Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT00784992 |
| Other study ID # |
H08-02025 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
Phase 4
|
| First received |
November 4, 2008 |
| Last updated |
March 1, 2017 |
| Start date |
November 2008 |
| Est. completion date |
June 2, 2016 |
Study information
| Verified date |
March 2017 |
| Source |
University of British Columbia |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Aim of study is to investigate whether the use of silicone tubes in endonasal DCR surgery
increases the success rate and / or complication rate compared to surgery without tubes.
Description:
Dacryocystorhinostomy (DCR) is the treatment of choice for epiphora due to nasolacrimal duct
obstruction. A passage is created between the lacrimal sac and nasal cavity by removing the
layers of bone and mucosa between them. It can be performed via an external (transcutaneous)
or endonasal route with equivalent success rates.[1] In order to prevent restenosis of the
ostium, silicone tubes are often used to maintain the patency of the newly-created fistula.
The tubes are removed between 6 weeks and 3 months post-operatively.
Problems associated with tubes include granuloma formation with secondary infection or
adhesions, canalicular lacerations, allergic reaction to the silastic, and discomfort.
There are a number of reports of DCR surgery without tubes which demonstrate an equivalent
success rate compared with surgery using tubes; however, these studies have been
non-randomised, retrospective reviews.[2-6] The only prospective, randomised controlled
study[7] had only 42 participants and did not state at which point during the surgery the
randomisation was revealed; unless the allocation occurs after the ostium has been completed
there is the risk of bias since the surgeon may (consciously or inadvertently) create a
larger ostium in cases where no tubes are to be used.
The purpose of this study is to perform a prospective, randomised controlled study to assess
whether the use of tubes affect the long-term success of DCR.
Hypothesis Silicone tubing does not improve success rate of endonasal DCR surgery.
Justification There is a dearth of evidence in the literature from well-conducted studies on
the merits of tubes versus no tubes in DCR surgery. Since there are several potential
problems with tubes outlined above, and since performing surgery with tubes adds to the cost
and duration of surgery, it would benefit patients and healthcare providers to know whether
they increase DCR success rate.
The standard surgical technique for endonasal DCR has been described by the principle
investigator.[1] The identical procedure would be performed in both groups with the
exception that half the patients would have tubes inserted, and half would not.
Objectives To assess functional and anatomical success rates of endonasal DCR surgery with
and without silicone tubes.
Research Method Prospective, randomised, controlled, interventional trial.
Statistical analysis The primary end point will be functional success, determined by
patient-reported symptoms. This will be assessed a minimum of six months post-operatively.
In patients with tubes these will be removed at 3 months post-operatively.
The operation will be considered successful if the patient is free of symptoms of a watering
eye. It will be considered partially successful if the patient has noticeable improvement
but still may experience tearing under certain situations. The operation will be deemed a
failure if the patient continues to have symptoms that are no better or worse than
pre-operatively.
The secondary end point will be anatomical success, as measured by patency of nasolacrimal
irrigation at 6 months post-operatively. In patients with tubes these will be removed at 3
months post-operatively. The operation will be considered successful if there is free flow
on irrigation with no reflux. It will be considered partially successful if the nasolacrimal
duct is patent but there is more than 50% reflux as assessed by an experienced oculoplastic
surgeon. It will be considered a failure if there is more than 50% reflux.
The secondary end point will be anatomical success, as measured by patency of nasolacrimal
irrigation at 6 months post-operatively.
Statistical analysis planned From a previous study by the PI[1] (and also from numerous
other studies in the ophthalmic literature) the baseline success rate for endonasal DCR with
tubes is 90%. The current trial is a non-inferiority study, ie to demonstrate that surgery
without tubes is not inferior to surgery with tubes.
In order to demonstrate non-inferiority, the recommended approach is to pre-specify a margin
of non-inferiority in the protocol. After study completion, a two-sided 95% confidence
interval for the true difference between the two agents will be constructed.[8]
Planned sample size A sample size of 200 (100 participants in each arm of the trial) is
expected to give a 95% confidence interval of width of approximately 0.15 ie +/- 7.5% around
the estimated difference in success rates.
References
1. Dolman PJ. Comparison of external dacryocystorhinostomy with nonlaser endonasal
dacryocystorhinostomy. Ophthalmology. 2003 Jan;110(1):78-84
2. Smirnov G, Tuomilehto H, Teräsvirta M, Nuutinen J, Seppä J. Silicone tubing after
endoscopic dacryocystorhinostomy: is it necessary? Am J Rhinol. 2006
Nov-Dec;20(6):600-2
3. Mortimore S, Banhegy GY, Lancaster JL, Karkanevatos A. Endoscopic dacryocystorhinostomy
without silicone stenting. J R Coll Surg Edinb. 1999 Dec;44(6):371-3
4. Kashkouli MB, Parvaresh M, Modarreszadeh M, Hashemi M, Beigi B. Factors affecting the
success of external dacryocystorhinostomy. Orbit. 2003 Dec;22(4):247-55
5. Beigi B, Westlake W, Chang B, Marsh C, Jacob J, Chatfield J. Dacryocystorhinostomy in
south west England. Eye. 1998;12 ( Pt 3a):358-62.
6. Unlü HH, Oztürk F, Mutlu C, Ilker SS, Tarhan S. Endoscopic dacryocystorhinostomy
without stents. Auris Nasus Larynx. 2000 Jan;27(1):65-71
7. Smirnov G, Tuomilehto H, Teräsvirta M, Nuutinen J, Seppä J. Silicone tubing is not
necessary after primary endoscopic dacryocystorhinostomy: A prospective randomized
study. Am J Rhinol 22, 214-217, 2008
8. http://www.emea.europa.eu/pdfs/human/ewp/215899en.pdf
