What are the next steps in managing a patient with failed external Dacryocystorhinostomy (DCR)?

Management of Failed External Dacryocystorhinostomy (DCR)

When external DCR fails, proceed with endoscopic endonasal revision surgery after identifying the specific cause of failure through nasal endoscopy, lacrimal irrigation, and probing. 1, 2

Immediate Diagnostic Evaluation

Before attempting revision surgery, perform a systematic evaluation to identify the cause of failure:

• Conduct nasal endoscopy to visualize intranasal anatomy and identify obstructions, as this is essential for surgical planning 1, 2
• Perform lacrimal irrigation and probing to assess patency and locate the site of obstruction 2
• Order paranasal sinus CT scanning if available, as 94% of failed cases demonstrate at least one CT abnormality 1
• Complete fluorescein dye disappearance test to differentiate anatomic from functional obstruction 2

Common Causes of External DCR Failure

Understanding the etiology guides your revision approach:

• Membranous scarring/obstruction of the ostium is the most common cause (74-100% of cases), representing scar tissue formation at the surgical site 3, 2, 4
• Inadequate bony removal occurs in approximately 72% of failed cases, where insufficient bone was removed during the initial surgery 4
• Intranasal abnormalities including deviated septum (71%), concha bullosa (47%), septal adhesions (47%), and enlarged middle turbinate (41%) 1
• Canalicular occlusion accounts for approximately 11% of failures and requires different surgical management 5
• Nasal synechiae between the lateral nasal wall and middle turbinate (38% of cases) 4
• Improperly positioned bone opening in the wrong anatomical location (24% of cases) 4

Revision Surgery Approach

Endoscopic endonasal revision DCR is the preferred technique, as it provides superior visualization of the ostium and intranasal pathology compared to repeat external approaches 3, 2, 4:

Surgical Technique

• Use powered instrumentation including serrated oscillating blade (required in 89% of cases) and high-speed diamond bur (26% of cases) for precise removal of scar tissue and bone 3
• Perform partial middle turbinectomy in 53% of cases when the middle turbinate obstructs visualization or contributes to adhesions 3
• Complete anterior ethmoidectomy in 21% of cases when additional space is needed or ethmoid disease is present 3
• Ensure adequate bony removal to create a sufficiently large ostium, as inadequate bone removal is a major cause of initial failure 4
• Consider lacrimal ostium stent placement at the end of surgery to maintain patency during healing, with success rates of 83% 4

Adjunctive Procedures

• Address intranasal pathology identified on preoperative evaluation, including septoplasty for significant deviation or turbinate reduction 1
• Perform silicone tube intubation under endoscopy for functional epiphora without anatomic obstruction (13 of 61 cases in one series) 2
• Consult otolaryngology preoperatively when significant sinonasal disease is present, as this improves surgical outcomes 1

Special Consideration: Canalicular Obstruction

If canalicular occlusion is identified as the cause of failure:

• Perform canaliculorhinostomy or canaliculodacryocystorhinostomy using microsurgical techniques 5
• Counsel patients that success rates are approximately 50% for long-term patency when canalicular obstruction is present 5
• Consider conjunctivorhinostomy for severe proximal canalicular disease 5

Expected Outcomes

• Overall success rate of endoscopic revision surgery is 79-90% when measured by both anatomic patency and functional resolution of epiphora 3, 2
• Anatomic success (patent on irrigation) approaches 100% with endoscopic techniques 3
• Mean follow-up of 12-15 months is recommended to assess long-term patency 3, 2

Critical Pitfalls to Avoid

• Do not perform repeat external DCR as the first revision approach, since endoscopic visualization is superior for identifying and addressing ostium scarring 3, 2
• Do not proceed with revision surgery without identifying the specific cause of failure, as multiple etiologies may coexist in the same patient (47% of cases) 3
• Do not ignore chronic symptom duration, as longer chronicity before initial surgery significantly increases failure risk 1
• Do not overlook pathologic findings such as allergic rhinitis, which significantly correlates with failure rates 1
• Do not delay revision surgery excessively, though the average interval is 15 months, earlier intervention may prevent progressive scarring 2