Endonasal dcr
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endonasal dacryocystorhinostomy
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Endonasal (Endoscopic) Dacryocystorhinostomy (DCR)
Definition and Rationale
Endonasal DCR is the surgical bypass of the lacrimal sac and nasolacrimal duct (NLD) performed entirely through the nasal cavity under endoscopic guidance. It treats epiphora caused by distal lacrimal system obstruction, without any external facial incision. The key principle is creating the widest possible marsupialization of the medial wall of the lacrimal sac.
Epiphora (tears draining down the face) must be distinguished from a "watery eye" (thick tear film without overflow) - the former has surgical indications, the latter is usually medical.
Anatomy (Key Landmarks)
Fig. A - Endonasal view: Lacrimal sac lies under mucosa and the frontal process of maxilla. The axilla of the middle turbinate is the key endoscopic landmark.
- Upper 1/3 of sac: just superior to the anterior insertion of the middle turbinate
- Lower 2/3: oriented vertically just under the anterior maxillary line (lacrimomaxillary suture)
Bones covering the sac:
- Frontal process of maxilla (thicker, anterior)
- Lacrimal bone (thinner, posterior)
Structures (Fig. B):
- Superior punctum | 2. Superior canaliculus | 3. Inferior punctum | 4. Inferior canaliculus | 5. Medial canthal ligament | 6. Common canaliculus | 7. Lacrimal sac | 8. Lacrimal duct | 9. Middle turbinate | 10. Lacrimal bone | 11. Inferior turbinate | 12. Hasner valve
The common internal punctum (valve of Rosenmüller) is the critical landmark - it represents the most proximal level manageable by DCR. Pathology proximal to this (canalicular stenosis) cannot be fixed by DCR alone.
Indications
| Indication | Notes |
|---|---|
| Nasolacrimal duct obstruction (NLDO) - anatomic | Best outcomes; complete physical blockages |
| NLDO - functional | Critical narrowings or pump failure; inferior outcomes vs anatomic |
| Dacryocystitis (acute/chronic) | Early endonasal DCR now supported by evidence |
| Dacryoliths | Middle-aged patients |
| Failed external DCR (revision) | Endoscopic approach is ideal for revisions |
| Pediatric persistent epiphora | After failed probing; bony atresia |
Anatomic : functional obstruction ratio = 70% : 30%; anatomic obstructions have superior DCR outcomes.
Cannot be treated by DCR alone: Superior, inferior, or common canalicular stenosis.
Pre-operative Diagnostics
Physical Examination
- Exclude lid laxity, malposition, punctal anomalies, blepharitis
- Palpation over lacrimal sac - reflux of mucopurulence = dacryocystitis = obstruction amenable to DCR
- Dye disappearance test - 2% fluorescein in conjunctival fornix; normal = complete symmetrical disappearance in 5 minutes
- Jones I test - cotton swab in inferior meatus confirms fluorescein flow
Jones II Test (Probing)
- Hard stop: probe impacts medial wall of sac/bone = canalicular system patent = obstrucion is distal
- Soft stop: probe impeded before entering sac = canalicular stenosis = DCR alone insufficient
Lacrimal Irrigation
- Patient tastes saline = rules out complete obstruction but suggests partial/functional block
- No taste = complete obstruction
Radiologic Evaluation
- Dacryocystography (DCG) - anatomic obstruction: dye fails to penetrate to nasal cavity
- Lacrimal scintigraphy - functional obstruction: dye reaches nasal cavity on DCG but fails to clear on 25-min scintigraphy
- CT scan: useful pre-operatively to assess bony anatomy and sac position
Surgical Technique (Powered Endoscopic DCR)
Setup
- General or local anaesthesia
- Topical decongestion (oxymetazoline) + local infiltration (lidocaine with epinephrine) at axilla of middle turbinate
- 0-degree and 30-degree 4 mm rigid endoscopes
Step-by-Step
Step 1 - Mucosal incision
A vertical/H-shaped mucosal incision is made anterior to the axilla of the middle turbinate, over the frontal process of maxilla.
Step 2 - Mucosal flap elevation
Anterior-based mucosal flap is elevated to expose the frontal process of maxilla and lacrimal bone.
Step 3 - Bone removal
- A powered microdebrider with a cutting burr removes the frontal process of maxilla (thicker bone anteriorly)
- The thinner posterior lacrimal bone is removed with through-cutting forceps (Kerrison rongeurs)
- Critical: bone removal must be complete, medial to the entire lacrimal sac - "saucerization" of surrounding bone
Step 4 - Sac identification and opening
- The lacrimal sac is identified by light transillumination from a canalicular probe placed by the ophthalmology team
- The medial wall of the sac is incised with a sickle knife/needle and marsupialised using through-cutting forceps to create anterior and posterior flaps
Step 5 - Mucosal apposition
- Anterior sac flap is anastomosed to anterior nasal mucosal flap
- Posterior sac flap is laid against the lateral nasal wall
- Goal: complete mucosal coverage of the osteotomy site to prevent stenosis
Step 6 - Silicone stent placement
- A bicanalicular silicone stent is threaded from upper and lower puncta, through the canaliculi into the sac, and retrieved endoscopically from the nose
- Ends secured with a clip or cotton swab loop intranasally (no tension on puncta)
- Removed at 3-6 months
Advantages Over External DCR
| Feature | Endonasal | External |
|---|---|---|
| Facial scar | None | Yes (medial canthal) |
| Lacrimal pump | Preserved (medial canthal ligament intact) | Disrupted |
| Blood loss | Less | More |
| Revision cases | Superior access | Difficult scarring |
| Success rate | ~85-95% (similar) | ~85-95% |
| Learning curve | Steeper | More established |
Outcomes
- Success rates for endoscopic DCR are equivalent to external DCR (both ~85-95%)
- Anatomic obstruction > functional obstruction in terms of outcomes
- Inadequate marsupialization of the lacrimal sac is the primary cause of failure
- Children: excellent success rates comparable to adult DCR
- A 2023 network meta-analysis (PMID 37184641) compared external, endonasal, and transcanalicular laser DCR with/without silicone stenting across RCTs
Complications
Common
| Complication | Details |
|---|---|
| Ostial granuloma | Most common; 47% at ostium edge; treat with topical steroids, excision, or intralesional triamcinolone; recurrence <5% |
| Cheese-wiring | Silicone stent under tension tears through puncta; prevented by looping tube before fixation |
| Surgical failure | Inadequate bone removal leaving unopened sac portion → fluid meniscus → increased resistance |
| Haemorrhage | Intraoperative; minimised with decongestion and epinephrine |
| Synechiae | Middle turbinate adhesion to lateral wall |
Rare but Serious
| Complication | Details |
|---|---|
| CSF leak | Due to surgeon inexperience with endoscopic anatomy |
| Orbital penetration | Damage to extraocular muscles |
| Frontal/maxillary sinusitis | Damage to drainage pathways |
| CPAP air regurgitation | 80% of CPAP users may develop post-op ophthalmic symptoms |
Missed lacrimal sac tumour
- Tumour presents in delayed fashion in ~1/3 of DCR failures
- Warning signs: bloody nasal drainage, medial canthal swelling, proptosis
- Common benign: squamous/transitional papilloma; malignant: SCC/transitional cell carcinoma
- Management: combined external + endoscopic extirpation + adjuvant radiotherapy for malignant lesions
Revision DCR
Indications for revision include persistent epiphora with confirmed ostial stenosis/closure on endoscopy. Endoscopic approach is preferred over external for revision as it avoids scarring from the prior external incision. The scar tissue at the ostium is excised, remaining sac mucosa marsupialised, and silicone stent re-inserted.
Key Points Summary
- Goal: widest possible marsupialization of medial sac wall
- Critical landmark: axilla of middle turbinate (upper sac); lacrimomaxillary suture (lower sac)
- Don't miss: common canalicular obstruction (soft stop on probing) = DCR won't work alone
- Success: complete bone removal + mucosal flap apposition + adequate sac opening
- Primary failure cause: inadequate bony removal with incomplete sac opening
- Best team approach: otolaryngologist (endoscopic anatomy) + oculoplastic surgeon (lacrimal system)
Sources:
- Cummings Otolaryngology Head and Neck Surgery, Chapter 49 - Endoscopic DCR
- Scott-Brown's Otorhinolaryngology Head & Neck Surgery Vol 2 - DCR section
- Evereklioglu C et al. Network meta-analysis of DCR techniques. Graefes Arch Clin Exp Ophthalmol 2023 [PMID: 37184641]
- Li J et al. Early endonasal DCR for acute dacryocystitis: meta-analysis. Am J Rhinol Allergy 2024 [PMID: 38444220]
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