13.3.2 Painful nervus intermedius neuropathy

Identification: Male patient, 52 years old, with chronic ear pain for 14 months following vestibular schwannoma surgery.

History of Illness:
Context: Previous surgery: Resection of schwannoma of the internal acoustic meatus (via retrosigmoid approach) 16 months ago

Symptom onset: 2 months post-operative

Characteristics of Pain:
Location:

Deep external auditory canal (80%)
Retroauricular region (20%)

Type:

Continuous pain: Burning (5-7/10 VAS)
Exacerbations: Lancinating paroxysms (8-9/10), 3-10 episodes/day

Neuropathic phenomena:

Allodynia with hearing aid use
Painful hyperacusis
Hypoesthesia in the tragus

Physical/Neurological Examination:
Otological Assessment:

Hypoesthesia to fine touch in the acoustic meatus
Decreased ipsilateral stapedial reflex

Sensory Tests:

Mechanical allodynia (von Frey brush 4.31)
Hyperpathia to percussion of the mastoid process

Surgical Sequelae:

Peripheral facial paralysis grade II (House-Brackmann)

Additional Examinations:
3T Magnetic Resonance Imaging (FIESTA):

Post-surgical fibrosis along the intermediate nerve pathway
Absence of tumor recurrence

Electrophysiology:

Diagnostic block of the auriculotemporal nerve → partial pain relief

Audiometry:

Moderate ipsilateral sensorineural hearing loss