Strabismus Sursumadductorium or IVth Nerve Palsy: Similar Clinical Picture, Different MR Imaging Features
Giovanni B. Marcon, MD; Raffaele Pittino, MD
Strabismological and Diplopia Centre
Bassano del Grappa Italy
Introduction: To evaluate correlations between MRI findings and clinical data in clinically diagnosed IV nerve palsy.|
Methods: Demographic and clinical data were collected. 1.5T orbital MRI was performed with head coil. SO Signal intensity and Cross-sectional area in primary and tertiary gaze were evaluated. Group 1 with SO hypotrophy . Group 2 no SO hypotrophy. Clinical features of the two groups were compared. Multivariate analysis between MRI features and clinical data was performed.
Results: 35 pts were evaluated. Group 1 (16 patients (49 years by mean,10-71), 14 congenital, 2 acquired. Group 2 (19 patients (40 years by mean, 8-75), 10 congenital, 9 acquired. A statistically significant difference between the two groups was observed in primary position deviation but not for motility. In Group 2, rectus pulley displacements were found in 11/19 patients: medial rectus displaced superiorly, superior rectus temporally and inferior rectus pulley displaced nasally. 4 patients (mean age 38, range 11-56 years) exhibited contralateral lateral rectus muscle inferior displacement. 1 patient a supernumerary muscular band . The remaining 3 patients demonstrated normal MRI.
Discussion: Our data confirm that, despite similar clinical features, only 53% of patients diagnosed as IV nerve palsy exhibit mild to severe grade of SO hypotrophy (true IV° nerve palsy); in these patients a more consistent vertical deviation in primary position was found. In 37% of patients MRI demonstrated rectus pulley displacements alone. In 3 cases no significant alterations were found on MRI.
Conclusion: Strabismus in group 2 could be better defined as strabismus sursumadductorium. MRI allows to better identify the diagnosis.
References: Rectus pulley displacements with abnormal oblique contractility explains strabismus in superior oblique palsy
Suh SY, Le A, Clark RA, Demer JL
Ophthalmology. 2016 Jun;123(6):1222-31. doi: 10.1016/j.ophtha.2016.02.016. Epub 2016 Mar 13.