Ординатура / Офтальмология / Английские материалы / Eye Surgery in Hot Climates_Sanford-Smith, Hughes_1994

used to suture the conjunctiva they will usually fall out by themselves after a few weeks. If they are used on the cornea they must be removed after a few weeks, because they act like a foreign body and will cause inßammation and possibly infection.

2.Fine monoÞlament nylon of 9Ò0Ó to 10Ò0Ó gauge is another popular suture for intraocular surgery. Nylon is strong and extremely Þne. It is so Þne that the 10Ò0Ó gauge is hard to work with unless using an operating microscope. Nylon is inert and causes hardly any tissue reaction or inßammation in itself. Because it is so Þne and inert a nylon suture on the cornea will become covered by the corneal epithelium. In this way it doesnÕt cause any inßammation. However if the knots and the suture ends are left on the surface of the eye, they will not become covered by the epithelium. Nylon is much harder than virgin silk ,and so these knots and suture ends lying on the cornea will act like sharp and hard foreign bodies. Even when a nylon suture is used under a conjunctival ßap, the stitch ends can protrude through the conjunctiva and cause irritation. Therefore using nylon sutures on the cornea, the knots must be buried in the tissues and not left on the surface. Even under the conjunctiva the knots should be buried if possible. If not the ends should be cut very short so there is no risk of the ends coming through the conjunctiva.

There are two ways of burying the knots with nylon sutures:-

•Insert the needle from the inside of the wound outwards so the two ends and the knot are inside the wound (see Þg. 2.13).

•Alternatively tie the knot on the surface of the cornea as normal and using suture-tying forceps twist the stitch so that the knot then becomes buried (see Þg. 2.14). (This technique will not work for 9Ò0Ó nylon, as the knot is too thick to pass into the cornea).

2-13 Placing the suture with the knot buried

2.14 Rotating the suture to bury the knot

Fig. 2.16 The correct position to hold the needle

Needles

The needles used for suturing the eye are obviously Þne and small and can be easily damaged. They have a ßat lancet point. Nowadays most needles come with the thread attached but it is possible to obtain re-usable needles which can be threaded.This will be a little cheaper. Since the cornea and sclera are tough tissue, blunt needles are very difÞcult to use. If handled incorrectly the needles can bend or even snap. The needle should be held between the tips of a needle holder half-way along its length (Þg. 2.16).

Suture Technique

For intraocular surgery it is very important to adjust the tension of the sutures correctly. If tied too tightly they can cause astigmatism; too loosely and the wound may leak. The needle point should enter the tissue with the needle tip pointing straight downwards approximately 1 mm from the wound edge. Countertraction is applied by holding the wound edge with forceps and this helps to hold the tissues in place. These forceps should be either Þne toothed forceps (Þg. 2.17) or Þne cupped forceps (Þg. 2.18).The cupped forceps are more practical because they are less likely to get damaged. As the needle passes through the tissues the needleholder is rotated and this applies force along the curve of the needle to avoid bending it. The tip of the needle will come out into the wound and should pass through at least half the total thickness of the cornea or the sclera (Þg. 2.19a). The needle is allowed to carry on into the opposite side so that the depth of the suture is equal to avoid a step in the wound.The needle is advanced until the tip is well clear before it is grasped with the needle holder to pull the suture through. In this way the tip is

(c)The two instruments are crossed over to complete the Þrst half of the knot (a double half hitch)

Fig. 2.20 Winding the suture around the needle holder

Fig. 2.21 The complete knot

CHAPTER 3

OPERATING THEATRE PROCEDURES

AND EQUIPMENT

Two things are essential for an operating theatre to run effectively and efÞciently. The Þrst and most important is sterility.The purpose of all the precautions and care taken in operating theatres is to prevent infection occurring at the time of operation.This is particularly important for eye surgery where infection is not just a complication but a disaster. An additional risk in eye surgery is that intraocular damage may be caused by chemicals or inappropriate irrigating solutions entering

the eye.

The second is teamwork. Surgery is not the work of one important person, Òthe surgeonÓ, with a few other people who are not so important doing what they are told. It is the work of a whole team. Everybody in the team is equally important although obviously the surgeon has had a longer training than the others.

The old proverb Òthe strength of a chain is its weakest linkÓ is particularly true for operating theatre staff and procedures (see Þg. 3.1). It only needs one dirty instrument to introduce infection to the eye and destroy it. It only needs one person in theatre to make a mistake with ßuids which are irrigated in the eye, to cause destruction of the corneal endothelium and blindness. Everyone must share the responsibility for safety and sterility.

The reason for all good surgical practice is to make the operating theatre a safe place.

1.Safe for the patient who must be protected from infection and other harm. (The patient is the most important person who needs protection.)

2.Safe for the staff from the risk of needle-stick and other injuries. These can spread Hepatitis, HIV and other infections. In those parts of the world where hepatitis and HIV infections are common, Òevery used needle and sharp instrument is as dangerous as a loaded gun.Ó

3.Safe for the community by careful and safe disposal of soiled materials, especially sharp instruments and needles.

In developed countries most eye surgery takes place in very sophisticated operating theatres dedicated to eye surgery alone, with staff who are fully trained.

In developing countries eye surgery often takes place in general theatres, and some takes place in buildings which may have other uses and are only temporary operating theatres. Often the staff are not fully trained and accredited as nurses or theatre technicians. In spite of these short-comings many surgical teams have to

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cope with a large volume of work and often with very limited facilities.While safety and sterility are obviously the most important aspects of all theatre work, efÞciency is also important because of the large volume of work.

Another aspect of safety in operating theatres concerns looking after unconscious patients receiving general anaesthesia, or resuscitating a patient who may have collapsed. Everyone working in a theatre team should know about Òbasic life supportÓ.This is how to care for an unconscious patient or one who has collapsed. Basic life support means how to maintain a clear airway and how to give artiÞcial respiration to a patient who has stopped breathing, and how to check the pulse and give cardiac massage to a patient who has no heart beat. All theatre staff should regularly practise these skills, so as to be ready if and when an emergency occurs. At least one member of the theatre team should be trained in Òadvanced life supportÓ, which involves taking and interpreting ECGÕs, the use of a deÞbrillator and giving appropriate intravenous ßuids and drugs.

Theatre procedures depend on many different factors: the work-load; the equipment available; the choice of the surgeon; etc. Eye surgery is practised in many different ways especially in developing countries. There are some highly effective units with a massive through-put of cases. On the other hand, there are some surgeons who are only part-time ophthalmologists, and there are many mobile teams working in temporary accommodation. Therefore this chapter only discusses basic principles and guide-lines.

The Theatre Team

It is important to have an adequate number of motivated and enthusiastic staff. If they are dedicated to eye surgery they will have a better understanding of the requirements of both the surgeon and the patient. A happy relaxed atmosphere and good working relationships in the theatre team makes the work much more pleasant and mistakes less likely.

The theatre team should have a leader who takes responsibility for organising the work and making sure all the routine jobs are done regularly.This ensures both the safety and efÞciency of theatre work.

For a regular operating list the basic personnel required are:-

1.A scrubbed assistant to look after the sterile instruments and assist the surgeon.

2.An anaesthetic assistant to give the local anaesthetics, prepare the patients and if required help with any general anaesthetics.

3.A circulating nurse to clean and sterilise the instruments and apply the dressings.

4.A general assistant.

It is often appropriate that the team leader assumes a fairly basic position, such as being the general assistant, in this way he or she can supervise all the other team members.