Part 45 (2/2)
[Ill.u.s.tration: FIG. 146. STREATFIELD'S ENTROPION OPERATION.]
=Instruments.= Beer's knife, fixation forceps, lid clamp (Fig. 145), spatula, and sutures with a gla.s.s bead threaded on each.
=Operation.= The operation is performed under a general anaesthetic.
_First step._ The lid is fixed in a clamp. The surgeon makes an incision in the skin directly above the lash-bearing area throughout the whole length of the lid and parallel to its margin. A second incision is made about 3 millimetres above this, and its extremities are curved downwards to join the first. The piece of skin and orbicularis muscle between them is removed and the tarsal cartilage is exposed.
_Second step._ A wedge-shaped strip is removed from the tarsal cartilage throughout the whole length of the lid, the apex of the wedge reaching just through the cartilage, but not the conjunctiva on its under surface.
_Third step._ Mattress sutures are then inserted. Each suture should have a needle at either end. A bead may be threaded on the st.i.tch to prevent it cutting into the lid margin. The needles are pa.s.sed from the margin of the lid directly above the eyelashes, about 3 millimetres apart, and brought out through the lower margin of the wound. They are then pa.s.sed from within outwards through the tarsal plate and the upper margin of the wound, being brought out through the skin about half an inch above it and tied (Fig. 146). A few points of suture in the skin may be added if necessary.
[Ill.u.s.tration: FIG. 147. ARLT'S OPERATION FOR TRICHIASIS.]
THE TRANSPLANTATION OF THE LASH-BEARING AREA
=Arlt's operation.= =Indications.= The operation is suitable for cases of trichiasis in which part or the whole of the lashes of the upper lid turn inwards and rub on the surface of the cornea.
=Instruments.= Beer's knife, forceps, scissors, sutures, lid clamp.
=Operation.= _First step._ A lid clamp is applied to the upper lid. An incision is made in the intermarginal line and the tarsal cartilage is split behind the lash-bearing area for a depth of about 5 millimetres throughout the whole extent of the lid (Fig. 147).
_Second step._ An incision through the outer surface of the lid above the lashes is made to meet the other at right angles, so that the lashes are carried on a band of tissue attached at each end.
_Third step._ A semilunar piece of skin is then removed by a curved incision above the last, joining it at the outer and inner ends, and the band carrying the lashes is st.i.tched to the upper margin of this incision; the line of the incision along the intermarginal zone behind the lashes is allowed to heal by granulation. The subsequent contraction caused thereby pulls down the band carrying the lashes to a certain extent. It is, therefore, desirable to pull the band of lashes upwards at the time of operation to a greater extent than is required for the final result in order to overcome this tendency for the condition to re-form as a result of cicatricial contraction of the granulating area.
In order to obviate the cicatricial contraction some surgeons cover the area with a graft of mucous membrane.
ECTROPION OPERATIONS
Ectropion may affect the upper lid, but it occurs far more frequently in the lower. Operations undertaken for its relief vary very considerably for the following reasons:--
1. _The cause of the ectropion._ The active or cicatricial form requires different and more extensive operations than the pa.s.sive form, such as occurs after facial paralysis, senile ectropion, or that occurring after blepharitis.
2. _The degree of ectropion_, whether it is partial, affecting merely the lid margin; or complete, affecting the whole lid.
Ectropion of the lower lid is always accompanied by epiphora, owing to the want of application of the ca.n.a.liculus to the lacus lachrymalis. The ca.n.a.liculus is also apt to become obliterated as the result of marginal blepharitis. Before undertaking any of the operations described below this condition must be remedied, either by dilating the ca.n.a.liculus or by slitting it inwards for a short distance (see p. 290), otherwise, even if the operation be successful in restoring the deformity, the overflow of tears causes the patient to pull down the lower lid constantly in wiping them away, and this tends to reproduce the condition.
After many of the operations a temporary tarsorrhaphy is required to keep the lid in position during the process of cicatrization. The temporary bands produced by this operation are so placed on either side of the cornea as not to interfere with vision altogether. Canthorrhaphy is also desirable in some cases, especially when the ectropion affects the outer end of the lid.
The deformity to be overcome in ectropion is not only the turning outwards of the lid; in cases which have existed for any length of time the lid border becomes permanently elongated and requires to be shortened before it will keep in position. The exposed conjunctiva, especially in cases secondary to blepharitis, becomes thickened near the lid margin, and, though it may regain a more or less normal appearance after the lid has been replaced in position, the thickened margin frequently prevents the proper apposition of the ca.n.a.liculus, and in these cases it is often desirable to remove this tissue (see Fergus's operation).
OPERATIONS FOR Pa.s.sIVE ECTROPION
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