Standard Reconstruction Techniques Research Articles

A Well-Balanced Semi-implicit IMEX Finite Volume Scheme for Ideal Magnetohydrodynamics at All Mach Numbers

We propose a second-order accurate semi-implicit and well-balanced finite volume scheme for the equations of ideal magnetohydrodynamics including gravitational source terms. The scheme treats all terms associated with the acoustic pressure implicitly while keeping the remaining terms part of the explicit sub-system. This semi-implicit approach makes the method particularly well suited for problems in the low Mach regime. We combine the semi-implicit scheme with the deviation well-balancing technique and prove that it maintains equilibrium solutions for the magnetohydrostatic case up to rounding errors. In order to preserve the divergence-free property of the magnetic field enforced by the solenoidal constraint, we incorporate a constrained transport method in the semi-implicit framework. Second order of accuracy is achieved by means of a standard spatial reconstruction technique with total variation diminishing property, and by an asymptotic preserving time stepping algorithm built upon the implicit-explicit Runge–Kutta time integrators. Numerical tests in the low Mach regime and near magnetohydrostatic equilibria support the low Mach and well-balanced properties of the numerical method.

MENISCAL ANOMALIES IN CONGENITAL CRUCIATE LIGAMENT DEFICIENCY: EXPERIENCE IN A TERTIARY CHILDREN'S KNEE UNIT

ObjectivesCongenital cruciate ligament deficiency is a rare condition that may occur in isolation or in association with longitudinal limb deficiencies such as fibular hemimelia or proximal femoral focal deficiency. Often anomalies of the menisci and their attachments can be very abnormal and impact on surgical management by standard techniques. Arthroscopic surgical knee reconstruction is undertaken to improve symptomatic instability and/or to stabilise and protect the knee for future planned limb lengthening surgery.The aim of this study is to evaluate the arthroscopic findings of patients undergoing surgery for congenital cruciate ligament deficiency, and specifically to determine the frequency and types of meniscal anatomical variations seen in these cases.MethodsPatients undergoing surgery for congenital cruciate ligament deficiency were identified from a prospectively collated database. Diagnosis was confirmed through review of the clinical notes and imaging. Operative notes and 4K saved arthroscopic images and video recordings for these cases were reviewed.ResultsOver a six-year period (July 2017 – September 2023), 42 patients underwent surgery for congenital ligament deficiency and tibiofemoral instability (45 surgical episodes). Median age of patients at time of surgery was 10 years (range 4 – 17 years). The most frequent diagnosis was congenital longitudinal limb deficiency syndromes in 27 cases, with the most frequent being fibular hemimelia. Isolated congenital ligament deficiency without any other associated extra-articular manifestations occurred in 11 cases. Absence of meniscal root attachments or hypertrophy of meniscofemoral ligaments acting as ‘pseudo-cruciates’ were seen in over 25% of patients. In isolated ACL deficiency these were injured causing onset of instability symptoms and pain following trauma. Often these abnormal structures required addressing to allow surgical reconstruction.ConclusionsOur findings demonstrate that there are often meniscal variations seen in association with congenital absence or hypoplasia of the cruciate ligaments. In these patients hypertrophied meniscofemoral ligaments may act as cruciate-like structures and play a role in providing a degree of sagittal plane stability to the knee. However, when the knee becomes unstable to the point that cruciate ligament reconstruction is indicated, these meniscal variants may often require stabilisation using complex meniscal root repair techniques or variations to standard cruciate ligament reconstruction techniques to accommodate the variant anatomy.

A clinical practice review on process efficiency in autologous breast reconstruction.

Autologous breast reconstruction is considered the gold standard technique for breast reconstruction following mastectomy. Thanks to recent refinements the main focus of surgery has shifted from flaps survival and donor site morbidity to optimal aesthetic outcomes and patients' satisfaction. However, prolonged operative time remains a limiting aspect for many patients and surgeons who aim in improving access to care and outcomes. Process mapping is a quality improvement strategy consisting of the creation of a visual representation of a process to recognize errors, minimize waste and optimize outcomes. It has been effectively applied in abdominal based autologous breast reconstruction in nine papers. The process segments and analysis varied between published papers, but all authors focused on intraoperative process mapping and reported reduced operative times. Additional preoperative and postoperative factors have been studied and are commonly applied to further optimize efficiency (such as preoperative CTA, co-surgery model, flap perfusion evaluation, postoperative monitoring, and ERAS protocol). Although shorter operative times are related to decrease surgical morbidity and faster recovery time, and safety, the aesthetic outcome should remain the main focus in autologous breast reconstruction. In fact, the true ultimate aim should be the achievement of high patient satisfaction.

Attentional Ptycho-Tomography (APT) for three-dimensional nanoscale X-ray imaging with minimal data acquisition and computation time

Noninvasive X-ray imaging of nanoscale three-dimensional objects, such as integrated circuits (ICs), generally requires two types of scanning: ptychographic, which is translational and returns estimates of the complex electromagnetic field through the IC; combined with a tomographic scan, which collects these complex field projections from multiple angles. Here, we present Attentional Ptycho-Tomography (APT), an approach to drastically reduce the amount of angular scanning, and thus the total acquisition time. APT is machine learning-based, utilizing axial self-Attention for Ptycho-Tomographic reconstruction. APT is trained to obtain accurate reconstructions of the ICs, despite the incompleteness of the measurements. The training process includes regularizing priors in the form of typical patterns found in IC interiors, and the physics of X-ray propagation through the IC. We show that APT with ×12 reduced angles achieves fidelity comparable to the gold standard Simultaneous Algebraic Reconstruction Technique (SART) with the original set of angles. When using the same set of reduced angles, then APT also outperforms Filtered Back Projection (FBP), Simultaneous Iterative Reconstruction Technique (SIRT) and SART. The time needed to compute the reconstruction is also reduced, because the trained neural network is a forward operation, unlike the iterative nature of these alternatives. Our experiments show that, without loss in quality, for a 4.48 × 93.2 × 3.92 µm3 IC (≃6 × 108 voxels), APT reduces the total data acquisition and computation time from 67.96 h to 38 min. We expect our physics-assisted and attention-utilizing machine learning framework to be applicable to other branches of nanoscale imaging, including materials science and biological imaging.

Effects of DIEP flap-based breast reconstruction on respiratory function

BackgroundBreast reconstruction (BR) is an essential part of breast cancer treatment, and the DIEP flap is considered the gold standard reconstruction technique, which uses a free abdominal flap. Concerns have been raised regarding the effects of abdominoplasty on respiratory functions. This topic has not been addressed regarding donor-site closure of DIEP flaps. Our aim is to prospectively compare preoperative and postoperative spirometry in patients undergoing DIEP flap-based BR, investigating its impact on respiratory function. Materials and methodsWe enrolled 21 patients who received BR with DIEP flap in our institution, who underwent pulmonary function assessment by spirometry 1 month preoperatively and 1 year postoperatively. We assessed Forced Expiratory Volume in the first second (FEV1), Forced Vital Capacity (FVC), FEV1/FVC ratio, and Peak Expiratory Flow (PEF). Statistical analysis was performed using the paired samples test. ResultsAn improvement in the mean values of all 4 variables was found at 1 year from surgery. Namely, FEV1 improved by 0.1 L with a standard deviation (SD) of 0.39 L, FVC by 0.04 L with SD of 0.627, FEV1/FVC by 2.11 L with SD of 7.85 L, and PEF by 1.2 L with SD of 1.45 L. Only PEF was statistically significant [P = 0.001]. ConclusionOur results suggest that DIEP flap BR does not negatively impact respiratory function. Although further knowledge is required, we confirm the possibility of considering the indication for abdominoplasty and DIEP flap reconstruction in patients with altered and reduced pulmonary function.

Bile Duct Regeneration with an Artificial Bile Duct Made of Gelatin Hydrogel Nonwoven Fabrics.

Although choledochojejunostomy is the standard technique for biliary reconstruction, there are various associated problems that need to be solved such as reflux cholangitis. Interposition with an artificial bile duct (ABD) to replace the resected bile duct maintains a physiological conduit for bile and may solve this problem. This study investigated the usefulness of an ABD made of gelatin hydrogel nonwoven fabric (GHNF). GHNF was prepared by the solution blow spinning method. The migration and activity of murine fibroblast L929 cells were examined in GHNF sheets. L929 cells migrated into GHNF sheets, where they proliferated and synthesized collagen, suggesting GHNF is a promising scaffold for bile duct regeneration. ABDs made of GHNF were implanted in place of resected bile duct segments in rats. The rats were killed at 2, 6, and 12 weeks postimplantation. The implantation site was histologically evaluated for bile duct regeneration. At postoperative 2 weeks, migrating cells were observed in the ABD pores. The implanted ABD was mostly degraded and replaced by collagen fibers at 6 weeks. Ki67-positive bile duct epithelial cells appeared within the implanted ABD. These were most abundant within the central part of the ABD after 6 weeks. The percentages of Ki67-positive cells were 31.7 ± 9.1% in the experimental group and 0.8 ± 0.6% in the sham operation group at 6 weeks (p < 0.05), indicating that mature biliary epithelial cells at the stump proliferated to regenerate the biliary epithelium. Biliary epithelial cells had almost completely covered the bile duct lumen at 12 weeks (epithelialization ratios: 10.4 ± 6.9% at 2 weeks, 93.1 ± 5.1% at 6 weeks, 99.2 ± 1.6% at 12 weeks). The regenerated epithelium was positive for the bile duct epithelium marker cytokeratin 19. Bile duct regeneration was accompanied by angiogenesis, as evidenced by the appearance of CD31-positive vascular structures. Capillaries were induced 2 weeks after implantation. The number of capillaries reached a maximum at 6 weeks and decreased to the same level as that of normal bile ducts at 12 weeks. These results showed that an ABD of GHNF contributed to successful bile duct regeneration in rats by facilitating the cell migration required for extracellular matrix synthesis, angiogenesis, and epithelialization. Impact Statement Development of an artificial bile duct (ABD) enables physiological biliary reconstruction and may solve clinical problems associated with choledochojejunostomy. In this study, we created ABDs with gelatin hydrogel nonwoven fabric and implanted them in place of resected bile duct in rats. We evaluated the process of bile duct regeneration as well as decomposition of the ABD and demonstrated successful regeneration of resected bile duct, highlighting the possibility of this novel biliary reconstruction method to replace choledochojejunostomy.

Deep learning-based reconstruction of virtual monoenergetic images of kVp-switching dual energy CT for evaluation of hypervascular liver lesions: Comparison with standard reconstruction technique

ObjectiveTo investigate clinical applicability of deep learning(DL)-based reconstruction of virtual monoenergetic images(VMIs) of arterial phase liver CT obtained by rapid kVp-switching dual-energy CT for evaluation of hypervascular liver lesions. Materials and MethodsWe retrospectively included 109 patients who had available late arterial phase liver CT images of the liver obtained with a rapid switching kVp DECT scanner for suspicious intra-abdominal malignancies. Two VMIs of 70 keV and 40 keV were reconstructed using adaptive statistical iterative reconstruction (ASiR-V) for arterial phase scans. VMIs at 40 keV were additionally reconstructed with a vendor-agnostic DL-based reconstruction technique (ClariCT.AI, ClariPi, DL 40 keV). Qualitative, quantitative image quality and subjective diagnostic acceptability were compared according to reconstruction techniques. ResultsIn qualitative analysis, DL 40 keV images showed less image noise (4.55 vs 3.11 vs 3.95, p < 0.001), better image sharpness (4.75 vs 4.16 vs 4.3, p < 0.001), better image contrast (4.98 vs 4.72 vs 4.19, p < 0.017), better lesion conspicuity (4.61 vs 4.23 vs 3.4, p < 0.001) and diagnostic acceptability (4.59 vs 3.88 vs 4.09, p < 0.001) compared with ASiR-V 40 keV or 70 keV image sets. In quantitative analysis, DL 40 keV significantly reduced image noise relative to ASiR-V 40 keV images (49.9%, p < 0.001) and ASiR-V 70 keV images (85.2%, p = 0.012). DL 40 keV images showed significantly higher CNRlesion to the liver and SNRliver than ASiR-V 40 keV image and 70 keV images (p < 0.001). ConclusionDL-based reconstruction of 40 keV images using vendor-agnostic software showed greater noise reduction, better lesion conspicuity, image contrast, image sharpness, and higher overall image diagnostic acceptability than ASiR for 40 keV or 70 keV images in patients with hypervascular liver lesions.

An Anatomically Placed Tibial Tunnel does not Completely Surround a Simulated PCL Reconstruction Graft in the Proximal Tibia.

It is hypothesized that anatomic tunnel placement will create tunnels with violation of the posterior cortex and subsequently an oblique aperture that is not circumferentially surrounded by bone. In this article, we aimed to characterize posterior cruciate ligament (PCL) tibial tunnel using a three-dimensional (3D) computed tomography (CT) model. Ten normal knee CTs with the patella, femur, and fibula removed were used. Simulated 11 mm PCL tibial tunnels were created at 55, 50, 45, and 40 degrees. The morphology of the posterior proximal tibial exit was examined with 3D modeling software. The length of tunnel not circumferentially covered (cortex violation) was measured to where the tibial tunnel became circumferential. The surface area and volume of the cylinder both in contact with the tibial bone and that not in contact with the tibia were determined. The percentages of the stick-out length surface area and volume not in contact with bone were calculated. The mean stick-out length of uncovered graft at 55, 50, 45, and 40 degrees were 26.3, 20.5, 17.3, and 12.7 mm, respectively. The mean volume of exposed graft at 55, 50, 45, and 40 degrees were 840.8, 596.2, 425.6, and 302.9 mm3, respectively. The mean percent of volume of exposed graft at 55, 50, 45, and 40 degrees were 32, 29, 25, and 24%, respectively. The mean surface of exposed graft at 55, 50, 45, and 40 degrees were 372.2, 280.4, 208.8, and 153.3 mm2, respectively. The mean percent of surface area of exposed graft at 55, 50, 45, and 40 degrees were 40, 39, 34, and 34%, respectively. Anatomic tibial tunnel creation using standard transtibial PCL reconstruction techniques consistently risks posterior tibial cortex violation and creation of an oblique aperture posteriorly. This risk is decreased with decreasing the angle of the tibial tunnel, though the posterior cortex is still compromised with angles as low as 40 degrees. With posterior cortex violation, a surgeon should be aware that a graft within the tunnel or socket posteriorly may not be fully in contact with bone. This is especially relevant with inlay and socket techniques.

Using the Navier-Cauchy equation for motion estimation in dynamic imaging

&lt;p style='text-indent:20px;'&gt;Tomographic image reconstruction is well understood if the specimen being studied is stationary during data acquisition. However, if this specimen changes its position during the measuring process, standard reconstruction techniques can lead to severe motion artefacts in the computed images. Solving a dynamic reconstruction problem therefore requires to model and incorporate suitable information on the dynamics in the reconstruction step to compensate for the motion.&lt;/p&gt;&lt;p style='text-indent:20px;'&gt;Many dynamic processes can be described by partial differential equations which thus could serve as additional information for the purpose of motion compensation. In this article, we consider the Navier-Cauchy equation which characterizes small elastic deformations and serves, for instance, as a simplified model for respiratory motion. Our goal is to provide a proof-of-concept that by incorporating the deformation fields provided by this PDE, one can reduce the respective motion artefacts in the reconstructed image. To this end, we solve the Navier-Cauchy equation prior to the image reconstruction step using suitable initial and boundary data. Then, the thus computed deformation fields are incorporated into an analytic dynamic reconstruction method to compute an image of the unknown interior structure. The feasibility is illustrated with numerical examples from computerized tomography.&lt;/p&gt;

Surgical Treatment of Marginal Impaction Injuries of The Acetabulum Associated with Posterior Wall Fractures

The procedure is performed with the patient under general anesthesia, placed under traction in either the prone or lateral position with use of a radiolucent flat-top fracture table and fluoroscopic guidance. The Kocher-Langenbeck approach is utilized. The big posterior wall fracture is identified and reflected in order to visualize the joint surface. Subsequently, traction is applied to facilitate visualization of the marginal impaction area(s). With use of an osteotome, the impacted fragments are disimpacted and elevated. The femoral head is utilized as a template for accurate reduction of the impacted fragments to the acetabular joint surface. The resultant subchondral void is assessed and may be grafted with use of a variety of bone graft materials. The 2-level reconstruction technique may also be considered when the surgeon desires to optimize stability of the impacted fragments and maintain anatomical reduction. The big posterior wall fragment is reduced and fixed with use of the standard posterior-wall reconstruction technique. Finally, irrigation and wound closure in layers is performed. Treatment alternatives include either delayed or acute primary total hip arthroplasty in elderly patients >70 years old. Preoperative identification of the marginal impaction is critical because articular incongruency leads to the development of early posttraumatic osteoarthritis. Achieving joint congruency is especially important in the young population in order to avoid an otherwise unnecessary early total hip arthroplasty. Expected radiographic outcomes are excellent or good in 82% of cases, as measured with use of the Matta radiographic score1-3. Expected function outcomes are good to excellent in 67.5% of patients, as measured with use of the Modified Merle d'Aubigné system1-3. Total hip arthroplasty has been reported as a secondary procedure within 2 years postoperatively in 7.6% of patients1-3. Joint irrigation is crucial in order to clarify the details of the fragmentation and facilitate removal of debris. Impacted articular cartilage fragments are often rotated and face away from the femoral head. Utilize osteotomes to elevate the impacted area, taking care to mobilize adequate subchondral bone and the accompanying cartilage in case the 2-level reconstruction technique is needed and can be successfully applied. Utilize the femoral head as a template after traction is released to facilitate anatomical reduction. A 1.6-mm Kirschner wire should be available in case it is needed to temporarily stabilize the impacted fragments. Avoid overstuffing the void with bone graft because this may subsequently hinder successful reduction of the posterior wall fragment. CT = computed tomographyAP = anteroposteriorK wire = Kirschner wirePDS = polydioxanone sutureAVN = avascular necrosis.

Soft Gasket Seal Reconstruction After Endoscopic Endonasal Transtuberculum Resection of Craniopharyngiomas

The expanded endoscopic endonasal approach (EEA) is currently well accepted for a variety of ventral skull base tumors. Such an approach often results in a transdural defect and intraoperative cerebrospinal fluid (CSF) leak, and adequate reconstruction is necessary to prevent postoperative CSF leak and its complications. Reconstruction is usually performed using a variety of materials along with the nasoseptal flap. This work's aim is to describe a new reconstructive technique called the "soft gasket seal" (SGS) in detail and compare it with the standard reconstructive technique at our institution for craniopharyngiomas operated via transtuberculum EEA. A retrospective chart review was achieved to identify patients who underwent transtubercular EEA for craniopharyngioma between 2010 and 2018, by the same neurosurgical and otolaryngology team using either the SGS or standard reconstructive technique. Of 36 patients who met criteria and were considered for analysis, 15 of them underwent SGS reconstruction and 21 had standard reconstruction. There were 16 female (44%) and 20 male (56%) patients. The median age was 42.2 ± 20.9 years. The rate of postoperative CSF leak in the group of patients treated with the standard technique was 14.2% and 6.6% in the SGS group (odds ratio 0.43 [confidence interval 95% 0.007-6.15], P= 0.62). The SGS technique provides a simple reconstructive technique in conjunction with the nasoseptal flap, showing a tendency of lower complications when compared with our standard technique while avoiding donor site morbidity. Such results are encouraging, but further studies are necessary to confirm these findings.

R2 inflation revisited and dark energy corrections

The vacuum $R^2$ model is known to generate a quasi-de Sitter evolution for inflation, using solely the slow-roll assumptions. Using standard reconstruction techniques, we demonstrate that the $f(R)$ gravity which actually realizes the quasi-de Sitter evolution is not simply the $R^2$ model but a deformed $R^2$ model which contains extra terms in addition to the $R^2$ model. We analyze in detail the inflationary dynamics of the deformed $R^2$ model and we demonstrate that the predictions are quite close to the ones of the pure $R^2$ model, regardless the values of the free parameters. Basically the deformed $R^2$ model is also a single parameter inflationary model, exactly like the ordinary $R^2$ model. In contrast to the early-time era, where the deformed $R^2$ model is quite similar to the $R^2$ model, at late times, the phenomenological picture is different. The deformed $R^2$ model describes stronger gravity compared to the ordinary $R^2$ with an effectively smaller effective Planck mass. We propose the addition of an early dark energy term which does not affect at all the inflationary era, but takes over the control of the late-time dynamics at late times. We study in some detail the predicted dark energy era evolution, and we demonstrate that the dark energy corrected deformed $R^2$ model can describe a viable dark energy era, compatible with the Planck constraints on cosmological parameters. Furthermore the model is distinct from the $\Lambda$-Cold-Dark-Matter model, but shows a qualitatively similar behavior.

Deep Learning Reconstruction Helps to Achieve Diagnostic-like Image Quality in MR Radiation Therapy of Brain

Deep Learning Reconstruction Helps to Achieve Diagnostic-like Image Quality in MR Radiation Therapy of Brain

Evaluating a calcium-aware kernel for CT CAC scoring with varying surrounding materials and heart rates: a dynamic phantom study

ObjectivesThe purpose of this study was twofold. First, the influence of a novel calcium-aware (Ca-aware) computed tomography (CT) reconstruction technique on coronary artery calcium (CAC) scores surrounded by a variety of tissues was assessed. Second, the performance of the Ca-aware reconstruction technique on moving CAC was evaluated with a dynamic phantom.MethodsAn artificial coronary artery, containing two CAC of equal size and different densities (196 ± 3, 380 ± 2 mg hydroxyapatite cm−3), was moved in the center compartment of an anthropomorphic thorax phantom at different heart rates. The center compartment was filled with mixtures, which resembled fat, water, and soft tissue equivalent CT numbers. Raw data was acquired with a routine clinical CAC protocol, at 120 peak kilovolt (kVp). Subsequently, reduced tube voltage (100 kVp) and tin-filtration (150Sn kVp) acquisitions were performed. Raw data was reconstructed with a standard and a novel Ca-aware reconstruction technique. Agatston scores of all reconstructions were compared with the reference (120 kVp) and standard reconstruction technique, with relevant deviations defined as > 10%.ResultsFor all heart rates, Agatston scores for CAC submerged in fat were comparable to the reference, for the reduced-kVp acquisition with Ca-aware reconstruction kernel. For water and soft tissue, medium-density Agatston scores were again comparable to the reference for all heart rates. Low-density Agatston scores showed relevant deviations, up to 15% and 23% for water and soft tissue, respectively.ConclusionCT CAC scoring with varying surrounding materials and heart rates is feasible at patient-specific tube voltages with the novel Ca-aware reconstruction technique.Key Points• A dedicated calcium-aware reconstruction kernel results in similar Agatston scores for CAC surrounded by fatty materials regardless of CAC density and heart rate.• Application of a dedicated calcium-aware reconstruction kernel allows for radiation dose reduction.• Mass scores determined with CT underestimated physical mass.

Prelaminated flaps in head and neck cancer reconstructive surgery: A systematic review.

BackgroundPrelamination is a reconstructive technique providing fasciomucosal or composite flaps with low donor‐site morbidity. We conducted a systematic review of retrospective studies to assess the application of prelaminated flaps in reconstructive surgery of head and neck cancer patients, and to evaluate the advantages and disadvantages of this technique.MethodsThis systematic review adhered to the recommendations of the PRISMA (Preferred Reporting Items of Systematic Reviews and Meta‐analysis) 2009 guidelines. A computerized MEDLINE search was performed using the PubMed service of the U.S. National Library of Medicine (www.pubmed.org) and Scopus database (www.scopus.com), running the following search string: “prelamination OR prelaminated AND flap.” Two authors screened the articles, then selected and extracted data on malignancies characteristics, reconstructive techniques, outcomes and complications.ResultsA total of 19 articles were selected and reviewed from 128 identified. Seven of 19 articles were case reports, 12 articles were case series. One‐hundred‐two patients underwent reconstructive treatment by prelamination technique using a wide variety of flaps (92 free, 10 pedicled). The sites of reconstruction were oral cavity (66 floor of the mouth, 3 retromolar trigone, 6 hard palate, 4 cheek, 4 tongue), 8 facial skin (5 of them sited on the nose), 4 oropharyngeal defects, 1 laryngotracheal region. No case of total flap loss was reported. Partial flap loss or shrinkage requiring minor surgical revisions was observed in 18 patients (17.6%). Primary closure of the donor site was achieved in 97 cases (97%) and 3 (3%) required revision surgery of the donor site.ConclusionPrelamination is an effective and versatile technique, with low donor‐site morbidity. Further studies would be needed to investigate the impact on the patient's oncologic outcome. More comparative studies with standard reconstructive techniques are essential to understand when it is worth performing this sophisticated procedure.

The position of urethrovesical anastomosis after robotic radical prostatectomy assessed by MRI predicts early functional recovery: A cohort analyses from a randomized clinical trial

PurposeFunctional and anatomical changes associated with prostate removal coincide with alterations in pelvic structures. Posterior rhabdosphincter reconstruction was designed to improve urinary continence after radical prostatectomy. The aim of this study was to determine magnetic resonance anatomic predictors of urinary recovery after radical prostatectomy, and to assess their relation to the type of reconstruction. Material and MethodsForty patients were randomly selected from a trial (NCT03302169). Two independent radiologists determined the situation of the anastomosis in the pelvis according to MRI performed a month after the radical prostatectomy: vertical situation assessed as the distance to the line coccyx-inferior pubic margin (ACPv) and anteroposterior situation as the distance from the pubis (Distance A), and from the coccyx (Distance B). ResultsThe Pearson correlation of ACPv, Distance A, and B between readers were 0.975, 0.940, and 0.711, p < 0.001. Patients with the reconstruction presented more cephalic situation of the anastomosis (higher ACPv) than patients with standard reconstruction technique. A multivariate analysis was performed including age, BMI, prostate volume, PRRS, and the MRI parameters. ACPv and Distance B were the only two independent predictors of no need for any urinary protection at 6 months after the surgery. ConclusionsThis is the first study that suggests positional differences according to the type of reconstruction after radical prostatectomy related to early urinary recovery. Magnetic resonance measurements to determine anastomosis positioning are reliable and have a strong correlation between readers. Anatomic MRI features are independent predictors of urinary recovery after robotic radical prostatectomy.

Preoperative computed tomography assessment for a deep inferior epigastric perforator (DIEP) flap: a new easy technique from the Bologna experience.

Deep inferior epigastric perforator (DIEP) flap reconstruction is the gold standard reconstructive technique for women undergoing breast cancer surgery. A preoperative computed tomography angiography (CTA)-dedicated protocol and 3D reconstructions are mandatory for correct surgical planning. To evaluate the diagnostic performance of a new preoperative CTA protocol and a new reconstruction method in the assessment of DIEP technique. A total of 263 women (median age 49 years, age range 26-73 years) underwent preoperative CTA examination before DIEP flap breast reconstruction. A CTA-dedicated protocol followed by 3D-reconstructions were performed. Identification, branching pattern, and caliber at origin were assessed for each perforator. Intraoperative findings were the standard of reference. The sensitivity, positive predictive value, and diagnostic accuracy of the preoperative CTA protocol were calculated. In 255/263 (97%) patients, the dominant perforators assessed by CTA resulted adequate for surgical reconstruction. In 260/263 (99%) cases, the imaging localization of the dominant perforators corresponded with those seen intraoperatively (mean errors ≤1 cm). The preoperative CTA imaging sensitivity, positive predictive value, and diagnostic accuracy in determining the localization of perforators were 99% (95% CI 98-100), 100% and 99% (95% CI 98-100), respectively. No statistically significant differences were found between the CTA findings and the surgical findings for the assessment of branching pattern and caliber of the dominant perforators (P < 0.001). The present protocol has demonstrated high accuracy in the CTA imaging assessment of the perforators before DIEP flap reconstruction with high reproducibility between CT and surgical findings.

The current outcomes and future challenges in pediatric vascularized composite allotransplantation.

We review the outcomes and future challenges associated with pediatric vascularized composite allotransplantation, including follow-up data from our bilateral pediatric hand-forearm transplantation. In 2015, the first heterologous pediatric upper extremity hand-forearm transplant was performed at the Children's Hospital of Philadelphia, and in 2019, the first pediatric neck reconstructive transplantation was performed in Poland. The 5-year follow-up of the pediatric upper extremity recipient demonstrates similar growth rates bilaterally, an increase in bone age parallel to chronologic age, and perhaps similar overall growth to nontransplant norms. The pediatric upper extremity recipient continues to make gains in functional independence. He excels academically and participates in various extracurricular activities. Future challenges unique to the pediatric population include ethical issues of informed consent, psychosocial implications, limited donor pool, posttransplant compliance issues, and greater life expectancy and therefore time to inherit the many complications of immunosuppression. Currently, we recommend pediatric vascularized composite allotransplantation (VCA) for bilateral upper extremity amputees, preferably on immunosuppression already, and those patients who would have the most potential gain not available through standard reconstructive techniques while being able to comply with postoperative immunosuppression protocols, surveillance, rehabilitation, and follow-up.

Postoperative Safety and Satisfaction in Patients With Microtia

The reconstructive approach for microtia should employ a surgical technique that reconstructs the atrial anatomy; therefore, multiple surgical techniques have been described, and these have undergone variations due to adaptation by different authors. This study aims to assess the postoperative safety and satisfaction of patients with microtia undergoing surgery with the ear reconstruction technique. A retrospective cohort study was performed in patients undergoing ear reconstruction with costochondral grafts. The patients were treated in the craniomaxillofacial surgery services of hospitals in Mexico and Colombia from 2008 to 2018. All medical records from the entire study population were included, including complete photographic records and informed consents. A descriptive analysis was performed to characterize the clinical variables and complications. Bivariate analysis was performed using Fisher's exact χ2 test to explore the relationship between clinical and demographic variables with respect to complications. A total of 410 patients were followed for a period of 12 to 16months. Only 10% of the sample presented some type of complication. A common complication was dehiscence of the atrial area (23 patients), as well as poor anatomical reproduction (7 patients) due to the collapse of the drainage tubes in the first postoperative phase. No connection was found between the presence of complications and side or type, and no congenital anomalies were found to be associated with microtia (P>.05). The helix and the antihelix were the anatomical areas with greater satisfaction scores. Costochondral cartilage is the gold standard reconstruction technique; the results of this study suggest a low complication rate and high scores of satisfaction after reconstruction. However, the technique requires constant adaptation to obtain better satisfaction results.

New tomographic reconstruction technique based on Laplacian eigenfunction

This letter proposes a new tomographic reconstruction procedure based on the Laplacian eigenfunction (LEF) patterns, which are independent of the plasma cross-section and do not require the flux surface information. The process is benchmarked for the experimental data of Heliotron J plasma and the results are compared with the least-squares approximation by a Phillips–Tikhonov (PT)-type regularization, which is widely used as the standard technique for tomographic reconstruction. The reconstruction based on the LEF is found to be capable of determining the magnetic axis at different time locations efficiently in comparison with the PT-type regularization.