[Click phenomenon in acquired Jaensch-Brown syndrome and trigger finger/thumb: the Notta syndrome]. / "Klick"-Phänomen beim erworbenen Jaensch-Brown-Syndrom und schnellenden Finger/Daumen: dem Notta-Syndrom.

CLINICAL FEATURES: The click phenomenon occurs when an acquired mechanical restriction of the elevation in adduction of the eye or of the extension of the finger/thumb, is forcefully overcome. The common cause is a nodule either of the superior oblique tendon posterior to the trochlea in the case of a Jaensch-Brown syndrome or of the digital flexor tendon anterior to the A1 annular pulley in the case of a trigger finger. Both locations share similar anatomical conditions for the development of the nodule and the pathomechanism of the click. RESULTS: From these identical findings in the eye and the hand in small children it can be assumed that the results from the studies of the hand in newborns and infants with a trigger thumb/finger are also applicable to the situation of the eye. 1. This motility disorder is not congenital. This is most likely due to an incomplete development at the time of birth of the sliding factors needed for a free passage of the tendon through the trochlea and the A1 annular pulley. 2. A distinction must be made between stages 0-3: stage 0 = no more restriction of the motility and no click phenomenon; stage 1 = forced active extension/elevation possible; stage 2 = only passive extension/elevation, each with a click phenomenon; stage 3 = no extension/elevation possible and no click phenomenon. 3. In most cases in early childhood there is a spontaneous complete recovery (75% after 6-7 years). In the eye this spontaneous course can only limitedly be shortened with motility exercises in combination with segmental occlusion. CONCLUSION: The click phenomenon is a symptom of stages 1 and 2 of an acquired mechanical restriction of the elevation in adduction of the eye or the extension of the finger/thumb. It should not be called a syndrome.

[Superior oblique tendon trochlear passage syndrome : Causes, motility findings and treatment of acquired Jaensch-Brown syndrome]. / Obliquus-superior-Sehne-Trochlea-Passage-Syndrom : Ursachen, Motilitätsbefund, Therapie beim erworbenen Jaensch-Brown-Syndrom.

CLINICAL FEATURES: Acquired Jaensch-Brown syndrome is characterized by a mechanical limitation of elevation in adduction, with orthophoria in downward gaze. It was first described by Jaensch in 1928 after orbital trauma in his case and has the same motility pattern as congenital Brown's syndrome. For this reason, in 1973 Brown differentiated between the "true" and "simulated" cases. Further clinical findings of the different etiological factors must be considered in order to differentiate between the two groups. ORIGIN: The cause is an acquired restriction of the free passage of the superior oblique tendon through the trochlea. In most cases this is produced by a palpable swelling/nodule of the superior oblique tendon posterior to the trochlea. There are three possibilities to develop a swelling/nodule: 1. Shortly after birth due to an incomplete development at the time of birth of the sliding factors needed for a free passage. 2. An inflammation in combination with a systemic disease, such as rheumatism or idiopathic. 3. A blunt orbital trauma causing a hematoma of the superior oblique tendon. Additionally, the trochlear passage can be narrowed by a severe inflammation involving the trochlea, which is associated with a swelling and marked tenderness of the trochlear area and corresponds to stenosing tenosynovitis of the hand. TREATMENT: The therapeutic management of these four variations differs significantly depending on the cause of the swelling. CONCLUSION: The swelling of the superior oblique tendon posterior to the trochlea explains the motility disorder in acquired Jaensch-Brown syndrome. There are three different causes for the swelling, which require different therapeutic management.

[Brown's atavistic superior oblique syndrome: etiology of different types of motility disorders in congenital Brown's syndrome]. / Atavistischer Obliquus-superior-Brown-Syndrom: Ätiologie der verschiedenen Arten von Motilitätsstörungen beim kongenitalen Brown-Syndrom.

CLINICAL FEATURES: The congenital Brown syndrome is characterized by a mechanical limitation of elevation in adduction, with an orthophoria in down gaze. Brown postulated a shortened superior oblique tendon sheath as the cause of the limitation but this was disproved by Parks et al. in 1975 and the origin of Brown syndrome remains unclear. In recent years, a congenital dysinnervation has been discussed; however, this does not explain the full spectrum of abnormalities and especially contradicts the unlimited depression in adduction seen in Brown syndrome. ORIGIN: Surgical exploration in Brown true typical cases reveals a fibrotic strand, typically located at the posterior margin of the superior oblique tendon. This strand originates from the trochlear area and has a common insertion with the superior oblique tendon posterior to the equator into the globe. It may represent an atavistic superior oblique muscle as described by Fink in various animals. They do not have a trochlea but a superior oblique muscle originating in the anterior superior nasal orbit. ATYPICAL BROWN SYNDROME: A fibrotic strand was also surgically revealed in two cases of atypical Brown syndrome. In the first case an elevation deficit-as in Brown true atypical cases-also present in abduction could be explained by an unusual insertion of the fibrotic strand anterior to the equator. The second case showed a fibrotic strand which was completely separated from the superior oblique tendon and inserted far posterior to the equator nasal to the superior rectus muscle. This finding had not been previously described and explained the total elevation restriction which was suddenly in > 30° adduction and the Y­pattern exotropia which increased in adduction and decreased in abduction. TREATMENT AND FOLLOW-UP: A 10 mm excision of the fibrotic strand from the insertion gives the best results from all procedures. The residual limitation of active elevation in adduction improved with gaze exercises mostly after more than 1 year. CONCLUSION: The fibrotic strand, an atavistic superior oblique muscle, not only explains the typical Brown syndrome but also-by its variable insertion-different patterns of elevation deficits seen in atypical Brown syndrome. A 10 mm excision of the strand gives good functional results of abnormal head position (immediate in most cases) and even elevation in adduction (after 1 year in most cases).