrast CT scan PNS findings. The average duration from CT scan to surgery was 4.5 weeks. Results All 200 (100%) patients had DNS with inferior turbinate hypertrophy in 103 (52.5%), concha bullosa in 22 (11.0%), pneumatized superior turbinate in 6 (3.0%), and PMT (paradoxical middle turbinate) in 22 (11.0%). On comparing CT scan findings with intraoperative findings, it was found that maxillary sinus involvement had been seen in 28 (14.0%) patients on CT scan and only 8 (4.0%) patients intraoperatively. Similarly, CT scan involvement compared to and intraoperative involvement of anterior ethmoidal sinus was seen in 20 (10.0%) compared to 6 (3.0%) patients intraoperatively, posterior ethmoid in 12 (6.0%) compared to 3 (1.5%) frontal sinus in 4 (2.0%) compared to 1 (0.5%), sphenoid in 11 (5.5%) compared to 2 (1.0%), and osteomeatal complex (OMC) in 27 (13.5%) compared to 6 (3.0%) patients intraoperatively. Involvement of PMT, enlarged inferior, and concha bullosa was similar on CT scan and intraoperatively. Conclusion From this study, we concluded that a preoperative CT scan is a poor tool in predicting sinus disease in patients without clinical features of sinus disease and has a limited role in patients with symptomatic DNS. Insurance companies and government agencies should review their policies of ordering CT scans for approving septal surgeries.


Background
The nasal septum is divided into bony, cartilaginous, and membranous parts.Most of the deviations are present in the cartilaginous part followed by bony septal deviations and bony cartilaginous junction.DNS is a nasal disorder, where the septum is deviated from its normal straight, symmetrical, and midline position.DNS approximately affects 80% of people, most of them unknowingly [1,2].Septal deflections can be developmental or secondary to trauma.Trauma during birth can cause septal deviations which are evident only later in life when there is a more active growth phase of puberty.In some cases, trauma occurs in childhood and can be easily overlooked until it increases with age and growth [3,4].Nasal obstruction is the most common symptom of DNS.Patients with unilateral septal deviations may complain of nasal obstruction on the contralateral side mostly due to inferior turbinate enlargement or hypertrophy of inferior turbinate (HIT) a phenomenon called paradoxical nasal obstruction.Therefore, turbinate reduction surgery is often done along with septoplasty procedures [5][6][7][8][9].
Anterior rhinoscopy allows visualization of the septum, inferior turbinate, and nasal valve area.Diagnostic nasal endoscopy allows detailed anatomy of the entire nasal cavity in most cases except when there is obstruction by impacted DNS, massive turbinate hypertrophy, large mass lesions in the nasal cavity, and apprehensive/uncooperative patients.Some authors promote physical examination as the gold standard for diagnosis of symptomatic DNS and that CT scan has a limited role in this patient population [10].Non-contrast computed tomography (NCCT) is the preferred approach for assessing nose and paranasal sinus structure and inflammation [11].A preoperative CT scan in symptomatic DNS patients can examine the nasal structure and identify ancillary sinonasal disorders.However this approach is more expensive, exposes patients to hazardous radiation, and may assess septal deviation differently than a dynamic 3-D physical assessment.It is therefore necessary to examine indications for its appropriate use before septoplasty [12].When nasal endoscopy is limited by obstructive pathology or chronic rhinosinusitis, a preoperative CT is recommended.CT is not recommended for septoplasty candidate selection or insurance approval, according to the literature [10].Furthermore, soft tissue thickenings on CT scans without symptoms of sinus disease are not an indication for sinus surgery and most of these patients have normal or near normal sinuses on endoscopic sinus surgery when surgery was done after a few weeks following the CT scan.
This study was done to assess the CT scan results in patients having symptomatic DNS and compare those findings with intraoperative findings.

Setting of study
This research has been performed in the Department of ENT and HNS, in a tertiary care hospital for a duration of 16 months from January 2022 to April 2023.

Population
The population comprised of the patients attending the outpatient department of ENT and HNS.

Sample size
The sample size consisted of 200 patients who were admitted to the ENT and HNS department and fulfilled the criteria for sample selection.

Criteria for sample selection Inclusion criteria
• A patient presenting with nasal obstruction and diagnosed with DNS on anterior rhinoscopy.

Exclusion criteria
• Acute or chronic rhinosinusitis with or without nasal polyposis.• History of previous nasal surgery.
• Tumors involving the nose and PNS.

Tools and techniques
Patients presenting with nasal obstruction and findings of DNS on anterior rhinoscopy, who satisfy the inclusion criteria, were in the research.Detailed history has been taken including history of the symptoms, their time duration, aggravating and relieving factors, allergic history, medication history, and history of past nasal surgery.ENT examination was done including a nasal examination.External nasal examination and nasal cavity assessment have been done.Anterior rhinoscopy and nasal endoscopic findings were recorded for each patient.NCCT of PNS was ordered for each patient.Coronal and axial sections with a slice thickness of 1 mm were done to evaluate each patient to look for any inflammatory changes within the nose and paranasal sinuses, OMC pathologies, and turbinate hypertrophy.Any anatomical variations like concha bullosa, uncinate process abnormalities, and other anatomical variations may cause or aggravate nasal obstruction.Based on history, examination, and CT scan findings, the surgery was planned accordingly.In addition to septoplasty and inferior turbinate reduction, many additional procedures were done based on CT scan findings.Intraoperative endoscopic findings like para nasal sinus mucosal thickenings, PMT, enlarged inferior turbinate, concha bullosa, and OMC pathologies were recorded.All the sinuses showing mucosal thickening or opacities on the preoperative CT scans were operated on and the findings were recorded on the basis of the presence or absence of mucosal thickenings or polyposis.However, any secretions other than mucopurulent in the osteomeatal area and sinuses were considered to be a negative endoscopic finding.

Statistical evaluation
Spreadsheets were used to compile and input the data.Version 24.0 of SPSS's data editor was exported (SPSS Inc., Chicago, IL, USA).Frequency and percentage were used to summarize categorical variables.For each parameter of relevance, the McNamara chi-square test has been utilized for comparing CT results to intraoperative findings.A p-value < 0.05 has been determined statistically significant and 2-tailed p-values have been presented.STATA version 15 was used for the statistical analysis.
In this study, a comparison of NCCT findings and intraoperative findings was done.There was a time gap of 4.5 weeks on average between CT scan and surgery.Maxillary sinus mucosal thickening had been found in 28 (14.0%)patients on CT scan but only in 8 (4.0%) patients intraoperatively (Fig. 1).Anterior ethmoid sinus mucosal thickening had been found in 20 (10.0%) patients on CT   scan but only in 6 (3.0%) patients intraoperatively (Fig. 2).

Discussion
Nasal obstruction is the frequent complaint in otolaryngology clinics and deviated nasal septum is the frequent isolated cause of nasal obstruction.Symptomatic DNS can be an isolated entity or it can be associated with other anatomical or pathological conditions causing or Most of these patients with nasal obstruction secondary to deviated nasal septum need corrective surgery in the form of septoplasty with or without turbinate reduction.Some patients need additional procedures depending upon CT scans and/or other investigations.Septoplasty with or without inferior turbinate reduction improves nasal airway and therefore quality of life in these patients [13].
CT is the current imaging standard of choice in evaluating the nose and paranasal sinus pathology and anatomy.It is currently the preferred tool to visualize anatomical borders and to detect pathology in the nose and paranasal system.The role of CT scan in the preoperative evaluation of symptomatic DNS is inconclusive in the literature.Some studies clearly demonstrate its role in symptomatic DNS [12,14,15] while others are against it [16][17][18].This study was done to evaluate CT scan findings in symptomatic DNS patients and compare those findings with intraoperative endoscopic findings.
In this study, most of the patients were young with 130 (65%) patients between 20 and 30 years of age.The mean age in years was 26.4 ± 3.2 years.The average time from CT scan to surgery was 4.2 weeks.Adeel et al. [19] in their study had a mean age of 31.0 + 13.15.Similar research by Kanwar et al. [20] found that the majority of patients (33%) in their research were between the ages of 21 and 30.All patients present with nasal obstruction.Other symptoms present were headache, snoring, sneezing, nasal discharge, and nasal bleeding.Most common type of DNS was C-shaped present in 142 (72.0%) patients followed by S-shaped DNS in 30 (15.0%) and DNS with spur in 28 (14.0%)patients.According to Kanwar et al. [20], DNS was present on the right side of 43.9% of patients and on the left of 28.5% of patients.Rehman et al. [21] discovered left-sided DNS in 40.5% of patients and right-sided DNS in 59.4% of patients.In another study by Moorthy et al. [22], 90% of patients had C-shaped DNS, whereas 10% had S-shaped DNS.
In this study, agar nasi cell was seen in 27 (13.5%)patients, onodi cells 11 (6.5%) patients, haller cells in 14 (7.0%) patients, and pneumatized uncinate in 6 (3.0%) patients.Haller cells have been observed in 13 (8.6%) of the patients in research by Wani et al. [27] and abnormal agger nasi cells in 14 (9.33%) of their patients.Chevan et al. [20] in their series of 50 patients found ITH in 60%, and paradoxical MT in 16% concha bullosa in 44% of their patients.Dar et al. [15] in their study found onodi cells in 9 (7.5%) patients, haller cells in 10 (8.3%) patients, pneumatized uncinate in 4 (3.3%)patients, and agger nasi cells in 17 (14.2%)patients; OMC was blocked in 5.8% of their patients.In a similar study by Eylgor et al. [25] agger nasi cells were present in 16.1% of patients and haller cells in 9.3% of patients.In a different research, Chakraborty et al. [24] discovered that agger nasi cells were present in 26.8% of patients, PMT was in 14.63% of patients, and onodi cells were in 10.9% of patients.
A correlation of pathological findings between CT scans and intraoperative endoscopy in symptomatic DNS patients is sparse in literature unlike patients with chronic rhinosinusitis where excellent correlation has been found by many studies.Only a few studies were found on the subject.In this study, a comparison of NCCT findings and intraoperative findings was done.The maxillary sinus was the most frequent sinus involved.Maxillary sinus mucosal thickening had been seen in 28(14%) patients on CT scan but only in 8(4%) patients intraoperatively.Anterior ethmoid sinus mucosal thickening had been found in 20(10%) patients on CT scan but only in 6(3%) patients intraoperatively.Posterior ethmoidal sinus mucosal thickening had been observed in 12(6%) patients on CT scan but only in 3(1.5%) patients intraoperatively.Sphenoid sinus mucosal thickening had been found in 11 patients on CT scan but only in 2 patients intraoperatively.Frontal sinus mucosal thickening had been found in 4 patients on CT scan but only in 1 patient intraoperatively.PMT had been observed in 20 patients on CT scan and 20 patients intraoperatively.Enlarged inferior turbinate had been observed in 103 patients on CT scan and 103 patients intraoperatively.PMT/concha bullosa turbinate had been observed in 22 patients on CT scan and 22 patients intraoperatively.In related research by Dar et al. [15], mucosal thickening of the maxillary sinus had been observed in 16 (13.3%)patients, as well as anterior and posterior ethmoid sinus disease in 8 (6.7%), sphenoid sinus disease in 2 (1.7%), and frontal sinus disease in 1 (0.8%) patients.In a research by Mohebbi et al. [34], bilateral maxillary sinusitis had been observe in 27% of patients while unilateral disease had been observe in 18.4%; likewise, unilateral frontal sinus involvement had been observe in 12.5% and bilaterally in 11.2%, unilateral sphenoidal sinus in 13% patients and bilateral sphenoidal sinusitis had been observe in 12.3%, bilateral ethmoidal sinusitis had been observed in 36.1%, and unilateral ethmoidal sinusitis had been found in 18.1% patients.
As shown in Table 3, there was an excellent association among preoperative CT scan and intraoperative endoscopic results in terms of anatomical variations, but there was a poor correlation between pathological CT findings like mucosal thickenings, OMC block, and intraoperative endoscopic findings.Therefore, any CT scan paranasal sinus mucosal thickenings that are not supported by clinical findings should not be made basis for additional procedures.

Conclusion
From this study, we concluded that a preoperative CT scan is a poor tool for predicting sinus disease in patients without clinical features of sinus disease and has a limited role in patients with symptomatic DNS.Additional procedures were done on the basis of these incidental findings on CT.But intraoperatively, we find a poor correlation with most of these incidental pathological findings like mucosal thickenings and blocked OMC.Insurance companies and government agencies should review their policies of ordering CT scans for approving septal surgeries.Further soft tissue thickenings on CT scans without symptoms of sinus disease are not an indication for sinus surgery and most of these patients have normal or near normal sinuses on endoscopic sinus surgery when surgery was done after a few weeks following the CT scan.Further sinus mucosal thickening, or CRS, is a medical disease and surgical indications must be strong before considering the patient as a candidate for surgery.

Fig. 1 Fig. 2
Fig. 1 Preoperative CT scan and intraoperative endoscopic picture of left maxillary sinus.Left showing pre-operative CT scan with maxillary sinus opacity, on right side showing intraoperative endoscopic picture of the same patient after 4 weeks.Maxillary sinus is clear and disease-free intraoperatively

Fig. 3
Fig. 3 Preoperative CT scan and intraoperative endoscopic picture of left anterior ethmoidal sinus.Left showing pre-operative CT scan with left anterior ethmoid sinus mucosal thickenings, on right side showing intraoperative endoscopic picture of the same patient after 5 weeks.Anterior ethmoids were clear intraoperatively