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244 18 Socket Reconstruction
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3.1 ml! Therefore, there is seldom any excuse for implanting an implant smaller
than 22 mm Ø.
Some authors recommend the use of ‘sizing spheres’ to determine the ideal
implant volume: “to see what fits”. This logic is flawed as orbital tissues flow at
body temperature and will therefore accommodate a range of implant volumes.
Operative swelling introduces further inaccuracy when using sizing spheres.
18.3.2 Implant Material and Shape
Many different implant materials and shapes have been tried over the years. The
ideal one is yet to be determined. A solid sphere made of acrylic or silicone is currently the best compromise. The flat face of hemispherical implants is much better
at transmitting movement to the artificial eye. Unfortunately, their sharp edges
make them very prone to late exposure and extrusion. Therefore, hemispherical
implants should no longer be used.
Porous or ‘integrated’ implants have enjoyed a vogue due to the theoretical
advantages of (a) implant migration being less likely because of stabilizing scar
tissue ingrowth into their pores and (b) the option of drilling them subsequently,
once they have become fully vascularized, in order to fit a ‘motility peg’ which
directly couples socket movement to implant movement.
Unfortunately, these theoretical advantages are counterbalanced by drawbacks.
The rough, porous implant surface makes these implants much more prone to
erode through the overlying tenons and conjunctiva and become exposed. Many
techniques for patching these exposures have been described. They mostly fail
with time. Porous implant removal for replacement is made difficult by the tissue
ingrowth and requires sharp dissection. The drilling of porous implants to fit a
motility peg has also largely fallen out of favour due to the high complication
rate (40%). Therefore, avoid using porous motility implants as they have minimal
proven advantage and significantly more complications.
Free dermis fat grafts have the advantage of being autogenous and adding to
the conjunctival lining as they epithelialize. Unfortunately, graft volume retention
is very unpredictable, ranging from complete retention to total absorption. For this
reason, reserve them for secondary socket reconstruction.
18.3.3 Implantation Following Evisceration (Fig. 18.4)
18.3.3.1 Steps
1. Incise the empty scleral shell with Stevens tenotomy scissors from the superotemporal edge to the optic nerve (Fig. 18.4a).
2. Make a similar incision from infero-nasally to the optic nerve.
3. Circumcise the optic nerve to release it from the sclera and to complete the
scleral bisection.
18.3 Orbital Implantation (Fig. 18.1) 245
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a b
c d
e f
Fig.18.4 Implantation post evisceration. a Incise the empty scleral shell with Stevens tenotomy
scissors from the supero-temporal edge to the optic nerve. Make a similar incision from inferonasally to the optic nerve. Circumcise the optic nerve to release it from the sclera and to complete
the bisection. b Place the orbital implant within a plastic sheath lubricated with viscoelastic and
insert it into an injection device. c Inject the implant into the orbit between the scleral halves.
d Suture the two scleral halves together in front of the implant with interrupted 6/0 absorbable
sutures. e Suture the tenons fascia over the sclera with interrupted 6/0 absorbable sutures. f Suture
the conjunctiva closed with a continuous 6/0 absorbable suture. g Place a conformer shell (the
largest that fits while just allowing eyelid closure)
g
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Note: You can use a corneal punch to do this, but it can be difficult to align. The
separated scleral halves remain attached by their extraocular muscles.
4. Place the chosen orbital implant (usually 22 mm diameter solid sphere) within
a plastic sheath lubricated with viscoelastic.
5. Put the implant containing sheath into a Carter sphere introducer or similar
injection device.
6. Using the sphere introducer inject the implant into the orbit between the scleral halves (Fig. 18.4b) while an assistant holds the scleral halves apart with
malleable retractors. Remove the introducer and carefully withdraw the plastic
sheath by squeezing while preventing the implant from popping out with it.
Align the scleral halves around the implant (Fig. 18.4c).
7. Suture the two scleral halves together in front of the implant with interrupted
6/0 absorbable sutures (Fig. 18.4d).
8. Suture the tenons fascia over the sclera with interrupted 6/0 absorbable sutures
(Fig. 18.4e).
9. Suture the conjunctiva closed with a continuous 6/0 absorbable suture. Tighten
it until the suture line begins to shorten to make the wound watertight
(Fig. 18.4f).
10. Insert an appropriately sized conformer shell (the largest that fits while just
allowing eyelid closure) into the conjunctival fornices to maintain them and to
prevent conjunctival prolapse (Fig. 18.4g). To do this push the conformer into
the upper fornix first. Then push the conformer posteriorly while momentarily
retracting the lower lid until it flips over the shell.
11. Apply antibiotic ointment and a pressure dressing for one day.
18.3.4 Implantation Following Enucleation (Fig. 18.5)
18.3.4.1 Steps
1. Make two cuts 180◦apart, from the anterior opening to the equator of the
prepared, rinsed, and antibiotic soaked donor sclera shell (Fig. 18.5a).
2. Evert the donor sclera over your finger and then wrap it around the chosen
orbital implant (usually 22 mm diameter solid sphere). Tack the scleral incisions closed with 6/0 absorbable sutures to stop the implant from slipping out
(Fig. 18.5b).
3. Put the sclera covered implant into a plastic sheath lubricated with viscoelastic. Put the sheath into a Carter sphere introducer or similar injection device
(Fig. 18.5c).
4. If the oblique muscles are available place the introducer next to the socket
and suture the oblique muscles to the upper and lower edges of the covered implant’s scleral opening (which will end up posteriorly) in roughly their
anatomical orientations (Fig. 18.5d).
5. Now carefully position the prongs of the sphere introducer into the conjunctival and tenons opening and slowly inject the implant into the rectus muscle
18.4 Orbital Implant Complications 247
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cone making sure that the extraocular muscles and their pre-placed tagging
sutures are splayed and correctly orientated.
6. Carefully remove the plastic sheath by squeezing it, taking care to prevent the
implant from popping out as you do this.
7. Suture the four rectus muscles to the donor sclera anatomically, as in squint
surgery, about 8–9 mm from the optic nerve opening on the scleral shell. This
opening should end up centred between the attached recti (Fig. 18.5e).
8. Close the tenons capsule in front of the implant with interrupted 6/0
absorbable sutures (Fig. 18.5f) Note: Some authors recommend suturing both
the posterior and the anterior tenons openings in front of the implant, reporting
fewer implant extrusions as the benefit.
9. Close the conjunctiva in front of the tenons with a continuous 6/0 absorbable
suture (Fig. 18.5g). Tighten this suture until the suture line starts to shorten,
before tying it.
10. Insert an appropriately sized conformer shell (the largest that fits while just
allowing eyelid closure) into the conjunctival fornices to maintain them and
to prevent conjunctival prolapse (Fig. 18.5h).
11. Apply antibiotic ointment and a pressure dressing for one day.
18.3.4.2 Notes
•
Consider adding a temporary suture tarsorrhaphy as the final step of implantation to prevent excessive chemosis from pushing out the conformer shell.
•
Per operative intravenous antibiotic prophylaxis is current practice at orbital
implant insertion. The evidence for this is now being questioned in line with
the move to reduce antibiotic overuse.
18.4 Orbital Implant Complications
18.4.1 Conjunctival Cysts
Conjunctival cysts form when conjunctival epithelium is inadvertently buried during surgery. As such they are avoidable. If a cyst occurs, it must be meticulously
excised to ensure that all the cyst wall epithelial lining is removed or else the cyst
will recur.
Note: To make visualization easier you can inject the cyst with a dye, such as
methylene blue, prior to excision.
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ab
cd
ef
gh
Fig.18.5 Implantation post enucleation. a Make two cuts 180° apart, from the anterior opening to
the equator of the donor sclera shell. b Wrap it around the orbital implant. Tack the scleral incisions
closed with 6/0 absorbable sutures. c Put the sclera covered implant into a plastic sheath lubricated
with viscoelastic. Put the sheath into an introducer. d Suture the oblique muscles to the upper and
lower edges of the covered implant’s scleral opening in their anatomical orientations. e Inject the
implant into the rectus muscle cone and suture the rectus muscles to the donor sclera. f Close the
tenons capsule in front of the implant with interrupted 6/0 absorbable sutures. g Close the conjunctiva in front of the tenons with a continuous 6/0 absorbable suture. h Insert the largest conformer
shell that fits while just allowing eyelid closure
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18.4.2 Early or Late Wound Dehiscence
Wound dehiscence is mainly due to poor surgical technique. Operative infection
and impaired healing are other possible reasons. If noted early, re-suture the wound
urgently. However, once bacterial and/or epithelial ingrowth have occurred around
the implant such a repair is doomed to fail again. In this situation remove the
implant, wait for the socket to heal, and then perform late secondary implantation.
18.4.3 Implant Migration
The firm attachment of the extraocular muscles to the orbital implant (directly or
indirectly to its covering material) is what holds an implant in place. The tenons
fascia and conjunctiva alone are insufficient to keep the implant within the muscle
cone. An implant can migrate axially forwards or rotate, slipping out of the muscle
cone between the recti.
18.4.3.1 Rotational Subluxation (Fig. 18.6)
Rotational subluxation is easily missed with spherical implants because they still
look spherical when tilted (tilting of a hemispherical implant is obvious). Look for
it by observing implant movement in different gaze positions.
Fig.18.6 Implant rotational
subluxation. a 22 mm
diameter intraconal implant.
b A smaller implant sinks
downwards i n the orbit and
causes an upward rotation of
the overlying prosthesis.
c Equatorial rectus muscle
fixation to the implant =
stable equilibrium. d Anterior
rectus muscle fixation to the
implant = unstable
equilibrium. The posterior
pull of the recti causes
implant subluxation out of
the muscle cone
a b
22mm
c
d
18mm
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Rotational subluxation occurs when the implant slips out of the muscle cone
between two rectus muscles or rotates within the cone if one of the rectus muscle
insertions dehisces. It occurs for one of four reasons:
1. Rectus muscle imbalance: If only the four rectus muscles are attached to
the implant, three of them (superior, medial and inferior rectus) have a net
inward/medial pull. This may overpower the lone lateral rectus outward/lateral
pull causing the implant to rotate medially and sublux, usually infero-laterally
between the lateral and the inferior recti.
Note: Attaching the oblique muscles, which both have a net outward pull, anatom-
ically to the implant, may help to mitigate such rotation imbalance (this remains
to be proved).
2. Isolated rectus muscle dehiscence: If one of the rectus attachments slips during
healing the implant will rotate and sublux anteriorly. Remedy this by finding
and reattaching the slipped muscle surgically.
3. Undersized orbital implant: An implant whose diameter is smaller than that
of the eye that it replaces does not magically remain in the middle of the orbit.
It sinks down due to gravity to rest on the orbital floor (Fig. 18.4a, b). In this
position it is no longer central within the muscle cone and the net posterior
pull of the rectus muscles will rotate the implant by pulling its anterior pole
posteriorly, encouraging the implant to sublux infero-laterally.
4. Rectus muscle anterior insertion: Attaching the rectus muscles at the equator
of the implant creates a rotationally stable equilibrium (the implant is stable in
all gaze directions) (Fig. 18.4c). By contrast, attaching the recti at the anterior
pole of the implant or overlapping them across the front of the implant (as is
recommended by some) results in an unstable equilibrium (Fig. 18.4d) because
the centre of rotation is transferred from the implant centre to the front of
the implant. In this configuration the pull of any rectus muscle disturbs the
equilibrium, the anterior pole is pulled posteriorly, and the implant rotates out
of the muscle cone. I recommend attaching the recti in roughly their anatomical
positions as a practical compromise between the two extreme positions above.
18.4.4 Late Implant Exposure
The tenons fascia and conjunctiva tolerate rotational stresses well. They do not
tolerate crushing force between the implant and a poorly fitting artificial eye
prosthesis. Conjunctival pressure necrosis results in implant exposure. Implant
exposure causes a symptomatic increase in socket discharge. Unfortunately, by
the time a patient presents, epithelial ingrowth and bacterial colonization of the
implant capsule have already occurred. Consequently, surgical patching of the
exposure fails because it merely transforms the colonized implant capsule into
an infected cyst which eventually ruptures again, re-exposing the implant.
Biologically integrated porous implants, such as hydroxyapatite or ceramic (but
not polypropylene), do not have a capsule and can therefore be shaved down to
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remove the necrotic surface until bleeding granulation is reached. The exposure
may then be patched and covered with conjunctiva. Even then, recurrent erosion
often occurs due to the roughness of the porous implant surface.
18.4.5 Post Enucleation Socket Syndrome (Fig. 18.7)
The post enucleation socket syndrome (PESS) comprises:
1. A deep upper lid hollow (superior sulcus).
2. Upper lid drooping (ptosis).
3. A sunken appearance of the artificial eye (enophthalmos).
4. Progressive lower lid stretching from supporting a heavy artificial eye (prosthe-
sis).
5. Upward tilting of the prosthesis (because the undersized implant sinks to the
orbital floor) (Fig. 18.7b).
6. Reduced artificial eye movement.
All the above stem from a primary orbital volume deficit, the result of inadequate enucleation volume replacement (too small an implant). If you look for it,
you will find that a degree of PESS is exceedingly common. The key to prevention and management is adequate volume replacement. If the intraconal implant is
smaller than 22 mm in diameter replace it with a larger one. Additional volume
supplementation may subsequently be required with an orbital floor implant (maximum additional volume 2 ml) or a superior sulcus dermis-fat graft. After fitting
a new lighter artificial eye prosthesis consider lower lid tightening if necessary.
Finally consider possible ptosis correction.
Fig.18.7 Post enucleation socket syndrome (PESS). All the PESS signs stem from insufficient
orbital volume replacement
Deep upper lid Sulcus
Upper lid Ptosis
Enophthalmos
Lower lid laxity
Upward prosthesis tilt
Reduced Movement
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18.4.6 Lower Lid Laxity
The weight of the artificial eye prosthesis applies an insidious stretching force to
the lower eyelid causing it to lengthen over time. As a result, the prosthesis sinks
downward increasing the upper lid hollow (sulcus) and so marring the patient’s
appearance. The remedy is to increase the implant volume to allow a smaller,
lighter prosthesis to be fitted before tightening the lower lid. (Lid margin resection). Shortening the lid without first fitting a lighter prosthesis will fail through
further stretching. Rarely, a fascia lata lower lid sling may be necessary to support
a heavy artificial eye that cannot be reduced in weight.
18.4.7 Upper Lid Ptosis
Upper lid drooping (ptosis) is common in artificial eye wearers. It may be of the
simple ‘involutional’ type that commonly follows eye trauma or surgery. Alternatively, it may be the consequence of a volume deficient socket. A smaller implant
diameter forces the levator muscle to work at a mechanical disadvantage and makes
the levator seem relatively longer. Upper lid ptosis correction is the last stage in
socket rehabilitation. Only consider it once adequate volume replacement, lower
lid tightening, and prosthesis adjustment have all been addressed. Carry it out like
any other ptosis surgery but with the artificial eye in place.
18.5 Take Home Message
•
Always implant.
•
Think big! Use a 22 mm diameter solid spherical implant.
Reference
1. Thaller VT (1997) Enucleation volume measurement. Ophthalmic Plast Reconstr Surg
13(1):18–20. https://doi.org/10.1097/00002341-199703000-00003. PMID: 9076778
Thyroid Eye Disease
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(Grave’s Orbitopathy)
19
Fig.19.1 What big eyes you have cartoon. Depot orbital steroid can alleviate TED
19.1 Overview (Fig. 19.1)
•
Immunosuppression in active (wet) thyroid eye disease.
•
Orbital Triamcinolone injection
•
Inferior rectus recession with lid retractor recession
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023
V. Th a l l e r, Eyelid Surgery, https://doi.org/10.1007/978-3-031-31527-5_19
253
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