Finger Flexion Research Articles

Social negotiation and “accents” in Western lowland gorillas’ gestural communication

Recent findings on chimpanzee infants’ gestural development show that they use some gesture types flexibly and adjust them depending on their interaction partner and social context, suggesting that gestural communication is partly learnt and partly genetically determined. However, how gesture types are shaped by social and demographic factors remains unclear. We addressed this question by focusing on gesture type morphology and conducted a fined-grained analysis of gestural form during intraspecific social-play interactions in two captive groups of Western lowland gorillas (Gorilla gorilla gorilla). We focused on the most frequent gesture types (beat chest, slap body, slap ground and touch body) produced by subadults (infants, juveniles and adolescents). We considered twelve morphological gesture characteristics (e.g., horizontal and vertical hand trajectories, fingers flexion and spread). Our multifactorial investigation shows that morphological characteristics of distinct gesture types can be shaped by social factors, namely signaller’s sociodemographic characteristics (group and kinship), signaller’s behavioural characteristics (body posture) and context-related characteristics (recipient’s sex, attentional state and position in the signaller’s visual field). We nurtured the lively debate concerning gesture origins by revealing the existence of “accents” in non-verbal communication and the highly variable adjustment of gestural form to different conspecifics and interactional characteristics, which supports the revised social negotiation hypothesis.

THE EFFECT OF A MODIFIED TENODESIS WRIST-HAND ORTHOSIS ON HAND FUNCTION IN PATIENTS WITH TETRAPLEGIA

BACKGROUND: An individual experiencing tetraplegia faces functional limitations due to impaired hand function. The use of an affordable tenodesis wrist-hand orthosis (WHO) can enable finger flexion with active wrist extension, thereby enhancing the three-jaw chuck grasp and overall hand functionality. OBJECTIVES: To assess hand function and satisfaction in patients with tetraplegia using a modified tenodesis wrist-hand orthosis (WHO), utilizing the Duruöz Hand Index (DHI) and the Orthotics and Prosthetics User Survey (OPUS) satisfaction with device and services subscales. METHODOLOGY: The study was conducted at a tertiary care center in central India, enrolling patients with tetraplegia admitted to the Department of Physical Medicine and Rehabilitation. A modified tenodesis wrist-hand orthosis (WHO) was designed using low-temperature thermoplastic components. Twenty-two individuals with a minimum wrist extensor power of grade 3/5 were included in the study. These patients were provided with the modified tenodesis WHO and underwent daily training sessions for a period of 2 weeks. Duruöz Hand Index (DHI) scores were assessed at baseline, 6 weeks, and 12 weeks post-enrolment. Patient satisfaction was evaluated using the Orthotics and Prosthetics User’s Survey (OPUS) satisfaction with device and services subscales. FINDINGS: The analysis of the DHI scores indicated a significant enhancement in functional abilities at both 6-week and 12-week follow-ups compared to the baseline assessment. Notably, the most substantial progress at 6 weeks follow-up was observed in tasks such as buttoning a shirt, while significant improvement at the 12-week mark was noted in activities like turning a key in a lock. The median OPUS device satisfaction score was 50, corresponding to a Rasch score of 68.8. Additionally, the median OPUS satisfaction score for services stood at 46, with a Rasch score of 72.7. Patients expressed the highest satisfaction levels with the courteous demeanor of the staff, prompt scheduling of appointments, and accurate fitting of the orthosis. CONCLUSION: The study findings indicate that the modified tenodesis WHO is an effective and satisfactory therapeutic device for improving hand function in patients with tetraplegia. The findings encourage further investigation and application of the modified tenodesis WHO in clinical practice. Layman's Abstract Individuals who are affected due to spinal cord injury (SCI) are often unable to perform the basic daily activities of life due to weakness. The hands are one of the most specialized parts of the human body and loss of its function can be incapacitating. Certain wrist hand orthoses (WHO) can aid such individuals by assisting the weak hand muscles. One such WHO is a tenodesis wrist hand orthosis. Modifications to the previously available tenodesis wrist hand orthosis were made to make it cheaper, lighter, and easier to manufacture. The effectiveness of this modified tenodesis WHO on improving hand activity and satisfaction in the individuals using it was assessed in this study which was conducted in a tertiary care center in central India. Twenty-two individuals with cervical SCI, who had some ability to extend their wrists against gravity, were admitted to the Physical Medicine and Rehabilitation department and enrolled in this study. Notable improvements were observed in functional tasks such as buttoning a shirt, opening a lock, eating with a fork, brushing teeth, and writing, with considerable satisfaction in those trained with the modified tenodesis WHO. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/42879/33253 How To Cite: Sonune S.P, Saha A, Joshi N.G, Pathak S, Bhadra P, Goel G. The effect of a modified tenodesis wrist-hand orthosis on hand function in patients with tetraplegia. Canadian Prosthetics & Orthotics Journal. 2024; Volume 7, Issue 1, No.8. https://doi.org/10.33137/cpoj.v7i1.42879 Corresponding Author: Dr. Anyesha Saha,Affiliation: Department of Physical Medicine and Rehabilitation, All India Institute of Medical Sciences, Saket Nagar, Bhopal (M.P.), India.E-Mails: saha.anyesha@gmail.com; anyesha.sr2023@aiimsbhopal.edu.inORCID ID: https://orcid.org/0009-0004-1574-0519

Leveraging wearable sensors and machine learning for posture-based detection of carpal tunnel syndrome

Abstract Carpal tunnel is associated with long-term use of the wrist and hand for various activities such as typing, welding, or poor working postures. Carpal Tunnel Syndrome (CTS) may cause severe pain and discomfort in the hand and wrist, and in some circumstances, surgery becomes inevitable. The objective of this study is to prevent typing postures, which can be ascertained as predisposing subjects to CTS development. The data used in this study is an array of wrist wearable sensors to capture flexion, extension, and bending of fingers while using a keyboard or mouse. Machine learning is employed on the data in order to identify risk factors indicative of a high probability of CTS. The analyzed models are linear regression, Support Vector Machine, Random Forest, Multilayer Perceptron, Convolution Neural Network, and Long Short Term Memory. The conditions for assessing the performance of the data models include RMS error, coefficients of determination, and mean absolute percentage error. In this research, I conducted an exploratory data analysis (EDA) to gain an initial understanding of the dataset. Following the exploratory phase, I applied feature extraction techniques, specifically Principal Component Analysis (PCA). As put forward for the proposed research, the strategies to prevent risky occupations have broad potential at the present time, especially in the case of CTS when preventing repetitive wrist movements.

The Effect of Forearm Shortening on Finger Flexion: A Biomechanical Study

Surgeons may shorten the forearm for many indications. We quantified the impact of shortening on finger flexion with a cadaver model. Ten fresh cadaver proximal forearms were pinned to a static block. We pinned each distal forearm/hand to a block that could unlock, slide, and relock on a mounting track. This block allowed wrist-neutral or 30-degree extension. With the sliding block locked, we removed the central 10 cm of the radius/ulna. We placed sutures in the proximal end of each flexor digitorum profundus (FDP). After pretensioning, we simulated near-maximum baseline FDP muscle-generating force by applying 100 N via a load cell at the proximal sutures. We then anchored the load cell system proximally to set the initial length-tension relationship for simulating near-maximum baseline muscle-generating force. We called subsequent load cell readings the simulated muscle force (SMF) and pressure sensor readings between fingertips and the palm the tip-to-palm force (TPF). We shortened the forearm in 1 cm increments with the distal sliding-locking block. At each increment, we recorded SMF and TPF in the wrist-neutral position. Once a specimen lost measurable TPF, we applied 30 degrees wrist extension until again losing TPF. Incremental forearm shortening was associated with exponential decreases in each FDP's SMF and TPF. In wrist-neutral, 3 cm mean shortening had a loss of 99% and 98% SMF and TPF, respectively. Wrist extension marginally improved SMF and TPF up to 4 cm mean shortening, where both lost 99%. Loss of any fingertip touchdown occurred after a mean shortening of 4.9 cm in wrist-neutral and 5.3 cm in 30 degrees wrist extension. Mean forearm shortening of 3 or 4 cm had a near-complete loss of FDP SMF and TPF in wrist-neutral/wrist extension, respectively. With ∼5 cm shortening, there was a complete loss of fingertip touchdown. Surgeons should consider the influence of forearm shortening on the FDPs and contemplate flexor tendon shortening or alternative reconstructions as indicated.

Bilateral hand dystonia following high-velocity thrust manipulation: a case report.

Thrust manipulation is one of the most commonly used techniques for managing musculoskeletal pain in clinical practice. This involves the application of a high-velocity, low-amplitude force directed to the joints with the intent of achieving joint cavitation. This current case report describes a female in her mid-20s who presented with excessive bilateral and involuntary hand muscle contractions after bilateral thrust manipulation. Dystonia appeared both at rest and during voluntary movements but was aggravated by actions such as finger flexion or spreading and disappeared during sleep. A diagnosis of complex regional pain syndrome (CRPS) type I combined with dystonia was made. Prednisolone administered between 2 and 5 weeks after symptom onset significantly reduced CRPS symptoms, but intramuscular botulinum toxin injection 5 weeks after symptom onset was ineffective at controlling her symptoms. Seven weeks after symptom onset, the patient was administered 2 mg trihexyphenidyl oral twice a day, 2.5 mg diazepam oral twice a day and 5 mg baclofen oral three times a day for 1 month and this significantly reduced dystonia, but complete resolution was not achieved. Clinicians should be aware that dystonia is a rare complication of thrust manipulation.

A confounding pediatric spinal cord injury: Anterior, central, or both?

Pediatric spinal cord injury (SCI) most commonly affects the cervical region. Central cord syndrome most often occurs in the lower cervical injury due to hyperextension injury, while anterior cord syndrome is primarily due to vascular infarction after hyperextension injury. An unusual case of a pediatric patient who physically presented with central cord syndrome but radiologically had evidence of anterior spinal artery syndrome is described. A two-year-old male presented after a fall from three feet with flaccid upper extremities and dysesthesias but maintained functional strength in bilateral lower extremities. Although his clinical presentation was that of central cord syndrome, he was found to have an anterior spinal artery infarct spanning from C2-T3 with a ligamentous injury at C3 and an incidental finding of Chiari I malformation on MRI. Given the negative evaluation for a cardiac or hematologic source of embolus and normal angiography, it was theorized that compression of vertebral arteries by previously undiagnosed Chiari I malformation in the setting of trauma could have made the patient more vulnerable to this complication. During inpatient rehabilitation, he regained scapular movement and shoulder flexion. However, he regained distal movement in supination, wrist extension, and finger flexion instead of the more usual proximal-to-distal motor recovery observed in SCI. While he had a relative sparing of strength in his legs, he had impaired proprioception and balance, leading to gait impairment. This case highlights the complexity of pediatric cervical SCI diagnosis and prognostication. While classic SCI subtypes are well described, many pediatric and adult patients will present and recover in unexpected ways. All with SCI should be evaluated thoroughly for common etiologies and transitioned to rehabilitation therapies to assist in recovery.

Targeted Muscle Reinnervation in the Upper Arm: A Functional Anatomical Study

BackgroundThe aim of this study was to accurately locate the neural fascicle controlling hand movement in the upper arm, to enhance expression of motor intention after targeted muscle reinnervation. MethodsThe right sides of the median, ulnar and radial nerves were dissected from distal to proximal in 6 fresh cadaver specimens. The sectional location and diameter of the functional fascicle were measured at 10 and 20 cm below the acromion. The diameter of the main muscle branches of muscle reinnervation target muscles was measured. ResultsThe median nerve branch of finger and wrist flexion was mainly located between the 9 and 12 o’clock positions in the plane 10 and 20 cm below the acromion, where the diameter of the nerve fascicle was 2.07 and 2.04 mm, respectively. The ulnar nerve branch of finger and wrist flexion was mainly located between the 8 and 12 o’clock positions, with a diameter of respectively 1.80 and 1.99 mm. The radial branch of finger and wrist extension was mainly located between the 10 and 2 o’clock positions in the plane 10 cm below the acromion and between 6 and 12 o’clock in the plane 20 cm below the acromion, with a diameter of respectively 2.57 and 3.03 mm. ConclusionsThe nerve fascicles innervating the flexor and extensor fingers were distributed in relatively constant regions of the median, ulnar and radial nerve trunks, and their diameters closely matched the muscle branches of the target muscle.

Effects of firefighters’ protective gloves on physiological responses, psychological responses, and manual performance in a cold environment

This study aimed to investigate the effects of firefighters' protective gloves on physiological responses, psychological responses, and manual performance in a cold environment through human trials. Twelve participants wearing firefighter protective equipment were exposed to a 16 °C environment, while their hands were exposed to a small chamber of 0 °C with (FPG) and without (CON) firefighting protective gloves. During the trials, physiological responses (core temperature (Tc), the mean skin temperature (Tsk), and heart rate (HR)), psychological responses (thermal sensation vote (TSV) and pain sensation vote (PSV)), and manual performance (handgrip strength, manual dexterity, maximum finger flexion, and tactile sensitivity)) were obtained. The results indicated a significant difference (p < 0.05) between FPG and CON regarding Tsk. Furthermore, pain sensation occurred when the mean skin temperature of the hand was between 15 °C and 20 °C. Gloves significantly (p < 0.05) reduced handgrip strength, manual dexterity, and tactile sensitivity in the cold exposure. This study provides fundamental knowledge for cold strain assessment and high-performance protective glove development with the potential to improve firefighters’ safety and health.

The recovery and independence of elbow flexion and forearm supination after Oberlin II transfer in brachial plexus injuries: a long term follows up study.

The Oberlin II double fascicular nerve transfer has been evaluated extensively for objective outcomes for elbow flexion in brachial plexus injuries (BPI). However, there is limited information available on the recovery pattern of supination and patient-reported activity in the long-term. Our study aimed to assess the functional results with a minimum of five years of follow-up. We evaluated patients with a minimum of five years after the Oberlin II procedure for post-traumatic BPI. They were evaluated using MRC grading, range of active movements, QuickDASH score and activity to check elbow flexion and forearm supination independent of finger and wrist flexion. 18 out of 26 patients responded with a mean follow-up of 79.4months (range: 61-98). 16 (88.9%) (p < 0.000) patients recovered to achieve active elbow flexion and forearm supination of either MRC grade 3 power or more. The average range of active elbow flexion was 113.9° (range: 0-140°) and active supination was 67.8° (0-90°). Patients who achieved grade 3 flexion or higher were found to regain supination after a delay. The recovery continues even after two years of surgery. The mean QuickDASH score was 21.8 (range: 2.3-63.6). There's a significant inverse correlation between QuickDASH with both flexion and supination (p < .001 and < 0.05). 15 patients (83.3%) could demonstrate a dissociation of elbow and forearm movements from digital and wrist movements. Our study demonstrated reliable functional results with independent elbow flexion, forearm supination and acceptable patient-reported outcomes for Oberlin II procedure in BPI.

Soft pneumatic actuators for pushing fingers into extension

BackgroundCompliant pneumatic actuators possess many characteristics that are desirable for wearable robotic systems. These actuators can be lightweight, integrated with clothing, and accommodate uncontrolled degrees of freedom. These attributes are especially desirable for hand exoskeletons, where the soft actuator can conform to the highly variable digit shape. In particular, locating the pneumatic actuator on the palmar side of the digit may have benefits for assisting finger extension and resisting unwanted finger flexion, but this configuration requires suppleness to allow digit flexion while retaining sufficient stiffness to assist extension.MethodsTo meet these needs, we designed an actuator consisting of a hollow chamber long enough to span the joints of each digit while sufficiently narrow not to inhibit finger adduction. We explored the geometrical design parameter space for this chamber in terms of shape, dimensions, and wall thickness. After fabricating an elastomer-based prototype for each actuator design, we measured active extension force and passive resistance to bending for each chamber using a mechanical jig. We also created a finite element model for each chamber to enable estimation of the impact of chamber deformation, caused by joint rotation, on airflow through the chamber. Finally, we created a prototype hand exoskeleton with the chamber parameters yielding the best outcomes.ResultsA rectangular cross-sectional area was preferable to a semi-obround shape for the chamber; wall thickness also impacted performance. Extension joint torque reached 0.33 N-m at a low chamber pressure of 48.3 kPa. The finite element model confirmed that airflow for the rectangular chamber remained high despite deformation resulting from joint rotation. The hand exoskeleton created with the rectangular chambers enabled rapid movement, with a cycle time of 1.1 s for voluntary flexion followed by actuated extension.ConclusionsThe developed soft actuators are feasible for use in promoting finger extension from the palmar side of the hand. This placement utilizes pushing rather than pulling for digit extension, which is more comfortable and safer. The small chamber volumes allow rapid filling and evacuation to facilitate relatively high frequency finger movements.

Functional Electrical Stimulation and Brain-Machine Interfaces for Simultaneous Control of Wrist and Finger Flexion.

Brain-machine interface (BMI) controlled functional electrical stimulation (FES) is a promising treatment to restore hand movements to people with cervical spinal cord injury. Recent intracortical BMIs have shown unprecedented successes in decoding user intentions, however the hand movements restored by FES have largely been limited to predetermined grasps. Restoring dexterous hand movements will require continuous control of many biomechanically linked degrees-of-freedom in the hand, such as wrist and finger flexion, that would form the basis of those movements. Here we investigate the ability to restore simultaneous wrist and finger flexion, which would enable grasping with a controlled hand posture and assist in manipulating objects once grasped. We demonstrate that intramuscular FES can enable monkeys with temporarily paralyzed hands to move their fingers and wrist across a functional range of motion, spanning an average 88.6 degrees at the metacarpophalangeal joint flexion and 71.3 degrees of wrist flexion, and intramuscular FES can control both joints simultaneously in a real-time task. Additionally, we demonstrate a monkey using an intracortical BMI to control the wrist and finger flexion in a virtual hand, both before and after the hand is temporarily paralyzed, even achieving success rates and acquisition times equivalent to able-bodied control with BMI control after temporary paralysis in two sessions. Together, this outlines a method using an artificial brain-to-body interface that could restore continuous wrist and finger movements after spinal cord injury.

Effectiveness of mixed reality-based rehabilitation on hands and fingers by individual finger-movement tracking in patients with stroke

BackgroundMixed reality (MR) is helpful in hand training for patients with stroke, allowing them to fully submerge in a virtual space while interacting with real objects. The recognition of individual finger movements is required for MR rehabilitation. This study aimed to assess the effectiveness of updated MR-board 2, adding finger training for patients with stroke.MethodsTwenty-one participants with hemiplegic stroke (10 with left hemiplegia and 11 with right hemiplegia; nine female patients; 56.7 ± 14.2 years of age; and onset of stroke 32.7 ± 34.8 months) participated in this study. MR-board 2 comprised a board plate, a depth camera, plastic-shaped objects, a monitor, a palm-worn camera, and seven gamified training programs. All participants performed 20 self-training sessions involving 30-min training using MR-board 2. The outcome measurements for upper extremity function were the Fugl–Meyer assessment (FMA) upper extremity score, repeated number of finger flexion and extension (Repeat-FE), the thumb opposition test (TOT), Box and Block Test score (BBT), Wolf Motor Function Test score (WMFT), and Stroke Impact Scale (SIS). One-way repeated measures analysis of variance and the post hoc test were applied for the measurements. MR-board 2 recorded the fingers’ active range of motion (AROM) and Dunnett’s test was used for pairwise comparisons.ResultsExcept for the FMA-proximal score (p = 0.617) and TOT (p = 0.005), other FMA scores, BBT score, Repeat-FE, WMFT score, and SIS stroke recovery improved significantly (p < 0.001) during MR-board 2 training and were maintained until follow-up. All AROM values of the finger joints changed significantly during training (p < 0.001).ConclusionsMR-board 2 self-training, which includes natural interactions between humans and computers using a tangible user interface and real-time tracking of the fingers, improved upper limb function across impairment, activity, and participation. MR-board 2 could be used as a self-training tool for patients with stroke, improving their quality of life.Trial registration number: This study was registered with the Clinical Research Information Service (CRIS: KCT0004167).

Skin Conformal Force Myography Based on Laser Induced Graphene Strain Sensors

Myography – the measurement and recording of muscular activity – finds applications across diverse fields, such as biomechanics, clinical neurophysiology or electrodiagnostic medicine, rehabilitation, sports science, and human-machine interaction.1 Non-invasive myography methods include surface EMG (sEMG, where electrodes are placed on the skin to measure electrical signals during muscle actuation) and force myography (FMG). While sEMG is more broadly explored than FMG, it suffers from limited resolution, signal crosstalk, and skin impedance issues.2 sEMG requires proper skin preparation and electrode placement in order to reduce skin impedance and collect accurate data, making it difficult for home use by general public.3 Furthermore, if one is interested in translating the sEMG signal to muscle forces applied or actions done, as most applications are, the signal needs to be of high quality collected at high sampling rates and needs to be heavily processed.4 On the other hand, FMG measures the position or movement of a limb based on changes in stiffness of the corresponding musculotendinous complex against the default state.5 It offers an attractive alternative to sEMG due to direct measurement of force, user-friendly and less sensitivity to skin impedance, reduced cross talk and robustness in dynamic environments, and high compatibility with prosthetics and exoskeletons.6 While there has been significant progress in FMG devices, existing platforms are still bulky and restrictive to the user.5 A highly flexible and skin conformal sensor system is needed to improve the system's wearability and its integration into other components such as prosthetics. To achieve skin conformality in wearable devices, laser induced graphene (LIG) has emerged as a suitable material owing to its ease of fabrication, cost-effective materials, and tunable properties.7 To the best of our knowledge, skin conformal FMG sensors, especially based on LIG have not been explored. In this work, we developed a skin conformal FMG wearable device based on LIG, capable of continuous strain measurement across the circumference of the forearm for gesture recognition. LIG writing parameters are optimized to obtain a 100-micron highly fibrous film enabling easier transfer. After creating LIG on polyimide, it is transferred onto medical grade polyurethane (MPU) to obtain highly skin conformal and stretchable devices. The sensor system consists of an array of nine individual strain sensors, designed to be placed along the circumference of the forearm. Each strain sensor is connected to an integrated wireless readout system which constantly measures their resistance. Different gestures are performed by the user with the sensor system worn on the forearm. Gestures include individual finger flexions, wrist movements, wrist clenches, and forearm pronation/supination. Upon muscle actuation, each sensor experiences a different strain profile depending on its location with respect to the actuated muscle group. The temporal data associated with each action is analyzed to extract features for training a machine learning (ML)-based classifier. Using the ML model, the system can successfully distinguish among various gestures with a high accuracy (> 97%). Further performance improvement can be achieved by increasing the density of sensors and integrating other piezoresistive materials with LIG to enhance the strain sensitivity. Future work also includes integration with other wearable sensors for simultaneous recording of temperature, pH, and metabolites to achieve a multisensory system for improved health monitoring. References 1 D. F. Stegeman, J. H. Blok, H. J. Hermens and K. Roeleveld, Journal of Electromyography and Kinesiology, 2000, 10, 313–326.2 A. Ranavolo, M. Serrao and F. Draicchio, Front Neurol, 2020, 11, 572069.3 M. L. Delva, K. Lajoie, M. Khoshnam and C. Menon, Biomed Eng Online, 2020, 19, 1–18.4 D. Staudenmann, K. Roeleveld, D. F. Stegeman and J. H. van Dieen, Journal of Electromyography and Kinesiology, 2010, 20, 375–387.5 Z. G. Xiao and C. Menon, Sensors 2019, Vol. 19, Page 4557, 2019, 19, 4557.6 A. Radmand, E. Scheme and K. Englehart, 2016, 53, 443–456.7 R. Ye, D. K. James and J. M. Tour, , DOI:10.1021/acs.accounts.8b00084.

Biological conduits based on spider silk for reconstruction of extended nerve defects.

The availability of appropriate conduits remains an obstacle for successful reconstruction of long-distance nerve defects. In previous sheep trials, we were able to bridge 6 cm nerve gaps with nerve conduits based on spider silk fibers with full functional outcomes. Here, we describe the first application of spider silk for nerve repair inhumans. Four patients with extended nerve defects (>20 cm) underwent nerve reconstruction by interposition of conduits that were composed of spider silk fibers contained in autologous veins. The longitudinal luminal fibers (approx.2500 fibers per graft) consisted of drag line silkfrom Trichonephila spiders. All patients were evaluated between 2and 10 years postreconstruction, clinically, and byneurography. In all patients, primary wound healing and no adverse reactions to the implanted spider silk material wereobserved. Patients regained the following relevant functions: protective sensibility, full flexor function with near-normal grasp and powerful function after microvascular gracilis muscle transfer, and key grip function and gross finger flexion after additional tenodesis. One patient with sciatic nerve reconstruction developed protective sensibility of the lower leg, foot, and gait, enabling normal walking and jogging. No neuroma formation or neuropathic or chronic pain occurred in any of the patients. For patients with extended peripheral nerve defects in the extremities, use of conduits based on spider silk fibers offers the possibility of restoring sensory function and protection from neuroma. This kind of nerve bridges provides new perspectives for the reconstruction of complex and long-distance nerve defects.

Extensor Carpi Radialis Brevis Tendon Transfer for Thumb and Finger Flexion Reconstruction after Failed Extensor Carpi Radialis Brevis Motor Branch Transfer in a Tetraplegic Patient.

Distal nerve transfers can restore precise motor control in tetraplegic patients. When nerve transfers are not successful, tendon transfers may be used for subsequent reconstruction. In this case, an extensor carpi radialis brevis (ECRB) tendon transfer was used to restore thumb and finger flexion following an unsuccessful ECRB to anterior interosseous nerve transfer in a young tetraplegic patient. Twelve months following tendon transfer, the patient demonstrated functional grip and pinch strength and was using both hands for daily activities. Level of Evidence: Level V (Therapeutic).

Ring-Embedded Finger Over Proximal Interphalangeal Joint with Preserved Neurovascularization: A Case Report and Literature Review.

We present a unique case of a 45-year-old man with his right middle finger embedded with rings. Limited finger flexion was noted because of flexor tendon injury caused by the dorsal migration of the embedded ring through joint. The rings were removed under anesthesia, resulting in the resolution of swelling and recover of osseous structure. Follow-up examinations revealed no residual edema or numbness, indicating preserved neurovascularization, despite the dorsal migration of the ring. Our unique case reveals continuous finger ring migration without compromising neurovascular bundles, with review of 30 cases emphasizing the importance of psychiatric consultation. Timely intervention yielded nearly half of patients achieving full recovery.

Central Tendon Tenotomy for Management of Extrinsic Extensor Tightness of the Hand: Surgical Technique and Case Reports.

We present a 67-year-old woman with long finger extrinsic extensor tightness and a 56-year-old man with limited index finger flexion due to extrinsic extensor tightness secondary to tendon transfers for radial nerve palsy. Both patients underwent prior surgical procedures that led to limited range of motion (ROM). Subsequently, they elected for central tendon tenotomy (CTT), which demonstrated postoperative ROM improvement and satisfactory patient outcomes. Surgical management of extrinsic extensor tendon tightness of the hand is generally addressed by performing tenolysis to improve tendon excursion. We present a novel and simple technique of CTT with pertinent anatomy, descriptive cases, and a cadaveric video.

The Influence of Hand Dimensions on Finger Flexion during Lower Paleolithic Stone Tool Use in a Comfortable Grip

Considering the biomechanical and cognitive aspects involved in tool manipulation, hand size emerges as a critical factor. Males, on average, exhibit greater grip strength attributed to larger hand dimensions. Beyond mere physical factors, cognitive components tied to visuospatial abilities also influence stone tool use. However, the intricate relationship between hand size, grip strength, and ergonomic patterns necessitates further exploration. Here, we study the ergonomic pattern of phalanx flexion during the manipulation of Lower Paleolithic stone tools (choppers and handaxes) to understand the nuanced interplay between hand dimensions and grasping behaviors in Lower Paleolithic stone tool use. The static hand posture during the comfortable grasping of each tool is measured using a motion capture hand glove. Flexions are measured at the metacarpophalangeal joint, the proximal interphalangeal joint and the distal interphalangeal joint of each finger. Our investigation into Lower Paleolithic stone tool manipulation reveals gender-based differences in phalanx flexion, with hand dimensions showing correlation only in pooled samples. However, these associations diminish when analyzing males and females separately. This study suggests a minimal link between hand size and grasping behavior within our sample, hinting at the influence of cognitive, behavioral, and motor factors. Exploring lifestyle and psychometric profiles could provide further insights. In the context of early human technology, our results prompt considerations on the evolution of the hand-tool interaction system, linking our tool-dependent culture to our phylogenetic history.

Enhanced functionalization of nonwoven fabric by spray coating AgNPs/CNTs solution prepared by a one-step method

The convergence of nanotechnology and textile engineering has propelled the development and performance enhancement of multifunctional smart materials across various applications. In this study, a one-step method was used to synthesize a multifunctional smart textile by anchoring silver nanoparticles (AgNPs) onto multi-walled carbon nanotubes (CNTs) and spray coating them onto nonwoven fabric. Incorporating CNTs not only enhanced the conductivity, but also improved the heating efficiency of the resulting fabric, which can increases comfort in cold environments through electric heating. The incorporation of AgNPs contributed to the fabric’s photothermal capability. The photothermal conversion efficiency reached 89.7 % under 100 mW/cm2 illumination, resulting in a temperature of 45.0 °C at a current of 1.0 A. The fabric demonstrated exceptional piezoresistive and strain-sensing capabilities with a response time of only 359 ms under a pressure of 3.25 kPa. In addition, the fabric was able to detect subtle physiological signals, such as the wearer’s pulse, finger flexion, and spinal bending while also monitoring environmental humidity in real time. This research not only advances smart textile technology, but also addresses unique challenges to the one-step preparation of CNTs and AgNPs on nonwoven fabric, thus enabling the design and manufacture of innovative materials with tailored functionalities. These advancements will bear significant impacts on electric heating, photothermal applications, and personal wearable strain sensing in textiles.

Highly sensitive and easy-to-attach wearable sensor for measuring finger force based on curvature changes in an ellipse-shaped finger ring

Technologies for digitizing worker actions to enhance human labor tasks, mitigate accidents, and prevent disabling injuries have garnered significant attention. This study focuses on monitoring the force exerted by the fingers and developing a wearable fingertip force sensor based on a simple elliptical ring structure in conjunction with a commercially available resistive bend sensor. Resembling a ring accessory, the sensor is easy to attach and detach, and exhibits high sensitivity, with a resistance change of approximately 9% for a fingertip load of 1 N. Furthermore, to mitigate crosstalk during finger flexion, we propose a combined configuration employing this ring-shaped sensor alongside another sensor designed for measuring and rectifying finger flexion angles. Additionally, we introduce an empirically derived fitting function and a straightforward calibration procedure to extract the function’s parameters. The proposed system achieves an average RMS error of 0.53 N for force estimations of approximately 5 N, even during finger flexion and postural changes.