Functional Prosthesis Research Articles

Utilizing a fully digital approach for oral squamous cell carcinoma treatment and zygomatic implant-based rehabilitation for maxillary defects.

This clinical report details the functional and aesthetic rehabilitation of a patient with a severe maxillary defect secondary to subtotal maxillectomy for oral squamous cell carcinoma (OSCCM) using a maxillary prosthesis anchored by four zygomatic implants. The procedure involved meticulous subtotal maxillectomy and defect repair with zygomatic implant support, incorporating advanced digital surgical methods, including 3D reconstruction, computer-guided surgery, and photogrammetry (Icam4D). A 3D finite element analysis (FEA) was conducted to assess the method's efficacy in analyzing stress distribution around the zygomatic implants. The patient expressed high satisfaction with the prosthesis's functionality, aesthetics, speech, and swallowing capabilities, underscoring the value of zygomatic implant-supported maxillofacial prosthetics. This synergy of advanced planning, surgical precision, and biomechanical analysis marks a significant advancement in maxillofacial prosthetics.

Design of a Customized Thumb Prosthesis: Focus on Functionality and Comfort

This research focuses on addressing the scarcity of personalized and affordable prostheses in Honduras by designing and developing a functional prosthesis for a thumb. The general objective was to design a model suitable for 3D printing adapted to the specific needs of a patient who had her index and thumb fingers amputated. To achieve this, an integral methodology was employed, ranging from an exhaustive literature review of current solutions to detailed material evaluations, including interviews with patients and medical experts, SolidWorks modeling, and simulations. The result was the successful design of a functional prosthesis prototype, with the selection of intentionally 3D printable materials to ensure comfort and functionality. In conclusion, this research demonstrates the viability of addressing the scarcity of personalized prostheses through innovative approaches and comprehensive design methodologies, with a focus on effectiveness and streamlining the process.

Assocation between trapezium size and failure of total trapeziometacarpal prosthesis. A survival analysis.

To assess the survival function of cementless total trapezium metacarpal prostheses (TTMPs) at 20 years, to compare survival functions by trapezium size, and to evaluate the association between the instantaneous risk of TTMP failure and small trapezium size using a multivariate Cox regression model. This observational cohort study included 221 consecutive patients with a mean follow-up after TTMP of 137.3 months (maximum of 246 months). Kaplan-Meier and actuarial life-table methods were used to evaluate the survival function of thecohort. Kaplan-Meier survival curves were compared by trapezium size. Multivariate Cox regression analysis was used to determine the effect of potential confounders on the association between small trapezium and the instantaneous risk of TTMP failure. At the end of follow-up, there was a 89.01% chance of the TTMP surviving for 246 months or more. There was an association between TTMP survival time and trapezium size showing a significant trend such that the survival curves weresignificantly higher with larger trapezium size (Mantel-Cox test, p = 0.0001; WilcoxonBreslow test, p = 0.0002; Tarone-Ware test, p = 0.0001).The unadjusted Cox regression model showed a significant association between small trapezium size (smaller than 9 mm) and the instantaneous risk of TTPM failure (HR: 7.37, 95% CI: 2.46-22.07). In the multivariate Cox analysis, "age", "trapezium morphology", and "complications" were confounders in the association between small trapezium size and the hazard ratio of prosthetic failure (HR = 3.76; 95% CI 0.96 to 13.82). These results confirm the long-term functional survival of TTMP prostheses and reveal a significant increase in trend of the survival curve with larger trapezium size. Patient age, trapezium morphology, and the presence of post-surgical complications are confounders in the association between small trapezium size and the hazard ratio of TTMP failure.

Adhesion of retinal cells to gold surfaces by biomimetic molecules.

Neural cell-electrode coupling is crucial for effective neural and retinal prostheses. Enhancing this coupling can be achieved through surface modification and geometrical design to increase neuron-electrode proximity. In the current research, we focused on designing and studying various biomolecules as a method to elicit neural cell-electrode adhesion via cell-specific integrin mechanisms. We designed extracellular matrix biomimetic molecules with different head sequences (RGD or YIGSR), structures (linear or cyclic), and spacer lengths (short or long). These molecules, anchored by a thiol (SH) group, were deposited onto gold surfaces at various concentrations. We assessed the modifications using contact angle measurements, fluorescence imaging, and X-ray Photoelectron Spectroscopy (XPS). We then analyzed the adhesion of retinal cells and HEK293 cells to the modified surfaces by measuring cell density, surface area, and focal adhesion spots, and examined changes in adhesion-related gene and integrin expression. Results showed that YIGSR biomolecules significantly enhanced retinal cell adhesion, regardless of spacer length. For HEK293 cells, RGD biomolecules were more effective, especially with cyclic RGD and long spacers. Both cell types showed increased expression of specific adhesion integrins and proteins like vinculin and PTK2; these results were in agreement with the adhesion studies, confirming the cell-specific interactions with modified surfaces. This study highlights the importance of tailored biomolecules for improving neural cell adhesion to electrodes. By customizing biomolecules to foster specific and effective interactions with adhesion integrins, our study provides valuable insights for enhancing the integration and functionality of retinal prostheses and other neural implants.

Replacing Missing Teeth with Screw-Cement Retained Implant Supported Fixed Partial Denture: A Case Report

An accurate impression with proper interocclusal relationship are the two essential criteria used for the best fit and functionality of the final prosthesis when replacing a partly edentulous arch with an implant-supported fixed partial denture. A detailed process about the open tray impression technique and registering the interocclusal relationship for implant- supported partial denture has been described in this case report.

Outcomes of Birmingham Hip Resurfacing Based on Clinical Aspects and Retrieval Analysis of Failed Prosthesis.

This research aims to identify the prevalence of failure for Birmingham Hip Prosthesis (BHR) in total hip arthroplasty and to analyze its reasons from biomaterials and biofunctional perspectives. We present our current analysis and tests on a series of different BHR-retrieved prostheses after premature failure. Relevant clinical data, such as X-ray investigations and intraoperative images for clinical case studies, were analyzed to better understand all factors involved in BHR prosthesis failure. A detailed analysis of the failures highlighted uneven cement distribution, overloading in certain areas, and void formation in the material. A closer investigation using microscopical techniques revealed the presence of a crack originating from the gap between the cement mantle and human bone. Additionally, scanning electron microscopy analyses were conducted as part of the investigation to examine bone cement morphology in detail and better understand the interactions at the interfaces between implant, cement, and bone. In conclusion, this research emphasizes the importance of surgical technique planning and the cementation procedure in the success rate of BHR prostheses. It also underscores the need to carefully evaluate patient characteristics and bone quality to minimize the risk of BHR prosthesis failure. The cementation procedure seems to be essential for the long-term functionality of the BHR prosthesis.

Optimizing Sensor Placement and Machine Learning Techniques for Accurate Hand Gesture Classification

Millions of individuals are living with upper extremity amputations, making them potential beneficiaries of hand and arm prostheses. While myoelectric prostheses have evolved to meet amputees’ needs, challenges remain related to their control. This research leverages surface electromyography sensors and machine learning techniques to classify five fundamental hand gestures. By utilizing features extracted from electromyography data, we employed a nonlinear, multiple-kernel learning-based support vector machine classifier for gesture recognition. Our dataset encompassed eight young nondisabled participants. Additionally, our study conducted a comparative analysis of five distinct sensor placement configurations. These configurations capture electromyography data associated with index finger and thumb movements, as well as index finger and ring finger movements. We also compared four different classifiers to determine the most capable one to classify hand gestures. The dual-sensor setup strategically placed to capture thumb and index finger movements was the most effective—this dual-sensor setup achieved 90% accuracy for classifying all five gestures using the support vector machine classifier. Furthermore, the application of multiple-kernel learning within the support vector machine classifier showcases its efficacy, achieving the highest classification accuracy amongst all classifiers. This study showcased the potential of surface electromyography sensors and machine learning in enhancing the control and functionality of myoelectric prostheses for individuals with upper extremity amputations.

Functional Restoration of Bilateral Wrist Level Hand Amputee with Six-Toe Transfers and Three Free Flaps: An Alternative to Hand Allotransplantation or Prosthesis

Abstract Introduction Hand amputation at the wrist level is severely disabling, especially when bilateral. It is paramount to restore the hand function to the best possible level for the patient's daily living activities, as well as optimal social and occupational rehabilitation. There are various options for restoration of function after amputation at wrist and distal forearm levels including Krukenberg's operation, variations of toe transfers, hand allotransplantation, and prosthesis. Krukenberg's procedure and the reconstruction using toe transfer like Vilkki's procedure or two-toe transfers, restore only the pinch. Hand allotransplantation, although it gives excellent function, has limitations due to the complications of immunosuppression. Functional hand prosthesis, though superior in cosmetic appearance, have again limitations in function, and the cost is prohibitive for most patients in our country. Materials and Methods We present the unique case of a bilateral hand amputation at the wrist level reconstructed with three toes and free anterolateral thigh (ALT) flap in a single-stage surgery for each hand. In two stages, the patient had six toes transferred to both hands. Result All transferred toes and all three free (two ALT and one thoracodorsal artery perforator) flaps survived completely. Three-finger grip (tripod pinch) was thus restored in each hand. The hook grip was also restored well by the reconstructed two fingers. Within 3 months after surgery, the patient could perform all activities of daily living. He resumed his original job with some modification of his work within 6 months postinjury. Conclusion Hand reconstruction using three toes and a free flap is an excellent option for functional restoration for amputation at the wrist and distal forearm level. It allows an early return to function and good social and professional integration of the patient. This procedure is a potential alternative to expensive prosthesis and allotransplantation for a bilateral hand amputation.

One-stage prosthodontically driven jaw reconstruction in patients with benign and malignant pathologies: A 7- to 11-year cohort study.

One stage functional jaw reconstructionis defined as the resection and reconstruction of segmental defects in conjunction with the placement of dental implants in an ideal prosthetic position and loaded with a provisional restoration, during one surgical procedure. The aim of the study is to describe clinical outcomes of patients who underwent one stage functional jaw reconstruction. Patients who underwent one-stage functional jaw reconstruction, from January 2013 to March 2016 were recalled in 2022 and 2023. Planning and execution for the reconstruction utilized either analogue or digital techniques. Outcome parameters recorded were treatment-related outcomes at patient level, implant-related outcomes and patient-reported outcome measures. Eighteen patients underwent one-stage jaw reconstruction with a total of 57 implants. Four patients had maxillary and 14 had mandibular reconstructions. Ten patients underwent postoperative radiotherapy. Ten patients were planned using analogue and eight by digital planning. Three patients had partial flap necrosis, three patients had plate fractures, implant loss was seen in one patient and four patients died during the period. A functional prosthesis was provided in 16 out of the 18 patients. One-stage functional jaw reconstruction is a predictable method for providing rehabilitation with successful outcomes at 7-11 years. However, caution should be exercised when the treatment modality is carried out in patients with malignant pathologies who have undergone radiotherapy.

Evaluation of ozonated olive oil in the success of immediate dental implants placed into infected sockets

Abstract Purpose This prospective study was conducted to assess the clinical and radiographic influences of topical application of ozonated olive oil on immediate implants inserted into infected fresh extraction sockets. Patients and methods This study was implemented on 14 cases with infected nonrestorable teeth or remaining roots. All cases underwent two-stage implant surgery, stage I: extraction of the tooth, application of ozonated olive oil gel into the infected postextraction socket, and immediate insertion of dental implant fixture, and stage II: 4 months after stage I surgery, the abutment was installed onto the implant fixture. After soft tissue healing around the abutment, the implant was loaded with the final functional prosthesis. All the patients had regular follow-up intervals throughout the study period to evaluate soft tissue and bone healing and implant stability. Results Fourteen patients enrolled in this study, of which there were six (42.9%) males and eight (57.1%) females. The age of the patients ranged between 21 and 45 years with a mean of 33.21 ± 9.16 years. The clinical outcomes including visual analog scale, soft tissue dehiscence, infection, implant stability quotient, gingival index, and peri-implant probing depth all indicated uneventful postoperative healing and 100% survival rate of the implants throughout the follow-up intervals. Radiographic outcome included interpreting cone beam computed tomography measurement of alveolar bone height which showed marked significant positive difference between stage I and stage II surgeries indicating a potential enhancing effect of ozonated olive oil on osseointegration and tissue healing. Conclusion Based on the outcomes of this study, we concluded that topical administration of ozonated olive oil might potentially enhance healing and osseointegration of implants immediately inserted into infected fresh extraction sockets and could exhibit a significant influence on increasing the success rate and minimizing complications. However, further investigation employing a control group, larger sample size, and longer follow-up duration is required to confirm this influence.

A Photographic Approach Studying the Orientation of the occlusal plane of the Malaysian Population. A Proposal for an Orienting Device

The occlusal plane is crucial in prosthodontic reconstructive treatment as it affects the most important factors for the proper functioning of the artificial prostheses. The achievement of correct occlusal plane position offers maximum aesthetic, phonetic, mastication, and patient’s satisfaction. An incorrectly oriented occlusal plane interferes with denture stability and retention, in addition to more vital functions of the teeth and oral cavity. This study used a photographic approach to determine the occlusal plane inclination in relation to some anatomical references. 95 young volunteers of Mahsa University College, aged between 20 and 25 years, were selected for this study. The participants were selected according to specific inclusion criteria. A standardized digital profile and front images were taken for each participant using a digital camera that is fixed on a tripod with the fox bite plane placed on the occlusal surfaces of the maxillary teeth. The angle amplitude of the reference planes in relation to the occlusal plane was measured using a digital protractor on the screen display. The results revealed that the least mean angle difference was with the AT1, while higher variability was found using the Frankfort plane. In addition, there were no significant differences between the two genders or among the three ethnic groups. It is concluded that the photographic method can be used successfully to study the occlusal plane, and the lowest point of the tragus is the best posterior reference point to determine the ideal location of the occlusal plane.

The Gritti-Stokes Amputation: Is It Still a Reliable Technique in the 21st Century? A Narrative Review.

Lower limb amputation is a common surgical procedure performed worldwide. Many individuals require amputation due to various circumstances, with amputations occurring above or below the knee. Surgeons rely on published research to determine the most appropriate technique based on intraoperative and postoperative outcomes. The Gritti-Stokes amputation (GSA) procedure, introduced in 1857, has shown positive results in terms of primary wound healing, reduced mortality rates during and after surgery, and accelerated healing and mobility. However, due to the need for highly trained surgeons and limitations in functional and cosmetic prosthesis fitting, concerns have been raised regarding its utility. Additionally, the procedure is underutilized in cases where it could potentially yield better results. This article provides a comprehensive review of the documented benefits of GSA, suitable candidate selection, limitations, various modifications, and a comparison with traditional approaches to lower limb amputation. The review is focused on evidence published in the last 100 years.

Intuitive control of additional prosthetic joints via electro-neuromuscular constructs improves functional and disability outcomes during home use—a case study

Objective. The advent of surgical reconstruction techniques has enabled the recreation of myoelectric controls sites that were previously lost due to amputation. This advancement is particularly beneficial for individuals with higher-level arm amputations, who were previously constrained to using a single degree of freedom (DoF) myoelectric prostheses due to the limited number of available muscles from which control signals could be extracted. In this study, we explore the use of surgically created electro-neuromuscular constructs to intuitively control multiple bionic joints during daily life with a participant who was implanted with a neuromusculoskeletal prosthetic interface. Approach. We sequentially increased the number of controlled joints, starting at a single DoF allowing to open and close the hand, subsequently adding control of the wrist (2 DoF) and elbow (3 DoF). Main results. We found that the surgically created electro-neuromuscular constructs allow for intuitive simultaneous and proportional control of up to three degrees of freedom using direct control. Extended home-use and the additional bionic joints resulted in improved prosthesis functionality and disability outcomes. Significance. Our findings indicate that electro-neuromuscular constructs can aid in restoring lost functionality and thereby support a person who lost their arm in daily-life tasks.

Transcatheter Aortic Valve Implantation for Severe Chronic Aortic Regurgitation.

Transcatheter aortic valve implantation (TAVI) has revolutionised the management of aortic valve disease, offering a less invasive alternative to traditional surgical valve replacement for severe aortic stenosis (AS). TAVI for pure aortic regurgitation (AR) is less well established, and, in fact, it was previously labelled as a relative contraindication. However, TAVI has been utilised for selected cases of pure or predominant AR. The primary limitations regarding the use of TAVI in AR are related to the absence of anatomical factors seen in patients with AS that have contributed to the safe and stable functioning of current-generation prostheses. These include aortic root dilatation, mobile valve leaflets and labile blood pressure within the aortic root, which may further increase the risk of valve migration and periprosthetic leak after deployment. Furthermore, patients with AR have more heterogeneous aortic root anatomies when compared to the population of patients with calcific or degenerative AS. This review article describes the current evidence for the off-label use of TAVI in pure AR and the various clinical syndromes associated with AR where there may be specific challenges in the application of TAVI.

Evaluating the Ability of Brachial Plexus-Injured Patients to Control an Externally Powered (Myoelectric) Hand Prosthesis.

Restoration of hand function after traumatic brachial plexus injury (BPI) remains a formidable challenge. Traditional methods such as nerve or free muscle transfers yield suboptimal results. Advancements in myoelectric prostheses, characterized by novel signal acquisition and improved material technology, show promise in restoring functional grasp. This study evaluated the ability of adults with a BPI injury to control an externally powered prosthetic hand using nonintuitive signals, simulating the restoration of grasp with a myoelectric prosthesis. It also assessed the effectiveness of a comprehensive multidisciplinary evaluation in guiding treatment decisions. A multidisciplinary brachial plexus team assessed adults with compromised hand function due to BPI. The feasibility of amputation coupled with fitting of a myoelectric prosthesis for grasp reconstruction was evaluated. Participants' ability to control a virtual or model prosthetic hand using surface electromyography (EMG) as well as with contralateral shoulder motion-activated linear transducer signals was tested. The patient's input and injury type, along with the information from the prosthetic evaluation, were used to determine the reconstructive plan. The study also reviewed the number of participants opting for amputation and a myoelectric prosthetic hand for grasp restoration, and a follow-up survey was conducted to assess the impact of the initial evaluation on decision-making. Of 58 subjects evaluated, 47 (81%) had pan-plexus BPI and 42 (72%) received their initial assessment within 1 year post-injury. Forty-seven patients (81%) could control the virtual or model prosthetic hand using nonintuitive surface EMG signals, and all 58 could control it with contralateral uniscapular motion via a linear transducer and harness. Thirty patients (52%) chose and pursued amputation, and 20 (34%) actively used a myoelectric prosthesis for grasp. The initial evaluation was informative and beneficial for the majority of the patients, especially in demonstrating the functionality of the myoelectric prosthesis. The study indicates that adults with traumatic BPI can effectively operate a virtual or model myoelectric prosthesis using nonintuitive control signals. The simulation and multidisciplinary evaluation influenced informed treatment choices, with a high percentage of patients continuing to use the myoelectric prostheses post-amputation, highlighting its long-term acceptance and viability. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Efficiency assessment of follow-up methodology of patients with knee replacement to predict post-surgical functionality: a protocol for randomised control PROKnee trial

IntroductionEven when total knee arthroplasty (TKA) is an extended treatment, most patients experience a suboptimal evolution after TKA. The objectives of this study are the following: (1) to determine the...

Non-Obstructive Thrombosis of Mechanical Mitral Prosthesis: About a Case Report and Literature Review

Introduction: Mechanical mitral valve prostheses are vital for patients with mitral valve disease. While obstruction is a well-recognized complication, non-obstructive dysfunction remains less understood. We present a case of non-obstructive mechanical mitral prosthesis to highlight its clinical importance and management challenges. Case Presentation: A 45-year-old female, who had undergone mechanical mitral valve replacement 9 years prior, presented with dysarthria and facial paralysis. Transthoracic echocardiography revealed preserved prosthesis function with no apparent obstruction. However, transesophageal echocardiography confirmed the non-obstructive thrombosis of the mitral prothesis. We opted for a medical treatment consisting in optimizing anticoagulation with the addition of aspirin. The evolution was favorable with complete regression of the thrombus at the control TEO. Discussion: Non-obstructive mechanical mitral prosthesis is a rare entity, often characterized by atypical symptoms. This case emphasizes the importance of comprehensive assessment beyond prosthetic valve gradients. as well as the importance of combining several imaging methods, including radio cinema and TEO. Surgical intervention wasn’t necessary, as the medical treatment was sufficient. Conclusion: Non-obstructive mechanical mitral prosthesis dysfunction can be challenging to diagnose but is crucial to consider in symptomatic patients with mechanical valves. This case underscores the need for a multidimensional approach, including advanced imaging techniques, to uncover and manage non-obstructive prosthesis dysfunction, ultimately improving patient outcomes and quality of life.

Design and Assessment of Bird-Inspired 3D-Printed Models to Evaluate Grasp Mechanics.

Adapting grasp-specialized biomechanical structures into current research with 3D-printed prostheses may improve robotic dexterity in grasping a wider variety of objects. Claw variations across various bird species lend biomechanical advantages for grasping motions related to perching, climbing, and hunting. Designs inspired by bird claws provide improvements beyond a human-inspired structure for specific grasping applications to offer a solution for mitigating a cause of the high rejection rate for upper-limb prostheses. This research focuses on the design and manufacturing of two robotic test devices with different toe arrangements. The first, anisodactyl (three toes at the front, one at the back), is commonly found in birds of prey such as falcons and hawks. The second, zygodactyl (two toes at the front, two at the back), is commonly found in climbing birds such as woodpeckers and parrots. The evaluation methods for these models included a qualitative variable-object grasp assessment. The results highlighted design features that suggest an improved grasp: a small and central palm, curved distal digit components, and a symmetrical digit arrangement. A quantitative grip force test demonstrated that the single digit, the anisodactyl claw, and the zygodactyl claw designs support loads up to 64.3 N, 86.1 N, and 74.1 N, respectively. These loads exceed the minimum mechanical load capabilities for prosthetic devices. The developed designs offer insights into how biomimicry can be harnessed to optimize the grasping functionality of upper-limb prostheses.

SEMG-Based Robust Recognition of Grasping Postures with a Machine Learning Approach for Low-Cost Hand Control.

The design and control of artificial hands remains a challenge in engineering. Popular prostheses are bio-mechanically simple with restricted manipulation capabilities, as advanced devices are pricy or abandoned due to their difficult communication with the hand. For social robots, the interpretation of human intention is key for their integration in daily life. This can be achieved with machine learning (ML) algorithms, which are barely used for grasping posture recognition. This work proposes an ML approach to recognize nine hand postures, representing 90% of the activities of daily living in real time using an sEMG human-robot interface (HRI). Data from 20 subjects wearing a Myo armband (8 sEMG signals) were gathered from the NinaPro DS5 and from experimental tests with the YCB Object Set, and they were used jointly in the development of a simple multi-layer perceptron in MATLAB, with a global percentage success of 73% using only two features. GPU-based implementations were run to select the best architecture, with generalization capabilities, robustness-versus-electrode shift, low memory expense, and real-time performance. This architecture enables the implementation of grasping posture recognition in low-cost devices, aimed at the development of affordable functional prostheses and HRI for social robots.

A scoping review on upper extremity prostheses: Satisfaction, barriers, and their implications in resource-limited countries.

The rates of prosthetic abandonment are not extensively understood especially in resource-limited countries. A scoping review was conducted to examine the literature on the satisfaction with and barriers to using specifically upper limb prostheses. A systematic search of the literature identified 425 studies. After reviewing the articles using predetermined inclusion and exclusion criteria, 7 cross-sectional studies were included in the final review. Barriers to the use of upper limb prostheses include the characteristics of the prosthesis (type, comfort, weight, functionality, price, and availability) and individual patient factors (recent prosthetic user, level of amputation, congenital and accidental limb loss, pain, and duration between amputation and prosthetic fitting). Considering tailored prosthetic design and funding may result in improved prosthetic adherence.