A vestibular schwannoma, also called an acoustic neuroma, is a benign tumor that develops on the vestibulocochlear nerve (cranial nerve VIII) — the nerve responsible for hearing and balance.
While these tumors grow slowly, if left untreated, they can enlarge enough to compress the brainstem, facial nerve, and cerebrospinal fluid pathways, occasionally leading to hydrocephalus (fluid buildup in the brain). Modern diagnosis and microsurgical or radiosurgical techniques now allow safe, hearing-preserving management in most patients.
Symptoms
Vestibular schwannomas often cause subtle, gradual symptoms that may be overlooked in the early stages. Common findings include:
- Gradual hearing loss, usually on one side (the most frequent symptom)
- Tinnitus (ringing or buzzing in the ear)
- Unsteadiness or imbalance, especially in dark environments
- Fullness or pressure in one ear
- Facial numbness, tingling, or weakness from nerve compression
- In large or fast-growing tumors: headache, double vision, or difficulty walking due to brainstem compression
- Headache, blurred vision, or double vision due to brainstem pressure
- Signs of hydrocephalus in untreated or large tumors — such as nausea, vomiting, gait disturbance, and cognitive slowing
Diagnosis
Diagnosis begins with audiometry to measure hearing loss and MRI with contrast to visualize the tumor.
Small tumors are often discovered incidentally during imaging for unrelated issues.
Additional tests such as brainstem auditory evoked potentials (BAEP) may help evaluate nerve function before and after treatment.
Treatment Options
1. Observation (“Wait and Scan”)
Small, slow-growing tumors without significant symptoms can be safely monitored with MRI every 6–12 months. This is especially suitable for elderly patients or those with minimal hearing loss.
2. Microsurgical Removal
For symptomatic or enlarging tumors, microsurgical resection offers the best long-term control.
Surgical approaches include:
- Retrosigmoid (suboccipital): for hearing preservation and larger tumors
- Translabyrinthine: for complete removal when hearing is already lost
- Middle fossa: for small, intracanalicular tumors with useful hearing
Advanced intraoperative facial and auditory nerve monitoring and neuronavigation minimize complications and preserve facial movement and hearing whenever possible.
3. Stereotactic Radiosurgery (Gamma Knife / CyberKnife)
For small- to medium-sized tumors, single-session radiosurgery can stop tumor growth with minimal risk and no incision.
It’s a preferred option for patients unfit for surgery or wishing to avoid open procedures.
Recovery & Follow-Up
Most patients recover within a few days to a week after microsurgery.
Temporary dizziness or imbalance is common but improves with vestibular rehabilitation.
Follow-up MRIs are performed regularly to ensure no regrowth after surgery or radiosurgery.
Facial nerve and hearing function are monitored long-term for optimal outcomes.
If hydrocephalus was present preoperatively, CSF shunting or ventricular drainage may be needed, but most cases improve after tumor removal.
Regular MRI follow-up ensures early detection of regrowth or CSF flow problems.
When to See a Neurosurgeon
If you experience one-sided hearing loss, ringing in one ear, imbalance, or new headaches with unsteadiness or vomiting, it’s essential to seek evaluation.
Early diagnosis allows safer treatment and prevents complications such as hydrocephalus or brainstem compression.