COMMONWEALTH ASSOCATION FOR
EDUCATION, ADMINISTRATION AND
MANAGEMENT
VOLUME 2 ISSUE 3
ISSN NO 2322- 0147
MARCH
2014
Pterygium Surgeries And Changing Trends: A
Review
Excellence International Journal of Education and
Research (Multi- subject journal)
Excellence International Journal Of Education And Research
VOLUME 2
ISSUE 3
ISSN 2322-0147
Pterygium Surgeries And Changing Trends: A Review
By
Dr. Abdul Waris
MS,FICO(UK),FICS(USA)
FRCS (GLASGOW),FRCSED
VR Surgeon&faculty
Institute of ophthalmology,AMU
ALIGARH(202001)
Waris_eye@yahoo.co.in
Dr Naheed Akhtar
Senior Ophthalmic Consultant
Gandhi Eye Hosptital
Ramghat Road
Aligarh Uttar Pradesh
Dr. Nadim Khan
Resident doctor
Institute of ophthalmology, AMU
ALIGARH(202001)
Email Id: madinkaj@gmail.com
Abstract
To call pterygium a perennial thorn in physicians’ sides would be an
understatement. They’ve been fighting the condition for thousands of years,
judging by pterygia’s appearance in Egyptian hieroglyphics. Thankfully,
techniques have advanced greatly since then, and surgeons say pterygium
recurrence rate is very low when the proper techniques are used.This review
article, shares time-tested techniques for removing pterygia and reducing its rate of
recurrence.
Key Words
Pterygium,Hieroglyphics, Techniques,Cornea,Conjunctiva
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Introduction
Pterygium is a growth of fibrovascular tissue on the cornea, which appears to
becontinuous with the conjunctiva.1 Prevalence rates range from 0.7% to 31% in
variouspopulations around the world, and the condition is more common in warm,
dry climates.2
In general, conservative therapy for pterygium iswarranted unless one of the
following circumstances arises: loss of visual acuity eitherbecause of induced
astigmatism or encroachment onto the visual axis, marked cosmeticdeformity,
marked discomfort and irritation unrelieved by medical management, limitationof
ocular motility secondary to restriction, or documented progressive growth
towardthe visual axis so that ultimate loss of vision can reasonably be assumed. In
such circumstances,surgical intervention is required. Because recurrences after
pterygia excision arefrequent and aggressive, firm indications for surgical removal
should exist before primaryexcision. The fact that numerous different techniques
exist for the surgical treatment ofpterygium underscores the point that no single
approach is universally successful.3
The recurrence of pterygium after surgical treatmentremains a problem. The
criterion for recurrence is determined to be the invasion of cornea more than 1 mm
in diameter beginning from the limbus by fibrovascular tissue derived from the
surgery site.4–6 Because of the difficulty of controllingthis condition, various
treatment modalities includingradiotherapy, antimetabolite or antineoplastic
drugs,conjunctival flap, and conjunctival or limbal autografttransplantation have
been proposed.6 Generally, pterygiumrecurrences occur during the first 6 months
after the surgery.7 A number of factors such as type of pterygium, ageof patient,
environment, and surgical technique may beresponsible.6
Various surgical techniques
Bare sclera technique
Demireller and colleagues reported 8 (42%) recurrencesin 19 eyes treated by bare
sclera technique.8 Youngsondeclared the pterygium recurrence rate as 37% in 100
caseswith the same technique, and concluded that this process isunhealthy and
should not be used.9This technique is not recommendedworldwide because it has
no advantages other than beingsimple and time-saving.
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Use of mitomycin C
Mitomycin C is an antibiotic isolated from Streptomyces caespitosis. It inhibits
RNA, DNA, and protein synthesis andis usually used in systemic anticancer
therapy. Kunitomoand Mori first described the topical use of mitomycin C
toprevent pterygium recurrence in 1963 in Japan.7 Variousconcentrations of
mitomycin C with different durationsof application have been used, but the
minimal safe andeffective dosage and application time are still not
certain.10Rubinfeld and colleagues revealed reports of scleral ulceration,necrotizing
scleritis,
perforation,
iridocyclitis,
cataract,infection,
glaucoma,scleral
calcification, and loss of aneye after pterygium excision with adjunctive mitomycin
Ctherapy. While the exact incidence of these complicationsis unknown, the safety
of mitomycin C therapy remains tobe determined with future long-term trials.11
After surgicalexcision, placing mitomycin C is a simple and time-savingmethod
with a low recurrence rate. Nevertheless it has somedose-dependent complications,
which can develop at anytime. Patients should be followed up for a long time.
Rotational conjunctival flaps
Rotational conjunctival flaps to cover the pterygiumexcisional site have been
employed since the 1940s.3 Thereported recurrence rates range from less than 1%
to morethan 5%. Minimal to no complications apart from flap retractionand cyst
formation have been reported.12 McCoombesand colleagues recently reported a
recurrence rate of 3.2%by using a sliding conjunctival flap after primary
pterygiumexcision in 258 eyes with an 86% follow-up rate for aminimum of 1
year.13 The mostfrequent symptom after this procedure is the formation offolds
over the conjunctiva as a result of rotated tissues in the sliding flap area. Although
these folds cause bad cosmesis,including hyperemia at the begining, after a time
the conjunctivaimproves and reaches an acceptable level cosmetically.Conjunctival
flap tissue that is placed over bare sclera isadjacent to the excised pterygium tissue,
and changed limbalcells that might be localised on the flap could contribute tothe
development of recurrence.
Conjunctival autograft transplantation
Conjunctival autograft transplantation was first describedas a treatment for
pterygium by Kenyon and colleagues in1985.14 Starc and colleagues used this
method on 57 eyes of54 patients, nearly 80% of which were recurrent. The
meanfollow-up of 2 years detected only three (5.3%) recurrencesafter autograft
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transplantation and found a 7.3% secondaryrecurrence in patients with recurrent
pterygium.15 Güler andcolleagues observed all of recurrent cases (13.3%),
whichwere followed up after autograft transplantation, in the under40 year age
group16. These results suggest that the recurrencerate was highest in the 40–50 year
age group (42.30%)in our series. There was no statistically significant
differencebetween groups younger or older than 40 years. Starck andcolleagues
proposed that the efficient size of the autograftdecreases the recurrence rate and
this thesis is supported by Allan and colleagues.15,17
Some authors prefer lowerbulbar conjunctiva for autografting, considering that
anautograft from superior bulbar conjunctiva might cause problemsin probable
filtration surgery.18Syam and colleaguesreported a recurrence rate of 3.3% in a
study of 27 eyes. Recurrences are found to develop within 3 months aftersurgery.
Conjunctival scar ,hemorrhage under the autograft, corneal delennear the limbus,
and epithelial inclusion cysts are other complications.19
Koç and colleaguesdemonstrated that autografting from superior or inferior
inprimary cases caused no significant difference in recurrence,but in recurrent
pterygia, autografting from inferior resultedin a higher recurrence tendency (p =
0.166).20
Complicationsresulting from conjunctival autografting are rare and are nothreat to
vision. Allan and colleagues encountered one tenongranuloma, one conjunctival
inclusion cyst, and threewound dehissence in a series of 93 cases, and
concludedthat the conjunctival autografting technique results in lowercomplication
rates.17 Vrabek and colleaguesreported subconjunctival fibrosis at the autografting
region in2 cases, one of whom developed concommitant diplopia dueto extraocular
muscle restriction.21 Topical corticosteroidsare suggested in order to prevent
fibrosis. In most studiesof autografting, retrobulber anesthesia was performed,
whichwas reported to be one of the disadvantages of this technique.
The disadvantages of the conjunctivalautografting technique could be resolved as
follows: along operation time, the need for retrobulber anesthesia insome cases,
limitation of the autograft diameter from theconjunctiva, and can cause problems
in a probable fitrationsurgery. One of the other disadvantages of suturing
ispostoperative pricking. This effect might be minimized byplacing the knot under
the conjunctiva or using continuoussuturing. In spite of all these difficulties, the
recurrence rateis lower with this technique. After the operation, a smooth,white
surface is achieved cosmetically. The disadvantageof the long operation time
becomes an advantage with alow recurrence rate and no need for additional
surgicalintervention. As these are the most desired aims of surgery,the conjunctival
autografting technique therefore deservesclear recognition.
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Amniotic Membrane Grafts
Moreover, for those withadvanced pterygia with wide conjunctival involvement
ormultiple heads, conjunctival autografts might be limited bythe lack of remaining
healthy tissue in the same or fellow eye.
For these reasons, an alternative tissue source has beensought. Many authors have
reported that amniotic membranegrafts are a viable alternative to conjunctival
autograftsin reducing recurrences after pterygium excision. Thepossible
mechanisms of preventing pterygium recurrenceinclude promotion of conjunctival
epithelium, inhibition ofinflammation by inhibiting chemokine expression by
fibroblasts22-32and interleukin-1 expression by epithelial cells, andinhibition of
neovascularisation by inhibiting vascularendothelial cell growth.The amniotic
membrane is known to contain a thickbasement membrane and a vascular streamed
matrix.The basement membrane facilitates migration ofepithelial cells, reinforces
adhesion of basal epithelial cells, promotesepithelial differentiationand prevents
epithelial apoptosis.33,34Collectively, these actions explain why the
amnioticmembrane permits rapid epithelialisation.
Although amniotic membrane graftsare less proficient than conjunctival autografts
in reducingrecurrences after pterygium excision, it indicates that thistechnique
could be considered as an alternative in thesurgical management of pterygia,
especially when the baresclera technique alone has an unacceptably high
recurrence,35and complications related to mitomicin-C as an adjunctivetreatment
are a concern.
Summary
In conclusion, even in treating primary pterygium, additional methodsshould be
used. When possible complications and morbidityare taken into account in the
selection of this additionalmethod, Conjunctival autograft should be considered as
the first choice for pterygium excision even if there is a recurrence. The amniotic
membrane graft can also be considered to be the first choice for those with
advanced and diffuse conjunctival involvement (bi-head) or those who might like
to preserve the donor bulbar conjunctiva for a prospective glaucoma-filtering
procedure.
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Disclosure
The authors report no conflicts of interest.
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