Lateral Rectus Muscle Strangulation: A New Weakening Technique in Cases of Exotropia
Phase: NA
Conditions: Strabismus, Divergent
Sponsor: Sohag University

Lateral rectus muscle strangulation: a new weakening technique in cases of 
exotropia
 
Introduction:
 
 )
(1
 
"eyes looking obliquely" and misaligned.
 
means
 
a Greek word that
 
is
Strabismus 
 
)
(2
, strabismic eyes are "squinting eyes," "crossed eyes,"
So
 
) 
(3,4
 
prevalence is 2% to 5% in the general population.
Its 
 
The pathogenesis of squint is not completely clear. Ocular motility involves extraocular 
muscles, cranial nerves, supranuclear pathways, and their cerebral controls. All can be 
implicated in the development of squint. The most popular theories are: 
 
Claude Worth's theory: an inherent absence of cortical fusional potential is considered 
the cause. (5) 
 
Chavasse theory: motor alignment leads to a poor sensory status, which, if un-treated, 
leads to squint. This makes clear that early treatment for squint will lead to sustained 
improvement in binocular single vision (BSV). (6)  
About muscle action, there are 2 laws of ocular motility: 
 
Sherrington's law of reciprocal innervation: Increased innervation to a muscle is 
accompanied by decreased innervation to its antagonist. Exception: Duane retraction 
syndrome. (7)                                             
 
Herring law of equal innervation: Equal and simultaneous innervation flows through 
synergistic muscles during any conjugate eye movement. Exception: Dissociated 
vertical deviation. (8)  
Heterophoria is defined as an ocular deviation kept in control by a fusional 
mechanism. Heterotropia is defined as the deviation that is present on the corneal 
reflex test itself. This is the manifest deviation that can be related to underlying 
amblyopia (6) 
Exotropia - This is a divergent strabismus in which the eyeball deviates temporally. 
(1)     
aims are to treat 
is to restore proper ocular alignment. The secondary 
ment 
aim of treat
 
main
The 
re are many 
The
 
if present.
 
, and eliminate diplopia
single vision
 
amblyopia, maintain binocular
)
(9 
are:
which 
of treating strabismus 
 
odalities
m
 
correction, 
orthoptics, prismatic 
 
Observation, correction of refractive errors, amblyopia treatment,
which either: weakening procedure, strengthening 
 
(9)
 
botulinum toxin and extraocular muscle surgery
 )
(10
 
procedure and vector adjustment procedure (transposition procedure)
 
weakening of the extra ocular muscle is used to decrease the effective strength of muscle 
action. (11) In 1922, Jameson introduced the scleral suturing technique (muscle recession) as a 
graded method for extraocular muscle weakening. (11) 
Then many weakening procedures have been described. Muscle recession is still the standard 
and often most commonly used technique in which we disinsert the muscle from its original 
insertion and moving it posteriorly away from the limbus. (12) there are many complications 
from this surgery related to suturing and muscle disinsertion. (12) 

Other weakening procedures are retro equatorial myopexy or posterior fixation (Faden 
procedure), marginal myectomy, and myectomy (disinsertion). (13) 
Recently, extra ocular muscle fenestration is considered as a new surgical technique for 
weakening of the extraocular muscles without using sutures or botulinum toxin. (13) 
The fenestration technique weakens the muscle by removing a block of the muscle close to its 
insertion which is done in between 2 peripheral muscle strips. It is a promising simple 
technique that might avoid the complications of using sutures such as foreign body reactions 
and granuloma formation. (14)  
The disadvantage of muscle fenestration as it is irreversible maneuver. So, we modify anew 
technique which is muscle strangulation in which we strangulate a block of muscle near to its 
insertion using proline 10/0 so it will be weakened by this technique and this part will act as a 
tendon. 
This study is aiming to evaluate the efficacy and safety of strangulation as a weakening 
maneuver to horizontal extra ocular muscle ( lateral rectus muscle) in the surgical 
management of exotropia. 
Material and methods: 
Ethical consideration: 
This study will obtain approval of the Ethics Committee of the Research Institute of 
Ophthalmology, Sohag, Egypt, and it is conducted in accordance with the Declaration of 
Helsinki. A written informed consent will be taken from each patient or his/her guardians (if 
the patient was unable to participate in the consent process). 
Type of study: Case- Series study. 
Inclusion criteria: cases of exotropia which are not recurrent nor consecutive. 
Exclusion criteria: 1- recurrent cases. 
2- consecutive cases  
3- paralytic and restricted muscle.  
Interventions: After sterilization and draping of the eyes, an eye speculum 
is inserted. The muscle is exposed and hooked through either a fornix-based or limbal-based 
incision. Careful dissection is carried out to delineate the muscle edge, a previously measured 
blook of the lateral rectus muscle is sutured ( strangulated) with proline 10/0.  
 

Statistical analysis: 
The statistical analyses of the research data were carried by making use of SPSS V.26 (IBM 
Inc., Chicago, IL, United states of America). Quantitative data were supplied in the form of 
mean and standard deviation. 
 
 
 
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ye 
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