Mathematical analysis in the design of digital artery-based V-Y advancement flap in treating proximal interphalangeal joint flexion contracture.

BACKGROUND: The digital artery-based V-Y advancement flap is a widely used flap for soft tissue coverage in the treatment of flexion contracture of the proximal interphalangeal (PIP) joint. A standard method for the flap design and a mathematical method to predict the advance distance have not been well established. In this study, we proposed a simplified method for the design of V-Y advancement flaps based on digital arteries and used a geometric model to predict the advance distance for the flexion contracture correction surgery. METHODS: According to the general concept of hand flap design and law of cosine, we proposed three principles in the design of the digital artery-based V-Y advancement flap that should be followed. Since 2021 to 2022, finger geometric data of 120 fingers (index, middle, ring, and small fingers) from 30 healthy participants were collected and analysed to evaluate the necessary advance distance and flap tip angle for PIP flexion contracture correction of different fingers by our flap design method. RESULTS: The middle finger needed a significantly longer advance distance compared to other fingers in the same degree flexion contracture correction. The ring finger had the largest length-to width ratio and smallest flap tip angle among the four fingers in the V-Y flap design. No vertical scar crossed the flexion creases and flap tip angle < 20° was found in the tentative V-Y flap design for the 120 fingers. CONCLUSIONS: Our flap design method provides a proper advance distance and flap length-to-width ratio without common skin complications in the flap design for PIP flexion contracture of index, middle, ring and small fingers. This geometric model provides a mathematical basis for prediction of advance distance and flap tip angle in the design of a digital artery-based V-Y advancement flap.

Surface plasmon polariton assisted near perfect light absorption from corrugated metal-insulator-metal structure exploiting lossy metal films.

We propose and demonstrate a lithography-free self-assembled corrugated Cr/TiO2/Cr metal-insulator-metal (Cr-cMIM) structure on silica opal substrates for broadband near perfect light absorption applications. Our optimal Cr-cMIM structure have reached a spectral average absorption rate above 98% over the visible wavelength range. We carried out numerical calculations to simulate the interaction between the incident light and the Cr-cMIM structure. The simulated absorption spectra qualitatively reproduced the experimental results. Detailed analysis of the simulation results indicates that the corrugation of the Cr layers successfully couples the incident light with the localized surface plasmon polariton. The incorporation of the surface plasmonic excitation and the intrinsic ohmic dissipation of the Cr layers results in the broadband near perfect light absorption over the visible wavelength range.

What Are the Key Factors of Functional Outcomes in Patients with Spinopelvic Dissociation Treated with Triangular Osteosynthesis?

For patients with spinopelvic dissociation (SPD), triangular osteosynthesis is the current method for the fixation of the posterior pelvis. This study aimed to assess the recovery process and radiographic parameters associated with the functional outcomes in patients with SPD treated by triangular osteosynthesis. We collected data from 23 patients with SPD. To investigate the key aspect regarding the functional outcomes of these patients, we measured pre- and post-operative parameters, and a statistical analysis adjusted for age, gender, and time windows was used. The radiographic displacement measurement in the pre-operative period showed that the EQ-5D-5L increased by 2.141 per outlet ratio unit. The EQ-5D-5L increased by 1.359 per inlet ratio unit and 1.804 per outlet ratio during the postoperative period. The EQ-VAS increased significantly only with the inlet ratio in the postoperative period (1.270 per inlet ratio). A vertical reduction in SPD during the surgery can achieve more satisfactory outcomes than a horizontal anatomical reduction, in which the horizontal displacement causes inferior functional outcomes.

A 0.8-µW and 74-dB High-Pass Sigma-Delta Modulator With OPAMP Sharing and Noise-Coupling Techniques for Biomedical Signal Acquisition.

This work presents a third-order high-pass sigma-delta modulator (HPSDM) for biomedical signal acquisition. The operational amplifier (op-amp) sharing and noise-coupling techniques are adopted to reduce the required quantity of op-amps and add a noise-shaping order, which can achieve low power consumption and high resolution. A novel switched-capacitor architecture is proposed to suppress the increasing in-band noise and alleviate the circuit sensitivity to capacitor mismatch in the high-pass integrator. The proposed HPSDM was fabricated in a 0.18-µm standard CMOS process. Measurement results reveal that the proposed HPSDM has a signal-to-noise and distortion ratio (SNDR) of 75.26/74 dB in 200 Hz bandwidth and consumes 1.52/0.8 µW under 1.2/1 V supply voltage, which can achieve a peak Schreier Figure-of-Merit of 156.45/157.98 dB and a peak Walden FoM of 0.802/0.488 pJ/conv.

High-Pass Sigma-Delta Modulator With Techniques of Operational Amplifier Sharing and Programmable Feedforward Coefficients for ECG Signal Acquisition.

A high-pass sigma-delta modulator (HPSDM) is proposed for electrocardiography (ECG) signal acquisition system. The HPSDM is implemented using operational amplifier (op-amp) sharing and programmable feedforward coefficients. The op-amp sharing is adopted to reduce the quantity of amplifiers because they dominate the power consumption of the HPSDM. In addition, given that the magnitude of the ECG is dependent on different persons, programmable feedforward coefficients are utilized to extend the dynamic range of the HPSDM to fit the actual application. The proposed HPSDM is fabricated in a 0.18-µm standard CMOS process. Measurement results reveal that the proposed HPSDM has a signal-to-noise and distortion ratio (SNDR) of 54.5 dB and a power consumption of 2.25 µW under a 1.2 V supply voltage and achieves a figure of merit (FoM) of 12.96 pJ/conv. Moreover, the proposed HPSDM has an SNDR of 64.8 dB and a power consumption of 5.2 µW under a 1.8 V supply voltage and achieves a FoM of 9.15 pJ/conv due to the op-amp sharing technique. Under the 1.2 V and 1.8 V supply voltages, the dynamic range of the HPSDM is extended to approximately 12 dB due to the technique of programmable feedforward coefficients.