Sinonasal diseases constitute a significant proportion of otorhinolaryngological disorders and frequently present with symptoms such as nasal obstruction, nasal discharge, facial pain, headache, epistaxis, and anosmia. Chronic rhinosinusitis (CRS), nasal polyposis, fungal sinusitis, sinonasal tumors, and anatomical variations of the osteomeatal complex are among the common conditions requiring surgical intervention. Functional Endoscopic Sinus Surgery (FESS) has become the standard of care for managing refractory sinonasal diseases due to its minimally invasive nature and ability to restore physiological drainage pathways.[1] Preoperative radiological assessment, particularly by computed tomography (CT) of the paranasal sinuses, plays a pivotal role in surgical planning. CT imaging provides excellent delineation of bony anatomy, extent of disease, mucosal thickening, osteomeatal complex obstruction, anatomical variations such as deviated nasal septum, concha bullosa, Haller cells, agger nasi cells, and proximity to vital structures like the orbit and skull base. These findings help surgeons anticipate intraoperative challenges and reduce the risk of complications.[2] Despite advancements in imaging techniques, discrepancies often exist between radiological findings and intraoperative observations. Certain inflammatory changes, mucosal disease severity, polypoidal involvement, or anatomical variations may appear exaggerated or underestimated on imaging compared to intraoperative findings. Similarly, radiological opacification does not always correlate with the degree of disease encountered during surgery. Such discrepancies can influence surgical decision-making, operative time, and intraoperative risk.[3] Correlating radiological findings with intraoperative findings is therefore essential to validate the diagnostic accuracy of preoperative imaging, enhance surgical planning, and optimize patient outcomes. Previous studies have reported varying degrees of concordance between CT scan findings and intraoperative observations, with some reporting high sensitivity for bony anatomy and lower accuracy for soft tissue pathology. Understanding these correlations is especially relevant in tertiary care settings where advanced disease and revision surgeries are common.[4] Aim To study the correlation between preoperative radiological findings and intraoperative findings in patients undergoing sinonasal surgeries. Objectives 1. To evaluate preoperative radiological findings on CT scan of paranasal sinuses in patients undergoing sinonasal surgery. 2. To correlate the radiological findings with intraoperative observations during sinonasal surgical procedures.

Source of Data Data were collected from patients presenting with sinonasal disease who underwent surgical management in the Department of Otorhinolaryngology at a tertiary care teaching hospital. Study Design This was a hospital-based, prospective observational study. Study Location The study was conducted in the Department of Otorhinolaryngology at a tertiary care teaching hospital. Study Duration The study was conducted over a period of 18 months, including patient recruitment, surgery, data collection, and analysis. Sample Size A total of 120 patients undergoing sinonasal surgery were included in the study. Inclusion Criteria • Patients aged ≥18 years. • Patients clinically diagnosed with sinonasal disease requiring surgical intervention. • Patients who underwent preoperative CT scan of the paranasal sinuses. • Patients who provided informed written consent. Exclusion Criteria • Patients with a history of previous sinonasal surgery. • Patients with sinonasal malignancies. • Patients with facial trauma or congenital craniofacial anomalies. • Patients unwilling to participate in the study. Procedure and Methodology All enrolled patients underwent detailed clinical evaluation including history taking and otorhinolaryngological examination. Diagnostic nasal endoscopy was performed in all cases. Preoperative CT scans of the paranasal sinuses were obtained in axial and coronal planes and evaluated for anatomical variations, extent of sinus disease, mucosal thickening, osteomeatal complex obstruction, polyposis, and bony erosion. Surgical intervention was planned based on clinical and radiological findings. During surgery, intraoperative findings were documented systematically, including anatomical variations, extent of disease, mucosal pathology, and involvement of individual sinuses. The intraoperative findings were recorded using a standardized proforma. Sample Processing Radiological findings and intraoperative observations were tabulated separately and later correlated. Each anatomical and pathological parameter was coded for statistical comparison. Statistical Methods Data were entered into Microsoft Excel and analyzed using statistical software (SPSS version 25.0). Descriptive statistics were expressed as frequencies, percentages, mean, and standard deviation. The correlation between radiological and intraoperative findings was assessed using the Chi-square test or Fisher’s exact test where appropriate. A p-value of <0.05 was considered statistically significant. Data Collection Data were collected prospectively using a predesigned and pretested proforma that included demographic details, clinical findings, radiological parameters, intraoperative observations, and final diagnosis.

Table 1: Overall correlation between preoperative radiological findings and intraoperative findings (N = 120) Measure Total (N=120) Mean±SD / n(%) Test of significance Effect size (95% CI) p-value Age (years) 36.8 ± 12.4 Male sex 71 (59.2) Duration of symptoms (months) 18.6 ± 11.7 Pre-op CT Lund-Mackay score (0-24) 11.7 ± 4.3 Intraoperative disease severity score (0-20) 10.9 ± 3.9 Correlation: CT score vs intraop severity Pearson r r = 0.74 (0.65 to 0.81) <0.001 Correlation: CT score vs operative time (minutes) Pearson r r = 0.42 (0.26 to 0.56) <0.001 Operative time (minutes) 74.6 ± 21.8 Intraop blood loss (mL) 86.7 ± 41.2 Correlation: CT score vs blood loss Pearson r r = 0.31 (0.14 to 0.47) 0.001 Intraop severity grade (tertiles) Mild 32 (26.7); Moderate 49 (40.8); Severe 39 (32.5) CT score across severity grades Mild 7.4±2.1; Moderate 11.2±2.9; Severe 14.8±3.1 One-way ANOVA η² = 0.54 (0.42 to 0.63) <0.001 Severe vs Mild CT score (pairwise) Tukey post-hoc Mean diff = +7.4 (6.1 to 8.6) <0.001 Table 1 presents the overall demographic characteristics, radiological scores, intraoperative findings, and their correlations among 120 patients undergoing sinonasal surgery. The mean age of the study population was 36.8 ± 12.4 years, with a male predominance (59.2%). The mean duration of symptoms prior to surgery was 18.6 ± 11.7 months. Preoperative radiological assessment using the Lund-Mackay scoring system revealed a mean score of 11.7 ± 4.3, while the mean intraoperative disease severity score was 10.9 ± 3.9, indicating moderate disease burden in the study population. A strong positive correlation was observed between preoperative CT Lund-Mackay scores and intraoperative disease severity (r = 0.74; 95% CI: 0.65-0.81; p < 0.001), suggesting that radiological severity reliably predicted operative findings. Additionally, CT scores demonstrated a moderate positive correlation with operative time (r = 0.42; 95% CI: 0.26-0.56; p < 0.001), indicating increased surgical complexity with higher radiological involvement. A weaker but statistically significant correlation was also observed between CT scores and intraoperative blood loss (r = 0.31; 95% CI: 0.14-0.47; p = 0.001). When disease severity was stratified intraoperatively, 26.7% had mild disease, 40.8% had moderate disease, and 32.5% had severe disease. Corresponding CT scores increased significantly across severity grades, with mean values of 7.4 ± 2.1 for mild, 11.2 ± 2.9 for moderate, and 14.8 ± 3.1 for severe disease. One-way ANOVA demonstrated a highly significant difference between groups (η² = 0.54; p < 0.001), and post-hoc analysis confirmed a significant difference between mild and severe disease categories (mean difference = 7.4; 95% CI: 6.1-8.6; p < 0.001). Table 2: Preoperative CT scan findings of paranasal sinuses by clinical phenotype (N = 120) CT finding Total (N=120) n(%) CRSsNP (n=68) n(%) CRSwNP (n=52) n(%) Test of significance Effect size (95% CI) p-value Osteomeatal complex (OMC) obstruction 63 (52.5) 22 (32.4) 41 (78.8) χ² = 25.4 RR = 2.43 (1.66 to 3.57) <0.001 Maxillary mucosal thickening >4 mm 83 (69.2) 39 (57.4) 44 (84.6) χ² = 10.1 RR = 1.47 (1.16 to 1.87) 0.001 Ethmoid opacification (partial/complete) 87 (72.5) 40 (58.8) 47 (90.4) χ² = 14.0 RR = 1.54 (1.21 to 1.95) <0.001 Frontal sinus opacification 44 (36.7) 18 (26.5) 26 (50.0) χ² = 7.1 RR = 1.89 (1.16 to 3.07) 0.008 Sphenoid sinus opacification 29 (24.2) 13 (19.1) 16 (30.8) χ² = 2.2 RR = 1.61 (0.87 to 2.98) 0.13 Deviated nasal septum (DNS) 58 (48.3) 37 (54.4) 21 (40.4) χ² = 2.3 RR = 0.74 (0.50 to 1.10) 0.13 Concha bullosa 33 (27.5) 19 (27.9) 14 (26.9) χ² = 0.02 RR = 0.97 (0.54 to 1.75) 0.89 Haller cell 17 (14.2) 8 (11.8) 9 (17.3) Fisher exact RR = 1.47 (0.61 to 3.53) 0.42 Agger nasi cell prominence 28 (23.3) 12 (17.6) 16 (30.8) χ² = 2.9 RR = 1.75 (0.94 to 3.26) 0.09 Osteitis / bony sclerosis 22 (18.3) 9 (13.2) 13 (25.0) χ² = 2.7 RR = 1.89 (0.88 to 4.04) 0.10 Table 2 depicts the distribution of preoperative CT findings among patients with chronic rhinosinusitis without nasal polyps (CRSsNP; n=68) and with nasal polyps (CRSwNP; n=52). Osteomeatal complex obstruction was significantly more frequent in CRSwNP patients (78.8%) compared to CRSsNP patients (32.4%), with a relative risk (RR) of 2.43 (95% CI: 1.66-3.57; p < 0.001). Similarly, maxillary sinus mucosal thickening greater than 4 mm was significantly higher in the CRSwNP group (84.6% vs 57.4%; RR = 1.47; p = 0.001). Ethmoid sinus opacification was observed in 72.5% of the total cohort and was significantly more common in CRSwNP patients (90.4%) than CRSsNP patients (58.8%), showing a strong association (RR = 1.54; p < 0.001). Frontal sinus opacification also showed a significant association with polypoidal disease (50.0% vs 26.5%; RR = 1.89; p = 0.008). In contrast, sphenoid sinus involvement, deviated nasal septum, concha bullosa, Haller cells, and agger nasi cell prominence did not demonstrate statistically significant differences between the two groups (p > 0.05), although these anatomical variations were commonly encountered. Osteitis or bony sclerosis showed a higher frequency in CRSwNP patients (25.0% vs 13.2%), but this difference did not reach statistical significance (p = 0.10). Table 3: Correlation of CT findings with intraoperative observations (agreement analysis) (N = 120) Parameter CT positive n(%) Intraop positive n(%) Test of significance Effect size (95% CI) p-value OMC obstruction 63 (52.5) 67 (55.8) McNemar Agreement = 88.3%; κ = 0.77 (0.66 to 0.88) 0.42 Diagnostic validity Sensitivity 86.6% (76.1-93.1); Specificity 90.6% (79.7-96.1) Maxillary sinus disease 79 (65.8) 82 (68.3) McNemar Agreement = 89.2%; κ = 0.74 (0.62 to 0.86) 0.58 Diagnostic validity Sensitivity 90.2% (81.5-95.3); Specificity 86.8% (71.9-94.6) Ethmoid disease 85 (70.8) 88 (73.3) McNemar Agreement = 90.8%; κ = 0.75 (0.62 to 0.87) 0.55 Diagnostic validity Sensitivity 92.0% (84.4-96.1); Specificity 87.5% (71.0-95.5) Frontal sinus disease 42 (35.0) 38 (31.7) McNemar Agreement = 91.7%; κ = 0.80 (0.69 to 0.91) 0.18 Diagnostic validity Sensitivity 92.1% (79.2-97.3); Specificity 91.5% (83.4-95.8) Sphenoid sinus disease 29 (24.2) 27 (22.5) McNemar Agreement = 91.7%; κ = 0.72 (0.56 to 0.87) 0.56 Diagnostic validity Sensitivity 85.2% (67.5-94.1); Specificity 93.5% (86.5-97.1) Concha bullosa 34 (28.3) 31 (25.8) McNemar Agreement = 90.8%; κ = 0.78 (0.66 to 0.90) 0.51 Diagnostic validity Sensitivity 90.3% (74.2-96.8); Specificity 91.0% (83.1-95.5) Deviated nasal septum (DNS) 58 (48.3) 61 (50.8) McNemar Agreement = 87.5%; κ = 0.75 (0.63 to 0.86) 0.31 Diagnostic validity Sensitivity 85.2% (73.7-92.0); Specificity 87.3% (75.7-93.9) Table 3 illustrates the agreement between radiological findings and intraoperative observations for various sinonasal parameters. High levels of agreement were observed across most anatomical regions. Osteomeatal complex obstruction demonstrated an agreement rate of 88.3%, with substantial agreement (κ = 0.77; 95% CI: 0.66-0.88). CT showed good diagnostic accuracy for OMC obstruction with sensitivity of 86.6% and specificity of 90.6%. Similarly, maxillary sinus disease showed an agreement of 89.2% (κ = 0.74), with high sensitivity (90.2%) and specificity (86.8%). Ethmoid sinus disease demonstrated excellent concordance, with 90.8% agreement and κ = 0.75, supported by sensitivity of 92.0% and specificity of 87.5%. Frontal sinus disease exhibited one of the highest agreement levels at 91.7% (κ = 0.80), with excellent diagnostic performance. Sphenoid sinus disease also showed high agreement (91.7%; κ = 0.72) and high specificity (93.5%). Concha bullosa and deviated nasal septum similarly demonstrated strong agreement between CT and intraoperative findings, with kappa values exceeding 0.75 and diagnostic accuracy exceeding 85%. Figure 1: ROC curve with AUC

The present study demonstrated a strong correlation between preoperative CT findings and intraoperative disease severity in patients undergoing sinonasal surgery. The mean age of 36.8 ± 12.4 years and male predominance (59.2%) observed in this cohort are comparable to findings reported by Manik S et al. (2021) [5], where sinonasal inflammatory diseases were most prevalent in the third to fifth decades with male preponderance. The mean preoperative Lund-Mackay score of 11.7 ± 4.3 and intraoperative severity score of 10.9 ± 3.9 indicate moderate disease burden in most patients. A strong positive correlation was observed between CT score and intraoperative severity (r = 0.74, p < 0.001), emphasizing the reliability of CT imaging in predicting the extent of surgical disease. Similar strong correlations have been reported by Paglia F et al. (2022) [6], who demonstrated that higher CT scores were consistently associated with increased mucosal disease and surgical complexity. Ritter A et al. (2020) [7] Furthermore, the present study found a moderate positive correlation between CT scores and operative time (r = 0.42, p < 0.001), suggesting that extensive radiological disease prolongs surgical duration. This finding is consistent with studies by Wormald et al. [5], who observed increased operative difficulty and time in patients with higher Lund-Mackay scores. A weaker but statistically significant correlation between CT score and intraoperative blood loss (r = 0.31, p = 0.001) was also noted, supporting earlier reports by Baban MI et al. (2020) [8], who highlighted increased bleeding in extensive inflammatory disease. Stratification of patients into mild, moderate, and severe intraoperative disease revealed a progressive increase in CT scores across severity grades, with a highly significant difference (p < 0.001). The large effect size (η² = 0.54) indicates a strong relationship between radiological burden and operative findings, reinforcing the clinical value of CT-based staging systems. Table 2 highlights significant differences in radiological patterns between CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Osteomeatal complex obstruction was significantly more prevalent in CRSwNP (78.8%) compared to CRSsNP (32.4%), with a relative risk of 2.43. This aligns with observations by Ritter A et al. (2020) [7], who emphasized the central role of OMC obstruction in polypoid disease. Maxillary and ethmoid sinus involvement were significantly more frequent in CRSwNP, consistent with findings by Syed MU et al. (2024)[9], who reported diffuse mucosal involvement and bilateral disease as characteristic of polypoid CRS. Frontal sinus opacification was also significantly higher in the CRSwNP group, reflecting disease extension into dependent sinus regions. In contrast, anatomical variants such as deviated nasal septum, concha bullosa, Haller cells, and agger nasi cells did not show statistically significant differences between groups. These findings suggest that while anatomical variations may contribute to sinus obstruction, inflammatory mucosal disease plays a more dominant role in polypoid CRS, supporting conclusions drawn by Shah J et al. (2021) [10]. The agreement analysis demonstrated excellent concordance between CT findings and intraoperative observations across all sinus regions. Osteomeatal complex obstruction showed substantial agreement (κ = 0.77), with high sensitivity (86.6%) and specificity (90.6%). Similar high agreement was noted for maxillary, ethmoid, frontal, and sphenoid sinus disease, with kappa values ranging from 0.72 to 0.80. These findings are consistent with those reported by Schmale IL et al. (2021) [1], who established CT imaging as the gold standard for preoperative mapping in endoscopic sinus surgery. The high diagnostic accuracy observed for ethmoid and frontal sinus disease corroborates findings by Verma P et al. (2022) [11], who emphasized CT’s superior ability to delineate complex ethmoidal anatomy and disease extent.

This study demonstrates a strong and statistically significant correlation between preoperative radiological findings and intraoperative observations in patients undergoing sinonasal surgery. The preoperative CT Lund-Mackay score showed a strong positive correlation with intraoperative disease severity, operative time, and intraoperative blood loss, highlighting the reliability of CT imaging in predicting surgical complexity. Radiological assessment accurately reflected the extent of mucosal disease, particularly in the ethmoid, maxillary, frontal, and sphenoid sinuses, with high levels of agreement observed between imaging findings and intraoperative observations. Patients with higher CT scores exhibited more extensive disease intraoperatively, reinforcing the role of CT as a crucial tool for surgical planning and risk stratification. Additionally, significant differences in radiological patterns between CRS with nasal polyps and CRS without nasal polyps were observed, emphasizing the distinct disease behavior and anatomical involvement in these subtypes. The strong agreement between CT findings and intraoperative anatomy supports the indispensability of preoperative CT scanning in enhancing surgical safety, anticipating intraoperative challenges, and improving surgical outcomes. LIMITATIONS OF THE STUDY 1. The study was conducted at a single tertiary care center, which may limit the generalizability of the findings to other populations or healthcare settings. 2. The sample size, although adequate, may not capture the full spectrum of sinonasal disease severity, particularly rare or complex pathologies. 3. Inter-observer variability in interpretation of CT scans and intraoperative findings was not formally assessed, which could influence reproducibility. 4. The study relied on conventional CT imaging without incorporating advanced imaging modalities such as cone-beam CT or MRI for soft tissue differentiation. 5. Postoperative outcomes and long-term symptom resolution were not evaluated, limiting correlation between radiological findings and long-term clinical outcomes. 6. Being an observational study, causal relationships between radiological severity and surgical outcomes could not be firmly established.

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