=The 'cold method'= of paraffin injection is by far the most satisfactory, for the following reasons:--

(_a_) The temperature need not be so high, and no damage is therefore done to the tissues.

(_b_) It is more easily regulated (see Vol. I, p. 682).

(_c_) Embolism is less likely to occur.

=Instruments.= Fixation forceps, tenotomy knife, speculum, a large paraffin syringe, and a short needle having a big bore.

=Operation.= This may be performed under adrenalin and cocaine.

_First step._ The stump is drawn forwards with forceps. A tenotomy knife, inserted well to the outer side of the stump, is then swept freely round and a pocket is formed in the centre of the orbit into which the injection can be made. The tenotomy knife is then withdrawn.

_Second step._ The sterile melted paraffin (melting-point 115 F.) should be poured into the syringe, which should have been previously kept in a hot-water bath. The paraffin is then allowed to cool slowly until it just becomes opalescent. The injection should be made through the hole made by the tenotomy knife, sufficient paraffin being inserted to obtain the desired result. The operation is usually followed by considerable swelling of the tissues, which will subside in three or four weeks.

OPERATIONS FOR THE RESTORATION OF A CONTRACTED SOCKET

As the result of wearing badly-formed artificial eyes or of subsequent inflammation in the conjunctival sac, the socket not infrequently becomes so contracted that the prosthesis cannot be retained.

Enlargement of the sac may be obtained by two methods:--

(_a_) Skin-grafting (Thiersch's method).

(_b_) Transplantation of skin from the surrounding structures (Maxwell's operation).

SKIN-GRAFTING

=Indications.= This procedure is especially suitable for cases in which the base of the socket opposite the palpebral aperture has to be enlarged, and it is usually performed prior to Maxwell's operation for the restoration of the fornices in severe cases.

=Instruments.= Scalpel, speculum, skin-grafting razor, probes, and a piece of thick style wire.

=Operation.= _First step._ The base of the socket is freely divided in a horizontal direction opposite the palpebral aperture so as to produce a gaping wound.

_Second step._ This gaping wound is put on the stretch in the following way: A thick piece of style wire is bent round to fit into the fornices of the socket, the ends being brought out over the lid at the inner canthus. The circle of wire is opened out as far as possible so as to put the wound at the bottom of the socket on the stretch to its fullest extent.

_Third step._ Skin grafts are then cut from the inner surface of the arm (see Vol. I, p. 670), applied by means of probes, and pressed down on to the raw surface. No dressings should be applied directly to the grafts, but a watch-gla.s.s may be placed over the palpebral aperture and dressings applied over it. The style wire should be removed on the fourth day.

INCLUSION OF FLAPS. MAXWELL'S OPERATION

=Indications.= It is especially useful for the enlargement of the socket by the formation of new fornices. As a rule it is performed for the reproduction of the lower fornix, as it is frequently due to the obliteration of this cul-de-sac that the artificial eye cannot be retained. The operation, however, may be modified and applied to the formation of both the upper and outer culs-de-sac.

=Instruments.= Scalpel, forceps, scissors, and sutures.

=Operation.= A general anaesthetic is required.

_First step._ An incision is made in the lower fornix throughout its whole length and carried downwards for a distance of about half an inch (Fig. 137, A).

_Second step._ A crescentic piece of skin is marked out on the lower lid by two incisions which have their concavity directed upwards. The upper one is parallel with the margin of the lower lid and about 5 millimetres below it. This crescentic flap is then dissected up from the deeper tissues all round, except for a small pedicle at its centre (Fig. 137, B).

_Third step._ The incision forming the upper margin of the crescentic piece of skin is deepened until it meets the incision made in the fornix, so that the lower lid is converted into a band of tissue attached only at each end.

[Ill.u.s.tration: FIG. 137. MAXWELL'S OPERATION FOR CONTRACTED SOCKET.

_First step._ A is the incision through the conjunctiva. The flap of skin from the outer surface of the lower lid is entirely raised from the subcutaneous tissue, except for the pedicle B which holds the new fornix in position.]

[Ill.u.s.tration: FIG. 138. MAXWELL'S OPERATION. _Final step._ Showing the flap of skin from the outer surface of the lower lid turned in to form the new lower fornix. The surface wound has been closed by sutures.]

_Fourth step._ The upper margin of the incision in the fornix is st.i.tched to the upper margin or concavity of the crescentic piece of skin after the latter has been displaced upwards beneath the band of tissue carrying the lashes, and the lower margin of the crescentic piece of skin is st.i.tched to the conjunctival edge of the band, so that the crescentic piece of skin is folded on itself and forms the new lower fornix, being held down in its position by the pedicle (Fig. 138). The sutures should be of catgut, as their subsequent removal is somewhat difficult.

_Fifth step._ The surface wound is closed by silkworm-gut sutures. The socket should be packed with gauze, or else a piece of style wire should be inserted, as in the previous operation, so as to maintain the groove in the new lower fornix.

CHAPTER VIII

OPERATIONS UPON THE EYELIDS

SURGICAL ANATOMY

The eyelids consist of well-marked planes of tissue, which are, from without inwards--

1. Skin with very little subcutaneous fat.

2. Orbicularis muscle.

3. Tarsal plates, which are attached to the orbital margins by the palpebral ligaments and which thereby form a barrier to the pa.s.sage of infection backwards into the orbit.

4. Subconjunctival tissue and conjunctiva.

It is most important for successful results that flaps and incisions should be made accurately down to and in the correct layer of the lid.

Along the lid margin, between the eyelashes and the posterior border of the eyelid, is a white line (intermarginal line) formed by the edge of the tarsal plate. In the many operations in which the lid is split the incision is carried along this line.

The blood-supply to the eyelids is derived from arterial arches--two in the top lid, and one in the lower--which run parallel to the margins. As far as possible, therefore, flaps should be planned with their bases at right angles to the course of the vessels. The extreme vascularity of the lid, together with the small amount of subcutaneous fat, allows of almost complete detachment of flaps of skin without fear of necrosis, but at the same time every care should be taken to avoid injuring these flaps when manipulating them. Haemorrhage is controlled during the operation by means of clamps or by direct pressure of the lid between the finger and thumb. As a rule a general anaesthetic is required for most of the operations.

SUTURE OF WOUNDS OF THE EYELIDS

_Wounds which involve the skin only_ are brought together in the ordinary way with a few fine sutures. In wounds of the upper lid care should be taken to suture the levator palpebrae, if divided, as otherwise traumatic ptosis may result.

_Suture of wounds involving the lid margin._

(_a_) In _simple division_ the margins of the lids are brought together by means of a fine suture; the conjunctival surface is first approximated, and then the skin by a deep suture which includes the tarsal cartilage. Accurate apposition of the lid border is very essential. Unfortunately a certain amount of ectropion frequently follows, which may require for its relief one of the operations given below (see p. 284).

(_b_) _Occasionally the lid margin carrying the lashes may be torn off._ As a rule, the strip remains attached to the lid. It should then be accurately sutured in position, taking care that the lashes take their correct turn outwards. In cases where the strip is torn off entirely, the skin and conjunctiva should be sutured together. When large portions of the lid are lost, some form of plastic operation, such as is performed for making a new lid, is required (see p. 287).