See 10.5, Isolated Third Cranial Nerve Palsy.

(See Figures 10.6.1 and 10.6.2.)

Figure 10.6.1: Aberrant regeneration of right third cranial nerve showing right-sided ptosis in primary gaze.

Figure 10.6.2: Aberrant regeneration of right third cranial nerve showing right upper eyelid retraction on attempted left gaze.

The most common signs of aberrant third cranial nerve regeneration include the following:

• Eyelid-gaze dyskinesis: Elevation of involved eyelid on downgaze (Pseudo-von Graefe sign) or adduction.

• Pupil-gaze dyskinesis: Pupil constricts on downgaze or adduction.

• Other signs may include limitation of elevation and depression of eye, adduction of involved eye on attempted elevation or depression, absent optokinetic response, or pupillary light-near dissociation.

Thought to result from misdirection of the third cranial nerve fibers from their original destination  to alternate third cranial nerve controlled muscles (e.g., inferior rectus to the pupil).

• Aberrancy from congenital third cranial nerve palsies: Can be seen in up to two-thirds of these patients.

• Aberrancy from prior acquired third cranial nerve palsies: Seen most often in patients recovering from third cranial nerve damage by trauma or compression by a posterior communicating artery aneurysm.

• Primary aberrant regeneration: A term used to describe the presence of aberrant regeneration in a patient who has no history of a third cranial nerve palsy. Usually indicates the presence of a progressively enlarging parasellar lesion such as a carotid aneurysm or meningioma within the cavernous sinus.

1. Aberrancy from congenital: None. Document workup of prior congenital third cranial nerve palsy.

2. Aberrancy from acquired: See 10.5, Isolated Third Cranial Nerve Palsy. Document workup of prior acquired third cranial nerve palsy if previously obtained.

3. Primary aberrancy: All patients must undergo neuroimaging to rule out slowly compressive lesion or aneurysm.

NOTE Ischemic third cranial nerve palsies DO NOT produce aberrancy. If aberrant regeneration develops in a presumed ischemic palsy, neuroimaging should be performed.

1. Treat the underlying disorder.

2. Consider strabismus surgery if significant symptoms are present.

1. Aberrancy from congenital: Routine.

2. Aberrancy from acquired: As per the underlying disorder identified in the workup.

3. Primary aberrancy: As per neuroimaging and clinical examination findings. Patients are instructed to return immediately for any changes (e.g., ptosis, diplopia, sensory abnormality).