HISTORY:
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| Robert Marcus Gunn |
The condition was first described by Robert Marcus Gunn, M.A., M.B.Edin., F.R.C.S.Eng, in the year 1883. Who was then working as the assistant surgeon to the Moorfields Hospital and Ophthalmic surgeon to the Hospital for sick Children.He described a 15yr old girl with a peculiar type of congenital Ptosis that included an associated winking motion of affected eye lid on the movement of jaw.
His official obituary can be found at OBITUARY
MARCUS GUN JAW-WINKING PHENOMENON:
The wink phenomenon i.e., retraction of the ptotic lid occurs in conjunction with stimulation of pterygoid muscle, which is elicited by opening the mouth, thrusting the jaw to the contralateral side, jaw protrusion, chewing, smiling or sucking.
This wink phenomenon is often discovered early, as the infant is bottle-feeding or breastfeeding. You can clearly see in the video below the retraction of the ptotic lid on sucking.
PATHOPHYSIOLOGY:
There are several theories that have been hypothesized to explain the pathophysiology of the phenomenon.
1. Aberrant Connection: This is the most popular hypothesis, but there is no consensus on the location of the aberration.
a) Cortical or sub cortical connections.
b) Internuclear connections or faulty distribution in the posterior longitudinal bundel.
c) Infranuclear connection exists between motor branches of the trigeminal nerve (CN V3) innervating the external pterygoid and the fibers of superior division of the oculomotor nerve (CN III) that innervates the levator muscle of the upper lid.
d)Peripherally - some CN V fibers may reach the levator via the auriculo- temporal nerve.
a. Irritation of normally dormant connection
b. Disinhibition of pre-existing phylogenetically more primitive mechanisms (Ascher): This is thought to explain why individuals who are not affected will often
open their mouth while attempting to widely open their eyes to place eye drops
c. Spread of impulses by irradiation
3.Atavistic Reversion
a. In fish a strong associated movement of jaw opening and eye opening i.e., deep muscle contracting and superficial muscle relaxing. Thus a weak levator may only elevate the lid when its antagonist, the orbicularis (superficial muscle) is reflexly relaxed by jaw opening (external pterygoid-deep muscle contraction )
b. EMG study suggested dysfunction in the midbrain and
brainstem
GENETICS:
Jaw-winking ptosis is almost always sporadic, but familial cases with an irregular autosomal dominant inheritance pattern have been reported.
FREQUENCY:
Approximately 50% of blepharoptosis cases are congenital.Incidence of Marcus Gunn jaw-winking syndrome among this population is approximately 4-5%.
ASSOCIATIONS:
1. OCULAR
A. Strabismus (50%-60%)
1. Superior Rectus Palsy-25%
2. Double Elevator Palsy-25%
B. Anisometropia (5%-25%)
Incidence of anisometropia among patients with Marcus
Gunn jaw-winking syndrome is reported to be 5-25%.
3. Amblyopia (30-60%)
Almost always secondary to strabismus or anisometropia,
and only rarely, is due to occlusion by a ptotic eyelid.
2. SYSTEMIC
Systemic anomalies in association with Marcus Gunn
phenomenon are rare.
1. Cleft lip/ Cleft palate
2. CHARGE Syndrome reported in association with bilateral cases.
3. Renal calculi (Awan 1976)
RACE:
No known racial predilection exists.
SEX:
Early reports showed jaw-winking ptosis to be more prevalent in females than in males; however, larger case series have shown an equal prevalence among males and females.
AGE:
Marcus Gunn jaw-winking syndrome is usually evident at birth. The winking phenomenon is often first noted by the parents when the infant is feeding.
TREATMENT:
1. Medical Care
If amblyopia is encountered, treat aggressively with occlusion therapy and/or correction of anisometropia prior to any consideration of ptosis surgery.
2. Surgical Care
As with any patient who requires eyelid surgery, first address associated strabismus.
1. Superior rectus palsy
Superior rectus palsy can be corrected by resecting the superior rectus muscle but only in the absence of inferior rectus restriction. Since the superior rectus is loosely bound to the overlying levator, the upper eyelid will be pulled inferiorly during resection, exacerbating any ptosis already present. This can be addressed during the subsequent ptosis repair.
2. Double elevator palsy
Double elevator palsy manifests as a deficit in the elevation of the globe in all fields of gaze. It may be the result of superior rectus and inferior oblique palsy and/or inferior rectus restriction. Inferior rectus restriction may be suggested by the following:
a. Positive forced duction in elevation.
b. Normal force generations in up gaze indicating an absence of superior rectus or inferior oblique palsy.
c. Poor or absent Bells phenomenon on the affected side
Inferior rectus restriction is treated by recession of the inferior rectus muscle.
A combined superior rectus and inferior oblique (double elevator) palsy requires a transposition procedure to displace the medial and lateral recti muscles superiorly (Knapp's Procedure).
3.Consider eyelid surgery only when the parents (or the patient) and the surgeon agree about whether the most cosmetically objectionable condition is the ptosis or the jaw winking or whether it is a combination of both.
4. Many techniques are described for the correction of jaw winking ptosis, reflecting the ongoing controversy regarding the surgical management of this condition.
5. If the jaw-winking is cosmetically insignificant, it can be ignored in the treatment of the ptosis. If the ptosis is mild, the patient may elect not to proceed with surgery. If correction is desired, perform a Muller muscle and conjunctival resection (MMCR), a Fasanella-Servat procedure :
or a standard external levator resection.
If the ptosis is moderate to severe, a levator resection may be indicated. Beard advocated performing more resection than normal to avoid undercorrection.
In severe ptosis, a super maximum (>30 mm) levator resection or frontalis suspension is necessary.
6. Although the amount of ptosis and synkinetic eyelid movement is variable, those patients with more severe ptosis tend to have the worse aberrant upper eyelid movement.
7. The jaw-wink is considered cosmetically significant if it is 2 mm or more.
8. Any attempt to repair the ptosis without addressing the jaw winking
would result in an exaggeration of the aberrant eyelid movement to a level well above the superior corneal limbus, which would be unacceptable to the patient.
9. Several techniques have been suggested to obliterate levator function, which effectively dampens the aberrant eyelid movement.
Bullock advocated complete excision of the levator aponeurosis and muscle all the way to the orbital apex.
Dillman and Anderson argued that removal of a portion of the levator muscle above the Whitnall’s ligament (i.e., myectomy) is adequate to obliterate its function without extensive dissection and damage to eyelid structures.
Bowyer and Sullivan describe the removal of a portion of levator muscle above the Whitnall ligament through a posterior conjunctival approach.
Dryden et al proposed suturing the transected levator aponeurosis to the arcus marginalis of the superior orbital rim. This technique not only effectively deactivates the muscle but also allows the procedure to be reversed, if necessary.
10. Beard and others have advocated bilateral excision of the levator muscle and bilateral frontalis suspension. While this approach almost completely eliminates the wink and arguably results in better symmetry, it is often difficult to persuade the parents and the patient to perform surgery on and effectively damage the normal contralateral levator muscle.
11. Satisfactory and predictable results also can be obtained after only unilateral levator excision on the affected side, combined with bilateral frontalis suspension (Callahan).This leaves the normal functioning levator muscle to elevate the non ptotic eyelid in primary position but produces a lag in downgaze for improved symmetry.
12. Kersten et al advocate unilateral levator muscle excision and frontalis sling only on the affected side. If the postoperative result is judged to be unsatisfactory, the parents or the patient can opt for further surgery to the contralateral side. Any amblyopia and strabismus should first be addressed, as there may be insufficient drive to lift the disinserted eyelid.
13. Islam et al described a technique of dissecting a frontalis flap hinged superiorly through a suprabrow incision that is then brought down into an eyelid crease incision. The frontalis flap is used to suspend the ptotic eyelid after extirpation of the levator muscle.
14. Lemagne and Neuhaus described techniques that involve transection of the involved levator followed by transposition of the distal segment to the brow, which effectively suspends the eyelid to the frontalis muscle. Their techniques maintain normal eyelid contour, as the levator aponeurotic attachments are left undisturbed.
Article based on Marcus Gunn Jaw-Winking Phenomenon : A Review, DJO Vol. 21, No. 3, January-March 2011 18-21
