SAMI AL-BDAIRAT, MD

ORBITAL IMPLANTS

ANOPHTHALMIA

• Anophthalmia is absence of globe

• Congenital or acquired

ACQUIRED ANOPHTHALMOS

• After enucleation/evisceration/exenteration

enucleation, evisceration, or

secondary implantation surgery

Conformer is placed in the conjunctival

fornices to maintain the conjunctival

space

conformer is replaced with a

custom-made ocular prosthesis typically

fashioned 4–6 weeks

ANOPHTHALMIC SURGERY

• Successful anophthalmic surgery is achieved when the anophthalmic patient obtains a painless, non-inflamed eye socket with adequate volume restoration and an artificial eye that looks and moves almost as naturally as a normal eye.

• The optimal time to achieve the best functional and cosmetic result for the anophthalmic patient is at the time of enucleation

• orbital implant is typically placed at the time of evisceration or enucleation

• ocular prosthesis is fitted subsequently.

DISPOSABLE SIZING KIT

ORBITAL SPHERE INTRODUCER

Stainless Steel

CONFORMERS

Translucent, Polyamide 12

Small 20mm Medium 23mm Large 26mm

• Anophthalmic implant: Material or substance used to replace an enucleated or eviscerated globe (e.g. polymethylmethacrylate, silicone,hydroxyapatite, aluminum oxide, porous polyethylene, etc.)

• Porous implant: Refers to an implant with numerous interconnected pores or channels throughout its structure that permit fibrovascular ingrowth (e.g. hydroxyapatite, aluminum oxide, porous polyethylene)

• Nonporous implant: Refers to an implant that is solid and does not allow fibrovascular ingrowth (e.g. polymethylmethacrylate, silicone)

• Buried implant: an implant that has been placed within the anophthalmic socket with an overlying closed, smooth, uninterrupted conjunctival surface completely covering the anophthalmic implant

• Exposed implant: an implant that does not have an overlying closed, smooth, uninterrupted surface completely covering it. An exposed implant is an unwanted complication postoperatively with any implant

• Integrated implant: an implant that can be directly coupled to the overlying prosthetic eye with a peg system. As there is a small break in the overlying conjunctiva through which the peg protrudes, there is some debate whether this type of implant should also be known as a partially “exposed integrated implant

• Non-integrated implant An implant that has been placed within the anophthalmic socket that has no connection with the overlying prosthetic eye. There is a closed, smooth, uninterrupted conjunctival surface completely covering the anophthalmic implant. Also known as a “buried non-integrated implant”

Peg: A motility coupling post, made of titanium, which permits direct coupling of the implant movement to an overlying prosthesis. Pegs may be inserted within sleeves that are drilled into the anterior aspect of the implant.

QUASI-INTEGRATED IMPLANT• An implant that has been placed within the anophthalmic

socket with a closed, uninterrupted conjunctival surface completely covering an anophthalmic implant that has an irregular anterior surface, allowing indirect coupling (“quasi-integration”) of implant to overlying, modified prosthesis (e.g., Allen, Iowa, Universal, MEDPOR Quad implants). Also known as a “buried integrated implant” or an “indirectly integrated implant.” Recently designed magnetic coupling systems may also be classified as quasi-integrated .

ADVANTAGES OF EVISCERATION OVER ENUCLEATION• Less disruption of orbital anatomy.

• Good motility of prosthesis

• Lower rate of migration ,extrusion , reoperation.

HISTORY• As early as 500 B.C., Egyptians and Romans wore

ocular prostheses (made of clay) designed by pagan priests.

• Johannes Lange in 1555 (Lowenberg, Germany) was the first to mention enucleation (or extirpation as it was called then), no details of the operative procedure were given

• George Bartisch, in 1583 the first recorded description of removal of an eye for treatment of severe ocular disease(Extirpation)

EXTIRPATION METHOD OF BARTISCH

HISTORY• Ambroise Pare in 1579 described the first prosthesis

which was made of metal and coated with paint .

• In 1841 current enucleation technique was established in separate reports (only weeks apart) by O’Ferrall (Dublin) and Bonnet (Paris)

• The first recorded evisceration is credited to James Bear in 1817.

• The first to perform a routine evisceration procedure was Noyes who, in 1874

HISTORY• In 1884, P.H. Mules developed a unique technique for

evisceration, which has proved to be a milestone in ophthalmic surgery. He was the first to insert a hollow glass sphere (the “Mules” sphere) into the scleral cavity after removal of the cornea and intraocular contents

• Since then Sponge, rubber, paraffin, ivory, wool, cork, cartilage, fat, bone, Vitallium, platinum, aluminum, silver, and gold were used as implant.

• By the 1950s, A variety of implant designs were tried with an attempt to indirectly couple the buried implant to an overlying artificial eye by modifying the anterior surface of the implant as well as the posterior surface of the prosthesis. The Allen and subsequently the Iowa enucleation implants were buried integrated ( “quasi-integrated”) implants.

HISTORY• Troutman, Uribe, Iliff, magnetic implants – 1950s and 1960s),

• Universal implant (1987)

• By 1989, spherical implants made of silicone, glass, or polymethylmethacrylate (PMMA) were the implants most widely used by ophthalmic plastic surgeons

• The introduction of coralline hydroxyapatite orbital implants in the mid- to late 1980s in enucleation, evisceration, or secondary orbital implant surgery ushered in a new era in anophthalmic socket reconstruction.

• Several other porous implant materials have since been introduced as alternatives (e.g. synthetic hydroxyapatite, porous polyethylene, aluminum oxide).

IDEAL ANOPHTHALMIC SOCKET

1.A centrally placed, well-covered, buried implant of adequate volume, fabricated from a bio-inert material

2. A socket lined with healthy conjunctiva and fornices deep enough to retain a prosthesis and to permit horizontal and vertical excursion of an artificial eye

3. Eyelids with normal position and appearance, as well as adequate tone to support a prosthesis

4. A supratarsal eyelid fold that is symmetric with the supratarsal fold of the contralateral eyelid

5. Normal position of the eyelashes and eyelid margin

6. Good transmission of motility from the implant to the overlying prosthesis

7. A comfortable ocular prosthesis that looks similar to the sighted, contralateral globe and in the same horizontal plane

IDEAL ORBITAL IMPLANT• Maintain Natural Lid Shape : ability to receive a motility/support

peg, to support the weight of the artificial eye to prevent lower lid laxity and malposition over time .

• Light Weight

• Porosity: The implant must allow vascular orbital tissues to invade its structure to: a) lock it into place and prevent migration, b) allow it to fight infections from within the implant via the vascular bed infiltrating the implant, and c) support "healing from within" of any defect in the conjunctival-Tenon's closure

• True Integration The implant must be directly integrated (e.g., via a peg) with the artificial eye to allow direct transfer of all available movement from the rectus muscles to the artificial eye

• Natural Biocompatibility: the implant must be a natural material and readily accepted by the tissues of the orbit to prevent "synthetic implant syndrome" i.e., pseudocapsule formation around the implant. This pseudocapsule is the body's way of walling off a foreign material

• Non toxic non allergic

CURRENT CLASSIFICATION OF IMPLANTS

• porous or nonporous, and in either category, the implants are non-integrated, integrated, or quasi-integrated

• Porous implants (hydroxyapatite, porous polyethylene, aluminum oxide)

• nonporous implants (silicone,polymethylmethacrylate)

• Quasi integrated (or indirectly integrated) implants may be porous or nonporous and, because of their irregular anterior surface, are partially coupled to the overlying prosthetic eye (e.g., Allen, Iowa, Universal, MEDPOR ® Quad implant).

• non porous Inert spherical implants • Acrylic sphere

•  is the most basic implant.

• Acrylic, or methylmethacrylate,

• non-porous material

• is best used in cases of trauma, such as a severe gunshot wound to the orbit

•  silicone sphere. This non-porous implant is similar to an acrylic implant, but slightly more pliable.

NON POROUS INERT SPHERICAL IMPLANTS

Advantages

• Provide comfort and low rates of extrusion.

• Cost-effective choice in patients.

Disadvantages

• decreased motility and implant migration.

POROUS ORBITAL IMPLANTS hydroxyapatite • Perry (1985) introduced coralline (sea coral)(HA) spheres

• complex calcium phosphate

• regular and complete system of interconnecting pores ( 500-µm pore size )

• secure attachment of the extra ocular muscles

• The most suitable for peg–sleeve system.

•

hydroxyapatite Disadvantages: surface is abrasive Conjonctival thining extrusion or exposure infection. pyogenic granuloma formation, CostySynthetic HA implants developed by FCI Chinese HA Brazilian HALess expensivePoor porous structure

SYNTHETIC POROUS POLYETHYLENE (MEDPOR)• a porous type of plastic

• Less biocompatible than HA

• Well tolerated by orbital soft tissue

• The surface is nonabrasive so extrusion is rare.

They may be used with or without a wrapping material

• extra ocular muscles can be sutured directly onto the implant

SYNTHETIC POROUS POLYETHYLENE (MEDPOR)

• available in spherical, egg, conical, and mounded shapes (MEDPOR ® Quad implant)

• The anterior surface can also be manufactured with a smooth, nonporous surface to prevent abrasion of the overlying tissue (e.g., MEDPOR ® smooth surface tunnel implant – SST™.

ALUMINUM OXIDE (AL 2 O 3, ALUMINA, BIOCERAMIC IMPLANT• porous, inert substance

• permit host fibrovascular ingrowth

• Human fibroblasts and osteoblasts proliferate more rapidly on aluminum oxide than HA suggesting it is a more biocompatible substance than HA

• lightweight and has a uniform pore structure and excellent pore interconnectivity

• The microcrystalline structure is smoother than the rough surfaced Bio-Eye

• A protein coating that forms after insertion prevents the implant from being recognized as a foreign body This inert nature of these implants is a potentially critical advantage in minimizing socket inflammation.

• Less expensive

VARIETY OF SHAPES

Mesh-Wrapped

Egg-Shaped

Spherical

ADVANTAGES OF VICRYL MESH WRAP Facilitates entry into the orbit by decreasing

drag on surrounding structures Allows suturing directly to implant Eliminates need for donor tissue No risk of disease transmission Eliminates second surgical site Absorbable Allows 360 degree entry of fibrovascular

tissue (as opposed to entry through scleral windows)

PEGGING•  Is an option of any of the porous implants, most

commonly done with hydroxyapatite.

• The thought behind pegging is that it improves motility by allowing the pegged surface to fit into a corresponding groove in the back of the prosthesis .

• can promote infection and lead to extrusion

DERMIS FAT GRAFT

ORBITAL IMPLANT SELECTION IN ADULTS

• spherical versus shaped implants, wrapped versus unwrapped implants, and pegged versus unpegged implants.

• In a 2004 survey of orbital surgeons, of 1,919 primary orbital implants used following enucleation, porous polyethylene was used in 42.7% of cases followed bycoralline HA (27.3%), nonporous alloplastic (PMMA, silicone) implants (19.9%), dermis-fat grafts (7.2%), Bioceramic (1.8%), synthetic HA (0.9%), and mammalian bone (0.2%)

ORBITAL IMPLANT SELECTION IN ADULTS

• porous implant between the ages of 15 and 65 years old

• quasi-integrated implant such as the Universal (PMMA – mounded) or MEDPOR ® Quad implant (mounded)

• A nonporous sphere (e.g., PMMA, silicone), wrapped, centered within the muscle cone, and attached to each of the rectus muscles and inferior oblique muscle,

• A nonporous implant simply placed into the orbit, without a wrap and without connection to the rectus muscles ……seventh decade or beyond),

ORBITAL IMPLANT SELECTION IN CHILDREN

• less than 5 years age …..wrapped nonporous sphere implant 16- or 18-mm diameter Exchange with porous and bigger size is possible….autogenous dermis-fat grafts.

• 5 to 15 years age ,nonporous implants, either a PMMA mounded implant (e.g. Universal) or a wrapped sphere (e.g. PMMA, silicone).

EXPOSURE AND EXTRUSION OF IMPLANTpredisposing Factors

1. closing the wound under tension

2. poor wound closure techniques

3. Infection

4. mechanical or inflammatory irritation from the speculated surface of the porous implant

5. Delayed ingrowth of fibrovascular tissue with subsequent tissue breakdown

Preventive measures for implant exposure

• proper placement of the implant within the orbit followed by a two-layered closure of anterior Tenon’s capsule and conjunctiva

• Treatment : If few weeks,

• No infection ,simple reclosure or with a patch graft (e.G., Sclera, temporalis fascia) is required

• If infection is suspected and treated vigorously with topical and systemic antibiotics, an extrusion and removal of the implant may be avoided.

beyond 4–6 months,

• If non porous implant, The defect should not be closed, and secondary orbital implant surgery should be arranged

• If porous,

exposure<3mm >3mm

Treat conservativelyWait 8 weeks for spontaneous closure

no

Close with scleral patch graft

surgical repair is indicatedUsing sclera patch graft or temporalis fascia patch graft

SUMMARY• Ophthalmic surgeons working closely with

qualified ocularists must be focused on restoring a patient’s natural eye appearance with prosthetic motility as near normal as possible.

• We currently prefer implantation of a porous implants, with or without polyglactin 910 mesh wrapp with attachment of all rectus muscles and inferior oblique to the covered implant.

• Pegging may not be appropriate for all implant surgeons or anophthalmic patients.

• We hope in the future….

THANK YOU