Proposing the Retrosternal Angle as a Diagnostic Measure for Banana Sternum in Pectus Excavatum.

BACKGROUND/PURPOSE: Anteriorly convex sternum in pectus excavatum, also known as banana sternum (BS), influences decision-making during repair and, especially, the need to cross bars. However, the definition of BS remains subjective. Thus, we aim to propose the retrosternal angle (RSA) as a diagnostic measure for the discrimination of BS. MATERIAL AND METHODS: Retrospective analysis of a cohort of patients who underwent a minimally invasive repair of pectus excavatum (MIRPE) between October 2016 and October 2023 at our Pectus Clinic. Five expert thoracic surgeons individually reviewed their medical photographs and chest CT scans assigning patients to BS or non-BS groups based on consensus (≥4 surgeons). RSA measurements were obtained by an independent thoracic surgeon. RESULTS: Among 283 cases analyzed, 50 (18%) were classified as BS and 233 (82%) as non-BS. No significant differences were found between groups in age (p = 0.62), Haller index (p = 0.11), or Correction index (p = 0.58). However, RSA was significantly lower in the BS group (141.2 ± 8.4° vs. 154.5 ± 10.3°, p < 0.0001). Receiver operating characteristic curve analysis revealed RSA as a reliable predictor of BS (AUC 0.85, p < 0.0001), with a threshold of 148.5° demonstrating 80% sensitivity and 77% specificity. Regarding potential clinical implications, 26/50 (52%) of patients defined as BS underwent bar crossing, compared with 45/232 (19%) of those not considered a BS (p < 0.0001). CONCLUSION: This study proposes an objective metric, the Retrosternal Angle, to assess BS in chest CT scans, with a threshold of 148.5° showing high sensitivity and specificity. External validation of this angle and threshold is warranted in future investigations. TYPE OF STUDY: Retrospective comparative study. LEVEL OF EVIDENCE: III.

'Short Bars Crossed' to Remodel the Entire Chest Wall in Children and Adolescents with Pectus Excavatum.

BACKGROUND: The cross-bar technique of minimally invasive pectus excavatum (PE) correction remains underreported, which is especially true of pediatric patients. We therefore reviewed the experience of a Turkish and an Austrian center. An additional novelty characterizing both pediatric cohorts was the use of short bars. METHODS: In a retrospective study, pediatric PE corrections involving 'short bars crossed' were analyzed for complications and intra-/postoperative outcomes. Cases with two or three bars were included, given that a horizontal third bar was placed whenever considered useful for upper-chest elevation. All bars were fitted with a single stabilizer near the surgical entry point. In the Austrian center, intercostal nerve cryoablation was used for pain management. Descriptive statistics are presented. RESULTS: Seventy-eight patients ≤18 years old were evaluable at the Turkish (n = 56) and Austrian (n = 22) centers. Total median values were 16.2 (IQR: 15.1-17.4) years for age and 4.60 (IQR: 3.50-6.11) for Haller index. Ten mild or moderate complications (12.8%) were observed, including just one revision requirement due to bar migration (1.28%). Intercostal nerve cryoablation (n = 13) was associated with longer surgical procedures at 150 (IQR: 137-171) versus 80 (IQR: 60-100) minutes but with shorter hospital stays, given an IQR of 3-4 days versus 4-5 days. CONCLUSION: 'Short bars crossed'-with a single stabilizer in a ventral position close to the surgical entry point-ensure a wide distribution of forces, protect against bar migration, are safe and effective, and offer stability at an age characterized by growth and physical activity. LEVEL OF EVIDENCE: IV.

Evaluation of cross-bar and parallel-bar techniques in MIRPE surgery in different countries: a multicenter study.

Parallel- and cross-bar techniques are surgical methods used in the pectus excavatum. While the parallel bar is used in many centers, the cross bar is a new technique. The aim of the study is to evaluate the data of centers using cross bar and parallel bar. The aim of this multicenter study is to retrospectively evaluate the data of centers have been using both cross-bar and parallel-bar techniques. 213 parallel bars and 205 cross bars were used. Parallel-bar advantages: the mean patient satisfaction score was 9.40 ± 0.95. Cross-bar advantages: the rate of patients with symmetric deformity was 75.6%, recurrence 0.5%. The mean patient satisfaction score was 9.40 ± 0.95 in operations performed with the parallel-bar technique and 9.13 ± 1.11 in operations performed with the cross-bar technique (p < 0.05). Recurrence was observed in 3.3% of patients undergoing surgery using the parallel-bar technique and 0.5% of patients undergoing surgery using the cross-bar technique (p < 0.04). The cross-bar technique is more advantageous in terms of the recurrence, while second, the parallel-bar technique is associated with greater patient satisfaction. Comparison of data from different countries reveals the differences between patients who have been treated with minimally invasive repair of pectus excavatum and the outcomes of surgery.

Compute in-Memory with Non-Volatile Elements for Neural Networks: A Review from a Co-Design Perspective.

Deep learning has become ubiquitous, touching daily lives across the globe. Today, traditional computer architectures are stressed to their limits in efficiently executing the growing complexity of data and models. Compute-in-memory (CIM) can potentially play an important role in developing efficient hardware solutions that reduce data movement from compute-unit to memory, known as the von Neumann bottleneck. At its heart is a cross-bar architecture with nodal non-volatile-memory elements that performs an analog multiply-and-accumulate operation, enabling the matrix-vector-multiplications repeatedly used in all neural network workloads. The memory materials can significantly influence final system-level characteristics and chip performance, including speed, power, and classification accuracy. With an over-arching co-design viewpoint, this review assesses the use of cross-bar based CIM for neural networks, connecting the material properties and the associated design constraints and demands to application, architecture, and performance. Both digital and analog memory are considered, assessing the status for training and inference, and providing metrics for the collective set of properties non-volatile memory materials will need to demonstrate for a successful CIM technology.

Nernst effect in anisotropic four-terminal topological nodal-line semimetals.

The Nernst effect is the transverse mode of thermoelectric transport, in which a longitudinal thermal gradient induces a transverse current in the conductor while under a perpendicular magnetic field. Here the Nernst effect in a mesoscopic topological nodal-line semimetals (TNLSMs) system of four-terminal cross-bar with the spin-orbit coupling under a perpendicular magnetic field is studied. The Nernst coefficientNcin two non-equivalen connection modes (kz-ymode andkx-ymode) is calculated based on the tight-binding Hamiltonian combined with the nonequilibrium Green's function method. When the magnetic field is absent withφ = 0.0, the Nernst coefficientNc=0is exactly regardless of the temperature. When the magnetic field is not zero, the Nernst coefficient exhibits a series of densely oscillating peaks. The height of peak strongly depends on the magnetic field, and the Nernst coefficient is an even function of the Fermi energyEFsatisfying the symmetrical propertyNc(-EF)=Nc(EF). The Nernst coefficient is also closely related to the temperatureT. When the temperature is very low (orT→0), the Nernst coefficient depends linearly on temperature. In the presence of a strong magnetic field, the Nernst coefficient shows peaks when the Fermi energy crosses the Landau levels. Under the weak magnetic field, the influence of spin-orbit coupling in TNLSMs materials on Nernst effect is very obvious. In the presence of the mass term, thePT-symmetry of the system is destroyed, the nodal ring of TNLSMs is broken and an energy gap will be opened. The Nernst coefficientNchas a large value in the energy gap, which is very promising for the application of the transverse thermoelectric transport.

Pushing the boundaries of minimally invasive repair of pectus excavatum: first experience with a 4-bar technique.

Several modifications to minimally invasive repair of pectus excavatum have been reported to date. Of these, the use of multiple bars was a major development. At present, there are 2 established techniques: cross-bar and parallel bar placement. We used a combination of both parallel and cross-bar techniques in a 25-year-old male patient with deep, Grand-Canyon type pectus excavatum, placing a total of 4 bars and 4 stabilizers. The patient had no complications during the 7 months of postoperative follow-up. We share this case report as the first experience using this modified technique in the literature.

Current Development of Minimally Invasive Repair of Pectus Excavatum (MIRPE).

For decades, open surgical repair was the only available method to treat congenital and acquired chest wall deformities (CWDs). In 1998, D. Nuss described a minimally invasive procedure for surgical repair of Pectus excavatum (PE). Today, the Nuss procedure is performed with increasing frequency worldwide and considered as the "gold standard". After its introduction, the method experienced numerous modifications such as routine thoracoscopy and/or sternal elevation, increasing safety of the procedure. Placement of multiple bars and/or the so called cross-bar technique were introduced to correct complex CWDs. Standardized pain management, the introduction of cryo-analgesia and a standardized postoperative physiotherapy program including deep breathing exercises facilitate the establishment of an enhanced recovery after surgery (ERAS) process. However, the widespread use of the minimally invasive repair of pectus excavatum (MIRPE) procedure has been associated with a significant number of serious complications. Furthermore, several studies report near-fatal complications, not only during bar placement, but also during bar removal. This review focuses upon the most relevant modifications, including recent published surgical techniques of MIRPE, in order to describe current developments in the field.

Single-centre Indian case series using X or cross bar for Nuss procedure in pectus excavatum.

The modified Nuss procedure using two bars lying parallel or non-intersecting is use to correct pectus excavatum with varying degrees of patient satisfaction. This bar placement has its limitation for certain pectus excavatum morphology where the deformity is deep and focal or located below the subxiphoid. We have altered our bar placement so that bars intersects in an X or cross manner for such pectus morphology. We describe the X or cross bar placement and its specific indications based on morphology in a series of five patients from February 2019 until December 2019 with symmetrical focal deformity along the xiphisternum and asymmetric deformity below the xiphoid. The operating time varied from 90 to 120 min. There was no significant postoperative morbidity. They are on follow-up with period ranging from 4 to 15 months from the day of surgery. Early results show the X or cross bar Nuss procedure can be safely performed to achieve a desired long-term morphological correction of symmetric deep focal xiphisternal defects or asymmetric deformity below the xiphoid.

High-Performance Solution-Processed Organo-Metal Halide Perovskite Unipolar Resistive Memory Devices in a Cross-Bar Array Structure.

Resistive random access memories can potentially open a niche area in memory technology applications by combining the advantages of the long endurance of dynamic random-access memory and the long retention time of flash memories. Recently, resistive memory devices based on organo-metal halide perovskite materials have demonstrated outstanding memory properties, such as a low-voltage operation and a high ON/OFF ratio; such properties are essential requirements for low power consumption in developing practical memory devices. In this study, a nonhalide lead source is employed to deposit perovskite films via a simple single-step spin-coating method for fabricating unipolar resistive memory devices in a cross-bar array architecture. These unipolar perovskite memory devices achieve a high ON/OFF ratio up to 108 with a relatively low operation voltage, a large endurance, and long retention times. The high-yield device fabrication based on the solution-process demonstrated here will be a step toward achieving low-cost and high-density practical perovskite memory devices.