Presentation on theme: "Special Forms of Strabismus"— Presentation transcript:
1Special Forms of Strabismus Abbas Attarzadeh MDProfessor of ophthalmologySUMS
2Duane SyndromeRetraction of the globe in actual or attempted adduction.Horizontal eye movement is usually somewhat limited in both directions.Upshoot or downshoot (leash phenomenon)of the affected eye in attempted adductionco-contraction of the medial and lateral rectus musclesand, alternatively, to slipping of the lateral rectus muscle over the outer aspect of the eye.
4Most cases of Duane syndrome are sporadic 5%-10% show autosomal dominant inheritanceA higher prevalence in females
5In most anatomical and imaging studies, the nucleus of the sixth cranial nerve is absent, and an aberrant branch of the third cranial nerve has innervated the lateral rectus muscle
6Electromyographic studies have shown: paradoxical innervation of the lateral rectus muscle (innervation on attempted adduction and reduced innervation on attempted abduction).Anomalous synergistic innervation of the medial, inferior, and superior rectus muscles and the oblique muscles
7Although considered an innervational anomaly: Tight and broadly inserted medial rectus muscles Fibrotic lateral rectus muscles, with corresponding forced duction abnormalities, are often encountered at surgery.
8Clinical FeaturesPoor abduction, frequently with primary position esotropiaPoor adduction and exotropiaPoor abduction and adduction, with esotropia, exotropia, or no primary position deviation50%-80% in several seriesAbout 15% of cases are bilateral;
9DDX with sixth nerve palsy Careful observation for globe retraction on adductionlack of correspondence between the absent or typically modest primary position esotropia and the usually profound abduction deficitA further point of differentiation is that, even in esotropic Duane syndrome, a small-angle exotropia frequently is present in gaze to the side opposite the affected eye
10Management Indications for surgery Primary position deviationsAbnormal head positionMarked globe retractionLarge upshoots or downshoots
11Duane syndrome with esotropia Recession of the medial rectus muscle on the involved sideBimedial rectus recession recommended for deviations over 20∆ in primary positionResection of the lateral rectus muscle for Duane syndrome with esotropia is not favoredbecause of the likelihood that globe retraction will worsen,although one studyreported favorable results with unilateral recession-resection procedures
13Partial or full transposition of the vertical rectus muscles has been advocated to improve abduction but may exaggerate the effects of co-contraction.Posterior scleral fixation of the transposedportions of the vertical rectus muscles, as described by Foster, has been found helpful,no only in Duane syndrome but in several types of paralytic strabismus as well
15The value of botulinum injection into the medial rectus muscle to improve abduction is controversial
16Duane syndrome with exotropia and deficient adduction (type 2) Recession of the lateral rectus on the involved side for small deviationsBoth lateral recti for large deviationswith avoidance of resection of the medial rectusThe latter aspect is especiallyimportant when an up- or downshoot is present on attempted adduction, because thisfinding indicates severe co-contraction
17type 3 Duane syndrome who have poor abduction and adduction Have straight eyes in or near the primary position and little, if any, head turnSevere globe retraction may be helped by:Recession of both the medial and the lateral rectus musclesSplitting the lateral rectus muscle in a Y configurationA posterior fixation procedure on LRDisinsertion of the lateral rectus muscle and reattachment to the lateral wall of the orbit is the most recent procedure to be tried
20Shortening of the anterior sheath of the superior oblique tendon. Brown syndrome was described by Harold W. Brown in 1950 as the superior oblique tendonsheath syndrome.restriction of elevation in adductionShortening of the anterior sheath of the superior oblique tendon.Restriction of the superior oblique tendon at the trochlear pulleyabandoned this theory
21Brown SyndromeRestriction of the superior oblique tendon at the trochlear pulley
22Brown syndrome Congenital Acquired form bilateral in approximately 10% of casesCongenitalAcquired formTrauma in the region of the trochleaSystemic inflammatoryResolution of congenital Brown syndrome is unusual but possibleintermittent Brown syndrome, which may resolvespontaneously.
23Comparison of Inferior Oblique Muscle Palsy With Brown Syndrome Deficient elevation in adduction that improves in abduction but often not completelyInferior Oblique Muscle PalsyBrown SyndromeForced ductionsNegativePositiveStrabismus patternA patternV patternSuperior oblique muscle overactionUsually presentNone or minimalIn adduction, the palpebral fissure widens and a downshoot of the involved eye is often seen; it can be distinguished from superior oblique muscle overaction because downshoot in the latter condition occurs less abruptly as adduction is increased.
24Brown syndrome OS Divergence in upgaze Down shoot in attempted elevation in adduction?Down shoot in attempted elev. in adduct. (different than IO palsy)
25Brown syndrome mild moderate severe hypotropia in primary position no yesdownshoot of the eye in adduction.chin-up head posture and sometimes by a face turnawayfrom the affected eye insever cases
26in adduction is essential for the diagnosis of Brown syndrome. An unequivocally positive forced duction test demonstrating restricted passive elevationin adduction is essential for the diagnosis of Brown syndrome.Retropulsion of the globeduring this determination stretches the superior oblique tendon and accentuatesthe restriction.When inferior rectus muscle fibrosis or inferior orbital blowout fracture(the principal entities to be differentiated) produces a restrictive elevation deficiency,the limitation to passive elevation is accentuated by forceps-induced proptosis of the eye rather than by retropulsion.
27ManagementObservation alone in about two thirds of all Brown syndrome casesrheumatoid arthritis or other systemic inflammatory diseasesSystemic treatmentCorticosteroids injected near the trochleaSinusitis has also led to Brown syndromeCT of the orbits and paranasal sinuses
28Surgical treatment is indicated for the most severe cases Primary position hypotropiaAnomalous head postureIatrogenic superior oblique muscle palsy may occur postoperatively. 44%-82%sheathectomyhas been abandoned in favor of ipsilateral superior oblique tenotomy
30Superior oblique muscle palsy Reduced: By careful preservation of the intermuscular septum during tenotomy. This modification often produces an early under correction that gradually improves with time
31Perform simultaneous ipsilateral inferior oblique muscle weakening. guarded tenotomy using an inert spacer sewn to the cut ends of the superior oblique tendonControlling the gap between the cut ends with an adjustable sutureThese procedures eliminate the need for simultaneous inferior oblique muscleweakening but sometimes result in a downgaze restriction due to adhesions to the nasalborder of the superior rectus muscle. Care must be taken to avoid contact of the spacer tonearby structures by preserving the intermuscular septum
32For those surgeons who are a little too chicken to completely cut the SO tendon and cause a SO palsy… Chicken suture technique
39The causes of third cranial nerve palsy in children Congenital disorders (40%-50%)TraumaInflammationViral infectionMigraine(Infrequently) neoplastic lesionsAdultsIntracranial aneurysmDiabetes,NeuritisInfectionRarely, tumorDiabetic third cranial nerve palsy generally resolves spontaneously within 3-4 months.The majority of adults referred for surgical treatment have palsy due to trauma
40Clinical Features Limited: Adduction Elevation Depression Exotropia and often HypotropiaUpper lid ptosis usually is present, often with a pseudoptosis
42Niknam Farshad 23 yo accident 4years ago 3rd nerve palsy aberrant regeneration
43ManagementExcept in congenital cases of third cranial nerve palsy, it is advisable to wait 6-12 monthsfor any spontaneous recovery before surgical correction is planned.Patients with at leastpartial recovery are much better candidates for good functional, as well as cosmetic, results,
45Third cranial nerve palsies present difficult surgical challenges because multiple extraocular muscles as well as the levator may be involved.Replacing all of the lost rotational forces on the globe is impossible; therefore, the goals of surgery must be thoroughly discussedWith patients so their expectations are realistic, Adequate alignment for binocular function in primary position and in slight downgaze for reading may be all that can be expected.
46Sadravy Bahareh post surgery rt 3rd N palsy 15 years po 9.3.86
47surgical procedureA large recession-resection procedure on the horizontal rectus muscles to correct the exodeviation, with supraplacement of both to correct the hypotropiaMost surgeons reserve correction of ptosis for a subsequent procedureSome surgeons use superior oblique tenotomy instead of supraplacement of the horizontal rectus muscles for hypotropia
50Edema, inflammation, and fibrosis are present in this disease because of lymphocytic infiltration. These conditions result in massive enlargement of affected extraocularmuscles and may not only restrict motility but also cause compressive optic neuropathy.
52Detection of this muscle enlargement by orbital ultrasound, CT, or MRI helps confirm the diagnosis of Graves eye disease.
53The myopathy is not caused by thyroid dysfunction Some patients with Graves disease also have myasthenia gravisIt is mostly a disease of adults but can occur in children.
54Clinical FeaturesSevere restrictive, The muscles affected, in decreasing order of severity and frequency:inferior rectusmedial rectusSuperior rectuslateral rectusThe condition most often is bilateral and asymmetric.Forced duction test results are almost always positive in 1 or more directions.
55Upper eyelid retraction often is present. The patient presents most often with some degree of proptosis, hypotropia, or esotropiaUpper eyelid retraction often is present.Graves eye disease is a common cause of acquired vertical deviation in adults, especially females, but is rare in children
56Management Indications for strabismus surgery: Diplopia Abnormal head positionSurgery may eliminate diplopia in primary gaze but rarely restores normal motility
57waiting for at least 6 months is recommended. It is important to establish stability of the strabismus measurements before surgery is performedwaiting for at least 6 months is recommended.Half of the patients required repeated operationStrengtheningprocedures are rarely performed because they usually worsen restriction
58Adjustable sutures are helpful in these difficult cases. Slight initial undercorrection is desirable, because late progressive overcorrection is common, especially with large inferior rectus recessions.Nonabsorbable sutures may decrease the likelihood of overcorrection.Limited depression of the eyes after inferior rectus muscle recessions can interfere with bifocal use by patientsProptosis can become worse after extraocular muscle recessions.
59HintIf the need for orbital decompression is foreseeable, it is usually preferable to postpone strabismus surgery until that has been accomplisheLikewise, eyelid surgery usually is performed at a later time because upper eyelid retraction may be improved when the patient no longer strains to elevate the eye lid
60Large recessions of very tight inferior rectus muscles can cause lower eyelid retraction severe enough to require subsequent eyelid surgery. Severing the lower eyelid retractorsas part of the strabismus surgery has led to some success at preventing this complication.If necessary, a spacer of banked sclera or synthetic material can be placed to verticallylengthen the lower lid tarsus
62What kinds of surgery are done in patients with TRIO? Orbital decompressionEye muscle surgeryEyelid surgeryneeds to be done in this orderDecompression affects ocular motility and may alter muscle surgerymuscle surgery should be completed before eyelid surgery
63Which patients require orbital decompression? Optic nerve compression :EOM swelling with relatively little space at the apex of the orbitsqueezing of the optic nerve at the apex of the orbitSevere proptosis resulting in corneal exposure or disfigurement
65When do patients require muscle surgery? Double vision in functional fieldEnsure that the inflammation is quiet and the patient's motility pattern is stableRepeated stable measurements over 6+ months help to ensure that motility is stable
66What are the alternatives to muscle surgery? prisms in glasses works for patients with double vision and relatively small deviationsIt is better that the motility become stable before prisms are prescribedTemporary Fresnel prisms may be helpful during periods of instability
67Botulinum toxin A injection has a good effect in the treatment of restrictive strabismus in TAO. Early treatment has better results.Dosage in TAO is higher, the mean changes of degree of deviation is slighter, the interval between injections and the duration of effect is shorter.Injection dosage should increase after repeated injections.
68What type of muscle surgery is required? Recession of muscles, usually on an adjustable suture basisMuscles are tight and scarred, resection is not indicatedInferior and medical rectus muscles are the most common targetsForced duction test at the time of surgery is indicated
69Does eye muscle surgery affect the eyelids? Recession of the tight IRoften improves upper eyelid retraction:SR had to work against the tight IR, thus the associated levator muscle was overactive, causing eyelid retraction. When the IR is recessed, the overactivity relatively endsLarge recession of IR may worsen inferior lid retraction
70What kind of eyelid surgery is done? Eyelid retractionOrbital decompression lowers eye, improving the lower lid retractionMild lid retraction: recession of the eyelid retractors (upper or lower) is adequateSevere retraction: spacers are needed, such as hard palate in the lower lids and fascia in the upper lidsBlepharoplasty and/or brow liftExcessive skin from chronic swellingAt the same time or later date
79Myasthenia GravisOnset of myasthenia gravis may occur at any age but is uncommon in children.A transient neonatal form, caused by the placental transfer of acetylcholine receptor antibodies of mothers with myasthenia gravis, usually subsides rapidly.Another variety is not immune mediated and exhibits a familial incidence.
80The disease may be purely ocular (30%-50%) occurs as part of a major systemic disorderChildhood myasthenia gravis is more common in females.
81Clinical FeaturesThe principal ocular manifestation is extraocular muscle weakness, including weakness of the levator muscle.The majority of cases (90%) have both ptosis and limited ocular rotations.
82Ptosis typically increases when the patient is required to look upward for 30 secondsSleep test, ptosis often resolves after 20-30minutes in a dark room with the eyelids closed.Cogan twitchovershootof the eyelid when the patient looks straight ahead after looking down for severalminutes
83Neostigmine (Prostigmine) test Ice test Tensilon testNeostigmine (Prostigmine) testIce testExternal application of ice for 2-5 minutes improves function of the levator and otheraffected extraocular muscles, giving a rapid and reliable method of establishing this diagnosiswithout the need for drug administration.
84Electromyographyshows decreased electrical activity of involved muscles after prolonged voluntary innervation anincreased activity (including saccadic velocity) after the administration of edrophonium or neostigmine.Documentation of abnormalities in single-fiber electromyography or the presence of circulating antiacetylcholine receptor antibodies is confirmatoryalthough a negative result does not rule out the presence ofthis disease.