[Jaensch-Brown syndrome--etiology and surgical procedure]

The classical clinical picture of inferior oblique pseudopalsy can be caused by (1) a tight connection between the superior oblique insertion and the trochlea and (2) a thickening of the tendon restricting the passage of the tendon through the trochlea. The entity may be congenital or acquired and constant or intermittend. A spontaneous cure is possible.

We looked for the cause of the inferior oblique pseudopalsy in 41 patients operated on during the last 15 years. 31 patients had a congenital and 10 an acquired inferior oblique pseudopalsy. None of these cases had an alteration of the sheath of the superior oblique tendon. Instead we found a tight band at the posterior border of the tendon between the trochlea and the sclera in all patients with a congenital inferior oblique pseudopalsy. Resection of this band, either in toto or soley of the portion near the sclera resulted in a normalisation of the active and passive elevation in adduction. In some patients a second operation was necessary. The 'V-pattern' existing preoperatively regressed in part or completely during the 1.5 postoperatives years. A consecutive superior oblique palsy was seen in one case only.

A tight band at the posterior border of the tendon between the trochlea and the sclera explains the congenital variety of the inferior oblique pseudopalsy in many cases. A thickening of the tendon restricting the passage of the tendon through the trochlea may play a role in some cases, particularly in those with a spontaneous cure, but the surgical approach used in this series of patients was not suited to verify this mechanism.

The pathognomonic signs of the inferior oblique pseudopalsy, restriction of active and passive elevation in adduction, were first described by Jaensch in 1928 in an acquired case, and Jaensch already suggested a tight band between the trochlea and the sclera as the mechanism. Brown, in 1950, only added the congenital variety. Since we owe the first description of the inferior oblique pseudopalsy to Jaensch, his name should be included in the designation of the syndrome, i.e., it should be called "Jaensch-Brown syndrome" rather than "Brown's syndrome". The name suggested by Brown, "superior oblique tendon sheath syndrome", is no longer appropriate since the tissue surrounding the superior oblique tendon is normal.