Isolated superior oblique palsy as a complication of pansinusitis following root canal treatment – An unusual scenario

Abstract

Isolated superior oblique (SO) palsy has been reported in cavernous sinus thrombosis, pituitary microadenoma, tuberculous meningitis, following intraoral local anesthesia, and inferior alveolar nerve block. A 14-year-old boy presented with right SO palsy. There was a history of facial cellulitis, following dental root canal treatment (RCT) 2 weeks back. Magnetic resonance imaging revealed right pansinusitis and breach of the lamina papyracea, with extension of inflammation into the orbit. Complete recovery was noted 1 week after functional endoscopic sinus surgery. The association of SO palsy with sinusitis can be explained by the anatomical proximity of the trochlear nerve to the paranasal sinus or by the extension of infection into the superior orbital fissure. Trochlear nerve is particularly vulnerable due to its location outside the annulus of Zinn. Although multiple ocular nerve palsy following sinusitis is well recognized, isolated SO palsy in pansinusitis following dental RCT has not been reported. An inflammatory etiology carries a favorable prognosis.