First author/year
Surgical technique
Type of DCR
MMC concentration (mg/ml)
MMC exposure time (min)
No. eyes (MMC/control)
Follow-up (months)
Silicone tube use
Success rate (MMC vs. control)
Kao et al. (1997) [25]
EX-DCR
Primary
0.2
30
15 (7/8)
6
Yes
100 % vs. 87.5 %
Yildirim et al. (2007) [37]
EX-DCR
Primary
0.2
30
40 (20/20)
12
Yes
95 % vs. 85 %
Liao et al. (2000) [4]
EX-DCR
Primary
0.2
30
88 (44/44)
10
Yes
95.5 % vs. 88.6 %
Roozitalab et al. (2004) [38]
EX-DCR
Primary
0.2
30
130 (65/65)
6
No
90.5 % vs. 92.4 %
Yalaz et al. (1999) [39]
EX-DCR
Primary
0.5/1.0
5
40 (20/20)
12–18
No
95 % vs. 90 %
Eshraghy et al. (2011) [40]
EX-DCR
Primary
0.2
5
88 (42/46)
6–15
Yes
73.8 % vs. 69.6 %
Gonzalvo et al. (2000) [26]
EX-DCR
Primary
0.2
2
17 (9/8)
6-18
No
100 % vs. 75 %
Qadir et al. (2014) [41]
EX-DCR
Primary
0.2
5
50 (25/25)
6
No
96 % vs. 80 %
Ghosh et al. (2006) [42]
EN-DCR
Primary
0.2
2
30 (15/15)
12
No
80 % vs. 86.7 %
Prasannaraj et al. (2012) [43]
EN-DCR
Primary
0.2
10
38 (17/21)
6
No
82.3 % vs. 85.7 %
Tirakunwichcha et al. (2011) [27]
EN-DCR
Primary
0.5
3
50 (26/24)
12
Yes
84.6 % vs. 79.2 %
Farahani et al. (2008) [44]
EN-DCR
Primary
0.2
3/15
92 (46/46)
12.17/12.80
Yes
91.3 % vs. 87 %
Penttilä et al. (2011) [45]
EN-DCR
Revison
0.4
5
30 (15/15)
6
No
93 % vs. 60 %
Özkiriş et al. (2012) [46]
EN-DCR
Revison
0.5
5
36 (18/18)
11.5/12.7
Yes
88.9 % vs. 55.5 %
Ragab et al. (2012) [47]
EN-DCR
Revison
0.5
10
76 (38/38)
12
Yes
82.9 % vs. 80.6 %
Dilemmas and Challenges
As described earlier, the preliminary basic science evidence, in addition to the ophthalmology experience, provides theoretic support for the use of MMC in DCR. Although the anti-proliferative effect of MMC was proven both in cell cultures and animal studies, it could not be demonstrated in clinical studies that the use of MMC following DCR influenced healing significantly. A discussion of the possible reasons behind these results is critical for improved protocol designs for future studies.
Firstly, while MMC has been used extensively in DCR surgery, the appropriate concentrations and treatment durations have not been standardized. However, wound healing in the postoperative ostium is a complex series of events mediated by several cell types and occurs over a period of 6–8 weeks [31]. Modulation of this process by MMC would require a prolonged effect that may not be possible with a single intraoperative application. Therefore, it may be worth noting that new treatment schemes should be developed, such as the use of MMC intra- and postoperatively in two separate applications as shown by Henson et al. [32]. Similarly, given the dose-dependent activity of MMC on fibroblasts demonstrated in basic science studies, clinical application would require an adequate dose for an adequate period of time. It is possible that higher doses of MMC and/or longer exposure times of MMC may be required following DCR surgery than in other applications because it may be diluted with the bleeding and irrigation that occurs postoperatively [31]. For exactly this reason, Ali et al. [33] have proposed a new technique of injecting MMC circumostially and their 1-year data in DCR are encouraging.
Secondly, the question remained unanswered whether MMC application can reduce scarring and enhance the success rate in presence of confounding effects of silicone intubation. To prevent obliteration of the intranasal lacrimal sac ostium, many surgeons prefer to insert either bi- or monocanalicular silicone tubes to stent the internal ostium. However, it has been postulated that silicone tubing itself may cause tissue granulation, predisposing the site to postoperative infection and adhesions, and canalicular lacerations, resulting in surgical failure [34]. Thus, some surgeons suggested the use of MMC to suppress fibrous proliferation and scar formation during DCR surgery along with silicone intubation. Further studies are needed to discuss whether adjunctive MMC application during silicone intubation has additional benefit over silicone intubation alone.
Lastly, despite apparently higher rates of success with no significant complications using MMC in adult lacrimal surgery, similar studies are scarce in pediatric DCR surgery. In a prospective, large case series study, Dolmetsch et al. [35] showed nonlaser endonasal DCR with MMC was a safe and successful procedure for the treatment of congenital nasolacrimal duct obstruction in children. Young patients (especially children) may present with a failure of lacrimal drainage procedures on account of an overwhelming healing response [36]. Given that the management and indications for MMC in DCR surgery are different in young patients and adults, more data are needed to draw definitive conclusions.
Conclusion
The successful use of MMC in ophthalmology and increasing use in otolaryngology have spurred interest in its use following lacrimal surgery. Although animal and clinical studies support its use in DCR surgery, overall evidence is actually lacking. The major criticism for using MMC in the nose, particularly with DCR, is the short-term effect noted. There are still many issues that remain to be addressed, including perhaps the most important one: efficacy versus safety. In the future, large randomized studies are required prior to definitive conclusions regarding the use of MMC in DCR surgery.
References
1.
Allen KM, Berlin AJ, Levine HL. Intranasal endoscopic analysis of dacrocystorhinostomy failure. Ophthal Plast Reconstr Surg. 1988;4:143–5.PubMedCrossRef
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
