14 - Surgery of the EOMs

Question 1

Complications chx strabisme

Une diplopie en PO de chirurgie de strabisme est plus susceptible de se produire chez quelle population ?
Qu’est-ce qu’on peut faire comme test en pré-op pour tenter de prédire une diplopie qui persiste en PO ?

Answer 1

• Prolonged postoperative diplopia is uncommon. However, if strabismus was first acquired in adulthood, diplopia that was symptomatic before surgery is likely to persist unless comitant alignment and fusion are regained.
  ○ Prisms that compensate for the deviation may be helpful during the preoperative evaluation to assess the fusion potential and the risk of bothersome postoperative diplopia.

Question 2

Complications chx strabisme

Quelles sont les outcomes possible au niveau physiologique en PO de chx de strabisme ?

Answer 2

• In the several months following surgery, various responses are possible:
  ○ Fusion of the 2 images may occur.
  ○ A new suppression scotoma may form, corresponding to the new angle of alignment.
  If the initial strabismus was acquired before age 10 years, the ability to suppress is generally well developed.
  ○ Diplopia may persist.

Question 3

Complications chx strabisme

V ou F : avoir une vision plus faible d’un oeil est un facteur protecteur de diplopie PO ?

Answer 3

Vrai
A patient with unequal vision can often ignore the dimmer, more blurred image.

Question 4

Complications chx strabisme

Quels sont les traitements possible d’une diplopie symptomatique et persistante en PO de chx de strabisme?

Answer 4

Further treatment is indicated for patients whose symptomatic diplopia persists after surgery, especially if it is severe and present in the primary position.
* If vision in the eyes is equal or nearly so, temporary or permanent prisms should be tried to address any residual diplopia.
* If this approach fails, additional surgery or botulinum toxin injection may be considered.
* In some cases, intractable diplopia can be controlled only by occluding or blurring the less preferred eye with a MIN lens

Question 5

Complications chx strabisme

V ou F : l’alignement obtenu en PO de chez de strabisme est immobile dans le temps ?

Answer 5

F : Alignment in the immediate postoperative period, whether satisfactory or not, may not be permanent.

Question 6

Complications chx strabisme

Quelles sont les causes (3) d’un mauvais alignement PO de chx de strabisme?

Answer 6

poor fusion, poor vision, and contracture of scar tissue

Question 7

Complication chx strabisme

Une chirurgie sur quel MEO peut mener au syndrome d’anti-élévation ?

Answer 7

Inferior oblique anteriorization can result in restricted elevation of the eye in abduction, known as anti- elevation syndrome.

Question 8

Complications chx strabisme

Qu’est-ce qui augmente le risque de développer un syndrome d’anti-élévation en PO ?
Qu’est-ce qui le diminue ?

Answer 8

Reattaching the lateral corner of the muscle anterior to the spiral of Tillaux increases the risk of this syndrome
“Bunching up” the insertion at the lateral border of the inferior rectus muscle may reduce the risk.

Question 9

Complications chx strabisme

Quel est le MEO le plus difficile à aller retrouver lorsqu’il glisse ?

Answer 9

Medial rectus muscle

Question 10

Complications chx strabisme

Si on ne retrouve pas rapidement un muscle qui a glissé, quelle structure peut-on tenter d’aller voir pour nous aider à le retrouver ?

Answer 10

Minimal manipulation should be used to bring into view the anatomical site through which the muscle and its sheath normally penetrate the Tenon capsule where, it is hoped, the distal end of the muscle can be recognized and captured.

Question 11

Complications chx strabisme

Quel signe clinique peut nous aider à identifier un muscle lorsqu’on est pas trop sûr que c’est un MEO ?

Answer 11

If inspection does not reliably indicate that the muscle has been identified, sudden bradycardia when traction is exerted can be confirmatory.

Question 12

Complications chx strabisme

Selon quel délais on retourne en SOP lorsqu’on suspecte qu’un MEO a glissé en PO ?

Answer 12

Surgery should be performed as soon as posible in order to secure the muscle before further retraction and contracture take place.

Question 13

Complications chx strabisme

Qu’est-ce que le Pulled- in- Two Syndrome ?

Answer 13

Dehiscence of a muscle during surgery has been termed pulled- in- two syndrome (PITS).

Question 14

Complications chx strabisme

Où est-ce que la déhisence survient le plus souvent dans le pulled-in-two syndrome ?

Answer 14

The dehiscence usually occurs at the tendon– muscle junction

Question 15

Complications chx strabisme

Quel est le MEO le plus souvent impliqué dans le pulled-in-two syndrome ?

Answer 15

Inferior rectus

Question 16

Complications chx strabisme

FDR de développer un pulled-in-two syndrome ?

Answer 16

Advanced age, various myopathies, previous surgery, trauma, or infiltrative disease may predispose a muscle to PITS by weakening its structural integrity

Question 17

Complications chx strabaisme

V ou F : lors d’une perforation de la sclère, il est fréquent de développer un décollement de la rétine ?

Answer 17

Perforation can lead to retinal detachment or endophthalmitis
In most cases, it results in only a small chorioretinal scar, with no effect on vision. Most perforations are unrecognized unless specifically looked for by ophthalmoscopy.

Question 18

Complications chx strabisme

Qu’est-ce qu’on fait lorsqu’on voit du vitré sortir de la sclère ?

Answer 18

If vitreous escapes through the perforation site, many surgeons apply immediate local cryotherapy or laser therapy.
Topical antibiotics are generally given during the immediate postoperative period, even when vitreous has not escaped.

Question 19

Complications chx strabisme

V ou F : les infections sont fréquentes en PO de chirurgie de strabisme

Answer 19

Faux elles sont rares

Question 20

Complications chx strabisme

Quelles sont les infections possibles en PO ? Elles surviennent généralement combien de temps après la chx ?

Answer 20

Mild conjunctivitis develops in some patients and may be caused by allergy to suture material or postoperative medications, as well as by infectious agents.
Preseptal and orbital cellulitis with proptosis, eyelid swelling, chemosis, and fever are rare

These conditions usually develop 2–3 days after surgery and generally respond well to systemic antibiotics.

Question 21

Complications chx strabisme

Où se développe typiquement les granulomes pyogéniques en PO ?

Answer 21

typically develops at the conjunctival incision site

Question 22

Complications chx strabisme

V ou F : les granulomes pyogéniques nécessitent souvent qu’on les enlève

Answer 22

It is prone to ulceration or bleeding but usually resolves spontaneously.
Persistent lesions may require surgical excision.

Question 23

Complications chx strabisme

À quoi ressemble un kyste épithélial et pourquoi se développe-t-il ?

Answer 23

A noninflamed, translucent subconjunctival mass may develop if conjunctival epithelium is buried during muscle reattachment or incision closure

Question 24

Complications chx strabisme

Quelle est la prise en charge des kystes épithéliaux ?

Answer 24

• Occasionally, the cyst resolves spontaneously.
  
  • Topical steroids may be helpful
  • Persistent cases may require surgical excision.

Question 25

Complications chx strabisme

V ou F : an epithelial cyst may be incorporated into the muscle tendon

Answer 25

True
Careful exploration is mandatory to identify this complication.

Question 26

Complications chx strabisme

Signe d’un conjunctival scarring

Answer 26

the tissues remain hyperemic and salmon pink instead of returning to their usual whiteness.

Question 27

Complications chx strabisme

Conjunctival scarring can result from what mechanisms (2)

Answer 27

1. Advancement of thickened Tenon capsule too close to the limbus.
   * In resection procedures, pulling the muscle forward may advance the Tenon capsule. The undesirable result is exaggerated in reoperations, when the Tenon capsule may be hypertrophied.
2. Advancement of the plica semilunaris.
   * During surgery on the medial rectus muscle using the limbal approach, the surgeon may mistake the plica semilunaris for a conjunctival edge and incorporate it into the closure.
   * Though not strictly a conjunctival scar, the advanced plica, now pulled forward and hypertrophied, retains its fleshy color

Question 28

Complications chx strabisme

What are the options for the treatment of conjunctival scarring ?

Answer 28

Treatment options include conjunctivoplasty with resection of scarred conjunctiva and transposition of adjacent conjunctiva, resection of subconjunctival fibrous tissue, recession of scarred conjunctiva, and amniotic membrane grafting.

Question 29

Complications chx strabisme

Quelle est la cause du syndrome d’adhérence ?

Answer 29

Tears in the Tenon capsule with prolapse of orbital fat into the sub-Tenon space can cause formation of a fibrofatty scar that may restrict ocular motility.

Question 30

Complications chx strabisme

Quel muscle est le plus à risque de causer un syndrome d’adhérence ? Pourquoi ?

Answer 30

Surgery involving the inferior oblique muscle is particularly prone to this complication because of the proximity of the fat space to the posterior border of the inferior oblique muscle

Question 31

Complications chx strabisme

Qu’est-ce qu’un « Delle » ? Causé par quoi ?

Answer 31

A delle (plural dellen) is a shallow area of corneal thinning near the limbus.
Dellen occur when raised abnormal bulbar conjunctiva prevents adequate lubrication of the cornea adjacent to the raised conjunctiva

Question 32

Complications chx strabisme

Un delle est plus susceptible de se produire avec quelle approche chirugicale ?

Answer 32

Dellen are more likely to occur when the limbal approach to EOM surgery is used.

Question 33

Complications chx strabisme

V ou F : Dellen usually heal with time

Answer 33

They usually heal with time. Artificial tears or lubricants may be used until the chemosis subsides.

Question 34

Complications chx strabisme

What is the earliest sign of anterior segment ischemia ? Signs of the more severe cases ?

Answer 34

The earliest signs of this complication are cells and flare in the anterior chamber.
More severe cases are characterized by corneal epithelial edema, folds in the Descemet membrane, and an irregular pupil
This complication may lead to anterior segment necrosis and phthisis bulbi.

Question 35

Complications chx strabisme

Comment peut-on réduire les risque d’ischémie du segment antérieur ?

Answer 35

It is possible to recess, resect, or transpose a rectus muscle while sparing its anterior ciliary vessels. Though difficult and time consuming, this technique may be indicated in highrisk cases.
Staging surgery, with an interval of several months between procedures, may also be helpful.
Because the anterior segment is partially supplied by the conjunctival circulation through the limbal arcades, using fornix instead of limbal incisions may provide some protection against the development of ASI.

Question 36

Complications chx strabisme

PEC des ischémies du segment antérieur

Answer 36

No universally agreed upon treatment exists for ASI. Because the signs of ASI are similar to those of uveitis, most ophthalmologists treat with topical, subconjunctival, or systemic corticosteroids, although there is no firm evidence supporting this approach.

Question 37

Complications chx strabisme

Change in the position of the eyelids is most likely to occur with surgery on which muscles ?

Answer 37

Verticle rectus muscles, surtout le droit inférieur
Pulling the inferior rectus muscle forward, as in a resection, advances the lower eyelid upward; recessing this muscle pulls the lower eyelid down, exposing sclera below the lower limbus

Question 38

Complications chx strabisme

Qu’est-ce qu’on peut faire pour limiter un lower eyelid retraction after inferior rectus muscle recession ?

Answer 38

Release of the lower eyelid retractors or advancement of the capsulopalpebral head is helpful

Question 39

Complications chx strabisme

T or F : all intermuscular septum and fascial connections of the vertical rectus muscle must be severed at least 5 mm posterior to the muscle insertion to lower the risks of change in eyelid position

Answer 39

F : all intermuscular septum and fascial connections of the vertical rectus muscle must be severed at least 12–15 mm posterior to the muscle insertion.

Question 40

Complications chx strabisme

T or F : Changes in refractive error are most common when strabismus surgery is performed on 2 rectus muscles of an eye.

Answer 40

True

Question 41

Complications chx strabisme

T or F : Surgery on the oblique muscles can change the axis of preexisting astigmatism

Answer 41

True

Question 42

Anesthesia for EOM Surgery

Topical anesthesia is not effective for control of the pain of which manipulation ?

Answer 42

Topical anesthesia is not effective for control of the pain produced by pulling on or against a restricted muscle or for cases in which exposure is difficult.

Question 43

Anesthesia for EOM Surgery

Quel type d’anesthésie peut-on utiliser si notre patient a plein de comorbidités qui rendrait l’AG risqué ?

Answer 43

Both peribulbar and retrobulbar anesthesia make most EOM procedures painfree and should be considered in adults for whom general anesthesia may be risky

Question 44

Anesthesia for EOM Surgery

V ou F : les ansthésiants locaux influencent l’alignement durant les premiers jours PO ?

Answer 44

F : Because injected anesthetics may influence alignment during the first few hours after surgery, suture adjustment is best delayed for at least half a day.

Question 45

Anesthesia for EOM Surgery

Quels types d’agents utilisés par l’anesthésiste affecte les résultats du traction test ? Que peut-on utiliser comme alternative ?

Answer 45

Neuromuscular blocking agents such as succinylcholine, which are administered to facilitate intubation for general anesthesia, can temporarily affect the results of a traction test.
Nondepolarizing agents, which do not have this effect, can be used instead.

Question 46

Anesthesia for EOM Surgery

Moyens pour diminuer le risque de No & Vo PO ?

Answer 46

Eye muscle surgery is a risk factor for postoperative nausea and vomiting.
This risk can be reduced by :
* Prophylaxis with dexamethasone and serotonin type 3 (5HT3) antagonists (eg, ondansetron)
* Propofol use
* Adequate hydration
* Reduced use of inhalation anesthetics and opioid analgesia.

Question 47

Anesthesia for EOM Surgery

Quel muscle est le plus à risque de déclencher un réflexe oculocardiaque ?

Answer 47

Medial rectus

Question 48

Anesthesia for EOM Surgery

Quel RX peut éliminer le risque de produire un réflexe oculocardiaque ?

Answer 48

Atropine IV

Question 49

Anesthesia for EOM Surgery

Est-ce que l’hyperthermie malgine est plus à risque de se produire lors de chx pédiatrique ? Pourquoi ?

Answer 49

Malignant hyperthermia (MH) is an important disorder for pediatric ophthalmologists because of its association with strabismus, myopathies, ptosis, and musculoskeletal abnormalities.

Question 50

Anesthesia for EOM Surgery

Hyperthermie malgine : transmission = ?

Answer 50

It can occur sporadically or be dominantly inherited with incomplete penetrance.

Question 51

Anesthesia for EOM Surgery

Pathophysiologie de l’hyperthermie maligne

Answer 51

MH is a defect of calcium binding by the sarcoplasmic reticulum of skeletal muscle.
When MH is triggered by inhalational anesthetics or the muscle relaxant succinylcholine, unbound intracellular calcium concentration increases. This stimulates muscle contracture, causing massive acidosis. In its fully developed form, MH is characterized by extreme heat production, resulting from the hypermetabolic state.

Question 52

Anesthesia for EOM Surgery

Premier signe de l’hyperthermie maligne ?

Answer 52

Unexplained elevation of end tidal carbon dioxide concentration

Question 53

Chemodenervation

Quel type de botulinum toxine on utilise pour les injections ?

Answer 53

Type A

Question 54

Chemodenervation

Méchanisme d’action Botulinum toxine type A ?

Answer 54

Paralyzes muscles by blocking the release of acetylcholine at the neuromuscular junction.

Question 55

Chemodenervation

Après combien de temps le botox est internalisé dans les nerfs moteurs ? On peut voir l’effet d’une injection de botox après combien de temps et pourquelle période ?

Answer 55

Within 24–48 hours of injection, botulinum toxin is bound and internalized within local motor nerve terminals, where it remains active for many weeks.
Paralysis of the injected EOM begins within 2–4 days of injection and lasts clinically for at least 5–8 weeks.

Question 56

Chemodenervation

Le botox produit une récession ou une résection du muscle injecté ?
Que se passe-t-il avec le muscle antagoniste ?

Answer 56

This produces a pharmacologic recession: the EOM lengthens while it is paralyzed by botulinum toxin, and its antagonist contracts.

Question 57

Chemodenervation

V ou F : une injection de botox produit des changements à court terme, jusqu’à la fin de l’effet thérapeutique

Answer 57

F : Changes after injection may prouce longterm improvement in the alignment of the eyes

Question 58

Chemodenervation

Quelle molécule peut-on injecter dans le muscle antagoniste pour produire une résection chimique et augmenter la durée de la correction ?

Answer 58

The recent introduction of bupivacaine injection into the antagonist muscle to provide a chemical resection effect may extend the durability of the correction and expand the range of deviations in which chemodenervation can be successfully used**

Question 59

Chemodenervation

Pour quelles pathologies l’injection de botox est-elle la plus efficace ?

Answer 59

• Small to moderate angle esotropia and exotropia (<40Δ)
• Postoperative residual strabismus (2–8 weeks following surgery or later)
• Acute paralytic strabismus (especially sixth nerve palsy; sometimes fourth nerve palsy), to eliminate diplopia while the palsy resolves
• Active thyroid eye disease (Graves disease) or inflamed or prephthisical eyes, when surgery is inappropriate
• As a supplement to medial rectus muscle recession for large angle infantile esotropia or lateral rectus muscle recession for large angle exotropia

Question 60

Chemodenervation

Pour quelles pathologies l’injection de botox n’est généralement pas efficace ?

Answer 60

• patients with large deviations
• restrictive or mechanical strabismus (trauma, chronic thyroid eye disease)
• secondary strabismus wherein a muscle has been overly recessed
• A and V patterns
• DVDs
• Chronic paralytic strabismus

Question 61

Chemodenervation

V ou F : With botox injection, results are best when there is fusion to stabilize the alignment

Answer 61

True

Question 62

Chemodenervation

ES les plus communs du botox ?

Answer 62

The most common adverse effects of ocular botulinum toxin treatment are ptosis, lagophthalmos, dry eye, and induced vertical strabismus after horizontal muscle injection

Question 63

Chemodenervation

Quelles sont les complications graves et rares de l’injection de botox ?

Answer 63

Rare complications include scleral perforation, retrobulbar hemorrhage, pupillary dilation, and permanent diplopia.

Question 64

Chemodenervation

Est-ce que lebotulinisme systémique survient souvent en ophtalmo ?

Answer 64

Systemic botulism has been reported in animals and humans following massive injections of large muscle groups, but this has not been encountered in ophthalmologic use of botulinum toxin

Question 65

Options chirurgicales pour un large angle esotropia (>60 Δ) ?

Answer 65

• Combined recession-resection of 3 or 4 horizontal rectus muscles
• Bilateral medial rectus muscle recessions of 7.0 mm.
• Augmentation of the latter with botulinum toxin has been advocated.

Question 66

Options chirurgicales d’un large angle exotropia (> 40Δ) ?

Answer 66

• Bilateral lateral rectus muscle recessions of 9.0 mm or greater
• Others prefer to limit lateral rectus recession to no more than 8.0 mm and add resection of 1 or both medial rectus muscles
• Unilateral surgery for exotropia beyond the given values (ie, >40Δ) is likely to result in a limited rotation; thus, a 3 or 4 muscle procedure is preferable if there is at least moderately good vision in each eye

Question 67

What is the goal when operating an incomitant deviation ?

Answer 67

• When the size of the deviation varies in different gaze positions, the surgical plan should be designed with a goal of making the postoperative alignment more comitant.

Question 68

What should we suspect as the cause of horizontal incomitance ? (3)

Answer 68

Paresis, paralysis, or restriction is suggested

Question 69

When you have a weak muscle as the cause of an incomitant strabismus, what are you surgical options ?

Answer 69

If the weak muscle exhibits little or no force generation, transposition procedures are usually indicated. Other wise, treatment consists of some combination of resection of the weak muscle (or advancement if it has been previously recessed) and weakening of its direct antagonist or yoke muscle.

Question 70

Avec quel test peut-on différencer une restriction d’une faiblesse ?

Answer 70

Forced duction and active force generation testing are helpful

Question 71

On opère quel muscle lorsqu’on a une déviation plus grande à distance ? Plus grande en vision de près ?

Answer 71

Medial rectus muscle surgery for deviations greater at near
Lateral rectus muscle surgery for deviations greater at distance (loin = lateral)

Evidence suggests that, regardless of which muscles are operated on, the improvement in distance– near incomitance is similar.

Question 72

Dans un strabisme cyclovertical, on opère quel muscle ?

Answer 72

In general, surgery should be performed on those muscles whose field of action corresponds to the greatest vertical deviation unless results of forced duction testing reveal contracture that requires a weakening procedure for a restricted muscle.