Lacrimal Surgery

Overview

Dacryocystorhinostomy (DCR) is the definitive surgical treatment for nasolacrimal duct obstruction that has not responded to conservative or less invasive measures. The typical candidate is an adult with acquired obstruction, though a child with failed probing fits the same indication. Rather than reopening the diseased duct, DCR bypasses it: the surgeon builds a new, direct channel between the lacrimal sac and the middle meatus of the nasal cavity through the thin bone separating them. That bony opening is the rhinostomy. Once it epithelializes, tears drain straight from the sac into the nose without ever passing through the obstructed duct.

DCR is indicated whenever the level of obstruction localizes to the duct or the sac itself, downstream of a functioning canalicular system: a positive regurgitation sign on sac palpation, a mucocele at the medial canthus, or recurrent dacryocystitis all point here. Success depends on a handful of consistent anatomic landmarks. The two main technical variants, external and endonasal, differ mainly in how the surgeon reaches the bone, not in what the operation ultimately accomplishes.

DCR Surgical Anatomy Landmarks

The lacrimal sac sits in the lacrimal fossa on the anteromedial orbital wall, bounded by the anterior lacrimal crest of the maxillary bone and the posterior lacrimal crest of the lacrimal bone. The bone overlying the sac, particularly the lacrimal bone itself, is thin enough to be removed with a punch or drill. That removal creates the osteotomy, the surgical opening between the sac and the nasal mucosa that the rhinostomy is built around.

The landmark that matters most for safety is the fovea ethmoidalis, the roof of the ethmoid sinus complex and the floor of the anterior cranial fossa, sitting immediately superior to the surgical field. The ethmoid air cells lie directly medial and superior to the lacrimal fossa, so an osteotomy carried too far superiorly risks breaching the fovea ethmoidalis and entering the cranial cavity. Intracranial injury and cerebrospinal fluid leak are real risks here, not textbook abstractions, which is why surgeons deliberately keep the dissection inferior to this landmark.

External vs. Endonasal DCR

Both approaches build the same anastomosis between sac and nose; they differ in surgical access. External DCR uses a small skin incision at the medial canthus, giving the surgeon direct, open visualization of the lacrimal fossa and the sac before the osteotomy is created and the sac wall is marsupialized to the nasal mucosa. It leaves a fine scar. Traditionally it has also been considered the higher-success, more versatile approach, especially when sac anatomy is distorted by prior infection or scarring.

Endonasal DCR is performed entirely through the nose with an endoscope, leaving no external incision and no visible scar. The surgeon works from inside the nasal cavity to raise a mucosal flap, drill the osteotomy, and open the sac from that side. It avoids any risk to the medial canthal tendon or angular vessels that an external incision passes near, and success rates in modern endoscopic series approach those of the external approach in experienced hands. The trade-off is a narrower, more technically demanding working corridor and a steeper learning curve.

Conjunctivodacryocystorhinostomy (CDCR) and the Jones Tube

Standard DCR only works if the canalicular system proximal to the sac is intact and functional. A new opening into the sac is useless if tears can never reach the sac in the first place. When the canaliculi themselves are destroyed or irreversibly blocked, from trauma, chronic canaliculitis, severe cicatricial disease, or prior failed surgery, the drainage problem has to be bypassed further upstream.

Conjunctivodacryocystorhinostomy (CDCR) does exactly that. It creates a direct conduit from the conjunctival fornix, through the caruncle area, into the nasal cavity, skipping the canaliculi and the sac altogether. A glass or Pyrex Jones tube keeps this new tract open. Unlike a standard DCR rhinostomy, which epithelializes into a self-sustaining channel, a bare conjunctiva-to-nose tract tends to close on its own if nothing holds it patent. The tube is meant to stay in place indefinitely, not as a temporary stent.

High-Yield Pearls

• The fovea ethmoidalis marks the roof of the ethmoid sinus and the floor of the anterior cranial fossa, the key landmark to avoid violating during any DCR osteotomy.
• External DCR: skin incision, open visualization. Endonasal DCR: no scar, endoscopic, technically harder.
• CDCR with a Jones tube is reserved for a destroyed or non-functional canalicular system, bypassing the canaliculi and sac entirely; the tube is meant to stay in permanently.

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