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NR 1-3/2008
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SICS – a cost
effective alternative to phacoemulsification for developing
countries in Nepal
Chirurgia małego cięcia (SICS)
jako niskobudżetowa alternatywa dla fakoemulsyfikacji w
rozwijających się krajach – na przykładzie z Nepalu
Rafał Nowak
From Eye Departament, City Hospital, ZOZ Poznań-Nowe Miasto,
Medical Director: Józef Szczypiński, MD |
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| Summary: |
Millions of people
worldwide are blind from mature cataracts. The
developing countries cannot afford expensive modern
technologies to treat these cases. A cost effective,
fast, machine independent procedure is necessary. The
purpose of this study is to describe such a technique,
little known in Poland – manual small incision cataract
surgery (SICS), where the whole nucleus is removed
through a self-sealing sclero-corneal tunnel. Within the
last several years SICS has become the main way of
cataract removal in underserved populations of Asia,
with Nepal as an example. Thus, the developing countries
have developed a cost effective alternative to
phacoemulsification with a very good clinical outcome. |
| Słowa kluczowe: |
chirurgia zaćmy, SICS,
chirurgia małego cięcia, bezszwowe zewnątrztorebkowe
usunięcie zaćmy, technika fish-hook. |
| Key words: |
cataract surgery, SICS,
small incision cataract surgery, sutureless
extracapsular cataract extraction, fish-hook technique. |
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Introduction
Despite all that modern technology has done to advance treatment
of cataracts, our greatest challenge continues to be the large
and increasing backlog of cataract blindness in developing
countries. While in North America and Europe research and
development have been directed primarily at new intraocular lens
and phacoemulsification technology, millions with reversible
blindness caused by cataracts go untreated in Asia and Africa
(1,2).
Although the word trend is directed towards phaco surgery a bulk
of cataracts in developing countries are operated by other
procedures like SICS (small incision cataract surgery, manual
small incision cataract surgery, sutureless surgery, sutureless
extracapsular cataract extraction, manual phaco) and the
old-aged standard ECCE (3,4). The reason why the poorer part of
the world does not utilize the latest machine-dependant
techniques is very simple. Modern phacoemulsification devices
are very expensive to purchase and maintain, have relatively
high disposable costs (foldable IOLs, injectors etc.) and
require extensive surgical training. Furthermore, for the more
advanced and mature cataracts, typical for underserved
populations, performing phacoemulsification becomes more
difficult and complication prone (1,2,5,6).
In Nepal phacoemulsification as well as sutured ECCE are
practiced rarely. Most of cataracts are operated with the manual
SICS procedure, where the whole nucleus is removed through a
self-sealing sclero-corneal tunnel. It induces a small amount of
astigmatism, quick rehabilitation, requires no stitches and is
cost effective (4,5,7,8). Sanduk Ruit and associates have
recently reported that the clinical outcome of SICS and
phacoemulsification is comparable (1). This fact can be also
confirmed by my own experience of several months spent in
Nepalese hospitals.
Nepal has two schools of sutureless surgery: Lahan Eye Hospital
and Tilganga Eye Center. The first one, located in Lahan (south-eastern
part of the country) is run by Albrecht Henning. In 1997 he
created his own modification of SICS. Its core is the fish-hook
technique. Within 5,5 years (1997-2003) more than 170 000
cataracts were operated with this method (4). Currently the
annual number of sutureless surgeries at Lahan Eye Hospital is
up to 50 000.
In Kathmandu, there is another significant example of the
efficient eye care system – Tilganga Eye Center. Its founder,
Sanduk Ruit also has developed his own variation of SICS. Thus,
most of eye surgeons in Nepal practice the above mentioned
methods. However, those trained in India use another one,
designed by Michael Blumenthal.
Techniques
Lahan method (the Fish-hook technique)
Before surgery an ophthalmic assistant performs a
retrobulbar or peribulbar block (in some parts of Nepal it is
combined with a facial block – O’Brien’s method) outside
operating theater. Next, orbital compression with a metal
compressor (345g) is done for 10 minutes (Picture 1, Picture 2).
Then the patient walks into the operating theater. A trained
assistant makes the eye ready for surgery by placing the
superior rectus suture, preparing a fornix based conjunctival
flap at 12 o’clock position and cauterizing scleral blood
vessels. It happens so in the superior approach. If the surgeon
chooses the temporal one, the operating field is prepared at the
lateral side of the eye.
A central frown 6-8 mm incision is made 2 mm behind the limbus (Figure
1).
A partial thickness (1/2) scleral tunnel is dissected 2 mm into
the clear cornea with a crescent knife. A side port paracentesis
can be made to facilitate intraocular manipulation (optional).
The anterior chamber is entered with a keratome and the internal
lip of the incision is extended only to one side. Then,
viscoelastic is injected into the anterior chamber. Again, the
other side of the internal lip is extended with a keratome. The
keratome stays in the anterior chamber and makes the envelope
capsulotomy – a horizontal linear incision in the anterior
capsule (Figure 1). After hydrodissection the nucleus is
mobilized within the capsular bag. Viscoelastic material is
injected between the posterior capsule and the nucleus as well
as into the anterior chamber. The fish-hook (a 30 gauge needle
with a bent tip) (Picture 3) is inserted between the nucleus and
the posterior capsule with the sharp tip horizontal. Then the
tip is turned upwards. As the hook is being withdrawn it engages
the nucleus and delivers it from the eye (Figure 2, Picture 4).
The residual cortex is removed from within the bag with a Simcoe
cannula. Here the surgeon is aspirating with a 5 ml syringe in
his left hand and is infusing fluid into the anterior chamber
through the cannula held in his right hand. Again viscoelastic
substance is injected into the anterior chamber as well as into
the bag. An intraocular lens is inserted directly into the bag
and dialed if needed with a Sinskey hook under the still
existing anterior capsular flap. A side incision in the anterior
capsule is made and the flap is removed with a forceps or a
Simcoe cannula (Figure 3). Viscoelastic material is washed out.
As the last tool is withdrawn from the anterior chamber the
sclero-corneal tunnel seals itself. The conjunctiva over the
external wound is neither sutured nor cauterized.
Tilganga method
Only differences in comparison to the above mentioned method
will be mentioned below.
The groove behind the limbus is linear (straight) (Figure 4),
The sclero-corneal tunnel is extended 2-3 mm into the clear
cornea. At this point the anterior chamber is entered through
the tunnel with a 27 – gauge needle attached to a syringe
containing Ringer’s fluid. Its bevel is used like a knife to
make 2 incisions with fine chopping motions in the anterior
capsule. Thus, a triangular flap of the still remaining anterior
capsule is created. The apex of the capsulotomy is stripped
inferiorly with the tip of the needle.
After the anterior chamber is entered with a keratome,
hydrodissection and nucleus delivery into the anterior chamber
is carried out with a Simcoe cannula. Then the nucleus is
extracted with a corrugated irrigating toothed nuclear extractor.
After removing cortex debris, the anterior chamber is filled
with air and an IOL is implanted into the capsular bag. The
capsular flap is removed with a Simcoe cannula. The conjunctiva
over the external wound is closed with cauterization at both
edges.
Blumenthal’s method (the Mini – Nuc technique)
At the beginning a capsulorhexis is made through a side
paracentesis with a cystotome. The initial scleral groove has a
different shape and is started 1 mm behind the limbus (Figure
5). The sclero-corneal tunnel penetrates 2 mm into the clear
cornea. The nucleus is usually extracted with an irrigating
vectis (M. Blumenthal recommends using a glide as well as
anterior chamber maintainer) (8)
Postoperative treatment
Within the first 2 postoperative days patients are administered
frequent antibiotic-steroid eye drops (Table I). They are
usually discharged on the second postoperative day and advised
to use the medicine 4 times daily for one month on.
Discussion
Complications
Table II shows possible complications after small incision
cataract surgery.
Parikshit Gogate (9) has confronted the complications of SICS
and sutured ECCE. The study shows that the rates of
intraoperative and postoperative complications were similar in
the two groups, except for the transient postoperative corneal
oedema, which was more common following SICS. However, in his
research, during SICS the nucleus was delivered into the
anterior chamber before its removal (9). It seems likely, that
it might have been the cause of more frequent corneal oedema
after surgery. Another study tends to confirm this hypothesis
(5). Albrecht Henning reports corneal oedema as a minor problem
in his analysis of 500 cases of SICS operated with the fish-hook
technique. Here, the nucleus is extracted directly from the
capsule, which reduces the endothelial damage significantly.
It is possible, that in procedures like the one from Tilgange
Eye Center, where the IOL is implanted under air, there may be a
higher probability of the endothelial damage. Therefore, it is
recommended that the viscoelastic should be used.
Another complication – hyphaema is likely to occur within the
postoperative period (1,5). It is the result of the wide
sclero-corneal tunnel. Hence, it happens less often in
techniques where the clear cornea incision is made. Sanduk Ruit
(1) has compared phacoemulsification and SICS. 54 parients have
been operated with each procedure (totally 108). Intra and
postoperative complications were rare in both groups. In the
phacoemulsification group there was one instance of posterior
capsule rupture and none in the SICS group. There was one minor
hyphaema caused by phacoemulsification and 16 by SICS. None of
them required intervention, and all of them cleared
spontaneously by the 5th postoperative day. No other significant
complications were observed in the operative and postoperative
period.
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SICS – the learning curve
There is no doubt that sutureless cataract surgery is more
difficult to learn than sutured ECCE. A self-sealing wound
requires a very accurate tunnel construction as well as good
surgical skills and experience to work inside the eye through a
narrow tunnel (4). Lahan Eye Hospital has suggested the
evaluation criteria for surgeons willing to learn SICS. The
surgeon may be suitable if after at least 100 consecutive
sutured ECCE the complications, especially posterior capsule
rupture, are less than 5% and the number of patients with
postoperative uncorrected visual acuity of less than 6/60
remains below 5% (4).
Surgically induced astigmatism
The surgically induced astigmatism (SIA) differs depending
on the approach chosen by the surgeon. The superior approach
makes about 1,4 D and the temporal approach creates around 0,4D
(5,6). However, the Tilganga sources suggest higher levels of
astigmatism – 1,7 D for the superior approach and 0,75 D for the
temporal approach. Another study reports astigmatism of 0,88 D
in the tempotal approach that makes it comparable with
phacoemulsification (1). In general, the width of the tunnel as
well as the distance of its external entry from the limbus
influence the SIA.
Fast visual recovery
In comparison with sutured ECCE, sutureless surgery provides
fast visual recovery (5). The self-sealing incision and no
suture-related problems are two most important factors helping
achieve that goal. Moreover, the Lahan method, which I
personally recommend, provides even better results in terms of
the postoperative condition of the cornea. The envelope
capsulotomy and the fish-hook technique facilitate nucleus
removal directly from the bag leaving the anterior capsule
intact. It minimizes the risk of nucleus-endothelial touch which
has a crucial impact on postoperative visual recovery (4,10,11).
Fast visual recovery seems to be the advantage of not only
phacoemulsification but also SICS (1).
Time of surgery
Thanks to the fact that no sutures are required time of
surgery may be reduced to minimum in the hands of an experienced
surgeon. Different sdudies show that the average time of surgery
can reach even 3,75 min per case (2,12). Another study indicates
the average duration of SICS at the level of 4 min.(5) Geoffrey
Tabin has been able to perform more than 150 cases in one 9-hour
stretch, which makes an average of 17 cases per hour and gives
the average time of surgery of 3,6 min (1).
Costs
The cost of consumables per cataract operation, including an IOL,
all medicines used before, during and after surgery, anesthesia,
viscoelastic, irrigating solutions, disinfectants and eye pads
can be reduced to 6.50 USD (5). In Kathmandu, Nepal, within the
Tilganga Eye Center there is a local IOL factory. It is called
the Fred Hollows Intraocular Lens Laboratory and produces high
quality PMMA as well as foldable lenses under an Australian
license. The commercial cost of one PMMA lens is 6 USD, one
foldable lens with an injector is sold for 30 USD. The factory
use lower rates for Nepalese hospitals. It holds ISO
certificates guaranteeing high quality production standards (ISO
9001:2000, ISO 13485:2003, CE Mark – certified by SGS, UK).
Conclusios
Sutureless surgery appears to be a good alternative for
phacoemulsification and an excellent solution for developing
countries. It proves that high quality cataract surgery can be
achieved at low cost on a large scale. It combines the
advantages of expensive, modern, machine dependant procedures
like phacoemulsification (low astigmatism, fast visual recovery,
short rehabilitation) with cost effectiveness. There are studies
(1) in which clinical results of both techniques are comparable
– undeniably this subject needs more research. SICS is more
difficult to learn than standard sutured ECCE and requires
additional skills. However, the extensive and expensive surgical
training necessary for phacoemulsification is hardly possible in
countries where the majority of people suffers from poverty.
Furthermore, the brunescent, hard cataracts typical for
underserved populations make phacoemulsification more difficult,
time consuming and prone to complications (1). For these reasons,
manual small incision cataract surgery can be the answer to high
needs for cataract surgery in the developing countries.
Acknowledgments: The author directs special thanks to Dr. Yanta
Mani Prathan, Dr. Sudhir Gautam and Mr. Homan Nepali from Lions
Eye Care Center, Kathmandu, Nepal.
References:
1. Ruit S, Tabin G, Chang D, Bajracharya L, Kline DC,
Richheimer W, Shrestha M, Paudyal G: A prospective randomized
clinical trial of phacoemulsification vs manual sutureless small
incision extracapsular cataract surgery in Nepal. American J
Ophtalmol, 2007, 143, 1, 32-38.e2
2. Chang DF: Taking the greatest challenge in cataract surgery.
British J Ophthalmol 2005, 89, 1073-1077.
3. Sood A, Thakur SK, Kumar S, Badhu B: Keratometric astigmatism
after ECCE in eastern Nepal. Continuous versus interrupted
sutures. Indian J Ophthtalmol 2003, 51, 53-57.
4. Hening A: Sutureless Non-phaco Cataract Surgery: A Solution
to Reduce Worldwide Cataract Blindness? Community Eye Health
2003, Vol. 16, 48, 49-51.
5. Hening A, Kumar J, Yorston D, Foster A: Sutureless cataract
surgery with nucleus extraction: Outcome of a prospective study
in Nepal. British J Ophthalmol 2003, 87, 266-270.
6. Gokhale NS, Sawhney S: Reduction in astigmatism in manual
small incision cataract surgery through change of incision site.
Indian J Ophthalmol 2005, 53, 201-203.
7. Thomas R, Kuriakose T, George R: Towards acheving
small-incision cataract surgery 99.8% of the time. Indian J
Ophthalmol 2000, 48, 145-151.
8. Blumenthal M, Kansas P: Small Incision Manual Cataract
Surgery. Jaypee 2005, VIII, 64-65, 31-32, New Delhi.
9. Gogate P: Community Eye Health 2003, Vol. 16, 18, 54-55.
10. Kałużny J: Implantation of an artificial lens into the
capsular bag by the envelope method. Klinika Oczna 1988, 90,
502-503.
11. Szweda E: Evaluation of 200 extracapsular cataract
extractions with the use of an envelope technique. Klinika Oczna
1997, 99, 379-382.
12. Venkatesh R, Muralikrishnan R, Civerchia Balent L, Karthik
Prakash S, Venkatesh Prajna N: Outcomes of high volume cataract
surgeries in a developing country. British J Ophthalmol 2005,
89, 1079-1083.Praca wpłynęła 25.06.2007 r.
(983)
Zakwalifikowano do druku 12.12.2007 r.
Reprint requests to:
Rafał Nowak
Oddział Okulistyczny, Szpital ZOZ Poznań- Nowe Miasto
ul. Szwajcarska 3
61-285 Poznań,
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