Conjunctivodacryocystorhinostomy (CDCR)
Definition:
Conjunctivodacryocystorhinostomy is a procedure by which a fistula is created between the medial commissural conjunctiva in to the nasal cavity. A Pyrex glass tube (Jones tube) is placed within the fistula to keep it functioning.
Indication:
1. Canalicular agenesis
2. Canalicular obstruction
3. Common canalicular obstruction
4. Lacrimal pump dysfunction (e.g. facial palsy)
Procedure:
Surgery is ideally performed under general anesthesia. It can also be performed under local anesthesia if the condition warrants.
Step I:
Caruncular incision and conjunctival dissection: A self retaining eye lid speculum is used to provide adequate exposure of the medial conjunctiva. Anterior half of the caruncle is excised using 15 blade. The posterior portion of the caruncle is left intact to protect the medial conjunctiva from inflammation that is associated with contact with the Jones tube.
The anterior edge of the incision is retracted using a fine double hook retractor. The soft tissues overlying the lacrimal bone are spread using blunt dissection. This procedure reveals the underlying lacrimal bone.
Step II:
Bone removal and catheter placement:
An opening is created in the lacrimal gland with the help of high speed drill. The window created should be approximately 8 mm in diameter. A 14 gauge iv catheter that contains an internal trocar is introduced at a 45 degree angle through the window created in the lacrimal bone, penetrating the nasal mucosa to enter the nasal cavity. This procedure is ideally completed under endoscopic guidance.
Step III:
Jones tube insertion and placement:
After measuring the approximate length of the cannula inserted, a Jones tube with 4 mm diameter is inserted via the cannula which is then removed after successful insertion. This step again is endoscopically guided.
Jones tube is anchored in position using Vicryl sutures. The functioning of this tube is checked by instilling fluorescein dye impregnated solution in to the conjunctiva. Its clearance is checked using an endoscope and seeing it drain into the nose through the Jones tube.
