1. Definition (Ultra-Clear ENT Format)

• Meningiocoele is a neural tube closure defect in which meninges herniate through a bony defect in the skull base.

• The herniating sac contains CSF + meninges only (NO brain parenchyma).

• When brain tissue is also present, the lesion is termed meningoencephalocele (important MCQ).

• ENT relevance: protrusion may occur into the nasal cavity, mimicking a nasal mass in infants.

---

2. Embryology of Skull Base & Pathogenesis (ENT-Exam Level Deep)

Congenital meningiocoele arises due to failure of neural tube closure around 3rd–4th week of gestation.

2.1 Embryological events involved:

• Neural folds must fuse → form neural tube.

• Mesenchymal tissue must migrate → form skull bones.

• Paraxial mesoderm & neural crest cells provide skeletal elements.

• Failure of mesodermal ossification → persistent bony gap.

• Increased intracranial pressure during fetal development pushes meninges outward.

2.2 Sites of failure relevant to ENT:

• Frontonasal region

• Cribriform plate

• Foramen cecum

• Sphenoid bone defects

2.3 Mechanism of Herniation (ENT Pathogenesis):

• Defect in skull base → meninges bulge outward → form sac.

• This sac may protrude:

  • Externally on the face

  • Internally into nasal cavity/nasopharynx

  • At midline (most common)

2.4 Pressure Dynamics:

• Herniated sac communicates with subarachnoid space → CSF pulsations

• Increases risk of:

  • CSF leak

  • Meningitis

  • Enlargement of sac with crying/straining (positive Furstenberg sign)

---

3. Classification (ENT Must-Know Table)

---

4. Sites of Meningiocoele (ENT Important High-Yield)

Precise location decides symptoms + surgical approach.

4.1 Occipital (Most Common Globally)

• Not ENT-specific but included for classification completeness.

4.2 Fronto-nasal Region (Crucial for ENT)

• Herniates outward between forehead & nose

• Visible swelling at glabella/root of nose

4.3 Basal (Most Important for ENT Exams)

Bony defect → sac herniates internally, presenting as:

• Nasal cavity mass

• Nasopharyngeal mass

• Intranasal cyst-like lesion

Subtypes of Basal Lesions:

• Transethmoidal

• Transsphenoidal

• Sphenoethmoidal

• Frontosphenoidal

These appear as midline nasal masses — a classic ENT trap for misdiagnosis.

---

5. Etiology (Why It Happens)

5.1 Environmental + Maternal Factors

• Folic acid deficiency

• Maternal diabetes

• Hyperthermia in early pregnancy

• Alcohol, isotretinoin, anti-epileptics

• TORCH infections

5.2 Genetic Factors

• Chromosomal abnormalities

• Neural crest migration defects

• Familial recurrence in some cases

5.3 Mechanical/Developmental Factors

• Elevated fetal intracranial pressure

• Failure of mesodermal ossification

---

6. Clinical Features (ENT Ultra-Expanded)

Presentation depends on size, location, and degree of herniation.

6.1 Visible External Mass (Fronto-nasal Type)

• Midline swelling between eyes

• Soft, compressible

• Increases on straining/crying

• Reduces with pressure but re-expands

• May transilluminate

6.2 Intranasal Mass (Basal Type)

Appears as:

• Mass inside nasal cavity

• Can obstruct breathing → noisy breathing

• Neonate mouth breathing difficulty

• May cause:

  • Feeding problems

  • Respiratory distress

  • Recurrent nasal infections

6.3 Danger Features

• CSF rhinorrhea (clear watery discharge)

• Meningitis (high risk!)

• Recurrent episodes of fever, vomiting, irritability

---

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Professional) Otorhinolaryngology (ENT) Free Material

---

7. Special ENT Clinical Signs

7.1 Furstenberg Sign (VERY IMPORTANT VIVA)

• Mass enlarges when:

  • Baby cries

  • Valsalva maneuver

  • Compression of ipsilateral jugular vein

• Indicates intracranial connection.

7.2 Transillumination Test

• Positive → CSF-filled sac

• But not always reliable (brain tissue → negative)

7.3 Pulsations

• Small rhythmic pulsations may be visible

• Indicates CSF communication

---

8. Differential Diagnosis (ENT Must-Know Midline Nasal Masses)

NEVER biopsy a midline nasal mass without imaging — risk of fatal CSF leak.

8.1 Dermoid Cyst (Most common D/D)

• Often externally visible

• Hair, sebaceous secretions inside

• No pulsations

• Does not increase with crying

8.2 Glioma (Nasal Glial Heterotopia)

• Solid, firm

• Does not transilluminate

• No increase with crying

• Can be attached to dura or not

8.3 Hemangioma

• Compressible

• Bluish/red

• Bleeds easily

8.4 Encephalocele/Meningoencephalocele

• Contains brain tissue

• Similar presentation

8.5 Nasal Polyp (in older children)

• Soft, mobile

• Not pulsatile

• Not present at birth

8.6 Rhinosporidiosis / Other Masses (rare in neonates)

---

9. Investigations (ENT Radiology-Heavy Section)

9.1 MRI – Best for Soft Tissue + Intracranial Connection

Should ALWAYS be performed before any nasal procedure.

MRI provides:

• Extent of sac

• Presence of brain tissue

• Status of intracranial communication

• Content characterization (CSF vs solid)

9.2 CT Scan – Best for Bony Defects

Shows:

• Skull base defect location

• Size

• Thinning of cribriform plate

• Associated paranasal anomalies

9.3 Nasal Endoscopy (After Imaging Only!)

• Identifies intranasal mass

• Assesses attachment

• Evaluates obstruction

9.4 Ophthalmic & Neurological Evaluation

• Needed in frontonasal lesions

• Look for hypertelorism, strabismus

• Assess developmental delay

9.5 Avoid the following before imaging:

• Needle aspiration

• Biopsy

• Blind probing

(High risk of CSF leak → meningitis → death)

10. Management of Meningiocoele (Pure ENT + Neurosurgery Coordination)

Management is ALWAYS surgical, but the exact timing, approach, and priority depend on the size, location, presence of CSF leak, and intracranial extension.

10.1 General Principles of Management

• NEVER biopsy.

• NEVER aspirate.

• ALWAYS obtain CT + MRI before any intervention.

• ENT + Neurosurgery joint planning is essential.

• Protect airway in neonates with large intranasal lesions.

• Control of CSF leak is a priority.

---

11. Indications for Urgent Surgery

• CSF rhinorrhea

• Recurrent meningitis

• Respiratory obstruction (intranasal mass)

• Progressive enlargement of sac

• Pressure necrosis or ulceration of skin over sac

Delayed surgery may be performed if:

• Child is stable

• No CSF leak

• No infection

• Small lesion

---

12. Surgical Approaches (Ultra-Expanded ENT-Level)

Two main approaches depending on type & location:

A. Endoscopic Endonasal Approach (Preferred for Basal Lesions)

Modern ENT gold standard.

12.1 Steps in Endoscopic Repair

• Position child under general anesthesia

• Insert pediatric nasal endoscope

• Identify skull-base defect

• Reduce herniating sac (preserve viable tissue)

• Excise redundant sac if necessary

• Reconstruct skull base using multilayer technique

Techniques for Reconstruction

• Underlay graft (fascia lata, temporalis fascia, pericranium)

• Overlay graft (cartilage, bone)

• Nasoseptal flap (Haddad flap)

• Fibrin glue reinforcement

12.2 Advantages

• Minimally invasive

• Excellent visualization

• No external scars

• Lower morbidity

• Shorter hospital stay

• Ideal for transsphenoidal, sphenoethmoidal, transethmoidal lesions

12.3 Limitations

• Very small nasal cavity in neonates

• Technical difficulty

• Availability of pediatric endoscopic tools

• Need for advanced training

---

B. External/Craniofacial Approaches

Used for frontonasal, large, complex, or recurrent lesions.

12.4 Frontal Craniotomy

Neurosurgeon elevates frontal bone flap → ENT identifies sac entry → resects sac → reconstructs skull base.

12.5 Osteotomy-Based Approaches

• Transcranial frontoethmoidal repair

• Open rhinology approaches

• Combined craniofacial approach

12.6 Indications

• Large external swelling

• Brain tissue herniation (meningoencephalocele)

• Inadequate access endoscopically

• Suspicion of involvement of major vessels/dura

---

13. Skull Base Reconstruction (ENT Must-Know)

Stability of reconstruction determines recurrence, CSF leak risk, and long-term outcome.

13.1 Ideal Graft Materials

• Pericranium

• Fascia lata

• Septal cartilage

• Bone from vomer or crista galli

13.2 Goals of Reconstruction

• Seal defect

• Prevent CSF leak

• Restore barrier between nose and brain

• Minimize risk of infection

13.3 Layered Closure Concept

• Underlay (support)

• Overlay (seal)

• Biological glue (stability)

• Mucosal flap (vascularized healing)

---

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Professional) Otorhinolaryngology (ENT) Free Material

---

14. Postoperative Care (ENT Ultra-Detailed)

14.1 Monitoring

• Observe for CSF leak

• Watch for fever, neck stiffness (infection)

• Airway monitoring in infants

• Neurological assessment

14.2 Nasal Care

• No nasal suctioning for first few days

• Avoid nose blowing for 2–3 weeks

• Saline douching after 1 week

14.3 Antibiotics

• Broad spectrum initially

• Prevent meningitis

14.4 Lumbar Drain (Sometimes Used)

Indications:

• High-flow CSF leak

• Large defect

• Revision surgery

Purpose:

• Reduces intracranial pressure

• Facilitates graft healing

---

15. Complications of Meningiocoele + Surgery

15.1 Before Surgery

• Airway obstruction

• Feeding difficulty

• Meningitis

• Cosmetic deformity

• CSF leak

• Recurrent infections

15.2 During Surgery

• Bleeding

• Brain injury (in meningoencephalocele)

• Damage to olfactory bulbs

• Injury to nasal structures

• Anesthetic challenges in neonates

15.3 After Surgery

• Recurrence

• Persistent CSF leak

• Hyposmia/anosmia

• Infection

• Adhesions/synechiae

• Failure of skull-base graft

---

16. Prognosis (ENT Clinical Perspective)

16.1 Favorable Outcome

• Small meningiocoele

• No brain tissue involvement

• Early diagnosis

• Successful reconstruction

• No postoperative CSF leak

16.2 Unfavorable Outcome

• Meningoencephalocele

• Large skull-base defect

• CHARGE or other syndromes

• Delay in surgery

• Recurrent meningitis

---

17. High-Yield Tables for Revision & Viva

17.1 Differences Between Meningiocoele & Meningoencephalocele

---

17.2 Midline Nasal Mass Differentials (ENT Must-Memorize)

---

18. ENT Viva Questions (Long List for Exams)

Q1: What is the most important clinical sign of basal meningiocoele?

Furstenberg sign — enlargement of mass during crying/straining.

Q2: What is the first investigation for a midline nasal mass?

MRI (soft tissue + intracranial communication).

Q3: Why is biopsy contraindicated?

Risk of catastrophic CSF leak → meningitis → death.

Q4: What is the treatment of choice for basal meningiocoele?

Endoscopic endonasal repair + multilayer skull-base reconstruction.

Q5: What are complications if untreated?

Meningitis, aspiration, airway obstruction, facial deformity.

Q6: Which graft is most commonly used for skull base reconstruction?

Fascia lata / pericranium.

Q7: What sign differentiates dermoid cyst from meningiocoele?

Dermoid cyst does not enlarge on crying.

---

19. Radiological Features (ENT + Radiology Integration)

19.1 CT Findings

• Bony defect in cribriform plate/sphenoid

• Widening of nasal vault

• Thinned bone margins

• Associated sinus anomalies

19.2 MRI Findings

• CSF-filled sac

• T2 hyperintense lesion

• No brain parenchyma (meningiocoele)

• Clear connection to subarachnoid space

---

20. Surgical Anatomy Pearls (High-Yield ENT Points)

• Cribriform plate is the weakest part of anterior skull base.

• Foramen cecum is common site for frontonasal lesions.

• Olfactory fibers pass through cribriform plate → risk of anosmia after surgery.

• Ethmoid roof variation (Keros classification) influences surgical risk.

21. Advanced Surgical Considerations in Meningiocoele Repair

21.1 Pediatric Airway Challenges (ENT Anaesthesia Integration)

Neonates with intranasal or nasopharyngeal meningiocoele present a high-risk airway.

Why airway is difficult:

• Obstruction of nasal route → cannot pass nasal tube.

• Large mass may obstruct oropharynx when supine.

• Basal encephalocele may distort skull base → risk during intubation.

• Poor neck positioning tolerance.

Airway strategies:

• Gentle mask ventilation

• Avoid excessive pressure (risk of rupturing sac)

• Prefer orotracheal intubation

• Fiberoptic intubation if visualization difficult

• Availability of smaller-sized tubes for neonates

Post-intubation checks:

• Ensure no compression of sac

• Avoid nasal instrumentation

• Maintain neutral head position

---

21.2 Endoscopic Skull Base Repair – Technical Pearls

1. Exposure

• Decongestion using minimal vasoconstrictor

• Gentle suction to avoid rupturing sac

• Pediatric 2.7 mm endoscope

• Identify landmarks: middle turbinate, nasal septum, sphenoid ostium

2. Handling the Sac

• The sac should not be ruptured intentionally.

• If accidental rupture occurs:

  • Immediate suction

  • Maintain sterile field

  • Proceed with controlled reduction

3. Reducing the Sac

• Herniated meninges reduced back intracranially

• Brain tissue preserved if functional

• Non-functional tissue excised

4. Drilling the Bony Defect

• Diamond burr (low speed)

• Avoid overheating

• Enlarge margins smoothly

5. Reconstruction Strategy

• Start with underlay fascia

• Overlay cartilage or bone

• Apply fibrin glue

• Add vascularized flap if needed (superiorly based septal flap)

6. Avoiding Complications

• Do not over-drill → risk of dural tear

• Ensure no tension on graft

• Ensure complete sealing of defect

---

22. Case Scenarios (High-Yield ENT Exam Format)

Case 1: Newborn with Respiratory Distress

A 2-day-old baby presents with:

• Difficulty breathing

• Worse when feeding

• Midline intranasal mass

• Mass enlarges on crying

Diagnosis: Basal meningiocoele

Immediate step: MRI + airway stabilization

DO NOT: Attempt biopsy or suction

---

Case 2: 5-Year-Old with Swelling on Nasal Bridge

Symptoms:

• Midline forehead-nasal mass

• Transilluminates

• Pulsates

Diagnosis: Fronto-nasal meningiocoele

Management: Elective excision + craniofacial repair

---

Case 3: Neonate Undergoing Nasal Suctioning by Nurse → Sudden CSF Leak

A nurse mistakes the mass for mucous collection.

Complication: Sac rupture → CSF leak → risk of meningitis

Management:

• Start IV antibiotics

• Neurosurgical evaluation

• Repair of skull-base defect

---

Case 4: Misdiagnosed as Nasal Polyp

ENT resident removes “polyp” in OPD → brisk CSF leak.

Diagnosis: Basal meningoencephalocele

Error: Failure to perform imaging before removal

Lesson: NEVER TOUCH a midline nasal mass before imaging

---

23. ENT OSPE Points (Exam-Scoring Section)

Station: Midline Nasal Mass in Neonate

Examiner expects the candidate to say:

• Most dangerous diagnosis = encephalocele/meningiocoele

• Do NOT biopsy

• Order MRI

• Manage airway

• ENT + neurosurgery joint repair

• Furstenberg sign positive

• High risk of meningitis

Station: Radiology Interpretation

CT: Skull base defect
MRI: CSF sac

Candidate must identify:

• Defect site

• Communication with intracranial space

• Presence/absence of brain tissue

---

24. Relationship Between Meningiocoele & CSF Rhinorrhea

Meningiocoele often presents with intermittent clear watery discharge in infants.

Features suggesting CSF origin:

• Continuous or positional

• Increases with bending forward

• Watery, non-viscous

• Positive for β2-transferrin (confirmatory test)

Risks:

• Ascending infections → meningitis

• Failure to thrive

• Dangerous dehydration in neonates

---

25. Microanatomy & Histology Correlations

25.1 Histology of the Sac

• Sac wall composed of dura mater + arachnoid

• Lined internally by arachnoid cells

• CSF within cavity

• NO neural tissue in meningiocoele

25.2 If brain tissue found → re-label as meningoencephalocele

25.3 Histology of Surrounding Nasal Structures

• Ciliated pseudostratified columnar epithelium

• Goblet cells

• Submucosal glands

• May be displaced or thinned due to mass pressure

---

26. Associated Congenital Anomalies

• Hydrocephalus

• Cleft palate

• Hypertelorism

• Craniosynostosis

• Chiari malformations

• Corpus callosum defects

---

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Professional) Otorhinolaryngology (ENT) Free Material

---

27. Prognostic Factors

Good Prognosis When:

• Isolated meningiocoele (no brain tissue)

• Small defect

• Early repair

• No CSF leak

• No syndromic association

Poor Prognosis When:

• Meningoencephalocele

• Large skull-base defect

• Delayed management

• Associated hydrocephalus

• Incomplete repair or recurrence

---

28. ENT Surgeon “Red Flags” – Must Not Miss

• Midline nasal mass → never a simple polyp

• Avoid suctioning or pressure on mass

• Avoid nasal airways in neonates

• Always evaluate for CHARGE syndrome

• Look for pulsations & expansion during crying

• Confirm absence of brain tissue before reducing lesion

---

29. MCQs (Exam-Style)

MCQ 1

A neonatal midline nasal mass that enlarges with crying is most likely:
A. Dermoid cyst
B. Hemangioma
C. Meningiocoele
D. Nasal polyp

Correct Answer: C

---

MCQ 2

Which investigation is best to confirm intracranial extension?
A. Ultrasound
B. CT scan
C. MRI
D. Diagnostic nasal endoscopy

Correct Answer: MRI

---

MCQ 3

Which is contraindicated in evaluation of meningiocoele?
A. MRI
B. CT scan
C. Nasal endoscopy
D. Biopsy

Correct Answer: D

---

MCQ 4

Which sign indicates communication with intracranial cavity?
A. Blanching on pressure
B. Movement with deglutition
C. Furstenberg sign
D. No change with crying

Correct Answer: C

---

30. High-Yield Revision Summary (ENT 1-Minute Notes)

• Failure of neural tube closure → skull base defect

• Midline nasal mass in neonate = meningiocoele until proven otherwise

• Furstenberg sign positive

• MRI for soft tissue + CT for bone

• Never biopsy

• Endoscopic repair preferred

• Multilayer reconstruction prevents CSF leak

• Associated with CHARGE, hydrocephalus, clefts

• Major complication = meningitis

• Prognosis excellent if no brain tissue herniation