JungHun Choi

Preliminary development of the Active Colonoscopy Training Model

Formal colonoscopy training requires a significant amount of time and effort. In particular, it requires actual patients for a realistic learning experience. The quality of colonoscopy training varies, and includes didactic courses and procedures proctored by skilled surgeons. A colonoscopy training model is occasionally used as part of the training method, but the effects are minute due to both the simple and tedious training procedures. To enhance the educational effect of the colonoscopy training model, the Active Colonoscopy Training Model (ACTM) has been developed. ACTM is an interactive colonoscopy training device which can create the environment of a real colonoscopy procedure as closely as possible. It comprises a configurable rubber colon, a human torso, sensors, a display, and the control part. The ACTM provides audio and visual interaction to the trainee by monitoring important factors, such as forces caused by the distal tip and the shaft of the colonoscope and the pressure to open up the lumen and the localization of the distal tip. On the computer screen, the trainee can easily monitor the status of the colonoscopy, which includes the localization of the distal tip, maximum forces, pressure inside the colon, and surgery time. The forces between the rubber colon and the constraints inside the ACTM are measured and the real time display shows the results to the trainee. The pressure sensors will check the pressure at different parts of the colon. The real-time localized distal tip gives the colonoscopy trainee easier and more confident operation without introducing an additional device in the colonoscope. With the current need for colonoscopists and physicians, the ACTM can play an essential role resolving the problems of the current colonoscopy training model, and significantly improve the training quality of the colonoscopy.

Detection of Looping During Colonoscopy Using Bending Sensors

During colonoscopy, looping of the colonoscope shaft is considered one of the biggest challenges of the proce- dure. It hinders the advancement of the distal tip of the colonoscope requiring time to retract and straighten the shaft. Con- sequently, anesthesia exposure and operative time, and associated risk and cost are all increased. Many active and passive auxiliary devices have been introduced to overcome looping problems but only select devices were utilized due to safety, complexity, or cost issues. In this study, a low cost looping detection system embedded in the shaft of the colonoscope and the corresponding software algorithm have been evaluated. Thirty bending sensors were inserted inside the shaft of the colonoscope, which sent voltage signals to the analog-digital converter. Digital signals were transmitted to the com- puter for software analysis of the looping status of the colonoscope shaft. A colonoscopist can often detect the beginning of the looping process and can initiate maneuvers to correct and avoid the looping, which frequently are successful. A standard colonoscopy training model was utilized to test the looping detection system, which effectively demonstrated loop formation, providing data to the endoscopist that is helpful for initiation of appropriate loop avoidance techniques. Maintenance of the bending sensors and a learning curve of the system can be potential limitations.

Detection of endoscopic looping during colonoscopy procedure by using embedded bending sensors

Background Looping of the colonoscope shaft during procedure is one of the most common obstacles encountered by colonoscopists. It occurs in 91% of cases with the N-sigmoid loop being the most common, occurring in 79% of cases. Purpose Herein, a novel system is developed that will give a complete three-dimensional (3D) vector image of the shaft as it passes through the colon, to aid the colonoscopist in detecting loops before they form. Patients and methods A series of connected links spans the middle 50% of the shaft, where loops are likely to form. Two potentiometers are attached at each joint to measure angular deflection in two directions to allow for 3D positioning. This 3D positioning is converted into a 3D vector image using computer software. MATLAB software has been used to display the image on a computer monitor. For the different configuration of the colon model, the system determined the looping status. Results Different configurations (N loop, reverse gamma loop, and reverse splenic flexure) of the loops were well defined using 3D vector image. Conclusion The novel sensory system can accurately define the various configuration of the colon during the colonoscopy procedure.

Medical Equipment to Make Colonoscopy Procedures Safer for Physicians: Control Head Holder and Splatter Shield

.............................................................................................................................. 3 Acknowledgments............................................................................................................... 5 List of Tables ...................................................................................................................... 9 List of Figures ................................................................................................................... 10 Chapter 1: Introduction ..................................................................................................... 12 1.1 Literature Review.................................................................................................. 13 1.1.1 Colonoscopy Overview ................................................................................. 13 Chapter 2: Endoscopist Risks Involved in Colonoscopy .................................................. 16 2.1 Forces Involved in Colonoscopy .......................................................................... 17 2.2 Risks Involved in Colonoscopy ............................................................................ 19 2.3 Equipment Which Aid Physicians ........................................................................ 21 2.4 Surface Electromyography and Muscle Fatigue ................................................... 24 2.5 Thesis Objectives .................................................................................................. 25 Chapter 3: Development of the Equipment ...................................................................... 27 3.1 Requirements for the Developed Proof of Concept Prototype ............................. 27 3.2 Development of the Proof of Concept Prototype .................................................. 34 3.3 Failure Mode Effect and Analysis ........................................................................ 46 Chapter 4: Methods of Study. ........................................................................................... 55 4.1 Testing of the CHH ............................................................................................... 55 4.1.1 Test of Fatigue Through Surface Electromyography.................................... 55 4.2 Testing of the Splatter Shield. ............................................................................... 58 4.2.1 Drop Test ...................................................................................................... 58 4.2.2 Drop Ball Test ............................................................................................... 60 4.3 Testing of the TH .................................................................................................. 62 4.3.1 Compliance of a Colonoscope Insertion Tube .............................................. 62 4.3.2 Force Test of the TH ..................................................................................... 66 4.4 Equipment Evaluation Through Survey................................................................ 67 Chapter 5: Results and Discussions. ................................................................................. 70 5.1 Validation of the CHH .......................................................................................... 70 5.1.1 Test for Fatigue Reduction Using Surface Electromyography ..................... 71 5.2 Validation of Splatter Shield ................................................................................. 89 5.2.1 Drop Test ...................................................................................................... 89 5.2.2 Drop Ball Test ............................................................................................... 90 5.3 Validation of the TH ............................................................................................. 91 5.3.1 Force Test of the TH ..................................................................................... 92 5.4 Equipment Evaluation Through Survey................................................................ 94 8 Chapter 6: Conclusions ..................................................................................................... 99 6.1 Evaluation of Thesis Objectives ........................................................................... 99 Chapter 7: Future Work .................................................................................................. 103 Bibliography ................................................................................................................... 106 Appendix A – Bill of Materials of the Developed Equipment ....................................... 110 Appendix B Survey Questions for Equipment Evaluation Survey ............................... 116 Appendix C – Equipment Used for the Research ........................................................... 118 9 LIST OF TABLES Page Table 1 Anthropomorphic data of human hip . ................................................................. 30 Table 2 Anthropomorphic data of factor 31 and 20 . ........................................................ 39 Table 3 The anthropomorphic data of factors 24 and 42. ................................................. 40 Table 4 Failure mode effect and analysis of the CHH. ..................................................... 47 Table 5 Failure mode effects and analysis of the Splatter shield. ..................................... 51 Table 6 Failure mode effect and analysis of the TH. ........................................................ 53 Table 7 Classification of groups for the surface electromyography test. ......................... 72 Table 8 MVC values recorded for biceps brachii at pre and post procedure for with support (WS) and without support (WOS) conditions. ..................................................... 73 Table 9 Sphericity tests for the one way repeated measures ANOVA. ............................ 75 Table 10 MVC values recorded for flexor carpi radialis at pre and post procedure for with support (WS) and without support (WOS) conditions. ..................................................... 79 Table 11 Sphericity tests for the one way repeated measures ANOVA. .......................... 81 Table 12 Percentage RMS EMG activity of biceps brachii recorded at the last minute of the trial to the MVC recorded with support (WS) and without support (WOS). .............. 84 Table 13 Sphericity tests for the one way repeated measures ANOVA for muscle activity of biceps brachii ................................................................................................................ 86 Table 14 Percentage RMS EMG activity of flexor carpi radialis recorded at the last minute of the trial to the MVC recorded with support (WS) and without support (WOS) – flexor carpi radialis. .......................................................................................................... 87 Table 15 Drop test results conducted on the prototype shield .......................................... 90 Table 16 Results of the drop ball test on the shield .......................................................... 91 Table 17 Forces recorded at 3 positions for 3 trials on colonoscope of sizes 12.45mm diameter and 13.7 diameter ............................................................................................... 93 Table 18 Factor of Safety for the force grip imparted by the TH for tube diameters 12.5mm and 13.7mm respectively. ................................................................................... 94 Table 19 Bill of materials of the CHH. ........................................................................... 110 Table 20 Bill of materials of the Splatter Shield............................................................. 112 Table 21 Bill of materials of TH. .................................................................................... 115 10 LIST OF FIGURES Page Figure 1 Colonoscopy clinical support [2]........................................................................ 14 Figure 2 Devices that aid colonoscopy – (Right to left, CW) The neck harness, the colonoscope holder and insertion tube holder [29]–[31]. ................................................. 23 Figure 3 Anthropomorphic data (factor 19) of human hip [39]. ....................................... 30 Figure 4 Modelled CHH in Unigraphics NX and the proof of concept prototype. .......... 35 Figure 5 Modelled shield in Unigraphics NX and proof of concept prototype. ............... 35 Figure 6 Working Model 2D simulation of tipping load of the CHH. ............................. 36 Figure 7 Encircled region indicates the region of gripping by the CHH. ......................... 37 Figure 8 Developed ball joint of the CHH. ....................................................................... 38 Figure 9 Factors 31 and 20 from the Human data digest [39]. ......................................... 39 Figure 10 Factors 21 and 42 taken from the Human data digest [39]............................... 39 Figure 11 Rack and pinion arrangement of the CHH. ...................................................... 40 Figure 12 Developed linear actuator for the Splatter shield. ............................................ 41 Figure 13 Developed lock to hold the shield firmly on the bed........................................ 43 Figure 14 Modelled and fabricated Tube Holder. ............................................................. 44 Figure 15 Pictorial depiction of the drop test. ................................................................... 59 Figure 16 Shield which is fastened together for drop test. ............................................... 60 Figure 17 (a) Drop test apparatus (b) The ball impactor. ................................................. 61 Figure 18 Experimental setup to determine

Development of a colonoscopy add-on device for improvement of the intubation process.

A colonoscopy add-on device has been developed to reduce intubation time without modification of the current colonoscope and peripheral devices. One of the main purposes of the system is to minimize trauma caused by the distal tip of the colonoscope. The detachable sensory fixture at the end of the distal tip measures the distance between the distal tip and the colon wall in three directions, and the actuation system attached at the base of the colonoscope controls the distal tip by rotating two dial knobs. The device controls the distal tip to minimize contact between the distal tip and the colon wall, and the distal tip ideally points out the next possible lumen. A compatibility test of the infrared sensory system was carried out, and the design of the actuation system was accomplished. The system is integrated and controlled by a microprocessor. The device was tested in a silicon colon and porcine intestine. The results showed that a colonoscopist successfully reached the cecum with the aid of the colonoscopy add-on device without significant contact between the colon wall and the distal tip. The colonoscopy aid device was very helpful for the novice colonoscopist.

Localization of the Distal Tip in the Colonoscopy Training Model Using Light Sensors

colon. This information also helps the student if he requires inserting a surgical tool along with the colonoscope. In the present study, the distal end of colonoscope is localized using photocells. The colonoscope has a light source for the camera at its distal end. These photocells are connected in basic comparator circuit. The photocells are fitted at specific locations on rubber colon, whose voltage changes on reception of light beam. The photocells are interfaced with a data acquisition system, using which data are acquired. While tracking the distal end, noise created in some photocells at particular instant yields misleading information. In order to avert such occurrence, an algorithm is written separately for advancement and retraction. Using these data, distal end is accurately localized and also specific time required during the test, to pass the colonoscope through specific parts of colon for further analysis.

Development of an Automatic Adjustable Colonoscope

Colonoscopy can be associated with many problems, such as mechanical trauma due to the distal tip contacting the colon wall or health issues due to the extended use of anesthesia. In order to eliminate these complications, an automatic adjustable colonoscope was designed. This device uses sensors, actuators, and a control system to automatically position the distal tip in the center of the colon lumen. The sensors were tested to determine their ability to accurately sense the distance from the tip to the surface. The actuators were tested to determine the correlation between motor rotation and displacement of the distal tip. The control system was tested to assess the ability of the device to position the tip in the center of the test tube and the ability to navigate through a flat test course. It was determined that the sensors could accurately determine distances from 0 to 15 mm from the test surface in all test conditions. The motors for up-down movement and left-right movement of the colonoscope had response times of 0.57 s and 0.69 s, respectively, when the motors were rotated from 0 deg to 90 deg. The control system was able to safely move the colonoscope tip away from all walls of the test apparatus. It was also able to navigate through the flat test course without coming in contact with the walls. The automatic adjustable colonoscope has demonstrated that it can safely and effectively position the distal tip to avoid contact with the walls of the test surface.

The Elastic Limits of Colon Tissues for Different Radii of a Tool Tip End Using a Simple Modeling

Mechanical properties of colon tissues are very important to prevent trauma and perforation during colonoscopy procedure. Most of forces are generated by the shaft of a colonoscope and a distal tip. A shaft of a colonoscope causes mechanical trauma at various locations. A distal tip of a colonoscope can cause not only for mechanical trauma but also serious perforation. In this study, elastic limits of forces were predicted for different sizes of a simplified shape of a tool tip end with a simple characteristic modeling. Published data on the various parts of a colon were used for the reference and a simple way of modeling was applied to estimate the quantity of forces with assumptions. Stress on Descending colon was used and a true stress-strain curve was generated. Descending colon has a wide range of a force limit for two different directions (longitudinal and lateral). A simple characteristic modeling was applied for a spherical shape of tool tip. Even though different parts of a colon and directions will generate diverse results, the model should be insensitive within a limited length and boundary conditions of a colon. The different radii of a tool tip end represent various tool ends from dull to sharp needle-type tool ends in several grades. The results show the elastic limit of force for different radii of tool tip end. The range of tool tip radius is between 0.1 and 10 mm. For the smallest radius of a tool tip, a colon wall will be perforated for a small force (less than 0.05N) and big forces were needed to damage the colon tissue when a tool tip diameter is more than 20 mm with the assumption that the boundary condition of a tool tip test should match up with the simple modeling statement. As the radius of a tool tip end is larger, the contact area between the interface area between a tool tip and a colon wall is wide enough to sustain applied forces. The structure of a human colon was briefly reviewed and determined the elastic limits of forces for different radii of tool ends.Copyright

Design and Simulation of a Smart Endoscope: Part II

In this research, we are developing a noninvasive and safe endoscope for human colonoscopy. To minimize the invasiveness and discomfort, a smart endoscope is composed of a sheath with controllable stiffness that has an exoskeleton structure. A smart endoscope is comprised of an endoscope and a sheath. The stem has more flexibility than a conventional endoscope and the sheath portion maintains controllable flexibility. In principle, this approach could be used for other procedures. The stem of a conventional protoscope has stiffness and it can scratch the inside surface when it pushes into a human colon. It may also deform the colon’s shape. Important parameters used in designing a smart endoscope include the radius of curvature of a sigmoid colon, an appropriate unit diameter for the sheath part, and an ability to lock the units together. An analysis of the cable tensions and external forces is completed for a given configuration based on selected geometric parameters. By applying external forces to the stem of the endoscope, we can solve for the maximum external resisting forces. These are required to maintain the locking ability of the endoscope and the corresponding cable forces.Copyright