Hands-on Activity: Designing a Robotic Surgical Device
Educational Standards :
Pre-Req Knowledge (Return to Contents)
Students must understand how to use the electronics, which can be taught as part of the activity by using the five slides in the attached Electronics Introduction Presentation.
It is helpful if students research endometriosis and laparoscopic surgery before starting this activity. Otherwise, see a brief description in the Procedure section.
Learning Objectives (Return to Contents)
After this activity, students should be able to:
Materials List (Return to Contents)
Each group needs:
Materials to make one synthetic abdominal cavity simulator for the class to share:
If using latex tubing in the simulator:
If using bicycle inner tubes in the simulator (a less expensive alternative to latex tubing):
To share with the entire class:
Note: Expendable costs are estimated at $88 for 7-8 groups because you cannot usually buy the items in smaller quantities (so it works out to ~$11 per group). All other "start-up" non-expendable material costs are for reusable items, such as the supplies to build the electronics and abdominal cavity simulator. For materials that will be shared with the entire class (simulator, camera, scale) the total comes to $298. You can save $64 by using used bicycle tubes (free at local bicycle shops) instead of latex sheeting. The electronics come to $146 per group.
Introduction/Motivation (Return to Contents)
(Note: The text of this section is also provided in the attached Design Project Description Handout, as an alternative way for you to make this information easily available to students.)
A local biomedical research and development firm has received a grant to develop a new surgical tool to study, diagnose and treat endometriosis. The firm seeks a competent engineering team to assist with the development of the tool. For this reason, the firm is contracting the initial prototype development to teams from your school. Teams will compete for the full contract of developing a prototype device. The team that best meets or exceeds the objectives will be awarded the contract.
The firm requires a remotely operated device that can inspect the abdominal cavity for endometriosis. (As necessary, explain to students more about endometriosis, as described in the Procedure's Background section and the attached Design Project Description Handout. Or have students research endometriosis independently, prior to starting the activity.) Ultimately, the device will be used by surgeons who suspect endometriosis in a patient.
You will work in teams to design and create a prototype device that can be inserted into the abdominal cavity through an incision in the umbilicus and is remotely operated externally by your team. Once inside the abdominal cavity, the device must inspect all the organs and tissue for disease. If diseased tissue is located, the device shall obtain a biopsy for removal and analysis. The purpose of this device is to reduce the invasiveness of diagnosing endometriosis and provide a platform for researchers to determine how the disease spreads. Although beyond the scope of this project, the final version of the device will be small and robust enough to remain inside the body for at least 60 days. Each day in vivo (in the body), the device will autonomously acquire images and/or video of critical anatomical regions (such as the ovaries and fallopian tubes) in order to better understand how the disease forms and spreads.
Teams will test their surgical devices ex vivo (outside the body) on a benchtop simulator. The simulator represents the abdominopelvic cavity with the small intestine and has a covering that represents the abdominal wall. Each team must make incisions in the abdominal wall in order to place their devices inside the abdominopelvic cavity. Once inside the cavity, the device is out of view, so each device must be equipped with a wireless video camera to transmit the view to the team members.
The research and development firm specifies the following requirements for a successful candidate device:
Vocabulary/Definitions (Return to Contents)
Procedure (Return to Contents)
The inside lining of the uterus is called the endometrium. Endometriosis is a disease in which the endometrium tissue grows outside the uterus in incorrect areas of the body, causing pain, bleeding and infertility. The tissue growth typically occurs in the abdominal cavity in the pelvic area, on the outside of the uterus, the ovaries, bowel, rectum, bladder and peritoneal surface. It is possible, however, for the endometrium to occur in other areas of the body, such as the lungs and even arms and legs, although this is rare. Endometriosis afflicts about 5% of women between the ages of 25 and 40. Little is known about many aspects of the disease. For example, it is unclear how the endometrium forms in the abdominal cavity.
The cause of the disease is also unknown. Further, diagnosis is difficult because endometriosis is hard to detect with ultrasound. Positive identification can occur only with laparoscopic surgery, which is invasive and expensive. During surgery, the surgeon visually inspects the abdominal cavity and acquires images of the afflicted region. Sometimes a biopsy is taken if imaging is inconclusive.
Before the Activity
With the Students
Step 1: Introduce the design project; discuss the problem and motivation behind the project.
Step 2: Review or teach students the steps of the engineering design process, as well as tips and guidelines for successful brainstorming (see suggested resources in the Additional Multimedia Support section). Begin with "low constraint" brainstorming, in which students' ideas are not limited to the building materials provided for the activity. Instead, they imagine real solutions that could be accomplished by an engineering team. Students take turns presenting their "low constraint" brainstorming ideas (2 or 3 minutes each). An example of low constraints for creating and testing the first prototype:
Step 3: Introduce the building materials and provide a list of materials. Introduce the electronics and present the attached Electronics Introduction Presentation. Have students test the electronics by connecting the battery pack, receiver, switch and servos as outlined in the presentation.
Step 4: Begin "high constraint" brainstorming session based on the time, materials and resources made available for this activity. Direct teams to work towards generating three distinct solutions to the problem. Continue brainstorming into a second class period, as necessary, creating sketches of the three ideas and turning in drawings at the end of class. The teacher reviews the drawings to provide feedback and comments, and approves if ready to go.
Step 5: If a group's designs are approved, then its team members discuss which of the three designs to choose for the prototype design. Have students write paragraphs justifying their choices. If designs are not approved or could not be understood, then teams redraw/redesign/explain their designs in order to get approval. Hand out the Competition Scoring Rubric and explain it to students before construction begins.
Step 6 (Building Phase Begins): Start building! Throughout the building phase of the design project, assess students on their progress to meet a series of five milestones. These interim deadlines keep students progressing at an acceptable rate to finish their projects. Without milestones, students tend to fall behind and save most of the work for the very end. After every milestone, have students describe improvements they will make to increase their devices' performance.
Milestone 1: Critical design review: Students explain how their final designs fulfill the project requirements. (Timing: assess shortly after building begins: ~3.5 hours into building phase)
At this point, students should be able to answer questions such as: How does your device move forward and backward? How does it turn? Which servos are you using? What are the functions of each servo? How do you take a biopsy? Where have you placed the camera?
Milestone 2: Partial mobility: Devices can move forward and backward in the abdomen. (Timing: assess ~7.5 building hours after Milestone 1)
Teams should be able to drive their devices from one end of the abdomen, over the hill to the other side of the abdomen. Give them the choice of either picking up their devices, turning them around to face forward, and then driving over the hill again to reach the starting point, or removing the hill and driving backwards to reach the starting point.
Step 7: To break up the long building phase, conduct the following engineering drawing lesson and activity between Milestones 2 and 3. See Detail Drawings: Communicating with Engineers (lesson) and Drawing Designs in Detail (activity).
Step 8: Continue the building phase.
Milestone 3: Full mobility: Devices can move forward, backward and turn in the abdomen. (Timing: assess ~6.5 building hours after Milestone 2)
Devices must be able to start at one end of the abdomen, drive over the hill to the other side of the abdomen, turn around, and drive back over the hill to return to the starting point.
Milestone 4: Blind mobility: Students can drive their devices in the abdomen with use of the camera. (Timing: assess ~9 building hours after Milestone 3)
Before test day, place four differently colored PlayDoh clumps in different sites of the abdomen. Place a plastic contractor trash bag over the abdominal cavity simulator so that students cannot see inside (open end of the bag facing the entrance so no incisions need be made at this point). For the test, give teams five minutes to place their devices into the abdomen, drive up to all four sites of endometriosis, and exit the abdomen, relying solely on the camera to complete the task.
Milestone 5: Biopsy demonstration: Devices can remove two grams of diseased tissue from the abdomen. (Timing: assess ~9 building hours after Milestone 4)
Before test day, place four differently colored PlayDoh clumps in different sites of the abdomen. Place a plastic contractor trash bag over the simulator so that students cannot see inside (open end of the bag facing the entrance so no incisions need be made at this point). For the test, give teams five minutes to place their devices into the abdomen, drive up to one site of endometriosis of their choice, take a biopsy of at least 2 grams, and exit the abdomen, relying solely on the camera to complete the task.
Step 9: Have students draw or describe the steps of the engineering design process and describe their experiences thus far with each step of the design process.
Step 10: Review the rubric and project objectives.
Step 11: Have teams refine their device prototypes and make improvements. Dedicate about three classroom hours to refinement of the devices.
Step 12: Projects are due. Conduct a class competition. Grade team prototypes using the rubric. As time permits, assign team presentations and marketing tasks, as described in the Assessment section.
Attachments (Return to Contents)
Safety Issues (Return to Contents)
Troubleshooting Tips (Return to Contents)
Due to the number of electronic components involved in this activity, it is advised that the instructor familiarize him/herself with their operation and function.
Students often encounter dead batteries, usually because electronics are left powered on after class. Frequently remind students to turn off the transmitters and receivers when not in use.
Investigating Questions (Return to Contents)
Assessment (Return to Contents)
Design Process Quiz: Ascertain students' understanding of the design process by administering the Engineering Design Quiz to the class before beginning any discussion about engineering design. For an overall pre/post assessment of students' understanding of engineering design, administer the same quiz at the conclusion of the activity.
Research: Direct students to research endometriosis and laparoscopic surgery on the Internet or at the library. Require students to write a paragraph, poem, or song about either endometriosis or laparoscopic surgery to demonstrate their understanding. In groups of four, have students share their paragraph, poem, or song with each other. Then have each group choose one paragraph, poem, or song to share with the entire class.
Activity Embedded Assessment
Milestones: To assess student progress throughout the design project, use the five milestones described in the Procedure section.
Design Process: At a point after the five milestones, assess students' understanding of the design process and how it relates to their projects by having them draw or describe the steps of the engineering design process and describe their experiences thus far with each step.
Competition: The final assessment is the class competition. Use the requirements and scoring criteria provided on the attached Competition Scoring Rubric.
Presentation: Assign students to give presentations that detail their design process and competition test results. Require that they provide backgrounds on endometriosis and motivations for the design projects, as well as possible improvements to their designs.
Marketing: Assign student teams to make commercials or advertising posters that could be used to sell the devices by the local biomedical firm that contracted them to design the surgical tool.
Activity Scaling (Return to Contents)
To reduce the amount of time for this project (by approximately 9 classroom hours), eliminate the requirement that students obtain biopsies of the endometriosis (PlayDoh), which also eliminates Milestone 5. The amount of time for this project can further be reduced (by approximately 8 more hours) if the hill inside the abdomen is removed. If both the biopsy and hill requirements are eliminated, then the amount of time required to complete this project would be reduced by 17 hours to approximately 30 total classroom hours.
To make this activity more suitable for younger students (grades 9-10), use some or all of the following suggestions to simplify the robot design and/or its control:
Additional Multimedia Support (Return to Contents)
See a description of the steps of the engineering design process at http://www.teachengineering.org/engrdesignprocess.php
Introduce students to the engineering design process by conducting the Creative Engineering Design unit at http://teachengineering.org/view_curricularunit.php?url=http://www.teachengineering.org/collection/cub_/curricular_units/cub_creative/cub_creative_curricularunit.xml
Introduce students to brainstorming by conducting the Brainstorm Possible Solutions activity at http://teachengineering.org/view_activity.php?url=http://www.teachengineering.org/collection/cub_/activities/cub_creative/cub_creative_activity3.xml
References (Return to Contents)
GI Crawler. Advanced Medical Technologies Laboratory. University of Colorado Boulder. Accessed November 9, 2011. (Description of a research project to develop a mobile capsule-sized crawler for exploration of the gastrointestinal [GI] tract. Involves research into GI tissue mechanics characterization and modeling; micro-tread design and experimentation; and tread-tissue interaction and contact mechanics.) http://www.colorado.edu/engineering/articles/surgical-crawlers
Other Related Information (Return to Contents)
Towards the end of the project, show students pictures of the actual research upon which this activity is based to give the project more meaning and solidify that they are working on a design project with the potential to make a difference in people's lives. The activity project is based on research in the Advanced Medical Technologies Laboratory in the College of Engineering and Applied Science at the University of Colorado Boulder. See details of this ongoing research project (GI crawler) and others (VSD camera, pain quantification, port camera, boutonniere brace) at: http://www.colorado.edu/mechanical/amtl/Projects.htm
ContributorsBenjamin S. Terry, Brandi N. Briggs, Stephanie Rivale, Denise W. Carlson
Copyright© 2011 by Regents of the University of Colorado.
Supporting Program (Return to Contents)Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Acknowledgements (Return to Contents)
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.