Mean Distance Research Articles

High-Resolution Magnetic Resonance Neurography at 7T: A Pilot Study of Hand Innervation.

The emergence of 7T clinical MRI technology has sparked our interest in its ability to discern the complex structures of the hand. Our primary objective was to assess the sensory and motor nerve structures of the hand, specifically nerves and Pacinian corpuscles, with the dual purpose of aiding diagnostic endeavors and supporting reconstructive surgical procedures. Ethical approval was obtained to carry out 7T MRI scans on a cohort of volunteers. Four volunteers assumed a prone position, with their hands (N = 8) positioned in a "superman" posture. To immobilize and maintain the hand in a strictly horizontal position, it was affixed to a plastic plate. Passive B0 shimming was implemented. Once high-resolution 3D images had been acquired using a multi-transmit head coil, advanced post-processing techniques were used to meticulously delineate the nerve fiber networks and mechanoreceptors. Across all participants, digital nerves were consistently located on the phalanges area, on average, between 2.5 and 3.5 mm beneath the skin, except within flexion folds where the nerve was approximately 1.8 mm from the surface. On the phalanges area, the mean distance from digital nerves to joints was approximately 1.5 mm. The nerves of the fingers were closer to the bone than to the surface of the skin. Furthermore, Pacinian corpuscles exhibited a notable clustering primarily within the metacarpal zone, situated on the palmar aspect. Our study yielded promising results, successfully reconstructing and meticulously describing the anatomy of nerve fibers spanning from the carpus to the digital nerve division, alongside the identification of Pacinian corpuscles, in four healthy volunteers (eight hands).

Exploring the effects of real-time online cardiac telerehabilitation using wearable devices compared to gym-based cardiac exercise in people with a recent myocardial infarction: a randomised controlled trial.

Exercise-based cardiac rehabilitation (CR) is a non-pharmacological multidisciplinary programme for individuals after myocardial infarction (MI) that offers multiple health benefits. One of the greatest barriers to CR participation is the travel distance to the rehabilitation centre. Remotely monitored CR appears to be at least as effective in improving cardiovascular risk factors and exercise capacity as traditional centre-based CR. Nevertheless, the efficacy of remotely monitored CR in individuals with a recent MI has yet to be examined. A total of 30 individuals (8 women, 22 men) after a recent (i.e., <4 weeks) MI were randomly allocated into two groups (online home-based and gym-based groups). Both groups underwent a 26-week CR programme three times per week. All patients performed baseline and 24-week follow-up measurements where peak oxygen uptake (VO2peak), mean daily steps, distance, and calories were assessed. The online group showed an improvement in mean daily steps (p < 0.05) and mean daily distance (p < 0.05) at 24 weeks compared to the gym-based group. The paired-sample t-test showed that all the assessed variables were statistically (p < 0.001) improved for both groups at 24 weeks. Pearson's r demonstrated positive correlations between VO2peak and mean daily distance (r = 0.375), and negative correlations between VO2peak and muscle (r = -0.523) and fat masses (r = -0.460). There were no exercise-induced adverse events during the study. Our findings might indicate that a real-time online supervised CR exercise programme using wearable technology to monitor the haemodynamic responses in post-MI patients is equally effective as a gym-based exercise programme.

Computed tomographic evaluation of the proximity of needles placed for perineural anesthesia of the palmar digital nerves to synovial structures in the foot: an ex vivo study.

Potential synovial penetration following palmar digital nerve blocks has not been investigated. To evaluate the proximity of needles placed for palmar digital nerve blocks to nearby synovial structures using computed tomography (CT). Descriptive observational study. In 18 cadaver forelimbs, sequential injection of the navicular bursa (NB), distal interphalangeal joint (DIPJ) and digital flexor tendon sheath (DFTS) was performed using 3, 5 and 10 mL diluted radiodense contrast medium, respectively. After each synovial injection, 25 gage needles were placed over the palmar digital nerves at the proximal aspect of the ungular cartilages (distal injections) and 1 cm further proximally (proximal injections), and CT examination was performed. Subsequently, needles were removed, and the synovial structures further distended with the same volume as for the first injection. Perineural needle placement and image acquisition were repeated. The distance between the needle tip and adjacent synovial structures was measured (mm) in reconstructed images. Results were analyzed in separate general linear mixed models, to determine the effect of needle position and synovial distension on the distance from the tip of the needle to the NB, DFTS and DIPJ. Synovial penetration was confirmed following 12/420 (3%) needle placements (NB n = 5, 1 after proximal and 4 after distal injections; DIPJ n = 2, DFTS n = 2, NB or DIPJ n = 3, all after distal injections). The mean distance from the needle tip to the NB and DIPJ was significantly smaller after the second distension (NB: p = 0.025; DIPJ: p < 0.001) and with the distal needle placements (NB: p < 0.001; DIPJ: p < 0.001). For the DFTS, the distance from the needle tip was significantly smaller with the proximal needle placements (p = 0.001). Ex-vivo study. There is a small risk of synovial penetration when performing palmar digital nerve blocks, especially when distension of adjacent synovial structures is present.

Muscular branches from the ulnar artery are the basis for a pedicled partial flexor digitorum superficialis muscle flap.

The feasibility of a pedicled flexor digitorum superficialis muscle flap was studied in 10 fresh cadavers. The number, length and distance from the flexion wrist crease of muscular branches from the ulnar artery in the distal 10 cm of the forearm were recorded. The mean number of muscular branches was 2.7 (range 1-4). The mean distance of the most distal branch was 35 mm (range 26-40) from the proximal wrist flexion crease. Its mean length was 20 mm (range 16-26). A partial muscle flap was raised on the most distal branch and transposed over the median nerve in the distal forearm. Dissection and transposition of this flap were feasible in all specimens. The reliable pattern of muscular branches to the flexor digitorum superficialis allows the elevation of a pedicled partial muscle flap that can cover the median nerve in the distal forearm.Level of evidence: V.

Identifying iliotibial band graft length and incision site may minimise the potential risk of harming adjacent structures: A novel approach for surgeon guidance.

The Iliotibial band (ITB) is a fibrous thickening of the fascia lata originating at the iliac crest and inserting at Gerdy's tubercle on the lateral tibia. The ITB significantly contributes to lateral knee stabilisation. Due to its size, tensile strength and easy access, it is widely used in orthopaedic surgery as an autograft during reconstruction procedures. Although ITB harvesting may result in complications, such as reduced knee extension or hip flexion, no safety margins or guidelines have been proposed for the procedure. Our aim was to determine the maximal safe length of an ITB graft, that is, that does not harm the lateral collateral ligament (LCL), tensor fasciae latae (TFL), gluteus maximus (GM) or adjacent structures, and reduce the complication rate. The study included 50 lower limbs of 25 human cadavers, previously fixed in 10% formalin solution. The inclusion criterion was the lack of visible signs of surgical interventions in the study region. Forty lower limbs were included in the study: 16 female (mean age 83.1 ± 3.4 years) and 24 male (mean age 84.2 ± 6.8 years). Dissection was performed with a previously established protocol. Morphometric measurements were then obtained twice by two researchers. The mean femur length was 404.8 mm [female (F) = 397.3 mm, male (M) = 409.9 mm, standard deviation (SD): F = 23.8 mm, M = 24.1 mm]. The mean ITB length was 318.9 mm (F = 309.4 mm, M = 325.2 mm, SD: F = 25.7 mm, M = 33.7 mm). Longer femurs were associated with longer ITB (p < 0.05). The mean distance from the insertion of the GM to the myofascial junction of TFL and ITB was 34.6 mm (F = 34.5 mm, M = 34.6 mm, SD: F = 3.2 mm, M = 3.3 mm). The longer femurs or ITBs demonstrated a greater distance from GM insertion to the myofascial junction of the TFL and ITB (p < 0.05). ITB grafts longer than 21 cm may contribute to the greater risk of TFL rupture. Based on simple measurements of the femur length, the surgeon may assess approximate ITB length, and thus assess the length of the maximal graft length. Moreover, to avoid harming the LCL, the incision should be performed 5 cm proximal to the articular surface of the lateral femoral condyle or 13 mm proximal to the lateral femoral epicondyle. Such preparation and preoperative planning may greatly reduce the risk of complications during ITB harvesting, while performing, for instance, the over-the-top technique for anterior cruciate ligament reconstruction in skeletally immature patients. Basic I.

The anatomy of the pelvic plexus in female cadavers: implications for retroperitoneal nerve-sparing surgery.

The inferior hypogastric plexus (IHP) is a crucial structure for female continence and sexual function. A nerve-sparing approach should be pursued to reduce the risk of pelvic plexus damage during retroperitoneal pelvic surgery. To analyse the relationship between the female IHP and several pelvic anatomical landmarks. Standardised cadaveric dissection was performed on 5 nulliparous female cadavers. The relationships of the IHP and the mid-cervical plane (MCP), the mid-sagittal plane (MSP), and the uterosacral ligament (USL) were investigated. Distance between IHP and MCP, MSP, and USL. Distances between the right IHP and the right MSP (mean distance: 16.3 mm; range: 10.0-22.5 mm) and the right USL (mean distance: 4.8 mm; range: 0-15.0 mm) were shorter than those between the left IHP and ipsilateral landmarks (left MSP distance: 23.5 mm; range 18.0-30.0 mm; left USL distance: 5.0 mm; range: 0-20.0 mm). Although the MCP was 3.3 mm (range: 2.5-4.0 mm) left and lateral to the midsagittal line, the right IHP was closer to the MCP (mean distance: 19.6 mm; range: 13.0-25.0 mm) than the left one (mean distance: 20.2 mm; range: 15.0-26.0 mm). Distances between the right IHP and the MSP, MCP, and ipsilateral USL, are shorter compared to these associated to the left IHP. Right autonomic pelvic plexus is closer to the midline planes and the ipsilateral USL. These anatomical relationships may be greatly helpful for pelvic surgeon while facing retroperitoneal pelvic surgery and looking for a nerve-sparing approach.

Anatomy of the Lateral Antebrachial Cutaneous Nerve: Landmarks for Procedures in the Cubital Fossa

The research outlines anatomical landmarks that may help surgeons in identifying the lateral antebrachial cutaneous nerve (LABCN) to minimize nerve damage during procedures in the cubital fossa. Twenty-eight fresh cadaveric upper extremities were dissected. The course of the LABCN was followed from the emerging point at the biceps brachii tendon (BT) to the mid-forearm. The nerve's relationships with the BT, lateral epicondyle (LE), antebrachial vein, and brachioradialis (BR) muscle were measured and documented. The LABCN emerged lateral to the BT in all specimens and crossed medially at the top of the BT in 50% of the cadavers. It was deep to the forearm superficial fascia in all cadavers. At the level of the LE, the nerve was located at a mean of 6.3 ± 3.1 mm medial to the BR. The LABCN aligns with the medial border of the BR at a mean of 68 mm distal to the interepicondylar line. The mean distance from the LE to the LABCN at the interepicondylar line was 24.5 ± 7.2 mm. The LABCN and antebrachial vein are in the same deep fascia plane, on average 47.6 ± 5 mm (37-55) from the LE. At the elbow joint level, 82.1% of the specimens have two branches for the LABCN, whereas 17.9% demonstrated only a single branch. Lateral antebrachial cutaneous nerve was situated approximately 6.8 cm distal to the interepicondyle line, positioned at the ulnar edge of the BR, and runs parallel with the antebrachial vein deep to the forearm fascia plane. The nerve crossed over the biceps tendon in 50% of the specimens. These findings suggest that the nerve should be identified 6-7 cm distal to the LE, followed by a proximal dissection. This study may help surgeons in identifying LABCN, and reducing the potential risk of LABCN injury.

Juxtacortical chondrosarcoma: An NCDB analysis of demographics and socioeconomic factors.

e23505 Background: Juxtacortical chondrosarcoma (JCC) is a rare cartilaginous tumor—accounting for less than 2% of all chondrosarcomas—and typically appears on the external surfaces of long bones. The prognosis of JCC is relatively promising compared to other chondrosarcomas, with the current therapy of choice being en-bloc resection. However, a significant amount of information regarding JCC remains unknown. Therefore, exploring diagnostic trends may provide greater insight into this cancer’s epidemiology and potential forms of treatment. The National Cancer Database (NCDB) was assessed to uncover the demographic factors in patients diagnosed with JCC. Methods: A retrospective cohort analysis utilizing the 2004–2020 National Cancer Database (NCDB) included 131 subjects with a histologically-confirmed diagnosis of JCC (ICD-0-3 code 9221). Demographic factors (age, sex, race, Hispanic status, insurance status, facility type, distance from facility, and Charleson-Deyo comorbidity score) were analyzed by descriptive statistics and incidence trends were interpreted in regression analysis. Results: Between 2004 and 2020, the NCDB reported a total of 131 patients with a confirmed diagnosis of JCC. This data indicated a rising incidence of patients diagnosed per year (R² = 0.0855), with an average age of diagnosis of 45 years (SD = 18, range = 8-88). Patients with JCC were more likely to be White (82%), of non-Hispanic origin (86%), and male (63%). The tumor was most commonly found in the long bones of the lower limbs (35%). Surgical removal was the primary treatment for the majority of patients (95%), while others received radiation (7%) or chemotherapy (4%). Most patients (83%) had a Charlson-Deyo comorbidity score of 0. Patients were commonly treated at academic and research facilities (61%), and no patients received palliative care. More than half of individuals were privately insured (57%) and resided in a metropolitan area with a population size of at least 1 million (59%). The mean distance between patient residence and treatment site was 104.1 miles (SD = 221, range = 11-1194 miles). Conclusions: To the best of our knowledge, this is the first study on juxtacortical chondrosarcoma utilizing NCDB data to address the significant lack of research on this subject. The majority of JCC patients are non-Hispanic, White, and have a primary site of diagnosis at the long bones of the lower limbs. This paper is the first to describe the socioeconomic factors of patients diagnosed with JCC: patients tend to be privately insured, live in large metropolitan areas, and are mostly treated in academic research facilities. Additional research is necessary to comprehend how socioeconomic and demographic factors influence the manner in which JCC patients are diagnosed and treated.

The efficacy and efficiency of percutaneous lidocaine injection for minimizing the carotid reflex in carotid artery stenting: A single-center retrospective study.

To assess whether local anesthetic infiltration could minimize the carotid baroreceptor reflex (CBR) which has an incidence after carotid artery stenting (CAS) that varies from 29% to 51%. This retrospective single-center study included 51 patients (mean age, 70.47 years) who underwent CAS for carotid stenosis. The groups included patients who underwent CAS for asymptomatic ischemic stroke (n=41) or symptomatic disease (n=10). Preprocedural percutaneous lidocaine injections (PPLIs) were administered to 70.6% and 5.9% of patients who underwent elective CAS and emergency CAS, respectively. Among patients who received PPLIs, the mean degree of stenosis was 80.5% (95% confidence interval [CI]: ±10.74, 51-98%). The mean distance from the common carotid artery bifurcation to the most stenotic lesion (CSD) was 8.3 mm (95% CI: ±0.97, 6.3-10.2 mm); the mean angle between the internal carotid artery and common carotid artery (CCA) trunk (IAG) was 65.6° (95% CI: ±2.39, 61-70°). Among patients who did not receive PPLIs, the mean degree of stenosis was 84.0% (95% CI: ±8.96, 70-99%). The mean CSD was 5.9 mm (95% CI: ±1.83, 1.9-9.9 mm); the mean IAG was 60.4° (95% CI: ±4.41, 51-70°). The procedure time was longer in the PPLI group than in the no PPLI group (28.19 [n=39] vs. 18.88 [n=12] days) (P=0.057); the length of intensive care unit stay was shorter in the PPLI group (20.01 [n=36] vs. 28.10 [n=5] days) (P=0.132). Targeted PPLI administration to the carotid bulb decreased aberrant heart rates and blood pressure changes induced by carotid stent deployment and balloon inflation. As CBR sensitivity increases with decreasing distance to the stenotic lesion from the CCA bifurcation, PPLIs may help stabilize patients during procedures for stenotic lesions closer to the CCA.

Factors associated with delay in breast biopsy in a vulnerable population.

e13526 Background: Prompt diagnosis and treatment of breast cancer can improve outcomes and reduce stress and anxiety in patients. Race, socioeconomic status, and education level are associated with delays in diagnosis in breast cancer patients. 63% of Louisiana’s parishes are classified as rural, and 18.8% of the population is below the poverty line (the second highest in the country). The above factors make access to care challenging. Our study aimed to identify factors associated with delay in breast biopsy after abnormal diagnostic imaging in our patient population. Methods: A retrospective cohort study including female patients &gt;18 years undergoing breast biopsy for abnormal diagnostic imaging findings from 1/1/2022 to 12/31/2022 at LSU Health, Shreveport, was done. Patients with a prior history of breast cancer, pregnant females, and patients with cognitive defects were excluded. Patients were followed from abnormal diagnostic imaging to biopsy. Descriptive analysis was done for baseline cohort characteristics. Univariate and multivariate logistic regression models were used to find 95% Confidence Interval and Odds ratio (ORs) for independent factors associated with time to biopsy (TTB). The study was approved by IRB. Results: 148 women (mean age [SD]: 54 [12] years) were included in the analysis. 67.5% were African American, and 25.6% lived in rural areas. The mean distance from the patient’s home to our center was 26.7 miles (Range: 3-219). The mean TTB from abnormal diagnostic imaging was 13.79 days (Range: 0-84), and 67.5% of patients had TTB of =&lt;14 days. A TTB of more than 14 days was considered a delay in biopsy. After adjusting for age, multivariate logistic regression showed rural residence was associated with TTB of &gt;14 days. (OR: 2.5, 95% CI: 1.15-5.67, p=0.02) (Table). A distance more than 40 miles from the hospital was associated with a higher likelihood of TTB of &gt;14 days on a multivariate model adjusted for age and race revealed (OR: 2.2, 95% CI: 1.004-5.10, p= 0.04). Conclusions: Patients residing in rural parishes and at a distance more than 40 miles from our center have a higher likelihood of delay in time to biopsy from the diagnostic imaging. Same-day breast biopsy should be prioritized in such patients to ensure timely diagnosis and treatment. Cancer Centers serving the safety net population can conduct similar studies and implement changes to ensure equitable access to care. [Table: see text]

Microsurgical and Descriptive Three-Dimensional Analysis of the Subarticular Trigone: A Guidemap for Standardizing Lateral Recess Decompression.

Background Lateral recess decompression has remained a cornerstone spinal procedure for decades. Despite its popularity, a significant lack of evidence in the literature exists concerning microsurgical anatomy and pertinent surgical landmarks, resulting in non-standardized nomenclature, descriptions, and surgical approaches. Objective This study provides an in-depth microsurgical and descriptive analysis of the subarticular trigone (SAT), serving as an anatomical guide and a tool to foster consistency in nomenclature and standardization of surgical approaches. Methods We analyzed 35 high-resolution lumbar spine CT scans, employing three-dimensional (3D) processing techniques. The SAT is introduced to delineate the bony prominence enveloping the superiomedial quadrant of the pedicle. The SAT encompasses two zones: (1) a superior zone above the superior pedicular line, corresponding to the medial part of the body of the ascending facet (AF), and (2) an inferior zone between the superior and middle pedicular lines, corresponding to the root of the AF and the medial pars/superior lamina. The superior subarticular point (SSP) and medial subarticular point (MESP) serve as key reference landmarks. The SAT forms the roof of the lateral recess and the region requiring resection during decompression of the traversing root in this anatomical corridor. Various measurements, including SSP and MESP to lateral pars, tip of the facet and spino-laminar junction distance, mean width of the sublaminar ridge (SLR), and percentage of the facet that requires resection for adequate SAT decompression, were carried out. Results The mean distance of the SSP to the lateral pars ranges from 7 to 9.2 mm, to the tip of the descending from 9.3 to 10.1 mm, and to the spino-laminar junction from 6.7 to 8.1 mm. The MESP is located at a mean distance of 5.4-6.9 mm from the medial pedicular line. The mean width of the SLR varies from 18.6 to 29.4 mm. Finally, the percentage of total facet width that needs to be removed to adequately decompress the SAT extends from 32% at L4 to 36% at L1. Conclusions This study presents comprehensive insights into the surgical, descriptive, and correlative anatomy of the lateral recess, emphasizing the SAT. The extrapolated data offer a framework for achieving uniformity in surgical planning and advocate for standardized nomenclature.

Validity of simple field tests as indicators of elite female field hockey match performance.

Due to the change in field hockey match format, the need exits for research to determine whether current fitness test are still valid indicators of match performance. This study aimed to determine the direct validity of the 5-m multistage shuttle test (5-m MST) and Yo-Yo Intermittent recovery level 1 test (Yo-Yo IR1) by correlating their results with external load measures in international field hockey matches. Nineteen female field hockey players completed the 5-m MST and Yo-Yo IR1 before nine matches. Players covered mean distances of 750.3 m±19.6 m (5-m MST) and 1649.7 m±277.6 m (Yo-Yo IR1). Average relative distance, relative player load, and high-intensity activity during matches were 107.8±16.3 m/min, 10.3±1.4 AU/min, and 10.0±3.0%, respectively. The 5-m MST showed small to moderate significant (P<0.05; r=0.21-0.5) correlations with relative distance and high-intensity activity, while the Yo-Yo IR1 only had a small negative significant (P<0.05; r=-0.27) correlation with high-intensity activity. Strong correlations (r>0.51) were found between the 5-m MST and Yo-Yo IR1. The tests demonstrated low direct validity for current field hockey matches due to weak relationships with relative load and running performance. Additionally, the strong correlation between the Yo-Yo IR1 and 5-m MST suggests that both tests may not be necessary to assess match readiness. Coaches should consider using better-validated fitness tests for this population and sport.

Extra-adrenal paraganglioma demographic data: A NCDB study.

e16293 Background: Extra-adrenal paragangliomas are rare neuroendocrine tumors that form near blood vessels and nerves outside of adrenal glands. Despite their rare occurrence, these tumors have higher rates of malignancy and varying survival rates compared to other paragangliomas. To better understand its epidemiology, there may be clinical value in analyzing the diagnostic trends of these tumors. This study utilized information provided by the National Cancer Database (NCDB) to examine the demographic factors of patient populations diagnosed with extra-adrenal paragangliomas. Methods: A retrospective cohort analysis using the 2004–2020 National Cancer Database (NCDB) included 133 patients with a histologically-confirmed diagnosis of extra-adrenal paraganglioma (ICD-O-3 code 8693). Demographic factors (age, sex, race, Hispanic status, educational attainment, insurance status, facility type, distance from facility, and Charles/Deyo score) were analyzed by descriptive statistics. Incidence trends were interpreted via regression analysis. Results: In the NCDB, 133 patients were identified with a confirmed diagnosis of extra-adrenal paraganglioma between 2004 and 2020. This database suggested a relatively stable number of patients diagnosed per year (R² = 0.022). Men (67%) were more likely to be diagnosed than women (35%), with an average age at diagnosis of 45.7 years (SD = 17.7, range = 11-83). Patients were most commonly non-Hispanic (88%), White (68%), and had a primary site of diagnosis in the retroperitoneum (35%). Treatment was primarily surgical resection (84%) followed by radiation (17%) and chemotherapy (8%). Most patients did not receive palliative care (98%). A majority of patients (77%) had a Charlson-Deyo comorbidity score of 0, with a 2 year survival rate of 92%, a 5 year survival rate of 79%, and a 10 year survival rate of 50%. Most patients were privately insured (65%) and received treatment in an academic research facility (56%). Many individuals lived in large metropolitan counties with a population larger than 1 million (56%), and resided a mean distance of 41.6 miles (SD = 74.4, range = 0.8 - 559.3) from the treatment facility. Conclusions: To the best of our knowledge, this is the first analysis of extra-adrenal paragangliomas utilizing the NCDB, and thus addresses a significant lack of knowledge on the subject. The majority of patients are non-Hispanic White men, with a primary site of diagnosis in the retroperitoneum. This is the first time that the socioeconomic factors of extra-adrenal paraganglioma patients have been described in the literature: patients tend to be privately insured, live in large metropolitan counties, and have 10 survival rate of 50%. Continued research is necessary to gain a deeper insight on the impact of socioeconomic and demographic factors that influence the diagnosis, treatment, and survivability of extra-adrenal paraganglioma patients.

Drilling the tibial tunnel in an arthroscopic popliteus bypass from the anteromedial tibial cortex decreases risk of popliteal vascular injury

PurposeDrilling the tibial tunnel in tibiofibular-based posterolateral corner (PLC) reconstructions is usually performed with a starting point from Gerdy's tubercle. Drilling the tunnel starting from the anteromedial tibial cortex could reduce the risk of popliteal neurovascular (PNV) injury. The purpose of this study is to assess the distance on Magnetic Resonance Imaging Scans (MRI) of the PNV bundle and peroneal nerve (PN) to these two different tunnel trajectories. MethodsA total of 87 MRI scans were assessed. The ideal exit point of the tibial tunnel in PLC reconstructions was marked. We added 10 mm from this point in a straight posterior and in an oblique trajectory, mimicking the two different tunnel trajectories and measured the distance to the PNV bundle and PN from these two points. ResultsThe mean distance of the tip of the guide wire drilled with a trajectory from Gerdy's tubercle to the PNV bundle and the peroneal nerve was respectively 13.2 mm (SD = 3.96) and 17.7 mm (SD = 4.39). The mean distance of the tip of the guide wire drilled with a trajectory from the anteromedial tibial cortex to the PNV bundle and the PN was respectively 19.6 mm (SD = 4.19) and 12.2 mm (SD = 3.96).). Drilling in a trajectory from the anteromedial tibial cortex significantly increases the distance to the PNV bundle (p < 0.001). ConclusionTibial tunnel drilling in a tibiofibular based PLC reconstruction from the anteromedial tibial cortex significantly increases the distance to the popliteal artery but with a decreased distance to the peroneal nerve. Level of evidencelevel IV.

“WATCH AND WAIT” STRATEGY IN RECTAL CANCER PATIENTS WITH A COMPLETE CLINICAL RESPONSE AFTER NEOADJUVANT CHEMORADIATION THERAPY: A SINGLE-CENTER EXPERIENCE

Background. The non-operative management of rectal adenocarcinoma (RA) after neoadjuvant chemoradiation therapy (nCRT) has gained increasing attention. The “Watch and Wait” (“W&amp;W”) strategy allows one to avoid surgery-related reduction in the quality of life due to permanent pelvic organ dysfunction or irreversible stoma. Still, the oncological safety of this strategy is under evaluation. Aim. To share a single-center experience of the “W&amp;W” strategy. Materials and Methods. The retrospective analysis of 125 patients who received nCRT in 2016—2021 was performed. Patients who met the European Society for Medical Oncology (ESMO, 2017) criteria of clinical complete response (cCR) and received non-operative management were analyzed. Results. Ten patients (8%) were re-staged after nCRT as cCR and followed the “W&amp;W” strategy. Patients’ characteristics: 7 female, 3 male; mean age 67.3 years. Tumor characteristics: pre-treatment N+ was present in 7 cases; G1 adenocarcinoma in a majority of cases; mean tumor distance from the anal verge — 5.85 cm; mean tumor circumference — 71%; mean tumor length — 3.87 cm. The mean follow-up time was 30 months. Local regrowth or/and distant metastases developed in 3 cases. The 2-year disease-free survival was 70%. Conclusions. Most of the patients following the “W&amp;W” strategy have benefited. However, to reduce the number of relapses, it is necessary to perform a more careful selection of patients.

Evaluation of multiple-vendor AI autocontouring solutions

BackgroundMultiple artificial intelligence (AI)-based autocontouring solutions have become available, each promising high accuracy and time savings compared with manual contouring. Before implementing AI-driven autocontouring into clinical practice, three commercially available CT-based solutions were evaluated.Materials and methodsThe following solutions were evaluated in this work: MIM-ProtégéAI+ (MIM), Radformation-AutoContour (RAD), and Siemens-DirectORGANS (SIE). Sixteen organs were identified that could be contoured by all solutions. For each organ, ten patients that had manually generated contours approved by the treating physician (AP) were identified, totaling forty-seven different patients. CT scans in the supine position were acquired using a Siemens-SOMATOMgo 64-slice helical scanner and used to generate autocontours. Physician scoring of contour accuracy was performed by at least three physicians using a five-point Likert scale. Dice similarity coefficient (DSC), Hausdorff distance (HD) and mean distance to agreement (MDA) were calculated comparing AI contours to “ground truth” AP contours.ResultsThe average physician score ranged from 1.00, indicating that all physicians reviewed the contour as clinically acceptable with no modifications necessary, to 3.70, indicating changes are required and that the time taken to modify the structures would likely take as long or longer than manually generating the contour. When averaged across all sixteen structures, the AP contours had a physician score of 2.02, MIM 2.07, RAD 1.96 and SIE 1.99. DSC ranged from 0.37 to 0.98, with 41/48 (85.4%) contours having an average DSC ≥ 0.7. Average HD ranged from 2.9 to 43.3 mm. Average MDA ranged from 0.6 to 26.1 mm.ConclusionsThe results of our comparison demonstrate that each vendor’s AI contouring solution exhibited capabilities similar to those of manual contouring. There were a small number of cases where unusual anatomy led to poor scores with one or more of the solutions. The consistency and comparable performance of all three vendors’ solutions suggest that radiation oncology centers can confidently choose any of the evaluated solutions based on individual preferences, resource availability, and compatibility with their existing clinical workflows. Although AI-based contouring may result in high-quality contours for the majority of patients, a minority of patients require manual contouring and more in-depth physician review.

Estimating differential penetration of green (532 nm) laser light over sea ice with NASA's Airborne Topographic Mapper: observations and models

Abstract. Differential penetration of green laser light into snow and ice has long been considered a possible cause of range and thus elevation bias in laser altimeters. Over snow, ice, and water, green photons can penetrate the surface and experience multiple scattering events in the subsurface volume before being scattered back to the surface and subsequently the instrument's detector, therefore biasing the range of the measurement. Newly formed sea ice adjacent to open-water leads provides an opportunity to identify differential penetration without the need for an absolute reference surface or dual-color lidar data. We use co-located, coincident high-resolution natural-color imagery and airborne lidar data to identify surface and ice types and evaluate elevation differences between those surfaces. The lidar data reveals that apparent elevations of thin ice and finger-rafted thin ice can be several tens of centimeters below the water surface of surrounding leads, but not over dry snow. These lower elevations coincide with broadening of the laser pulse, suggesting that subsurface volume scattering is causing the pulse broadening and elevation shift. To complement our analysis of pulse shapes and help interpret the physical mechanism behind the observed elevation biases, we match the waveform shapes with a model of scattering of light in snow and ice that predicts the shape of lidar waveforms reflecting from snow and ice surfaces based on the shape of the transmitted pulse, the surface roughness, and the optical scattering properties of the medium. We parameterize the scattering in our model based on the scattering length Lscat, the mean distance a photon travels between isotropic scattering events. The largest scattering lengths are found for thin ice that exhibits the largest negative elevation biases, where scattering lengths of several centimeters allow photons to build up considerable range biases over multiple scattering events, indicating that biased elevations exist in lower-level Airborne Topographic Mapper (ATM) data products. Preliminary analysis of ICESat-2 ATL10 data shows that a similar relationship between subsurface elevations (restored negative freeboard) and “pulse width” is present in ICESat-2 data over sea ice, suggesting that biased elevations caused by differential penetration likely also exist in lower-level ICESat-2 data products. The spatial correlation of observed differential penetration in ATM data with surface and ice type suggests that elevation biases could also have a seasonal component, increasing the challenge of applying a simple bias correction.

Effects of infant care posture and weight on static postural balance.

Studies investigating postural balance during various infant care postures have not been reported yet. The aim of this study was to measure static postural balance when holding an infant dummy in-arms and carrying an infant dummy on back according to different infant dummy weights. Sixteen healthy young subjects participated in a balance test. Infant dummies with weights of 4.6 kg (1-month) and 9.8 kg (12-month) were used in this study. All subjects were asked to naturally stand on a force platform in two infant care postures (holding an infant in-arms and carrying an infant on one's back). Center of pressure (COP) was measured from the force platform. Quantitative variables were derived from the COP. Two-way repeated measure analysis of variance (ANOVA) was performed to determine main effects of infant care postures, infant weight, and their interactions on COP variables. Back carrying a 12-month infant dummy had the greatest amplitude in all COP variables. Back carrying posture showed significantly greater mean distance and peak power, faster mean velocity, and wider COP area compared to holding posture (P< 0.05). There were significant weight effects of most COP variables mainly in AP direction (P< 0.01). Our results could contribute to the prevention of musculoskeletal diseases or prevention of fall due to various infant care activities by developing an assisting device to improve postural balance.

The Relationship between Trait-Based Functional Niche Hypervolume and Community Phylogenetic Structures of Typical Forests across Different Climatic Zones in China

Functional traits are pivotal for understanding the functional niche within plant communities. Yet, the relationship between the functional niches of typical forest plant communities across different climatic zones, as defined by functional traits, and their association with community and phylogenetic structures remains elusive. In this study, we examined 215 woody species, incorporating 11 functional traits spanning leaf economy, mechanical support, and reproductive phenology, gathered from forests in four climatic zones from tropical, subtropical, warm-temperate to cold-temperate zones in China and supplemented by the literature. We quantified the functional niche hypervolume (FNH), reflecting the multidimensional functional niche variability. We then probed into the correlation between the FNH and community and phylogenetic structures of forests. Our findings reveal that species richness significantly influences the geographic variance of functional niche space in forest vegetation across different climatic zones. Specifically, a community’s species richness correlates positively with the functional niche breadth occupied by the community species. The FNH of woody plants across diverse forest types shows significant associations with both the mean phylogenetic distance (MPD) and the mean nearest phylogenetic taxon distance (MNTD) of the communities. There is a progressive increase in tropical rainforest (TF), subtropical evergreen deciduous broad-leaved mixed forest (SF), and warm-temperate coniferous broad-leaved mixed forest (WF), followed by a decline in the cold-temperate coniferous forest (CF). This pattern suggests potential environmental filtering in CF, which may constrain the spatial extent of plant functional niches. Our research underscores the substantial variability in the FNH across China’s typical forest vegetation, highlighting the complex interplay between functional traits, community richness, and phylogenetic distance.

Morphological evaluation of the nasopalatine canal using cone beam computed tomography and its clinical implications for orthodontic miniscrew insertion.

The morphology of the nasopalatine canal is crucial in the planning of prosthetic restorations in the anterior region of the maxilla, as well as in the placement of orthodontic mini-implants. The aim of this study was to assess the morphology of the nasopalatine canal using cone beam computed tomography (CBCT) scans of patients from the University Dental Clinic in Krakow, Poland, to define the position of the canal in relation to common sites of palatal median microimplant placement, and to investigate potential correlations between the anatomy of the canal and age and gender of the patients. A total of 120 CBCT images were used to assess the anatomy of the nasopalatine canal in 3 planes of space. The bone thickness anterior to the nasopalatine canal and the distance between the distal margin of Stenson's foramen and the predicted midpalatal microimplant position were also measured. The most frequently observed canal type in the coronal plane was the Y-shaped canal, which was present in 60.8% of patients. The nasopalatine canal was classified as cone-shaped in 31.7% of the scans, cylindrical in 28.3%, hourglass-shaped in 27.5%, and banana-shaped in 12.5%. The mean length of the nasopalatine canal was 11.58 mm. The mean width of the canal was 2.89 mm at the nasal fossa level, 1.94 mm in the middle, and 5.09 mm at the palatal level. The mean bone thickness anterior to the nasopalatine canal was 9.07 mm at the level of the nasal opening, 6.84 mm at the level of the oral opening, and 7.32 mm in the middle. The mean distance between the distal margin of Stenson's foramen and the predicted midpalatal microimplant position varied from 0 to 11.94 mm, with a mean of 2.49 mm. Given the variety of nasopalatine canal forms and dimensions, detailed analysis of CBCT scans is essential prior to the placement of implants and microimplants.