Das Kopfneigephänomen bei einseitigen und beidseitig symmetrischen Trochlearisparesen

Abstract

The head-tilt phenomenon is smaller in long-standing bilateral symmetric superior oblique palsies than in long-standing unilateral superior oblique palsy. This finding supports the hypothesis that in unilateral superior oblique palsy, an adaptive mechanism augments the head-tilt phenomenon by an amplification of the otolith reflex. However, we presume that the amplification of the otolith reflex is only a side effect of the adaptive change of the vertical fusional vergence tonus and thus the price of the improved vertical fusion, rather than a compensatory mechanism.

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

“…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).…”

“…Such a large hyperdeviation, which is more typical of congenital superior oblique palsy, cannot solely result from the lack of the depressing force of the superior oblique muscle. It can be interpreted as a side-effect of adaptation [11,[26][27][28]33]. Excyclodeviation of more than 12°usually indicates bilateral palsy [21][22][23][24][25].…”

Effect of diagnostic occlusion in acquired trochlear nerve palsy

“…V-incomitance is said to be typical of trochlear nerve palsy. Indeed, bilateral trochlear nerve palsy regularly causes significant V-incomitance [8]. In our patients, Vincomitance exceeding 5°occurred in not more than six cases before and after occlusion.…”

“…Huge vertical deviation and a great head-tilt phenomenon can be explained as an epiphenomenon of adaptation [8,23]. Central gain-modulation, as a side-effect of the compensatory fusional vergence tonus, leads to pathological innervation of vertical rectus muscles [8]. Congenital superior oblique palsy is an example of maximum adaptation with minimization of cyclodeviation.…”

“…In many cases, the overall increase in vertical deviation and the amount of the head-tilt phenomenon cannot be caused by the reduced depressing effect of the paretic superior oblique muscle alone. Huge vertical deviation and a great head-tilt phenomenon can be explained as an epiphenomenon of adaptation [8,23]. Central gain-modulation, as a side-effect of the compensatory fusional vergence tonus, leads to pathological innervation of vertical rectus muscles [8].…”