Mean Cross-sectional Area Research Articles

Assessment of median nerve with magnetic resonance neurography in cases with carpal tunnel syndrome and controls

Background: Carpal tunnel syndrome (CTS) is a common peripheral nerve entrapment disorder that is diagnosed using clinical signs and symptoms and confirmed via nerve conduction studies (NCSs). While NCS is a semi-invasive procedure, magnetic resonance imaging (MRI) is a non-invasive diagnostic tool that detects macroscopic nerve abnormalities and evaluates a patient's surgical or medication treatment options. This study assessed magnetic resonance neurography (MRN)’s diagnostic and grading value by comparing it to electrodiagnostic studies in patients with CTS and healthy individuals. Methods: This was a cross-sectional study on 27 wrists with CTS and 27 healthy wrists. After history taking and physical examination, we employed an NCS to confirm and determine the severity of CTS, then MRN and diffusion tensor imaging (DTI) were used to calculate apparent diffusion coefficient (ADC), fractional anisotropy (FA), and cross-sectional area (CSA). Results: 18 patients with CTS (27 median nerves) and 15 healthy controls (27 median nerves) were evaluated. The mean FA in the CTS group was significantly lower (0.38 ± 0.05 vs. 0.45 ± 0.06, P < 0.001).The mean CSA and ADC were higher in patients with CTS but not statistically significant. FA’s diagnostic cut-off was 0.42, with a sensitivity of 70.4% and a specificity of 63%. Conclusion: MRN with DTI can be an effective and non-invasive diagnostic technique for the detection of CTS. The FA measure demonstrated adequate sensitivity and specificity for differentiating patients with CTS from healthy individuals.

Digital image analysis of vertebral body L4 and its ossification center in the human fetus.

Using a Siemens-Biograph 128 mCT camera the morphometric analysis of the L4 vertebral body and its ossification center were done in 55human fetuses aged 17 to 30weeks. No sex differences were found. The mean height, transverse and sagittal diameters of L4 vertebral body followed the logarithmic functions: y = -11.797+ 5.208 × ln(age) ± 0.372, y = -23.462 + 9.428 × ln(age) ± 0.702, y = 2.770 + 13.521 × ln(age) ± 1.722, respectively. The mean cross-sectional area of L4 vertebral body followed the linear function: y = -30.683 + 1.976 × age ± 2.701. The mean volume of L4 vertebral body followed the second-degree polynomial function: y = -93.983+ 0.385 × (age)² ± 23.707. The mean transverse and sagittal diameters of the ossification center of L4 vertebral body followed the natural logarithmic function: y = -27.106 + 10.178 × ln(age) ± 0.769 and y = -13.345 + 5.458 × ln(age) ± 0.424, respectively. The mean cross-sectional area and the volume of the ossification center of L4 vertebral body followed the linear function: y = -30.683 + 1.976 × age ± 2.701 and y = -43.214 + 2.760 × age ± 4.085, respectively.

A simplified approach to define cervical vertebral levels in spinal cord MRI studies.

Spinal cord (SC) cross-sectional areas (CSAs) assessed with MRI have proven to be extremely valuable imaging markers in several diseases. Among the challenges is the delineation of vertebral levels to determine level-dependent changes in cord atrophy. With this study, we aimed to (1) test the hypothesis that there is proportionality in the position of the first six intervertebral discs and the length of the upper portion of the SC and (2) show that a proportionality approach can simplify the CSA assessment across vertebrae offering good reliability. Forty-six volunteers underwent standard T2-weighted and T1-weighted cervical SC MRI acquisitions. The distance between the obex and the intervertebral discs (from C2-C3 to T1-T2) was measured on the T2-weighted acquisitions of the entire cohort. In a test-retest experiment on 12 subjects, the % disc position values were used to define vertebral levels, and a comparison was performed with manual vertebrae assignment in terms of mean CSA and its coefficient of variation. The mean upper cord length for the cohort was 144.0±13.1mm. The discs' level % position in the upper cord was found to be fairly consistent, with standard deviations of 0.8%-1.7%. The mean vertebral CSA obtained with the proportionality method was substantially equivalent to the manual approach in terms of mean CSA values and test-retest reliability. With this study, we propose a proportionality method for the assignment of cervical SC vertebral levels that can simplify the processing of MRI datasets in the context of CSA measurements.

Study of Carpal Tunnel Syndrome Using Electroneurography and Ultrasound in a Spanish Cohort

Introduction: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy. Its diagnosis is clinically supported by the electroneurography (ENG). The use of ultrasound (US) has increased in recent years. Our objectives are: to describe the ENG and US findings in patients with suspected CTS, based on age, sex and anthropometric data; and to study the correlation of both tests based on the severity of CTS. Material and methods: prospective study of patients with suspected CTS who undergo ENG and US. ENG examination: antidromic sensory median at 3rd and 4th finger; distal motor of median. US: crosssectional area (CSA) prior to or within the tunnel (higher values). Inclusion criteria: patients aged 18 to 85 years. Exclusion criteria: previous trauma or previous surgery for CTS or forearm, carpus or hand. Statistical study with the SPSS 29.0 program. Results: 400 nerves from 266 patients (52.59 ± 12.09 years) were studied, 183 women and 83 men. According to the ENG, 129 did not have CTS, 61 were incipient, 113 mild, 19 moderate and 75 severe. The mean CSA was 8.37 ± 1.21 mm2 in non-CTS, 10.09 ± 1.45 mm2 in early, 11.33 ± 1.87 mm2 in mild, 14.63 ± 1.92 mm2 in moderate and 15.46 ± 3.33 mm2 in severe CTS, with a significance of p<0.01 (95% CI) in the ANOVA test. The highest and inverse correlation appears between the conduction velocities (CV) at the 4th finger with CSA (-0.816) and CV at the 3rd finger with CSA (-0.800), which coincides with the most sensitive ENG values for the diagnosis of CTS. Discussion: CSA is an appropriate test as a complement to ENG in the diagnosis of CTS. However, it has limitations when establishing the cut-off point between normality and neuropathy, as well as when classifying based on severity

3D-CT measurements of Airway Morphology in Severe CFM Patients: A comparative study between ascending ramus distraction osteogenesis and Bone Grafting

This study investigated the differential effects of mandibular distraction osteogenesis (MDO) and bone grafting on upper airway morphology in pediatric patients with Pruzansky-Kaban type IIB and III craniofacial microsomia (CFM). A retrospective analysis was performed on medical records and three-dimensional computed tomography (3D-CT) scans of CFM patients who had undergone MDO or bone grafting as primary interventions. Preoperative and postoperative imaging data were evaluated to quantify and compare changes in airway dimensions between the two surgical groups. Parameters such as airway volume, surface area, length, mean and minimum cross-sectional areas, and sphericity were measured across the nasopharynx, oropharynx, and laryngopharynx. Data normality was assessed using the Shapiro-Wilk test, and statistical comparisons were made using either paired t-tests or the Wilcoxon signed-rank test, depending on distribution characteristics. Eighteen children with type IIB and III CFM were included in the study, with 11 undergoing MDO and 7 receiving bone grafting. In the MDO group, postoperative measurements revealed significant increases in nasopharyngeal length and surface area (P=0.001, P=0.036), along with notable improvements in oropharyngeal length, volume, surface area, mean and minimum cross-sectional areas, and sphericity (P<0.05). In contrast, the bone grafting group exhibited a significant increase only in nasopharyngeal length (P=0.019), without substantial postoperative changes in other airway parameters. These findings suggested that MDO leads to more pronounced improvements in upper airway morphology, particularly in the nasopharynx and oropharynx, compared to bone grafting, which demonstrated minimal impact on airway dimensions.

Revision surgery for recurrent ulnar nerve compression following failed subcutaneous transposition.

Recurrent ulnar nerve compression after primary anterior subcutaneous transposition is relatively rare, and revision surgery is challenging. This study retrospectively evaluated the clinical outcomes of revision anterior subcutaneous transposition for recurrent ulnar nerve compression. Eight patients who underwent revision anterior subcutaneous transposition for recurrent ulnar nerve compression were enrolled in this study. The outcomes were based on preoperative and postoperative symptoms, physical examination findings, and electromyographic evaluation. Ulnar nerve enlargement was preoperatively found in all patients with a mean cross sectional area of 0.15 cm2 (range, 0.14-0.18 cm2). Intraoperative findings showed that recurrent compression occurred in three areas, including the medial intermuscular septum (n = 5), the medial epicondyle (n = 6) and nerve entrance to forearm fascia (n = 1). Post-operation, significant improvements were observed in ring/little finger numbness (from severe to mild, p = 0.031), grip strength (from 48.00% to 80.38% of the intact side, p < 0.001) and McGowan grade (from Grade III to Grade I, p = 0.049). Postoperative electromyography test also showed significant improvement in motor nerve conduction at elbow (velocity, 23.30 ± 9.598 vs. 35.30 ± 9.367, p = 0.012; amplitude, 3.40 ± 3.703 vs. 5.65 ± 2.056, p = 0.007) and sensory nerve conduction at wrist (velocity, 27.04 ± 22.450 vs. 36.45 ± 18.099, p = 0.139; amplitude, 1.44 ± 1.600 vs. 4.00 ± 2.642, p = 0.011). Seven of the eight patients reported satisfaction with the postoperative results. Revision anterior subcutaneous transposition was an effective treatment for recurrent ulnar nerve compression from prior failed procedures.

Feasibility of a cross-face reconstruction of the mental nerve—A cadaveric simulation study with histomorphometric analysis

IntroductionThe inevitable sacrifice of the inferior alveolar nerve (IAN) during oncologic resections results in substantial sensory impairment, impacting crucial functions such as speech, saliva retention, and mastication. This study investigates the feasibility of sensory restoration through cross-face reconstruction of the mental nerve via a contralateral mental nerve branch. MethodsThe cross-face reconstruction procedure was simulated in five formalin-fixed cadavers for both sides to evaluate the anatomic fundamentals and the nerve gap between the mental nerve main trunk and the transferred contralateral mental nerve branch. Furthermore, a histomorphometric analysis was performed to assess cross-sectional area and axon counts. ResultsThe mean gap distance between the main mental nerve trunk and the transferred contralateral branch was 15.3mm. End-to-end coaptation was achieved in 9 out of 10 simulations. The mean cross-sectional area was 0.996 mm2 at the main mental nerve trunk and 0.253mm2 at the coaptation site of the nerve branch. The mean donor-to-recipient axon ratio was found to be 0.3:1. ConclusionThe cadaveric simulation demonstrates the feasibility of a cross-face reconstruction of the mental nerve with only minimal gapping. Advantages of the proposed technique include the use of shorter nerve grafts, minimizing donor site morbidity and enabling fast reinnervation. This technique may offer a promising method for enhancing the quality of life for a patient group with increasing survival rates and life expectancy.

Effects of Short-Term Treatment of Rabbit Extraocular Muscle With Ciliary Neurotrophic Factor.

Little is known about the effect of ciliary neurotrophic factor (CNTF) on extraocular muscles, but microarray studies suggested CNTF might play a role in the development and/or maintenance of strabismus. The effect of short-term treatment of adult rabbit extraocular muscle with injected CNTF was examined for its ability to alter muscle characteristics. Eight adult New Zealand white rabbits received an injection into one superior rectus muscle of 2 µg/100 µL CNTF on 3 consecutive days. One week after the first injection, the rabbits were euthanized, and the treated and contralateral superior rectus muscles were assessed for force generation capacity and contraction characteristics using an in vitro stimulation protocol and compared to naïve control superior rectus muscles. All muscles were analyzed to determine mean cross-sectional areas and expression of slow twitch myosin heavy chain isoform. Short-term treatment of rabbit superior rectus muscles with CNTF resulted in a significant decrease in muscle force generation, but only at the higher stimulation frequencies. Significantly decreased myofiber cross-sectional areas of the treated muscles correlated with the decreased generated force. In addition, there were significant changes to contractile properties of the treated muscles, as well as a decrease in the number of myofibers expressing slow twitch myosin heavy chain. We show that short-term treatment of a single rabbit superior rectus muscle results in decreased myofiber size, decreased force, and altered contractile characteristics. Further studies are needed to determine if it can play a role in improving alignment in animal models of strabismus.

A comparison of handheld versus cart-based ultrasound in the evaluation and diagnosis of carpal tunnel syndrome

BackgroundCarpal tunnel syndrome (CTS) is responsible for over 90 % of median nerve neuropathies. Though a clinical diagnosis, evaluation of nerve conduction via electrodiagnostic studies (EDX) and median nerve cross sectional area (CSA) through sonographic imaging provides supporting evidence and insight into disease severity. The advent of handheld ultrasound devices offers a portable, cost-effective and non-invasive method for median nerve assessment, yet its accuracy compared to traditional cart-based ultrasound has not been assessed in this setting. Methods43 consecutive patients who presented to an outpatient orthopedic clinic within a large academic institution for symptoms consistent with CTS between August 2023 and April 2024 were included. Handheld sonography was performed with the Clarius Convex L20 HD3 8–20 MHz transducer. The GE Venue Go with a 4–20 MHz linear transducer was used for conventional cart-based ultrasound evaluation. A paired t-test was performed to compare the mean cross-sectional area (CSA) measured with the GE machine to the mean CSA measured with the Clarius transducer (p < 0.05). ResultsThe average CSA measurement obtained with the GE was 14.21 ± 4.89 mm2. The average CSA measurement obtained with the Clarius handheld transducer was 13.54 ± 4.50 mm2. The mean difference between the GE and Clarius groups was 0.62 mm2 (95 % CI = −1.47 to 2.71), p = 0.55. ConclusionCSA measurements of the median nerve obtained by a handheld ultrasound transducer are comparable to those measured by a traditional cart-based ultrasound machine for carpal tunnel diagnosis. The adoption of handheld ultrasounds in clinical settings holds the potential for quicker, more precise diagnoses and broader access to imaging.

Hydrogen sulfide inhibits skeletal muscle ageing by up-regulating autophagy through promoting deubiquitination of adenosine 5'-monophosphate (AMP)-activated protein kinase α1 via ubiquitin specific peptidase 5.

Hydrogen sulfide (H2S), the third gasotransmitter discovered, regulates a variety of physiological functions. Whether H2S alleviates skeletal muscle ageing by regulating autophagy has not been reported. Mice were administered 150mg/kg/day of D-galactose (D-gal), and C2C12 myotubes were cultured in 20g/L D-gal to induce ageing. Sodium hydrosulfide (NaHS) was employed as an exogenous donor in the treatment group. The intracellular concentration of H2S was quantified by the 7-azido-4-methylcoumarin fluorescence probe. The proteins involved in the ubiquitin-mediated degradation of AMPKα1 were detected by liquid chromatography tandem mass spectrometry (LC-MS/MS) and co-immunoprecipitation (Co-IP). S-sulfhydration of USP5 was tested by a biotin-switch assay. Associated proteins were analysed by western blot. NaHS was found to effectively restore the H2S content in both ageing gastrocnemius (+91.89%, P<0.001) and C2C12 myotubes (+27.55%, P<0.001). In comparison to theD-gal group, NaHS was observed to increase the mean cross-sectional area of muscle fibres (+44.91%, P<0.001), to decrease the collagen volume fraction of gastrocnemius (-81.32%, P=0.001) and to reduce the β-galactosidase-positive area of C2C12 myotubes (-28.74%, P<0.001). NaHS was also found to reverse the expression of muscle atrophy F box protein (MAFbx), muscle-specific RING finger protein 1 (MuRF1), Cyclin D1 and p21 in the ageing gastrocnemius tissue (MAFbx: -31.73%, P=0.008; MuRF1: -32.37%, P=0.003; Cyclin D1: +45.34%, P=0.010; p21: -25.53%, P=0.022) and C2C12 myotubes (MAFbx: -16.38%, P<0.001; MuRF1: -16.45%, P=0.003; Cyclin D1: +40.23%, P<0.001; p21: -35.85%, P=0.026). The AMPKα1-ULK1 pathway was activated and autophagy was up-regulated in NaHS-treated gastrocnemius tissue (p-AMPKα1: +61.61%, P=0.018; AMPKα1: +30.64%, P=0.010; p-ULK1/ULK1: +85.87%, P=0.005; p62: -29.07%, P<0.001; Beclin1: +24.75%, P=0.007; light chain 3 II/I [LC3 II/I]: +55.78%, P=0.004) and C2C12 myotubes (p-AMPKα1: +77.49%, P=0.018; AMPKα1: +26.18%, P=0.022; p-ULK1/ULK1: +38.34%, P=0.012; p62: -9.02%, P=0.014; Beclin1: +13.36%, P<0.001; LC3 II/I: +79.38%, P=0.017; autophagy flux: +24.88%, P=0.034) compared with the D-gal group. The effects of NaHS on autophagy were comparable to those of acadesine and LYN-1604, and chloroquine could reverse its effects on ageing. LC-MS/MS and Co-IP experiments demonstrated that USP5 is a deubiquitinating enzyme of AMPKα1. Following the knockdown of USP5, the activation of AMPKα1 was decreased (p-AMPKα1: -42.10%, P<0.001; AMPKα1: -43.93%, P<0.001), autophagy was inhibited (p-ULK1/ULK1: -27.51, P=0.001; p62: +36.00, P<0.001; Beclin1: -22.15%, P<0.001) and NaHS lost its ability to up-regulate autophagy. NaHS was observed to restore the expression (gastrocnemius: +62.17%, P<0.001; C2C12 myotubes: +37.51%, P=0.003) and S-sulfhydration (+53.07%, P=0.009) of USP5 and reduce the ubiquitination of AMPKα1. H2S promotes the deubiquitination of AMPKα1 by increasing the expression and S-sulfhydration of USP5, thereby up-regulating autophagy and alleviating skeletal muscle ageing.

Predictor of left main coronary artery size: an intravascular ultrasound study in Southeast Asia population.

Left main (LM) percutaneous coronary intervention (PCI) has expanded rapidly in the past decade, with up to fourfold increase annually. Recent trials found that intravascular imaging (IVI)-guided LM PCI resulted in lower risks of cardiac death and stent failure due to suboptimal PCI compared to angiography-guided PCI. IVI usage has increased in recent years; however, its utilization remains variable across regions and is still incredibly low in developing countries. Furthermore, to date, there is no data about LM size in the Southeast Asian population. This study aims to determine the mean external elastic membrane (EEM) diameter, cross-sectional area (CSA) of LM, and its predictor. This is a cross-sectional observational study on 100 patients with coronary artery disease (CAD) who underwent IVUS-guided PCI with a pullback to LM in Dr. Hasan Sadikin General Hospital Bandung, Indonesia, from January 2020 until December 2022. Linear regression was used to determine the predictors of LM size. There were 100 segments of LM. LM's mean EEM diameter and CSA were 5.02 ± 0.43mm and 19.93 ± 3.48mm2. Body surface area (BSA) is an independent predictor of EEM diameter and CSA with a positive linear relationship (p 0.001 and p 0.0001). Hypertension is an independent predictor of EEM diameter with a positive linear relationship (p 0.034). The linear equation to predict EEM diameter and CSA were (2.741 + 1.272BSA(m2) + 0.165 hypertension (yes)) and (2.745 + 9.601BSA(m2)), respectively. The LM coronary artery size of the Southeast Asian population was comparable with the previous studies. BSA and hypertension are independent predictors of EEM diameter, with BSA being stronger than hypertension. Neither sex nor other cardiovascular risk factors affect the LM size. The knowledge of coronary artery size will help the clinician have a reference for intervention, especially when no intravascular imaging is available.

Diagnostic accuracy and confounders of vagus nerve ultrasound in amyotrophic lateral sclerosis—a single-center case series and pooled individual patient data meta-analysis

BackgroundSeveral single-center studies proposed utility of vagus nerve (VN) ultrasound for detecting disease severity, autonomic dysfunction, and bulbar phenotype in amyotrophic lateral sclerosis (ALS). However, the resulting body of literature shows opposing results, leaving considerable uncertainty on the clinical benefits of VN ultrasound in ALS.MethodsRelevant studies were identified up to 04/2024 and individual patient data (IPD) obtained from the respective authors were pooled with a so far unpublished cohort (from Munich). An IPD meta-analysis of 109 patients with probable or definite ALS (El Escorial criteria) and available VN cross-sectional area (CSA) was performed, with age, sex, ALS Functional Rating Scale-revised (ALSFRS-R), disease duration, and bulbar phenotype as independent variables.ResultsMean age was 65 years (± 12) and 47% of patients (± 12) had bulbar ALS. Mean ALSFRS-R was 38 (± 7), and mean duration was 18 months (± 18). VN atrophy was highly prevalent [left: 67% (± 5), mean CSA 1.6mm2 (± 0.6); right: 78% (± 21), mean CSA 1.8 mm2 (± 0.7)]. VN CSA correlated with disease duration (mean slope: left − 0.01; right − 0.01), but not with ALSFRS-R (mean slope: left 0.004; mean slope: right − 0.002). Test accuracy for phenotyping bulbar vs. non-bulbar ALS was poor (summary receiver operating characteristic area under the curve: left 0.496; right 0.572).ConclusionVN atrophy in ALS is highly prevalent and correlates with disease duration, but not with ALSFRS-R. VN CSA is insufficient to differentiate bulbar from non-bulbar ALS phenotypes. Further studies are warranted to analyze the link between VN atrophy, autonomic impairment, and survival in ALS.

Diagnostic accuracy of ultrasound and MR imaging in peroneal neuropathy: A prospective, single-center study.

Magnetic resonance imaging (MRI) findings in peroneal neuropathy are not well documented and the prognostic value of imaging remains uncertain. Upper limits of cross-sectional area (CSA) on ultrasound (US) have been established, but uncertainty regarding generalizability remains. We aimed to describe MRI findings of the peroneal nerve in patients and healthy controls and to compare these results to US findings and clinical characteristics. We prospectively included patients with foot drop and electrodiagnostically confirmed peroneal neuropathy, and performed clinical follow-up, US and MRI of both peroneal nerves. We compared MRI findings to healthy controls. Two radiologists evaluated MRI features in an exploratory analysis after images were anonymized and randomized. Twenty-two patients and 38 healthy controls were included. Whereas significant increased MRI CSA values were documented in patients (mean CSA 20 mm2 vs. 13 mm2 in healthy controls), intra- and interobserver variability was substantial (variability of, respectively, 7 and 9 mm2 around the mean in 95% of repeated measurements). A pathological T2 hyperintense signal of the nerve was found in 52.6% of patients (50% interobserver agreement). Increased CSA measurements (MRI/US), pathological T2 hyperintensity of the nerve and muscle edema were not predictive for recovery. Imaging is recommended in all patients with peroneal neuropathy to exclude compressive intrinsic and extrinsic masses but we do not advise routine MRI for diagnosis or prediction of outcome in patients with peroneal neuropathy due to high observer variability. Further studies should aim at reducing MRI observer variability potentially by semi-automation.

Ex vivo diffusion tensor imaging of the plantar nerves is feasible in the horse.

The objective of this study was to optimize an MRI-based diffusion tensor imaging (DTI) protocol for imaging the plantar nerves at the level of the tarsus in normal equine limbs. 12 pelvic cadaver limbs from horses without evidence of proximal suspensory pathology were imaged with a 3T MRI system. For diffusion-weighted imaging, b values of 600, 800, and 1,000 s/mm2 were tested. Data were processed with DSI Studio. Cross-sectional areas of the medial and lateral plantar nerve along the plantar tarsus were recorded. The length and number of fiber tracts, signal-to-noise ratio, and DTI variables were recorded. At the level of interest, the mean cross-sectional areas of the plantar nerves ranged from 5.03 to 7.42 mm2. The DTI maps consistently generated tracts in the region of the lateral and medial plantar nerves with DTI values in the range of values reported for peripheral nerves in humans. Our findings demonstrate that DTI of the medial and lateral plantar nerves can be performed successfully and used to generate quantitative parameters including fractional anisotropy and mean, axial, and radial diffusivity. Quantitative data generated with this imaging technique can be used to noninvasively characterize the microstructural integrity of neural tissue with possible applications in the evaluation of pathologic changes to the plantar tarsal and metatarsal nerves of horses with proximal suspensory desmopathy.

Determination of muscle shape deformations of the tibialis anterior during dynamic contractions using 3D ultrasound.

In this paper, we introduce a novel method for determining 3D deformations of the human tibialis anterior (TA) muscle during dynamic movements using 3D ultrasound. An existing automated 3D ultrasound system is used for data acquisition, which consists of three moveable axes, along which the probe can move. While the subjects perform continuous plantar- and dorsiflexion movements in two different controlled velocities, the ultrasound probe sweeps cyclically from the ankle to the knee along the anterior shin. The ankle joint angle can be determined using reflective motion capture markers. Since we considered the movement direction of the foot, i.e., active or passive TA, four conditions occur: slow active, slow passive, fast active, fast passive. By employing an algorithm which defines ankle joint angle intervals, i.e., intervals of range of motion (ROM), 3D images of the volumes during movement can be reconstructed. We found constant muscle volumes between different muscle lengths, i.e., ROM intervals. The results show an increase in mean cross-sectional area (CSA) for TA muscle shortening. Furthermore, a shift in maximum CSA towards the proximal side of the muscle could be observed for muscle shortening. We found significantly different maximum CSA values between the fast active and all other conditions, which might be caused by higher muscle activation due to the faster velocity. In summary, we present a method for determining muscle volume deformation during dynamic contraction using ultrasound, which will enable future empirical studies and 3D computational models of skeletal muscles.

The median nerve´s system of connective tissue distal to the pronator teres to the carpal tunnel

BackgroundConnective tissue serves a role beyond mere spatial filling. Furthermore, there is increasing evidence that connective tissue plays an important role in the pathogenesis of conditions such as carpal tunnel syndrome (CTS). According to our hypothesis, the median nerve (MN) is surrounded by a system of connective tissue distal to the pronator teres and extending up to, and including, the carpal tunnel. MethodsTo visualize the connective tissue surrounding the median nerve, we dissected the forearms of 15 body donors from pronator teres to the carpal tunnel, created plastination slices stained with Periodic Acid-Schiff (PAS), and injected ink into the seen spaces. We verified our findings with a segmentational analysis of radiological data of 10 healthy individuals. ResultsWe macroscopically describe the median nerve´s system of connective tissue (MC) distal to the pronator teres and up to and including the carpal tunnel. This system creates, connects, and separates spaces. At least from the pronator teres to the carpal tunnel it also creates subspaces from proximal to distal. For the MC, we established a mean cross-sectional area of 153.1 mm2 (SD=37.15) in the carpal tunnel. The median nerve consistently resides at the center of this MC, which further connects to flexor muscles of the forearm, and to the radius bone. In the carpal tunnel, the MC creates subspaces inside. There, it also acts as the outermost internal layer enveloping flexor tendons, and the MN. DiscussionThe term MC does not negate but orders the existence of other “connectives”, like subsynovial connective tissue, endo-, epi- or perineuria, epimysia, periostea, or peritendinea, to a hierarchy related to the median nerve. Diseases of the MN are common. Knowing the anatomy of the MC and how it relates to MN function may help clinicians recognize and understand conditions like CTS.

Safety and effectiveness of the sutureless integrated stented graft prosthesis in an animal model

BackgroundProlonged circulatory arrest time is an independent risk factor for postoperative adverse events of type A aortic dissection (TAAD) surgery. Further reduction of the circulatory arrest time is essential to improve surgical outcomes. This study aimed to evaluate the safety and effectiveness of the novel Sutureless Integrated Stented (SIS) graft prosthesis in an animal experiment. Materials and methodsStraight type of the SIS graft prosthesis was implanted into the descending aorta of 10 adult male sheep, and the use of the device was scored on a scale of 1–10. Aortic digital subtraction angiography (DSA) was performed at 4, 14, and 26 weeks to investigate the prostheses. After 26 weeks, the animals were sacrificed for histological analysis. ResultsThe immediate success rate of the surgery was 100 %, and the overall mean score of the use of the device was 9.65 ± 0.99. Three animals died from non-device-related causes during follow-up. Aortic DSA showed filling defects in 5 animals. Histological analysis revealed that all prostheses were intact. Except for 2 early deaths, the other 8 prostheses were endothelialized with mild inflammation, foreign body reactions, and intimal fibrosis. The mean cross-sectional area of the sutureless region was reduced by 26.4 % (range, 1.3–39.1 %). ConclusionsThe safety and effectiveness of the novel SIS graft prosthesis were acceptable, and the delivery system exhibited a promising performance. Using the SIS graft prosthesis in TAAD surgery was expected to simplify the procedures and shorten the circulatory arrest time. Further large-scale clinical trials are required to verify these findings.

Micro-CT Imaging of Tracheal Development in Down Syndrome and Non-Down Syndrome Fetuses.

Down syndrome (DS) is associated with airway abnormalities including a narrowed trachea. It is uncertain whether this narrowed trachea in DS is a consequence of deviant fetal development or an acquired disorder following endotracheal intubation after birth. This study aimed to compare the tracheal morphology in DS and non-DS fetuses using microfocus computed tomography (micro-CT). Twenty fetal samples were obtained from the Dutch Fetal Biobank and divided into groups based on gestational age. Micro-CT images were processed to analyze tracheal length, volume, and cross-sectional area (CSA). Mean tracheal length and tracheal volume were similar in DS and non-DS fetuses for all gestational age groups. Mean, minimum, and maximal tracheal CSA were statistically significantly increased in the single DS fetus in the group of 21-24 weeks of gestation, but not in other gestational age groups. In 90% of all studied fetuses, the minimum tracheal CSA was located in the middle third of the trachea. Tracheal development in DS fetuses was similar to non-DS fetuses between 13 and 21 weeks of gestation. This suggests that the narrowed tracheal diameter in DS children may occur later in fetal development or results from postnatal intubation trauma. The narrowest part of the trachea is in majority of DS and non-DS fetuses the middle third. 3 Laryngoscope, 134:4389-4395, 2024.

Cut-off value for a normal posterior tibial nerve to diagnose tarsal tunnel syndrome amongst people of different race in Pretoria, South Africa.

Posterior tibial nerve (PTN) cross-sectional area (CSA) reference values for the diagnosis of tarsal tunnel syndrome (TTS) using ultrasound imaging exist in several countries but not in South Africa (SA). Therefore, the objective was to measure the CSA reference values for PTN in SA. Ultrasound CSA measurements of PTN in both ankles on 112 participants were performed, the mean measurement was recorded, and the effect of race, age, gender, and body mass index (BMI) were recorded. In this study, the primary variables age and BMI affect the CSA measurement of the PTN. A positive correlation was found between PTN asymptomatic size and age (r = 0.196, P < 0.05), size and BMI (r = 0.200, P < 0.05). Age (categories) had a mean value of 3.17 for the age group 36-45 years (95% confidence interval (CI) 2.9-3.4). The mean BMI was 30.0 kg/m2 (CI 28.57-31.08). As for the asymptomatic PTN, a mean CSA reference value of 0.10 cm2 was obtained. With increase in age and BMI, a greater PTN measurement will occur. Race appears to be a contributing factor, but further research is needed in this regard. The reference CSA value for normal PTN should be set at 0.10 cm2 for all racial groups for a basic musculoskeletal ultrasound exam protocol in South Africa.

Wallerian Degeneration Assessed by Multi-Modal Magnetic Resonance Imaging of Cervical Spinal Cord Is Associated With Neurological Impairment After Spinal Cord Injury.

While Wallerian degeneration (WD) is a crucial pathological process induced with spinal cord injury (SCI), its underlying mechanisms is still understudied. In this study, we aim to assess structural alterations and clinical significance of WD in the cervical cord following SCI using multi-modal magnetic resonance imaging (MRI), which combines T2*-weighted imaging and diffusion tensor imaging (DTI). T2*-weighted images allow segmentation of anatomical structures and the detection of WD on macrostructural level. DTI, on the other hand, can identify the reduction in neuroaxonal integrity by measuring the diffusion of water molecules on the microstructural level. In this prospective study, 35 SCI patients (19 paraplegic and 16 tetraplegic patients) and 12 healthy controls were recruited between July 2020 and May 2022. The hyperintensity voxels in the dorsal column was manually labeled as WD on T2*-weighted images. The mean cross-sectional area (CSA) and mean DTI indexes of WD at the C2 level were calculated and compared between groups. Correlation analysis was used to determine the associations of the magnitude of WD with lesion characteristics and clinical outcomes. Compared with controls, SCI patients showed evident hyperintensity (35/35) and decreased neuroaxonal integrity (p < 0.05) within the dorsal column at the C2 level. A higher neurological level of injury was associated with a larger mean CSA and reduction in neuroaxonal integrity within WD (p < 0.05). Smaller total and dorsal tissue bridges were related to greater mean CSA and lower fractional anisotropy values in WD (p < 0.05), respectively. Moreover, SCI participants with significantly larger CSAs and significantly lower microstructural integrity had worse sensory outcomes (p < 0.05). This comprehensive evaluation of WD can help us better understand the mechanisms of WD, monitor progression, and assess the effectiveness of therapeutic interventions after SCI.