Posterior Position Research Articles

Autopsy-Based Cross-Sectional Observational Study On Carotid Artery Injury In Non-Penetrative Neck Trauma

Background: Non-penetrative neck trauma poses a significant risk of carotid artery injury, which can lead to severe consequences. Diagnosis of carotid artery injury in non-penetrative trauma remains challenging due to delayed clinical presentation. Research on non-penetrative mechanisms of injury is relatively less common compared to penetrating trauma. This study aims to analyse patterns of vascular injuries in compression injuries to the neck, focusing on non-penetrative trauma. Materials and Methods: A cross-sectional study was conducted in a Forensic Medicine Department of Government Stanley medical college, Chennai, over a one-year period, analysing 150 cases of non-penetrative neck trauma. Post-mortem data, including gross and histopathological findings, were collected and analysed. Results & Discussion: Among the 150 cases studied, hanging was the most prevalent cause of blunt cervical trauma. The majority of cases affected individuals were between the age group 21 and 40 years, with male preponderance. Gross examination revealed intimal tears in a proportion of cases, with histopathological examination identifying a higher prevalence of injuries. Posterior knot ligatures were predominant in both complete and partial hanging cases, correlating with a higher incidence of carotid body hemorrhage. The association between posterior knot position and carotid body hemorrhage emphasizes specific vulnerabilities in hanging cases. Conclusion: The findings of the study emphasize the importance of forensic investigations in identifying vascular injuries, guiding injury prevention strategies, and informing medicolegal proceedings. Further research is needed to enhance diagnostic and management approaches in clinical and forensic practice.

Maternal and neonatal outcomes of occiput posterior vaginal delivery.

The occiput posterior (OP) position is the most common fetal malposition associated with poorer maternal outcomes compared to the occiput anterior (OA) position. However, there are no equivalent reports for women in Japan. This study aimed to investigate the maternal and neonatal outcomes of OP delivery in Japan. This retrospective study was conducted at a tertiary hospital in Japan. Singleton pregnant women who delivered vaginally at and after 37 weeks of gestation between January 2000 and May 2023 were included. Participants were divided into OA and OP groups and pregnancy outcomes were compared. Multivariable analysis was performed to adjust for background. In total, 13 852 eligible participants were divided into OA (13 633, 98.4%) and OP (218, 1.6%) groups. Maternal weights were significantly higher in the OP group than in the OA group, but there were no significant differences in maternal age, height, BMI, and parity. The incidence of assisted vaginal delivery (6.0% vs. 25.2%, adjusted odds ratios [aOR] 6.97), third- or fourth-degree perineal laceration (0.9% vs. 2.8%, aOR 3.52), postpartum hemorrhage (4.3% vs. 8.7%, aOR 2.17), and prolonged second stage of labor (11.3% vs. 29.4%, aOR 4.75) were significantly higher in the OP group. On the other hand, there were no significant differences in neonatal outcomes. The present study showed that OP vaginal deliveries require more time, and the increased number of assisted vaginal deliveries resulted in more maternal lacerations and hemorrhage. Maternal complications should be noted in the management of OP deliveries.

Long-term Outcomes of a Modified Straight-line Palate Repair Technique: Low Speech Correcting Surgery and Fistula Rates.

The goal of cleft palate (CP) repair is to restore normal speech, however, rates of velopharyngeal insufficiency (VPI) after palatoplasty remain high. We present a modified straight-line palate repair (SLR) technique that facilitates velum length to alleviate VPI. The technique releases nasal mucosa with the levator muscle off the hard palate. This study assesses speech outcomes of this modified SLR technique. Secondary aims are to assess fistula outcomes. A retrospective review evaluated non-syndromic patients with Veau III or IV CP ± cleft lip who underwent SLR from 1993-2023. Patients undergoing modified SLR were compared to those receiving traditional SLR. Outcomes included postoperative palatal fistula, fistula location, fistula repair rates, and velopharyngeal insufficiency (VPI) correcting surgery rates. Multivariable logistic regression was performed. Overall, 343 patients were included (160 modified SLR, 183 traditional SLR). Average length of follow-up from palatoplasty was 6.4±5.3 years. Modified SLR was associated with fewer fistulas than traditional SLR (3.1% vs 15.3%, Odds Ratio [OR]: 0.19; p=0.001), lower fistula repair rates (0.6% vs 13.1%, OR: 0.26; p=0.022), and lower secondary speech surgery rates (0.8% vs 16.0%, OR: 0.046; p=0.003). The modified SLR technique resulted in lower rates of VPI surgery, as well as fewer fistulas and lower rates of fistula repairs compared to traditional SLR at six years postoperatively. We hypothesize that releasing the nasal mucosa off the hard palate facilitates more posterior positioning of the levator muscle and less restricted medial mobilization of the oral mucosa, which lengthens the velum to alleviate VPI.

Fetal rotation examined with ultrasound in a sub-Saharan population: A longitudinal cohort study.

Occiput posterior (OP) position rates at birth are 5%-8% in studies mainly comprising white European women. The anthropoid pelvis is common in black African women. This pelvic shape has a narrow anterior segment and an ample room posteriorly. The fetal head is wider posteriorly, and the OP position may be favorable in women with an anthropoid pelvic shape. We aimed to examine the fetal rotation with ultrasound longitudinally during the active phase of labor in a sub-Saharan population. We also aimed to examine associations between fetal position, delivery mode, and duration of labor. The study was conducted at Kilimanjaro Christian Medical Centre in Moshi, Tanzania from the 19th of November 2023 to 13th of April 2024. Women with a single fetus in cephalic presentation, gestational age >37 weeks, without previous or pre-labor cesarean section were eligible. Fetal position was classified as occiput anterior (OA) from 10 to 2 o'clock, occiput transverse (OT) at 3 or 9 o'clock, and OP position from 4 to 8 o'clock. The study participants comprised 215 women. Fetal positions at admission, in the first and second stage of labor and at birth are presented in the graphical figure. In all, 65/215 (30.2%) fetuses were in OP position at admission, 59/204 (28.9%) in the first stage, 38/210 (18.1%) in the second stage and 35/215 (16.3%) were delivered in OP position. The OP rates at birth were 25/92 (27.2%) in nulliparous and 10/123 (8.1%) in parous women. The operative delivery rate was 10/157 (6.4%) in women with ultrasound assessed fetal position as OA in the second stage (six cesarean section and four vacuum extractions), and 28/48 (58.3%) in the non-OA group (27 cesarean section and one vacuum extraction) (p < 0.01). The hazard ratio for delivery in the second stage was 0.26 (95% CI 0.13-0.52) for the non-OA versus the OA group in nulliparous women and 0.25 (95% CI 0.12-0.52) in parous women. The persistent OP position rate at birth was higher than previously reported, and the operative intervention rate was nine time higher in women with the fetus in non-OA versus OA position in the second stage.

Osteochondritis Dissecans of the Capitellum: Influence of Activity on Lesion Location Within a Zone of Propensity.

There may be an association between repetitive stress on the elbow and capitellar osteochondritis dissecans (COCD). The influence of activity on the characteristics or specific location of the lesion within a capitellar zone of propensity remains unclear. The purpose of this study was to evaluate COCD in gymnasts and baseball players compared with a non-upper extremity (non-UE) sport COCD cohort. It was hypothesized that activity would influence presentation and lesion location and characteristics. Cross-sectional study, Level of evidence, 3. Consecutive patients presenting with COCD treated in a tertiary sports medicine practice between March 2006 and March 2021 were reviewed. Demographic and imaging lesion characteristics were recorded. The sagittal inclination angle position of the lesion center relative to the humeral shaft was recorded. Intra- and interrater reliability was confirmed (intraclass correlation coefficient, 0.808; intraclass correlation coefficient, 0.824, respectively). Participants were analyzed by activity. A total of 126 elbows were identified: 68 in gymnasts, 31 in baseball players, and 27 in patients with no history of UE sports. The mean age of the participants was 12.5 years (range, 8-18 years). All (100%) unilateral cases of osteochondritis dissecans (OCD) in baseball players occurred in the dominant throwing arm, compared with less hand-dominance correlation in gymnasts (64%) and non-UE athletes (67%). Significantly, 14 of the 20 (70%) patients with bilateral OCD were gymnasts (P = .036). In non-UE athletes, lesions occurred at a mean sagittal inclination angle of 52.7° (±13.8°), with a mean lateral containment of 4.7 (±2.1) mm. In gymnasts, lesions occurred more posteriorly at 41.2° (±14.9°), with a lateral containment of 3.6 (±1.9) mm. In baseball players, COCDs occurred at 55.1° (±11.9°), with a lateral containment of 2.5 (±1.6) mm. These more posterior lesion positions in gymnasts (P = .001) and lesser lesion containment noted in gymnasts (P = .015) and baseball players (P < .001) were significant. Compared with COCD lesions in adolescents with no history of UE sports, gymnastics participation (impact weightbearing) correlated with a higher rate of bilateral lesion formation and a more posterior (extended) lesion position. Baseball participation (resulting in valgus shear forces in the elbow) resulted in a sagittal position similar to non-UE lesions, but more lateral and with less containment.

Adductor tubercle appears more posterior on radiographs of knees with trochlear dysplasia

PurposeThe purpose of this study was to compare the radiographic positions of commonly utilized landmarks between symptomatic and normal knees and to assess the influence of morphologic risk factors. Methods3D models were created from knees of patients with patellar instability and compared to control knees. On the 3D models, the adductor tubercle, medial epicondyle and gastrocnemius tubercle were marked. A 2D view was created from these models to simulate radiographs, and the radiographic location of each landmark was described with respect to the anteroposterior relation to the posterior cortical line, and proximal-distal relationship to the posterior condylar line. The position of each landmark was compared between symptomatic and control groups and assessed for variations in position with severity of anatomic risk factors. Results40 patients were included in this study. On the 2D views, the medial epicondyle was found to be more posterior and more distal than in the control group. Association between severity of trochlear dysplasia and posterior position of the adductor tubercle trended toward significance (R=0.43, R2=0.18, p=0.058). In symptomatic knees with trochlear dysplasia, the radiographic landmark for the medial epicondyle was posterior by 3.3mm (p=0.052), adductor tubercle by 2.7mm (p=0.009), and gastrocnemius tubercle by 3.9mm (p=0.010) when compared to symptomatic knees without dysplasia. ConclusionThis study demonstrates that commonly utilized anatomic landmarks are more posterior and distal on radiographs in knees with patellar instability when compared to normal knees. Trochlear dysplasia is associated with the radiographic landmarks of the adductor and gastrocnemius tubercles appearing 3mm posterior to those without dysplasia, and its severity is associated with posterior radiographic appearance of the adductor tubercle. Level of EvidenceIII, Retrospective Case Control

MENTOPLASTIA DE AVANÇO PARA CORREÇÃO DE RETRUSÃO MANDIBULAR – RELATO DE CASO.

The article addresses advancement mentoplasty as an effective solution for the correction of mandibular retrusion, a condition characterized by abnormal posterior positioning of the mandible, which has significant aesthetic and functional consequences. In this sense, the objective of this study was to construct a clinical case report, which describes the entire process of planning and performing the surgery in a 24-year-old patient who presented aesthetic complaints due to mandibular retrusion. The methodology used was case report and literature review, using articles published in the last 10 years to corroborate or refute the clinical findings. The surgical intervention involved an intraoral incision, chin osteotomy and fixation with a “Chin” plate with 6mm Advancement – System 2.0 (TRAUMEC).® The postoperative results indicated a significant improvement in facial harmony, in addition to an increase in the patient’s self-esteem. The study discusses the relevance of a detailed preoperative evaluation, emphasizing the importance of personalized surgical planning to ensure the effectiveness of the results. The reviewed literature corroborates the findings of the study, highlighting that advancement mentoplasty not only corrects mandibular retrusion but also improves patients’ quality of life by restoring facial aesthetics. The research contributes to the discussion on orthognathic surgery, reinforcing advancement mentoplasty as a safe and effective technique for the correction of mandibular anomalies, by combining functional and aesthetic aspects in its surgical approach. In addition, the use of three-dimensional technology in planning reinforces the precision and personalization of the treatment, ensuring long-lasting and aesthetically satisfactory results.

The value of intrapartum ultrasound in predicting mode of delivery: A prospective cohort study

Abstract Objectives: Ultrasound contributes significantly to management of labor, delivery and prevention of adverse maternal and fetal outcomes. Among many suggested intra-partum ultrasound parameters, the use of transperineal ultrasound scan to assess the angle of progression (AoP) and levator hiatus anteroposterior diameter (APD) has been suggested to result in a more objective evaluation of labor progress. The aim of this study was to assess this claim. Methods: This was a prospective observational cohort study involving primparous term singleton vertex presentation pregnant patients &gt;18 years old admitted in the first stage of labor between January 2021 and May 2023. All patients provided an informed written consent. This investigation utilized both transabdominal and transperineal ultrasonography for comprehensive fetal and pelvic floor assessment. Transabdominal ultrasound evaluated standard parameters including fetal occiput position, biometry number, viability, presentation, and estimated fetal weight. Intrapartum transperineal ultrasonography, specifically performed during the first stage of labor, focused on the Levator Hiatus, measuring its anteroposterior diameter (APD) at rest and during Valsalva maneuver, as well as the angle of progression (AOP). Results: The study population comprised 609 participants with a mean age of 22.8 ± 4.3 years and a high prevalence of being overweight and obesity (38.8% and 57.8%, respectively). When comparing patients who had an intrapartum CS to those who had a normal vaginal delivery (NVD). However, on logistic regression, age, BMI, gestational age, posterior occiput presentation, head circumference (HC), AOP (V) and APD (V) as significant predictors for both ICS and 2nd stage CS (p&lt;0.05). Conclusion: This study demonstrated that maternal age, BMI, gestational age, occiput posterior position, Angle of progression at Valsalva and levator hiatus anteroposterior diameter at Valsalva were independent significant predictors for Intrapartum cesarean section in primiparous women at term When the ratio between HC/APD at rest, BPD/APD at Valsalva and HC/APD at Valsalva is high, while the APD at Valsalva, AoP Valsalva values are low, cesarean section was more likely to be the mode of delivery. Keywords: Intrapartum ultrasound, angle of progression, anteroposterior diameter of levator hiatus, mode of delivery, intrapartum cesarean section.

Effective prism diopter for strabismus measurement: Conversion from anterior Prentice position to posterior parallel position and from glass prism to acrylic prism.

In clinical ophthalmology, prisms, commonly made of glass, are labeled based on the prism diopter (PD) value measured in the anterior Prentice position. However, they are often used in the posterior parallel position for practicality, causing a discrepancy between labeled and effective PD. This study proposes a conversion tool to address this issue. Geometric optical analysis was employed to calculate the effective PD of glass prisms in the posterior parallel position. A lookup table was created to convert the labeled PD of the anterior Prentice position to the effective PD when the prism is used in the posterior parallel position. Clinical data from 162 patients with horizontal strabismus were collected to validate the method. Glass prism measurements, converted to effective PD, were compared with acrylic prism results. The variations were significant in glass prism PD with rotation in the anterior Prentice position but stability in the posterior parallel position. Clinical deviations were larger with glass prisms, especially exceeding 30 PD, compared with acrylic prisms. Converted PD from glass prisms correlated well with acrylic prisms (R2 = 0.94, P = 0.002). The half-width of the 95% limit of agreement was ±12.32 PD. The proposed conversion table is valid, facilitating consistency between clinical and literature-based prism use in different positions and materials.

Appropriate sagittal positioning of femoral components in total knee arthroplasty to prevent fracture and loosening.

This study aimed to investigate the optimal sagittal positioning of the uncemented femoral component in total knee arthroplasty to minimize the risk of aseptic loosening and periprosthetic fracture. Ten different sagittal placements of the femoral component, ranging from -5 mm (causing anterior notch) to +4 mm (causing anterior gap), were analyzed using finite element analysis. Both gait and squat loading conditions were simulated, and Von Mises stress and interface micromotion were evaluated to assess fracture and loosening risk. During gait, varied sagittal positioning did not lead to excessive Von Mises stress or micromotion. However, under squat conditions, posterior positioning (-4 and -5 mm) resulted in stress exceeding 150 MPa at the femoral notch, indicating potential fracture risk. Conversely, +1 mm and 0 mm sagittal positions demonstrated minimal interface micromotion. Slightly anterior sagittal positioning (+1 mm) or neutral positioning (0 mm) effectively reduced stress concentration at the femoral notch and minimized interface micromotion. Thus, these positions are deemed suitable to decrease the risk of aseptic loosening and periprosthetic femoral fracture.

Measurement and analysis of condylar morphology and thickness of the roof of the glenoid fossa in patients with unilateral second molar scissor bite

Objective The objective of this study was to measure and analyze the joint space, condylar morphology, and thickness of the roof of the glenoid fossa (RGF) in patients with unilateral second molar scissor bite using cone beam CT (CBCT). Methods A total of 80 patients were included in this study. Forty patients with a normal posterior occlusal relationship, who attended the Department of Orthodontics at the First Hospital of Shanxi Medical University from December 2021 to August 2023, were selected as the control group. The experimental group consisted of 40 patients with unilateral second molar scissor bite during the same period. All patients underwent CBCT scanning, and the resulting images were analyzed using the NNT viewer software in multiplanar reconstruction (MPR). Axial, coronal, and sagittal adjustments were made for each patient. Results In the control group, the right and left joint spaces (PS, SS, AS), the height of the upper part of the condyle, and the depth of the glenoid fossa did not show statistically significant differences (P > 0.05). When comparing bilateral condylar morphology and joint space in the experimental group, it was found that the posterior joint space on the scissor bite side was greater than that on the normal occlusion side, while the anterior joint space on the scissor bite side was smaller than that on the normal occlusal side. Additionally, the height of the upper condyle and the depth of the glenoid fossa on the scissor bite side were greater than that on the normal occlusal side, with statistically significant differences (P < 0.05). However, there were no statistically significant differences in SS, internal and external joint diameter, as well as anterior and posterior diameters (P > 0.05). The comparison of the minimum thickness of the roof of the glenoid fossa in both the sagittal and coronal directions between the patients in the experimental group and the control group showed no statistically significant difference (P > 0.05). Furthermore, the asymmetry index of the supracondylar height in the control group was significantly smaller than that in the experimental group, displaying a statistically significant difference (P < 0.05). The differences in the asymmetry indices of the anterior and posterior diameters of the condyle, as well as the inner and outer diameters, were not statistically significant (P > 0.05). When analyzing the position of the condyle in the sagittal direction of the glenoid fossa in the patients of the control group, it was observed that the majority were in the anterior and medial positions, with only 10% and 5% being in the posterior position. However, the analysis of the condyle position in the sagittal direction of the glenoid fossa in the experimental group revealed statistically significant differences (P < 0.05), with the condyle position on the scissor bite side being more anterior. Conclusion Unilateral second molar scissor bite can result in anterior displacement of the condyle, greater height of the condyle superiorly as well as the depth of the glenoid fossa.

Intrapartum Ultrasound Guidance to Make Safer Any Obstetric Intervention: Fetal Head Rotation, Assisted Vaginal Birth, Breech Delivery of the Second Twin.

Intrapartum ultrasound (US) is more reliable than clinical assessment in determining parameters of crucial importance to optimize the management of labor including the position and station of the presenting part. Evidence from the literature supports the role of intrapartum US in predicting the outcome of labor in women diagnosed with slow progress during the first and second stage of labor, and randomized data have demonstrated that transabdominal US is far more accurate than digital examination in assessing fetal position before performing an instrumental delivery. Intrapartum US has also been shown to outperform the clinical skills in predicting the outcome and improving the technique of instrumental vaginal delivery. On this basis, some guidelines recommend intrapartum US to ascertain occiput position before performing an instrumental delivery. Manual rotation of occiput posterior position (MROP) and assisted breech delivery of the second twin are other obstetric interventions that can be performed during the second stage of labor with the support of intrapartum US. In this review article we summarize the existing evidence on the role of intrapartum US in assisting different types of obstetric intervention with the aim to improve their safety.

Rebozo and advanced maternal postures: A promising set of intrapartum interventions to reduce persistent occiput posterior position of the fetal head.

Spinning Babies® procedures and the Rebozo technique have been recently implemented as additional interventions in laboring women with a fetus in occiput posterior position (OPP) to favor the rotation to an anterior position, which improve birth experience and health outcomes. Our study aimed to compare the probability of occurrence of persistent OPP (POPP) of the fetal head at the second stage of labor between retrospective and prospective cohorts and to assess associated sociodemographic, obstetric and intrapartum factors. We conducted a combined prospective and retrospective cohort study including 1500 women giving birth in 2017 (retrospective cohort) and 779 between 15 May and 15 December 2023 (prospective cohort). Each cohort was divided into two sub-cohorts depending on presence of OPP. Primary outcomes were compared the probability of occurrence of POPP in the two OPP sub-cohorts by a log binomial regression and logistic regression. A p<0.05 was considered statistically significant. Data analysis was performed using Stata/MP18.0. The proportion of OPP at the onset of labor was similar between the two cohorts (34.9% vs 35.1%). The probability of occurrence of POPP was significantly lower in the prospective OPP sub-cohort (27.7%, n=65/235) compared to the retrospective OPP sub-cohort (35.8%, n=154/430) (risk difference, RD= -0.081; 95% CI: -0.15 - -0.008; p=0.031). In the retrospective OPP sub-cohort, maternal age ≥35 years (RD=0.096; 95% CI: 0.001-0.190, p=0.044) and nulliparity (RD= -0.100; 95% CI: -0.190 - -0.001, p=0.036) were significantly associated with the probability of POPP. Our findings suggest a potential benefit of a set of interventions combining Spinning Babies® and the Rebozo technique in decreasing the probability of POPP.

Evaluating Surgical Accuracy in Bimaxillary Surgery: A Systematic Review and Meta-Analysis of Mandible-First versus Maxilla-First Approaches.

Mandible-first surgery (MdFS) has gained attention as an alternative to the traditional maxilla-first surgery (MxFS) in bimaxillary procedures. Given the distinct sequence of operations between these approaches, evaluating the clinical advantages of MdFS compared to MxFS is crucial for optimizing surgical decision-making. This systematic review and meta-analysis examine intraoperative achievability and postoperative stability between these two surgical approaches. A thorough literature search was performed using PubMed, Embase, Web of Science, and MEDLINE, covering articles published from 2013 to 2023. Studies included were retrospective, prospective, and randomized trials that compared the accuracy and/or stability of MdFS with MxFS. The primary endpoint for the meta-analysis was the standardized mean difference in surgical accuracy for translational movements, with a secondary focus on rotational accuracy. A total of 11 studies encompassing 712 patients met the inclusion criteria. The analysis suggested that MdFS might reduce accuracy in the sagittal dimension (CI, 0.05 to 0.74) but offered greater achievability in the vertical direction (CI, - 0.47 to - 0.07). Additionally, MdFS was associated with a relatively posterior (CI, - 1.18 to - 0.60) and inferior (CI, - 0.64 to - 0.07) positioning of the maxillomandibular complex. Despite certain limitations, our findings indicate that MdFS can achieve clinical outcomes similar to MxFS in terms of both accuracy and stability. However, further researches with larger sample sizes and more rigorous study designs are necessary to validate these conclusions. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of contents or the online Instructions to Authors www.springer.com/00266 .

Ring only repair of bileaflet mitral valve prolapse with mitral regurgitation: Insights from computational modeling

This study evaluates the efficacy of annuloplasty repair as a standalone procedure for treating bileaflet mitral valve prolapse with mitral regurgitation (MR). Various flexible ring bands for MR of different severities were compared to assess their biomechanical impact and treatment outcomes. Computational beating heart models, based on the Living Heart Human Model, were utilized to simulate annuloplasty repairs. Repairs using bands of varying lengths were modeled on moderate and severe MR cases, considering bileaflet mitral valve prolapse. Key parameters, including regurgitant orifice area (ROA), prolapse severity, coaptation length, leaflet position, and deformation, were computed to compare conditions before and after implantation. Annuloplasty repairs effectively reduced the ROA in both moderate and severe MR cases, achieving complete sealing in selective instances. Additionally, annuloplasty repair corrected bileaflet prolapse, with prolapse severity decreasing as the annular size increased. Successful coaptation was indicated by the expansion of each leaflet’s contact area distribution and percentage in contact with the opposing leaflet. The risk of systolic anterior motion, that may obstruct the left ventricular outflow tract, was minimized, as the anterior leaflet was directed towards the posterior position. In conclusion, annuloplasty repair alone can effectively treat MR when an appropriate band length is selected. It facilitates a significant reduction in ROA, correction of bileaflet prolapse, and improvement in leaflet coaptation. These findings have important clinical implications, potentially offering a less complex surgical treatment avenue and reducing complications in the management of MR.

Synthesized V7 QRS Amplitude and Oversensing Episodes in Patients With Subcutaneous Implantable Cardioverter-Defibrillators.

Patients with subcutaneous implantable cardioverter-defibrillators (S-ICDs) experience an oversensing episode (OS) more frequently than those with transvenous ICDs. However, no established electrocardiography (ECG) parameters can accurately detect an OS. This study aimed to evaluate the incidence of an OS in real-world clinical practice and the association of synthesized 18-lead ECG (syn18-ECG) parameters with an OS. We retrospectively included 21 consecutive patients who underwent S-ICD implantation and collected syn18-ECG parameters. We placed the generator in a deep posterior position and defined an OS as an inappropriate charging episode caused by cardiac or noncardiac signals. A SMART pass filter and two tachyarrhythmia zones were programed. The most frequent underlying heart disease was Brugada/J wave syndrome (n = 7). During a median follow-up period of 1188 days, an OS was observed in six patients (28.6%). The QRS amplitude in synthesized V7 lead (synV7) was significantly lower in the OS group than in the non-OS group (0.59±0.17 vs. 0.91±0.35mV, p=0.019). The optimal cutoff value of synV7 QRS amplitude was 0.61mV, with a sensitivity of 80.0% and a specificity of 83.7% for predicting an OS. Univariate logistic analysis showed that a synV7 QRS amplitude of <0.61mV was only associated with an OS (odd ratio, 20.0; 95% confidence interval, 1.66-241.72; p=0.018). In patients with S-ICDs, an OS was not a rare complication during long-term follow-up. A low synV7 QRS amplitude was associated with a high OS incidence.

It is challenging to reproduce both anatomical and functional aspects of anterolateral reconstruction: postoperative 3D-CT analysis of the femoral tunnel position

BackgroundThis study aimed to evaluate the femoral tunnel position and fiber length of the anterolateral ligament (ALL) reconstruction compared with the natural anatomy of the ALL. We also evaluated whether the femoral tunnel position would affect residual pivot shift.MethodsThis study was a retrospective review of 55 knees that underwent ALL reconstruction considering the anatomical and functional aspects, during primary anterior cruciate ligament (ACL) reconstruction in the presence of a high-grade pivot shift or revisional ACL reconstruction. We determined the position of the femoral tunnel and the length of graft using a three-dimensional (3D)-computed tomography (CT) model after ALL reconstruction. We also measured graft excursion during surgery and examined pivot shift 2 years after surgery. We conducted a subgroup analysis of femoral tunnel position, fiber length, isometricity, and residual pivot shift depending on whether the tunnel was anterior or posterior to the lateral epicondyle (LE). We also performed a subgroup analysis depending on whether the ACL reconstruction was primary or revisional.ResultsThe mean femoral tunnel position was 2.04 mm posterior and 14.5 mm proximal from the center of the LE. The mean lengths of the anterior and posterior fibers were 66.6 and 63.4 mm, respectively. The femoral tunnel was positioned more proximally than the anatomical position, and both anterior and posterior ALL fibers were longer than the natural anatomy. The anteroposterior femoral tunnel position was significantly correlated with anterior (p = 0.045) and posterior (p = 0.037) fiber excursion. In the subgroup analysis, there was no significant difference in the residual pivot shift between the posterior and anterior tunnel positions. However, there were significant differences for proximal position (p < 0.001) and fiber length (p = 0.006). There was no significant difference between primary and revisional ACL regarding femoral tunnel position and fiber lengths.ConclusionIt is challenging to reproduce both anatomical and functional aspects of ALL reconstruction in both primary and revision ACL reconstruction. Especially for functional reconstruction, the femoral tunnel tended to be positioned more proximally than the anatomical position. However, the femoral tunnel position did not affect functional clinical outcomes at the 2-year follow-up.Level of evidenceLevel IV Case series.

Tongue and jaw movement assessed by 3D motion capture during gum chewing.

The tongue plays an important role in mastication, swallowing, and articulation, but it cannot be directly observed because of its location inside the oral cavity. This study aimed to clarify detailed 3D tongue movements during chewing using electromagnetic articulography (EMA). The participants were 10 healthy, young volunteers (average age 26.8 ± 2.1years; 5 males, 5 females). Tongue and jaw movement during gum chewing was measured and recorded using EMA. Four EMA sensors were attached to the anterior, posterior, left, and right surfaces of the tongue, and one sensor was also attached to the mandibular left incisor. The tongue motion during the chewing cycle was spatially and sequentially analyzed based on the motion trajectories of the tongue and mandible. The tongue moved downward and to the masticatory side in a manner similar to the movement of the jaw. The anterior tongue marker moved downward to a greater extent than the other tongue markers. However, the tongue moved forward as the jaw moved backward. The anterior marker reached the most anterior position during the jaw-opening phase and the posterior markers reached the most anterior position during the jaw-closing phase. Just before maximum jaw-opening, all markers on the tongue reached the bottom lowest position. During the jaw-closing phase, the tongue reached the dominant farthest position in the masticatory side. All the markers reached the most posterior position during the occlusal phase. These findings demonstrate the sequence of tongue motion patterns during gum chewing.

Biomechanical study of three-dimensional printed filler block design in open wedge high tibial osteotomy

The use of a filling block can improve the initial stability of the fixation plate in the open wedge high tibial osteotomy (OWHTO), and promote bone healing. However, the biomechanical effects of filling block structures and materials on OWHTO remain unclear. OWHTO anatomical filling block model was designed and built. The finite element analysis method was adopted to study the influence of six filling block structure designs and four different materials on the stress of the fixed plate, tibia, screw, and filling block, and the micro-displacement at the wedge gap of the OWHTO fixation system. After the filling block was introduced in the OWHTO, the maximum von Mises stress of the fixation plate was reduced by more than 30%, the maximum von Mises stress of the tibia decreased by more than 15%, and the lateral hinge decreased by 81%. When the filling block was designed to be filled in the posterior position of the wedge gap, the maximum von Mises stress of the fixation system was 97.8 MPa, which was smaller than other filling methods. The minimum micro-displacement of osteotomy space was -2.9 μm, which was larger than that of other filling methods. Compared with titanium alloy and tantalum metal materials, porous hydroxyapatite material could obtain larger micro-displacement in the osteotomy cavity, which is conducive to stimulating bone healing. The results demonstrate that OWHTO with a filling block can better balance the stress distribution of the fixation system, and a better fixation effect can be obtained by using a filling block filled in the posterior position. Porous HA used as the material of the filling block can obtain a better bone healing effect.

Anterior cruciate ligament reconstruction: Effect of graft tunnel position on early to mid-term clinical outcomes.

Patient reported outcome measures (PROMs) can be used to assess knee function following anterior cruciate ligament (ACL) reconstruction. Intra-operatively, femoral and tibial tunnels are created to accommodate the new ACL graft. It is postulated that there is an optimum position and orientation of these tunnels and that outcomes from this procedure are affected by their position. To evaluate the influence of graft tunnel position on early to mid-term clinical outcomes following ACL reconstruction. Six PROMs were collected following ACL reconstruction which included the Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee, Lysholm, Tegner, EuroQol-5 Dimension-5 level, and Short Form 12-item Health Survey. A total of 8 radiological parameters were measured from post-operative X-rays relating to graft tunnel positions. This data was analysed to assess for any correlations between graft tunnel position and post-operative PROMs. A total of 87 patients were included in the study with a mean post-operative follow-up of 2.3 years (range 1 to 7 years). Posterior position of tibial tunnel was associated with improved KOOS quality of life (rho = 0.43, P = 0.002) and EQ-5D VAS (rho = 0.36, P = 0.010). Anterior position of EndoButton femoral tunnel was associated with an improved EQ-5D index (rho = -0.38, P = 0.028). There were no other significant correlations between any of the other radiological parameters and PROM scores. Overall, graft tunnel position had very little correlation with clinical outcomes following ACL reconstruction. A few (posterior) tibial tunnel and (anterior) EndoButton femoral tunnel measurements were associated with better PROMs.