Biomimetic computer-to-brain communication enhancing naturalistic touch sensations via peripheral nerve stimulation.

Artificial communication with the brain through peripheral nerve stimulation shows promising results in individuals with sensorimotor deficits. However, these efforts lack an intuitive and natural sensory experience. In this study, we design and test a biomimetic neurostimulation framework inspired by nature, capable of "writing" physiologically plausible information back into the peripheral nervous system. Starting from an in-silico model of mechanoreceptors, we develop biomimetic stimulation policies. We then experimentally assess them alongside mechanical touch and common linear neuromodulations. Neural responses resulting from biomimetic neuromodulation are consistently transmitted towards dorsal root ganglion and spinal cord of cats, and their spatio-temporal neural dynamics resemble those naturally induced. We implement these paradigms within the bionic device and test it with patients (ClinicalTrials.gov identifier NCT03350061). He we report that biomimetic neurostimulation improves mobility (primary outcome) and reduces mental effort (secondary outcome) compared to traditional approaches. The outcomes of this neuroscience-driven technology, inspired by the human body, may serve as a model for advancing assistive neurotechnologies.

Persistent median artery and communicating branch related to the superficial palmar arch.

Microvascular surgery, plastic and reconstructive hand surgery, and coronary artery bypass surgery call for a microanatomical study of the branching pattern of the superficial palmar arch (SPA). For the anatomical analysis, we used a group of 20 dissected human hands injected with 4% formaldehyde solution and a 10% mixture of melted gelatin and India ink. The morphometric study was performed on 40 human hands of adult persons injected with methyl-methacrylate fluid into the ulnar and radial arteries simultaneously and afterwards corroded in 40% KOH solution for the preparation of corrosion cast specimens. The mean diameter of the SPA, between the second and third common palmar digital arteries, was 1.86 ± 0.08 mm. We identified the persistent median artery (PMA) in 5% of hands. We distinguished the three main groups of the SPAs according to variations in morphology and branching of the arch: Type 1, the long SPA; Type 2, the middle length SPA; and Type 3, the short SPA found in 27.5% of specimens. The communicating branch (CB), a vessel interconnecting the SPA to the closest branch of the radial artery, is classified into two different morphological groups. The third type of incomplete short arterial arch is the most important of the three groups of SPAs. That short SPA is potentially inadequate for restoring circulation after occlusion or radial artery harvesting for coronary artery bypass.

Multifaceted understanding of human nerve implants to design optimized electrodes for bioelectronics.

Bioelectronic medicine is a promising venue for treatment of disabilities using implantable neural interfaces. Peripheral neurostimulation of residual nerves recently enabled multiple functional benefits in amputees. Despite the preliminary promising impact on patients' life, the over-time stability of implants and the related nerve reactions are unclear. To unveil the mechanisms and inform the design of better nerve-electrode interfaces, we engaged a multifaceted approach, merging functional responses from patients, their histological data, and corresponding computational modelling. Neurostimulation evoked different selective sensation locations and qualities over-time, with respective perceptual thresholds, that showed different degree of time stabilities dependent from the stimulating active sites. The histological analysis after explant showed mild tissue reactions, while electromechanically active sites and substrates remained conserved. Computational models, based on patients' histology, revealed the direct influence of the simulated tissue reaction to change of thresholds and type of perceived sensations. Novel insights of electrode biocompatibility was observed compared to animals and the increase of thresholds could be predicted computationally. This multifaced framework suggest that future intraneural implants should have easier implantation and higher biocompatibility counteracting the sensations changes through AI-based stimulations and electrode coatings.

Bone Marrow Aspirate Concentrate versus Platelet Rich Plasma or Hyaluronic Acid for the Treatment of Knee Osteoarthritis.

Background: In the last decade, regenerative therapies have become one of the leading disease modifying options for treatment of knee osteoarthritis (OA). Still, there is a lack of trials with a direct comparison of different biological treatments. Our aim was to directly compare clinical outcomes of knee injections of Bone Marrow Aspirate Concentrate (BMAC), Platelet-rich Plasma (PRP), or Hyaluronic acid (HA) in the OA treatment. Methods: Patients with knee pain and osteoarthritis KL grade II to IV were randomized to receive a BMAC, PRP, and HA injection in the knee. VAS, WOMAC, KOOS, and IKDC scores were used to establish baseline values at 1, 3, 6, 9, and 12 months. All side effects were reported. Results: A total of 175 patients with a knee osteoarthritis KL grade II-IV were randomized; 111 were treated with BMAC injection, 30 with HA injection, and 34 patients with PRP injection. There were no differences between these groups when considering KL grade, BMI, age, or gender. There were no serious side effects. The mean VAS scores after 3, 7, 14, and 21 days showed significant differences between groups with a drop of VAS in all groups but with a difference in the BMAC group in comparison to other groups (p < 0.001). There were high statistically significant differences between baseline scores and those after 12 months (p < 0.001) in WOMAC, KOOS, KOOS pain, and IKDC scores, and in addition, there were differences between these scores in the BMAC group in comparison with other groups, except for the PRP group in WOMAC and the partial IKDC score. There were no differences between the HA and PRP groups, although PRP showed a higher level of clinical improvement. Conclusions: Bone marrow aspirate concentrate, Leukocyte rich Platelet Rich Plasma, and Hyaluronic acid injections are safe therapeutic options for knee OA and provide positive clinical outcomes after 12 months in comparison with findings preceding the intervention. BMAC could be better in terms of clinical improvements in the treatment of knee OA than PRP and HA up to 12 months. PRP provides better outcomes than HA during the observation period, but these results are not statistically significant. More randomized controlled trials and high quality comparative studies are needed for direct correlative conclusions.

Influence of coronavirus disease 2019 pandemic state of emergency in orthopaedic fracture surgical treatment.

PURPOSE: After the appearance of first COVID-19 cases in Serbia, state of emergency was declared on 15 March 2020 and lasted for 54 days. The aim of this report is to compare orthopaedic fracture frequencies in this period, when the walk was limited at the home mostly, with those during the same part in the previous year with regular state, thus to examine staying at home as a factor influencing the frequency of different fracture types. METHODS: There were 86 patients during the state of emergency in year 2020 and 106 patients during the same part of year 2019 with a regular state, having orthopaedic trauma surgery. Number of fractures, gender distribution, and age of patients have been compared between these periods. RESULTS: Total number of fractures decreased for about 19% during the state of emergency. There was nonsignificant difference in fracture frequency for all skeletal areas (p > 0.05), except for distal femoral fractures which occurred more often during the state of emergency (p < 0.05). Female ratio was higher during state of emergency than in regular state for femoral neck fractures. CONCLUSION: Restricted going outside the home for 54 days has the influence in total number of fractures and gender distribution in femoral neck fractures. The method of external fixation used could be assumed as a reducing factor of intraoperative virus pandemic propagation among medical staff.

Do knee injection portals affect clinical results of bone marrow aspirate concentrate injection in the treatment of osteoarthritis? A prospective randomized controlled study.

Aim: To explore the effect that the location of needle placement has on efficacy and tolerability of bone marrow aspirate concentrate injections during treatment of knee osteoarthritis. Methods: Bone marrow aspirate concentrate injections were administered to 111 patients via superolateral, anteromedial or anterolateral portals. Pain was assessed by visual analog scale before and 3, 7, 14 and 21 days after intervention. Knee function was assessed by Western Ontario and McMaster Universities Osteoarthritis Index, Knee Injury and Osteoarthritis Outcome Score and International Knee Documentation Committee scores before and 1, 3, 6, 9 and 12 months after intervention. Results: Significant differences in Western Ontario and McMaster Universities Osteoarthritis Index, Knee Injury and Osteoarthritis Outcome Score and International Knee Documentation Committee scores were observed 12 months post intervention compared with baseline (p < 0.001 for all comparisons). No significant differences in outcome or pain scores were observed among groups. Conclusion: All portals demonstrated similar clinical benefits up to 12 months after intervention. Trial registration number: ClinicalTrials.gov (NCT03825133).

Lower limb replantation: 27 years follow up.

Replantation of lower extremity is a very complex and difficult procedure. There are still a lot of controversies about indications, even numerous scoring systems are now available that can facilitate the surgeon's decision. We present the functional results of a replanted below-knee amputation in an elderly patient, 27 years after the injury and discuss the indication for replantation.

The current state of bionic limbs from the surgeon's viewpoint.

Amputations have a devastating impact on patients' health with consequent psychological distress, economic loss, difficult reintegration into society, and often low embodiment of standard prosthetic replacement.The main characteristic of bionic limbs is that they establish an interface between the biological residuum and an electronic device, providing not only motor control of prosthesis but also sensitive feedback.Bionic limbs can be classified into three main groups, according to the type of the tissue interfaced: nerve-transferred muscle interfacing (targeted muscular reinnervation), direct muscle interfacing and direct nerve interfacing.Targeted muscular reinnervation (TMR) involves the transfer of the remaining nerves of the amputated stump to the available muscles.With direct muscle interfacing, direct intramuscular implants record muscular contractions which are then wirelessly captured through a coil integrated in the socket to actuate prosthesis movement.The third group is the direct interfacing of the residual nerves using implantable electrodes that enable reception of electric signals from the prosthetic sensors. This can improve sensation in the phantom limb.The surgical procedure for electrode implantation consists of targeting the proximal nerve area, competently introducing, placing, and fixing the electrodes and cables, while retaining movement of the arm/leg and nerve, and avoiding excessive neural damage.Advantages of bionic limbs are: the improvement of sensation, improved reintegration/embodiment of the artificial limb, and better controllability. Cite this article: EFORT Open Rev 2020;5:65-72. DOI: 10.1302/2058-5241.5.180038.

Why, when and how propeller perforator flaps in reconstructive surgery.

PURPOSE: The aim of this paper was to evaluate the outcomes of propeller perforator flaps used all over the body, and to appreciate their advantages and/or disadvantages over the free perforator flaps. METHOD: Patients that required propeller perforator flaps used all over the body were eligible to participate in this study. A preoperative Doppler examination was performed for all the flaps in the trunk and thigh, but not regularly in the face, lower leg, foot, forearm and hand. We evaluated the most important technical aspects of harvesting the flaps, the main indications and advantages of using propeller perforator flaps, their disadvantages and complications. For post-excisional face and trunk defects after cancer or decubitus ulcers were performed approximately 25% of flaps. RESULTS: We had very good results in approximately 70% of cases. In the remaining cases, excepting 3 cases in which the flaps were completely lost, we registered only minor complications due to venous congestion, which were solved spontaneously or by skin grafting. CONCLUSION: The main advantages of propeller perforator flaps, i.e. no need of microvascular anastomoses, replacing like-with-like, faster functional rehabilitation, can reduce in well selected cases the indication for free flaps. The rate of complications is not higher than by using other methods. The single real disadvantage of propeller perforator flaps is the location of the perforator close to the defect, what can be an impediment in trauma cases.

Outcomes and special techniques for treatment of penile amputation injury.

INTRODUCTION: Management of severe penile trauma presents great challenges for reconstructive urologists since these injuries vary from abrasions to total emasculation. A review of our case experience with penile amputation is presented, emphasizing techniques used to salvage or reconstruct the most difficult of penile injury cases. MATERIALS AND METHODS: A total of 13 patients with penile amputation injury referred to us between 2007 and 2016 were analyzed. Mean age at surgery was 16 years (ranged from 4 to 29 years). Etiology of penile amputation (partial or total) combined with management and outcomes were evaluated. Management included different surgical procedures with the aim to achieve good functional and esthetical outcomes. Postoperative questionnaire was used for assessment of patient's overall satisfaction. RESULTS: Follow-up ranged from 13 to 182 months (mean 53). Causes of penile injury were iatrogenic trauma (8), self-amputation (2), electrocution (1), intentional sexual assault (1) and mother's hair strangulation (1). Outcome criteria including aesthetic appearance, urinary function and ability to engage in satisfactory coitus, were noted in 11 cases (85%). Two cases with ensuing complications relating to the total phalloplasty required additional treatment due to urethral fistula. CONCLUSIONS: Severe penile injuries should be treated on a case by case basis utilizing the most propitious techniques. We respectfully propose that the needs of such patients are best served by referral centers with extensive experience.

What microsurgeon, orthopaedic and plastic surgeon should know about bionic hand.

Hand loss is a catastrophic event that generates significant demands for orthopedics and prosthetics. In the course of history, prostheses evolved from passive esthetic replacements to sophisticated robotic hands. Yet, their actuation and particularly, their capacity to provide patients with sensations, remain an unsolved problem. Sensations associated with the hand, such as touch, pain, pressure and temperature detection are very important, since they enable humans to gather information from the environment. Recently, through a synergistic multidisciplinary effort, medical doctors and engineers have attempted to address these issues by developing bionic limbs. The aim of the bionic hands is to replace the amputated hands while restoring sensation and reintroducing hand-motor control. Recently, several different approaches have been made to interface this sophisticated prosthesis with residual neuro-muscular structures. Different types of implants, such as intramuscular, epineural and intraneural, each have their own complementary advantages and disadvantages, which are discussed in this paper. After initial trials with percutaneous leads, present research is aimed at making long-term implantable electrodes that give rich, natural feedback and allow for effortless control. Finally, a pivotal part in the development of this technology is the surgical technique which will be described in this paper. The surgeons' insights into this procedure are given. These kinds of prostheses compared with the classic one, hold a promise of dramatic health and quality of life increase, together with the decrease the rejection rate.

"Close-open-close free-flap technique" for the cover of severely injured limbs.

The treatment of severely injured extremities still presents a very difficult task for trauma orthopaedic surgeons. Despite improvements in technology and surgical/microsurgical techniques, sometimes a limb must be amputated, otherwise severe and potentially fatal complications may develop. There is a well-established belief that severe open fractures should be left open. However, Godina proved wound coverage in the first 72 h (after an injury) to be safe and to bring good final results. So early wound cover (no later than one week after an injury) with well vascularized free flaps became the gold standard. Yet for many patients (some of whom have serious health problems), operative treatment needs to be postponed when they arrive to specialized microsurgical departments for microsurgical reconstruction much later than one week after incurring an injury.  As the definite wound cover period from one week to 3 months seems to be hazardous, especially due to the potential of infection, we developed a safe, original flap technique that prevents infection and covers important structures such as exposed bones, tendons, nerves and vessels. We named this technique the "close-open-close free flap technique". It enables difficult wound cover in any biological phase of the wound, by combining complete flap cover first, with the removal of stitches from one side of the flap after 6-12 h. This technique works very well for borderline cases as well; where even after a complete debridement, dead tissue still remains in the wound - making wound cover very dangerous. Closing completely severe open fractures with free (or pedicled) flaps and removing the stitches on one side after 6-12 h, enables orthopaedic surgeons to safely cover any kind of wound in any biological phase of the wound. Additional debridements, lavages and reconstructions can easily be performed under the flap and after the danger of a serious infection has disappeared, definitive wound closure can be carried out.

Emergency toe-to-hand transfer for post-traumatic finger reconstruction: A multicenter case series.

BACKGROUND: The aim of this paper was to evaluate the outcomes of a homogenous series of emergency with a toe-to-hand transfer reconstructions with a different timing: immediate (same surgical step with the debridement), primary (in the first 24 h), early (24-72 h after the debridement) or delayed (72 h-7 days). MATERIALS AND METHODS: Between 2001 and 2011, 31 patients received an immediate reconstruction with a toe-to-hand transfer. Data on indications, timing, type of surgery, complications and outcomes (sensory and motor recovery, patient satisfaction) were extrapolated and recorded. RESULTS: Most of the procedures in our series (71%) were performed in the first 24 h. Survival rate was 100%. The only complications were 3 venous thrombosis (10%), solved with surgical re-exploration. Only 1 patient required secondary surgery for web deepening. No functional problems were recorded at the donor site. Sensibility recovery was acceptable in all patients; toe mobility was higher for the reconstructed thumb (85%) than for other digits (77%). Patient satisfaction was high with regard to functional results and lower but acceptable with regard to the aesthetic outcome. There was no difference in satisfaction rate of patients treated within 24 h or within 7 days. CONCLUSION: No conclusive evidence exists in favor of an immediate versus a primary, early or delayed emergency reconstruction. Emergency toe transfer for finger reconstruction is a safe procedure and its outcomes are comparable to those reported in the literature for secondary reconstruction. Immediate reconstruction has the advantage of an easier dissection, but early or delayed reconstruction gives more time to discuss with the patient and to plan surgery.

Finger defect coverage with digital artery perforator flaps.

AIM: The aim of this paper is to demonstrate the advantages of using local resources in the coverage of such defects. Our approach in fingers' defects is the use of local perforator flaps, both as propeller flaps or bi-lobed pedicled flaps. PATIENTS AND METHODS: After performing an anatomical study on cadaver segments injected with latex followed by transparentation, 81 local perforator flaps in 80 patients during a period of 10 years (2007-2016), i.e. 47 digital artery propeller perforator flaps (DAPP), 10 island transposition perforator flaps (DATP), and 24 bi-lobed pedicled perforator flaps (BLP) were performed in our department. The patients were evaluated regarding finger mobility (ROM), two-points discrimination (TPD), and degree of satisfaction (DS) from cosmetic point of view. RESULTS: The mean interval for social and professional reintegration was 12 days. As complications, we registered only venous congestion in 7 cases followed by epidermolysis in 4 cases and superficial necrosis in 3 cases, which healed by reepithelialization. The range of motion (ROM) of the reconstructed fingers was normal in all the patients. All the flaps regain a satisfactory degree of sensibility (TPD between 4 mm and 14 mm). The DS was relatively high, with 67 patients very satisfied, 11 satisfied, and 2 unsatisfied. CONCLUSIONS: This fast and less invasive method, which replaces like-with-like, allows an early and good reinervation and a rapid social and professional reintegration, proves to be a very reliable alternative in digital defects coverage.

Enhancing functional abilities and cognitive integration of the lower limb prosthesis.

Lower limb amputation (LLA) destroys the sensory communication between the brain and the external world during standing and walking. Current prostheses do not restore sensory feedback to amputees, who, relying on very limited haptic information from the stump-socket interaction, are forced to deal with serious issues: the risk of falls, decreased mobility, prosthesis being perceived as an external object (low embodiment), and increased cognitive burden. Poor mobility is one of the causes of eventual device abandonment. Restoring sensory feedback from the missing leg of above-knee (transfemoral) amputees and integrating the sensory feedback into the sensorimotor loop would markedly improve the life of patients. In this study, we developed a leg neuroprosthesis, which provided real-time tactile and emulated proprioceptive feedback to three transfemoral amputees through nerve stimulation. The feedback was exploited in active tasks, which proved that our approach promoted improved mobility, fall prevention, and agility. We also showed increased embodiment of the lower limb prosthesis (LLP), through phantom leg displacement perception and questionnaires, and ease of the cognitive effort during a dual-task paradigm, through electroencephalographic recordings. Our results demonstrate that induced sensory feedback can be integrated at supraspinal levels to restore functional abilities of the missing leg. This work paves the way for further investigations about how the brain interprets different artificial feedback strategies and for the development of fully implantable sensory-enhanced leg neuroprostheses, which could drastically ameliorate life quality in people with disability.

Sensory feedback restoration in leg amputees improves walking speed, metabolic cost and phantom pain.

Conventional leg prostheses do not convey sensory information about motion or interaction with the ground to above-knee amputees, thereby reducing confidence and walking speed in the users that is associated with high mental and physical fatigue1-4. The lack of physiological feedback from the remaining extremity to the brain also contributes to the generation of phantom limb pain from the missing leg5,6. To determine whether neural sensory feedback restoration addresses these issues, we conducted a study with two transfemoral amputees, implanted with four intraneural stimulation electrodes7 in the remaining tibial nerve (ClinicalTrials.gov identifier NCT03350061). Participants were evaluated while using a neuroprosthetic device consisting of a prosthetic leg equipped with foot and knee sensors. These sensors drive neural stimulation, which elicits sensations of knee motion and the sole of the foot touching the ground. We found that walking speed and self-reported confidence increased while mental and physical fatigue decreased for both participants during neural sensory feedback compared to the no stimulation trials. Furthermore, participants exhibited reduced phantom limb pain with neural sensory feedback. The results from these proof-of-concept cases provide the rationale for larger population studies investigating the clinical utility of neuroprostheses that restore sensory feedback.