NANOSNET

Thanks for all the suggestions. 

I reviewed the eye movement recording again. She had very subtle left-beating nystagmus on primary gaze (more intense when I checked her pupil in darkness), worse on left gaze and down gaze, with a frequency of 4 Hz . Subtle on upgaze. No nystagmus on right gaze. I'm not sure about the rotational component. Will order a VNG.

She had reported numbness of the left face, which is consistent with V damage. 

This is a comprehensive review of neuro-ophthalmic complications of acoustic neuroma resection. I don't know if ABI implantation will cause more damage or not.

Due to the proximity of the VIII nerve to the facial (VII) nerve in the cerebello-pontine angle, the VII nerve is particularly vulnerable to the effects of surgical resection. This can result in poor eye closure, lagophthalmos and resultant corneal exposure post VS resection. Additionally, compression from the tumor or resection can cause trigeminal (V) nerve damage and a desensate cornea. The combination of an exposed and desensate cornea puts the eye at risk of serious ocular complications including persistent epithelial defects, corneal ulceration, corneal vascularization, corneal melting and potential perforation. The abducens (VI) nerve can be affected by a large intracranial VS causing raised intracranial pressure (a false localizing sign) or as a result of damage to the VI nerve at the time of resection. Other types of neurogenic strabismus are rare and typically transient. Contralaterally beating nystagmus as a consequence of vestibular dysfunction is common post-operatively. This generally settles to pre-operative levels as central compensation occurs. Ipsilaterally beating nystagmus post- operatively should prompt investigation for post-operative cerebrovascular complications.

Chiu SJ, Hickman SJ, Pepper IM, Tan JHY, Yianni J, Jefferis JM. Neuro-Ophthalmic Complications of Vestibular Schwannoma Resection: Current Perspectives. Eye Brain. 2021 Oct 1;13:241-253. doi: 10.2147/EB.S272326.

https://pmc.ncbi.nlm.nih.gov/articles/PMC8491867/

According to the review, Horner's syndrome is an extremely rare complication that has barely been reported (only one case had been documented, and it was not central Horner).

Thanks for all the suggestions. 

I reviewed the eye movement recording again. She had very subtle left-beating nystagmus on primary gaze (more intense when I checked her pupil in darkness), worse on left gaze and down gaze, with a frequency of 4 Hz . Subtle on upgaze. No nystagmus on right gaze. I'm not sure about the rotational component. Will order a VNG.

She had reported numbness of the left face, which is consistent with V damage. 

This is a comprehensive review of neuro-ophthalmic complications of acoustic neuroma resection. I don't know if ABI implantation will cause more damage or not.

Due to the proximity of the VIII nerve to the facial (VII) nerve in the cerebello-pontine angle, the VII nerve is particularly vulnerable to the effects of surgical resection. This can result in poor eye closure, lagophthalmos and resultant corneal exposure post VS resection. Additionally, compression from the tumor or resection can cause trigeminal (V) nerve damage and a desensate cornea. The combination of an exposed and desensate cornea puts the eye at risk of serious ocular complications including persistent epithelial defects, corneal ulceration, corneal vascularization, corneal melting and potential perforation. The abducens (VI) nerve can be affected by a large intracranial VS causing raised intracranial pressure (a false localizing sign) or as a result of damage to the VI nerve at the time of resection. Other types of neurogenic strabismus are rare and typically transient. Contralaterally beating nystagmus as a consequence of vestibular dysfunction is common post-operatively. This generally settles to pre-operative levels as central compensation occurs. Ipsilaterally beating nystagmus post- operatively should prompt investigation for post-operative cerebrovascular complications.

Chiu SJ, Hickman SJ, Pepper IM, Tan JHY, Yianni J, Jefferis JM. Neuro-Ophthalmic Complications of Vestibular Schwannoma Resection: Current Perspectives. Eye Brain. 2021 Oct 1;13:241-253. doi: 10.2147/EB.S272326.

https://pmc.ncbi.nlm.nih.gov/articles/PMC8491867/

According to the review, Horner's syndrome is an extremely rare complication that has barely been reported (only one case had been documented, and it was not central Horner).