Electrolytic, chemical, or balloon-compressive lesions of the gasserian ganglion can be made via a percutaneous stereotaxically positioned needle. Occasionally, a last resort to relieve intractable pain is resection of the 5th nerve fibers between the gasserian ganglion and the brain stem. Bell's Palsy Unilateral facial paralysis of sudden onset and unknown cause. The mechanism presumably involves swelling of the nerve due to immune or viral disease, with ischemia and compression of the facial nerve in the narrow confines of its course through the temporal bone. Pain behind the ear may precede facial weakness.
Weakness develops within hours, sometimes to complete paralysis.
The affected side becomes flat and expressionless, but patients may complain instead about the seemingly twisted intact side. In severe cases, the palpebral fissure widens, and the eye does not close. The patient may complain of a numb or heavy feeling in the face, but no sensory loss is demonstrable. A proximal lesion may affect salivation, taste, and lacrimation and may cause hyperacusis. Skull x-rays and CT and MRI scans are obtained when the diagnosis is in doubt.