A conjunctivodacryocystorhinostomy (CDCR) is a surgical procedure carried out to create a fistula or channel between the medial commissural conjunctiva into the nasal cavity. The fistula is usually maintained in a functioning state by the insertion of a short Pyrex tube known as the Jones tube. The surgery enables a complete bypass of the lacrimal drainage system and allows tears to drain directly into the nose. It is performed when the blockage in the canalicular ducts (lacrimal ducts) is so extensive that it cannot be reconstructed and drainage of tears needs to be redirected entirely.
Understanding the lacrimal drainage system
The lacrimal drainage system is made up of the puncta, canaliculi, lacrimal sac and the nasolacrimal duct.
- Puncta – The puncta lacrimalia are minute orifices present at the beginning of the canalicular ducts. These are responsible for the collection of tears (lacrimal fluid) secreted by the lacrimal glands.
- Canaliculi – The lacrimal canaliculi are ducts which lead from the puncta lacrimalia into the lacrimal sac. Two lacrimal canaliculi, superior and inferior, are present in each eye.
- Lacrimal sac – The lacrimal sac is present in the depression formed by the frontal process of the maxilla and the lacrimal duct. It serves as the connection between the lacrimal canaliculi which collect tears from the eye to the nasolacrimal duct which then transmit the fluid to the nasal cavity.
- Nasolacrimal duct – The nasolacrimal duct or tear duct is the conduit between the lacrimal sac and the nasal cavity.
What happens in the case of a blockage in the nasolacrimal drainage system?
Any obstruction in the nasolacrimal duct results in the imperfect draining of tears from the eye to the nasal cavity. This manifests as epiphora or persistent and excessive tearing from the affected eye(s). In the case of a blockage in the nasolacrimal duct, a dacryocystorhinotomy is performed to re-establish the drainage system between the lacrimal sac and the nasal cavity.
What happens in the case of a blockage in the canalicular ducts?
Canalicular obstruction could be due to the following reasons:
- Canalicular stenosis – Narrowing of the canalicular ducts takes place. In this case, a canalicular stent can be used to restore the duct and restore the passage of tears through the canaliculus.
- Calanicular reconstruction – The narrowed or obstructed section of the canaliculus is excised and the remaining sections or the duct are anastomosed or joined over the ends of a canalicular stent. This enables the lacrimal fluid to pass through the reconstructed canaliculus with no resistance.
- Canaliculodacryocystorhinostomy – In the case of total obstruction of the common canaliculus, the obstructed canaliculus is excised and the remainder of the canalicular system is connected to the lacrimal sac via a silicone stent.
- Conjunctivodacryocystorhinostomy – However, in the case of extensive narrowing or blockage of the entire canalicular system where no reconstruction is possible, a direct conduit between the caruncle (raised red structure at the inner corner of the eye) and the nasal cavity is made by using a Pyrex tube known as a Jones tube.
What are the complications of a CDCR?
The insertion of the Jones tube as a part of the CDCR may give rise to a few postoperative complications and cause considerable inconvenience to the patients.
- Obstruction of the tube with mucus
- Migration of the tube
- Closure of the soft tissue tract made by the tube upon movement of the tube
- Necessity for periodic removal, cleaning or replacement of the tube under the surgeon’s supervision
- Foreign-body reaction to the tube leading to increased mucus production and pyogenic granuloma
What is the prognosis of undergoing a CDCR?
Despite the considerable complications associated with the Jones tube and its implantation in the body, a CDCR often provides the patient with significant relief from intractable epiphora, thereby significantly increasing his/her quality of life.
In summary, a CDCR is a surgical procedure carried out to circumvent the entire lacrimal drainage system in the case of several canalicular blockage or obstruction. It involves shunting the tears produced in the eye directly into the nasal cavity by means of a Pyrex tube known as the Jones tube. As a result, it alleviates the patient’s symptoms of constant and excessive tearing and blurring vision.
The implantation of the Jones tube and the CDCR procedure involves considerable risks and must only be carried out by a highly experienced oculoplastic surgeon.
Dr. Debraj Shome is a highly experienced oculoplastic surgeon based in India. He has various accolades and medical distinctions to his name.