---
title: "Inside out VS Outside in Mastoidectomy"
description: "Key differences between Inside out and Outside in Mastoidectomy - ideal for MBBS and ENT students."
source: "The ENT Resident"
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 - ideal for MBBS and ENT students. 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 |

---

## About This Note

This note on Inside out VS Outside in Mastoidectomy is one of the free ENT study notes published by The ENT Resident. It is free to read on the website, and it is paired with a full video lecture on YouTube.

This note is categorized under [Otology](https://www.theentresident.com/ent-notes-lectures/category/otology.md), [Surgery](https://www.theentresident.com/ent-notes-lectures/category/surgery.md), and [Differences Tables in ENT](https://www.theentresident.com/ent-notes-lectures/category/differences-tables-in-ent.md). Each category page lists all the free ENT notes on that topic.

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## Related ENT Notes & Lectures

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#### Differences Tables in ENT

- [Acute Mastoiditis VS Furunculosis](https://www.theentresident.com/ent-notes-lectures/acute-mastoiditis-furunculosis.md)
- [Adult vs Pediatric Larynx](https://www.theentresident.com/ent-notes-lectures/adult-vs-pediatric-larynx.md)
- [Antrochoanal Polyp vs Ethmoidal Polyp](https://www.theentresident.com/ent-notes-lectures/antrochoanal-vs-ethmoidal-polyp.md)
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- [Inner Ear fluids - Perilymph and Endolymph](https://www.theentresident.com/ent-notes-lectures/perilymph-endolymph.md)
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