Efficacy of Probing with Mitomycin-C in Adults with Primary Acquired Nasolacrimal Duct Obstruction

Introduction

Nasolacrimal duct (NLD) obstruction usually leads to annoying epiphora and sometimes conjunctivitis, low-grade infections, or recurrent acute dacryocystitis warranting a dacryocystorhinostomy (DCR). The etiology of acquired NLD obstruction is different from congenital that occurs because of persistence of the membrane at the distal opening of NLD. The majority of NLD obstruction in adults is not related to trauma, neoplasm, or systemic illness. It is postulated that inflammation of unknown cause results in occlusive fibrosis of NLD in adults, which has also been proved histopathologically. ¹

Mitomycin-c (MMC) has been extensively used in the field of ophthalmology. It is a potent inhibitor of fibroblast proliferation. ² It has been used as an adjunct in DCR through external, endonasal, and endocanalicular approach.^3–5 Authors found that its intraoperative use improves the success of the procedure and is also safe. Further, minimally invasive procedures such as probing, bicanalicular intubation, and balloon dacryoplasty have also been evaluated in adults with varying success rates.^6–9 Considering these concepts, we planned to do this study, where we analyzed the outcome of probing with or without MMC in adults with recent-onset NLD obstruction.

Methods

This was a comparative, prospective, interventional study conducted at our hospital. Ethical clearance was obtained our institution's ethics clearance committee. A total of 40 patients attending the oculoplasty clinic and general ophthalmology outdoor facility were enrolled. The patients were randomly divided into two groups of 20 each—cases were treated by probing and intraoperative MMC, and controls were treated with only probing. Patients having a history of primary epiphora of <1-year duration due to NLD block and those who gave written consent for the procedure were included. Patients with previous trauma, recurrent dacryocystitis, surgery, any other obvious cause for NLD block, or any factor leading to hyperlacrimation were excluded. Pregnant women and women who were planning to become pregnant within the next 6 months were excluded. A detailed history of the patient was taken regarding tearing, discharge, and redness in the inner canthus region. Amount of tearing was categorized according to Kraft and Crawford (1982) ¹⁰ as (−) no watering, (1+) if epiphora outdoors, (2+) if epiphora indoors with some source of irritation, (3+) if constant epiphora. In our study, complete improvement was defined as no watering; moderate improvement was defined as shifting of patient from 3+ to 1+; mild improvement was defined as shifting of patient from 3+ to 2+ or 2+ to 1+.

A single surgeon (M.K.S.) performed all the procedures. NLD block was confirmed by irrigating the lacrimal system by saline. A nasal examination was done in all patients. Probing was done under local anesthesia using 2% xylocaine with adrenaline for local infiltration (infratrochlear, nasociliary, and infraorbital blocks) and 0.5% proparacaine for topical anesthesia. The upper puncta was dilated using punctum dilator. A snuggly fitting Bowman's probe was passed to open the NLD obstruction. Irrigation with physiological saline was done to confirm the duct patency. In the study cases, this was followed by irrigation with 1 mL of MMC (0.2 mg/mL, once) with a nasal pack in place. The patient was instructed not to swallow the solution, followed by gargling with water. Irrigation of the ocular surface was done immediately with physiological saline.

In the controls, the probing was followed by irrigation with saline only. A topical steroid and antibiotic were prescribed for 2 weeks and nasal decongestant for 1 week for follow-up.

A single unmasked evaluator (M.S.B.) performed postprocedure evaluation. The patients were followed-up at 2 weeks, 4 weeks, 2 months, and 3 months. At each follow-up, the patients were questioned about watering for subjective evaluation of improvement, and syringing was done at 4 weeks, 2 months, and 3 months to confirm the duct patency. Slit-lamp examination and nasal examination were also done to look for any side effects.

Statistical Analysis

Descriptive and inferential statistics were performed using SPSS version 17 for Windows (IBM Corporation, New York). An independent sample t-test was used to compare the mean age between the 2 groups. The Friedman's test was used to compare the 2 groups with regard to the various categories of subjective improvement in epiphora after probing. The Mc Nemar's test was used to compare the patency of the NLD at various time points between the groups during the follow-up.

Results

A total of 40 patients with acquired NLD block were recruited in the study and were randomly divided into two groups of 20 patients each. In the study, the age ranged 26–60 years with a mean of 39.7 years and in the controls, 22–57 years with a mean of 35.35 years (P value 0.345). There was equal distribution of men and women. Table 1 shows the comparison of complete, moderate, and mild subjective improvement at each follow-up with their P-values. Although the comparison was not statistically significant at any follow-ups, complete and overall improvement was better in the cases. A steady decline in the success rate of the procedure was observed in both cases and controls over the 3-month period. At the end of 3 months, complete and overall improvement was found in 15% and 65% of the cases and 0% and 40% in controls, respectively. On evaluating the patency (Table 2) of the lacrimal system by syringing at 1 month, 2 months, and 3 months, we found patency in 55%, 35%, and 30% of cases and 15%, 10%, and 10% of controls, respectively (P values 0.008, 0.127, and 0.235). The patency was significantly better in cases at 1-month follow-up, but this difference became insignificant at subsequent follow-ups indicating closure of NLD. No significant side effects of MMC were observed in the cases.

Discussion

Nasolacrimal probing has proved efficacious for children with congenital NLD obstruction with a success rate as high as 98% in simple obstruction probably, because the NLD is normal in this group of patients. ¹¹ Most of the lacrimal surgeons have reported a decline in success with increase in age, which is explainable on the basis of longstanding blockage, which leads to stagnation and inflammation, hence fibrosis of NLD resulting in failure. ¹² A study on histopathology of NLD in adults with obstruction found the presence of active chronic inflammation along the entire NLD in early cases; intermediate cases had focal areas of fibrosis, while late cases showed fibrous obliteration of the entire duct. ¹ Another study on histopathology of lacrimal sacs found inflammatory changes in 94% and bony inflammation in 14% of the patients. ¹³ In contrary to these studies, Kashkouli et al. showed normal sac pathology in acquired cases of primary NLD blocks. ¹⁴

According to a recent review on clinical outcomes of external DCR surgery, the success ranged between 65% and 100%, ¹⁵ depending on the surgeon's experience, but still studies are ongoing on the role of less-invasive procedures to cure this entity in adults because of the obvious advantages. Probing is a simple, easy, cost effective, quick, and a minimally invasive procedure, so its utility in adults has been studied by a few authors and found that the success rate of patients' satisfaction (watering subjectively improved) after undergoing the procedure was 82%. ⁶ Other less-invasive procedures such as bicanalicular silicone intubation of the lacrimal system and balloon dacryoplasty have also been investigated. In one study, complete success of bicanalicular silicone intubation in adults was reported as 47%. ⁷ In another study on silicone intubation, with or without balloon dacryoplasty in adults with partial blocks found complete improvement in epiphora in 52% and 57% cases, respectively. ⁸ In an effort to improve the success of these procedures, Tsai et al. in their study used adjunctive MMC as an antifibrotic agent to achieve good long-term results. This was a noncomparative study in which 1 mL of MMC in concentration of 0.2 mg/mL was syringed three times into the duct. Authors treated 36 eyes of the 32 patients and reported complete absence of watering in 25% of yes, moderate improvement in 47%, and mild improvement in 11% of cases at 9-month follow-up. Probing was repeated during the follow-up period in recurrent cases; however, we did not repeat the probing in our recurrent cases to avoid more trauma and less chances of gain in subjective and objective improvement. Single probing resulted in a patency rate of 89%. No side effects of MMC were observed in their series. ⁹ The present study was a comparative study on probing with or without MMC (1 mL of 0.2 mg/mL, once), and we found at the end of 3 months that complete and overall improvement in epiphora was 15% and 65% in cases and 0% and 40% in controls, respectively. The patency at the end of study was 30% and 10% in cases and controls, respectively. The patency was significantly better in cases where MMC was used, and at 1-month follow-up, this difference became insignificant at subsequent follow-ups, indicating closure of NLD. No significant side effects of MMC were observed in the present study.

Specifically, there were no instances of ocular inflammation, abnormal change of nasal mucosa, or systemic side effect. Thus, it seems reasonable to suggest that irrigation with a controlled volume of MMC at a low concentration (0.2 mg/mL) is safe in a single application of this type.

In this study, overall subjective improvement of the epiphora was reported in 65% with the use of MMC. Furthermore, a single probing with MMC resulted in a patency rate of 30%. In patients with NLD obstruction, for a duration of less than one year, MMC can thus be used as initial procedure with good success rate with regard to subjective improvement in the epiphora. We believe that this procedure can be a good alternative to the conventional DCR surgery. Limitations of this study were small sample size, and postprocedure evaluation was done by unmasked evaluator. Future study with larger sample size, double blind, and longer duration of follow-up is needed to further evaluate the efficacy of using MMC during probing and syringing in adult NLD block.