If you are following a patient after surgical resection of a vestibular schwannoma (e.g., acoustic neuroma), you must vigilantly watch for several crucial symptoms or complications, particularly in the first few weeks after surgery. Similar recommendations can be made for most patients who have undergone brain surgery, particularly for disorders in the posterior fossa.
When following a patient after a resection, watch for seven signs of vestibular schwannoma surgery complications:
- Cerebrospinal fluid leakage
- Bacterial meningitis
- Aseptic meningitis
- Vertigo and unsteadiness
- Hearing loss
- Facial palsy and numbness
Cerebrospinal fluid leakage
Cerebrospinal fluid (CSF) leakage is not uncommon after vestibular schwannoma resection. But, CSF leakage puts the patient at risk for bacterial meningitis; if CSF can leak out, bacteria can leak in.
The leakage may occur from the resection wound, which will be obvious by clear or blood-tinged clear fluid leaking from the incision line. Often, the wound will be bulging.
On the other hand, CSF can also make it to the throat and nose through the mastoid air cells and the eustachian tubes. In this case, the patient may notice a persistent postnasal drip or a salty taste in their mouth. They may also notice clear fluid dripping from their nose, particularly if they lean forward.
Often, the leak is so robust that patients can demonstrate it and you can catch several milliliters of the fluid in a tube if given some time. Notify the surgeons right away if you suspect a persistent leak.
Patients experiencing bacterial meningitis may present with a headache, stiff neck, and / or fever. Bacterial meningitis can be secondary to a CSF leak or from contamination during surgery.
If you suspect postoperative bacterial meningitis, obtain a computed tomography (CT) scan to rule out a large intracranial collection of blood or fluid, and then move on to a lumbar puncture. If there is a large collection of blood or fluid compressing brain tissue, the lumbar puncture could precipitate catastrophic herniation and should not be performed. Under these circumstances, contact the neurosurgeons right away.
Once the CSF has been collected, initiate presumptive antibiotics right away. Generally, organisms to be covered should include Staphylococcus, Streptococcus pneumoniae, other Streptococcus species, gram-negative bacteria, and anaerobic bacteria. You may want to check with your infectious disease teams for their current recommendations on medications for bacterial meningitis.
Patients with aseptic meningitis may present with a severe headache and a stiff neck. Fever is possible but tends to be low grade. Aseptic meningitis is not an uncommon phenomenon and is related to blood and bone dust being spilled into the CSF spaces during surgery.
Patients with aseptic meningitis feel miserable and appear toxic. A lumbar puncture may need to be performed to rule out bacterial meningitis. The CSF white cell count may be elevated, but generally not as much as bacterial meningitis cases. As well, CSF glucose tends to be not as low as bacterial meningitis cases.
Antibiotics may need to be initiated until the CSF cultures prove negative. Aseptic meningitis tends to respond nicely to a short run of corticosteroids such as 2–4 mg of dexamethasone every 6–8 hours for a few days, followed by a rapid taper.
Vertigo and unsteadiness
Watch postoperative patients for profound vertigo and unsteadiness. This is usually self-limited and can be helped with some physical therapy. One way or another, it tends to improve over several weeks.
Be aware that many (or most) patients with moderate to large tumors will have complete hearing loss in their affected ear. If the hearing is lost in the affected ear postoperatively, it cannot be restored. However, special hearing aids can be prescribed that route sound to the remaining functional ear.
Facial palsy and numbness
Facial palsy occurs in 25–50% of patients after a large vestibular schwannoma resection. This will need to be followed by the surgeons and other specialists such as the neuro-otologists and plastic surgeons.
Facial electromyography (EMG) may help determine the recovery probability. Reanimation procedures can be considered if the chance of improvement is minimal to none. These procedures include nerve transfers or (more commonly) facial muscle transfers.
Facial numbness may also occur and is particularly a problem if the corneal reflex is lost. A loss of the corneal reflex puts the patient at a higher risk of corneal abrasion and ulceration. This can be further compounded by facial nerve palsy, where the patient may not be able to adequately shut their eye.
If a patient has lost their corneal reflex or has facial palsy where they cannot adequately shut the affected eye, consult ophthalmology for management. This may involve temporary patching or sutured closing of the affected eye, eventual placement of weights in the eyelid, or reanimation procedures.
Hydrocephalus may be present immediately after surgery, but can also creep up over the first few months post-surgery. It may present with increasing headaches and cognitive difficulties, but it is more likely to present with a bulging surgical wound or leakage from the wound.
If the patient has hydrocephalus, refer them back to their surgeons right away. Early hydrocephalus will sometimes resolve with steroids and CSF drainage. Delayed hydrocephalus usually will require surgical management which typically involves the placement of a ventriculoperitoneal shunt.
Vestibular schwannoma surgery, like many other major brain surgeries, is replete with a significant risk of profound neurological injury, including brainstem stroke, hemiparesis, facial palsy, and multiple cranial nerve palsy. The risk is also high for downstream complications such as CSF leak, infection, aseptic meningitis, and hydrocephalus.
However, vestibular schwannomas are benign tumors, and if managed appropriately can carry a good long-term prognosis. A resected tumor should be followed yearly with magnetic resonance imaging (MRI) of the region. Afterward, the frequency of follow-up MRI can be spaced out over time.
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- Adewumi, D, Agazzi, S, Asher, AL, et al. 2017. Guidelines on the management of patients with vestibular schwannoma. Congress of Neurological Surgeons. https://www.cns.org/
- Congress of Neurological Surgeons. 2020. Vestibular schwannoma guidelines. Congress of Neurological Surgeons. https://www.cns.org/