Tube Placement

The following steps are taken for tube placement:

1. Caruncle bipolar electrocautery is performed prior the tube placement to reduce the caruncle (Fig. 12.5). It gives a better access to the entry at the medial canthus. Electrocautery is preferred to cutting a caruncle because it makes hemo-stasis, and the conjunctiva has a less tendency to cover later the tube.

2. A needle (or a guide wire) is passed in the medial canthus from the site of the caruncle (or anterior/inferior caruncle) into the nasal cavity in the inferomedial direction. Viewing endo-nasally with Hopkins endoscope can confirm that the needle positioning is correct and the length of the tunnel can be measured.

3. The tunnel is cut with the help of a Graefe knife along a needle into the nasal cavity through the soft tissues while the cornea is preserved with a protector (Fig. 12.6). The opening of the tunnel can be enlarged with moving the knife inferi-

Medial Canthal Ligament
Fig. 12.5. Electrocautery of the caruncle gives good access to the entry at the medial canthus. (From [14])

orly and then superiorly, if necessary (the knife end is pushed and pulled with short movements in superior and inferior directions to enlarge the track) and its intranasal positioning can be confirmed endoscopically.

Tunnel 4mm Length of a Tube

A tube should be approximately 2-4 mm longer than the length of a tunnel, because success of the procedure depends on accurate positioning of the tube. The tip of the Graefe knife is controlled endoscopically to be 2-4 mm over the lateral nasal wall and the edge of the knife is grasped at the medial canthus with a hemostat of tweezers and the Graefe knife is then withrawn. This process provides a measure of the distance from the medial canthus to the knife tip and the determination of an appropriate length of the tube [20].

a guide wire. A Jones tube is put into the luminous end of Thiemann catheter not farther than 2 mm. The catheter tip is put into the cut tunnel from the caruncle and the catheter placement is controlled en-donasally with endoscope. The tip is caught with forceps and pulled out of the nose and thus a glass tube is gently inserted into the tunnel. At this moment the flange of the tube is fixed with forceps in the medial canthus and the catheter is drawn out of the tube. The correct placement of a tube and its length are controlled endoscopically. Tube Fixation Tube Insertion

A tube is inserted with the help of Thiemann urologi-cal catheter, the outer diameter of 8 Charrier, or with

The tube is fixed with a Prolene suture 8-0 around its neck to the medial part of the lower eyelid. The suture is removed in 4-6 weeks. A Jones tube with a hole at the neck makes suturing easier.

Cdcr Drawing
Fig. 12.7. The CDCR with an external approach. Tube is inserted into the tunnel after the posterior nasal and lacrimal sac flaps were anastomosed. (From [14])

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