Clinical Applications and Future Translation of Somatosensory Neuroprostheses.

Somatosensory neuroprostheses restore, replace, or enhance tactile and proprioceptive feedback for people with sensory impairments due to neurological disorders or injury. Somatosensory neuroprostheses typically couple sensor inputs from a wearable device, prosthesis, robotic device, or virtual reality system with electrical stimulation applied to the somatosensory nervous system via noninvasive or implanted interfaces. While prior research has mainly focused on technology development and proof-of-concept studies, recent acceleration of clinical studies in this area demonstrates the translational potential of somatosensory neuroprosthetic systems. In this review, we provide an overview of neurostimulation approaches currently undergoing human testing and summarize recent clinical findings on the perceptual, functional, and psychological impact of somatosensory neuroprostheses. We also cover current work toward the development of advanced stimulation paradigms to produce more natural and informative sensory feedback. Finally, we provide our perspective on the remaining challenges that need to be addressed prior to translation of somatosensory neuroprostheses.

Implantable antennas for biomedical applications: a systematic review.

This review presents an in-depth examination of implantable antennas for various biomedical purposes. The development of implantable antennas, including their designs, materials, and operating principles, are introduced at the beginning of the discussion. An overview of the many kinds of implantable antennas utilized in implantable medical devices (IMDs) are presented in this study. The article then discusses the important factors to consider when developing implantable antennas for biomedical purposes, including implant placement, frequency range, and power needs. This investigation additionally examines the challenges and limitations encountered with implantable antennas, including the limited space available within the human body, the requirement for biocompatible materials, the impact of surrounding tissue on antenna performance, tissue attenuation, and signal interference. This review also emphasizes the most recent advances in implanted antenna technology, such as wireless power transmission, multiband operation, and miniaturization. Furthermore, it offers illustrations of several biomedical uses for implantable antennas, including pacemaker, capsule endoscopy, intracranial pressure monitoring, retinal prostheses, and bone implants. This paper concludes with a discussion of the future of implantable antennas and their possible use in bioelectronic medicine and novel medical implants. Overall, this survey offers a thorough analysis of implantable antennas in biomedical applications, emphasizing their importance in the development of implantable medical technology.

Long-term complications and implant survival rates after cranioplastic surgery: a single-center study of 392 patients.

Cranioplasty (CP) is a standard procedure in neurosurgical practice for patients after (decompressive) craniectomy. However, CP surgery is not standardized, is carried out in different ways, and is associated with considerable complication rates. Here, we report our experiences with the use of different CP materials and analyze long-term complications and implant survival rates. We retrospectively studied patients who underwent CP surgery at our institution between 2004 and 2014. Binary logistic regression analysis was performed in order to identify risk factors for the development of complications. Kaplan-Meier analysis was used to estimate implant survival rates. A total of 392 patients (182 females, 210 males) with a mean age of 48 years were included. These patients underwent a total of 508 CP surgeries. The overall complication rate of primary CP was 33.2%, due to bone resorption/loosening (14.6%) and graft infection (7.9%) with a mean implant survival of 120 ± 5 months. Binary logistic regression analysis showed that young age (< 30 years) (p = 0.026, OR 3.150), the presence of multidrug-resistant bacteria (p = 0.045, OR 2.273), and cerebrospinal fluid (CSF) shunt (p = 0.001, OR 3.137) were risk factors for postoperative complications. The use of titanium miniplates for CP fixation was associated with reduced complication rates and bone flap osteolysis as well as longer implant survival rates. The present study highlights the risk profile of CP surgery. Young age (< 30 years) and shunt-dependent hydrocephalus are associated with postoperative complications especially due to bone flap autolysis. Furthermore, a rigid CP fixation seems to play a crucial role in reducing complication rates.

Secondary "Hybrid Reconstruction" Concept with Silicone Implants After Autologous Breast Reconstruction - Is It Safe and Reasonable?

BACKGROUND The use of autologous tissue for breast reconstructive surgery following mastectomy has become routine and allows for excellent symmetry and aesthetic results. However, in some cases, the amount of tissue available from the utilized flaps is not enough to achieve the desired outcome. The use of autologous fat grafting, as well as other techniques, has been described to deal with such problems. However, though well-established, these techniques may also fail to achieve the desired results. The aim of this study was to highlight the opportunity to improve aesthetic results using a secondary prosthesis underneath the previously used free flap and to examine whether this is a safe and reasonable procedure. MATERIAL AND METHODS In our study we included patients with unsatisfied aesthetic results after free flap procedures (DIEP, S-GAP, TMG, and FCI) between 2011 and 2018. In each case described, a secondary prosthesis was placed underneath the original flap in order to improve symmetry, shape and projection. Patient age, indication for surgery, adjuvant therapy, complications and outcomes have been registered. A 12-point scale was established to analyze patient satisfaction and aesthetic outcome. RESULTS Overall "operative success" was achieved in all 13 patients (14 flaps) evaluated. At 12 months after reconstruction, all aesthetic scores collected were between good and excellent. In contrast to other studies, we chose a secondary approach for the flap augmentation and we used the epipectoral pocket for the placement of the implant. In our series, low rates of early and late post-operative complications were observed, with a high overall rate of satisfaction. CONCLUSIONS The demonstrated "Hybrid Breast Reconstruction" approach, using an implant underneath a free flap autologous breast reconstruction, provided a safe and reliable option to optimize breast reconstruction outcomes.

Future of Neural Interfaces.

The technological ability to capture electrophysiological activity of populations of cortical neurons through chronic implantable devices has led to significant advancements in the field of brain-computer interfaces. Recent progress in the field has been driven by developments in integrated microelectronics, wireless communications, materials science, and computational neuroscience. Here, we review major device development landmarks in the arena of neural interfaces from FDA-approved clinical systems to prototype head-mounted and fully implantable wireless systems for multi-channel neural recording. Additionally, we provide an outlook toward next-generation, highly miniaturized technologies for minimally invasive, vastly parallel neural interfaces for naturalistic, closed-loop neuroprostheses.

Innovative Spine Implants for Improved Augmentation and Stability in Neoplastic Vertebral Compression Fracture.

Background and objectives: Tumor-related vertebral compression fractures often result in severe back pain as well as progressive neurologic impairment and additional morbidities. The fixation of these fractures is essential to obtain good pain relief and to improve the patients' quality of life. Thus far, several spine implants have been developed and studied. The aims of this review were to describe the implants and the techniques proposed to treat cancer-related vertebral compression fractures and to compile their safety and efficacy results. Materials and Methods: A systematic MEDLINE/PubMed literature search was performed, time period included articles published between January 2000 and March 2019. Original articles were selected based on their clinical relevance. Results: Four studies of interest and other cited references were analyzed. These studies reported significant pain and function improvement as well as kyphotic angle and vertebral height restoration and maintain for every implant and technique investigated. Conclusions: Although good clinical performance is reported on these devices, the small numbers of studies and patients investigated draw the need for further larger evaluation before drawing a definitive treatment decision tree to guide physicians managing patients presenting with neoplastic vertebral compression fracture.

Rapid Globalization of Medical Device Clinical Development Programs in Japan　- The Case of Drug-Eluting Stents.

Delays in the introduction to the Japanese market of drug-eluting stents (DES) developed overseas (i.e., "device lag") decreased sharply between 2004 and 2012. The reduction accompanied a shift in clinical development from a succession pattern (initial product development and approval overseas followed by eventual entrance into the Japanese market) to parallel development (employing multiregional clinical trials (MRCTs)). Although resource-intensive in the short-term, MRCTs are proving to be an effective tool in simultaneous global product development. Creative study designs and the absence of significant ethnic differences in Japanese subjects regarding DES safety and efficacy and the pharmacokinetic behavior of their coating drugs propel this process. More general factors such as medical need and industry incentivization also encourage this shift. Physicians' preference for DES over other percutaneous coronary interventions, the expanding global DES market, and streamlined development and approval prospects each motivate industry to continue investing in DES product development. The efforts of various stakeholders were also integral to overcoming practical obstacles, and contributions by 'Harmonization by Doing' and a premarket collaboration initiative between the USA and Japan were particularly effective. Today, USA/Japan regulatory cooperation is routine, and Japan is now integrated into global medical device development. MRCTs including Japanese subjects, sites, and investigators are now commonplace.

Patients with refractory ascites treated with alfapump® system have better health-related quality of life as compared to those treated with large volume paracentesis: the results of a multicenter randomized controlled study.

BACKGROUND: Refractory ascites (RA) is a complication of cirrhosis which is treated with large volume paracentesis (LVP) as the standard of care. Alfapump® system is a fully implantable pump system which reduces the need for LVP. The aim was to assess health-related quality of life (HRQL) in patients treated with alfapump® versus LVP. METHODS: The data were collected in a multicenter open-label randomized controlled trial (clinicaltrials.gov #NCT01528410). Subjects with cirrhosis Child-Pugh class B or C accompanied by RA were randomized to receive alfapump® or LVP. The SF-36v2 and CLDQ scores were compared between the two treatment arms at screening and monthly during treatment. RESULTS: Of 60 subjects randomized, HRQL data were available for 58 (N = 27 received alfapump® and N = 31 received LVP only). At baseline, no differences were seen between the treatment arms (all p > 0.05): age 61.9 ± 8.4, 79.3% male, MELD scores 11.7 ± 3.3, 85.2% Child-Pugh class B, 70.7% had alcoholic cirrhosis. The mean number of LVP events/subject was lower in alfapump® than LVP (1.1 vs. 8.6, p < 0.001). The HRQL scores showed a moderate improvement from the baseline levels in subjects treated with alfapump® (p < 0.05 for abdominal and activity scores of CLDQ) but not with LVP (all one-sided p > 0.05) in the first 3 months. Multivariate analysis showed that treatment with alfapump® was independently associated with better HRQL at 3 months (total CLDQ score: beta = 0.67 ± 0.33, p = 0.05). CONCLUSION: As compared to LVP, the use of alfapump® system is associated with both a reduction in the number of LVP events and improvement of health-related quality of life.

Anterior Cervical Corpectomy and Fusion and Anterior Cervical Discectomy and Fusion Using Titanium Mesh Cages for Treatment of Degenerative Cervical Pathologies: A Literature Review.

Anterior cervical corpectomy and fusion (ACCF) and anterior cervical discectomy and fusion (ACDF) are 2 effective and safe surgical treatments of degenerative cervical pathologies and are associated with a high percentage of excellent clinical outcomes when a graft or device must be used during the surgery, such as an allograft, autograft, nano-hydroxyapatite/polyamide cages, poly-ether-ether-ketone (PEEK) cages, and titanium mesh cages (TMCs). Although TMCs have been used in cervical surgeries for almost 2 decades, no specific reviews have been performed introducing the state of this material. Thus, in the present review, we discuss the status of using TMCs in anterior cervical surgeries. Studies that tested the usage of TMCs in treating degenerative cervical pathologies were included in this review. The development and progress of TMCs, the biomechanical analysis of TMCs, the radiological and clinical assessment of TMCs, the advantages and disadvantages of using TMCs, and their prospects for future applications as a device of ACCF and ACDF in treating degenerative cervical pathologies are discussed. Studies included in this review showed that TMCs can provide sufficient biomechanical stability. Furthermore, the TMCs used in anterior cervical fusion avoid the donor-site morbidity and achieve a solid bony fusion. However, there are some shortcomings. The structural characteristics and the design of TMCs cause the TMC subsidence rate to remain high, thus resulting in multiple related complications. We believe that due to the virtues of TMCs, they are worthy of application and promotion. However, the structure of TMCs should be further optimized to reduce the TMC subsidence rate and subsidence-related complications, ultimately achieving excellent clinical results.

Nanotechnology in orthopedics: a clinically oriented review.

The utility of nanotechnology in medicine, specifically within the field of orthopedics, is a topic of extensive research. Our review provides a unique comprehensive overview of the current and potential future uses of nanotechnology with respect to orthopedic sub-specialties. Nanotechnology offers an immense assortment of novel applications, most notably the use of nanomaterials as scaffolds to induce a more favorable interaction between orthopedic implants and native bone. Nanotechnology has the capability to revolutionize the diagnostics and treatment of orthopedic surgery, however the long-term health effects of nanomaterials are poorly understood and extensive research is needed regarding clinical safety.

Future of Smart Cardiovascular Implants.

Cardiovascular disease remains the leading cause of death in Western society. Recent technological advances have opened the opportunity of developing new and innovative smart stent devices that have advanced electrical properties that can improve diagnosis and even treatment of previously intractable conditions, such as central line access failure, atherosclerosis and reporting on vascular grafts for renal dialysis. Here we review the latest advances in the field of cardiovascular medical implants, providing a broad overview of the application of their use in the context of cardiovascular disease rather than an in-depth analysis of the current state of the art. We cover their powering, communication and the challenges faced in their fabrication. We focus specifically on those devices required to maintain vascular access such as ones used to treat arterial disease, a major source of heart attacks and strokes. We look forward to advances in these technologies in the future and their implementation to improve the human condition.

The science of neural interface systems.

The ultimate goal of neural interface research is to create links between the nervous system and the outside world either by stimulating or by recording from neural tissue to treat or assist people with sensory, motor, or other disabilities of neural function. Although electrical stimulation systems have already reached widespread clinical application, neural interfaces that record neural signals to decipher movement intentions are only now beginning to develop into clinically viable systems to help paralyzed people. We begin by reviewing state-of-the-art research and early-stage clinical recording systems and focus on systems that record single-unit action potentials. We then address the potential for neural interface research to enhance basic scientific understanding of brain function by offering unique insights in neural coding and representation, plasticity, brain-behavior relations, and the neurobiology of disease. Finally, we discuss technical and scientific challenges faced by these systems before they are widely adopted by severely motor-disabled patients.

Monobloc implants in cementless total hip arthroplasty in patients with Legg-Calve-Perthes disease: a long-term follow-up.

BACKGROUND: The purpose of this study was to evaluate 10-year outcomes in cementless monobloc total hip arthroplasty (THA) in a group of hips with Legg-Calve-Perthes disease (LCPD). METHODS: We reviewed 71 patients (88 hips) who underwent cementless THA with a diagnosis of LCPD from 2003 to 2009. From the total of 71 patients, 34 men and 37 women with an average age of 49.94 years were included. The mean follow-up period was 10 years. RESULTS: The mean Harris Hip Score improved significantly from 46.42 to 89.70. Similarly, the postoperative range of motion, hip dysfunction and osteoarthritis outcome score and SF-12 score also significantly improved. The mean leg lengthening was 22.1 mm. During the follow-up, eight complications were noted, including two cases of intraoperative femoral fractures, two cases of sciatic nerve paralysis, two cases of heterotrophic ossifications, one case of thigh pain and one case of dislocation. One revision was conducted for a periprosthetic fracture, and the survivorship at 10 years was 98.3%. CONCLUSIONS: These data suggest that the monobloc stem can lead to satisfactory outcomes for clinical function, radiological evaluation, restoration of the normal limb lengths, complications, and survivorship among LCPD patients undergoing total hip arthroplasty.

New Trends in Ring Fixators.

Multiple versions of ring fixators are currently available to orthopaedic surgeons. Although the traditional Ilizarov-type ring fixator is still available, many surgeons are now using computer-assisted hexapod frames. There has been a recent surge in the number of different hexapod ring fixators on the market. This article will review some of the new trends in ring fixator hardware and software as well as discuss possible future directions of ring fixator development.

Silver-coated megaprostheses: review of the literature.

Periprosthetic infection remains one of the most serious complications following megaendoprostheses. Despite a large number of preventive measures that have been introduced in recent years, it has not been possible to further reduce the rate of periprosthetic infection. With regard to metallic modification of implants, silver in particular has been regarded as highly promising, since silver particles combine a high degree of antimicrobial activity with a low level of human toxicity. This review provides an overview of the history of the use of silver as an antimicrobial agent, its mechanism of action, and its clinical application in the field of megaendoprosthetics. The benefits of silver-coated prostheses could not be confirmed until now. However, a large number of retrospective studies suggest that the rate of periprosthetic infections could be reduced by using silver-coated megaprostheses.

Advances in the diagnosis and treatment of vestibular disorders: psychophysics and prosthetics.

Although vestibular disorders are common and often disabling, they remain difficult to diagnose and treat. For these reasons, considerable interest has been focused on developing new ways to identify peripheral and central vestibular abnormalities and on new therapeutic options that could benefit the numerous patients who remain symptomatic despite optimal therapy. In this review, I focus on the potential utility of psychophysical vestibular testing and vestibular prosthetics. The former offers a new diagnostic approach that may prove to be superior to the current tests in some circumstances; the latter may be a way to provide the brain with information about head motion that restores some elements of the information normally provided by the vestibular labyrinth.

Frequency Splitting Analysis and Compensation Method for Inductive Wireless Powering of Implantable Biosensors.

Inductive powering for implanted medical devices, such as implantable biosensors, is a safe and effective technique that allows power to be delivered to implants wirelessly, avoiding the use of transcutaneous wires or implanted batteries. Wireless powering is very sensitive to a number of link parameters, including coil distance, alignment, shape, and load conditions. The optimum drive frequency of an inductive link varies depending on the coil spacing and load. This paper presents an optimum frequency tracking (OFT) method, in which an inductive power link is driven at a frequency that is maintained at an optimum value to ensure that the link is working at resonance, and the output voltage is maximised. The method is shown to provide significant improvements in maintained secondary voltage and system efficiency for a range of loads when the link is overcoupled. The OFT method does not require the use of variable capacitors or inductors. When tested at frequencies around a nominal frequency of 5 MHz, the OFT method provides up to a twofold efficiency improvement compared to a fixed frequency drive. The system can be readily interfaced with passive implants or implantable biosensors, and lends itself to interfacing with designs such as distributed implanted sensor networks, where each implant is operating at a different frequency.

Inspiration and application in the evolution of biomaterials.

Biomaterials, traditionally defined as materials used in medical devices, have been used since antiquity, but recently their degree of sophistication has increased significantly. Biomaterials made today are routinely information rich and incorporate biologically active components derived from nature. In the future, biomaterials will assume an even greater role in medicine and will find use in a wide variety of non-medical applications through biologically inspired design and incorporation of dynamic behaviour.