Effect of diagnostic occlusion in acquired trochlear nerve palsy

Gräf, Michael; Weihs, Johannes

doi:10.1007/s00417-008-0950-0

Cited by 6 publications

(8 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…45 Widespread changes in innervation to multiple EOMs may explain the absence of relationship between oblique EOM size and magnitude of the head tilt phenomenon in human SO palsy, 46 and the effect of prolonged diagnostic occlusion, which in many humans with longstanding SO palsy causes an increase in excyclotropia without a consistent change in hypertropia. 47 Dissociation between the mechanically expected effects of IO action in the setting of SO palsy implies the existence of selectively controllable cyclovertical actions of the rectus EOMs. A mechanism for neural control of cyclovertical action of the LR has recently been suggested based on its compartmentalization into superior and inferior zones.…”

Section: Discussionmentioning

confidence: 98%

Effects of Intracranial Trochlear Neurectomy on the Structure of the Primate Superior Oblique Muscle

Demer

Poukens²,

Ying³

et al. 2010

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

PURPOSE. Although cyclovertical strabismus in humans is frequently attributed to superior oblique (SO) palsy, anatomic effects of SO denervation have not been studied. Magnetic resonance imaging (MRI) and orbital histology was used to study the effects of acute trochlear (CN4) denervation on the monkey SO. METHODS. Five juvenile macaque monkeys were perfused with formalin for 5 weeks: 15 months after unilateral or bilateral 10-mm intracranial trochlear neurectomy. Denervated and fellow orbits were imaged by MRI, embedded whole in paraffin, serially sectioned at 10-mum thickness, and stained with Masson trichrome. Whole muscle and individual fiber cross sections were quantified in SO muscles throughout the orbit and traced larger fibers in one specimen where they were present. RESULTS. MRI demonstrated marked reduction in midorbital cross section in denervated SO muscles, with anterior shift of SO mass preserving overall volume. Muscle fibers exhibited variable atrophy along their lengths. Denervated orbital layer (OL) fiber cross sections were slightly but significantly reduced from control at most anteroposterior locations, but this reduction was much more profound in global layer (GL) fibers. Intraorbital and intramuscular CN4 were uniformly fibrotic. In one animal, there were scattered clusters of markedly hypertrophic GL fibers that exhibited only sparse myomyous junctions only anteriorly. CONCLUSIONS. CN4 denervation produces predominantly SO GL atrophy with relative OL sparing. Overall midorbital SO atrophy was evident by MRI as early as 5 weeks after denervation, as denervated SO volume shifted anteriorly. Occasional GL fiber hypertrophy suggests that at least some SO fibers extend essentially the full muscle length after trochlear neurectomy.

show abstract

Section: Discussionmentioning

confidence: 98%

Effects of Intracranial Trochlear Neurectomy on the Structure of the Primate Superior Oblique Muscle

Demer

Poukens²,

Ying³

et al. 2010

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

show abstract

“…For 37 patients, the 3-month follow-up data were available. The median dose of pure SOT was 8 mm (6-8), the median dose of SOT when combined with IOR was 6 mm (4-8), the median total amount of SOT&IOR was 11 mm (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18).…”

Section: Resultsmentioning

confidence: 99%

“…The squint angles were taken for evaluation as localized by the patient on the screen (without previous diagnostic occlusion [13]). Using this method, the patient can only see the bright central fixation light and the light bar of the tangent screen through the dark red glass in front of the non-paretic eye.…”

Section: Methodsmentioning

confidence: 99%

Superior oblique tucking with versus without additional inferior oblique recession for acquired trochlear nerve palsy

Gräf

Lorenz

Eckstein³

et al. 2009

Graefes Arch Clin Exp Ophthalmol

Self Cite

View full text Add to dashboard Cite

show abstract

“…Increasing image separation could be a strategy to reduce visual confusion 19 . It is also possible that with both eyes viewing a compensatory fusional incyclovergence reduces the excyclodeviation but at the expense of an increase in the VD 20 . But these mechanisms do not account for the increased vertical deviation that occurred under monocular viewing.…”

Section: Discussionmentioning

confidence: 99%

Vertical alignment in monkeys with unilateral IV section: effects of prolonged monocular patching and trigeminal deafferentation

Shan¹,

Hamasaki²,

Tian³

et al. 2011

Annals of the New York Academy of Sciences

View full text Add to dashboard Cite

We investigated monocular viewing and trigeminal (V) deafferentation on the vertical deviation (VD) in monkeys following intracranial IV section. Two monkeys wore a patch for four to six weeks, one over the paretic eye and the other over the normal eye following IV section. Two other monkeys had combined IV and V section with the paretic eye patched postlesion. In monkeys with IV section alone, the VD lessened within the first week postlesion but then increased gradually with the same eye still patched. Thus binocular viewing was unnecessary for the later VD increase. With combined IV and V section, the VD also transiently lessened postlesion. We have proposed that the decrease in VD after IV section is adaptive, driven by an error signal using ocular proprioception and efference copy. Since V section did not eliminate the early decrease in VD, we suggest some orbital afference is transmitted centrally via other cranial nerves. However, the later increase in VD suggests either that the proprioceptive effect cannot be sustained or that mechanical changes supervene to increase the VD.

show abstract

Effect of diagnostic occlusion in acquired trochlear nerve palsy

Cited by 6 publications

References 28 publications

Effects of Intracranial Trochlear Neurectomy on the Structure of the Primate Superior Oblique Muscle

Effects of Intracranial Trochlear Neurectomy on the Structure of the Primate Superior Oblique Muscle

Superior oblique tucking with versus without additional inferior oblique recession for acquired trochlear nerve palsy

Vertical alignment in monkeys with unilateral IV section: effects of prolonged monocular patching and trigeminal deafferentation

Contact Info

Product

Resources

About