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Device Technologies and Biomedical Robotics

Device Technologies and Biomedical Robotics - Poster Session E

Poster V16 - Characterization of Motor Enclosures for a Wearable Device to Treat Lymphedema

Saturday, October 26, 2024
10:00 AM – 11:00 AM EST
Location: Exhibit Hall E, F & G

Introduction:  Lymphedema is a chronic disease that affects an estimated 250 million people worldwide and 10 million people in the United States [1]. The chronic, progressive disease is treatable, but not curable, leaving patients with debilitating symptoms that can significantly impair their quality of life [2]. Lymphedema occurs when there is damage to the lymphatic system, most commonly occurring post-surgical removal of lymph nodes due to cancer and radiation treatment. The damage results in a buildup of protein-rich fluid leading to excessive swelling and chronic pain [3]. Existing treatments, such as manual lymphatic drainage (MLD) and mechanical devices, have several limitations, including discomfort and restrictiveness. Lymphedema tends to recur in between appointments leading to the need for more home-based therapies. However, due to the discomfort of many current devices, patient compliance rates at home tend to be lower [4]. To address these challenges, the LymphaVibe team has developed a wearable, vibration-based therapy device that lymphedema patients can use independently. The arm sleeve incorporates embedded eccentric rotating mass (ERM) motors activated in specific patterns designed to mimic MLD techniques. This research study aims to evaluate the effectiveness of encasing ERM motors in various silicone pods versus a 3D-printed hard shell and to quantitatively compare these configurations with clinically used handheld massage devices (HMD) [5].

Materials and

Methods:  Silicone pods were created to house vibration motors using various types of room temperature vulcanizing (RTV) silicone (Smooth-On Dragon Skin). Some pods contained 40 wt% mineral oil (Johnson & Johnson) to mimic soft tissue properties [6]. Three pods were made for each of the following silicone types: Dragon Skin (DS) 10, DS10 with 40 wt% mineral oil, DS20, DS20 with 40 wt% mineral oil, DS30, and DS30 with 40 wt% mineral oil. Additionally, a custom 3D-printed case was fabricated to encase a vibration motor.

Setup A: Each pod was secured to a custom sleeve wrapped around a silicone tissue phantom forearm (DS10 and 40 wt% mineral oil) [5]. An accelerometer (MbientLab, MetaMotionRL) was embedded within the phantom, 12 cm from the bottom (spot 1) and directly across from the pods. Each pod's motor was powered at 2V and 0.2A for ~30 seconds, recording ~6000 data points from the accelerometer. Three trials were conducted for each pod type. The process was repeated with the pods offset 5cm (spot 2) to record acceleration and frequency. This distance was used mimic the positions of the motors in the full wearable used in clinical trials [6].

Setup B: The 3D-printed case was used to hold the motors instead of the pods, and the same methods from Setup A were repeated.

Setup C: A clinically used HMD (Mini Massager) was wrapped with Coban around the tissue phantom, mimicking how Occupational Therapists wrap devices around patients' limbs. Data was recorded at spot 1 and spot 2.

Results, Conclusions, and Discussions: Figure 2 shows the average acceleration of the motor and HMD in spot 1. The highest acceleration was DS10 with oil (1.95g) and DS30 without oil (1.86g). Most of the DS pods exhibited higher acceleration values than the HMD. Figure 3 shows only small frequency variations between DS pod types. Due to the hard material of the 3D printed pod, the frequency was dampened and therefore lower than the DS pods. Figure 4 shows the offset acceleration of the pods by 5cm from spot 1. The results indicate that the DS and 3-D printed pod produced higher acceleration values than the HMD. Figure 5 shows small variations amongst the average frequency values of the DS pods. The HMD value increased slightly due to the offset placement, which directed the vibration directly onto the accelerometer.

The data collected showed DS pods were effective in vibration propagation as they obtained higher baseline values than the HMD. The pods were powered by the same voltage used in the full wearable device which allowed for higher acceleration than that of the fixed HMD. The average frequency data (Figures 3 and 5) had no observable variation amongst DS pod types, but the 3-D printed pod values were lower at spot 2 due to material rigidity. The average acceleration data (Figures 2 and 4) showed that increasing the pod's distance from the accelerometer to spot two resulted in decreased acceleration values, excluding the 3-D printed case. In spot 1, DS10 with oil and DS30 without oil had the highest acceleration. In spot 2, DS20 had the highest acceleration, but the range of accelerations was narrower across all pod designs. Based on this pilot data, further research will be conducted to understand the relationship between distance and acceleration from spots 1 and 2 with varying pod types. This data will help select an effective candidate for the device in future research.

Acknowledgements (Optional):  JDR was supported by the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under award number R25EB033070.



References:
[1] P. Borman, “Lymphedema diagnosis, treatment, and follow-up from the view point of physical medicine and rehabilitation specialists,” Turkish Journal of Physical Medicine and Rehabilitation, vol. 64, no. 3, pp. 179–197, Sep. 2018, doi: 10.5606/tftrd.2018.3539.

[2] E. Poage, M. Singer, J. Armer, M. Poundall, and M. J. Shellabarger, “Demystifying Lymphedema: Development of the Lymphedema Putting Evidence into Practice® card,” Clinical Journal of Oncology Nursing, vol. 12, no. 6, pp. 951–964, Dec. 2008, doi: 10.1188/08.cjon.951-964.

[3] E. D. Paskett, “Symptoms: lymphedema,” Advances in Experimental Medicine and Biology, pp. 101–113, Jan. 2015, doi: 10.1007/978-3-319-16366-6_8.

[4] “Overview of treatment options and review of the current role and use of compression garments, intermittent pumps, and exercise in the management of lymphedema,” PubMed, Dec. 1998, doi: 10.1002/(sici)1097-0142(19981215)83:12b.

[5] Molotkova, E; Thomas, L; Wangler, S; Jarvis, S; Arena, CB; Muelenaer, A; Newberry, T; (2023, September). Safety Evaluation of a Device for Treating Upper Extremity Lymphedema. VRHA Rural Health Voice Conference, Blacksburg, VA, United States.
[6] Y. Wang, B. L. Tai, H. Yu, and A. J. Shih, “Silicone-Based Tissue-Mimicking Phantom for needle insertion simulation,” Journal of Medical Devices, vol. 8, no. 2, Mar. 2014, doi: 10.1115/1.4026508.