Double Elevator Palsy

Paralysis of both elevator muscles (superior rectus and inferior oblique muscles) is an unusual anomaly of ocular motility. When the patient fixates with the nonparetic eye, the paretic eye will take a hypotropic position and the upper lid may be ptotic. Fixation with the paretic eye will cause a hypertropia of the nonparetic eye, and ptosis may disappear, provided the levator palpebrae is not involved. Elevation of the paretic eye from any position of gaze is severely restricted, hence the term double elevator palsy. Bell’s phenomenon is usually preserved but may also be absent. The ductions of the paretic eye are normal in all other positions of gaze. The chin is usually elevated. This anomaly is often congenital. It was postulated that monocular elevation paresis could be attributed to a unilateral lesion in the pretectum, probably as a result of occlusion of one of the fine blood vessels supplying this area. The differential diagnosis of a double elevator paralysis includes inability to elevate the eye because of mechanical restriction involving the inferior aspect of the globe caused by a blow-out fracture of the orbital floor, congenital or acquired fibrosis, endocrine myopathy, anomalous insertion of the inferior rectus muscle, or an abnormal accessory muscle between the annulus of Zinn and the posterior part of the globe. A positive forced duction test and increased intraocular pressure in upward gaze may distinguish these conditions from double elevator palsy although it must also be considered that this muscle may become tight as a result of the elevation deficiency.

Not every case requires surgery, which is indicated only when there is hypotropia of the involved eye in primary position or chin elevation or both. The aim of surgery is to restore single binocular vision in primary position. Knapp introduced vertical transposition of the horizontal rectus muscles to the medial and lateral edge of the superior rectus muscle insertion (Knapp procedure) for the treatment of this condition. This operation has been successful provided there is no contracture of the inferior rectus muscle. If contracture is present a recession of that muscle becomes also necessary. In cases where it is difficult to determine whether the hypotropia is maintained by a primary inferior rectus tightness alone or by an innervational deficit of the elevator muscle(s) it is best to perform the operation in two stages, beginning with recessing the inferior rectus muscle, after which the situation should be reassessed. A complication of surgery is limitation of depression of the eye operated on, with diplopia in downward gaze. In such instances we have performed a recession of the contralateral inferior rectus muscle on an adjustable suture and eliminated the problem.