GERD Valve Gastroesophageal reflux disease

1
GERD Valve(Gastro-esophageal reflux disease)

• David Ugai, Dan Carlson, Joe Bothwell, Carter
  Vogds, Ben Roedl, and Joel Miesfeld
• Client Professor John Webster
• Advisor Professor Damian Bird

2
(No Transcript)
3
Overview

• GERD (with problem statement)
• Current methods of treatment
• Client requirements
• Dan and Joels design
• Joe and Carters design
• David and Bens design
• Future work

4
Problem Statement

• In order to prevent GERD, gastro-esophageal
  reflux disease, our goal is to design an
  implantable valve. The valve must be a passive
  two-way valve that opens at low pressures in the
  downward direction for food to pass and at high
  pressures in the upward direction for burping and
  vomiting. The goal is to permanently prevent
  gastric contents refluxing from the stomach into
  the esophagus, which causes irritation and pain
  to people with GERD.

5
Background Information

• The upper digestive anatomy
• .1 M HCl
• pH1
• The esophagus moves food by peristalsis.

Figure 1. Diagram of upper digestive
system. http//www.gerd.com/intro/frame/grossovw.h
tm
6
Background cont. (The LES)

• The Lower Esophageal Sphincter
• Normally prevents acid from refluxing
• Relaxes to let food pass through.
• Maintains a pressure of 15-30 mmHg

Figure 2. The lower esophageal sphincter http//ww
w.becomehealthynow.com/article/bodydigestive/727/
7
GERD

• Symptoms
• Heart burn
• Regurgitation
• nausea
• Reflux
• LES too weak
• Stays relaxed

Figure 3 Image of LES with GERD (Jackson
Gastroenterology, 2004)
8
Treatments

• Eating habits
• Sleep
• Medications
• Surgery

9
Fundoplication

• Stomach wrapped around esophagus
• One way valve
• Allows food in
• Prevents GERD

10
Side Effects of Fundoplication

• Bloating
• Most symptoms improve
• 3 severe
• Inability to belch

11
Client Requirements

• Must be a two-way valve
• Must open to allow food to enter the stomach
• Must open to allow gas and vomiting to exit the
  stomach
• Withstand a pH level of 1

12
Hourglass pressure valve

• Dan Carlson
• and
• Joel Miesfeld

13
Goals of Design

• Accepted by body
• Withstand degradation under constant contact with
  concentrated HCl
• As non-invasive and simple as possible
• Flexible material that can move with peristalsis
  of esophagus
• Easy downward opening
• Pressure needed to open upwards

14
Proposed Design

• Flush with esophagus walls to allow for
  peristaltic contractions to pass food downward
• Increased thickness toward middle to require high
  pressure to open in upward orientation
• Relies on pressure

GERD Valve
L.E.S.
Proximal Stomach
15
Valve Orientations

• Intake is by easy passage
• Gas or Vomit must exert a large force to move
  upward

16
Testing Required

• Test to determine if sutures are needed to
  eliminate vertical movement
• Study pressures involved in vomiting and burping
  and gauge stiffness of material along these lines

17
Hydrogels

• Hydrogels are pH sensitive material
• The material expands with lower pH and shrinks
  with high pH
• Material could be used to coat valve
• Have been tested in-vivo in human subjects in the
  Netherlands (few ill effects were observed)

18
Spring-Loaded Pressure Device

• Joe Bothwell
• and
• Carter Vogds

19
Proposed Design

• Would be inserted inside the LES via the
  esophagus
• Spring composed of stainless steel and set inside
  a plastic polymer
• Strength of K constant to be determined.

Figure 1. Drawing of proposed Spring design
20
LES Diagram
Figure 2. Cross sectional diagram of the
LES http//www.solvaypharma.ca/en/areas/images/ori
ginal_gastro_images/10B-LESnotwork_L.jpg
21
Materials

• Stainless steel
• Corrosion resistant
• Long lifespan
• Polymer coated
• Many polymers are safe to use for human implants.
• Ex. Heart valves, knee replacement,

22
Design Pros

• Does not come in contact with stomach acid
• Minimally Invasive
• Device longevity can supersede that of
• patients life
• Simple Design
• Reduces possibility of malfunction
• Inexpensive
• The device has a high likelihood of success

23
Further Considerations

• Must be custom fit for each recipient due to the
  fact that desired constricting pressure will vary
  from person to person.
• Implant procedure may be difficult
• Some recipients may continue to experience GERD
  symptoms after the procedure
• Not all patients will be candidates for the
  implant.

24
Further Considerations

• The sphincter may not continue to function
  correctly if it does not support the implant.
• If the device malfunctions and needs to be
  removed, sphincter function may be further
  compromised.
• Implant may cause discomfort to the recipient,
  particularly while swallowing.
• A large amount of data collection would be
  necessary in order to initiate human trials.

25
Projected Deliverables

• The simple design of the device should allow for
  the construction of a prototype.
• Animal testing could be a possibility given the
  realization of a working prototype.
• The mechanical dynamics are simple, allowing for
  accurate models to be formed before construction.

26
References

• http//www.gerd.com/intro/frame/grossovw.htm
• http//www.becomehealthynow.com/article/bodydigest
  ive/727/
• Dr. Kao, University of Wisconsin
• Associate Professor of Biomedical Engineering

27
Rotating Disc Device
David Ugai and Ben Roedl
28
Proposed Design

• Disc (weighted)
• Stoppers
• Grooves
• Shape

29
Design (continued)

• Bottom stopper
• Holes (allows pressure)
• Groove
• Incline of Groove

30
Intake vs. Release
31
Further Considerations

• Pressure values for intake and release must be
  known
• Need to find a flexible biomaterial
• Need to find a biomaterial able to withstand
  strong acid
• Extensive testing needed

32
Future Work

• Meet with client
• Discuss designs as a team
• Decide pros and cons of each design
• Choose a design
• Begin to investigate biomaterials for project