Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01766232 |
| Other study ID # |
IRB 07-926 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
May 13, 2011 |
| Last updated |
February 17, 2015 |
| Start date |
April 2009 |
| Est. completion date |
February 2015 |
Study information
| Verified date |
February 2015 |
| Source |
The Cleveland Clinic |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
United States: Institutional Review Board |
| Study type |
Observational
|
Clinical Trial Summary
Epiphora, or uncontrolled tearing of the eyes, represents a common presenting complaint of
patients seen by ophthalmologists. Epiphora may be due to non-obstructive causes, such as
tear hypersecretion or functional tear pump failure, or obstructive causes. Functional tear
pump failure may result from malposition of the eyelids, such as an abnormal out-turning
(ectropion) or in-turning (entropion) of the eyelid.
Currently methods to diagnose partial nasolacrimal duct obstruction are purely qualitative
in nature. Our research goal is to quantitatively measure the pressure generated during
conventional probing and irrigation (P&I), and to measure the resistance to irrigation of
the nasolacrimal drainage system.
The investigators will measure the pressure generated during conventional P&I using a
disposable in-line pressure transducer. In addition, the investigators will use a syringe
pump to deliver a constant flow rate of saline through a nasolacrimal cannula and measure
the steady state irrigation pressure using the in-line transducer and digital pressure
monitor. Resistance can be directly calculated from the known flow rate and pressure
measurements.
The investigators will compare both the pressure generated during P&I and the lacrimal
drainage resistance between patients with lacrimal drainage obstruction and controls
patients with no obstruction (functional tear pump failure) as determined by clinical exam.
Clinical applications for measuring lacrimal drainage resistance include quantifying partial
nasolacrimal duct obstruction, guiding the choice of surgical procedure, and determining the
success of lacrimal drainage procedures.
Description:
Lacrimal Drainage Resistance
I. Introduction
This proposal describes our plan to study the resistance of the lacrimal drainage system
during irrigation.
II. Research Aims
A. Specific Aims
1. To quantitatively measure the resistance of the lacrimal drainage system during
irrigation.
2. To determine differences in lacrimal drainage resistance between patients with
obstructed tear drainage systems and patients with functional tear pump failure.
3. To measure the pressure generated during traditional probing and irrigation of the
lacrimal drainage system.
B. Background and Significance
Epiphora, or uncontrolled tearing of the eyes, represents a common presenting complaint of
patients seen by ophthalmologists. Epiphora may be due to non-obstructive causes, such as
tear hypersecretion or functional tear pump failure, or obstructive causes. Functional tear
pump failure may result from malposition of the eyelids, such as an abnormal out-turning
(ectropion) or in-turning (entropion) of the eyelid.
Tears normally drain from the eye through two small holes, called puncta, one located in the
upper eyelid and one in the lower eyelid, and then through two channels, called canaliculi,
that empty into the lacrimal sac. Tears drain from the lacrimal sac through the bony
nasolacrimal duct into the nasal cavity. Obstruction may occur at any level of the system,
and may be partial or complete.[1] The focus of this study is acquired (as opposed to
congenital), nasolacrimal duct obstruction.
The normal work-up for evaluation of nasolacrimal duct obstruction includes multiple
clinical tests to evaluate the patency of the drainage system, including the fluorescein dye
disappearance test, primary and secondary Jones dye tests, and canalicular probing and
irrigation (P&I). While complete obstruction is relatively easily determined, partial
obstruction is more difficult. Each of the available tests is qualitative in nature and is
unable to determine the degree of partial obstruction. [1, 2] Current management options for
the treatment of partial nasolacrimal duct obstruction include repeated canalicular probing
and irrigation, balloon catheter dilation with placement of silicone stents, and
dacryocystorhinostomy (DCR) surgery. Repeated probing and irrigation may be performed in the
clinic without anesthesia, but has a low rate of improved symptoms. Balloon catheter
dilation with stent placement is typically performed under general anesthesia, requires no
incisions, and has a success rate between 60-73%.[3, 4]. DCR surgery, also typically
performed under general anesthesia, surgically bypasses the nasolacrimal duct by removing a
window of bone and anastomosing the lacrimal sac to the nasal cavity. The success rate of
DCR is over 95%.[1, 5] There are two previously published methods to measure lacrimal
drainage resistance. In 1991, Stanley and Masri described a device to measure resistance
with a hand-held instrument connected to a personal computer.[6] They reported values from
13 normal controls, but did not test the device in patients with tearing. In 1995, Tucker et
al. reported a laboratory-based device that measured the resistance to fluid flow in the
lacrimal drainage system.[2] They measured resistance in healthy controls, in patients after
successful DCR, and in one tearing patient.
The investigators will measure the pressure generated during conventional P&I using a
disposable in-line pressure transducer. In addition, the investigators will use a syringe
pump to deliver a constant flow rate of saline through a nasolacrimal cannula and measure
the steady state irrigation pressure using the in-line transducer and digital pressure
monitor. Resistance can be directly calculated from the known flow rate and pressure
measurements.
Clinical applications for measuring lacrimal drainage resistance include quantifying partial
nasolacrimal duct obstruction, guiding the choice of surgical procedure, and determining the
success of lacrimal drainage procedures.
III. Study Design and Methods
Study Design:
The investigators plan to measure lacrimal drainage resistance in consented patients
undergoing evaluation and management of epiphora who require traditional probing and
irrigation. In addition to the traditional probing and irrigation of the nasolacrimal
system, the investigators will measure the lacrimal drainage resistance using our study
equipment.
Accrual Goals and Recruitment Period:
The accrual goal for this study is 40 eligible patients.
The final clinical diagnosis of lacrimal drainage obstruction versus functional tear pump
failure will be based upon the investigators clinical findings and standard probing and
irrigation results.
Patient Entry:
Patient eligibility will be determined by the study's principal investigator or
co-investigators and as described in this protocol. The investigator will interview eligible
patients and explain in detail the purpose of the study. Those patients who agree to
participate will have the pressure measured during conventional P&I and lacrimal drainage
resistance measured in addition to the normal clinical work-up. For those patients who agree
to participate in the study, signing the informed consent constitutes study entry.
Time Requirement:
The investigators estimate that it will take 2 months for patient accrual and measurements.
Follow-Up:
There are no required follow-up visits.
Measurement of outcomes:
Two measurements will be obtained from each patient. First, the investigators will record
the pressure generated during traditional probing and irrigation using a disposable in-line
pressure transducer. Second, the investigators will measure the pressure generated using a
syringe pump to deliver a constant flow rate. The investigators will then directly calculate
the resistance to irrigation from the pressure and flow rate.
IV. Study Procedure: The Intervention
Probing and irrigation (P&I) of the lacrimal drainage system is a standard component of the
evaluation of tearing patients. During this procedure, a nasolacrimal cannula is inserted
into the canaliculus and saline solution is irrigated through the system. The investigators
will measure the pressure generated during P&I using a disposable in-line pressure
transducer. In addition to conventional P&I, consented patients would undergo a second
irrigation procedure using our measuring equipment. In order to eliminate any bias due to
the order of testing, half of the patients will undergo conventional P&I first, and half
will undergo the experimental P&I first. During the experimental P&I, a syringe pump will
deliver a constant flow rate of saline through a nasolacrimal cannula. The investigators
will measure the steady state irrigation pressure using an in-line transducer and digital
pressure monitor. Resistance will be calculated from the known flow rate and pressure
measurements. The investigators will obtain three measurements from each patient.
The syringe pump is designed to prevent backflow of saline, and in addition the disposable
portion of the pressure transducer exposed to the saline will be changed between each
patient. The syringe pump has an automatic safety cut-off if the line is occluded.
V. Interpretation of Data
The investigators will record the pressure generated during conventional P&I and the average
pressure generated during steady-state irrigation. Resistance will be directly calculated
from the average pressure measurement. The investigators will compare both the pressure
generated during P&I and the lacrimal drainage resistance between patients with lacrimal
drainage obstruction and controls patients with no obstruction (functional tear pump
failure) as determined by clinical exam. The investigators will summarize data in terms of
means and standard deviations. The null hypothesis, that there are no differences between
groups, will be tested by a two-sample Students t-test with p < .05 for rejection of the
null. For lacrimal drainage resistance, a sample size of 17 patients per group gives a power
of 0.91 to detect a difference as small as 20 mmHg*sec/ml. The power measurements are based
upon the work of Tucker et al., who measured an average resistance of 49.5 +/- 17.0
mmHg*sec/ml in normal controls, and a single measurement of 212 mmHg*sec/ml in a patient
with symptomatic tearing.[2] Technical complications will be noted and described. All
patient information will be a part of the permanent medical record and will be no different
from the information documented in standard nasolacrimal irrigation.
VI. Consent Procedure
In addition to a verbal discussion describing the study, including the risks and benefits,
the investigators will provide patients undergoing evaluation for epiphora including
conventional probing and irrigation with a formal consent form, and the investigators will
provide a copy of this consent for personal reference. The proposed consent form is
attached.
VII. Adverse Events
The anticipated adverse events of conventional probing and irrigation are anxiety and
discomfort during the procedure, foreign body sensation for 12-24 hours following the
procedure, and irrigant or dye on clothing. Anticipated serious adverse events of
conventional probing and irrigation include dacryocystitis and damage to the lacrimal
drainage system including punctal rupture. The incremental risks of the experimental probing
and irrigation relate to the pump device. Because the pump device has an automatic safety
cut-off and pushes fluid at a very low flow rate (0.09 mL/s) the investigators believe that
the incremental risks are very low. Stanley and Masri reported one case of punctal rupture
using their experimental setup.[6] The investigators believe this is unlikely to occur in
our experiment because the investigators are using a standard nasolacrimal cannula to
irrigate, and the investigators are using a much lower flow rate (0.09 mL/s versus 0.25
mL/s).
All adverse events will be documented in the data collection forms and brought to the
attention of the patient and his or her family as soon as possible after their occurrence.
Patients are provided with contact information for the principle investigator as well as the
Institutional Review Board in the consent form, and an on-call ophthalmologist is always
available for emergent care after hours. On-call ophthalmologists will have direct pager
access to the investigators and will notify them immediately of any adverse events
encountered in study patients. Serious and unanticipated adverse events will be promptly
reported to the Institutional Review Board by the principle investigator.
VII. Cited Literature
1. Mills, D.M. and D.R. Meyer, Acquired nasolacrimal duct obstruction. Otolaryngol Clin
North Am, 2006. 39(5): p. 979-99, vii.
2. Tucker, S.M., et al., Measurement of the resistance to fluid flow within the lacrimal
outflow system. Ophthalmology, 1995. 102(11): p. 1639-45.
3. Kuchar, A. and F.J. Steinkogler, Antegrade balloon dilatation of nasolacrimal duct
obstruction in adults. Br J Ophthalmol, 2001. 85(2): p. 200-4.
4. Perry, J.D., et al., Balloon catheter dilation for treatment of adults with partial
nasolacrimal duct obstruction: a preliminary report. Am J Ophthalmol, 1998. 126(6): p.
811-6.
5. Tsirbas, A., G. Davis, and P.J. Wormald, Mechanical endonasal dacryocystorhinostomy
versus external dacryocystorhinostomy. Ophthal Plast Reconstr Surg, 2004. 20(1): p.
50-6.
6. Stanley, C.F. and F.A. Masri, Instrument to test patency of lacrimal drainage system. J
Clin Eng, 1991. 16(1): p. 57-60.
