Vertical Gaze Restriction and Ptosis after Neurosurgical Removal of the Orbital Roof

Abstract

 

Purpose

 

To describe post-operative vertical diplopia and ptosis in a series of patients who have undergone neurosurgery via the pterional approach, involving removal of the orbital roof.

 

Methods

 

Review of patient records of a single neuro-ophthalmologist from 1998 to 2013 identified 7 patients with persistent post-op vertical diplopia. In all cases the orbital roof was resected to gain better access to the anterior cranial fossa. No patient had diplopia from a cranial nerve palsy. The op report, CT or MRI imaging, intracranial pathology, neurovisual exam, ocular deviation, and degree of ptosis were recorded. Subsequent treatment and patient outcome were documented.

 

Results

 

Three patients underwent a pterional craniotomy for clipping of an anterior communicating artery aneurysm and 1 patient had a supraclinoid carotid artery aneurysm. The remaining 3 patients had resection of a sphenoid wing meningioma. After surgery, all 7 patients had an elevation deficit on the affected side. Two patients also had a depression deficit. Six out of 7 patients had ptosis. In primary gaze, 5/7 patients had a hypotropia and all patients had a hypotropia on upgaze. Neuroimaging revealed a bony defect in the orbital roof in all cases. The superior rectus/levator complex had an abnormal appearance, with loss of the fat layer which separates it from the orbital roof. Two patients were prescribed prism glasses, 1 patient underwent strabismus surgery, 1 patient underwent ptosis repair, and 3 patients declined intervention.

 

Conclusions

 

Vertical diplopia and ptosis are rare and under-recognized complications of neurosurgical removal of the orbital roof. The gaze limitation observed clinically, which can involve depression and elevation, implies that the superior rectus/levator complex becomes adherent to the dura underneath the frontal lobe in the absence of a normal orbital roof. Tethering of the muscles appears to produce restriction of vertical gaze, in a manner analogous to orbital floor fractures. When necessary, recession of the inferior rectus muscle using an adjustable suture technique, prism glasses, and ptosis repair surgery can be undertaken to alleviate symptoms.

 

 

Post-op images from a patient showing a defect in the right orbital roof with adhesion of the superior rectus/levator complex producing vertical diplopia and ptosis. (A) MRI T1 pre-contrast coronal (B) post-contrast coronal (C) CT coronal (D) CT left oblique.

 

Keywords: 631 orbit • 724 strabismus: etiology • 725 strabismus: treatment