Example of an innovative clinical trial design for a group of medical devices (in this case absorbable hemostats) to support a particular clinically relevant claim

1. Clinical Trials with Medical
Devices:
Example of an Exciting and
Challenging Field
Harrie van Baars, MD
November, 2010

2. The Claim:
Absorbable hemostats are being absorbed by
the body in a certain time frame to prevent
adhesion formation and encapsulation,
ideally with a maximum of 4-6 weeks;

3. The Challenge:
How to support the claim that Absorbable
Hemostats are really being absorbed in a
given time frame when implanted in humans

4. The Problem:
Patients can not be re-operated to proof
efficacy of a surgical procedure, unless
certain complications require re-surgery

5. The Solution:
There are certain diagnostic surgical
procedures that are invasive, needing the
use of hemostats, and may lead to re-surgery
within a given time frame;

6. The Execution:
VAMLA: Video Assisted Mediastinoscopic Lymphadenectomy; In
this procedure lymph nodes are being removed from the
mediastinum with the help of video assistance to perform staging in
lung cancer patients; The staging will then define whether patients
need to undergo lung resection or palliative care; the removal of
lymph nodes may cause bleeding for which hemostats can be
used; In case of resection this usually takes place between 5-25
days after the VAMLA procedure; These patients will be eligible for
the trial

7. Trial Center and Clinical
Investigator:
Martin Hürtgen, MD.
Department of Thoracic Surgery, Katholisches
Klinikum Koblenz, Koblenz, Germany

8. Mediastinoscopy
(VAMLA)
Lymphnode +
Lymph node -
Thorax surgery
Within 5-25 days
Non-
invasivetherapy
Thorax surgery
Within 2-3 mths
None or Palliative
treatment
No rest HemostatRest Hemostat
None or palliative
treatment
The Clinical Trial Design:
Observation à
vue and PA

9. Days 2 4 6 8 10 12 14 16 18 20 22 24 26 28
The Results:ML
10
8
6
4
2
0
Liquid
Solid

10. The Trial Summary:
The application of significant amounts of
oxidised cellulose in the mediastinum
is safe and effective. Gauze measuring 5x20 cm
quickly dissolves and is completely absorbed
within 14 days. The impression of reduced
seroma formation, absence of post-surgical
local inflammation
and adhesion formation is
interesting and suggests a comparative
randomised follow up study

11. The Publication:
“OXIDISED CELLULOSE IN THORACIC SURGERY
– HUMAN IN VIVO STUDY OF EFFICACY, SAFETY
AND ABSORPTION PROPERTIES”
17th European Conference on Thoracic
Surgery, June 2009, Krakow, Poland

12. The Conclusion:
Clinical trials with Medical Devices pose
interesting challenges in comparison with
pharmaceutical compounds. Nevertheless,
with innovative approach and out of the box
thinking excellent results can be obtained.