BRIEF RESUME OF THE INTENDED WORK:
6.1 Need for the study :-
It is well known that anatomy of paranasal sinuses have lot of Variations which predispose to certain pathologic conditions. These variants can cause narrowing or total obstruction and may impair free airflow and predispose to repeated attacks of sinusitis. During procedures like FUNCTIONAL ENDOSCOPIC SINUS SURGERY (FESS) (which have dramatically reduced patient morbidity), these variations can lead to intraorbital or intracranial complications. So, for the surgical procedures to be successful, thorough knowledge of anatomy and its variations is must, which helps in avoiding and diagnosing potential complications. Thus CT PNS is a roadway map for preoperative assessment and surgical planning. The radiologist must pay close attention to anatomical variations in preoperative evaluation.
The purpose of this study is to know in detail the normal variations of paranasal sinuses and their prevalence.
6.2 Review of literature
Many authors have given detailed descriptions of the anatomy and pathologies of the PNS using various imaging modalities. The current review of literature gives collection of their works in a nut shell.
With the advent of multidetector computed tomography (MDCT), imaging of paranasal sinuses prior to functional endoscopic sinus surgery (FESS) has become mandatory. Multiplanar imaging, particularly coronal reformations, offers precise information regarding the anatomy of the sinuses and its variations, which is an essential requisite before surgery.1
W. E. Bolger et al, in their study of coronal CT Scan of 202 patients, directed special attention towards bony anatomic variations and mucosal abnormalities.2
The coronal CT (computed tomography) of the PNS has gained importance both as a diagnostic tool and as an important part of preoperative planning, after the advent of relatively less invasive techniques of functional endoscopic sinus surgery.3
Several authors have stressed the importance of anatomic variations as a predisposing cause for sinus disease, especially of osteomeatal complex .4
The prevalence of anatomic variations has been variously described, ranging from pure anatomic descriptions to descriptions based on CT examinations.5
In a study conducted on 292 patients with the age group of 15-50years for evaluating the anatomic variations and their prevalence, they did not have any pathology in their sinuses. According to the results, the septal deviation (34.24%) was the most common and normal variation and the other cases were sequentially as follow : 1) Agger Nasi cell (36.22%), 2) Concha bullosa (15.90%), 3) Hypo plastic from sinus (6.24), 4) Aerated Septum (2.62%), 5) Haller cell (1.41%), 6) Onodi cell (0.40%).6
Headache due to the pressure of nasal mucosa in the absence of inflammation of the nose and paranasal sinuses is a clinical entity that has gained wide acceptance. Concha bullosa is the most commonly observed anatomical variation of the lateral nasal wall.7
Paradoxical curvature of the middle turbinate was found in 26.1% of patients. Haller’s cells in 45.1%pneumatization of uncinate process in 2.5% and lamellar cell of the middle turbinate was seen in 46.2% of the cases. In 31.2% pneumatization was noted in the bulbous part of turbinate and ‘true’ concha bullosa in 15.7% of the patients. The agger nasi cell was present in 98.5% of patients, crista galli pneumatization in 83.7%, bulla galli in5.4% and DNS (Deviated nasal septum) 18.8%.8
The thorough knowledge of nasal sinus anatomy and of the large number of anatomical variants in the region is necessary for performing relatively less invasive surgical techniques particularly FESS ie Functional endoscopic sinus surgery. Many of these variations are detectable only by the use of CT.9
. Valerie J. Lund et al (2000) concluded that computerized tomography (CT) offers the gold standard in terms of imaging the extent of the disease and fine detailed anatomy. Neither plain X-rays nor Magnetic Resonance Imaging (MRI) offer optimal information in this respect. CT scanning has allowed the radiologist to image PNS disease with accuracy and detail never before attainable.10
6.3 Aims And Objectives Of The Study
1. To document the anatomical variations of paranasal sinuses using coronal
CT scans and
2. To assess the frequency of occurrence of these variations.
7.1 Materials And Methods
Source of data; Subjects with complaints pertaining to PNS,
who are referred from ENT OPD and ward
from 1/1/2014 to 31/12/2014.
Study duration; 18 Months.
Study design; Explorative study.
Study area Mysore medical college & research institute. MYSORE
Sample size; 100.
Statistical methods; 1. Descriptive
4. Chi-square test.
SPSS for windows (version 16.0) will be employed for statistical analysis.
METHOD OF COLLECTION OF DATA:
Details of the study protocol will be explained to the subjects.
The patients will be subjected to Coronal CT scans of PNS taking 5mm slices with 3mm retro reconstruction using GE SYSTEMS- HI SPEED DUAL SLICE CT. The images will be reviewed in both bone and soft tissue algorithms for the following variations :
1. Septum Deviation.
2. Agger nasi pneumatized.
3. Bulla Ethmoidalis.
4. Uncinate process.
5. Middle turbinate: Pneumatisation.
6. Maxillary sinus septation.
7. Pneumatized superior turbinate:
8. Supraorbital cell:
9. Haller cell:
10. Onodi cell:
11. Frontal sinus:
12. Cribriform Plate:
13. Extramural sphenoid pneumatization:
14. Other findings: inflammatory sinus disease acute, chronic or allergic.
If present in which sinus?
1.Patients included in the study will be those with complaints pertaining to PNS,
and referred from the ENT OPD and wards.
Previous sinonasal surgery (excluding nasoantral window antrostomy).
Sinonasal anatomy alteration or obscuration due to inflammatory diseases (When bony detail was obscured by polypoid mucosal disease).
Paranasal sinus neoplasm.
Does the study require any investigation/intervention to be
Conducted on patients/humans/animals? If so please describe briefly.
*CT paranasal sinuses required as part of routine clinical evaluation of paranasal
7.4 Has ethical clearance been obtained from your institution?
Reddy UM, Dev B. Pictorial essay: Anatomical variations
of paranasal sinuses on multidetector computed tomography-How does it help FESS surgeons?. Indian J Radiol Imaging 2012;22:317-24.
2. Bolger, W. E., Parsons, D. S. and Butzin, C. A. (1991), Paranasal sinus bony anatomic variations and mucosal abnormalities: CT analysis for endoscopic sinus surgery. The Laryngoscope, 101: 56–64. doi: 10.1288/00005537-199101000-00010
3. Zeinreich S J, Kennedy D W, Rosenbaum AE. Paranasal sinuses: CT imaging requirements for endoscopic surgery. Radiology 1987; 163:769-775.
4.Babbel R, Harnsberger HR, Welson B, et al. Optimization of techniques in screening CT of the sinuses. AJR (American journal of radiology) 1991; 157:1093-1098.
5. Mafee MF, Endoscopic sinus surgery: role of the radiologist. Ame. J Neuroradiology 1991; 12; 885-860
6.Mohammad Hosein Daghighi. Amir Daryani. Evalautionof anatomic variations of paranasal sinuses. The Internet Journal of OtorhinolaryngologyTM ISSN:1528-8420.
7. A Peric, N Baletic, and J Sotirovic. A case of an uncommon anatomic variation of the middle turbinate associated with headache. Acta Otorhinolaryngol Ital. 2010 June ; 30 (3) : 156-159.
8.. Bilaniuk LT and Zimmerman RA.Computed tomography in evaluation of the paranasal sinuses. Radiology clinics Nor Am March 1982; 20(1):51-66.
9. G Marmolya, EJ Wiesen, R Yagan, CD Haria and AC Shah. Paranasal sinuses: Low-Dose CT, Radiology December 1991:181; 689-691.
10. John R, Hasselink, Alfred L Weber, Paul F.Evaluation of Mucoceles of the paranasal sinuses with computed tomography, Radiology, november1979:133; 397-400..