Coactivation index of children with congenital upper limb reduction deficiencies before and after using a wrist-driven 3D printed partial hand prosthesis.

BACKGROUND: Co-contraction is the simultaneous activation of agonist and antagonist muscles that produces forces around a joint. It is unknown if the use of a wrist-driven 3D printed transitional prostheses has any influence on the neuromuscular motor control strategies of the affected hand of children with unilateral upper-limb reduction deficiencies. Thus, the purpose of the current investigation was to examine the coactivation index (CI) of children with congenital upper-limb reduction deficiencies before and after 6 months of using a wrist-driven 3D printed partial hand prosthesis. METHODS: Electromyographic activity of wrist flexors and extensors (flexor carpi ulnaris and extensor digitorum) was recorded during maximal voluntary contraction of the affected and non-affected wrists. Co-contraction was calculated using the coactivation index and was expressed as percent activation of antagonist over agonist. Nine children (two girls and seven boys, 6 to 16 years of age) with congenital upper-limb deficiencies participated in this study and were fitted with a wrist-driven 3D printed prosthetic hand. From the nine children, five (two girls and three boys, 7 to 10 years of age) completed a second visit after using the wrist-driven 3D printed partial hand prosthesis for 6 months. RESULTS: Separate two-way repeated measures ANOVAs were performed to analyze the coactivation index and strength data. There was a significant main effect for hand with the affected hand resulting in a higher coactivation index for flexion and extension than the non-affected hand. For wrist flexion there was a significant main effect for time indicating that the affected and non-affected hand had a significantly lower coactivation index after a period of 6 months. CONCLUSION: The use of a wrist-driven 3D printed hand prosthesis lowered the coactivation index by 70% in children with congenital upper limb reduction deficiencies. This reduction in coactivation and possible improvement in motor control strategies can potentially improve prosthetic rehabilitation outcomes.

Assessment of body-powered 3D printed partial finger prostheses: a case study.

BACKGROUND: Traditional prosthetic fabrication relies heavily on plaster casting and 3D models for the accurate production of prosthetics to allow patients to begin rehabilitation and participate in daily activities. Recent technological advancements allow for the use of 2D photographs to fabricate individualized prosthetics based on patient anthropometrics. Additive manufacturing (i.e. 3D printing) enhances the capability of prosthesis manufacturing by significantly increasing production speed and decreasing production cost. Existing literature has extensively described the validity of using computer-aided design and 3D printing for fabrication of upper limb prostheses. The present investigation provides a detailed description of the development of a patient specific body-powered 3D printed partial finger prosthesis and compares its qualitative and functional characteristics to a commercially available finger prosthesis. CASE PRESENTATION: A 72-year old white male with a partial finger amputation at the proximal interphalangeal joint of the left hand performed a simple gross motor task with two partial finger prostheses and completed two self-reported surveys (QUEST & OPUS). Remote fitting of the 3D printed partial finger began after receipt of 2D photographs of the patient's affected and non-affected limbs. Prosthetic fitting when using 3D printable materials permitted the use of thermoforming around the patient's residual limb, allowing for a comfortable but tight-fitting socket. Results of the investigation show improved performance in the Box and Block Test when using both prostheses (22 blocks per minute) as compared to when not using a prosthesis (18 blocks per minute). Both body-powered prostheses demonstrated slightly lower task-efficiency when compared to the non-affected limb (30 blocks per minute) for the gross motor task. Results of the QUEST and OPUS describe specific aspects of both prostheses that are highly relevant to quality of life and functional performance when using partial finger prostheses. CONCLUSION: The use of 3D printing exhibits great potential for the fabrication of functional partial finger prostheses that improve function in amputees. In addition, 3D printing provides an alternative means for patients located in underdeveloped or low-income areas to procure a functional finger prosthesis.

Remote fitting procedures for upper limb 3d printed prostheses.

BACKGROUND: The objective of the current investigation was twofold: i) describe a remote fitting procedure for upper limb 3D printed prostheses and ii) assess patient satisfaction and comfort with 3D printed prostheses fitted remotely. METHODS: A qualitative study using content and score analysis to describe patient satisfaction after remote prosthetic fitting. Research participants reported QUEST and OPUS scores that allow for perceived rating of general aspects and functionality of upper limb prostheses. RESULTS: Six children (three girls & boys, 6-16 years of age) and 2 adult males (25 and 59 years of age) with congenital (n = 7) and acquired (n = 1) upper limb loss participated in this study. Highest device satisfaction items of the QUEST include weight (4.50 ± 0.76), safety (4.38 ± 0.52), and ease of use (4.13 ± 0.64). Functional tasks of the OPUS observe that prosthesis donning and doffing (1.5 ± 0.84) and drinking from a paper cup (1.75 ± 0.89) were the easiest functional tasks. CONCLUSION: The presented methodology for remote fitting of 3D printed upper-limb prostheses exhibits significant potential for rapid fabrication of functional prostheses to developing countries due to increased availability of digital devices in rural areas.