**Class II Special Controls Guidance Document: Endolymphatic Shunt Tube
with Valve; Draft Guidance for Industry and FDA**

***Draft Guidance -- Not for Implementation***

**This guidance document is being distributed for comment purposes
only.**

**Draft released for comment on \[release date as stated in FR
Notice\]**

### **This document supersedes the Guidance for the Technical Content of a Premarket Approval Application for an Endolymphatic Shunt Tube with Valve issued on April 1, 1990**

![](media/image1.png){width="0.9631944444444445in"
height="1.0763888888888888in"}

**U.S. Department of Health and Human Services**

**Food and Drug Administration**

**Center for Devices and Radiological Health**

**Ear, Nose, and Throat Devices Branch**

**Division of Ophthalmic and Ear, Nose, and Throat Devices**

**Office of Device Evaluation**

**Preface**

**Public Comment:**

For 90 days following the date of publication in the Federal Register of
the notice announcing the availability of this guidance, comments and
suggestions regarding this document should be submitted to the Docket
No. assigned to that notice, Dockets Management Branch, Division of
Management Systems and Policy, Office of Human Resources and Management
Services, Food and Drug Administration, 5630 Fishers Lane, Room 1061,
(HFA-305), Rockville, MD 20852.

**Additional Copies**

Additional copies are available from the Internet at:
<http://www.fda.gov/cdrh/%5Bspecific> address\], or CDRH
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#### Class II Special Controls Guidance Document: Endolymphatic Shunt Tube with Valve; Draft Guidance for Industry and FDA

***This document is intended to provide guidance. It represents the
Agency's current thinking on this topic. It does not create or confer
any rights for or on any person and does not operate to bind the Food
and Drug Administration (FDA) or the public. An alternative approach may
be used if such approach satisfies the requirements of the applicable
statute and regulations.***

##### Background

On November 6, 1986, FDA issued a final rule classifying the
endolymphatic shunt tube with valve into class III (premarket approval).
On July 27, 1990, FDA received a petition from Hood Laboratories
requesting a change in the classification of the endolymphatic shunt
tube with valve from class III to class II. The Ear, Nose and Throat
Devices Panel met on June 11, 1992 and recommended that the generic
endolymphatic shunt tube with valve be reclassified from class III into
class II. FDA disagreed with the Panel's recommendation and found that
the petition contained insufficient valid scientific evidence to
determine that the special controls described in section 513 (a) (B) of
the act, in addition to the general controls applicable to all devices,
would provide reasonable assurance of the device's safety and
effectiveness for its intended use. Accordingly, the FEDERAL REGISTER of
December 9, 1996, (61 FR 64909), FDA published a notice denying Hood
Laboratories' petition to reclassify the endolymphatic shunt tube with
valve from class III to class II.

On May 27, 1997, Hood Laboratories submitted a second petition in
accordance with section 513(e) of the act and 21 CFR 960.130 (a) (3),
based on new information. The petitioner requested reclassification of
the endolymphatic shunt tube with valve from class III to class II. In
accordance with section 513(e) of the act, 21 CFR 860.130, and based on
new information submitted or otherwise available to the agency with
respect to the device, FDA is proposing to classify this class II when
the device is intended to be implanted in the inner ear to relieve the
symptoms of vertigo and hearing loss due to endolymphatic hydrops of
Meniere's Disease. Consistent with the act and the regulations, FDA did
not refer the petition to the Panel for its recommendation on the
requested change in classification. This document is the special
controls guidance for the endolymphatic shunt tube with valve.

FDA has determined that special controls, when combined with the general
controls, are sufficient to provide reasonable assurance of the safety
and effectiveness of the endolymphatic shunt tube with valve. Thus, a
manufacturer who intends to market a device of this generic type will
need to (1) conform with the general controls of the Food, Drug &
Cosmetic Act, including the premarket notification (510(k)) requirements
described in 21 CFR 807.81, and (2) address the specific risks to health
associated with the endolymphatic shunt tube with valve and receive a
"substantial equivalence" determination from FDA prior to marketing the
device.

This guidance document outlines suggested measures that when followed
will generally address the risks associated with the endolymphatic shunt
tube with valve and lead to a timely 510(k) review and clearance. For
the specific content requirements of a 510(k) submission, preparers of
submissions should refer to 21 CFR 807.87 and other agency documents on
this topic.

##### Scope 

FDA identifies the generic endolymphatic shunt tube with valve as an
Ear, Nose and Throat device classified under 21 CFR 874.3850, product
code KLZ. It is intended to be implanted in the inner ear to relieve the
symptoms of vertigo and hearing loss due to endolymphatic hydrops of
Meniere's disease.

This generic type of device consists of a pressure-limiting valve
associated with a tube intended to be implanted in the inner ear to
relieve the symptoms of vertigo and hearing loss due to endolymphatic
hydrops of Meniere's disease. The device directs excess endolymph from
the distended end of the endolymphatic system into the mastoid cavity
where resorption occurs. The function of the pressure-limiting inner ear
valve is to maintain the physiologically normal endolymphatic pressure
and to ensure a unidirectional flow of endolymph.

The Hood Laboratories' endolymphatic shunt tube with valve is the only
device of its type in commercial distribution in the United States. It
consists of a silicone catheter connected to a silicone tube that is
inside a molded, silicone body. The inside silicone tube has a slit
valve at one end that allows the endolymph to exit. The silicone tube is
inserted into the end of the endolymphatic sac to allow the endolymph to
flow through the valve and into the mastoid cavity via the tail-like
portion of the molded silicone body.

##### 

##### Risks to Health

> FDA has identified the following risks to health associated with the
> use of the endolymphatic shunt tube with valve: (1) a build up of
> fluid pressure in the inner ear due to a clogged or inoperative valve;
> and, (2) revision surgery to correct a defective valve, including
> infection.

####### Special Controls

In addition to general controls, FDA believes that the special controls
identified below are appropriate to address the potential risks to
health described for this device:

1.  Labeling;

2.  Valve Performance;

3.  Materials Specifications;

4.  Biocompatibility Testing; and

5.  Sterility Testing

# Labeling

## Based on the scientific data available, FDA believes that labeling should restrict the use of the device and that the indication for use of the device should include the following statement: "The device is intended for use in patients who have been diagnosed with Meniere's disease and for whom more conservative methods of treatment, including medical treatment and less complex surgical procedures such as sac surgery without shunt, may not be considered appropriate by the attending physician." {#based-on-the-scientific-data-available-fda-believes-that-labeling-should-restrict-the-use-of-the-device-and-that-the-indication-for-use-of-the-device-should-include-the-following-statement-the-device-is-intended-for-use-in-patients-who-have-been-diagnosed-with-menieres-disease-and-for-whom-more-conservative-methods-of-treatment-including-medical-treatment-and-less-complex-surgical-procedures-such-as-sac-surgery-without-shunt-may-not-be-considered-appropriate-by-the-attending-physician. .unnumbered}

Because there is a lack of objective and scientific data to establish
that the device operates as a one-way valve *in vivo* to regulate
endolymphatic pressure, FDA believes that the labeling should also
include this statement:

The effectiveness of the shunt with valve to maintain physiologically
normal pressure has not been established by well controlled, randomized
clinical studies. Observational data, including case reports suggests
that the shunt with valve may preserve hearing and reduce or eliminate
symptoms of Meniere's disease in some patients who require surgical
intervention.

# Valve Performance

There continues to be a lack of valid scientific evidence to determine
the effectiveness of the shunt with valve in maintaining a
physiologically normal endolymphatic pressure and defining the normal
pressure within the endolymphatic sac. The observational data described
above was obtained using the Hood Laboratories' device. That device is
characterized by a valve opening pressure of 4.3 to 6.0 inches of water.
Because it is the only legally marketed device, and there is no other
information available, valve performance data would be needed to
demonstrate equivalency to any currently marketed devices. Each unit
should be tested, i.e., 100 percent sample testing, prior to
implantation to ensure that the specification is met.

# Materials Specification

The currently marketed valve body is constructed of silicone rubber
elastomer and silicone rubber adhesive. The capillary tubing in the
valved shunt is made of polyether block amide (PEBA), which is a
biomaterial with chemical stability in a physiological environment. PEBA
addresses the concern of long-term functioning and integrity of the
capillary tubing material Supramid™, which was used in the earlier Hood
device.

Future valve shunts should have similar dimensional, flexibility,
strength, and durability characteristics as the currently marketed valve
shunt. Any biocompatible material used in the construction of future
valved shunts that is not identical to the predicate should have the
tensile strength, durometer, elongation, and hardness characteristics
equivalent to the Hood device. However, if the materials are not
identical to the predicate device, additional performance or clinical
data, may be necessary.

### **Biocompatibility Testing**

Adherence to the biocompatibility testing procedures presented in the
Office of Device Evaluation (ODE) Blue Book Memorandum G95-1, entitled
"Use of International Standard ISO-10993-1",
<http://www.fda.gov/cdrh/g951.html>, can control the risk of adverse
tissue reaction by having the manufacturer demonstrate that the patient
contacting materials of the endolymphatic shunt tube with valve are safe
for long-term implantation.

# Sterility Testing

Adherence to the procedures in the guidance document entitled, "510(k)
Sterility Review Guidance," 1/2/90 (K90-1)
<http://www.fda.gov/cdrh/k90-1.html> can help control the risk of
infection by guarding against the implantation of an unsterile device.

Manufacturers who reference any recognized standards as part of their
510(k) submission should provide statements regarding conformance or
"Declarations of Conformity" under the Guidance on the Recognition and
Use of Consensus Standards <http://www.fda.gov/cdrh/modact/k982.html>
FDA Modernization Act of 1997. Because statements afford greater
flexibility for device developers than "Declarations of Conformity,"
submitters of 510(k)s should consider using guidances and standards in
this manner.

FDA believes that the conformance with the above referenced guidance
documents and recognized standards, in addition to the general controls,
will be sufficient to control the identified risks to health associated
with use of the endolymphatic shunt tube with valve.