The goal of this protocol is to present transcanalicular laser-assisted dacryocystorhinostomy as a minimally invasive approach in the treatment of primary acquired nasolacrimal duct obstruction.
Today's gold standard in the treatment of infrasaccal primary acquired nasolacrimal duct obstruction (PANDO) is external dacryocystorhinostomy (DCR), a relatively invasive procedure that can be performed after failure of recanalizing treatments. However, with progress in the field of diode laser technology, new approaches have emerged. Laser-assisted transcanalicular DCR with subsequent bicanalicular silicon intubation is a new option showing great promise as a viable minimally invasive procedure. Under permanent endoscopic visual control from the nasal cavity, a diode laser fiber is inserted into the lacrimal sac and laser energy is applied to create a bony ostium between the lacrimal sac and the nasal cavity. Since no skin incision needs to be made, advantages of this method comprise the sparing of the skin as well as the medial palpebral structures and the physiological palpebral-canalicular pump mechanism. The duration of surgery as well as reconvalescence is generally shorter than with external DCR. Complications include silicon tube prolapse, mild swelling and, rarely, canalicular infection and thermal injury. One-year functional success rates, defined as complete resolution of symptoms and ostium patency, are high, yet still range behind those of external DCR. However, secondary external DCR after failure of laser-assisted DCR can be performed without difficulty. Thus, laser-assisted transcanalicular DCR is a valid option that should be considered as a second-step procedure after failure of recanalization procedures and before external DCR.
Infrasaccal primary acquired nasolacrimal duct obstruction (PANDO) is a common disorder in middle-aged and older patients leading to chronic epiphora and blepharitis as well as recurring or chronic dacryocystitis. Most commonly, patients develop an infrasaccal obstruction of one or both nasolacrimal ducts, resulting in insufficient tear drainage.
In the treatment of PANDO, external dacryocystorhinostomy (DCR) is still considered to be the gold standard, even though this procedure historically dates back over a hundred years to when it was first performed1. After skin incision and preparation of the nasal wall of the lacrimal sac, a drill is used to create a bony ostium leading to the nasal cavity, thus bypassing the obstructed duct. Functional success rates above 85% have been reported for this method2,3. These results, however, come at the cost of performing a relatively invasive procedure that puts at risk the medial structures of the eyelid including the physiological canalicular pump mechanism4,5 and may leave patients with an unwelcome scar, although modern nasojugal skin incisions have improved results. These risks are potentially avoidable by performing less invasive techniques or choosing an endonasal approach.
In order to circumvent invasive surgery, much work has been done in the field of minimally invasive tear drainage recanalization. Two methods in particular have been established as potential first-step procedures: microdrill dacryoplasty and laser-assisted dacryoplasty. These procedures are based on transcanalicular endoscopy of the tear drainage system and can be performed to treat for short-segment membranous stenoses of the nasolacrimal duct. Though only minimally invasive and characterized by quick reconvalescence, a common drawback of these recanalizing techniques are the relatively low functional success rates with regard to long-term outcomes6,7,8,9.
In an effort to fill the void between these first-step procedures and external DCR as a definitive treatment, new approaches have recently been developed. The most promising of which is laser-assisted DCR for the treatment of absolute infrasaccal PANDO. Like with all aforementioned approaches, patients are recommended to be put under general anesthesia for this procedure. A diode laser fiber is inserted via either canaliculus and is then advanced into the lacrimal sac. Next, laser energy is applied to the lateral nasal wall until a bony ostium is created, connecting to the nasal cavity at the height of the middle turbinate's anterior margin10,11. All the while, constant visual control is kept using endonasal endoscopy. The newly formed anastomosis serves as a bypass for the tear drainage. After successful irrigation, bicanalicular silicon intubation is performed to prevent early scarring of the newly formed ostium. Postoperative treatment consists of decongestant, steroidal and antibiotic eye drops to prevent swelling, inflammation, and infection, respectively.
The duration of surgery as well as reconvalescence is generally shorter than with external DCR (10 – 25 min in laser-assisted DCR vs. 35 – 75 min in external DCR). Complication rates are relatively low, the most common being discrete swelling of the eyelids and silicon tube prolapse. Canalicular infection and thermal injury are rare events10. One-year functional success rates of 74 – 88% have been reported10,11,12,13,14,15,16,17,18, thus ranging closely behind those of external DCR without suffering the disadvantages of the external surgical approach. However, long-term results remain yet to be provided. Additionally, even after failure of laser-assisted DCR, secondary external DCR can still be performed without difficulty. Consequently, laser-assisted DCR qualifies as a viable second-step procedure that should optimally be performed after failure of recanalization surgery and before external DCR.
For this procedure, informed consent is required and has been obtained for every patient who has undergone surgery in the Department of Ophthalmology, University of Cologne, Cologne, Germany. All examinations and surgical interventions were executed in accordance with national laws and the declaration of Helsinki from 1975 in its current version.
NOTE: Unless indicated otherwise, instructions will always only refer to the side on which the procedure is being performed. Use sterilized equipment.
1. Patient Preparation
2. Laser-assisted DCR
3. Post-op Care and Follow-up
Optimal result:
The procedure as described above takes about 10 – 25 min and is usually tolerated very well. Upon examination the next day, a little swelling of the eyelid can be present in about 60% of cases. This little swelling always resolves completely within a maximum of three days. Patients do not complain about pain, silicon prolapse or signs of injury or infection. However, due to bicanalicular silicon intubation being performed during the procedure, epiphora may persist until the tubes are removed. Topical application of antibiotic, steroidal, and decongestant eye postoperatively is essential and patients need to follow instructions closely for optimal results. At three months after surgery, silicon tubes can be removed easily. In optimal cases, complete and permanent resolution of symptoms can be observed. Table 1 gives an overview of the results of this technique, previously published by Koch et al. in 201610.
Sub-optimal results:
Although relief of symptoms initially occurs in most patients, about 20 – 25% of patients, who have otherwise had little to no complications, show incomplete resolution of symptoms at the six-months mark. The most likely reason for this is scar tissue forming in the bony ostium. In these cases of recurring stenosis, secondary external DCR can become necessary.
Complicated cases:
Serious complications are rare. When the utilized laser equipment is not handled carefully, the tip of the laser fiber can slip back into the metal cannula which will cause heating of the metal. This results in thermal injury to the canaliculus or lacrimal sac. Penetrating injuries due to necrosis of the tear drainage system require suturing and, possibly, a displacement flap to close the defect. Affected patients need to be followed up more closely as the lesion facilitates scarring and an ensuing obstruction as well as infections. Secondary external DCR and canaliculus reconstruction surgery can become necessary in these cases.
Figure 1. Pre- and postoperative portrait photos of a 73-year-old patient who underwent transcanalicular laser-assisted DCR of the left side.
a Preoperative appearance. b Mild swelling of the lower eyelid on the first postoperative day, resolving completely within two days. Please click here to view a larger version of this figure.
Figure 2. Experimental Walkthrough
a. Dilation of the upper punctum using a lacrimal probe. Dilation has to be performed bicanalicularly to facilitate silicon intubation later.
b. The laser fiber is inserted into the handpiece and the blunt cannula. Subsequently, it is inserted into the lower canaliculus.
c. Correct placement of the laser fiber. After inserting the cannula, the tip is pointing in an antero-inferior direction, aiming for the anterior margin of the middle turbinate.
d. The aiming beam of the laser appears approximately at the anterior margin of the middle turbinate. Laser energy is applied to create an ostium.
e. As the tissue between the lacrimal sac and the nasal cavity grows thinner, the light becomes brighter. Breaching of the wall is imminent.
f. Shortly after breaching the wall. The tip of the laser fiber can be seen sticking through the newly formed osteotomy.
g. Silicon intubation of the lower canaliculus.
h. Intranasal image during silicon intubation of the upper canaliculus. The first silicon tube is already in place (lateral side) while the leading metal tip of the second silicon tube is sticking out of the ostium. Please click here to view a larger version of this figure.
number of patients | 48 |
male | 11 |
female | 37 |
mean age (years) | 60 ± 11 |
surgical success rate* | 94% |
functional success rate (6 months)** | 78% |
postoperative lid swelling | 64% |
canalicular infection | 2% |
thermal injury | 2% |
silicon tube prolapse | 9% |
* defined as postoperative bypass patency | |
**defined as complete resolution of symptoms |
Table 1.
Overview of the results of laser-assisted DCR as described in this protocol. Data previously published in Klin. Monbl. Augenheilkd. by Koch et al. in 201610.
Transcanalicular laser-assisted DCR as described above is a fairly quick, minimally invasive way to treat absolute infrasaccal nasolacrimal duct obstruction effectively without the need for skin incision, thus sparing not only the skin but also the medial canthal tendon and the physiological canalicular pump mechanism. While the procedure is well suited for patients with primary acquired nasolacrimal duct obstruction, pathologies other than idiopathic stenosis do not qualify for this procedure. This is owing, in part, to the fact that it does not allow for full inspection of the lacrimal sac or biopsies of atypical findings to be taken19,20,22,23.
In terms of functional success, it ranges closely behind the current gold standard of external DCR with early functional success rates of 74 – 85% at one-year follow-up 10,11,12,13,14,15,16,17,18,19 for the transcanalicular approach compared to >85% for external DCR2,3,19. However, studies providing long term results are somewhat scarce. In one study, Kaynak et al. found that functional success rates of laser-assisted DCR can drop to 63% within the first year and further drop to 60% within the first two years24. In contrast, Dogan et al. found functionally successful results in up to 84% of cases over a mean follow-up time of 18.1 months17. The relatively wide range of outcomes may be due to the fact that laser-assisted DCR is not yet a standardized technique and most protocols found in literature show certain fundamental differences. These differences encompass varying laser settings and wavelengths, Teflon vs. silicon intubation, local vs. general anaesthesia and the additional use of adjuvant substances like mitomycin C (MMC) or endonasal trephination15,17,25,26,27,28. Compared to external DCR, complication rates in laser-assisted DCR are relatively low and duration of surgery as well as reconvalescence is kept to a minimum10.
In order to improve functional success rates, a number of additional steps have been proposed, adding to the mere formation of a lacrimal bypass. For one thing, in the above mentioned protocol, bicanalicular silicon intubation is included to facilitate epithelization of the bypass and prevent early scarring of the newly formed osteotomy10,11,12,13,14,15,16. This step (as either monocanalicular or bicanalicular intubation) is commonly used in a variety of protocols and techniques including external DCR2,3,19. However, the data found on this matter in current literature is conflicting and no consensus on whether patients benefit from silicon intubation in lacrimal bypass surgery has been reached to date25,26.
Furthermore, to inhibit scarring of the osteotomy, the topical application of the antimetabolite mitomycin C, known for its use in glaucoma surgery, has been proposed. Several studies investigating the alleged profit of additional topical MMC application to the bypass right after osteotomy could not show a significant advantage of this adjunctive procedure17,27,28.
The most critical step in the provided protocol is the correct formation of a sufficient osteotomy in the optimal location. When inserting the laser fiber optic, it is recommended to take the approach via the lower canaliculus as this will grant the highest maneuverability later. In a recent study of laser-assisted DC10,11, the laser fiber was advanced through the upper canaliculus in 20 of the participating patients. In three of those, correct positioning of the laser proved impossible due to prominence of the upper orbital rim, in turn leading to unfavorable positioning of the osteotomy later. Furthermore, after successful positioning of the tip and before applying energy to the lateral nasal wall, it is of paramount importance to ensure the tip has not slid back into the cannula. In one reported case10,11, retraction of the tip resulted in heating of the metal cannula, which in turn led to thermal injury that required plastic reconstruction.
It is important to note that the osteotomy created with a 300 – 400 µm diode laser fiber is markedly smaller than that of a drill in external DCR. After enlargement of the osteotomy as described above, ostium diameters of up to 5 mm can be achieved. However, the ostium diameter in external DCR ranges around 1 cm. Logically, a bigger osteotomy is less susceptible to early scarring. It is therefore recommended to aim for as big an ostium as possible while at the same time avoiding unnecessary tissue damage. It has to be noted that the induction of fibrosis as a late complication of the laser procedure is possible. However, the degree to which this happens cannot be estimated yet.
In summary, transcanalicular laser-assisted DCR, if performed as delineated above, provides good results as a viable option before invasive lacrimal surgery in cases of PANDO. Because of low complication rates and short convalescence and surgery time, patient satisfaction is high, while at the same time, functional success rates range closely behind those of external DCR.
The authors have nothing to disclose.
Deutsche Forschungsgemeinschaft (German Research Association; FOR 2240 “(Lymph)Angiogenesis And Cellular Immunity In Inflammatory Diseases Of The Eye” to LMH; HE 6743/2-1 and HE 6743/3-1 to LMH), GEROK program of the University of Cologne to KRK and LMH. Our gratitude goes to Dr. Kühner for technical support.
C1.multi | LUT | 05.0082h.1 | Endoscope camera |
HL 250 | LUT | 95.2048n | Endoscope light source |
MD-19E | ACL GmbH | 1119 | Endoscope screen |
FOX (laser) | A.R.C. Laser GmBH, Nürnberg, Germany | n/a | Diode laser |
Laser fiber | A.R.C. Laser GmBH, Nürnberg, Germany | LL13001s | Laser fiber |
Laser handpiece | A.R.C. Laser GmBH, Nürnberg, Germany | n/a | Handpiece |
Wide Collarette Monoka | Fa. FCL, Paris, France | S1.1630 | monocanalicular silicon tube |
Suction elevatorium | Storz | 474015 | For intranasal use |
Forceps (Grünwald) | Storz | 426620 | For intranasal use |
Forceps (Blakesley-Wilde) | Storz | 456502 | To grab the silicon tube |
Lacrimal canula | Storz | 81071 | Blunt cannula |
Bangerter probe cannula | Storz | 81055 | Bangerter probe cannula |
Wooden spatula | any | n/a | Wooden spatula |
Xylometazolin 0.05% eye drops | GlaxoSmithKline Consumer Healthcare | n/a | Decongestant eye drops |
Dexapos comod eye drops | Ursapharm | n/a | steroid eye drops |
Floxal eye drops | Dr. Gerhard Mann | n/a | antibiotic eye drops |