Absence of the fourth cranial nerve in congenital Brown syndrome

Kaeser, Pierre-François; Kress, Bodo; Rohde, Stefan; Kolling, G. H.

doi:10.1111/j.1755-3768.2011.02354.x

Cited by 17 publications

(22 citation statements)

References 18 publications

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“…Recently, it was proposed that congenital BrS could be regarded as a congenital cranial dysinnervation disorder (CCDD). 16,21,22 Ellis et al 22 reported three cases of congenital Brown syndrome without clinical SO palsy, who exhibited moderate to severe ipsilateral SO hypoplasia. They suggested that these congenital cases might represent CCDD due to absence of normal trochlear innervation and without misinnervation.…”

Section: Discussionmentioning

confidence: 99%

“…9 Previous MRI studies focused on localizing pathologic abnormalities in BrS. 6,15,20 While MRI in one prior congenital case showed no change in SO cross-section during vertical gaze shift, 16 no prior study in BrS has analyzed the SO through a large anteroposterior extent of the orbit. The current study showed that the SO muscle had significantly subnormal size bilaterally in congenital cases.…”

Section: Discussionmentioning

confidence: 99%

“…12,13 Previous studies have imaged the SO muscle in BrS, demonstrating occasional hypoplasia in congenital cases. 6,15,16 We therefore reasoned …”

mentioning

confidence: 99%

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Size of the Oblique Extraocular Muscles and Superior Oblique Muscle Contractility in Brown Syndrome

Suh

Demer

2015

Invest. Ophthalmol. Vis. Sci.

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Citation: Suh SY, Le A, Demer JL. Size of the oblique extraocular muscles and superior oblique muscle contractility in Brown syndrome. Invest Ophthalmol Vis Sci. 2015;56:6114-6120. DOI:10.1167/iovs.15-17276 PURPOSE. This study employed magnetic resonance imaging (MRI) to investigate possible size and contractility changes in the superior oblique (SO) muscle, and possible isometric hypertrophy in the inferior oblique (IO) muscle, resulting from abnormal mechanical loading in Brown syndrome (BrS).METHODS. High resolution orbital MRI was obtained in 4 congenital and 11 acquired cases of BrS, and compared with 44 normal subjects. Maximal cross-section areas and posterior partial volumes (PPVs) of the SO were analyzed in central gaze, supraduction, and infraduction for the SO, and in central gaze only for the IO.RESULTS. In congenital BrS, mean maximum SO cross-sectional areas were 24% and 20% less than normal in affected and unaffected eyes, respectively (P ¼ 0.0002). Mean PPV in congenital BrS was also significantly subnormal bilaterally (29% and 34% less in affected and unaffected eyes, respectively, P ¼ 0.001). However, SO muscle size and volume were normal in acquired cases. The SO muscle did not relax in supraduction in BrS, although there was normal contractile thickening in infraduction. The IO muscle had normal size bilaterally in BrS.CONCLUSIONS. Congenital BrS may be associated with SO hypoplasia that could reflect hypoinnervation. However, unique isometric loading of oblique extraocular muscles due to restrictive hypotropia in adduction in BrS is generally not associated with changes in muscle bulk or in SO contractility. Unlike skeletal muscles, the bulk and contractility of extraocular muscles can therefore be regarded as independent of isometric exercise history. Restriction to elevation in BrS typically arises in the trochlea-tendon complex.Keywords: extraocular muscle, magnetic resonance imaging, strabismus T he hallmark of Brown syndrome (BrS) is restrictive limitation to supraduction in adduction. In 1950, Harold Whaley Brown first coined the term ''superior oblique tendon sheath syndrome,'' supposing a short superior oblique (SO) tendon sheath as the cause. 1 In 1975, Parks 2 reported that a restrictive band posterior and inferior to the globe limited elevation in adduction in BrS. In 1982, Helveston 3 suggested fluid accumulation or concretion in the bursa-like space, or vascular distention in the SO tendon sheath, as causes of acquired BrS, impairing SO tendon travel through the trochlea. Subsequent studies have confirmed that pathology generally lies in abnormal SO tendon-trochlea complex, 4,5 although another mechanism involving inferior slip of the lateral rectus pulley has also been identified. 6 The classical mechanism of BrS provides a unique window into extraocular muscle physiology. Impaired SO tendon travel through the trochlea in BrS prevents the SO muscle from elongating during its innervational relaxation in attempted supraduction in adduction. Consequently, the SO experiences unu...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Size of the Oblique Extraocular Muscles and Superior Oblique Muscle Contractility in Brown Syndrome

Suh

Demer

2015

Invest. Ophthalmol. Vis. Sci.

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“…8 An innervational etiology for some cases of congenital Brown syndrome is now also supported since some electromyographic studies revealed paradoxical innervation of superior oblique muscle in some patients with absence of trochlear nerve but non hypoplastic or atrophic superior oblique muscle. 8,9 The size of the muscle remained constant during vertical eye movements, suggesting no relaxation of it in upgaze. This finding can be explained by the existence of anomalous innervation of the superior oblique muscle by fibers of the third cranial nerve intended either for the medial rectus or inferior oblique muscle.…”

Section: Discussionmentioning

confidence: 99%

“…[8][9][10] Otherwise, a dysinnervational Brown syndrome would be expected to persist throughout life.…”

Section: Discussionmentioning

confidence: 99%

Asymmetric Elevation of the Eyes

Nascimento

Pinto

2014

Clin Pediatr (Phila)

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A 26-month-old girl presented with a transient head-posturing to the left that the mother reported since early months. She had a normal growth and psychomotor development, and her parents reported a notion of good vision. The mother denied pain complaints, previous traumatic events, or systemic diseases. Her family history is unremarkable for any history of ophthalmologic problems.On ophthalmologic examination, head-posturing was evident, chin up and a face turn to the left side when asked to look at a symbol of the LEA Vision Chart Test (Figure 1). In the primary position, a minimal right hypotropia was present, and during ocular motricity examination, a limited elevation in adduction of the right eye was present (Figure 2) . An audible but painless superior nasal click was elicited, on ocular rotations up and nasalward. The children had a 10/20 visual acuity of both eyes but had a bad performance during the evaluation of stereoscopic vision, with Lang Test 2. Laboratory exams, which included screening for systemic lupus and juvenile rheumatoid arthritis, were normal. Orbit high-resolution magnetic resonance imaging did not detect any muscular atrophies, signs of inflammation, or orbital tumors. Final DiagnosisCongenital Brown syndrome.

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Thromboembolism and Congenital Malformations

Parsa

Robert²

2013

JAMA Ophthalmol

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To propose a pathophysiologic mechanism to unify a variety of disparate sporadic congenital malformations. Methods: Inductive and deductive analyses to correlate malformation laterality with asymmetries in thoracic anatomy, critical analysis of malformations with female predominance, and concepts of hydrodynamic pressure gradients in vascular growth were applied to the ensuing development of guiding tissue scaffolds for cellular proliferation, differentiation, and apoptosis. Results: Duane syndrome may develop following a focal vascular insult to the sixth nerve trunk with axonal degeneration, allowing for substitutive innervation from third nerve axons to the lateral rectus muscle. Causative fibrin clots may originate from the venous system and paradoxically migrate through physiological right-toleft shunts, or they may arise directly from the heart. Hence, the unilateral, left-sided, and female predominance of Duane syndrome results from the asymmetry in the thoracic anatomy and from thrombosis risk factors. Embolic occlusions may also alter local hemody-namic pressure gradients, leading to the compensatory enlargement and persistence of the fetal vasculature and may dysregulate tissue growth. Within the eye, this results in forms of Peters anomaly, unilateral congenital cataracts, and the morning glory disc anomaly, all in the vascular territory of the carotid arteries that also share a propensity for left-sided involvement in girls. Most aberrant misinnervation phenomena (eg, jaw-winking syndrome, crocodile tear syndrome, Brown syndrome, and congenital fibrosis syndrome) and, by extrapolation, the hypoplasia or dysgenesis of noncephalic anatomical structures (including limbs) may be similarly explained. Such malformations will occur more frequently under thrombogenic conditions, such as those induced by thalidomide. Conclusions: Fibrin emboli and focal hypoperfusion may explain the development of many sporadic congenital malformations.

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Absence of the fourth cranial nerve in congenital Brown syndrome

Cited by 17 publications

References 18 publications

Size of the Oblique Extraocular Muscles and Superior Oblique Muscle Contractility in Brown Syndrome

Size of the Oblique Extraocular Muscles and Superior Oblique Muscle Contractility in Brown Syndrome

Asymmetric Elevation of the Eyes

Thromboembolism and Congenital Malformations

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