Treatments: Orbital Implants

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Reconstructive surgery for patients undergoing the removal of an eye or for patients who already have an artificial eye (ocular prosthesis)

Patients can now benefit from modern reconstructive surgery techniques to gain the best possible cosmetic results.

A patient with a blind unsightly eye		The patient following removal of the eye and placement of an orbital implant

The Hydroxyapatite Orbital Implant (Coral Implant)

What is Hydroxyapatite?

Porous hydroxyapatite is a complex calcium phosphate salt, made from coral, which is similar to human cancellous (spongy) bone with interconnecting tunnels and no dead-ends. When implanted into the eye socket, porous hydroxyapatite is not treated as a foreign substance by the body in contrast to most other implants used in the past, but becomes ingrown with blood vessels and tissue. As a result of this integration with the orbital tissues, the implant resists migration and rejection.

The porous hydroxyapatite implant can be directly coupled with the artificial eye some months after insertion to improve movement by means of a small peg. This fits into a hole drilled through the conjunctiva (the pink membrane which lines the socket) and into the buried implant. The conjunctiva then grows down the sides of this drilled hole. This occurs because the implant by then contains blood vessels that support growth of this tissue. This secondary procedure is, however, only undertaken for patients in whom the degree of movement of the artificial eye is deemed unsatisfactory following the first stage. Nowadays the second stage is rarely required.

	A coral implant		A diagram of a coral implant viewed from the side.		A drilled coral implant showing a well-healed motility peg hole.

Following successful human clinical trials the US Food and Drug Administration authorised the use of these orbital implants in September 1989. Porous hydroxyapatite orbital implants have now become the implants of first choice amongst the leading oculoplastic surgeons world-wide. By January 2009 over 1500 patients had received this implant under Mr. Leatherbarrow's care in Manchester.

What advantages does this implant offer?

This implant offers a number of potential advantages:

It is necessary for the hydroxyapatite implant to be fully ingrown with blood vessels (vascularised) prior to the drilling procedure for the fitting of the motility peg.

Under what circumstances is this implant used?

The hydroxyapatite orbital implant can be used:

Are there any disadvantages associated with this implant?

The implant has a number of disadvantages:

The additional costs involved, namely the cost of the implant, the requirement and expense of the 2nd stage drilling procedure, and the required modifications to the artificial eye.

Additional expense may also be incurred if scans are used to determine whether or not the implant is vascularised and safe to drill. An alternative is to allow a long period of time before proceeding to the second stage (6 months in primary cases and 12 months in secondary/exchange cases). This is favoured by Mr. Leatherbarrow and in no case to date have we encountered problems with failure of vascularisation when drilling has been performed.

Are there any contraindications to the use of this implant?

Although there are no specific contraindications to the use of this implant, some patients are not suitable for implantation due to severe contracture of the socket tissue due to previous serious infections, trauma, or the use of radiotherapy (X-ray treatment). A simple examination of the socket and eyelids can determine your suitability for this procedure.

	A patient who has undergone a left secondary hydroxyapatite orbital implant procedure with placement of a motility peg.

How good are the results of this procedure?

The results of primary implantation tend to be very good indeed. The results of secondary implantation are less predictable as the socket anatomy has been disrupted and the eye muscles are retracted, scarred and difficult to locate at the time of surgery. In experienced hands, however, the results are usually good but the degree of movement is variable from patient to patient.

Might other surgical procedures be required?

This is always a possibility. Sometimes the size of implant used is insufficient to overcome a sunken appearance or hollow appearance in the upper eyelid. If this is unsatisfactory a second type of implant can be used. This is referred to as a subperiosteal implant and is placed beneath the lining of the bone at the outer aspect of the orbit through a small skin incision in the laughter lines at the outer corner of the eye under general anaesthesia.or under local anaesthesia with sedation (“twilight anaesthesia”). Approximately 5% of patients require this. The implant most commonly used for this is Medpor (porous polyethylene).

Alternatively fat can be taken from the outer aspect of the thigh via a tiny stab incision and injected into the back of the socket to improve the appearance of the upper lid hollow. This is referred to as Coleman lipostructure or Coleman fat injections. The same technique is used to improve facial hollows and lines.

Eyelid surgery to deal with a droop to the upper eyelid (ptosis) or sagging of the lower eyelid is occasionally required under local anaesthesia at a later date.

	Patient with right ptosis and artificial eye		Same patient following ptosis surgery

The majority of patients in the past received these implants wrapped in donor sclera - the white of the eye left over from eyes donated for corneal transplants. A wrapping material is important as the implant is very hard and the eye muscles cannot otherwise be attached to the implant. At present our preferred technique is to wrap the implant in a synthetic material which dissolves over a period of a few weeks (vicryl mesh). We often remove a small piece of tissue from the temple behind the hairline (temporalis fascia) to cap the implant as this markedly reduces the risk of the overlying tissues breaking down and exposing the implant. The stitches or staples in this small wound are removed after a week. The choice of material will also depend on your own wishes.

Are there any risks associated with this surgery?

No operation is free from risk. There are risks common to all operations performed under general anaesthesia. The risks are kept to an absolute minimum e.g. the risk of postoperative infection is minimised by a strict aseptic surgical technique and by the use of intraoperative and postoperative antibiotics. Complications in our hands are extremely rare and to date have been very minor.

Is it necessary to undergo the second stage drilling procedure?

No. If you are happy with the results of the initial procedure the second stage drilling procedure may be omitted. Approximately 1% of our patients choose to proceed with the drilling procedure.

How long does the surgery take to perform?

Approximately 1 hr 30 mins.

Is the procedure painful?

Few patients experience much pain after the first 24-48 hours although for some patients (approximately 1 in 10) the pain can be more severe and last for a few days. Pain is usually controlled very well with simple analgesics but stronger ones can be provided. Pain is associated with movement of the normal eye and this can be avoided by simply moving your head instead of your eyes. If you experience much pain or sickness following the surgery an extra night in hospital will be arranged. The postoperative dressing should be worn for 2 days to reduce postoperative bruising and swelling. It is wise to advise your family and friends, including children, that you will be wearing a head bandage, and that when it is removed the eyelids may be quite bruised. You may remove your own dressing to save another journey to the hospital. You will be given written instructions on aftercare before you are discharged home.

How long will I be in hospital?

Usually you will be admitted on the day of surgery and discharged home the following day.

Occasionally a further night in hospital is required in the event of excessive sickness from general anaesthesia. It is wise to plan for a 2 night stay if you have far to travel home. Medicines are available which can reduce feelings of nausea.

How soon will I be able to return to work?

This very much depends on your individual circumstances and the type of work you do. Most people take at least the first week after surgery off. It is wise to take off more time if your work is not in a clean environment. You will be discharged home with a pressure dressing in place and a bandage around your head to keep bruising and swelling to a minimum. This should be kept in place for 2 days. When it is removed the eyelids may be quite bruised. Your eyelids will have been sewn together temporarily with a blue nylon suture (stitch) which is tied over a small clear silicone or red rubber bolster. This is to prevent any prolapse of swollen tissue. The suture is removed at the first postoperative visit 2 weeks after the surgery. This helps to prevent any excess swelling. The suture is usually removed after 2-3 weeks.

Temporary suture tarsorrhaphy

The appearance of the socket can be camouflaged with dark glasses or with tape stuck over the lens of a pair of ordinary glasses. A temporary eye pad may be applied to go home with but this should not be worn continuously. Initially the upper lid will be droopy but this will begin to rise within a few days.

How long will it be before I get my new artificial eye?

The socket has to heal fully before a new artificial eye is fitted. This usually takes a minimum of 8 weeks. If all is well after surgery your ocularist may proceed with fitting arrangements. Please take note that the time this process takes may be longer depending on your own postoperative progress and the demands made on the service.

At 1-3 weeks after surgery a visit may be required for a surgical shell to be fitted by your ocularist. This is a clear plastic shell or conformer which is inserted into the socket to prevent shrinkage. Occasionally this will have been fitted in the operating theatre.

	The typical appearance of an artificial eye		The modified back surface of the artificial eye

How is the second stage drilling procedure performed?

This is performed in the operating theatre under local anaesthetic on a day case basis. Some sedation can be provided if required or a general anaesthetic can be given if preferred by the patient. A few days before the drilling a wax template is made by your ocularist with a hole in the desired position. This is used to mark the surface of the implant to ensure that the drill hole is made in the best possible position.

	A drilling template		A temporary motility peg being placed		A permanent peg in position

You will be given a local anaesthetic injection through the lower eyelid. The drilling takes a few minutes to perform but the whole procedure, taking into account preparation time, make take approximately 30 minutes. A temporary peg with a flat head is inserted into the hole and the artificial eye replaced in the socket.

This will not fit correctly until adjusted. You should take note of this as it will affect your appearance until the necessary modifications have been made later. A permanent round headed peg is then placed and the back of the artificial eye modified to accept the head of the peg (see above).

The latest motility peg is made of titanium and, although more expensive, it can be more easily screwed into the implant avoiding the need for any drilling. This is simpler to perform but can be more painful requiring a short general anaesthetic.

Your artificial eye

This will be made by your Ocularist, Robin Brammar.

http://www.robinbrammar.co.uk

Each artificial eye (ocular prosthesis) is specially made for you, to fit your individually shaped socket and to conform to the shape of your irnplant. It will be hand painted in your presence to match your natural eye colouring. There will be no pain during the procedures and anaesthetics will not be necessary. You will be required to return for three appointments:

First appointment

An impression is obtained of your socket by introducing cream which will set to a very soft, rubbery consistency and will record the shape of your socket. A painting to match your remaining eye is usually made at this stage. This is competed in your presence to obtain the best possible colour match. This appointment usually lasts one hour.

Second appointment

A wax pattern will by now have been produced to fit the plaster model resulting from the impression of your socket obtained during your first appointment. This wax pattern will be tried in the socket and modified by careful sculpturing until an ideal compromise between fit, comfort, mobility, lid-line and contour is achieved. Lastly, the iris/cornea unit is positioned to match the remaining natural eye. This appointment will take about one hour.

Third appointment

This is usually a simple matter of collecting your artificial eye prosthesis. There may be some minor adjustments necessary.

Cleaning

Your artificial eye need only be cleaned occasionally. You may sleep with your artificial eye in, in fact it is advisable to do so. However, when it is removed, it should be cleaned by using hard contact lens cleaner, as the most common problem is irritation and watering caused by a protein build up.

If not cleaned correctly this protein will collect upon the surface of the artificial eye as a crystalline coating which will eventually make the artificial eye feel gritty. The socket lining and the inner surface of the eyelids may become inflamed and sore with discharge in extreme cases.

It is also important to use artificial tear supplements 3-4 times a day and at bedtime. The best drops to use are SYSTANE eye drops.

Annual check ups and replacements

You are advised to return annually for a check up when any small fitting changes will be assessed and your artificial eye will be re-polished to remove deposits and any scratches. You will be advised when your prosthesis needs to be replaced. This can be required every two to five years as your body is constantly changing but this time-scale varies considerably from patient to patient.

Before Surgery

After Surgery

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