Download Anopthalmia

Congenital Anophthalmia
Classification
1. Syndromic
2. Non-syndromic
Evisceration is the removal of the contents of the globe while leaving the sclera and
extraocular muscles intact.
Enucleation is the removal of the eye from the orbit while preserving all other
orbital structures.
Exenteration is the most radical of the three procedures and involves removal of the
eye, adnexa, and part of the bony orbit.
Incidence
 M=F
 1 in 50,000 births
 True anophthalmos
i. complete absence of the globe through failure of formation of the optic
vesicle, and it is an extremely rare condition.
 Micropthalmos
i. Unilateral in 75%
ii. presents most often as an isolated finding or within the spectrum of
otomandibular dysostosis.
Embryology
 developmental-field defect located in Pfeifer’s diacephalic region
 defined as the (bilateral) border zone between the frontonasal and the
posterolateral regions of the face and stretches from the temple, crossing the orbit
and the lateral parts of the nose, including the ala nasi, running along the philtral
column of the upper lip, and ending between the premaxilla and the posterolateral
part of the palate and the upper jaw at the nasopalatine duct
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types of craniofacial malformations that occur here include isolated clefts of the
lip (alveolus and palate) or of the nose, most of the Tessier-type clefts (numbers 2,
3, 4, 8, 9, 10, 11, and 12), as well as cryptophthalmia, microphthalmia, and
anophthalmia.
Thus, microphthalmia and anophthalmia also may be found in conjunction with
hypertelorism (a malformation of the frontonasal region) or with hemifacial
microsomia (a disorder of the posterolateral region).
At the time of birth normal globes are said to have a volume of 2.5 ml.
eye and the orbit grow the fastest during the first year of life.
70% of the increase of the globe’s volume occurs by 4 years of age and 90 percent
by age 7.
While growth of the eye ends at age 14, the growth of the orbit ends at age 11 in
females and at age 15 in males
This is why enlarging the orbit in the first years of life should be attempted
It is known that the developing eye, being part of the “functional matrix,” has a
marked effect on orbital growth.
Considerations
 globe plays a role of essential importance in orbital growth, and its diminished
contribution in the congenitally anophthalmic orbit causes:
1. microorbitism
2. conjunctival sac atresia
3. short, phimotic lids (microblepharism)
 In severe microphthalmos, the eye is grossly hypoplastic and blind.
 Unilateral clinical anophthalmia always results in hypoplasia of the ipsilateral
bony orbit, as there is no stimulus inducing growth of the orbital socket.
 This, in turn, leads to facial asymmetry with hypoplasia of the ipsilateral midface,
a canted occlusal plane, and a short ascending ramus of the mandible.
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In contrast, bilateral anophthalmia may lead to symmetrical microsomia of the
midface as a whole
Management
 Formerly, microphthalmia and anophthalmia were treated by osteotomy of the
bony orbit followed by lengthening of the lashbearing lid and grafting of mucosa
to the socket
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Early management consists of eviscerated (removal of its contents, preserving the
sclera with its extraocular muscle attachments and Tenon’s capsule) or enucleated
(removal of the globe, preserving Tenon’s capsule) and replaced by a spherical
implant
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Asscess is usually through combined bicoronal and lid incisions
Methods
1. Serial expansion with fixed sized expanders
 implant serves as a support for the eyelids and conjunctival sac anteriorly
and maintains the volume of the orbit. Exchanged every 6 months for larger
prostheses
 In a second stage, a removable ocular prosthesis that mimics the eye is fitted
to the contours of the conjunctival sac
2. dermis fat grafts
 idea was that this would grow and exert some pressure onto the bony walls
of the orbit.
3. expansion osteotomy
 three wall orbital expansion (Tessier)
 lateral wall osteotomy and temporalis transfer for bulk and vascularised bed
to support SSG (Lee PRS 1999)
 temporalis may be lengthened by taking Periosteum
 temporal defect filled with hydroxyapatite
4. osteotomy and tissue expander
 several shortcomings: decrease of interorbital distance and a high percentage
of extrusions of these expanders.
5. hydrophilic (self-inflating) expanders
 copolymer of methylmethacrylate andN-vinylpyrrolidon
 PRS Oct 2005 – reported that palpebral fissure lengthened, the conjunctival
sac expanded and the bony orbit stimulated to grow by these expanders
Technique of Evisceration
 can be performed with or without a keratectomy, although it is preferable to
preserve the cornea if possible
 a stab incision is made at the 12 O'clock position, 5-mm posterior to the limbus.
The wound is then opened to the right and left for 180° and the intraocular
contents are delivered with an evisceration spoon
 The endothelium is removed and neurosurgical peanuts are used to remove as
much pigment as possible from within the scleral envelope. Any remaining
pigment is removed by scrubbing with cotton-tipped applicators soaked in 95%
alcohol, with care taken to avoid conjunctival inflammation from contact with the
alcohol. Irrigation with suction is then performed to remove the residual pigment
and alcohol
 The scleral envelope is sized and a hydroxyapatite implant, soaked in antibiotic
solution is inserted
Technique of Enucleation
 levator muscle is isolated by passing a 4-0 silk, double-armed suture full-thickness
through the upper fornix, in a mattress fashion. This will protect the muscle and
permit easy identification of the superior fornix during closure of anterior Tenon's
capsule, thereby avoiding foreshortening of the fornix.
 A 360° peritomy is then performed, with care taken to preserve as much of the
conjunctiva and Tenon's capsule as possible. The extraocular muscles are then
tagged with 5-0 Vicryl sutures and are released by resection at their attachments to
the globe. A neurectomy is then performed, according to the surgeon's preference,
and the globe is delivered. Care should be taken to maintain hemostasis until the
implant is placed in the orbit.
 Traditionally, the ocular implant was placed within Tenon's capsule, as first
described by Frost, necessitating the use of a smaller implant.
 However, due to the enophthalmos associated with these smaller implants, Soll
recommended placement of the implant deeper within the muscle cone, posterior
to Tenon's capsule. This posterior placement necessitates the use of a larger
implant. As a variation of Soll's technique, the implant should be placed within
Tenon's capsule without closure of posterior Tenon's capsule. The rent in posterior
Tenon's capsule, where the optic nerve penetrated, should be inspected; it will
vary depending on how close to globe the nerve was cut. If necessary, enlarge the
rent using a blunt hemostat. This will allow some portion of the implant to extend
into the muscle cone, thereby alleviating pressure on the closure and the tissues
overlying the implant.
Technique of Exenteration
 Eyelid sparing techniques, retention of conjunctiva, and preservation of the
periorbita are methods that have been introduced as modifications of exenteration
to aid in facial rehabilitation.
 Complications include CSF leak, sino-orbital fistula
 Options for coverage include
1. spontaneous granulation (high rate of fistulas)
2. grafts
o dermal graft
o dermis fat graft
o split skin graft.
3. pedicled flaps
o temporalis muscle transposition
o temporoparietal fascial flap
o midline forehead flaps
o frontal island flap (PRS May 1998)
o cheek flaps
o retroauricular island flap (Guyuron PRS 1985)
4. Free flap
o Dorsalis pedis used for eyelids
Technique of Serial Expansion (PRS Sept 2001)
Stage 1
1. Volume expansion
a. Plan the orbit to be shallower than normal – allows implant to sit better
b. frame of the orbit, however, should mirror the healthy side, such that the
brows and medial and lateral canthi lie symmetrically opposed.
c. The only exception is the inferior orbital rim, which benefits from being
fashioned more superiorly to provide a shelf of bony support for the implant.
d. Spherical implants of fixed diameter are a time-tested, effective method for
stimulating bony orbital growth
e. Silicone or methymethacrylate implants preferred
f. Method:
i. expansion is started early (within weeks of birth)
ii. upsized every 6 months
iii. implant is wrapped in an autograft of fascia lata, temporalis fascia, or
pericranium that is closed with a pursestring suture and placed within, or
immediately posterior to, Tenon’s capsule.
iv. Conjunctival layer is closed without tension over the implant, which
itself is chosen to be as large as possible (16 to 20 mm in diameter) when
placed during the period of orbital growth.
g. Supplementing the volume of a micro-orbit is primarily achieved with
transposition of the temporalis muscle and the use of cranial bone grafts.
i. anterior two-fifths of the temporalis muscle are used to line the orbit
through a window osteotomy made in the lateral orbital wall
ii. posterior three-fifths are then transposed anteriorly to prevent an
unattractive hollow in the temporal region.
2. Orbital contour
a. Autogenous bone grafts – to correct volume defects (intraorbital placement),
to support the implant (orbital floor placement), or to bolster the stock of
deficient orbital rims (lateral, superior, or inferior orbital rim or lateral wall
placement).
3. Conjuctival sac
a. Despite serial static expansions, grafts are often required to create fornices
of sufficient depth, and a choice exists between buccal mucosa and skin.
b. Transposition of temporalis may be required to enlarge the sac
4. Eyelids
a. Problems include: short and stiff eyelids, a narrow palpebral fissure, canthal
dystopia, and eyelash deficiencies
b. Serial conformers will expand the lids
c. Surgical maneuvers to widen the palpebral fissure should be discouraged
unless absolutely necessary, because they scar the lids
5. Facial harmony
a. Rhinoplasty delayed until teenager
b. Microtia, orthognathics, soft tissue augmentation
Method for hydrophilic expansion (PRS Oct 2005): Rostock Treatment Protocol
1. At approximately 3 months of age, expansion of the conjunctival sac was started by
implantation of an osmotic expander of hemispheric shape with a final volume of 0.9
ml and a final diameter of 14 mm (radius 7 mm).
2. Approximately 2 months later, this was exchanged for either a conformer made of a
glass ball (10 mm in diameter) or an artificial eye (in the form of a glass shell) for
another 3 months to produce a smooth, nonirritated mucosal layer of the enlarged
conjunctival sac.
3. At approximately 9 months of age, (approximately 5 to 6 months after the first
surgical intervention), the bony orbit was further expanded starting with implantation
of the first ball-shaped osmotic expander into the soft tissue of the orbit, with a final
volume of 2.0 ml (diameter 15 mm). In addition, a glass shell eye prosthesis with a
central hole was brought into the conjunctival sac.
4. Whenever clinical impression dictated (i.e. reduced prominence of palpebral
apparatus or hollow-eye appearance), the 2-ml, ball-shaped expander was exchanged
for a 3-ml (final volume) expander, in addition to the artificial eye in the conjunctival
sac. The next steps were 4-ml and 5-ml expanders respectively.
6. The last step was exchanging the final expander for autogenous cartilage.
Post Tumoral Anopthalmia
 radiotherapy that is frequently required to control orbital tumors causes further
tissue injury.
 delay in the growth of the bone and the soft tissues of the face extends beyond the
confines of the orbit, causing hemifacial hypoplasia, which is manifested by
retromaxillism and nasal, maxillary, and mandibular deviation.
 Surgical objectives
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a. To enable the fitting of an ocular prosthesis and
b. to treat the consequences of the anophthalmic orbit by restoring equilibrium
to the face
Surgical considerations
a. Restore bony orbit
o Onlay bone grafts usually used
o Resorption of onlay bone grafts is greater in the postirradiated orbit, and
an overcorrection is necessary to achieve the desired volume
o Synthetic materials are avoided, especially in irradiated orbits
o Advancing the orbital framework using osteotomies in these patients is
usually considered unsafe, because a segment of irradiated, poorly
vascularized bone runs a high risk of sequestrum formation.
b. Orbital volume
o following enucleation, an implant can be used
 implant is wrapped in autologous fascia (lata or deep temporal) to
reduce its risk of expulsion and may lead to development of
attachments to the extraocular muscles
o Following exenteration, the orbital volume needs to be reconstructed
with autogenous tissue
 Temporalis is flap of choice - Transposition of the anterior portion
is sufficient to fill the orbit and create a vascularized basis for the
overlying grafts that will form the eyelids and the conjunctival sac.
 Excessive filling risks the forward propulsion of the future
prosthesis, whereas transposition of insufficient muscle gives a
final appearance of enophthalmos.
c. Conjuctival sac
o Conjunctival sac and its fornices serve to maintain, humidify, and
articulate the ocular prosthesis
o Buccal mucosal graft – tissue of choice for conjuctival reconstruction
o SSG may be required for complete sac reconstruction post exenteration
d. Eyelid
o Requires multistaged reconstruction
 Horizontal incision through flap to create palpebral fissure
 Upper lid levation may be reconstructed using frontalis sling
 Eyelash grafts are performed 1 month before the creation of the
palpebral fissure
 eyebrow grafts are performed using the contralateral eyebrow if it
is sufficiently thick. Otherwise, eyebrow tattoos or occipital
micrografts give a good result.
 Osseointegrated titanium implants may be used to support an
external prosthesis
Reconstruction following maxillectomy and orbital exenteration
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Rectus abdominis flap is the flap of choice for large defects
inset into orbital exenteration cavity. Skin paddle reapproximates palate. Rectus
abdominis muscle fills orbital cavity. Pedicle is tunneled through midface.