---
title: "Inside out VS Outside in Mastoidectomy"
description: "Key differences between Inside out and Outside in Mastoidectomy."
source: "The ENT Resident"
author: "Dr. Mausumi Das"
canonical_url: "https://www.theentresident.com/ent-notes-lectures/inside-out-outside-in-mastoidectomy"
categories: ["Otology", "Surgery", "Differences Tables in ENT"]
video: "https://www.youtube.com/watch?v=zR5m6jt5g7I"
image: "https://media.theentresident.com/og-images/inside-out-outside-in-mastoidectomy.png"
---

# Inside out VS Outside in Mastoidectomy

Key differences between Inside out and Outside in Mastoidectomy. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=zR5m6jt5g7I

## 🦻Inside out Mastoidectomy VS Outside in Mastoidectomy

| Topic | Inside-out Mastoidectomy | Outside-in Mastoidectomy |
| --- | --- | --- |
| **Definition** | Start from the **middle ear/attic** and work outward to aditus, antrum and mastoid - selective, disease-directed removal. | Start from the **mastoid cortex** and work inward to antrum, aditus and middle ear - wide exenteration of mastoid cells. |
| **Approach / Sequence** | Tympanomeatal flap → atticotomy → clear attic → aditus → antrum → mastoid air cells (from inside → out). | Post-auricular incision → expose mastoid cortex → drill mastoid air cells → reach antrum → widen aditus/attic → disease clearance → tympanoplasty. |
| **Extent of mastoid clearance** | **Selective** - remove only diseased cells; preserve healthy mastoid | **Extensive** - exenterate most accessible mastoid air cells (wide clearance) |
| **Typical indications** | - Isolated attic cholesteatoma<br />- Limited pediatric cholesteatoma<br />- Combined approach tympanoplasty when disease centered in attic/epitympanum | - Diffuse mastoid disease<br />- Acute/coalescent mastoiditis<br />- Cases where mastoid is the primary site of disease<br />- When landmarks are intact and wide access needed |
| **Skill level required** | High - technically demanding; requires detailed anatomical knowledge and experienced surgeon. | Lower - landmark-based and systematic; suitable for trainees / more predictable. |
| **Main advantages** | - Targeted/disease-directed clearance<br />- Less bone removal → smaller cavity<br />- Potentially shorter operative time (if surgeon experienced)<br />- Good for attic-predominant pediatric disease | - Systematic, landmark-based (easier to teach / learn)<br />- Wide exposure → lower chance of hidden residual disease<br />- Good for diffuse mastoid involvement and acute mastoiditis |
| **Main disadvantages / risks** | - Higher technical difficulty<br />- Risk of missing disease in hidden recesses (retrofacial, tip, retrosigmoid cells) if not meticulous<br />- Landmarks may not be encountered in usual order | - More bone removed (larger cavity)<br />- Longer operating time<br />- Risk of over-drilling normal mastoid where unnecessary<br />- Less efficient for attic-predominant disease |

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## About This Note

This free ENT note on Inside out VS Outside in Mastoidectomy was written by Dr. Mausumi Das and is paired with a corresponding video lecture.

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## Related Notes by Category

- Otology: https://www.theentresident.com/ent-notes-lectures/category/otology.md
- Surgery: https://www.theentresident.com/ent-notes-lectures/category/surgery.md
- Differences Tables in ENT: https://www.theentresident.com/ent-notes-lectures/category/differences-tables-in-ent.md

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