Dacryocystorhinostomy

Epiphora, or abnormal tearing, occurs because of blockage in the lacrimal drainage system, which impairs normal tear channeling into the nose. Recurrent infection may also occur as a result of the stagnation. The dacryocystorhinostomy operation, which involves fistulization of the lacrimal sac into the nasal cavity, may alleviate the symptoms. The operative approach to the sac may be external or endoscopic. The latter approach may use rigid telescopes or a microscope.[1, 2]

The endoscopic approach has several advantages, including the following[3] :

• It provides a better aesthetic result, with no external scar.

• It allows a one-stage procedure to also correct associated nasal pathology that may be causative.

• It avoids injury to the medial canthus and/or pathologic scar formation.

• It preserves the pumping mechanism of the orbicularis oculi muscle.

• Active infection of the lacrimal system is not a contraindication to surgery.

• It is especially superior to the external approach in revision surgery.

• It is much less bloody and messy than the external approach.

• Because of the facility of the approach, the perioperative time is shorter.

• The success rate is comparable to the external approach.

The disadvantages of endoscopic surgery include the following:

• It requires specialized training in nasal endoscopic surgery.

• The endoscopic equipment is an expense.

A retrospective study by Jung et al found a 92.7% success rate for endoscopic dacryocystorhinostomy with bicanalicular lacrimal stent insertion (1004 cases out of 1083). Logistic regression analysis detected a relationship between surgical failure and radioactive iodine ablation.[4]

An image depicting the anatomy of the lacrimal drainage system can be seen below.

Toti first described the external approach in 1904; West described the endonasal approach in 1911. The latter approach fell out of favor because of difficult visualization and endonasal access to the lacrimal sac. However, with the newer, rigid telescopes, these difficulties have been overcome, resulting in a resurgence of the endoscopic technique.

As normal access to the nose for the tears is impaired, a neopassage is defined from the lacrimal sac to the nose.

The occurrence of symptoms may be related to congenital or acquired causes.

Acquired causes include recurrent dacryocystitis and canaliculitis; dacryolithiasis; lacrimal system tumors; nasal pathology obstructing drainage; and trauma, which may be iatrogenic. An unidentifiable cause contributes to an idiopathic etiology.

As a result of the blockage of the nasolacrimal duct, normal tear flow into the nose is impaired. This leads to epiphora. The stagnation of tears in the lacrimal sac and the adjacent conduits promotes infection and its accompanying sequelae.

Patients may present to an ophthalmologist with socially unacceptable unilateral or bilateral epiphora interfering with vision. Persistent neglect of the symptom may induce chronic dacryocystitis with purulent drainage from the canaliculi. Inflammation of the skin in the region of the medial canthus may occur with acute exacerbations.

Indications for dacryocystorhinostomy are as follows:

• Socially unacceptable epiphora caused by anatomic or functional lacrimal sac or nasolacrimal duct obstruction
• Chronic dacryocystitis with purulent drainage from the canaliculi
• Inflammation of the skin overlying the lacrimal sac in the region of the medial canthus
• Dacryolith formation
• Benign lacrimal sac mass

A literature review by Vinciguerra et al indicated that the treatments of choice for distal acquired lacrimal obstruction should be endoscopic and external dacryocystorhinostomy. The mean success rates for these procedures were 89.5% and 89.8%, respectively, compared with the following[5] :

• Balloon dacryoplasty - 48.9%
• Probing-stenting - 54.4%
• Polyurethane stent - 73.6%
• Transcanalicular laser dacryocystorhinostomy - 80%

The lacrimal punctum, which lies near the medial end of each lid margin, opens into a canaliculus. The upper and lower canaliculi lead to the lacrimal sac, which lies in the lacrimal fossa formed by the frontal process of the maxilla anteriorly and the lacrimal bone posteriorly. The nasolacrimal duct originates at the inferior end of the lacrimal sac and slopes caudolaterally to open in the inferior meatus of the nose. This opening is protected by several variable folds of mucous membrane that act as valves preventing retrograde air aspiration. The images below give a schematic view of the area of the lacrimal sac.

The aqueous secretion of the lacrimal gland is covered by a film of mucus from the tarsal conjunctiva. This is further covered by a film of oily secretion from the meibomian glands. Evaporation is hence impeded, and the flow of tears occurs from lateral toward the lacus lacrimalis medially.

The palpebral fibers of the orbicularis oculi trigger blinking, a reflex act. Blinking pumps the tears out of the conjunctival sac. During the act, the puncta are turned inward and dip into the lacus lacrimalis. At this time, the lacrimal sac is drawn open, and tears are sucked up through the canaliculi. When the muscle relaxes, the lacrimal sac retracts to its original volume and the tears are pushed down the nasolacrimal duct. The lacrimal drainage system is represented in the image below.

See Nasolacrimal System Anatomy for more information.

Relative ophthalmologic contraindications include the dry eye syndromes. Other contraindications include bleeding dyscrasias and other systemic deficiencies that would jeopardize surgery.

Dacryocystography allows assessment of the lacrimal passage patency by radiopaque dye techniques.

CT scanning delineates anatomy and detects unrecognized disease in the paranasal sinuses and nose.

CT scanning and dacryocystography further define the anatomy of the lacrimal drainage system.

MRI and dacryocystography allow a better view in the absence of bony shadows.

Lacrimal scintigraphy using gamma camera technology allows assessment of functional tear drainage.

Perform a complete ophthalmologic examination, including testing of visual acuity and visual fields and slit lamp examination.

Perform nasal endoscopy to identify a possible cause for lacrimal obstruction and to assess the feasibility of endoscopic manipulation.

Metal probing and irrigation of the lacrimal drainage system allows confirmation of the diagnosis.

Fluorescein dye irrigation of the lacrimal puncta and detection of the dye in the inferior meatus eliminate a diagnosis of complete blockage.

The operation is performed with the patient under local or general anesthesia. The nose is packed with a solution containing 2 mL of 1:1000 epinephrine and 2 mL of 4% Xylocaine. The packing is left in the nose for 10 minutes. A 30° endoscope, 4 mm in diameter, is used. The site of operation, in the area of the anterior attachment of the middle turbinate, is injected with 1% Xylocaine and 1:100,000 epinephrine solution.

The assistant passes a 20-gauge illuminated fiberoptic light probe (eg, Endo-illuminator, Storz) through the upper or lower canaliculus into the lacrimal sac. The light is located endoscopically on the lateral wall of the nose, and its position is noted. The endoscope light may need to be dimmed to visualize the transilluminated light. This position corresponds to the posterior end of the lacrimal sac where it overlies the lacrimal bone.

A 1-cm diameter circle of mucosa is removed at this site of transillumination to expose the underlying bone. An Ellman Surgitron Radiosurgery Unit provides good hemostasis for this excision of mucosa. A portion of the uncinate process may also require removal to gain access. The underlying bone is removed with a drill. Some authorities advocate the use of the holmium:yttrium-aluminum-garnet (YAG) laser for this bone removal.

The thick bone of the frontal process of the maxilla is encountered anteriorly. The infundibulum or an anterior ethmoidal cell may overlie the lacrimal sac. After the position of the lacrimal sac wall is highlighted and confirmed, the light probe is removed. Reprobing with a metal probe allows tenting of the medial wall of the lacrimal sac. Some authorities inflate the lacrimal sac with methylcellulose via the upper or lower canaliculus for easier identification and manipulation. The lacrimal sac is opened with a 45° cutting forceps, and the opening is enlarged to approximately 1 cm, particularly in the inferior direction. No attempt is made at designing flaps.

Metal stents attached to silastic tubing at either end (eg, O'Donoghue DCR set) are passed through the upper and lower canaliculi and recovered through the nose with a Blakesley forceps. The metal stents are cut from the tubing, which is then stabilized to form a continuous loop around the canaliculi. This loop may be a knot or threading across butterfly 23-gauge tubing by two 16-gauge Insyte needles (Becton-Dickinson Autoguard). Alternatively, some authorities advocate the use of an otologic T tube as a stent.[6]

A retrospective study by Longari et al found good results in endoscopic dacryocystorhinostomy that did not use silicone intubation. In the study, of 84 patients (89 procedures), the rate of success at 18-month follow-up—ie, absence of epiphora and dacryocystitis and ostium patency demonstrated by fluorescein irrigation—was 82.2% in patients who received stents and 88.6% in those who did not.[7]

The revision dacryocystorhinostomy is ideally suited for the neophyte endoscopic surgeon. As a result of the preexisting bone deficiency from past surgery, a light probe is not necessary because the metal probe can tent and outline the lacrimal sac area. However, scarring from previous surgery may obscure the anatomy and cause some difficulty.

A study by Lee et al indicated that the use of hyaluronic acid/collagen resorbable gel during endoscopic dacryocystorhinostomy led to a greater anatomic success rate in the report’s subjects, being 96.7% for the eyes of patients who received the compound, versus 86.3% of control eyes, that is, the eyes of patients who did not receive the compound. Functional success rates were 94.1% vs 84.3%, respectively. Moreover, the rate of granulation was lower in the hyaluronic acid/collagen resorbable gel eyes (9.2% vs 32.2%, respectively), as were the rates of postoperative infection (5.3% vs 8.9%, respectively) and revision surgery (2.0% vs 15.8%, respectively).[8]

Instruct the patient not to blow the nose strenuously for 2 weeks. Tobramycin eye drops are prescribed to be used 3 times daily for 10 days. Saline irrigations of the nasal cavity 3 times per day are recommended.

The patient is reviewed 10 days postoperatively, and the nose is cleaned. Future reviews are planned as necessary. The tubing may be removed 2-6 months after surgery by cutting the exposed part at the medial canthus. The patient is then instructed to blow the nose strenuously into a paper tissue. The tubing remnants are then withdrawn through the nose with Killian nasal packing forceps. Excessive granulation formation around the new ostium may require earlier removal of the tubing. If a T tube is used, it may be left in the lacrimal sac for 3-6 months.

Intraoperative complications

Excessive uncontrollable bleeding may require abandoning the operation and reattempting it at a later date. Orbital fat may be exposed. This is best left well alone. Damage to the medial rectus and superior oblique may cause diplopia. Blindness may occur from damage to the intraorbital vessels or optic nerve.

Postoperative complications

Epistaxis may occur within 10 days. Nasal packing is required, and oral antibiotics are indicated. Infection in the nose or orbit may also require antibiotics.

Adhesions may be minimized by meticulous surgery and by avoiding trauma to the middle turbinate and septum or by resecting the anterior half of the middle turbinate.

Cheesewiring of the canaliculi may occur if the stenting is too tight. The stent may need to be loosened or removed. If the stent is too loose, prolapse of the stent into the eye may occur. The stent may need tightening.

The sump syndrome may occur if the rhinostoma is small and high up in the lacrimal sac. This causes tears and mucus to accumulate in the sac and discharge into the eye.

Pyogenic granulomata may occur at the puncta or the site of rhinostomy if the tubing is left in too long. Urgent removal of the tubing is indicated.

Persistent watering may indicate scarring of the rhinostoma and may require reoperation.

Various success rates for primary endoscopic dacryocystorhinostomy are quoted at 82-96%. In the most favorable series, the follow-up care range was 6-12 months.[9]

In revision endoscopic dacryocystorhinostomy for failed primary external dacryocystorhinostomy, success rates are approximately 75%.

This was supported by a retrospective study by Allon et al. The report indicated that the short-term success rate for revision endoscopic dacryocystorhinostomy, following primary endoscopic or external dacryocystorhinostomy, is excellent, but that this rate decreases over time, primarily within the first 2 postoperative years. Following first revision, the immediate success rate was 93.3%, with the yearly success rates calculated annually after that for 5 years being 75.5%, 71.1%, 68.9%, 68.9%, and 68.9%, respectively. Following second revision, the immediate and 5-year success rates were 88.8% and 77.8%, respectively.[10]

A retrospective study by Golan et al suggested that in endoscopic dacryocystorhinostomy, early postoperative results are indicative of the long-term success or failure of the procedure. The study involved 47 cases of endoscopic dacryocystorhinostomy (39 patients), with the investigators finding that in 45 cases, the improvement or nonimprovement of tearing within 2 weeks after surgery mirrored the absence or presence of epiphora at a mean postoperative follow-up of 12.5 months.[11]

Progress in surgical technique must be accounted for by facilitating the operative technique, by reducing the complication rate, or by increasing the success rate of the operation. Unfortunately, financial considerations must also be met within these confines. A 2007 report averred that endoscopic dacryocystorhinostomy is more cost effective than external dacryocystorhinostomy, despite having a lower success rate and greater usage of resources.[12]

The endoscopic technique has several advantages.[3] With the advance of laser technology, various modifications of approach will be defined. The translacrimal transnasal laser-assisted dacryocystorhinostomy using the neodymium:YAG (Nd:YAG) laser was described in 1997.[13]

Failure rates may be reduced by decreasing the adhesions and stenosis at the nasal stoma. Mitomycin C has recently been put to such use, but its efficacy is not conclusive.