Overview and management of complications after digital replantations.

The main complications after digital replantation are discussed in this review article. These complications include vascular compromise, infection, partial necrosis, delayed union or nonunion, atrophy and so on. The countermeasures for these complications are reviewed and the authors' methods are also introduced and discussed.

Relation of digital arterial dysfunction to alternative frequency weightings of hand-transmitted vibration.

This study compared the relative performance of alternative frequency weightings of hand-transmitted vibration (HTV) to predict the extent of cold-induced vasoconstriction in the digital arteries of HTV workers. The cold response of digital arteries was related to measures of daily vibration exposure expressed in terms of r.m.s. acceleration magnitude normalised to an 8-h day, frequency weighted according to either the frequency weighting Wh defined in international standard ISO 5349-1:2001 (Ah(8) in ms-2 r.m.s.) or the hand-arm vascular frequency weighting Wp proposed in the ISO Technical Report 18570:2007 (Ap(8) in ms-2 r.m.s.). The measure of daily vibration exposure constructed with the frequency weighting Wp (Ap(8)) was a better predictor of the cold response of the digital arteries in the HTV workers than the metric derived from the conventional ISO frequency weighting Wh (Ah(8)). This finding suggests that a measure of daily vibration exposure constructed with the vascular weighting Wp, which gives more weight to intermediate- and high-frequency vibration (31.5-250 Hz), performed better for the prediction of cold induced digital arterial hyperresponsiveness than that obtained with the frequency weighting Wh recommended in ISO 5349-1 which gives more importance to lower frequency vibration (≤16 Hz).

Mini-Shaped Kiss Flap Design for Palmar and Digital Soft-Tissue Resurfacing.

BACKGROUND: Although palmar and digital soft-tissue resurfacing with intrinsic flaps may provide functional and aesthetic reconstruction, the donor site may result in a tight closure or need for a skin graft once the flap is raised. In this series, the "mini-shaped kiss flap" was used to increase the resurfacing efficiency and preserve hand function. METHODS: The mini-shaped kiss flaps, based on common palmar digital arteries (eg, princeps pollicis artery and ulnar palmar digital artery), were developed for the resurfacing of distal or proximal finger areas. The tiny skin paddles were "kissed" together and transferred as pedicled in proposed dimensions and shape. The flap size, donor/recipient site, perforator source, whether free or pedicled, surgical outcome, and donor-site morbidity were evaluated. RESULTS: Twenty mini-shaped kiss flaps were harvested for the purpose of palmar and digital resurfacing. The flap sizes varied from 3 × 1.2 cm to 5 × 2 cm. All 19 patients, aged 6 to 52 years (mean, 35 years), achieved successful reconstruction without major complications after 6- to 12-month follow-up. CONCLUSIONS: The mini-shaped kiss flap technique exhibited favorable surgical outcomes with excellent color and texture match to the recipient sites. The reverse midpalm, thenar, and hypothenar island flap can be raised at the cost of an unnoticeable linear scar with minimized functional compromise in the donor area. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Fingertip Replantation: Surgical Technique, Tips, and Tricks.

SUMMARY: Replantation of fingertip amputations restores the original tissue and is the ideal treatment to provide the best aesthetic and functional outcome. However, successful fingertip replantation is considered challenging because it requires supermicrosurgery techniques. This article provides a detailed surgical technique for fingertip replantation and the authors' preferences and recommendations. In the authors' experience, the most important factors for successful fingertip replantation are meticulous vascular dissection, reliable arterial repair, and venous anastomosis to avoid postoperative venous congestion. Proximal arterial dissection until pulsatile bleeding is encountered avoids the zone of vascular injury, and is particularly important in crush or avulsion amputations. Distal arterial dissection is performed until undamaged intima is identified. The authors believe anastomosis to the central artery is reliable even in a Tamai zone II amputation. When an arterial defect is present, the authors recommend using a vein graft to anastomose to the central artery. In addition, the authors highly recommend at least one venous anastomosis to avoid postoperative venous congestion. In Tamai zone I, available veins can be found on the palmar side of the pulp. It is important to search directly below the dermis and remove adipose tissue around the vessels to secure space for anastomosis. The authors consider nerve suture in Tamai zone I and II replantations inessential, because spontaneous sensory recovery can be expected. Postoperative management of venous congestion, spasm in artery, and arterial thrombosis are as important as surgery.

Reconstruction of the ulnar artery in Guyon's canal with an arterial graft: Anatomical study.

Ulnar artery thrombosis in Guyon's canal can lead to vascular insufficiency in the fingers. The recommended treatment is resection and reconstruction of the pathological area. A bypass may be necessary, which may be venous or arterial. Arterial bypasses have better long-term patency; however, they are a source of donor-site complications. We carried out an anatomical study on 11 upper limbs and 7 lower limbs from cadavers to identify a technically accessible arterial graft, of a diameter suitable for bypassing the ulnar artery in Guyon's canal and with acceptable scar sequelae (few predicted postoperative complications, discreet size and/or location of scar). Three grafts were considered: anterior interosseous artery, radial recurrent artery and descending genicular artery. The various grafts were dissected and harvested from cadaver specimens, then their lengths and diameters were measured. The diameter of the candidate grafts was compared to the diameter of the distal ulnar artery. The diameter of the descending genicular artery matched the ulnar artery better than the radial recurrent artery or the anterior interosseous artery (103% vs 44% and 67%, respectively). Mean graft length was 6.6 cm. The anatomical configuration of the descending genicular artery allowed Y-shaped bypasses to be performed. Harvesting this artery appears to cause little damage and allows bypasses up to 6 cm to be performed. Despite its smaller diameter making it necessary to perform a microvascular size adjustment, the anterior interosseous artery is a candidate graft because it is long enough (119 mm) and located near the surgical site. LEVEL OF EVIDENCE: V.

The perfusion index as a noninvasive method for monitoring revascularized and replanted digits.

BACKGROUND: Monitoring replanted digits remains a challenging task in microsurgical units. Previous studies have indicated the perfusion index (PI), a parameter directly proportional to the blood flow, might be a useful tool. OBJECTIVE: The PI is evaluated as a monitoring tool in patients with replanted digits. METHODS: This prospective, non-interventional study includes 31 patients with revascularized or replanted digits. After successful revascularization or replantation, the PI and peripheral oxygen saturation of the affected finger and its contralateral equivalent were measured simultaneously. The values were detected by the device Radical-97® Pulse CO-Oximeter® (Masimo Corporation, 52 Discovery, Irvine, CA 92618, USA). RESULTS: The median PI of affected fingers was 3.5±0.56 for revascularized and 2.2±0.8 for replanted fingers. The difference between the PI values of replanted digits and the healthy contralateral side was highly significant (p < 0.0001). The area under the curve in the receiver operating characteristics was 0.92 for a PI difference > 80.49% and predicted a loss of replant with a specificity of 100% and a sensitivity of 75%. CONCLUSION: The assessment of the PI in patients with reperfusion of a vascular compromised digit is a useful tool to continuously monitor peripheral perfusion. The dynamic behavior of the PI is essential to detect perfusion disturbance.

Near-wall hemodynamic parameters of finger arteries altered by hand-transmitted vibration.

BACKGROUND: Sustained exposure to high-level hand-transmitted vibrations may result in angioneurotic disorders, which partly originate from vibration-altered hemodynamics in the finger arteries when repeating these disturbances throughout working life. Hence, the aim of this study is to assess the most relevant hemodynamic descriptors in the digital arteries, determine the relationship between the latter and vibration features, and gain better understanding of the physiological mechanisms involved. METHODS: An experimental setup, mainly comprised of an ultra-high frequency ultrasound scanner and a vibration shaker, was used to image the digital proper volar arteries of the forefinger. Raw ultrasound data were post-processed by custom-made numerical routines to supply a pulsatile fluid mechanics model for computing the hemodynamic descriptors. Twenty-four healthy volunteers participated in the measurement campaign. Classical statistical methods were then applied to the dataset and also the wavelet transform for calculating the signal power in the frequency bands matching cardiac, respiratory, myogenic and neurogenic activities. RESULTS: The artery diameter, the wall shear stress - WSS - and the WSS temporal gradient - WSSTG - were found to be the most relevant descriptors. Vibration-induced WSS was divided by three compared to its basal value whatever the vibration frequency and it was proportional to log2 of the acceleration level. Marked increases in WSSTG when stopping vibration might also lead to adverse health effects. Vibration caused a drop in WSS power for the frequency band associated with the neurogenic activity of the sympathetic nervous system. CONCLUSION: This study may pave the way for a new framework to prevent vibration-induced vascular risk.

The effect of calcium channel blockers on digital ulcers in systemic sclerosis: data from a prospective cohort study.

Digital ulcers (DU) are a common, severe vascular manifestation of systemic sclerosis (SSc) with few effective treatment options. Using data from the Australian Scleroderma Cohort Study (ASCS), we sought to evaluate the effect of calcium channel blockers (CCB) on the treatment and prevention of DU.Using data from 1953 participants, with a median of 4.34 years of follow-up, we used generalised estimating equations to evaluate the clinical characteristics associated with CCB use and ascertain the risk factors for the presence of DU at subsequent study visits. A time-dependent Cox-proportional hazard model was applied to evaluate the risk of future occurrence of DU with CCB use.Sixty-six percent of participants received CCB and patients with a history of DU were more likely to be prescribed a CCB (76.76% vs 53.70%, p < 0.01). CCB use was more frequent in patients with severe complications of DU including chronic DU (OR 1.47, p = 0.02), need for hospitalisation for iloprost (OR 1.30, p = 0.01) or antibiotics (OR 1.36, p = 0.04) and digital amputation (OR 1.48, p < 0.01). Use of CCB was more likely in patients who experienced DU at subsequent study visits (OR 1.32, p < 0.01) and was not associated with a decreased risk of the development of a first DU (HR 0.94, p = 0.65).CCB are frequently used in the management of SSc in the ASCS and their use is associated with severe peripheral vascular manifestations of SSc. However, our results suggest that CCB may not be effective in the healing or prevention of DU.

A Finger Vein Liveness Detection System Based on Multi-Scale Spatial-Temporal Map and Light-ViT Model.

Prosthetic attack is a problem that must be prevented in current finger vein recognition applications. To solve this problem, a finger vein liveness detection system was established in this study. The system begins by capturing short-term static finger vein videos using uniform near-infrared lighting. Subsequently, it employs Gabor filters without a direct-current (DC) component for vein area segmentation. The vein area is then divided into blocks to compute a multi-scale spatial-temporal map (MSTmap), which facilitates the extraction of coarse liveness features. Finally, these features are trained for refinement and used to predict liveness detection results with the proposed Light Vision Transformer (Light-ViT) model, which is equipped with an enhanced Light-ViT backbone, meticulously designed by interleaving multiple MN blocks and Light-ViT blocks, ensuring improved performance in the task. This architecture effectively balances the learning of local image features, controls network parameter complexity, and substantially improves the accuracy of liveness detection. The accuracy of the Light-ViT model was verified to be 99.63% on a self-made living/prosthetic finger vein video dataset. This proposed system can also be directly applied to the finger vein recognition terminal after the model is made lightweight.

An Improved Multimodal Biometric Identification System Employing Score-Level Fuzzification of Finger Texture and Finger Vein Biometrics.

This research work focuses on a Near-Infra-Red (NIR) finger-images-based multimodal biometric system based on Finger Texture and Finger Vein biometrics. The individual results of the biometric characteristics are fused using a fuzzy system, and the final identification result is achieved. Experiments are performed for three different databases, i.e., the Near-Infra-Red Hand Images (NIRHI), Hong Kong Polytechnic University (HKPU) and University of Twente Finger Vein Pattern (UTFVP) databases. First, the Finger Texture biometric employs an efficient texture feature extracting algorithm, i.e., Linear Binary Pattern. Then, the classification is performed using Support Vector Machine, a proven machine learning classification algorithm. Second, the transfer learning of pre-trained convolutional neural networks (CNNs) is performed for the Finger Vein biometric, employing two approaches. The three selected CNNs are AlexNet, VGG16 and VGG19. In Approach 1, before feeding the images for the training of the CNN, the necessary preprocessing of NIR images is performed. In Approach 2, before the pre-processing step, image intensity optimization is also employed to regularize the image intensity. NIRHI outperforms HKPU and UTFVP for both of the modalities of focus, in a unimodal setup as well as in a multimodal one. The proposed multimodal biometric system demonstrates a better overall identification accuracy of 99.62% in comparison with 99.51% and 99.50% reported in the recent state-of-the-art systems.

Double-pivot proper digital artery perforator flap for fingertip reconstruction.

BACKGROUND: Dorsal flap based on proper digital artery perforator has been commonly used in wound coverage of fingertip; yet a small diameter and short length poses a risk of pedicle kinking or occlusion. The present study aims to present our preliminary results of using a double-pivot perforator flap based on the end dorsal branch of proper digital artery to repair finger pulp defect. METHODS: We designed a double-pivot flap based on the end-dorsal perforator branch of proper digital artery, raised from the dorsal aspect of the middle phalanx, with inclusion of both the perforator and a section of the trunk of the artery. This modified procedure forms a pedicle with a larger diameter and length than traditional designs. Twelve patients (12 fingers) each with a soft-tissue defect of the fingertip were successfully treated and followed up in this retrospective study. RESULTS: All the flaps survived without showing any signs of necrosis; three cases presented with transient venous flow disorder, these self-resolving without requiring any additional treatment. At final follow-up (12-33 months, mean 20 months), mean static two-point discrimination on the flap was 7.0 mm (range, 6-9). CONCLUSION: The double-pivot proper digital artery flap serves as a reliable option in fingertip reconstruction offering added benefits of having greater rotation flexibility, a lower risk of vessel kinking or occlusion, and good recovery of cutaneous sensation.

[Methodology and clinical use of superb microvascular imaging in assessing micro-circulation changes of fingertips in systemic sclerosis].

OBJECTIVE: To explore the feasibility of superb microvascular imaging (SMI) in evaluating microcirculation damage of the finger of systemic sclerosis (SSc), and determining the optimal scanning method by assessing the effect of scanning position (finger pulp or nail bed), plane (transverse or sagittal) and Doppler gain on the results. METHODS: In the study, 32 SSc patients and 32 non-SSc volunteers admitted to Peking University Third Hospital from February to October 2022 were included. The SMI image under different gain set (40 dB or 35 dB) of the third fingertip (sagittal scans or transverse scan of nail bed or pulp) of both hands were collected while vascular index (VI) was measured. RESULTS: Non-SSc volunteer presented abundant SMI signal distributed in the third fingertip. Arteriole of nail bed was observed on the dorsal side of the distal phalanx under SMI and gave off multiple vertical branches towards the nail. The arteriole of finger pulp ran parallel to the skin and gave off vertical branches towards the skin distributing subcutaneously as a network. In SSc group, the SMI signal in nail bed and finger pulp was reduced. The arteriole of nail bed and finger pulp was discontinuous and presented as sporadic dots and short rod-like color signal under SMI. The vascular index of the SSc patients was significantly lower than that of the non-SSc controls (P < 0.001). Among different positions and sections, the area under the receiver operating characteristic curve (AUC) of the sagittal plane of nail bed was the highest. Under low gain, the AUC of sagittal plane of nail bed was 0.871, the cut-off value was 5.4%, the sensitivity was 90.6%, and the specificity was 74.2%. Under high gain, the AUC was 0.893, the cut-off value was 14.0%, the sensitivity was 75.0%, and the specificity was 93.6%. Multivariate analysis showed that there was statistical significance on the diagnostic impact of the sagittal plane of nail bed (P < 0.005 for high gain condition; P < 0.05 for low gain condition). CONCLUSION: SMI can be used to evaluate the abnormal changes of vascular in patients with SSc. Using the sagittal scan of nail bed with high gain can evaluate the vascular loss of the fingertip in SSc patient accurately and specifically.

The effect of dobutamine treatment on salvage of digital replantation and revascularization.

PURPOSE: One of the most common causes of a failure after replantation and revascularization surgeries is 'no reflow' from proximal artery that occurs, especially following crush and avulsion injuries. In this study, we aimed to evaluate the effect of dobutamine treatment on salvage of replanted and revascularized digits. METHODS: The patients with no reflow phenomenon detected in the salvage operations of replanted/revascularized digits between the years 2017 and 2020 were included in the study. Dobutamine treatment was infused at a rate of 4 µg·kg-1·min-1 intraoperatively and of 2 µg·kg-1 min-1 postoperatively. Demographic data (age, sex), digit survival rate, ischemia time, and level of injury were retrospectively analysed. Pre-infusion, intraoperative and postoperative values of cardiac index (CI), mean arterial pressure (MAP), and heart rate (HR) were recorded. RESULTS: The phenomenon of 'no reflow' was encountered in 35 digits of 22 patients who underwent salvage surgery due to vascular compromise. The survival rate in the revascularization group was 75%, while it was 42.1% in the replanted digits. Metaphysis level of proximal phalanx was the most common localization for 'no reflow' phenomenon. The least values of CI, MAP and HR to obtain sufficient perfusion in salvaged digits were as follows: 4.2 l.min-1.m-2, 76 mm Hg, and 83 beat·min-1, respectively. CONCLUSIONS: It was demonstrated that dobutamine infusion at a rate of 4 µg·kg-1·min-1 intraoperatively and at 2 µg·kg-1·min-1 postoperatively has favorable effects on the vascular compromise derived from no reflow of proximal artery.

Finger vein recognition method based on ant colony optimization and improved EfficientNetV2.

Deep learning is an important technology in the field of image recognition. Finger vein recognition based on deep learning is one of the research hotspots in the field of image recognition and has attracted a lot of attention. Among them, CNN is the most core part, which can be trained to get a model that can extract finger vein image features. In the existing research, some studies have used methods such as combination of multiple CNN models and joint loss function to improve the accuracy and robustness of finger vein recognition. However, in practical applications, finger vein recognition still faces some challenges, such as how to solve the interference and noise in finger vein images, how to improve the robustness of the model, and how to solve the cross-domain problem. In this paper, we propose a finger vein recognition method based on ant colony optimization and improved EfficientNetV2, using ACO to participate in ROI extraction, fusing dual attention fusion network (DANet) with EfficientNetV2, and conducting experiments on two publicly available databases, and the results show that the recognition rate using the proposed method on the FV-USM dataset reaches The results show that the proposed method achieves a recognition rate of 98.96% on the FV-USM dataset, which is better than other algorithmic models, proving that the method has good recognition rate and application prospects for finger vein recognition.