(vi) For lachrymal fistula.
Instruments. Small scalpel, forceps, Muller’s speculum (Fig. 166), Axenfeld’s retractor (Fig. 167), straight scissors, horsehair sutures.
| Fig. 166. Muller’s Retractor for Excision of the Lachrymal Sac. | Fig. 167. Axenfeld’s Retractor for Excision of the Lachrymal Sac. |
Operation. Hæmorrhage is the most troublesome part of this operation; it is best controlled by injecting adrenalin (made from the dried gland, ʒj, and ℥j of water) and cocaine, 10%, into the sac a quarter of an hour before operating. Swabs on the end of a glass rod dipped in adrenalin and cocaine may also be used during the operation. A general anæsthetic is desirable, but many surgeons perform the operation under local anæsthesia, produced by injecting 5% cocaine with 1 in 1,000 adrenalin into the tissue surrounding the sac; but the latter plan has the disadvantage that the mixture may cause severe toxic effects, and the patient usually experiences some pain while the upper portion of the incision is being made and the lower end of the sac is being divided.
First step. The internal tarsal ligament is first defined by putting the lids on the stretch. An incision should be made, 15 millimetres in length (5 millimetres of which should fall above the tarsal ligament), backwards and inwards directly over the lachrymal sac. Muller’s retractor is then inserted to retract the wound laterally, the hooks being made to engage the margins of the incision by means of forceps. The superficial fascia and the fibres of the orbicularis muscle are then divided. The internal tarsal ligament in the upper part of the wound, together with the glistening deep fascia, is exposed and divided carefully so as not to injure the lachrymal sac, which is found directly beneath it (Fig. 168).
| Fig. 168. Excision of the Lachrymal Sac. Showing the internal tarsal ligament in the upper part of the wound with the sac lying beneath. | Fig. 169. Excision of the Lachrymal Sac. Showing the method of defining the upper end of the sac. The internal tarsal ligament has been divided and the sac is well pulled forward with forceps. |
Second step. With scissors the sac-wall is then separated from the deep fascia which encloses it, first externally and then internally, the canaliculi being divided. Axenfeld’s retractor is then inserted in the longitudinal axis of the wound ([Fig. 167]). The middle of the sac is grasped with forceps and pulled forward, and the top of the sac is defined and detached. This is frequently difficult owing to the troublesome hæmorrhage which often occurs. The sac is pulled well forward, and the posterior wall is separated, the neck of the sac being divided as far down the duct as possible by means of scissors. A large probe is passed down the duct into the nose. Some surgeons remove the periosteum of the lachrymal bone as well as the sac, which is unnecessary. The wound is closed by three sutures, the middle one including the divided ends of the internal tarsal ligament. A firm dressing should be applied so as to keep the walls of the cavity in contact. In tuberculous cases it is desirable to curette the lower end of the duct after removal of the sac. The stitches are removed on the seventh day.
Complications. These may be immediate or remote.
Immediate. 1. Inability to find the sac. This may happen to a beginner, and is generally due to the fact that the dissection is carried too much inwards towards the nose. It should not occur if the guides to the sac carefully borne in mind, namely, the internal tarsal ligament and, on the inner side, the lachrymal crest, which can easily be felt with the finger or forceps in the wound.