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11. FLOW CHARTS

FLOWCHART 1: Indications and Pathway to Simple Mastoidectomy

                    ACUTE OTITIS MEDIA
                           │
               ┌───────────┴───────────┐
          No complications        Complications develop
               │                       │
         Antibiotics              ASSESS TYPE
         (resolves)               │           │
                            Mastoiditis   Intracranial
                                 │        complications
                    ┌────────────┤
              Responds to    Coalescent/
              antibiotics    Subperiosteal
                    │        abscess formed
                Observe           │
                            SIMPLE MASTOIDECTOMY
                            + IV Antibiotics
                                  │
                    ┌─────────────┼─────────────┐
              Resolves      Persists: check    Chol-
              (cure)        for cholesteatoma  esteatoma
                                  │            → Modified
                            Re-evaluate        Radical /
                                               Canal wall
                                               down

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FLOWCHART 2: Surgical Steps — Simple Mastoidectomy

┌─────────────────────────────────────────────────┐
│  PRE-OPERATIVE PREPARATION                      │
│  (Consent, GA, positioning, monitoring)         │
└──────────────────┬──────────────────────────────┘
                   ↓
┌─────────────────────────────────────────────────┐
│  POSTAURICULAR INCISION                         │
│  (1 cm posterior to postauricular sulcus)       │
└──────────────────┬──────────────────────────────┘
                   ↓
┌─────────────────────────────────────────────────┐
│  PERIOSTEAL ELEVATION                           │
│  Expose mastoid cortex, MacEwen's triangle,     │
│  posterior EAC, temporal line, mastoid tip      │
└──────────────────┬──────────────────────────────┘
                   ↓
┌─────────────────────────────────────────────────┐
│  CORTEX REMOVAL                                 │
│  Large cutting burr → MacEwen's triangle        │
│  (Saucerization — wide approach)                │
└──────────────────┬──────────────────────────────┘
                   ↓
┌─────────────────────────────────────────────────┐
│  IDENTIFY ANTRUM                                │
│  Follow temporal line → Tegmen                  │
│  Blue-line lateral semicircular canal (LSCC)    │
│  Antrum lies anterosuperior to LSCC             │
│  Verify communication with aditus               │
└──────────────────┬──────────────────────────────┘
                   ↓
┌─────────────────────────────────────────────────┐
│  EXENTERATE ALL MASTOID AIR CELLS               │
│  Tip, tegmental, retrofacial, perilabyrinthine, │
│  sinus, periantral cells                        │
└──────────────────┬──────────────────────────────┘
                   ↓
┌─────────────────────────────────────────────────┐
│  FINAL CHECK                                    │
│  Tegmen intact? Sigmoid exposed safely?         │
│  LSCC preserved? PCW intact? Aditus open?       │
│  Facial nerve safe? No cholesteatoma missed?    │
└──────────────────┬──────────────────────────────┘
                   ↓
┌─────────────────────────────────────────────────┐
│  WOUND CLOSURE                                  │
│  Haemostasis → drain (if infected) →            │
│  periosteum → subcutaneous → skin sutures →     │
│  pressure dressing                              │
└─────────────────────────────────────────────────┘

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FLOWCHART 3: Complications — Recognition and Management

INTRAOPERATIVE COMPLICATIONS
        │
        ├── Facial nerve injury
        │         → Immediate nerve monitoring alert
        │         → Stop drilling, identify nerve
        │         → If cut: immediate repair/grafting
        │
        ├── Sigmoid sinus tear
        │         → Pressure with Gelfoam/Surgicel
        │         → Bone wax over sinus
        │
        ├── Dural tear / CSF leak
        │         → Pack with fat graft/temporalis fascia
        │         → Neurosurgery consult if severe
        │
        └── Entry into semicircular canal
                  → Immediate stop, avoid suction
                  → Pack with fat (SHL inevitable)

POST-OPERATIVE COMPLICATIONS
        │
        ├── Wound infection → Antibiotics, drain
        ├── Facial paresis → Steroids, monitoring
        ├── Sensorineural hearing loss → Evaluate PTA
        ├── CSF otorrhea → Conservative/surgical repair
        └── Recurrent/residual disease → Re-exploration

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12. COMPLICATIONS

Intraoperative

Early Post-operative

• Wound infection and hematoma
• Post-operative facial palsy (usually neuropraxia → steroids)
• Vertigo (labyrinthine irritation)
• Tinnitus

Late Post-operative

• Recurrent mastoiditis
• Persistent otorrhea
• Sensorineural hearing loss (SNHL)
• Meningitis
• Residual/recurrent cholesteatoma (if combined with tympanoplasty)
• Keloid scar

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13. POST-OPERATIVE CARE

• Ear drops: Topical antibiotic + steroid drops post-operatively
• Avoid water entry for 6 weeks
• Avoid nose blowing for 2 weeks

---

14. DIFFERENCES: SIMPLE vs. MODIFIED RADICAL vs. RADICAL MASTOIDECTOMY

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15. MODIFICATIONS AND RELATED PROCEDURES

15.1 Combined Approach Tympanoplasty (CAT)

• Simple mastoidectomy + posterior tympanotomy + tympanoplasty
• Canal wall up (CWU) technique
• Preserves EAC anatomy while clearing mastoid disease
• Two-stage procedure often needed to detect residual cholesteatoma

15.2 Posterior Tympanotomy

• Extension of simple mastoidectomy
• Opens facial recess (between facial nerve, chorda tympani, and EAC)
• Access for cochlear implant insertion
• Access for posterior tympanum

15.3 Endolymphatic Sac Surgery (Decompression/Shunt)

• Simple mastoidectomy is the approach
• Indicated in Meniere's disease refractory to medical treatment

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16. RECENT ADVANCES (RGUHS-Relevant)

16.1 Endoscopic-Assisted Mastoidectomy

• Combines microscopic mastoidectomy with endoscopic visualization of difficult corners
• Better illumination of sinus tympani, facial recess, and protympanum
• Reduces need for canal wall down in selected cases
• (El-Anwar et al., 2015; Bennett et al., 2016)

16.2 Image-Guided Surgery (Navigation)

• CT/MRI-based intraoperative navigation
• Reduces risk to facial nerve and sigmoid sinus
• Especially useful in revision surgery and obliterated mastoids
• Medtronic NIM-Response® and Stryker Navigation systems in common use

16.3 Intraoperative Facial Nerve Monitoring

• Continuous EMG-based monitoring (NIM-3 system)
• Significantly reduces incidence of permanent facial nerve injury
• Now considered standard of care in mastoid surgery (AAO-HNS Guidelines)

16.4 Powered Irrigation Systems

• Constant saline irrigation integrated with drill (Medtronic Midas Rex)
• Prevents thermal injury to labyrinth and nerve
• Reduces bone dust and improves visualization

16.5 Laser-Assisted Mastoidectomy

• CO₂ or KTP laser for precise bone removal near critical structures
• Useful near facial nerve and semicircular canals
• Limited by cost and availability (Jovanovic et al., 2004)

16.6 Robotic Mastoidectomy

• Robotic drill systems with pre-programmed CT-guided trajectories
• Achieves sub-millimeter accuracy
• Prototype systems (RobOtol®, Helix Otosurgery Robot) in clinical trials
• (Williamson et al., 2015; Labadie et al., 2012)

16.7 3D Temporal Bone Simulation & Training

• Virtual reality mastoidectomy simulators (Voxel-Man® TempoSurg)
• Allows resident training without patient risk
• Validated tool for competency assessment (Alrwaily et al., 2017)

16.8 Piezoelectric Bone Surgery (Piezosurgery)

• Ultrasonic bone cutting devices
• Selective — cuts bone but spares soft tissue (nerves, dura, vessels)
• Applications in difficult mastoid dissections (Schlee et al., 2014)

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17. TEXTBOOK PERSPECTIVES SUMMARY

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18. MNEMONIC AIDS

• Tegmen = roof
• Sigmoid sinus = posterior
• Lateral semicircular canal = medial guide
• Facial nerve = medial danger
• Digastric ridge = inferior

• Sinus tip
• Tegmental
• Retrofacial
• Perilabyrinthine
• Tip
• Periantral

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19. VIVA/EXAM POINTS (RGUHS Focus)

1. Schwartze's operation = Simple/Cortical mastoidectomy (1873)
2. MacEwen's triangle is the surface marking of the mastoid antrum
3. Körner's septum = petrosquamous suture; surgical pitfall
4. Antrum is 1.5–2 cm deep to the surface in adults; just 1.25 cm at birth
5. Lateral semicircular canal = single most important surgical landmark
6. Posterior canal wall is PRESERVED in simple mastoidectomy — key difference from radical
7. Three dangerous structures: Dura (tegmen), Sigmoid sinus, Facial nerve
8. Sclerotic mastoid = most difficult type to operate on
9. Bezold's abscess = pus tracking below digastric muscle into neck → mastoidectomy + drainage
10. Minimum 48–72 hours of IV antibiotics before declaring failure and proceeding to surgery

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20. SUMMARY TABLE

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References

1. Scott Brown's Otorhinolaryngology, Head & Neck Surgery, 8th Edition — Chapter on Mastoid Surgery
2. Cummings Otolaryngology: Head and Neck Surgery, 7th Edition — Chapter 139 (Mastoid Surgery)
3. Stell and Maran's Head and Neck Surgery — Temporal Bone Section
4. Zakir Hussain — Textbook of ENT & Head and Neck Surgery
5. Dhingra PL — Diseases of Ear, Nose & Throat, 7th Edition
6. Hazarika P — Textbook of Ear, Nose & Throat, 4th Edition
7. Bailey & Love's Short Practice of Surgery, 28th Edition, p. 774
8. Williamson RA et al. — "Robotic mastoidectomy" — Laryngoscope, 2015
9. El-Anwar MW et al. — "Endoscope-assisted cortical mastoidectomy" — Eur Arch ORL, 2015
10. AAO-HNS Clinical Practice Guidelines — Tympanostomy Tubes & Mastoidectomy, 2020

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