Endolymphatic Shunt Surgery: Success Metrics, Outcomes, and Long-Term Perspective

Endolymphatic Shunt Surgery: Defining Success

Endolymphatic shunt (or decompression) surgery treats endolymphatic hydrops (Ménière’s disease) by relieving inner ear fluid pressure.

Success Criteria (Multidimensional)

Domain	Measures	Success Threshold
Symptom Control	Vertigo frequency/severity (Dizziness Handicap Inventory), tinnitus, aural fullness	≥70% reduction in vertigo spells; patient-reported “much improved”
Audiometric	Pure-tone averages (low frequencies 250–1000 Hz), speech discrimination	Stabilization or ≥10 dB improvement in PTA
Vestibular Function	VNG/ENG (caloric asymmetry), vHIT, VEMP	Reduced canal paresis; normalized VEMP thresholds
Quality of Life	SF-36, EQ-5D, disease-specific QoL scales	Clinically meaningful improvement (>0.5 SD)

Outcome Reality

• Vertigo control: 60–80% “substantial improvement” at 1–2 years; declines to 50–60% at 5–10 years.
• Hearing: Stabilizes in ~50%; improves in 15–20%; worsens in 10–15%.
• Complications: CSF leak (1–3%), hearing loss (<1%), facial nerve injury (rare), wound infection.

Long-Term Perspective

Success is not binary. Shared decision-making should weigh probabilistic outcomes, alternatives (gentamicin, vestibular nerve section, lifestyle), and patient values.