Diagnostic Nasal Endoscopy (DNE)

Diagnostic Nasal Endoscopy (DNE) is a minimally invasive, office-based procedure that allows direct visualisation of the nasal cavity and nasopharynx using a rigid endoscope. It gives a magnified, illuminated, real-time image of the nasal passages and sinus openings. It uses rigid telescopes of varying angles (0°, 30°, 45°, 70°) to visualise structures that cannot be seen by anterior or posterior rhinoscopy. This procedure has replaced older mirror-based examinations because it provides better diagnostic accuracy and helps in planning and postoperative assessment of Functional Endoscopic Sinus Surgery (FESS).

Therefore, every MBBS and ENT postgraduate student must understand the indications, equipment, and techniques in detail. DNE is not only a diagnostic tool but also a gateway to functional endoscopic sinus surgery (FESS) and other therapeutic procedures.

Indications for Diagnostic Nasal Endoscopy

1. Initial Diagnosis of Sinonasal Disease: In patients presenting with symptoms like nasal obstruction, mucopurulent discharge, facial pain/pressure, or decreased sense of smell (hyposmia/anosmia).
2. Monitoring Treatment Response: Furthermore, to both medical and surgical treatments. This includes noting the resolution of mucosal oedema, polyps, or purulent secretions following a course of antibiotics or topical steroids.
3. Complications of Sinusitis: It evaluates patients with suspected complications or impending complications of rhinosinusitis, such as a subperiosteal abscess or intracranial extension.
4. Epistaxis (Nosebleed) Evaluation: Identification of the site of bleeding (e.g., vessel in Kiesselbach’s plexus or a posterior bleeding point), thus guiding targeted treatment.
5. Biopsy and Mass Evaluation: It allows for the focused evaluation and precise biopsy of nasal or nasopharyngeal masses/tumours, leading to an accurate tissue diagnosis.
6. Cerebrospinal Fluid (CSF) Leak Diagnosis: Identifying the specific location of a Dural tear in cases of CSF rhinorrhoea.
7. Evaluation of Nasopharynx: It provides a detailed assessment of the nasopharynx for adenoid hyperplasia (especially in adults), Eustachian tube dysfunction, or nasopharyngeal carcinoma (NPC).
8. Foreign Body Retrieval: Clearly, Removal of nasal foreign bodies, particularly in children.
9. Obtaining Purulent Secretions: DNE allows the clinician to obtain an uncontaminated sample of purulent secretions directly from the middle meatus for culture and sensitivity testing.

Equipment and Preparation for Diagnostic Nasal Endoscopy

1. Endoscopes: Rigid telescopes of 0°, 30°, 45°, and 70° with diameters of 2.7 mm (for children) or 4 mm (for adults).
   • The 0° endoscope views structures directly in front.
   • The 30° and 45° scopes help visualise lateral or posterior recesses.
   • The 70° endoscope is used for difficult angles like the roof of the nasal cavity or sphenoid ostium. (Colour codes used: Green – 0°, Red – 30°, Black – 45°, Yellow – 70°.)
2. Camera and Monitor: A high-definition video camera connected to the endoscope transmits the image to a monitor, allowing magnified visualisation and documentation.
3. Light Source: A cold light source—usually xenon or LED—provides bright, white illumination through a fibre-optic cable.
4. Ancillary Instruments: Suction tips, Freer elevators, and small forceps help retract mucosa or clear secretions during the examination.
5. Antifog Solution: Savlon™ or commercial antifog spray keeps the lens clear.
6. Topical Agents: Cotton pledgets soaked in 4 % lignocaine with a vasoconstrictor (like adrenaline or oxymetazoline) provide local anaesthesia and decongestion.

Anaesthesia and Position of Diagnostic Nasal Endoscopy

1. Anaesthesia: Topical anaesthesia is standard. Therefore, the nose is packed with cotton patties for 4-5 minutes, soaked in a solution containing a local anaesthetic (e.g., 4%  Lignocaine/Xylocaine) and a vasoconstrictor (e.g., Adrenaline 1:1000 or Oxymetazoline).
2. Purpose: The packing achieves two goals: local anaesthesia for patient comfort and nasal decongestion to shrink the mucosa, which creates better working space.

DNE Technique: The Three-Pass Examination

The procedure is systematically performed in three passes, ensuring all critical anatomical areas are examined. Read  🔗Anatomy of Internal Nose:

1. The First Pass (Inferior Meatus and Nasopharynx). Pass the 0° endoscope along the floor of the nose, between the inferior turbinate and the nasal septum. The posterior part of the nasal cavity is inspected first, and then the scope is withdrawn to examine the front.

• Structures Examined:
  • Nasal Septum: Note any deviation, spurs, or crusting.
  • Inferior Turbinate: Assess for hypertrophy or mucosal disease, especially the posterior end of the inferior turbinate. 
  • Posterior Choanae: Visualise the junction between the nose and nasopharynx.
  • Nasopharynx: Identify the Eustachian tube orifice, adenoids (especially in children), and the Fossa of Rosenmüller (a common site for Nasopharyngeal Carcinoma).
  • Inferior Meatus: Examine the opening of the nasolacrimal duct (Hasner’s valve). 
• Importance (VIVA/Practical): Assesses the nasopharynx and the inferior turbinate. Always look for masses in the Fossa of Rosenmüller.

 

 

2. The Second Pass (Sphenoethmoidal Recess and Superior Turbinate). Pass the 0° endoscope along the floor of the nose till the posterior choanae and angle upward towards the roof of the nose. 

• Structures Examined:
  • Superior Turbinate and Meatus: Visualise this area and check for polyps emerging from it, which may suggest disease in the posterior ethmoid cells.
  • Sphenoethmoidal Recess: The area just above the superior turbinate and medial to the septum. It is bounded superiorly by the base of the skull.
  • Sphenoid Ostium: The opening of the sphenoid sinus, which drains into the sphenoethmoidal recess. It lies about 1 to 1.5 cm above the roof of the posterior choana.
  • Olfactory Cleft: The area containing the olfactory mucosa (responsible for smell); examine for pathology like polyps or inflammation that could cause anosmia.
  • Woodruff’s Plexus. It is present below the sphenoid ostium, near the roof of the posterior choana.
• Importance (VIVA/Practical): Visualises the sphenoid ostium, which is crucial for posterior pathology and is a high-yield area for posterior ethmoid and sphenoid sinus disease.

3. The Third Pass (Middle Meatus and Ostiomeatal Complex). The endoscope is gently rolled beneath the middle turbinate to inspect the middle meatus (ostiomeatal complex). The scope can sometimes be passed from behind the middle turbinate, where the space is wider.

• Structures Examined:
  • Osteomeatal Complex (OMC): The key area! Look for pus, oedema, or polyps blocking this critical drainage pathway.
  • Middle Turbinate: Assess its position, size, and health (e.g., concha bullosa, medialisation).
  • Ethmoidal Bulla (Bulla Ethmoidalis), Uncinate Process, Hiatus Semilunaris: These are the bony landmarks of the OMC.
  • Frontal Recess: The drainage pathway for the frontal sinus.
  • Maxillary Sinus Ostium: If you see an opening for the Maxillary Sinus, it is almost always the accessory ostium (a secondary opening). The natural opening of the maxillary sinus is usually found deep within the hiatus semilunaris.
• Importance (VIVA/Practical): It is an important pass. The OMC (main drainage area for the Maxillary and Frontal sinuses) is the “key area” in the pathogenesis of Chronic Rhinosinusitis (CRS). Always document the state of the middle meatus. 

Practical Tip: When documenting your DNE findings for a case presentation, always systematically describe the condition of the Septum, Inferior Turbinate, Middle Meatus (OMC), and Nasopharynx. This is the structure expected by the examiner. A 45°  endoscope is better for looking at the Sphenoid Ostium or the Hasner Valve.

Complications of Diagnostic Nasal Endoscopy

DNE is safe, but minor issues can occur:

• Mild bleeding: The commonest, controlled by vasoconstrictor drops.
• Pain or discomfort: If anaesthesia is inadequate.
• Sneezing or lacrimation: Reflex stimulation of the nasal mucosa.
• Vasovagal syncope: Rare; prevented by reassurance and gentle handling.
• Infection: Extremely uncommon with sterile technique.

———End of Chapter———-

High-Yield Points for Quick Revision

• Key Pathogenesis Area: The Osteomeatal Complex (OMC) is the narrowest and most critical area in the nose; its blockage is the primary event in the pathogenesis of Chronic Rhinosinusitis (CRS).
• Endoscope Angulation: Use the 0° scope for the first pass (general survey/floor) and the 30° scope for the second and third passes (OMC/corners).
• OMC Components: The OMC consists of the Uncinate Process, Ethmoidal Bulla, and Hiatus Semilunaris.
• Sphenoid Sinus Drainage: The sphenoid sinus drains into the Sphenoethmoidal Recess.
• Fossa of Rosenmüller: The most common site for Nasopharyngeal Carcinoma (NPC).
• Common Complication: The most frequent (though minor) complication is epistaxis (bleeding) due to mucosal trauma or suctioning.

Clinical Case Scenarios (Practical/VIVA Preparation)

These scenarios prepare you for the problem-solving and presentation skills required in the clinical setting.

1. Case 1 (Chronic Rhinosinusitis): A 45-year-old male presents with a 3-month history of thick, greenish post-nasal drip, facial pressure, and hyposmia. Anterior rhinoscopy is normal. You perform a DNE. What is the most likely finding, and which pass is critical for diagnosis?
   • Answer: The most likely finding is mucopurulent discharge and mucosal oedema blocking the middle meatus (i.e., OMC obstruction). The Second Pass (OMC Pass) is critical as it confirms the source of the pus (maxillary, frontal, or anterior ethmoid sinuses). The diagnosis is Chronic Rhinosinusitis without Nasal Polyps (CRSsNP).
2. Case 2 (Paediatric Emergency): A 5-year-old child presents to the emergency room with unilateral, foul-smelling, greenish nasal discharge that his mother noticed 3 days ago. What is your immediate diagnostic step, and what equipment do you prioritise?
   • Answer: The immediate suspected diagnosis is Nasal Foreign Body. The diagnostic step is a DNE (or sometimes just a good anterior rhinoscopy). You must prioritise the 2.7 mm endoscope to minimise trauma and facilitate visualisation/retrieval.
3. Case 3 (Nasopharyngeal Mass): A 16-year-old male presents with recurrent epistaxis (nosebleeds) and progressive nasal obstruction, predominantly on the right side. On DNE, you see a vascular, reddish-purple mass filling the posterior choana. What is your provisional diagnosis and the next crucial step?
   • Answer: The classic presentation is for Juvenile Nasopharyngeal Angiofibroma (JNA), especially in an adolescent male with unilateral posterior mass and epistaxis. Crucial Step: NEVER biopsy this mass in the clinic due to the risk of catastrophic bleeding. The next step is a CT Angiogram/MRI to confirm the diagnosis and assess the extent of the tumour and its feeding vessels.

NEET PG Style Multiple Choice Questions (MCQs)

1. The most critical anatomical area to visualize during Diagnostic Nasal Endoscopy, as it is key to the pathogenesis of Chronic Rhinosinusitis, is the: A. Inferior Meatus B. Sphenoethmoidal Recess C. Fossa of Rosenmüller D. Osteomeatal Complex (OMC)
2. Which endoscope angulation is most suitable for examining the Osteomeatal Complex (OMC) from a lateral approach? A. 0° B. 30° C. 70° D. 90°
3. The structure that drains into the Sphenoethmoidal Recess is the: A. Frontal Sinus B. Maxillary Sinus C. Sphenoid Sinus D. Anterior Ethmoid Cells
4. Before performing Diagnostic Nasal Endoscopy, the packing solution typically contains a vasoconstrictor like Adrenaline primarily to achieve: A. Pain relief B. Mucosal decongestion C. Anti-inflammatory effect D. Anti-bacterial effect
5. The most common site for Nasopharyngeal Carcinoma (NPC) detected during the first pass of DNE is the: A. Inferior Turbinate B. Sphenoid Ostium C. Fossa of Rosenmüller D. Eustachian Tube Orifice
6. Which of the following is NOT a component of the Osteomeatal Complex (OMC)? A. Uncinate Process B. Bulla Ethmoidalis C. Hiatus Semilunaris D. Inferior Turbinate
7. The main purpose of using a 2.7 mm endoscope over a 4.0 mm endoscope in paediatric patients is: A. Better light intensity B. Better magnification C. Reduced risk of nasal trauma D. Better visualization of the posterior choanae
8. In a case of suspected Juvenile Nasopharyngeal Angiofibroma (JNA), the finding on DNE is typically a mass located in the: A. Middle Meatus B. Frontal Recess C. Posterior Choanae D. Inferior Meatus
9. Which of the following is considered the Third Pass structure? A. Inferior Meatus B. Maxillary Sinus Ostium C. Sphenoid Ostium D. Nasolacrimal Duct Opening
10. A complication of DNE that is usually mild and easily controlled with nasal drops is: A. CSF Leak B. Intracranial haemorrhage C. Epistaxis (bleeding) D. Orbital haematoma

Answers and Explanations

1. D. Osteomeatal Complex (OMC): The OMC’s anatomical obstruction is the primary driver of CRS, making its evaluation the most critical step.
2. B. 30°: The 30° scope allows the examiner to look laterally (around the corner of the middle turbinate) into the middle meatus where the OMC is located.
3. C. Sphenoid Sinus: The sphenoid sinus is the most posterior sinus, and it drains via the sphenoid ostium into the sphenoethmoidal recess.
4. B. Mucosal decongestion: The vasoconstrictor (Adrenaline) shrinks the nasal mucosa, providing a wider, safer working space and better visualization.
5. C. Fossa of Rosenmüller: This is the lateral recess of the nasopharynx and the classic location for NPC.
6. D. Inferior Turbinate: The Inferior Turbinate is a separate structure below the OMC, draining the nasolacrimal duct into the inferior meatus.
7. C. Reduced risk of nasal trauma: The smaller diameter is crucial for the narrow nasal passages of children.
8. C. Posterior Choanae: JNA originates in the posterolateral wall of the nasopharynx, often presenting as a mass filling the posterior choanae.
9. C. Sphenoid Ostium: The sphenoid ostium is visualized via the Sphenoethmoidal Recess during the third pass.
10. C. Epistaxis (bleeding): This is the most common, generally minor complication, often resulting from suction or instrument manipulation.

Frequently Asked Questions in Viva

• What is the difference between anterior rhinoscopy and DNE? DNE provides a magnified, brilliantly illuminated visualisation of the entire nasal cavity and nasopharynx (including the OMC and posterior structures), which anterior rhinoscopy (using a speculum) cannot do.
• Which endoscope is used for the OMC examination?, The 30° angled endoscope is essential for the second pass to visualise the Osteomeatal Complex (OMC), allowing the clinician to look around the middle turbinate into the middle meatus.
• What is the significance of the Fossa of Rosenmüller in DNE?, The Fossa of Rosenmüller, located in the nasopharynx, is the most common site of origin for Nasopharyngeal Carcinoma (NPC), thus requiring meticulous examination during the first pass.
• Can DNE be performed with a perforated eardrum?, Yes, DNE is performed within the nose and is unrelated to the middle ear/tympanic membrane; therefore, a perforated eardrum does not contraindicate the procedure.
• What steps are taken to prevent lens fogging during DNE?, The endoscope tip is typically dipped in an anti-fog solution (e.g., Savlon™) and then briefly warmed in the clinician’s hand or in warm water before insertion to equalise temperature and prevent moisture condensation.
• Is Diagnostic Nasal Endoscopy performed under general anaesthesia?, No, DNE is typically performed as an outpatient procedure under topical anaesthesia using Lignocaine and a vasoconstrictor like Adrenaline.

———–End———–

Reference Textbooks.

• Scott-Brown, Textbook of Otorhinolaryngology-Head and Neck Surgery.
• Cummings, Otolaryngology-Head and Neck Surgery.
• Stell and Maran’s, Textbook of Head and Neck Surgery and Oncology.
• Ballenger’s, Otorhinolaryngology Head And Neck Surgery
• Susan Standring, Gray’s Anatomy.
• Frank H. Netter, Atlas of Human Anatomy.
• B.D. Chaurasiya, Human Anatomy.
• P L Dhingra, Textbook of Diseases of Ear, Nose and Throat.
• Hazarika P, Textbook of Ear Nose Throat And Head Neck Surgery Clinical Practical.
• Mohan Bansal, Textbook of Diseases of Ear, Nose and Throat Head and Neck Surgery.
• Hans Behrbohm, Textbook of Ear, Nose, and Throat Diseases With Head and Neck Surgery.
• Logan Turner, Textbook of Diseases of The Nose, Throat and Ear Head And Neck Surgery.
• Arnold, U. Ganzer, Textbook of  Otorhinolaryngology, Head and Neck Surgery.
• Ganong’s Review of Medical Physiology.
• Guyton & Hall Textbook of Medical Physiology.

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