DCR and Nasolacrimal System (Cadaver)

Nasolacrimal duct obstruction (NDO) is the most common disorder of the lacrimal system. NDO affects patients of every age, resulting in epiphora and dacryocystitis if left untreated. When NDO symptoms progress and can no longer be managed with conservative measures, endoscopic dacryocystorhinostomy (DCR) is indicated. In this case, DCR exploration of the nasolacrimal anatomy is performed on a cadaver. The typical presentation of NDO is epiphora, but the presence of painful swelling of the medial canthus and mucoid or purulent discharge may indicate the presence of dacryocystitis. The approach presented here is similar to the technique described by Tsirbas and Wormald in 2003.¹ This involves the creation of a mucosal flap and subsequent use of the drill to expose the nasolacrimal duct anatomy. Stenting and subsequent marsupialization of the flap are not shown in the cadaveric dissection. Postoperatively, patients are typically advised to use nasal irrigation twice daily with saline for 6 weeks and complete a 1-week course of oral antibiotics and a 5-day course of antimicrobial eye drops.

Nasolacrimal duct obstruction (NDO) is the most common disorder of the lacrimal system and affects patients of every age. Epiphora can lead to painful swelling of the medial canthus and mucoid or purulent discharge infection (dacryocystitis).¹ 

NDO may be due to idiopathic inflammatory stenosis, known as primary acquired nasolacrimal duct obstruction (PANDO). This leads to partial stenosis or complete obliteration of the duct lumen and occurs primarily in middle age and elderly women.¹ NDO may also occur secondary to a variety of infectious, inflammatory, neoplastic, traumatic, and mechanical insults. In these cases, the disease is referred to as secondary acquired nasolacrimal duct obstruction (SANDO).² When a patient’s chief complaint and initial history are concerning for NDO, follow-up questioning focused on prior ocular, systemic, or traumatic disease should be done to distinguish between a primary or secondary etiology. 

An appropriate physical exam includes an external exam of the eyelids, a slit lamp exam, a medial canthus exam, and a thorough endoscopic nasal exam to rule out inflammatory, structural, or neoplastic abnormalities in the nasal passage. Initial therapy for SANDO will depend on the specific etiology with antibiotics for infections, corticosteroids or immunomodulatory therapy for inflammatory causes, and chemotherapy/radiation for neoplasms. Often, conservative measures are insufficient, and patients require surgery.  

Dacryocystorhinostomy (DCR) is the primary surgery for NDO and involves surgically bypassing the nasolacrimal duct.³ A passage is created from the lacrimal sac to the lateral nasal wall, and in some cases, silicon stents are temporarily placed to maintain patency and allow tear drainage.  

At an annual dissection course, Dr. Ellison leads the residents at Duke University in performing a DCR while identifying the relevant nasolacrimal anatomy. The use of picture-in-picture offers our viewers insight into how the lower canaliculus probe is managed with endoscopic assistance.

A 55-year-old female presents with a chief complaint of right eye tearing and conjunctival discharge for several weeks that progressively worsened over the past week. An external exam of the eye, eyelids, and medial canthus reveals a distended, slightly tender lacrimal sac with conjunctival injection. Nasal endoscopy did not reveal any abnormalities of the nasal mucosa. Diagnostic probing and syringing of the lacrimal pathway demonstrated reflux through the opposite punctum, suggestive of stenosis of the common canaliculus or the lower lacrimal pathway.³ A computed tomography (CT) scan of the lacrimal sac, orbit, and paranasal sinuses confirmed NDO of the lower lacrimal pathway. Surgery was scheduled.  

DCR is indicated for patients with NDO who have persistent epiphora despite conservative measures. History and physical examination are typically sufficient to qualify a patient for surgery after initial conservative management is attempted. Additional functional radiologic studies such as dacryocystography, which involves localization of a complete obstruction with contrast, or dacryoscintigraphy, which involves localization of an incomplete obstruction with radionuclide tracers, are both less frequently used due to the sensitivity and prevalence of CT.³ 

The patient is positioned supine with the head slightly extended and the head of the bed raised 20–30°. The procedure is generally performed under general anesthesia (GA). Oxymetazoline-soaked pledgets are placed in the middle meatus and along the lateral nasal wall to promote decongestion. The lateral nasal wall, axilla of the middle turbinate, and uncinate are infiltrated with 1% lidocaine with 1:100,000 epinephrine for hemostasis.⁴ 

A combination of 0° and 30° rigid endoscope can be used to localize the lacrimal sac. Key landmarks include the axilla of the middle turbinate (the roof of the lacrimal sac is situated above the axilla and extends 1–2 mm below this landmark) and the uncinate process. The superior and inferior turbinates should be identified as well along with an evaluation of the nasal septum.  

After ensuring adequate vasoconstriction of the mucosa, a horizontal incision is made above the insertion of the middle turbinate and anterior to the axilla. This incision is extended vertically down the frontal process of the maxilla and should be right above the bone. In this case, a sickle knife is used, but intraoperatively a scalpel, beaver blade, or cautery may be used. The lower horizontal incision is made superior to the attachment of the inferior turbinate. It is important to note that the nasolacrimal duct typically empties via Hasner’s valve into the inferior meatus. 

The mucosal flap is elevated using either a Freer or Cottle elevator to obtain good exposure of the junction of the nasolacrimal duct to the underlying maxilla (lacrimal crest of the maxilla).⁵

After elevating the mucosal flap, a Kerrison bone punch is used to remove bone from the inferior aspect of the frontal process of the maxilla up to the level of the axilla of the middle turbinate. This process is done carefully, ensuring only bone is taken to prevent tearing of the nasolacrimal duct. The bone at the level of the axilla of the middle turbinate is too thick to punch. At this point, a 20° guarded DCR drill is used to remove bone up to 8 mm above the axilla of the middle turbinate to expose the nasolacrimal sac. The guard on the drill protects the mucosal flap and the middle turbinate. Again, this process is done carefully to ensure adequate bone thinning (often referred to as “eggshelling”) with minimal damage to the lacrimal sac itself. 

After adequately exposing the nasolacrimal sac, a probe is inserted into the lower canaliculus via the lacrimal duct to confirm the location of the common canaliculus, which ultimately empties into the lateral wall of the lacrimal sac. If the probe tip can be visualized on nasal endoscopy, this suggests that sufficient bone over the common canalicular opening has been removed and an incision into the lacrimal sac can be made. The main goal is to create a sufficient opening (marsupialization), that allows communication between the lacrimal sac and the nasal mucosa. Some studies support the use of silicon tubes to stent open the canaliculi and prevent scarring of the rhinostomy site.⁶ 

Following exposure of the bone and any necessary stenting, the mucosal flaps can be folded back towards the uncinate process to facilitate marsupialization.⁵ 

DCR for the treatment of NDO has been performed since the early 20th century with the original,  external DCR technique first described by the Italian otolaryngologist, Addeo Toti.⁷ While external DCR was long considered the gold-standard in NDO management, advances in endoscopic technology have afforded surgeons the ability to perform endoscopic DCR (endo-DCR), which has recently grown in popularity.⁸ While the advantages of external DCR include the ability to directly visualize the lacrimal sac and form and suture flaps between the lacrimal sac and nasal mucosa, the major disadvantage is the medial canthal scar and increased post-op morbidity from the skin incision.³ Endo-DCR does not involve an external incision or scar and allows the surgeon to treat concomitant endonasal pathology. Disadvantages include difficulty forming and suturing sac-nasal mucosal flaps.^5,9 Despite key differences in technique, a 2017 Cochrane review revealed there is uncertainty in which method is most effective due to the lack of well-designed randomized control trials.¹⁰ At present, the standard endo-DCR technique, as well as its various modifications, has been shown to be safe and effective in the management of NDO.¹¹

Postoperative care has a major influence on success rates of DCR.¹² Patients are typically advised to use nasal irrigation twice daily with saline for 6 weeks and to complete a 1-week course of PO antibiotics and a 5-day course of antimicrobial eye drops.⁴ The assessment of a successful DCR is based on symptom relief as well as the absence of any objective signs of NDO (epiphora, dacryocystitis).¹³ In fact, detailed patient satisfaction surveys (Lacrimal Symptom Questionnaire14 and NLDO symptom score 15) that assess symptom relief and improvement in quality of life are considered validated indicators of surgical success.

The overall complication rate after DCRs is reported to be around 6%.¹⁶ The most frequently reported postoperative complications relate to the nasolacrimal duct and include hemorrhage, silicone tubing prolapse, and persistent canalicular obstruction, which may require revision DCR.¹⁶ Postoperative ophthalmologic complications are uncommon. Minor complications include temporary ophthalmoplegia and orbital fat herniation, which may be managed conservatively. Major complications of orbital and subcutaneous emphysema, conjunctival fistula formation, and retrobulbar hematoma, require urgent ophthalmologic consultation.¹⁶ 

Red flag symptoms following DCR include fever, severe headache, neck stiffness, light sensitivity, and rhinorrhea, which may indicate rare but severe complications such as cerebrospinal fluid (CSF) leak or meningitis.^17,18 If the presentation is concerning for a CSF leak, evaluation of rhinorrhea for beta-2 transferrin is necessary, and if positive, a high-resolution CT of the paranasal sinuses and temporal bone should be obtained to prepare for surgical management.¹⁹ If the presentation is concerning for meningitis, a prompt assessment of intracranial pressure is necessary. A CT scan should be performed prior to attempting a lumbar puncture, and an opening pressure should be obtained.²⁰

Outcomes after endo-DCR are typically positive, with success rates cited between 84–94%.¹⁶ Success rates are highest in patients without a history of dacryocystitis, sinusitis, or chronic inflammation.³ Given the technical challenge of endo-DCR when compared with external DCR, surgeon experience plays an important role in surgical success as well.²¹ With respect to differences in specific endo-DCR techniques; a 2020 systematic review by Vinciguerra et al. found that there were no differences in outcomes between mechanical and powered approaches in endo-DCR and that mucosal flap preservation was not necessary to achieve a positive outcome.²² 

When compared with primary procedures, revision procedures generally have lower success rates (76.5%).²³ The formation of granulation tissue over the rhinostomy site is the most likely contributor to lower success rates in revision procedures,^24,25 and evidence suggests that an antiproliferative agent such as mitomycin C can be applied postoperatively to improve outcomes in revision endo-DCR cases.^15,26

Future prospective, randomized trials with larger sample sizes are necessary to evaluate the efficacy of endo-DCR versus external DCR as well as intraoperative antiproliferative agents on the rate of healing and surgical outcomes. 

Author C. Scott Brown also works as editor of the Otolaryngology section of the Journal of Medical Insight.

This case is a dacryocystorhinostomy demonstrated on a cadaver; no consent was required. All other people seen in the video consented to the publication of the media.