Trigeminal Neuralgia Refractory to Medical Therapy
Severe facial pain attacks despite maximal drug therapy.
- Carbamazepine: First-line drug (often loses effect over time)
- Paroxysmal: Pain type (electric shock-like attacks)
- Seconds: Attack duration (to ~2 minutes each)
- ~30%: Medical failure rate (become drug-refractory)
Why pain becomes refractory
Drug tolerance and side effects limit long-term dosing.
Trigger zones and attacks
Light touch, chewing, or wind can trigger attacks.
When surgery is considered
Refractory or intolerant patients are referred for imaging.
MRI Identification of the Neurovascular Conflict
Thin-slice MRI localizes the offending vessel precisely.
- SCA: Most common vessel (superior cerebellar artery)
- CISS/FIESTA: Imaging sequence (high-res cisternographic MRI)
- Root entry zone: Conflict site (nerve exits pons)
- ~90%: MRI sensitivity (for detecting compression)
Locating the compression
Thin MRI slices trace the nerve through the cistern.
Vessel identification
Arterial or venous loops are distinguished on imaging.
Surgical planning
Findings guide the craniotomy approach and trajectory.
Retrosigmoid Craniotomy to the Cerebellopontine Angle
A small posterior opening provides access to the nerve.
- Retrosigmoid: Approach (behind the sigmoid sinus)
- ~4 cm: Incision size (small keyhole craniotomy)
- General: Anesthesia (microsurgical technique)
- 2–3 hrs: Typical duration (under the operating microscope)
Opening the skull
A small bone window is made behind the ear.
Reaching the CPA
Gentle cerebellar retraction reveals the nerve-vessel conflict.
Microscopic confirmation
The surgeon visually confirms the compressing vessel.
Teflon Pad Placement Between Vessel and Nerve
A soft implant permanently separates artery from nerve.
- Teflon felt: Implant material (inert, non-absorbable)
- Interposition: Technique (pad cushions the conflict)
- ~90%: Immediate relief (of patients pain-free at wake)
- Low: Complication rate (hearing loss, CSF leak rare)
Mobilizing the vessel
The artery loop is carefully lifted off the nerve.
Inserting the pad
Teflon felt is wedged between vessel and nerve root.
Confirming decompression
The nerve is inspected to confirm full relief.
Pain Relief and Long-Term Recurrence Risk
Most patients wake pain-free; some relapse over years.
- ~90%: Immediate success (pain-free at discharge)
- ~80%: 5-year durability (remain pain-free)
- ~20%: 10-year recurrence (cumulative relapse risk)
- Low: Reoperation rate (if recurrence occurs)
Immediate postoperative relief
Many patients notice relief upon waking from anesthesia.
Durability over time
Pad migration or scarring can allow slow recurrence.
Long-term monitoring
Follow-up tracks recurrence risk across the years.