Chee Wee Gan

Precision Control of Piezoelectric Ultrasonic Motor for Myringotomy With Tube Insertion

The current treatment of otitis media with effusion (OME) when medication fails is to surgically insert a grommet tube in the tympanic membrane. A novel precision surgical device has been developed, which allows tube insertion to be accomplished in an office setting. The device leverages on a piezoelectric ultrasonic motor (USM) stage to facilitate the motion sequences for the procedures. The core engine of the device is in the USM motion controller to achieve the high precision, fast response, and repeatability necessary to allow these medical procedures to be efficiently and successfully done with minimum trauma to the patient. This paper focuses on the controller design for the USM to meet the unique set of specifications to apply the surgical device optimally on patient with OME. A model of the USM is first built and identified. A proportional-integral-derivative (PID) controller is used as the main tracking controller with the parameters derived optimally using an linear-quadratic regulator (LQR)-assisted tuning approach. A sign function compensator acts to remove nonlinear dynamics due mainly to friction and a sliding mode controller further rejects remnant uncertainty and disturbance. The experimental results show that the constituent control components fulfill their respective functions well, and collectively, the composite controller is effective toward delivering the level of control performance to meet the objectives for the medical procedures.

Design of a Surgical Device for Office-Based Myringotomy and Grommet Insertion for Patients With Otitis Media With Effusion

Otitis media with effusion (OME) is a very common ear disease occurring in adults and children alike when the middle ear is infected or the eustachian tube becomes dysfunctional, resulting in accumulation of fluid in the middle ear space. When medication as the first treatment fails, a grommet is commonly surgically inserted on the tympanic membrane (TM) of the patient to discharge the fluid. In this paper, a novel “all-in-one” device allowing office-based grommet insertion in an awake patient with OME is proposed, designed, fabricated, and tested. It utilizes a highly integrated structure encompassing key components of a mechanical system, a sensing system and a motion control system, all are synergized to enable the surgery to be completed in a short time automatically, precisely, effectively, and safely. The experimental results obtained with the device working on a mock membrane with characteristics representative of the TM are duly furnished, showing a success rate of up to 98%.

Re-visiting the tympanic membrane vicinity as core body temperature measurement site.

Core body temperature (CBT) is an important and commonly used indicator of human health and endurance performance. A rise in baseline CBT can be attributed to an onset of flu, infection or even thermoregulatory failure when it becomes excessive. Sites which have been used for measurement of CBT include the pulmonary artery, the esophagus, the rectum and the tympanic membrane. Among them, the tympanic membrane is an attractive measurement site for CBT due to its unobtrusive nature and ease of measurement facilitated, especially when continuous CBT measurements are needed for monitoring such as during military, occupational and sporting settings. However, to-date, there are still polarizing views on the suitability of tympanic membrane as a CBT site. This paper will revisit a number of key unresolved issues in the literature and also presents, for the first time, a benchmark of the middle ear temperature against temperature measurements from other sites. Results from experiments carried out on human and primate subjects will be presented to draw a fresh set of insights against the backdrop of hypotheses and controversies.

Mechatronic design of an office-based ventilation tube applicator for patients with Otitis Media with Effusion

Otitis Media with Effusion (OME) is a very common ear disease affecting both children and adults worldwide. Myringotomy and ventilation tube (grommet) insertion on the eardrum is carried out when medication as a treatment for OME fails. In this paper, the current approaches are revisited and the extensive setup and requirements are simplified to a novel “all-in-one” device allowing office-based grommet insertion in an awake patient with chronic OME. The device consists of mechanical system, sensing system and motion control system, which will be elaborated in the paper along with the working process and prototype. Experiments are carried out on ear model with mock membrane and pig eardrum using the Shah type grommet. The results show a success rate of up to 92% on ear models and around 86% on pig eardrums.

Pain mitigation approach in office-based procedure: Case study

This paper discusses pain-related considerations when transforming an operation typically performed under general anesthesia in an operating room, to an office-based procedure by utilizing the automated Ventilation Tube Applicator (VTA). Literature showed that it is advantageous to keep the total procedure time to under 450ms and peak force to under 0.445N for pain mitigation and to minimize middle ear damage. Experiments were carried out to compare manual versus automated procedure and results showed that the automated procedure using VTA has some improvements over the manual one in terms of total time taken and total applied force. However, VTAs peak force is higher than desired. Hence, further optimization of the VTAs parameters is needed to achieve faster time and lower peak force. In-depth experiments were carried out using Taguchis Design of Experiments to distinguish the contributing factors. Using multiple-objective optimization, the optimal parameters for VTA are found.

Intelligent vision guide for automatic ventilation grommet insertion into the tympanic membrane

Otitis media with effusion is a worldwide ear disease. The current treatment is to surgically insert a ventilation grommet into the tympanic membrane. A robotic device allowing automatic grommet insertion has been designed in a previous study; however, the part of the membrane where the malleus bone is attached to the inner surface is to be avoided during the insertion process.

Capacitive-Based Contact Sensing for Office-Based Ventilation Tube Applicator for Otitis Media With Effusion Treatment

Otitis media with effusion is a prevalent condition affecting people of all age groups worldwide. When medication fails, a surgical procedure called myringotomy is done and a ventilation tube (grommet) is inserted. A novel all-in-one device that allows office-based myringotomy was conceptualized and realized, but there exists constraints with respect to contact sensing. This paper will discuss the challenges with contact sensing within the confines of the ear canal in the context of the applicator. A capacitive sensing approach is then proposed to circumvent these difficulties and experimental results are furnished to show the relative performance of capacitive sensing over force sensing for contact detection.

Intelligent vision guide for automatic grommet tube insertion on human Tympanic Membrane

Otitis Media with Effusion (OME), a worldwide common ear disease, occurs in adults and children when the middle ear is infected. The current treatment is to surgically insert a grommet tube onto the Tympanic Membrane (TM) to bypass the Eustachian tube in raining fluid. A robotic device allowing fast and automatic grommet tube insertion has been designed in an earlier work. However, the part of the membrane where the malleus bone is attached to the inner surface is to be avoided so as not to touch or hit the bone during the insertion process. To solve this problem, an endoscope is used to provide the vision guide for the device. Thus, to locate a suitable target spot for tube insertion and plan the working channel trajectory by tracking the malleus from the endoscopic views form crucial steps for a safe and effective OME surgery. This paper mainly focuses on an incorporative optical flow based gradient vector flow active contours algorithm to achieve an online tracking of malleus to guide the working channel to conduct the surgery appropriately and automatically. Preclinical tests are carried out to verify the feasibility and efficacy of the proposed approach.

Novel Mechanical Design of an Ear Surgical Device to Treat Otitis Media with Effusion

Otitis Media with Effusion is an ear disease that requires a surgery to be performed under general anesthesia (GA) to place a grommet in the tympanic membrane for severe cases. An automated grommet insertion device, the Ventilator Tube Applicator (VTA) enables the grommet insertion surgery to be completed in a short time automatically and precisely by automating the incision and insertion process. However, its current design limits the usefulness of the device as it is restricted by the properties of the eardrum, such as the angle, thickness and strength. Therefore, a cover-cutter toolset design with three different setups was conceptualized. Experimental results on mock membrane showed that the new toolset design increased the surgical device’s success rate with a lower force on the tympanic membrane (TM), hence improving the surgical device’s overall efficiency and safety.

Stereo vision based intelligent system for middle ear treatment

Round window, a channel connecting the middle and inner ears, plays an important role in hearing process of human beings. Usually, localized medical treatment to the round window requires surgical treatment to be carried out by professional surgeons. In this paper, we propose a novel approach to explore the potential of robotic-based round window local therapy, leveraging on the technique of stereo computer vision and precise motion control algorithm. In our design, an endoscope acquires stereo images to reconstruct the 3D structure of the middle ear for locating the round window, and a robotic-based working channel will administer the process of drug placement. Once the round window is located via computer vision, the working channel with its end effector (dispensing needle) controlled by a motion controller will be driven to the target point under constrictive conditions of the middle ear. Compared to the traditional manual approaches, the proposed system can render a more accurate and efficient performance, employing precise sensing and manipulation technology outperforming the human senses and control, and thus reducing invasiveness and enhancing the surgery safety. Pre-clinical experiments are carried out to validate the feasibility of the proposed approach.