Randomized Comparison of Nasolacrimal Cryoplasty versus Plastic Lacrimal Stenting in the Management of Epiphora in Adults

Randomized Comparison of Nasolacrimal Cryoplasty versus Plastic Lacrimal Stenting in the Management of Epiphora in Adults Carlos Lanciego, MD, Sofía Navarro, Javier Velasco, Miguel Perea, Rafael Cuena-Boy, MD, and Lorenzo García-García, MD

PURPOSE: To evaluate the efficacy of plastic polyurethane stents compared with nasolacrimal cryoplasty in the management of epiphora in adults. MATERIALS AND METHODS: Patients (N ⴝ 37; mean age, 64 years; range, 34 – 86 y; six men, 31 women) with severe epiphora with partial/complete obstruction of the nasolacrimal system were randomized to have a plastic stent inserted (n ⴝ 19) or to undergo balloon dilation cryoplasty (n ⴝ 18). Both procedures were conducted on an outpatient basis. Patency was assessed with Kaplan-Meier curves. RESULTS: Initial technical success rate and immediate resolution of epiphora was complete in all cases. At 6 months of follow-up, outcomes were already significantly different between the treatment groups and hence the study was discontinued. Plastic stent placement achieved a primary patency rate of 59.6% at 6 months, compared with 12.4% in the cryoplasty group (P < .0004). Multivariate analysis indicated that other measured variables (sex, age, etiology, previous treatment, and the interventional radiologist’s expertise) had no significant effect on the outcomes (P > .05). CONCLUSIONS: Initial success was good in both treatment groups, with nasolacrimal plastic stent placement achieving a level of primary patency superior to the cryoplasty procedure for the relief of epiphora on short-term follow-up. However, long-term outcome evaluation is needed before stent placement can be recommended as an alternative to more established surgical procedures. J Vasc Interv Radiol 2009; 20:1588 –1596 Abbreviations:

DCP ⫽ dacryocystoplasty, DCR ⫽ dacryocystorhinostomy

EPIPHORA (ie, abnormal increase of tearing of one or both eyes) secondary to lacrimal obstruction is a relatively common problem and represents 3% of clinical consultations in ophthalmology (1,2). Although there are many causes of obstruction of lacrimal outflow, most cases are caused by idiopathic inFrom the Departments of Interventional Radiology (C.L., J.V., L.G.G.), Ophthalmology (S.N., M.P.), and Statistical Investigation (R.C.B.), Hospital “Virgen de la Salud,” Complejo Hospitalario de Toledo, Avenida de Barber 30, 45004 Toledo, Spain. Received March 3, 2009; final revision received August 13, 2009; accepted August 17, 2009. Address correspondence to C.L.; E-mail: [email protected] None of the authors have identified a conflict of interest. © SIR, 2009 DOI: 10.1016/j.jvir.2009.08.026

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flammation and scarring of the nasolacrimal system. Acquired obstructions occur in adulthood and sometimes are not related to trauma, neoplasm, or systemic disease. Involutionary stenosis is probably the most common cause of nasolacrimal obstruction in older individuals, with women being twice as likely to be affected as men (3). The pathology of the obstruction remains uncertain, but compression of the duct by inflammatory infiltrates and edema precede the development of the clinical presentation of chronic dacryocystitis and is accompanied by pain and discomfort (1,4). Its continuance tends to provoke chronic lacrimal irritation, conjunctivitis, and sometimes eczematous eyelids (4,5). Although it is not a threat to vision, it is a troublesome problem

for patients, and can be psychologically and socially debilitating (6). Two interventional radiologic procedures to treat this condition have found favor in the past decade: (i) dacryocystoplasty (DCP) with conventional balloon dilation and (ii) the currently favored technique of polyurethane stent placement in the site of blockage. As a result of its modest success rates, DCP has been restricted in its application to single lesions and to partial obstructions that are short and below the sac-duct junction. DCP is of less use in complete obstructions of the lacrimal duct (3–7). The alternative of stent insertion has gained credence among ophthalmologists and interventional radiologists. The technique is not yet as well established as the traditional options such as open surgery or endoscopic dacryocys-

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Table 1 Indications and Contraindications for Stent Placement or Cryoplasty Indications 1. Epiphora grade III/IV (on Munk scale) 2. Obstruction located in the sac, nasolacrimal duct, or in the sac/duct junction 3. Patients with epiphora do not wish to undergo surgery or are unsuitable 4. Patients with severe epiphora before surgery for cataract removal 5. Medium- or large-size sac defined on dacryocystography Contraindications 1. Epiphora grade I/II (on Munk scale) 2. Age ⬍18 y 3. Obstruction located at the level of the canaliculus or common canaliculus 4. Suspicion of tumor in the lacrimal sac 5. Presence of active infection (acute dacryocystitis) 6. Congenital dacryostenosis 7. Restricted size of lacrimal sac* * Relative contraindication as the technique is merely more difficult to apply. In the present study there were no cases that presented with a sac that was too small.

torhinostomy (DCR). However, published data suggest that the stent placement procedure with the Song plastic stent is a safe, easy, and effective way to treat epiphora (8 –12). Recently, for economic reasons, the manufacturer of the Song stent withdrew the device from the market. The only commercially available device is the plastic stent developed by Wilhelm (Tearleader stent; InterV/PBN Medicals, Stenløse, Denmark). There appears to be a possible outcome improvement versus conventional DCP when a variation on balloon cryoplasty is employed (Polar-Cath peripheral balloon; Boston Scientific, Natick, Massachusetts). Hence, our group decided to conduct a randomized study in collaboration with the ophthalmologists of our hospital to compare the outcomes of the two nonsurgical minimally invasive therapies for the treatment of epiphora.

Eligibility and Patient Recruitment All patients who presented to our ophthalmology clinic for treatment of severe epiphora based on Munk score (13) were consecutively recruited into the study. Essentially, the grades of severe epiphora (grades III/IV) indicate that the patient experiences frequent episodes of tearing (5–10 times a day for grade III; ⬎10 times a day for grade IV). The inclusion and exclusion criteria are presented in Table 1. Assignment of the patients to treatment groups was randomized and stratified according to the site of obstruction (sac– duct union, sac, and duct) by means of a stratified random permuted blocks scheme. Sealed opaque envelopes were used to conceal the randomization sequence. Interventions for Comparison

MATERIALS AND METHODS

One of the groups of patients underwent nasolacrimal balloon dilation (iie, cryoplasty) and the other had plastic stents inserted.

Design of the Study

Outcomes

The study is a randomized, singlecenter clinical trial with two parallel intervention groups and with follow-up evaluation of intervention success by a third party blinded with respect to patient group assignment. The study protocol was approved by our institutional ethics committee and all patients provided written informed consent to participate in the trial.

The principal response variable was primary patency. This was measured as duration of the absence of epiphora together with patency of the lacrimal system, ie, from the time of the intervention until the time of a new intervention (ie, withdrawal of the stent, new dilation, or placement of a new stent) required to maintain permeability. Patients who were lost to follow-up were censured from the study, as were those who

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showed continued primary patency at the end of the study period. We measured the technical success (ie, correct positioning of the stent or DCP balloon and lacrimal system patency confirmed on dacryocystography immediately after the procedure) as well as the complications arising from the procedures. Causes of technical failure were recorded, including inability to place the stent or DCP balloon, pass through the stenosis with the guide wire, or withdraw the device via the nares. Clinical outcomes during the period of follow-up were evaluated by ophthalmologists who were blinded with respect to treatment group assignment. Evaluations were at 1 week, 1 month, 6 months, and 1 year of follow-up (the date initially set for the end of the project). Patient Preparation After being selected as a candidate for the technique of lacrimal stent placement or balloon cryoplasty, patients were provided with detailed information by the radiologist who was scheduled to perform the intervention. The information explained the procedure, the complications and benefits expected, the success according to the literature, and the possibility of epiphora recurrence resulting from recurrent nasolacrimal duct stenosis and its management. Finally, the patient was informed that the procedure was in its consolidation phase and that long-term validation was not yet available. This informed consent was oral as well as written. Procedures were performed in the interventional radiology suite, with the patient placed in supine decubitus position with the fluoroscope Carm in lateral position. The working zone (palpebral area and nasogenian area) is cleaned thoroughly with diluted iodinated povidone and local anesthesia is applied to the nasal mucosa with a pledget of cotton impregnated with a solution of tetracycline chlorohydrate antibiotic plus adrenalin at 1:1,000 dilution (1% topical anesthesia; Braun, Melsungen, Germany). Two drops of local anesthetic agent are placed in the eye (tetracaine 0.1% and oxybuprocaine 0.4%; Colircusi double anesthetic) for greater patient comfort. All the procedures are performed with moder-

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Figure 1. Step-by-step nasolacrimal plastic stent insertion technique. (a) Materials from a Tearleader stent set. (b) Introduction of the guide wire via the superior lacrimal punctum. (c) Withdrawal of the guide wire via the naris with the hook. (d) Advancement of the plastic cannula through the guide wire. (e) Introduction of he whole system (with the plastic stent and the carrier) in a retrograde manner. (f) Lateral projection dacryocystography shows a fluoroscopic view of a correctly placed stent. (g) Contrast medium is used to demonstrate patency of the stent. (Available in color online at www.jvir.org.)

ate sedation (grade 2/3 on the Ramsay scale) provided by an anesthetist in the operating room during the whole procedure. The Tearleader stent set designed by Wilhelm (InterV/PBN Medicals) was used for stent placement. The Polar-Cath peripheral balloon (Boston Scientific) was used for cryoplasty. A preliminary dacryocystography is performed with use of iodinated contrast medium (Iopamiro; Bracco-Lab Rovi, Milano, Italy) to completely fill the sac so as to identify the best canaliculus (the su-

perior or inferior, and which is most directly in line with the sac) into which to introduce the guide wire. Stent Placement Technique The plastic stent insertion technique is well established and well described in the literature by Wilhelm et al (14). Briefly, a 0.018-inch ball-tipped guide wire is introduced into the nasolacrimal duct system and gently advanced until the inferior meatus of the nasal cavity is reached. Here the specially designed

tapered dacryocystography catheter is advanced over the guide wire until it exits from the nostril. The guide wire is then withdrawn and a new flexible angled nitinol guide wire is introduced via the catheter into the nasolacrimal duct system. Under fluoroscopic guidance, the guide wire is gently pushed forward to the external nares (in the majority of occasions it was pulled out of the external nares with a hook). For our present purposes, the hook used was from an original Song kit, but an “inhouse” device is equally acceptable.

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Figure 2. Main steps in the technique of balloon cryoplasty. (a) Materials from the Polar-Cath peripheral balloon set. (b) Detail of the cryoplasty balloon. (c) Introduction of the balloon in a retrograde manner. (d) Fluoroscopic view of the correctly placed cryoplasty balloon. (e) The balloon has automatically inflated. (f) Complete inflation of the balloon within the lacrimonasal system. (g) Lateral projection dacryocystography shows a good restoration of lacrimal flow (with the aid of contrast medium after the intervention). (Available in color online at www.jvir.org.)

From the distal position, the stent is threaded directly on to the guide wire, followed by a stent pusher. The next step is to either (i) advance the stent and stent pusher in a retrograde manner along the guide wire until contact is made with the dacryocystography catheter at the level of the lacrimal sac or (ii) en-

sure that the extreme end of the stent is correctly positioned with help of fluoroscopic guidance. The stent pusher is then endonasally removed and the guide wire is withdrawn via the lacrimal punctum. The nasolacrimal system is irrigated with physiologic saline solution (gently, to avoid dislodging the stent) and initial

dacryocystography is performed to confirm the correct stent positioning and to demonstrate initial patency. Cryoplasty Balloon Technique Dacryocryoplasty requires a similar technique, ie, introducing the balloon catheter (3.5 mm in diameter ⫻ 4 mm in

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43 patients initially

6 excluded - 5 canaliculus obstruction - 1 non-obstructive epiphora

37 fulfilled the inclusion criteria

18 patients Group 1: cryoplasty

Figure 3.

19 patients Group 2: plastic stent

Patient flow through the study.

length) in a retrograde manner up to the level of the obstruction. Subsequently, the balloon is connected to a device to inflate the balloon once with nitrous oxide, automatically and in a controlled manner. The desired temperature of the balloon is also controlled in the process. Both procedures are described in Figures 1 and 2.

A dacryocystogram was obtained only in the event of recurrence of epiphora as a result of stent failure or based on suspicion of lacrimal restenosis after previous cryoplasty. As such, the flushing with saline solution is an integral part of assessing the success of the procedure and measuring overall outcome. Design and Statistical Analyses

Postprocedural and Follow-up Care To ensure patency, a final check-up with saline solution irrigation was made at the end of the procedure in the interventional radiology suite before the patient was discharged from the hospital. The assessment was performed within 10 minutes of concluding the procedure. On recovery, the patient was asked to score his or her pain level on a visual analog scale of 0 –10. Immediately after the stent placement or cryoplasty procedure, a prophylactic regimen of ocular topical antibiotic collyrium is administered (tobramycin; three drops every 8 hours for 7 days). Neither oral antibiotics nor steroids were used. A close follow-up is the key to the success of this treatment. The nasolacrimal system is maintained patent only if regular care (by means of saline solution irrigation) is provided, preferably by the ophthalmologist on the team involved in the study. Our protocol included clinical check-ups (including irrigation) in the first week, at 1, 3, and 6 months, and every 6 months thereafter. Follow-up care by the ophthalmologist consists of irrigation with physiologic saline solution of both lacrimal puncta. The flushing is performed once or twice with 2 mL saline solution, which is chilled by some investigators so that the patient notes the sensation at the back of the throat.

The initial calculation of maximum sample size that was necessary was based on the premise of primary patency rates of 60% at 1 year in the stent group and less than 40% in the cryoplasty group (one sided test with ␣ of 0.05 and ␤ of 0.2). The patient sample was calculated as 76 patients per group. The rates of patency assumed in each group were not based on totally reliable information from the literature. In the cryoplasty group, the impression we had was that the rate of patency would be much lower than envisaged. Hence, and to avoid having to treat more patients with the less effective technique than was necessary, the guidelines for the protocol involved yearly intermediate analysis after the procedure. In addition, and as a special measure of safety, it was decided to perform an analysis of the data immediately if there was evidence that there would need to be approximately 25% more subjects included into the study than had been previously envisaged, with at least 50% of them having experienced the loss of primary patency. Although the protocol did not include any concrete proposals on the circumstances that would necessitate intermediate analyses, the trial was prematurely concluded in view of the clear advantages of stent placement versus balloon cryoplasty when there were only 37 patients in the study.

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The statistical analyses were performed with SPSS software (version 11.0; SPSS, Chicago, Illinois) for Windows (Microsoft, Redmond, Washington). The baseline characteristics of the groups are presented as the means and SDs or ranges and percentages, depending on the type of variable or measurement. The comparison among groups with respect to time to primary loss of patency was performed with use of Kaplan-Meier survival analysis method and the log-rank test. A multivariate analysis was performed on primary patency with the model of proportional risks (ie, Cox regression). The hazard ratio and the 95% CI were calculated for both techniques, adjusted for various independent variables (eg, age, sex, etiology, radiologist expertise, previous treatment) and stratified for the level of obstruction. Proportionality of hazards assumption was checked with the use of diagnostic plots based on Schoenfeld residual plots against time for each covariable, and by the comparison of cumulative survival versus time graphs between the groups generated by the covariable values. The protocol was explicit that comparisons must be not only on a perprotocol basis but also by intent to treat and should take into account consistency between types of analyses required to draw a conclusion. Comparisons between treatment groups of cumulative survival versus time were performed as a function of the covariable values. Comparisons between the treatment groups (separately and in combination) were made not only on a per-protocol basis but also by intent to treat.

RESULTS The study commenced in October 2007. By June 2008 there had been 43 patients with severe epiphora referred for treatment to our interventional unit by the ophthalmologist. The patients were reevaluated clinically and with dacryocystography in our unit to confirm whether the patients fulfilled the selection criteria for the study (Fig 3). Of the 43 consecutive patients seen, six were not eligible, five because of obstruction of the lacrimal canaliculus and one because of nonobstructive epiphora (ie, functional). The 37 eligible patients provided consent to participate in the

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Table 2 Patient Characteristics Characteristic

Group 1: Cryoplasty (n ⫽ 18)

Group 2: Plastic Stent (n ⫽ 19)

61 ⫾ 13.4 34–82

67 ⫾ 12.9 38–86

4 (22.2) 14 (77.8)

2 (11.5) 17 (89.5)

10 (55.6) 8 (44.4)

9 (47.4) 10 (52.6)

12 (66.7) 4 (22.2)

10 (52.6) 7 (36.8)

14 (77.8) 4 (32.2)

11 (57.9) 8 (42.1)

10 (55.6) 8 (44.4)

11 (57.9) 8 (42.1)

13 (72.2) 2 (11.1) 3 (16.7)

14 (73.7) 1 (5.7) 4 (21.1)

Age (y) Mean ⫾ SD Range Sex Male Female Lacrimal side Left Right Etiology Idiopathic Chronic dacryocystitis Previous treatments None Previous stents Radiologist expertise Very expert (⬎500 interventions) Competent (50–100 interventions) Stenosis site Sac/duct junction Sac Duct

Note.—Values in parentheses are percentages.

Figure 4. Median and mean patency duration in the groups treated with stent placement and cryoplasty. (Available in color online at www.jvir.org.)

trial and were randomly assigned to the treatment groups: cryoplasty (n ⫽ 18) and plastic stent placement (n ⫽ 19). The flow of patients is presented in Figure 3. All patients rigorously complied with the protocol of clinical fol-

low-up in the ophthalmology clinic except one patient who was lost to follow-up in the third month. To date, all the procedures have been concluded with technical and clinical success. There were 18 patients who had

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loss of primary patency during followup. This fulfilled one of the conditions envisaged in the protocol requiring an intermediate statistical analyses (ie, 24.3% of the subjects intended for recruitment with 48.6% of them already experiencing an event). In view of this high percentage of loss of primary patency and before the 1-year follow-up had been reached by any of the patients, it was clear that the efficacy of one or both interventions was less than originally envisaged and, for patient safety concerns, the first interim analysis was conducted, as per protocol. The characteristics of the patients are summarized in Table 2. At the time of the intermediate analyses, 54% of the patients had been followed up for approximately 2 months and the remaining 46% for more than 2 months but less than 8 months. There were 13 adverse outcomes in the cryoplasty group and five in the stent group. Figure 4 shows that, at 6 months of follow-up in the stent placement group, there was a primary patency rate of 59.2% ⫾ 15.1%, whereas that of the cold balloon dilation (ie, cryoplasty) group was 12.5% ⫾ 10.6% (P ⫽ .00004). Table 3 summarizes the results of the Cox regression analysis stratifying for the level of obstruction. After adjustment for the rest of the measured variables, the difference between groups was maintained, ie, the hazard ratio of primary permeability loss with cryoplasty relative to stent placement was 9.79 (95% CI, 1.76 – 54.46). The hazard ratios for the rest of the variables studied (sex, age, epiphora etiology, previous treatment with stent vs no treatment and radiologist expertise in lacrimal intervention) were not significantly different from unity (Table 3). In view of not only the considerable difference in primary patency between the two groups (46.7% in favor of the stent), but also the level of significance (P ⫽ .0004), which was much lower than the protocol-set level of P ⬍ .05, and having applied whatever corrections were envisaged in the interim analyses, the decision was made to end the study prematurely. Side Effects and Complications All the procedures (in both groups) were concluded with success (technical and initial clinical success rates of

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Table 3 Primary Patency According to a Cox Proportional-Hazards Model (Multivariate Cox Survival Analysis)* Comparison

HR

95% CI

Female vs male Chronic dacryocystitis vs idiopathic Previous stent vs none Experienced vs inexperienced radiologist Age (y) Plastic stent vs cryoplasty

0.463 1.953 0.733 1.637 1.008 9.790

0.052–4.115 0.449–8.490 0.068–7.959 0.449–5.976 0.955–1.064 1.760–54.456

* Sex, cause of epiphora, previous lacrimal system treatment, age, and radiologist experience in lacrimal interventions had no influence on the outcomes in the present series of patients, whereas the type of intervention was related to a significant decrease in mortality hazard.

Figure 5. Dacryocystography in lateral projection in patients referred from the ophthalmology clinic because of epiphora recurrence caused by restenosis 1 month after cryoplasty (a) and by stent obstruction (b).

100%). Only two cases of slight epistaxis were registered, and these were selflimiting (one in each treatment group). The epistaxis occurred within a few minutes after intervention in both cases. The mean time taken to complete the procedure was 12 minutes for stent placement and 18 minutes for cryoplasty. On recovery, the patient was asked to score the level of pain after the intervention on a visual analog scale between 0 and 10, and 32 of 37 cases were evaluable for response. The mean score was 2–3 points (range, 0 – 6) which is the equivalent of slight pain/discomfort, despite the analgesia and sedation employed in all cases. During follow-up, two patients (both in the plastic stent group) sought a clinical visit with the ophthalmologist because of palpebral edema in the first week after the intervention. This re-

quired no further treatment other than local symptom treatment. The most frequent complication, and that which determined the end of the primary patency, was recurrent obstruction of the lacrimal system (by obstruction and/or migration of the stent in the stent group and by restenosis of the nasolacrimal system in the cryoplasty group). The result was a recurrence of epiphora confirmed on dacryocystography by the radiologist (Fig 5).

DISCUSSION Classically, obstruction of the lacrimal system has been treated surgically, and the techniques have improved considerably over time. Currently, external DCR continues to be the technique of choice. However, the technique requires general anesthesia and often leaves a

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permanent facial scar. In addition, failure rates are still approximately 6%– 21% (10,15). External DCR is associated with success rates of 79%–90%, but possible complications include periorbital emphysema, hemorrhage, infection, cerebrospinal fluid leakage, partial or complete obstruction of the fistulous tract, and growth of mucosal tissue over the nasolacrimal opening. In the search for alternatives that are less invasive than external DCR, a new surgical approach, termed endonasal laser DCR, was proposed by Massaro et al (16). It involves the use of a sophisticated argon laser to minimize the main bleeding complications associated with conventional DCR. The procedure does not produce an external scar, conserves the function of the lacrimal pump, and does not cause lesions to the medial canthus tendon. However, external DCR still appears superior to endonasal laser DCR (17) in terms of outcomes and of patient preference. The recent trend toward other endonasal surgical solutions (not necessarily with lasers) has become more attractive because of better outcomes and patient tolerance of the procedures (18 –21). In the mid-1990s, less invasive nonsurgical therapies for lacrimal obstruction were developed. These included balloon DCP (3,13,22,23) and its endoscopic variants (24), as well as the insertion of expandable stents (metallic or plastic) under fluoroscopic guidance (25–27). The nonsurgical procedures offer advantages over their invasive surgical counterparts, which include avoidance of general anesthesia, simplicity and safety of the procedure, no facial scar, reduced bleeding-related problems, and avoidance of substantial anatomic alterations. Also, the procedures are well tolerated by the patients and, being performed on an outpatient basis, are very cost effective (28). Lee et al (29), in 2001, presented a large series of patients treated with DCP. The different factors that could influence primary patency were evaluated. The authors concluded that, although they had achieved an initial success of approximately 93%, the final long-term patency was only approximately 63%. Also, this success was achieved only in the more favorable cases such as those of partial stenosis at the level of the lacrimal duct. The authors were unable to recommend the stents for use in the less favorable cases

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such as those of complete obstruction of the sac and lacrimal duct. Other studies (30 –32) have indicated that partial obstruction may be a prognostic factor for the success of DCP. Janssen et al (30) reported a primary patency rate of 70% for acquired nasolacrimal obstruction, with the highest success rate in partial obstructions. Berkefeld et al (31) reported 1-year primary patency rates of 73% in partial obstructions and only 50% in complete obstructions. Ilgit et al (32) reported primary patency rates of 100% in partial obstruction and 59% in complete obstructions. These results were achieved with narrow patient selection (ie, focal lesions, partial junction obstructions, and short-distance distal lesions) and restricted clinical indications for the technique. Since the Song stent was first described by Song et al (15), several publications have described its use (8,11– 13,25,33–36). The numbers of patients treated by Song and Kang (8) have now reached more than 600, with a follow-up of 5 years (37). The primary patency rates of 73%–93% obtained during the first year of follow-up made the technique very attractive to practitioners. However, the rates of primary patency diminish progressively with time. In general, the levels of primary patency are reasonable in the short and medium term but very modest in the long term (ie, ⬎5 years). For example, Song et al (37) reported a 5-year primary patency rate of only 19%, whereas the data of Lanciego et al (12) showed a 59.6% patency rate. The rates of recurrent stent obstruction are similar in most studies, at approximately 30% (8,12,33), but the study of Paul et al (38) showed a rate of obstruction of nearly 60%. Secondary patency is modest, albeit consistent at approximately 32% in the medium and long term. These data have caused a reduction in the original optimism regarding the technique. Different groups have tried to develop new ways of improving these outcomes by focusing on improving DCP with the use of mitomycin-C (39) as an alternative to stent placement in cases of complete obstruction. Results showed a 55% cumulative patency rate at a mean of 19 months of follow-up and clear superiority of DCP with mitomycin-C versus DCP without mitomycin-C, which offered only a 20% patency in the same follow-up period. Other groups have tried to im-

Lanciego et al prove the outcomes of Song stent use with a simple in-house modification such as cutting off the proximal end of the polyurethane stent and thereby introducing an open configuration in the form of a cone. The primary patency rate with this modification reached 85% in 195 stents in 183 lacrimal systems in 170 patients followed up for a mean of 18 months (40). The primary patency rate at more than 1 year was almost 84%, the rate of stent blockage was 15%, and the secondary patency rate was 67% at a mean follow-up of 15 months (40). Recently, the same group (41) published an update of their patient series with the modified stent. In 330 stents placed in 285 patients, a primary patency rate of 78% was achieved by year 3 of follow-up. Finally, as the third option, other groups such as that of Wilhelm et al (14) have focused on developing different types of lacrimal stents. In recent years, there have been several preliminary studies published as abstracts in which plastic stents in the shape of an italic “S” have been used (42). The results have been modest. As highlighted in the abstract by Ferrer-Puchol et al (43), the 1and 2-year cumulative patency rates were approximately 51% and 31%, respectively. However, it is difficult to compare data from these publications because of the limited information contained in such abstracts. Some authors have even proposed returning to the use of metal stents. However, the poor results have not favored their reintroduction (44). The manufacturer of the Song stent recently decided (since 2006) to withdraw the stent from the market because of economic reasons. The only alternative currently available to the interventional radiologist for minimally invasive nonsurgical treatment of obstructive epiphora is to use the only plastic stent available commercially (Tearleader stent) The paucity of data in the literature, together with the option of reintroducing DCP but with some improvements (in our case, dilation with a chilled balloon), prompted us to design the present study to compare the two noninvasive options available in our hospital since 2007. In conclusion, the results of the present study have been slightly encouraging. The Wilhelm plastic stent had better outcomes than DCP (by an

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approximate 4:1 ratio). The 60% primary patency rates at 6 and 7 months in the stent group are much lower than those reported in the majority of case series of the Song stent (ie, 1-year patency rate ⬎80%). This is the threshold level suggested by Becker et al (45) as being the minimum requirement for stents to be considered valid alternatives to the surgical procedures currently considered as reference. Hence, practitioners need a new stent to be made available commercially (hopefully based on improvements to the original Song stent) so patients can be offered a viable alternative to surgery of the lacrimal system. Stent placement, because of its simplicity, safety, and reproducibility, is a viable alternative provided that the long-term outcomes can be improved. There is a considerable lack of studies comparing the efficacy and complications at more than 5 years of follow-up of nasolacrimal stents, external DCR, and the endonasal DCR solutions. Such studies are vital before decisions can be made as to which is the procedure of choice for any particular patient requiring resolution of obstructive epiphora. References 1. Linberg JV, McCormick SA. Primary acquired nasolacrimal duct obstruction: a clinicopathologic report and biopsy technique. Ophthalmology 1986; 93: 1055–1063. 2. Traquair HM. Chronic dacryocystitis: its causation and treatment. Arch Ophthalmol 1941; 26:165–180. 3. Lee JM, Song HY, Han YM, et al. Balloon dacryocystoplasty: results in the treatment of complete and partial obstructions of the nasolacrimal system. Radiology 1994; 192:503–508. 4. Duke-Elder S. System of ophthalmology: In: Duke-Elder S, ed. The ocular adnexa, vol 13. London: Henry Kimpton, 1974; 675– 693. 5. Song HY, Ahn HS, Park CK, Kwon SH, Kim CS, Choi KC. Complete obstruction of the nasolacrimal system. Part II: treatment with expandable metallic stents. Radiology 1993; 186:372–376. 6. Tsai CC, Kau HC, Kao SC, Hsu WM, Liu JH. Efficacy of probing nasolacrimal duct with adjunctive mitomycin-C for epiphora in adults. Ophthalmology 2002; 1:172–174. 7. Yazici Z, Yazici B, Parlak M, Erturk H, Savei G. Treatment of obstructive epiphora in adults by balloon dacryocystoplasty. Br J Ophthalmol 1999; 83:692– 696.

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