Lateral micro-orbitotomy as the technique of choice for orbital pseudotumor in IgG4-RD. Case report and review of the literature.

Immunoglobulin G4-related disease (IgG4-RD) is characterized by a systemic fibroinflammatory infiltrate that often involves the orbit in addition to other tissues. Thus it has to be considered in the differential diagnosis of orbital tumors. We report the clinical case of a 64-year-old woman who presented with right mydriasis, progressive proptosis and paralysis of the third cranial nerve of 1 year of evolution. Cranial MRI identified an intraconal lesion of the right orbit, located between the external and inferior rectus muscles and the optic nerve, and she was scheduled for surgery by transcranial approach with lateral micro-orbitomy. A satisfactory macroscopic excision was achieved with no remarkable complications and a definitive deferred histological result of pseudotumor by IgG4-RD. Follow-up for 24 months showed no tumor recurrence, and the patient clinically improved from ophthalmoplegia. This case highlights the efficacy of lateral orbitotomy in the etiologic diagnosis and successful therapeutic outcome of complex orbital lesions associated with IgG4-RD pseudotumor.

Dynamic Workflow Proposal for Continuous Frameless Electromagnetic Neuronavigation in Rigid Neuroendoscopy.

BACKGROUND: Ventriculoscopic neuronavigation has been described in several articles. However, there are different ventriculoscopes and navigation systems. Due to these different combinations, it is difficult to find detailed neuronavigation protocols. We describe, step-by-step, a simple method to navigate both the trajectory until reaching the ventricular system, as well as the intraventricular work. METHODS: We use a rigid ventriculoscope (LOTTA, KarlStorz) with an electromagnetic stylet (S8-StealthSystem, Medtronic). The protocol is based on a modified or 3-dimensionally printed trocar for navigating the extraventricular step and on a modified pediatric nasogastric tube for the intraventricular navigation. RESULTS: This protocol can be set up in less than 10 minutes. The extraventricular part is navigated by introducing the electromagnetic stylet inside the modified or 3-dimensionally printed trocar. Intraventricular navigation is done by combining a modified pediatric nasogastric tube with the electromagnetic stylet inside the endoscope's working channel. The most critical point is to obtain a blunt-bloodless ventriculostomy while achieving perfect alignment of all targeted structures via pure straight trajectories. CONCLUSIONS: This protocol is easy-to-set-up, avoids head rigid-fixation and bulky optical-based attachments to the ventriculoscope, and allows continuous navigation of both parts of the surgery. Since we have implemented this protocol, we have noticed a significant enhancement in both simple and complex ventriculoscopic procedures because the surgery is dramatically simplified.