Topical mitomycin C as a postoperative adjunct to endonasal dacryocystorhinostomy in patients with anatomical endonasal variants

Antimetabolites as an adjunct to dacryocystorhinostomy for nasolacrimal duct obstruction

BACKGROUND

Nasolacrimal duct obstruction (NLDO) is a condition that results in the overflow of tears (epiphora) or infection of the nasolacrimal sac (dacryocystitis). The etiology of acquired NLDO is multifactorial and is not fully understood. Dacryocystorhinostomy (DCR) is the surgical correction of NLDO, which aims to establish a new drainage pathway between the lacrimal sac and the nose. The success of DCR is variable; the most common cause of failure is fibrosis and stenosis of the surgical ostium. Antimetabolites such as mitomycin-C (MMC) and 5-fluorouracil (5-FU) have been shown to be safe and effective in reducing fibrosis and improving clinical outcomes in other ophthalmic surgery settings (e.g. glaucoma and cornea surgery). Application of antimetabolites at the time of DCR has been studied, but the utility of these treatments remains uncertain.

OBJECTIVES

Primary objective: To determine if adjuvant treatment with antimetabolites improves functional success in the setting of DCR compared to DCR alone. Secondary objectives: To determine if anatomic success of DCR is increased with the use of antimetabolites, and if the surgical ostium is larger in participants treated with antimetabolites.

SEARCH METHODS

We searched the Cochrane Register for Controlled Trials (CENTRAL) (which contains the Cochrane Eye and Vision Trials Register) (2019, Issue 9), Ovid MEDLINE, Embase.com, PubMed, LILACS (Latin American and Caribbean Health Sciences Literature database), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic searches. We last searched the electronic databases on 6 September 2019.

SELECTION CRITERIA

We only included randomized controlled trials. Eligible studies were those that compared the administration of antimetabolites of any dose and concentration versus placebo or another active treatment in participants with NLDO undergoing primary DCR and reoperation. We only included studies that had enrolled adults 18 years or older. We also included studies that used silicone intubation as part of the DCR procedure.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently screened the search results, assessed risk of bias, and extracted data from the included studies using an electronic data collection form.

MAIN RESULTS

We included 31 studies in the review, of which 23 (1309 participants) provided data relating to our primary and secondary outcomes. Many of the 23 studies evaluated functional success, while others also assessed our secondary outcomes of anatomic success or ostium size, or both. Study characteristics Participant characteristics varied across studies, with the age of participants ranging from 30 to 70 years. Participants were predominantly women. These demographics correspond to those most frequently affected by nasolacrimal duct obstruction. Almost all of the studies utilized MMC as the antimetabolite, with only one using 5-FU. We assessed most trials as at unclear risk of bias for most domains. Conflicts of interest were not frequently reported, although the antimetabolites used are generic medications, and studies were not likely to be conducted for financial interest. Findings Twenty studies provided data on the primary outcome of functional success, of which 7 (356 participants) provided data at 6 months and 14 (909 participants) provided data beyond 6 months. At six months, the results showed no evidence of effect of antimetabolite on functional success (risk ratio (RR) 1.12, 95% confidence interval (CI) 0.98 to 1.29; low-certainty evidence). Beyond six months, the results favored the antimetabolite group (RR 1.15, 95% CI 1.07 to 1.25; moderate-certainty evidence). Fourteen studies reported data on the secondary outcome of anatomic success, of which 4 (306 participants) reported data at 6 months and 12 (831 participants) provided data beyond 6 months. Results at six months showed no evidence of effect of antimetabolite on anatomic success (RR 1.02, 95% CI 0.95 to 1.11; low-certainty evidence). Beyond six months, participants in the antimetabolite group were more likely to achieve anatomic success than those receiving DCR alone (RR 1.09, 95% CI 1.04 to 1.15; moderate-certainty evidence). At six months and beyond six months follow-up, two studies reported mean change in ostium size. We did not conduct meta-analysis for the various follow-up periods due to clinical, methodological, and statistical heterogeneity. However, point estimates from these studies at six months consistently favored participants in the antimetabolite group (low-certainty evidence). Beyond six months, while point estimates from one study favored participants in the antimetabolite group, estimates from another study showed no evidence of a difference between the two groups. The certainty of evidence at both time points was low. Adverse events Adverse events were rare. One study reported that one participant in the MMC group experienced delayed wound healing. Other studies reported no significant adverse events related to the application of antimetabolites.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that application of antimetabolites at the time of DCR increases functional and anatomic success of DCR when patients are followed for more than six months after surgery, but no evidence of a difference at six months, low-certainty of evidence. There is low-certainty evidence that combining antimetabolite with DCR increases the size of the lacrimal ostium at six months. However, beyond six months, the evidence remain uncertain. Adverse effects of the application of antimetabolites were minimal.

[Mitomycin C after endoscopic endonasal dacryocystorhinostomy]

Mitomycin-C (MMC) is the most frequently used agent for prevention of excessive scarring at the osteotomy site after endoscopic endonasal dacryocystorhinostomy (EEDCR), which, however, being applied during the final stage of the surgery, shows questionable effectiveness.

AIM

to evaluate the effectiveness of a new administration route of mitomycin C in EEDCR.

MATERIAL AND METHODS

The study included 86 patients (95 cases) in the age range of 62.3±9 years with primary acquired nasolacrimal duct obstruction. All patients underwent P.J. Wormald modification of EEDCR and were further divided into 2 groups. In group 1, MMC was injected into the nasal cavity and lacrimal sac mucosa, while in group 2 it was applied locally according to the standard procedure. To measure tissue concentrations of MMC, mucosal biopsies were taken in patients of Group 1. Systemic absorption of MMC was studied through blood samples in both groups. Clinical efficacy was assessed in 14±5 months after surgery.

RESULTS

immediately after injection, the average tissue concentration of mitomicyn C in patients of Group 1, was 390±10 µg/g and 30 minutes later - 120±20 µg/g. No mitomycin C was found in Day 1 tissue samples and in any of the blood samples. Positive clinical results were reported in 97.9% of cases from Group 1 and in 87.2% of cases from Group 2.

CONCLUSION

The method of injecting MMC during the final stage of EEDCR has proved clinically effective and safe and can be recommended for use in clinical practice.

Indian Survey on Practice Patterns of Lacrimal and Eyelid Disorders (iSUPPLE) Report 2: Mitomycin-C and Lacrimal Stents in Dacryocystorhinostomy

PURPOSE

The aim of the study was to assess practice patterns on the use of intraoperative Mitomycin-C (MMC) and lacrimal stents (intubation) in dacryocystorhinostomy (DCR) for nasolacrimal duct obstruction (NLDO) among oculoplastic surgeons in India. The survey was aimed at obtaining data on the duration of stent placement and specifics regarding MMC usage namely, concentration and duration of application.

METHODS

A survey that included questions on the management of lacrimal disorders was sent in April 2015 to members of the Oculoplastic Association of India, through an email communication. The results were tabulated and analyzed.

RESULTS

External DCR is the preferred surgery of choice to treat NLDO for most oculoplastic surgeons (86%) surveyed. A majority (58%) of the respondents do not place stents during DCR routinely in their practice. Lesser experienced oculoplastic surgeons (<10 years of experience) when compared with more experienced surgeons were more likely to place stents routinely in their DCRs (59% versus 19%; P = 0.0002). Of the special situations that the respondents would consider stent placement, the most common scenarios were the presence of coexisting canalicular pathology followed by cases of previously failed DCRs. The preferred duration for stent removal was 3 months (48%). Intraoperative MMC was used routinely by only 36% of the respondents. The most common condition where they would consider intraoperative MMC was previously failed DCRs. Three minutes (25%) and 0.2 mg/mL (30%) were the preferred duration of application and concentration of MMC, respectively.

CONCLUSIONS

External DCR is the most preferred surgery for NLDO; in comparison, endoscopic DCR enjoys less popularity as the surgical procedure of choice in NLDO. Adjunctive procedures, namely intraoperative MMC and stenting of the lacrimal passages, are not routinely performed; however, previously failed DCRs are common indications when the respondents may use MMC and/or lacrimal stents. Three months is the preferred duration for stent removal. The trends regarding the concentration of MMC and the application show considerable variation, underscoring the need for evidence-based guidelines to assist oculoplastic surgeons.

Mitomycin-C in dacryocystorhinostomy: From experimentation to implementation and the road ahead: A review

Dacryocystorhinostomy (DCR) is the procedure of choice in patients with epiphora due to primary acquired nasolacrimal duct obstruction. The evolution of surgical tools, fiber-optic endoscopes, effective anesthesia techniques, and the adjunct use of antimetabolites intraoperatively; namely mitomycin-C (MMC) have significantly contributed to the advancement of DCR surgery. MMC is a systemic chemotherapeutic agent derived from Streptomyces caespitosus that inhibits the synthesis of DNA, cellular RNA, and protein by inhibiting the synthesis of collagen by fibroblasts. Even the cellular changes in the human nasal mucosal fibroblasts induced by MMC at an ultrastructural level have been documented. There, however, seems to be a lack of consensus regarding MMC: The dosage, the route of delivery/application, the time of exposure and subsequently what role each of these variables plays in the final outcome of the surgery. In this review, an attempt is made to objectively examine all the evidence regarding the role of MMC in DCR. MMC appears to improve the success rate of DCR.

Electron microscopic features of nasal mucosa treated with topical and circumostial injection of mitomycin C: implications in dacryocystorhinostomy

PURPOSE

To evaluate the ultrastructural effects of topical and circumostial injection of mitomycin C (COS-MMC) on nasal mucosa and compare them with the controls. The study also aimed at classifying the subcellular effects in detail.

METHODS

The nasal mucosa of 6 patients were subjected to 0.02% of mitomycin C for 3 minutes (3 patients) and 0.02% COS-MMC (3 patients) as per standard protocol, during endoscopic dacryocystorhinostomy. Normal nasal mucosa from untreated areas (2 each from topical and COS-MMC groups) were taken as controls after harvesting the treated areas. Full thickness tissues (5 mm × 5 mm) were collected for transmission electron microscopy, and ultrastructural effects were evaluated.

RESULTS

Both topical and COS-MMC showed significant and distinct ultrastructural changes involving the epithelial, glandular, vascular, and fibrocollagenous tissues compared with the controls. There were profound changes within fibroblasts with intracellular edema, pleomorphic and vesicular mitochondria, dilated smooth and rough endoplasmic reticulum, and chromatin condensation. In addition, COS-MMC samples showed subepithelial hypocellularity with limited disorganization of structure. The changes in both the MMC groups were restricted to treated areas only.

CONCLUSIONS

Both topical and COS-MMC show profound changes in nasal mucosa with more marked changes in COS-MMC group. These changes being limited in nature may help in enhancing the success of dacryocystorhinostomy by preventing cicatricial changes of the ostium, especially in high-risk cases such as revision and post-traumatic dacryocystorhinostomy.

Mitomycin C in dacryocystorhinostomy: the search for the right concentration and duration--a fundamental study on human nasal mucosa fibroblasts

PURPOSE

To establish primary cultures of human nasal mucosal fibroblasts (HNMFs) and to test the effect of varying concentrations of mitomycin C (MMC) and treatment durations on cellular proliferation and viability of the fibroblasts.

DESIGN

Laboratory investigation.

METHODS

Nasal mucosa harvested from patients undergoing a dacryocystorhinostomy was used to establish primary cultures by explant culture method. Cells were expanded and frozen at every passage, and passage 3 cells were used for further experiments. The cells were then treated with different concentrations of mitomycin C (0.1-0.5 mg/ml) for different time periods (3, 5, and 10 minutes). Cell viability was checked by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Cellular proliferation index was determined with bromodeoxyuridine immunostaining. Apoptotic index was measured using annexin A5 affinity assay, propidium iodide staining, and 4',6-diamidino-2-phenylindole counterstaining. The actin cytoskeletons of fibroblasts were studied using phalloidin staining.

RESULTS

The doubling time of cultured HNMFs is approximately 24 hours. Similarly, 0.4 mg/ml beyond 5 minutes and 0.5 mg/ml concentration at all time points were lethal and caused extensive cell death when compared with controls. A concentration of 0.2 mg/ml for 3 minutes of exposure prevented cell proliferation of HNMF cells by inducing cell cycle arrest, without causing extensive apoptosis.

CONCLUSIONS

The minimum effective concentration appears to be 0.2 mg/ml for 3 minutes. This in vitro study could be the starting point for further clinical and histopathologic studies to validate its clinical usefulness.

Factors associated with outcome of endonasal dacryocystorhinostomy

PURPOSE

To identify factors associated with outcome of endonasal dacryocystorhinostomy.

METHODS

One hundred thirty-four cases of endonasal dacryocystorhinostomy in 111 patients performed for primary acquired nasolacrimal duct obstruction by a single surgeon between March 12, 2002 and November 10, 2008 were included in a retrospective, noncomparative case series. Variables assessed during the surgery included intranasal view, difficulty of bone removal, size of the lacrimal sac, presence of lacrimal sac stones, orbital fat prolapse and degree of bleeding. Successful outcome was defined as patency to lacrimal irrigation at final follow up.

RESULTS

One hundred twenty-one of the 134 cases (90%) were patent to irrigation at final follow up (mean 8.8 ± 8.6 months). A small lacrimal sac opening intraoperatively was associated with higher risk of failure (odds ratio [95% confidence interval] of 5.7 [1.6, 20] [p = 0.0072]). Orbital fat prolapse had a trend toward higher risk of failure that approached statistical significance (odds ratio [95% confidence interval] of 5.3 [0.87, 32] [p = 0.0698]). A narrow intranasal view, difficult bony opening, lacrimal sac stones, and bleeding were not associated with outcome.

CONCLUSIONS

A small lacrimal sac opening intraoperatively was associated with failure of endonasal dacryocystorhinostomy.