Tuesday, February 19, 2013

2/15/13 Case Summary

We discussed Cases 1 and 2 during a webinar last Friday. The presentation is saved at:
Some of the audio is involved with the formatting and use of smartphones and tablets to answer the questions.

Summary of Case 1:

The patient has a sensory extropia secondary to traumatic optic neuropathy and correction can involve right lateral rectus recession and right medial rectus resection. Patients with one poor-seeing eye usually prefer to have surgery on that eye, and usually that is feasible.

There are some cases where the plan with the higher likelihood of success involves operating on the better seeing eye. In those cases, I try to explain to patient (or parent) how their goals are more likely to be achieved with surgery on the sound eye, and what to expect if surgery is only performed on the unsound eye. If they decide to only operate on the poor eye, then I operate on that eye only.

Summary of Case 2:

An intermittent hypertropia implies an early onset, which can be important when evaluating a patient with a "new" vertical deviation- if they are fusing a hypertropia >5PD, it's probably not an acute process.

The management of 4th nerve palsy with or without inferior oblique overaction has a number of options, determined by assessment of versions, torsion, head osition, and patient age. A general rule of strabismus surgery planning is to operate on the muscles with a field of action on the direction where the deviation is greatest. In this case, the left hypertropia is worse in right gaze, so the options are to work on the vertical recti of the right eye, or the obliques of the left eye.

Left inferior oblique myotomy/recession would correct the inferior oblique overaction and up to 12-15PD of hypertropia. It will have a modest incyclorsion. I've found a myotomy works well in children, but may leave residual deviations in adults. Myotomy is not adjustable; recession can be adjusted.

Left superior oblique tuck will improve the ability to depress in adduction, so can be considered in cases with moderate to severe superior oblique underaction. It will result in a large incyclorotation and may cause a Brown syndrome if the tuck is too tight. A tuck is not easily adjusted.

Left superior oblique Harada-Ito can cause a moderate to large incyclotorsion with minimal effect on vertical alignment. The procedure can be used as a solitary procedure for isolated torsion, or combined with other vertical muscle surgery. The Harada-Ito can be adjusted.

Right inferior rectus recession works well in adults and is easily adjusted. It can result in a moderate incyclotorsion, especially if it is displaced nasally. Inferior rectus recession should be avoided if there is minimal (or no) hypertropia in downgaze, as it may cause the hypertropia to "flip" in downgaze with difficulty reading post-operatively.

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