Pterygium is a triangular shaped degenerative fibro vascular
encroachment of sub conjunctival tissue on to the cornea, and is made up of a
cap, head and body and more frequently located on the temporal side rather than
nasally. It is one of the common eye diseases of our region1. Corneal
epithelium is being constantly replaced by healthy cells originating from
limbal stem cells. These cells are supposed to resist growth of conjunctival
vascular tissue over the cornea. UV light damages stem cells in exposed limbal
area resulting in abnormal cells that cannot resist growth of conjunctival
vessels. Hence long term exposure to sunlight, especially ultraviolet rays,
UV-A and -B (290-400 nm) is considered the main cause2. It is also
more common in tropical areas where environment is hot, dry, windy and dusty3.
Elastotic degenerations of sub-epithelial conjunctiva most frequently occur
when we do histopathology4. Anti inflammatory drugs and lubricating
drops have some important role in reducing the patient discomfort but they
don’t treat the actual disease. Ablation by YAG laser and smoothening the
surface of the cornea by applying excimer laser has been tried but the results
are not so favourable5.
Indications of surgery are decreased vision, cosmetic problems,
muscle damage, inflammation and problems with contact lens wear6. Surgical
treatment is the treatment of choice if pterygium is progressive in nature7.
Simple excision (the technique in which sclera is left bared) is sometimes
associated with very higher chances of recurrence (up to 80%) that is usually more
aggressive than the primary lesion8. Previous and current surgical
management includes simple excision with or without Beta irradiation, intra-operative
and postoperative mitomycin C4,9, 5-FU9, amniotic
membrane grafting and different maneuvers of conjunctival grafting3,5,10.
However autologous conjunctival stem cells grafting proved to be the best
method, that gave low recurrence rate and as well as high safety10.
In 1985 Kenyon, first time described conjunctival autograft. They reported that
there are relatively minor complications with conjunctival cell grafting. But
when you compare conjunctival grafting with bare scleral technique the surgical
time is more prolonged. But these disadvantages are out weighted now. Due to
lack of sight threatening complications and the relatively low recurrence rate,
this procedure gained popularity in many centers. Limbal-conjunctival stem
cells grafting with limbus sutures looks to be an effective and safe operation
for decreasing the recurrence rate after pterygium excision11 due to
replenishment of normal corneal epithelial cells by the stem cells. In one
study (12.9%) recurrence is seen out of 41 patients with limbal conjunctival
stem cells autograft for primary pterygia03 so prevention of
pterygium recurrence (87.1%) is significant.
In
previous studies pterygium recurrence with limbal conjunctival auto grafting in
primary pterygia is as high as 39%13 (efficacy61%) out of 52
patients to as low as 1.9%12(efficacy 98.1%) out of 30 patients so
we need to address this variability in results. So to the best of my knowledge
no study previously has taken such a larger sample size of limbal stem cells
autograft technique in primary pterygia cases specifically to estimate the true
efficacy of this technique and correct the variability of previous results.
MATERIAL AND METHODS
It was Descriptive, Case Series study. The study was done at
Ophthalmology department of Mayo Hospital Lahore. The duration of study was 8
months from January 2013 to August 2013. Patients of both gender with ages
between 20 – 60 years having primary pterygium encroaching cornea up to 2 mm
from the limbus on slit lamp examination and causing discomfort, visual
impairment or cosmetic disfigurement were selected. Patients who were excluded
were those having pseudopterygium, active ocular infection and recurrent
pterygium.
Approval from the hospital ethical committee was taken for all 120
cases who presented in OPD of Ophthalmology department, Mayo Hospital, Lahore.
Informed consent was taken from each patient meeting the inclusion criteria,
explaining to them the purpose and procedure of the study and ensuring the
confidentiality of information. Participants were also told that there was no
risk of participating in this research. Moreover; early detection of this
complication carried a potential benefit of good treatment results. After
Informed consent, personal profile of all patients (name, age, sex, and postal
address) and eye having pterygium was noted.
Procedure was done under topical anaesthesia. Conjunctiva was
dissected away from pterygium, excision of the pterygium mass was done avoiding
damage to the medial rectus muscle. Conjunctival limbal stem cell autograft was
then taken from superior limbus and stitched on excised area at limbus. All
procedures were done by one consultant ophthalmologist. After the procedure,
combination of topical steroid antibiotic drops was used and pad was applied
for 48 hours. This combination of drops was continued for a month four times a
day and then tapered off.
Follow
up with slit lamp examination of patients was done at 6 months post-operatively
for recurrence of pterygium (fibrovascular re-growth crossing the
corneo-scleral limbus by 1.0 mm or more). All data was collected on pre-designed
Performa which contained two parts i.e. part one contained patient’s bio-data
while part two contained study variables.
RESULTS
Age range in this study was from 20 to 60 years with mean age of 41.18 ± 11.03 years. Majority of the patients i.e. 38 (31.67%) were
between 41 to 50 years of age as shown in Table I.
Table 1: % age of participants according to Age
distribution (n=120).
|
Age (in Years) |
No. of Patients n (%) |
|
20 – 30 |
23 (19.17) |
|
31 – 40 |
35 (29.17) |
|
41 – 50 |
38 (31.67) |
|
51 – 60 |
24 (20.0) |
|
Total |
120 (100.0) |
Mean ± SD = 41.18 ± 11.03 years
Out of
these 120 patients, 79 (65.83%) were male and 41 (34.67%) were females with
ratio of 1.9:1 respectively (Figure 4).
All the selected patients then underwent limbal stem cell
autograft technique for pterygium treatment and recurrence was noted after 6
months post-operatively.
The
results show pterygium recurrence in 06 (5.0%) while 114 (95.0%) patients had
no recurrence as shown in figure 1. Stratification of age groups and gender is
shown in Table 2 and 3 respectively which show no significant difference in pterygium
recurrence with respect to age of patients and gender.
Table 2: Stratification of patients with respect to age (n=120).
|
Age (in years) |
Frequency |
Pterygium Recurrence |
P-value |
|
|
Yes n (%) |
Yes n (%) |
|||
|
20 – 30 |
23 |
00 (0.0) |
23 (100.0) |
0.582 |
|
31 – 40 |
35 |
02 (6.06) |
33 (93.94) |
|
|
41 – 50 |
38 |
03 (7.89) |
35 (92.11) |
|
|
51 – 60 |
24 |
01 (4.17) |
23 (95.83) |
|
Table 3: Stratification of gender with
respect to Pterygium recurrence.
|
Gender |
Frequency |
Pterygium Recurrence |
P-value |
|
|
Yes n (%) |
Yes n (%) |
|||
|
Male |
79 |
04 (5.06) |
75 (94.94) |
|
|
Female |
41 |
02 (4.88) |
39 (95.12) |
|
DISCUSSION
Pterygium
in the conjunctiva is characterized by elastotic degeneration of collagen
(actinic elastosis) and fibrovascular
proliferation. It has an advancing portion called the head of the pterygium,
which is connected to the main body of the pterygium by the neck. Sometimes a line of iron deposition can be
seen adjacent to the head of the pterygium called Stocker's line. The location of the line can give an indication
of the pattern of growth. The exact cause is unknown but seems to be due to
limbal stem cells damage that resist the conjunctival growth onto the cornea,
but pterygium do occur with increased exposure to wind, ultraviolet light,
or sand14.
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Figure 1: Post op pictures.
It causes chronic irritative symptoms, cosmetic complaints and
decreased vision as the pterygium encroaches the visual axis or induces
astigmatism. Indications of intervention include interference with vision,
looking bad, motility problem, recurrent inflammation and hindrance with
contact lens wear. Although the diagnosis of pterygium has been extremely easy,
it remains an unresolved disease with unsatisfactory outcomes and frequent
recurrences.15 Different options available are bare sclera excision
with or without the use of adjuncts like beta irradiation, thiotepa eye drops,
intra-operative or post operative mitomycin-C (MMC) or anti neoplastic agents,
amniotic membrane transplantation, conjunctival autograft with or without
limbus stem cells have been described16.
Despite these innovative procedures, recurrence continues to be a
complication. Reported rates of recurrence range from 2% for excision with CAG
to 89% for bare sclera excision. In recent two years, 2 surgical techniques
have become increasingly accepted as methods likely to prevent pterygium
recurrence, namely Mitomycin C application and conjunctival autograft
transplantation17. Conjunctival auto-grafting is a surgical
technique that is effective and safe procedure for pterygium removal. When the
pterygium is removed, the tissue that covers the sclera known as the
conjunctiva is also extracted. Auto-grafting replaces the bare sclera with
conjunctival tissue that is surgically removed from the temporal healthy
conjunctiva. That “self-tissue” is then transplanted to the bare sclera and is
fixated using sutures, tissue adhesive, or glue adhesive18.
It has been suggested that limbal stem cells in the conjunctiva of
the autograft may act as a barrier to conjunctival cells migration onto the
corneal surface and helps in preventing the recurrence. The limbal conjunctival
graft includes approximately 0.5 mm of the limbus and peripheral cornea. The
limbal side of the conjunctival autograft is sutured with interrupted 10/0
nylon sutures, and the conjunctival side is sutured with absorbable sutures.
The recurrence rates after limbal conjunctival autograft surgery (ranging from
0 to 15%) are almost identical to the conjunctival autograft surgery19-21,
while some authors suggest that limbal conjunctival autografts are more
effective than conjunctival autografts in preventing the recurrence of
pterygium.
This study was conducted to determine the frequency of recurrence
of pterygium with limbal stem cells autograft. The mean age of patients in our
study was 41.18 ± 11.03 years with majority of the patients i.e. 51.67% were
above 40 years of age which was very much comparable to studies
of Salagar KM et al and Rao SK et al who had a mean age of 41 and 42 years
respectively with majority of patients were above 40 years of age. Similarly,
Mejia LF et al22 in his study had found mean age of 42 years in
Pterygium patients. On the other hand, Ahmed I et al23 and Saleem MI
et al had found mean age of 55 and 60 years in their studies respectively which
is much larger compared to our study. But the mean age reported by Al-Fayez MF et
al24 was very low i.e. 33 years, compared to our study. In our
study, 79
(65.83%) were male and 41 (34.67%) were females with male to female ratio of
1.9:1. Many previous studies have also shown higher incidence of
pterygium in male than female.2,4,5,8. While Young AL et al25
has shown female predominance in his study. This male predominance in our study
is confined to the fact that men mostly work outside and are exposed to dust
and environmental hazards more than women.
Our study showed the Pterygium recurrence in 06 (5.0%) while 114
(95.0%) patients have shown no recurrence after limbal stem cell autograft
technique for pterygium treatment. This is a little lower to the results
observed by Rasool AU et al7
i.e. 10.0%. There are also many clinic based studies on limbal stem cell
autograft technique for pterygium treatment which have shown almost higher
recurrence rates to our study i.e. Kralj P et al26 reported 11.11%,
while Rao SK et al have reported lower recurrence rate i.e. 4.7% and 3.8%
respectively.
Patel D et al
and Shimazaki J et al
in their studies reported pterygium recurrence in 7.4% and 7% patients
respectively after limbal stem cell autograft technique for pterygium
treatment. Gris O et al
used a similar technique closer to the one used in our study in 7 patients with
recurrent pterygium. They reported no recurrence or significant complications.
Young AL et al12 compared mitomycin C and limbal conjunctival
autograft surgery in preventing pterygium recurrence, and they showed that the
mitomycin C patients were associated with a higher recurrence rate (15.9%) as
compared to limbal conjunctival autograft patients (1.9%). In one study (12.9%)
recurrence is seen out of 41 patients with limbal conjunctival stem cells
autograft for primary pterygia4 so prevention of pterygium
recurrence (87.1%) is significant.
In one study by Chen PP
et al13 pterygium recurrence with limbal conjunctival autografting
in primary pterygia is as high as 39% that is much higher as compared to our
study. This high recurrence rate was also found in the study by Simona et al
that reported recurrence rate of 35%. Salagar KM et al reported
recurrence in 6.38% eyes after 3-4 months post-operatively. In a prospective,
randomized study, Al-Fayez MF et al found limbal conjunctival autograft
transplantation more effective than conjunctival autograft alone in prevention
of recurrence after pterygium excision and has found no recurrence after the
limbal–conjunctival autograft.
Many other authors have shown variable recurrence rates after limbal–conjunctival
autograft transplantation for Pterygium. In a long-term study, Pulte P et al
found recurrences in 2.86% patients who underwent limbal–conjunctival autograft
transplantation. In a group of 41 cases of recurrent pterygia, Mutlu FM et al
reported a 14.6% recurrence rate with a minimum follow-up of 15 months.
DekarisI et al in his study recorded no pterygium recurrence in
90.90% patients and only 9.1% showed recurrence after follow up of 5 months. Mejia
LF et al22 has shown this rate as 1.8%.
Rasool AU et al7 in
his study found a positive association of age with recurrence of pterygium. He
concluded that youth is associated with increasing risk of recurrence and as
the person gets older, the recurrences decrease. This contradicts findings of
our study in which we have found no statistically significant difference in
Pterygium recurrence between different age groups and gender. On the whole, it
was concluded that frequency of recurrence of pterygium with limbal stem cells
autograft is very low and have no association with age and gender.
CONCLUSION
The frequency
of recurrence of pterygium with limbal stem cells autograft technique is very
low i.e. 5.0%. So, we
recommend that limbal stem cells autograft technique should be performed as a
main surgical option in every patient with pterygium for the prevention of its recurrence after surgery to reduce the
morbidity of patients.
Author’s Affiliation
Dr. Muhammad Sharjeel
Mayo Hospital Lahore
Dr. Farhan Ali
Mayo Hospital Lahore
Dr. Irfan Qayyum Malik
Associate Professor
Gujranwala Medical College
Role of
Authors
Dr. Muhammad Sharjeel
Main Author
Dr. Farhan Ali
Helped in data collection
Dr. Irfan Qayyum Malik
Helped in writing manuscript
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