Third Eye Retroscope Randomized Clinical Evaluation

Colorectal cancer is the second most common cause of cancer death in the U.S.
In 2007, an estimated 158,000 new cases of colorectal cancer were diagnosed in
the U.S. and over 50,000 people died of the disease. Colorectal cancer
generally causes no symptoms until it is far advanced. However, it can usually
be successfully treated if it is detected early enough.
Several methods have been used for screening for colorectal cancer, including
fecal occult blood testing, barium enema, flexible sigmoidoscopy, colonoscopy,
and more recently, CT colonography (also known as virtual colonoscopy).
Colonoscopy is currently regarded as the *gold standard* for detection of
polyps and cancers in the colon. However, a growing number of studies have
documented that significant numbers of lesions are missed during routine
colonoscopy.

Avantis Medical Systems has designed a retrograde auxiliary imaging device that
is designed to allow visualization of *hidden areas* during colonoscopy by
providing an additional, retrograde view that complements the antegrade view of
the colonoscope. The retrograde view assists the endoscopist in visualizing the
proximal aspect of haustral folds and rectal valves, as well as the areas
behind flexures and the ileocecal valve. With this additional point-of-view,
the endoscopist may be able to detect lesions that can be missed by the
forward-viewing colonoscope.
In bench testing with anatomical models containing simulated polyps, use of the
Third Eye Retroscope auxiliary imaging device was found to result in a markedly
improved detection rate for simulated polyps located on the proximal aspect of
haustral folds.

The purpose of this proposed study is to evaluate the polyp miss rate of
standard colonoscopy and compare/analyze the diagnostic yield obtained from two
differing colonoscopy techniques. In addition, time measurements including;
time to cecum, time for withdrawal and overall procedure time will be analyzed
and reported for each group.

1. Study the overall miss rate of polyps detected with the third eye retroscope
compared to standard colonoscopy.
2. Study the overall miss rate of adenoma detected with the third eye
retroscope compared to standard colonoscopy.
3. Analyze the time observations, including time to cecum, time for withdrawal,
the overall withdrawal time for both groups and the total procedural times for
each colonoscopy procedure

All patients will undergo routine bowel preparation according a standardized
protocol (4L oral laxative).
The endoscopist, the Principal Investigator, a clinical coordinator or a
qualified designee of the Principal Investigator will qualify the subject
candidate using the inclusion/exclusion criteria and will obtain informed
consent of the patient, if he or she is proven suitable.
The subject will be randomized to Group A (study group: a complete routine
colonoscopy followed immediately by a Third Eye colonoscopy) or Group B
(control group; a Third Eye colonoscopy followed immediately by a complete
routine colonoscopy). The subject will be notified of the treatment
designation. The subject then will undergo back to back colonoscopy in
accordance with the randomization process.

The Avantis Third Eye Retroscope auxiliary imaging system includes a catheter,
a cap and a video processor system.
The cap is placed on the tip of colonoscope prior to initiation of the
procedure. The cap contains a polarizing filter that covers the light sources
of the colonoscope, but it does not obstruct the colonoscope*s sensor and
instrument channel.
The catheter is inserted through the instrument channel of the colonoscope
after the tip of the colonoscope has been advanced to the cecum. The flexible
catheter has a J-shaped distal tip with a capsule that contains a camera module
with an image sensor, lens system and related circuitry. The catheter also has
a light source consisting of a light emitting diode (LED). The diameter and the
length of the catheter are designed to fit through a colonoscope*s instrument
channel (minimum diameter of 3.7 mm). Its proximal end has a connector that
snaps into an extension cable leading to the video processor.
The video processor system provides power for the catheter*s sensor and light
source, controls the catheter*s lighting, controls and processes the signal
from the catheter*s sensor and outputs the resulting signal to a monitor for
display. Hardware and software supplied with the system allow single-frame
still images to be recorded for documentation purposes. The Third Eye
Retroscope device is sterilized by the EO process and is intended for single
patient use only.

The order in which the two separate investigations will take place depends on
the group to which the subject is randomized:
Group A: Subject will undergo a complete standard colonoscopy as the first
procedure. Immediately after the first standard colonoscopy procedure a
complete Third Eye colonoscopy will be completed.
Group B: Subject will undergo a complete Third Eye colonoscopy as the first
procedure. Immediately after the first Third Eye colonoscopy procedure a
complete standard colonoscopy will be completed.

The Third Eye Retroscope is similar in size to conventional tools used in the
instrument channel of colonoscopes, including retrieval baskets, ultrasound
probes, cytology brushes, biopsy forceps and polypectomy snares, and the risk
from use of the Third Eye device should be less than or equal to the risk
associated with these commonly-used devices.
Conventional colonoscopes do not allow retrograde viewing of the colon*s folds
and flexures unless the colonoscope is retroflexed, a maneuver that is
generally performed only in the rectum. This limited visualization likely
contributes to documented miss rates for polyps and cancers in the colon.
The Third Eye Retroscope fits through the instrument channel of the
colonoscope, and during withdrawal of the colonoscope it provides a retrograde
view that can reveal abnormalities located in areas that can be hidden from the
forward-viewing colonoscope, such as the proximal aspect of haustral folds and
rectal valves and behind flexures and the ileocecal valve.
There is evidence from previous clinical studies to suggest that the retrograde
view provided by the device actually enabled endoscopists to detect additional
polyps - including many adenomatous polyps - that otherwise would not have been
detected because they were hidden from the view of the conventional
colonoscope.

It can be concluded that the risk/benefit ratio of the Avantis Third Eye
Retroscope is acceptable when used according to the Instructions for Use.