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ORIGINAL ARTICLE
ARCH SOC ESP OFTALMOL 2008; 83: 479-486
COMBINED TRABECULOTOMY-TRABECULECTOMY AS
THE INITIAL SURGICAL PROCEDURE OF PRIMARY
DEVELOPMENTAL GLAUCOMA
TRABECULOTOMÍA-TRABECULECTOMÍA COMBINADA COMO
TRATAMIENTO QUIRÚRGICO INICIAL DEL GLAUCOMA
CONGÉNITO PRIMARIO
CAMPOS-MOLLO E1, MORAL-CAZALLA R1, BELMONTE-MARTÍNEZ J2
ABSTRACT
RESUMEN
Purpose: To evaluate the long-term outcome of trabeculotomy-trabeculectomy as the primary surgical
treatment for primary congenital glaucoma.
Methods: Twenty-two eyes of 14 consecutive
patients with primary congenital glaucoma who
underwent combined trabeculotomy-trabeculectomy
as the initial procedure between 1981 and 2005 were
selected for review. Records of ocular family history,
age at onset of glaucoma, symptoms and signs, corneal integrity, intraocular pressure (IOP), gonioscopy, surgery, postoperative complications, visual
acuity, refractive error, endothelial microscopy, axial
length, visual fields and final status of the optic nerve head were entered into a computer database. The
outcome, in terms of IOP obtained, was evaluated
using Kaplan-Meier survival analysis.
Results: Cumulative probabilities of success, after
performing combined trabeculotomy-trabeculectomy as the initial operative procedure, were 95.5%
after 12 months and 78.2% after 24 months, with
this rate being maintained during 15 years of followup. Four eyes (18.1%) required more than one ope-
Objetivo: Valorar los resultados quirúrgicos a largo
plazo de la trabeculotomía-trabeculectomía combinada (TTC) como tratamiento preferente del glaucoma congénito primario.
Métodos: Se seleccionaron 22 ojos de 14 pacientes
consecutivos con glaucoma congénito primario en
los que se empleó la TTC como procedimiento inicial entre 1981 y 2005. Se introdujo en una base de
datos la información relacionada con la historia
familiar, edad de inicio del glaucoma, síntomas y
signos, integridad corneal, presión intraocular
(PIO), gonioscopia, cirugía, complicaciones postoperatorias, agudeza visual, defecto de refracción,
microscopia endotelial, longitud axial, campos
visuales y estado final de la papila. El resultado de
la presión intraocular fue evaluado usando el análisis de supervivencia Kaplan-Meier.
Resultados: Las probabilidades acumuladas de éxito después de realizar una TTC como procedimiento inicial fueron del 95,5% a los 12 meses y del
78,2% a los 24 meses, manteniéndose esta proporción durante 15 años de seguimiento. Cuatro ojos
Received: July 9, 2007. Accepted: June 25, 2008.
Department of Ophthalmology. Alicante General University Hospital. Alicante. Spain.
1 Graduate in Medicine
2 PhD in Medicine
Communication presented at the 81st Congress of the Spanish Ophthalmology Society (Saragossa, 2005).
Correspondence:
E. Campos-Mollo
C/. Bañeres, 5, 4.º D
03203 Elche (Alicante)
Spain
E-mail: [email protected]
CAMPOS-MOLLO E, et al.
rative procedure because of persistent raised IOP.
Postoperative complications were rare. At the time
of the last follow-up, of 12 eyes from 8 co-operative
patients, the final best spectacle-corrected visual
acuity was 0.5 (20/40) or better, in 75% (9 eyes).
Conclusion: Combined trabeculotomy-trabeculectomy as the primary surgical procedure offers longterm high efficacy in the control of IOP without
medical treatment, is rarely associated with surgical
complications, and a low need for re-operations
(Arch Soc Esp Oftalmol 2008; 83: 479-486).
(18,1%) requirieron más de un procedimiento debido a una PIO elevada persistente. Las complicaciones postoperatorias fueron raras. Al final del seguimiento, de 12 ojos de 8 pacientes cooperadores, la
mejor agudeza visual corregida fue igual o mayor
de 0,5 en el 75% (9 ojos).
Conclusiones: La TTC como cirugía primaria ofrece una alta eficacia a largo plazo en el control de la
PIO sin tratamiento farmacológico, mostrando
mínimas complicaciones quirúrgicas y una baja
incidencia de reintervenciones.
Key words: Trabeculotomy-trabeculectomy, primary congenital glaucoma, primary developmental
glaucoma, buphthalmos, pediatric glaucoma, childhood glaucoma, glaucoma.
Palabras clave: Trabeculotomía-trabeculectomía,
glaucoma congénito primario, buftalmos, glaucoma
pediátrico, glaucoma infantil, glaucoma.
INTRODUCTION
follow-up time of 8.9 years (follow-up time was
under 5 years for all series published before).
The expression primary congenital glaucoma
(PCG) is applied only to those cases where an anatomical defect exists for the camerular angle, due to
isolated anomalies of development, which complicate the release of aqueous humour (1). This is the
most common variety of infantile glaucoma,
demanding an early diagnosis and a relatively
urgent surgical treatment, as this condition may
cause severe functional and morphological sequels.
Although goniotomy has been traditionally considered as the main option, other surgical alternatives have been proposed, such as ab externo trabeculotomy, trabeculotomy-trabeculectomy, or conventional trabeculectomy.
Combined trabeculotomy-trabeculectomy (CTT),
also called trabeculo-trabeculectomy, was described by Nicolás Belmonte for PCG in 1979 (2).
Several other authors have later published satisfactory results with this procedure (3-8).
CTT is difficult to assess in western societies,
due to its limited use, and to the low incidence of
PCG (1:10,000 newborns). In fact, the effectiveness
of this technique has been analyzed only in a handful of articles, with most studies corresponding to
arab population samples, where the incidence of
PCG is higher due to the high levels of consanguinity (1:2,500 newborns) (9).
CTT has been used during the last 25 years as the
main choice for treatment, with apparently good
initial results. A retrospective check was thus
applied to its long term effectiveness, with a mean
480
SUBJECTS, MATERIAL, AND
METHODS
A total of 22 eyes were reviewed (designated 1 to
22), from 14 consecutive patients (designated I to
XIV). All of them were diagnosed and operated on
at the Alicante University Hospital between January
1981 and December 2005. All pre surgical and post
surgical information and long term surgical results
were assessed. All operations were performed by
the same surgeon (JBM).
Since the number of alternative procedures was not
large enough to allow for statistical analysis by comparison between different techniques, patients subject
to other surgical techniques as initial treatments were
excluded. Patients were also excluded for cases where paediatric glaucomas were associated with other
ocular conditions, or systemic diseases.
A database was created including details on
family history, age of onset of glaucoma, signs and
symptoms, corneal integrity, intraocular pressure
(IOP), gonioscopy, surgery, post surgical complications, visual acuity, refractive defect, endothelial
microscopy, axial length, visual fields, final state of
the papilla, follow-up, and end result.
Pre-operative diagnosis was based upon early
signs and symptoms (photophobia, blepharospasmus, tearing, corneal edema, and increase in corneal
ARCH SOC ESP OFTALMOL 2008; 83: 479-486
Trabeculotomy-trabeculectomy in primary developmental glaucoma
size). Intraocular pressure was measured using Perkins’ flatness tonometer under halothane-induced
anaesthesia. Measurements were taken as soon as
children were ready under the effects of the anaesthetic (within the first 10 minutes after induction,
and before tracheal intubation).
Measurements of intraocular pressure (IOP)
under anaesthesia were performed 6 months after
surgery, and once a year after that. The eldest children and those who collaborated best were examined using a Goldmann tonometer.
The diagnostic criterion for surgical failure was
established when additional surgery was required,
due to intraocular pressure values above 21 mmHg
(even under topical medication) or for IOP values
above 16 mm Hg under general anaesthesia with
persisting restraints, such as symptoms (photophobia, tearing) and signs (buphthalmos, cup progression, or optic nerve atrophy). Cumulative probabilities of success were determined in accordance with
Kaplan-Meier survival analysis (SPSS v.14, SPSS
Inc., Chicago, Illinois, USA).
No complementary tests were carried out due to
the short age of some of the patients. When possible, depending on age and patient’s collaboration,
assessments were made of refractive defect, biomicroscopy, state of the optic nerve, endothelial
microscopy (SP 2000, Topcon, Tokyo, Japan), axial
length (Ocuscan, Alcon, Irvine, CA, USA), and
visual field (Humphrey, Zeiss, Dublin, CA). Up to
8 patients (12 eyes) collaborated enough to allow
for reliable examinations to be performed.
was noticed as coming from the incision, occasionally mixed with blood.
It may sometimes be difficult to detect Schlemm’s canal when an abnormal anatomical elongation of the limbus or a thinned down sclera in
buphthalmic eyes are present.
Vannas scissors are introduced at the incision
level in the exposed canal, cutting 1 mm on either
side. The double trabeculotome, right- and left
(Sourdille-Paufique, Moria®) was then inserted into
the incision, checking for obstacles to the advancement into the canal lumen. A controlled rotation
was then performed towards the anterior chamber,
thereby crossing the internal side of Schlemm’s
canal, breaking the trabecular mesh and the angle’s
embrionary tissue (fig. 2), whilst avoiding damage
to other intraocular structures. In a similar way, the
trabeculotome was then introduced through the
other end of the incision (fig. 3). The internal side
of Schlemm’s canal was finally cut in an extension
of approximately 120º.
A small portion of tissue was subsequently
extracted from the corneo-scleral bed, with an
approximate size of 1 x 2 mm, and including some
trabecular mesh and a portion of Schlemm’s canal
(trabeculectomy), followed by a peripheral iridectomy (fig. 4). The scleral tapete was then repositioned by performing 2 interrupted stitches with 10/0
nylon suture onto the corners, and then burying the
stitches. The conjunctiva was closed using interrupted or 8/0 continuous reabsorbable sutures.
Surgical Technique
The operations were started under general anaesthesia, with a superior rectus stitch with 4/0s silk
suture in order to facilitate exposure of the upper
conjunctiva. A fornix-based conjunctival flap was
then created onto the upper limbus (at I or at XI). A
rectangular tapete was hen dissecated towards the
limb with an approximate size of 2 x 3 mm, into
half or two thirds of the scleral thickness.
Using a high magnification, a radial incision was
performed on the underlying sclera, using the blunt
end of a slit knife (Fig. 1). The incision was carried
out on the transition area between the ‘blue’ cornea
(trabecular band) and the scleral tissue where Schlemm’s canal was theoretically located. The canal
was identified when a reflux of aqueous humour
Fig. 1: A radial incision is carefully performed using a
knife on the transition area between the ‘blue’ cornea
(trabecular band) and the scleral tissue, in order to identify Schlemm canal.
ARCH SOC ESP OFTALMOL 2008; 83: 479-486
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CAMPOS-MOLLO E, et al.
Fig. 2: The trabeculotome is introduced onto Schlemm’s
canal. Controlled rotation is then applied towards the
anterior chamber, thus breaking the trabecular mesh.
Antibiotics and corticoids were applied after surgery. Eyes were occluded for unilateral cases, and
omitted for bilateral occurrences. Post surgical treatment was dispensed for three to four weeks, reducing prescription in accordance with clinical appearance and evolution.
RESULTS
22 eyes were analyzed for 14 patients, 10 males
(71.4%) and 4 females (28.5%). The disease was
bilateral in 8 children (57.1%) and unilateral in 6
(42.8%). A family history of PCG was present for
Fig. 3: The trabeculotome is then introduced at the
other end of the incision and rotated.
482
Fig. 4: At a later stage trabeculectomy is performed,
followed by a peripheral iridectomy.
only one case. In unilateral cases the right eye was
involved in 66.6% of cases, with the left eye compromised in the other third.
Age at the time of diagnosis varied between 1
day and 23.5 months (mean value 2.3 months). Suspicion of congenital glaucoma was based on increased corneal size (22 eyes; 100%), corneal edema
(14 eyes; 63.6%), tearing (12 eyes; 54.5%), photophobia and blepharospasmus (13 eyes; 59%). The
mean horizontal corneal diameter measured was
13.4 ± 1.1 mm (range from 12 to 15 mm). Mean
values for pre surgical IOP before first surgery was
20.1 ± 4.2 mm Hg. Follow-up time extended from 1
to 24 years, with a mean value of 8.9 years (118.8
months). Nystagmus by fixation was seen for one of
the children.
The cumulative probability of success for IOP
with one procedure only was 95.5% at 12 months,
and 78.2% at 24. This proportion was constant
during the 15 year follow-up. However, only 5
patients (8 eyes) reached 10 years of follow-up.
Most surgical failures ocurred during the first two
years (fig. 5).
Four eyes (18.1%) required more than one operation due to high IOP values, despite the topical
hypotensive treatment applied. The surgical technique selected for all re-operations was trabeculectomy. After a second operation IOP went back to
normal levels in 2 eyes. One of these needed additional topical betablockers. On the 2 eyes remaining
for the same patient (patient I) ocular tension was
ARCH SOC ESP OFTALMOL 2008; 83: 479-486
Trabeculotomy-trabeculectomy in primary developmental glaucoma
Fig. 5: The Kaplan-Meier survival curve shows assessment of success for IOP control after the first procedure
for primary congenital glaucoma. The number of eyes
(n) with a risk to fail at different intervals is shown at the
horizontal axis.
not controlled. A third operation was performed at
another hospital. One of them evolved into a ptisis
bulbi, whilst the other was affected by severe trauma with exophthalmos and retinal detachment, leading to eye evisceration.
A non-significant bleeding was usually noticed at
the anterior chamber during surgery, when opening
Schlemm’s canal. A moderate hyphema involved 2
eyes only, which was resolved with no consequences within a few days.
An iris entrapment involved 3 eyes at the time of
incision. An uveal ectropion was associated to this
for one eye, with no consequences. Another eye
required a synechiotomy, whilst the third eye showed corectopia, needing synechiolysis and plastic
surgery for the papilla. An anterior peripheral subcapsular cataract affected the third eye ten years
later, but no surgery was required due to the very
limited consequences on patient’s vision.
A lens subluxation was detected for one eye four
years after the procedure, requiring extracapsular
extraction and a posterior chamber IOL implant.
The posterior capsule was then opacified through a
capsulotomy with a YAG laser. A proliferative
vitreoretinopathy developed later for this eye, and
surgery was performed, with poor functional
results. The eye was then involved in an accidental
trauma with corneal laceration and hyphema, which
was resolved spontaneously within a few days, with
ocular pressure under control, but with total loss of
vision.
Only 3/22 eyes (10.9%) showed severe complications with an unfavourable final evolution, with
two of those eyes for the same patient.
Mean IOP in the last measurement under general
anaesthesia was 10.89 ± 4.1 mm Hg, with a mean
reduction of 10.82 ± 4.36 mm Hg. IOP was under
control for 20 eyes (90,9%) at the end of follow-up,
after one or two interventions, with only one eye
requiring additional topical hypotensive treatment.
All blisters were either diffuse or slightly elevated
for all eyes with IOP under control.
No variations were noticed for the horizontal diameter of the corneas (mean 13.4 ± 1.3 mm), as compared with pre surgical measurements. A transparent cornea was noticed at the end of follow-up for
13 eyes (59.05%), with 5 eyes (22.7%) presenting a
mild corneal opacity, with acceptable transparency,
and 2 eyes (9.09%) showing a persistent diffuse
opacity. The two corneas of patient I (9.09%) mentioned above could not be assessed, for obvious reasons.
Criteria were met by the eyes of 8 collaborating
patients for studying visual acuity, biomicroscopy,
IOP (as measured with Goldmann tonometer),
endothelial microscopy, axial length, and campimetry. Patient I was excluded from the analysis,
despite his willingness to collaborate. Table I below
shows a summary of the exploration results.
The best visual acuity with correction was equal
or better than 0.5 for 9 eyes (75.0 %), and under 0.1
for 2 eyes (16.6%). Loss of vision was attributed
mainly to corneal opacity or amblyopia. Ophthalmoscopy showed an increase in papillary excavation for 2 eyes. Reliable campimetric data was
obtained for 4 eyes only, for which no significant
campimetric alterations were visible.
DISCUSSION
Surgery is the only effective treatment for PCG.
Goniotomy ab interno is the main choice for a
majority of surgeons, when corneas are transparent
enough to allow for adequate visualization of the
camerular angle (10-13). On the other hand, Sch-
ARCH SOC ESP OFTALMOL 2008; 83: 479-486
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CAMPOS-MOLLO E, et al.
Table I. Long term results for PCG patients who collaborated to obtain sufficiently reliable examinations
E/P
3/II
4/II
5/III
6/III
7/IV
8/IV
9/V
10/V
11/VI
12/VII
13/VIII
14/IX
Age (years)
VAc
IOP ‡
Cornea
PE
CD
AL
VF
17
17
16
16
12
12
12
12
11
6
5
5
1
1
1
0.7
0.8
0.8
0.3 *
LP *
0.5
0.9
0.05 †
0.5
13
12
14
17
17
18
15 §
14
10
14
20
16
T
T
MCO
MCO
MCO
MCO
T
SCO
T
T
MCO
T
2/10
2/10
3/10
4/10
3/10
7/10
NF
NF
2/10
2/10
3/10
2/10
3,228
2,694
1,784
1,509
1,645
1,940
1,421
NF
3,187
2,476
NF
NF
24.02
24.08
23.68
25.17
26.23
27.14
23.92
24.12
23
24.85
24.61
NF
N
N
N
N
NPA
NPA
NPA
NF
NPA
NF
NF
NF
E/P=Eye/Patient; Vac=Visual Acuity (corrected);LP=Light Perception; PE=Papillary Excavation; CED=Corneal Endothelial Density (cells/mm2);
AL=Axial Length (mm); VF=Visual Field; T=Transparent; MCO=Mild Corneal Opacity; SCO=Stromal Corneal Opacity; NF=Not Feasible;
NPA=No Possible Assessment; N=Normal. *Eye affected by intense photophobia, despite IOP under control. † Amblyopia due to lack of collaboration from the family. ‡ Post surgical IOP measured with Goldmann tonometer (mm Hg). § IOP under control with topical medication.
lemm’s canal is not sectioned during goniotomy,
and no actions are performed involving certain histopathological alterations described for PCG, such
as immaturity of the trabecular mesh or Schlemm’s
canal (1,14,15). This could explain surgical failures
in some cases, and the need for a second procedure.
CTT creates two exit ways for aqueous humour:
the first path (trabeculotomy) sections the total
thickness of the trabecular mesh, thus communicating the anterior chamber and Schlemm’s canal,
whilst the second exit way (trabeculectomy) allows
for the creation of a supplementary fistula for drainage between the anterior chamber and the subconjunctival space (5,7). This double exit path would
account (at least partially) for the high success rates
in IOP control with a single procedure (4,5).
Furthermore, CTT offers a significant advantage
for those cases where visualization of the angle is
constrained by corneal opacity (63.6% in our
series), by acting on an area well under control for
the anterior segment surgeon using the microscope.
The main drawbacks for this technique, however,
include the technical difficulties related to dissecating a lamellar scleral flap in eyes heavily thinned
out by buphthlamos, accurately locating and identifying Schlemm’s canal in order to introduce the trabeculotome in cases of extreme megalocornea, where the limbic area is heavily altered, and a ‘blind’
rupture is produced of Schlemm’s canal and the trabecular tissue, since no direct view of the angle is
possible (as opposed to goniotomy). In any case,
supplementary trabeculectomy provides an additio-
484
nal exit way for aqueous humour even when Schlemm’s canal or its canalización with the trabeculotome are not accurately performed, so that IOP may
decrease by filtration. Finally, areas for possible
future surgery in case of surgical failure are limited,
due to involvement of the perilimbic conjunctiva.
The authors decided to select CTT as their main
choice for opaque and transparent corneas due to its
comprehensive microscopic control, familiarity
with the surgical area, the good results obtained
from the start with a single procedure, and the small
proportion of complications.
The positive outcome of this analysis is supported
mainly by excellent long-term surgical results (8.9
years on average), a low rate of new surgical interventions, good control of IOP, reduced signs and
symptoms, and functional visual recovery. These
results are all similar to those obtained in other studies, even with a much shorter follow-up period (3-8).
Complications for CTT are in practical terms not
different from those recorded for each of the methods
applied separately (7). Mild hyphema was specially
prevalent, with no atalamia, or problems derived from
the filtration blister (infection, thinned out blisters,
perforation, etc.). Iris enclavamiento at the level of the
trabeculectomy was significant for one eye only.
Most surgical failures occurred within the first
two years, and new standard trabeculectomies were
scheduled as a second procedure. The underlying
nature of the disease and an early diagnosis have a
strong influence on the evolution and the prognosis
of all cases (16). The unfavourable final results for
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Trabeculotomy-trabeculectomy in primary developmental glaucoma
three eyes (two for one patient alone) were possibly
related to the nature of the malformation, and to a
larger dilation in the primary surgical treatment. On
the other hand, it seems clear that keeping IOP under
control for these eyes was not enough to ensure
good functional results. Attention must be paid to
each patient individually, treating anisometropia or
the likely amblyopia with an early optical correction, or eventually through occlussion exercises.
The retrospective design and the small number of
patients were two of the limitations of the current
study, which prevented the authors from reaching
final conclusions derived from the information available. However, in our opinion, CTT is safe, effective, and predictable enough for it to be selected as
the primary surgical treatment for PCG, at least
when conventional goniotomy is either not properly
mastered or it may become the source of additional
problems.
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