Case of the week 101.html

Dear dr Gamal your case is verry interesting for management of this case we have to go into steps the first step is good history taking as regard the onset of the anomaly and if not congenital we have to rule out history of trauma thyroid hyperfunction any previous cerebrovascular insult and of course any previous EOMs surgery.
Anyway I will consider this case as a monocular elevation defeciency of the right eye.During examination I should test for Bell s phenomenon in the right eye because sometimes it is present despite the great innability to raise the eye and if it is present this mean that we are dealing with a true double elevator palsy of a supranuclear origin and ofcourse this rule out IR muscle contraction .If there is no Bell s then FDT is mandatory to differentiate between true double elevator palsy of nuclear origin or IR muscle contracture.
Neuroimaging is needed only if the case is not congenital.
If the FDT is positive our surgery is directed toward releaving the restrction of the I R muscle by doing recession and after the FDT test become negative the ipsilateral SR muscle may be plicated as well.
If the FDT is negative most authority proceed with Knapp procedure ie vertical transposition of the horizontal recti to the insertion of the SR muscle.
My view is to weaken the Yoke muscles ie I do a contralateral anchored hang back recession of the SR muscle combined with faden suture and to weaken the contralateral IO muscle this will correct the hypotropia in the PP position and increase the innervational flow to the paralyzed muscle if still hypotropia is not totaly corrected then we can add surgery on the vertical recti of the affected eye.
I prefer my view because in Knapp procedure you may correct hypotropia in PP but you didn't eliminates overaction of the Yoke muscles which may result in incommitance in other directions of gaze postoperatively and there is no improvement of innervational flow in the affected muscles .Besides with Knapp procedure elevation may improve after a long time

Prof. Dr. Ibrahim Taha El Adawy :

Thank you Dr Gamal for this interesting case ,and many thanks to my dear brother prof. Dr.

Mahmoud for very nice analysis of the case. I completely agree with Dr.Mahmoud in his

analysis especially whether the case is congenital or aquired , presence or absence of Bell's

phenomenon, but i would like to ask about vision in this eye and wether the patient can

fixate with this eye or not . because if he has poor vision in this eye; this means that the

patient uses his sound eye in fixation and so, secondry changes will occur mainly in the

paretic eye and so in this situation Knapp;s procedure will give a very good result . but if he

has good vision in this eye and can fixate with this paretic eye; this means that he

sometimes uses the secondry deviation and so secondry changes will occur mainly in the

sound eye i.e. S.R. overaction and in this situation, S.R. recession of the sound eye is

mandatory. sometimes in very large angle of deviation I combine Knapp's in the paretic eye

and S.R. recession of the sound eye but in separete session. actually as Dr. Mahmoud said,

the effect of knapp's is delayed ,it takes about 3 to 4 months, but it's result is very good.

finally thank you Dr. gamal for giving me the chance for this very nice discussion, thank you

Dr. mahmoud for this systematic analysis thanks to all colleages

Prof. Dr. Mahmoud Rageh :
I respect very much the point of view of professor dr Ibrahim but my question is? We know

that when there is paresis or paralysis of one muscle there are 2 muscles overacting that is

the direct antagonist and the yoke but the difference between the 2overactions is that it

due to contracture of the direct antagonist i e irreversible and due to hypertrophy of the

yoke i e reversible. So provided secondary changes occurs in the diseased eye in case the

vision is very poor in this eye and the sound eye is the fixing eye this means that the

secondary changes are contracture of the IR and SO muscles which are irriversable and

doing Knapp procedure alone result in pulling the eye up against a lower resistance So the

IR muscle should be recessed as well with a risk of anterior segment ischaemia not only

that when this eye adducts there is incomitance due to contracture of the SO muscle and

the eye may go down.Besides even if the affected eye has poor vision the sound eye is the

leading eye and weakening of the yokes results when the sound eye looks up the SR and IO

need more innervational impulse that reaches as well the SR and IO muscle (Herring s Law)

that may improve their actions and elevation is improved in the affected eye.I know that

scientific discutions are endless with a great professor like dr Ibrahim simply because his

experience and knowledge in strabismus are endless as well but all the benefits of the

discussions goes to us and all the dear colleagues and in fact this is due to the superb

efforts professor Gamal is doing