Insertion Distance Research Articles

How to Set Working Cannula in Endoscopic-Assisted Transforaminal Lumbar Interbody Fusion: A Morphometric Analysis Based on Computed Tomography.

There is a high risk of nerve root injury during endoscopic-assisted transforaminal lumbar interbody fusion (Endo-TLIF). This study used computed tomography (CT) imaging to assess the relationship between the exiting nerve root and its surroundings, and the corresponding intervertebral disc. We also measured the approximate position and angle for the placement of the working cannula to reduce the risk of nerve root injury during Endo-TLIF procedures in the Chinese population. This retrospective study was conducted at our institution between December 2021 and December 2022. A total of 115 patients suffering from low back pain were recruited for the study. For each participant, three-dimensional (3D) vertebral models of the lumbar segments from L3 to S1 were constructed based on their CT images. The nerve root-disc distance, cannula insertion bypass distance and angle, foraminal height and width, exiting nerve root height, and nerve root-pedicle distance were measured. A paired t-test was used to compare measurements between the left and right sides, while inter- and intraobserver reproducibility was assessed using the intraclass correlation coefficient (ICC). From L3/4 to L5/S1 segments, the ideal cannula insertion distance range was 37.51 ± 4.91-120.38 ± 37.71 mm at L3/4; 42.38 ± 5.29-116.25 ± 27.22 mm at L4/5; and 37.78 ± 4.86-69.26 ± 12.64 mm at L5/S1. The appropriate cannula insertion angle range was 30.86° ± 5.05°-62.59° ± 6.66° at L3/4; 34.30° ± 4.73°-60.88° ± 7.34° at L4/5; and 35.89° ± 4.18°-47.65° ± 7.38° at L5/S1. The height of the intervertebral foramen (IVF) gradually decreased, and the width steadily increased. The exiting nerve root height and the nerve root-pedicle distance slightly decreased caudally. From L3/4 to L5/S1, the range of working cannula insertion distance and angle gradually decreased, and the exiting nerve root height occupying the IVF gradually increased. Our measurement can reduce the risk of nerve root injury caused by inserting the working cannula during Endo-TLIF.

Agreement between intraoperative and anterior segment optical coherence tomography measurements of the extraocular muscle insertion distance in patients with previous strabismus surgery

PurposeTo evaluate the agreement between anterior segment optical coherence tomography (AS-OCT) measurement of preoperative distance from the limbus to the horizontal rectus muscles insertion and intraoperative measurement in patients who have previously undergone strabismus surgery and required reoperation. MethodsSubjects from two ophthalmological centers were included. Preoperative AS-OCT was used to measure the muscle insertion from the limbus, and intraoperative measurements were obtained using calipers. Interclass correlation coefficient and Bland-Altman agreement analysis were used. ResultsA total of 53 horizontal rectus muscles from 24 patients with previous strabismus surgery were analyzed: 27 medial rectus (MR) and 26 lateral rectus (LR) muscles, including both previously operated and previously unoperated muscles. Average AS-OCT measurements of MR was 8.54 ± 2.42 mm and intraoperatively was 9.4 ± 3.09 mm. Average AS-OCT for LR was 8.32 ± 2.25 mm and intraoperatively was 9.34 ± 3.73 mm. 63% of MR muscles and 77% of LR muscles were within 1 mm between AS-OCT and intraoperative measurement. Spearman’s correlation coefficient showed positive correlation between measures for both MR and LR muscles. The interclass correlation coefficient was 0.79 (95% CI, 0.56-0.90) for MR muscles and 0.70 (95% CI, 0.44-0.85) for LR muscles, with a good agreement. Agreement was better for muscles ≤10 mm from the limbus (which included both previously operated and unoperated muscles) than for muscles found >10 mm from the limbus. ConclusionsGood agreement was observed between the measurement of limbus-insertion distance obtained by AS-OCT and by intraoperative measurement, especially when the muscle insertion was ≤10 mm from the limbus.

Factors influencing the therapeutic effect of hyperopic correction on esotropia in patients with partially accommodative esotropia.

To collate data on partially accommodative esotropia (PAET) to better understand this condition's aetiology and to evaluate and predict the therapeutic effect of a hyperopic correction on PAET. Eighty-nine consecutive patients diagnosed with PAET with a spherical equivalent (SE) refractive error >+2.50 D were included in this retrospective review. Clinical characteristics, including gender, age, SE, angle of esodeviation, accommodative convergence/accommodation (AC/A) ratio, near-distance disparity (NDD) and anatomical features of the rectus muscles were compared among different PAET subgroups. Multiple linear regression was used to identify independent factors that influenced the therapeutic effect of a hyperopic correction on esotropia. No significant differences were observed for the angle of esodeviation as a function of age in individuals with PAET. The incidence of SE in PAET participants >9 years old was significantly greater than in those <5 and 6-8 years of age. The therapeutic effect of hyperopic correction on esotropia was positively associated with SE both at distance and near. In addition, the limbus insertion distance (LID) of the lateral rectus (LR) muscle was positively associated with NDD at distance, but negatively associated at near. A greater incidence of hyperopia was observed in older (>9 years old) PAET patients. A hyperopic correction had a greater effect on esotropia in individuals with a higher SE, larger LID of the LR muscle and a smaller NDD.

Medial rectus insertion site in cases of acute acquired comitant esotropia associated with excessive digital device usage.

To compare the distance of the medial rectus muscle insertion to the limbus (DMIL) between patients with acute acquired comitant esotropia (AACE) associated with excessive digital device usage (EDDU) and exotropic patients. Retrospective study. The medical records of 72 eyes of 44 patients with EDDU were retrospectively analyzed. The DMIL was measured from the anterior part at the midpoint of the medial rectus muscle insertion into the anterior limbus using a caliper after dissecting the medial rectus muscle with two control sutures at 12 o'clock and 6 o'clock. The DMIL in the non-fixation eye was compared between 44 patients with AACE and 23 patients with exotropia. The mean daily EDDU was 6.5 ± 3.1h. The mean cycloplegic refractive errors (spherical equivalent: SE) were - 3.18 ± 2.52 diopters (D) OD and - 3.03 ± 2.42 D OS. The mean DMIL in the 72 eyes of 44 patients with AACE associated with EDDU was 4.30 ± 0.66mm. The difference in DMIL of non-fixation eyes between 44 AACE patients and 23 exotropic patients was significant (4.28 ± 0.65mm vs. 5.28 ± 0.50mm, p < 0.0001). However, the SE in 44 non-dominant eyes of AACE was - 3.08 ± 2.56 D, significantly stronger than - 1.22 ± 1.93 D in the 23 exotropic eyes (p = 0.008). DMIL in patients with AACE associated with EDDU was significantly shorter. This anatomical anomaly may be an etiology of AACE associated with EDDU.

Exploration of Choroidal Thinning Located Temporal to the Fovea: A Pilot Study.

Background/Objectives: Posterior staphyloma (PS) is a hallmark of pathological myopia, corresponding to a circumscribed outpouching of the eyeball with choroidal thinning and inward scleral deformation at its edges. Its pathogenesis is still unclear, thus constituting a research priority as the prevalence of myopia is increasing worldwide. Recently, it has been suggested that the optic nerve sheaths or oblique muscles are potential promoters of PS through the traction or compression effect that they apply to the eye wall. The inferior oblique muscle (IOM) inserts 1-2 mm from the macula. The projection of its insertion is accessible using Optical Coherence Tomography (OCT). Before launching prospective studies, we sought to detect any choroidal thinning (ChT) in the temporal vicinity of the macula and to measure the distance between it and the fovea (FT-distance). Methods: This retrospective cross-sectional pilot study included 120 eyes. Using Spectralis®-OCT, the area centered by the Bruch's membrane opening-fovea axis was analyzed for ChT and FT-distance. Results: Of the 112 defined eyes, 70% (78 eyes) had ChT. Pachymetry was significantly thinner (p = 0.018) in eyes with than without ChT. The mean FT-distance was 3601.9 ± 93.6 µm. Conclusions: The location of ChT coincided with the insertion distance of the IOM, suggesting a link between them. The association between the presence of ChT and a thinner pachymetry suggests a reduced scleral resistance, as a thinner pachymetry is related to a thinner sclera. Our results suggest a link between ocular deformation and the IOM, which may be relevant for the pathogenesis of PS, warranting further investigation.

Knee rotation in patients with and without patellofemoral instability and its correlation with patellar tendon trochlear groove distance

Background and study aims: There are limited studies assessing the role of “knee rotation” in patellofemoral instability (PFI). Knee rotation is the external rotation of the proximal tibia with respect to distal femur. The study was performed to compare knee rotation, patellar tendon lateralisation and patellar tendon trochlear groove (PTTG) distance measured on MRI between patients with and without PFI and to assess the relative association of these factors with PFI. Materials and methods: It was a retrospective cross-sectional study done on archival MRI films. A sample size of 20 for PFI group and 60 for control group was taken. PTTG distance, knee rotation and lateralisation of patellar tendon insertion were measured as described in literature. The knee rotation and patellar tendon lateralisation between PFI and non-PFI group were compared using t-test and their Pearson’s correlation (r) with PTTG distance was calculated. Relative associations of these factors with PFI were assessed using multivariate regression. Results: Lateralisation of patellar tendon insertion and external knee rotation were both found to be higher in PFI patients as compared to non-PFI patients. However,on taking PTTG distance into consideration, the associations of knee rotation as well as of patellar tendon lateralisation with PFI did not remain significant in generalised linear modeling. Overall, the PTTG distance showed moderate to strong correlation with the external knee rotation as well as with lateralisation of patellar tendon insertion. Conclusions: Knee rotation was found to be significantly higher in PFI patients as compared to controls. However, PTTG distance appears to be a composite measure that takes into account the influence of both the patellar tendon lateralisation as well as knee rotation on patellofemoral biomechanics.

Internal surface inspection method under linear structured light illumination based on dual non-coaxial optical paths

The inner space of tubular and hole-like workpieces, such as oil pipes and cylinders, is limited in volume and has no effective means of measuring the inner surface under geometric constraints.This paper proposes a non-coaxial optical path line structured light method for inner surface inspection, which can significantly reduce the device size and working distance. The method constructs two non-coaxial optical paths for light source and imaging, and uses two fixed reflectors to achieve the deflection of the optical axes of the light source and imaging paths.After theoretical derivation and verification, a sample device was designed and fabricated for experiments. The device measures approximately 22 mm by 24 mm in cross-section, the maximum insertion distance is about 200 mm, and the minimum inner diameter of the accessible space is 50 mm.The results show that the optical path design does not destroy the original homography relationship, and can still ensure the measurement capability comparable to the existing methods when reducing the device size to 10% of the original. The method has obvious advantages when applied to the inspection of tubular and hole-like workpieces in fields such as petrochemical industry, military equipment, etc.

Evaluation of an impedance-based method to monitor the insertion of the electrode array during cochlear implantation

PurposeCochlear implantation is a prevalent remedy for severe-to-profound hearing loss. Optimising outcomes and hearing preservation, and minimising insertion trauma, require precise electrode placement. Objective monitoring during the insertion process can provide valuable insights and enhance surgical precision. This study assesses the feasibility and performance of an impedance-based method for monitoring electrode insertion, compared to the surgeon’s feedback.MethodsThe study utilised the Insertion Monitoring Tool (IMT) research software, allowing for real-time measurement of impedance and evoked compound action potential (eCAP) during electrode insertion in 20 patient implantations. This enabled an impedance-based method to continuously assess the status of each electrode during the insertion process. The feasibility and performance was evaluated and compared to the surgeon’s feedback approach. eCAP measurements focused merely on feasibility without searching specific responses.ResultsThe IMT demonstrated feasibility in measuring real-time impedances and eCAP during the insertion of the electrode array. The impedance-based method exhibited potential for accurately monitoring the insertion depth with a high success rate. However, further development is needed to improve the number of usable contacts.ConclusionsObjective monitoring with the impedance-based method shows promise as a valuable tool to enhance the precision of cochlear implant electrode insertion respecting insertion distance estimation. The IMT research software proved feasible in recording real-time impedances and eCAP during electrode insertion. While this impedance-based method exhibits high success rates, further improvements are required to optimise the number of usable contacts. This study highlights the potential of objective monitoring techniques to enhance cochlear implantation outcomes.

Anatomy of the Lumbrical Muscles: Implications for Mechanical Advantage.

The lumbrical muscles comprise 4 intrinsic muscles of the hand and are involved in flexion of the metacarpophalangeal joint (MCPJ) and extension of the proximal interphalangeal and distal interphalangeal joints. The purpose of this study was to investigate the anatomical mechanics of the lumbrical muscles of the index, middle, ring, and small fingers. We evaluated 25 cadaver arms and measured the distance between the MCPJ and fingertip, the distance between the MCPJ and lumbrical muscle insertion, and the distance between the MCPJ and the most proximal lumbrical muscle origin. With these measurements we calculated the needed force, insertion ratio (length of the proximal, middle, and distal phalanx divided by the MCPJ to insertion distance), and lumbrical muscle length. We found that the force was significantly different between all fingers, except for the comparison of the index and ring finger (P = .34). In addition, we found that muscle length was significantly different between most the fingers, except for the comparison between the index and middle fingers (P = .24), and index and ring fingers (P = .20). There was no significant difference in insertion ratio. Our study suggests that the anatomical mechanics for the motor function of the lumbrical muscles are similar in all fingers. This could further imply that movements are equally precise in all fingers resulting in coordination with one another and, therefore, adequate hand function. IV.

Biomechanical Comparison of Uniplanar versus Biplanar Lateral Opening-wedge Distal Femoral Osteotomy Techniques in Terms of Risk for Medial Hinge Fracture.

The effect of osteotomy type on the initial stiffness of the bone-implant construct in lateral opening-wedge distal femoral osteotomy (LOWDFO) using a uniplanar compared with a biplanar technique has been investigated. However, no study has explored the biomechanical risk factors for medial hinge fracture. This study aimed to compare the biomechanical strength of uniplanar versus biplanar LOWDFO regarding the risk for medial hinge fracture during gap opening. Twelve composite femora were divided into two groups (six in each group) based on the distal femoral osteotomy technique: uniplanar versus biplanar LOWDFO. All LOWDFO models were subjected to incremental static loading. The gap distance was expanded by 1 mm, and displacement values were recorded as anterior and posterior gap distances (mm). The average force values of all samples at certain gap distances were recorded, and the head distance was measured. The uniplanar group had higher load values than the biplanar group at all anterior gap distances. These differences were only significant at 2- and 3-mm gap distances (p = 0.025 and 0.037). At all posterior gap distances, the uniplanar group had higher load values than the biplanar group, but these differences only reached statistical significance at 2 mm (p = 0.037). Both groups had similar anterior, posterior, and average gap distances (p = 0.75, 0.522, 0.873). The uniplanar group had a higher head insertion distance (15.3 ± 5.7) than the biplanar group (14.7 ± 2.9), but it was not significant (p = 0.87). The uniplanar group had a lower average load before medial hinge fracture (46.41 ± 13.91 N) than the biplanar group (54.92 ± 31.94, p = 0.81). The biplanar group had an average maximum load value of 64.18 ± 25.6 N, while the uniplanar group had 57.90 ± 12.21 N (p = 0.81). This study revealed that the biplanar osteotomy technique allows a wider opening wedge gap with less risk of a medial hinge fracture than uniplanar LOWDFO.Level of evidence was level 3, case-control series.

Effect of aromatherapy with peppermint essential oil on the gag reflex: a randomized, placebo-controlled, single-blind, crossover study

BackgroundSensitive gag reflexes prevent dental patients from receiving appropriate treatment. Aromatherapy helps patients relax during dental procedures. However, the effect of aromatherapy on the gag reflex caused by the stimulation of the oral cavity is unknown. This study aimed to evaluate whether aromatherapy reduces gag reflexes during oral stimulation.MethodsIn this randomized, placebo-controlled, single-blind, crossover study, the gag reflexes of 24 healthy individuals (12 females and 12 males; mean age: 34.3 ± 9.5 years) were quantified. A standard saliva ejector was slowly guided down the participant’s throat to determine the maximum tolerance of the gag reflex, and the insertion distance was measured to quantify the gag reflex. All individuals participated in an aromatherapy session with peppermint essential oil and a placebo session with distilled water. The gag reflex was quantified before (baseline) and after each session. Another measurement was performed using nitrous oxide/oxygen inhalation as a positive control.ResultsGag reflex values significantly increased after aromatherapy with both peppermint essential oil and placebo compared to baseline values (paired t-test, P < 0.001 and P = 0.014, respectively). The gag reflex value also increased significantly during nitrous oxide/oxygen inhalation (paired t-test, P < 0.001). There was no significant difference in the increase rate of gag reflex values between the positive control and aromatherapy interventions, but it was significantly lower after the placebo intervention (repeated measures analysis of variance, P = 0.003; post-hoc test, P = 0.83 and P = 0.02).ConclusionAromatherapy with peppermint essential oil has the potential for reducing gag reflex during dental procedures.Trial registrationThe study was registered in the University hospital Medical Information Network Clinical Trials Registry under the code UMIN000050616 (approved 17/03/2023).

Characterization of the length and the distance of insertion of the branches of apple trees

The current study focused on the branches Cherry Gala variety of apple in Azrouregion.The objective is to characterize the length and the insertion distance of different structures of apple trees based on nondestructive and exhaustive measurements of the branches. In total 2982 branches were identified and measured in the two stages (stage 1, stage 2) on different 6 levels present at each stage known as A, B, C, D, E, and F. The length of the branches in each stage and level was classified into 1 to 5 homogeneous classes. The length of vegetative branch variation was not significant between stages 1 and 2 but the insertion distance was significant for level D and not for levels A, B, and C. For five different length structures bearing fruit, the variation was significantly different for B, C, and D levels between stages 1 and 2 (length of fruiting spurs/ Dard/ Bourse; insertion distance of Dard and Bourse). The analysis showed that the length of the branches decreases while passing from one first stage to the second. The average branch length for stage 1 is 4,84 cm against 4,05 cm for stage 2. In each stage, the length decreases progressively while passing from one level to a higher level, except for level E of stage 1 and levels E and F of stage 2.

Kinematic and Morphometric Assessment of Fresh Semen, before, during and after Mating Period in Brahman Bulls.

The objective of the present study was to determine the effects that the reproductive season has on the motility, kinematics, morphology, and sperm morphometry of Brahman bulls evaluated with a commercial CASA system. The experiment was carried out at the Costa Rica Institute of Technology from March to August 2021. A total of eight Brahman bulls were used. A total of 28 ejaculates were collected in the pre-mating period (PMP), during it (DMP), and after it (AMP) using an electroejaculator. The sperm concentration was measured with the Accuread photometer. The motility was measured using a Spermtrack® counting chamber. The analyses were performed with the CASA-Mot ISAS®v1 system. The morphology was analyzed using a microscope with a negative phase contrast objective. Morphometry was evaluated with the CASA-Morph. The sperm concentration did not present differences between the PMP and AMP; however, it was significantly higher than DMP (p > 0.05). Regarding the progressiveness variables, linearity on forward progression (LIN), straightness (STR), and wobble (WOB) were higher (p < 0.05) DMP. A kinematic principal component analysis grouped all the variables into three factors and an effect on the reproductive period was found (p < 0.05) in the parameters of the head and middle part of the sperm, such as width and perimeter, which were greater in the PMP. The length of the sperm head in the PMP and DMP did not show differences; however, both were larger (p < 0.05) than AMP. The insertion distance of the middle piece of the sperm was significantly greater than DMP. Finally, the PMP contained cells with a larger insertion angle (p < 0.05) than AMP. These findings are important to understand the implications of reproductive status on sperm quality and to consider them in andrological evaluations.

Flexor hallucis longus. A cadaveric study of its distal insertion

Objective: Describe flexor hallucis longus (FHL) distal insertion. Methods: Ten cadaver feet were dissected to evaluate FHL distal insertion, the width of insertion, and the distance between insertion borders and medial-lateral phalangeal borders. Results: All specimens showed a lateral tendon fascicle inserted more lateral and distal than the main insertion. The mean lateral and medial insertion distance to the phalangeal border was 3 mm and 5.2 mm. The FHL long axis was 12.36% laterally deviated at the metatarsophalangeal (MTP) joint and 14.07% at the interphalangeal (IP) joint. Conclusion: The FHL has a closer insertion to the lateral phalanx border, and its long-axis midpoint is laterally located in relation to the IP and MTP joint. The detailed knowledge of the FHL true anatomy. The discovery of a lateral deviated axis, a lateral fascicle, and a lateral footprint.

A Randomized Clinical Trial to Compare Three Different Methods for Estimating Orogastric Tube Insertion Length in Newborns: A Single-Center Experience in China.

Background: Orogastric (OG) and nasogastric (NG) tubes are frequently used in the NICU. Obtaining a relatively accurate estimated length before insertion could significantly reduce complications. While previous studies have mainly focused on the NG tube, OG tubes are more commonly used in China. Purpose: The objective was to determine whether there were differences in the rate of accurate placement among the adapted nose-ear-xiphoid (NEX) method, nose-ear-midway to the umbilicus (NEMU) method, and weight-based (WB) equation in estimating the OG tube insertion distance. Methods: A randomized, controlled, open-label clinical trial to compare the three methods was conducted in a single center. After enrollment, newborns were randomly assigned into three groups. By radiological assessment, the anatomical region for OG tube placement was analyzed. The primary metric was the tip within the gastric body, and the second metric was strictly accurate placement defined as the tube was not looped back within the stomach and the end was located more than 2 cm but less than 5 cm into the stomach, referred to as T10. Results: This study recruited 156 newborns with the majority being preterm infants (n = 96; 61.5 percent), with an average birth weight of 2,200.8 ± 757.8 g. For the WB equation, 96.2 percent (50 cases) of the OG tubes were placed within the stomach, and the rates were 78.8 percent (41 cases) in the adapted NEX and NEMU methods. The strictly accurate placement rates were highest for the WB equation at 80.8 percent (42/52), followed by the adapted NEX method at 65.4 percent (34/52), and the NEMU method at 57.7 percent (30/52). Conclusion: The WB equation for estimating the insertion depth of the OG tube in newborn infants resulted in more precise placement compared to the adapted NEX and NEMU methods.

Reversal and Transposition Distance on Unbalanced Genomes Using Intergenic Information.

The most common way to calculate the rearrangement distance between two genomes is to use the size of a minimum length sequence of rearrangements that transforms one of the two given genomes into the other, where the genomes are represented as permutations using only their gene order, based on the assumption that genomes have the same gene content. With the advance of research in genome rearrangements, new works extended the classical models by either considering genomes with different gene content (unbalanced genomes) or including more genomic characteristics to the mathematical representation of the genomes, such as the distribution of intergenic regions sizes. In this study, we study the Reversal, Transposition, and Indel (Insertion and Deletion) Distance using intergenic information, which allows comparing unbalanced genomes, because indels are included in the rearrangement model (i.e., the set of possible rearrangements allowed when we compute the distance). For the particular case of transpositions and indels on unbalanced genomes, we present a 4-approximation algorithm, improving a previous 4.5 approximation. This algorithm is extended so as to deal with gene orientation and to maintain the 4-approximation factor for the Reversal, Transposition, and Indel Distance on unbalanced genomes. Furthermore, we evaluate the proposed algorithms using experiments on simulated data.

Elbow Kinematics and Function Following Treatment with Open Arthrolysis and Hinged External Fixator.

Open arthrolysis (OA) combined with hinged external fixator (HEF) is a promising surgical option for patients with elbow stiffness. This study aimed to investigate elbow kinematics and function following a combined treatment with OA and HEF in elbow stiffness cases. Patients treated with OA with or without HEF due to elbow stiffness were recruited between August 2017 and July 2019. Elbow flexion-extension motion and function (Mayo elbow performance scores, MEPS) were recorded and compared between patients with and without HEF during a 1-year follow-up period. Additionally, those with HEF were assessed by dual fluoroscopy at week 6 postoperatively. Flexion-extension and varus-valgus motions, as well as ligament insertion distances of the anterior medial collateral ligament (AMCL) and lateral ulnar collateral ligament (LUCL), were compared between the surgical and intact sides. This study included 42 patients, of which 12 with HEF demonstrated a similar flexion-extension angle and range of motion (ROM) and MEPS as the other patients. In patients with HEF, the surgical elbows showed limitations in flexion-extension (maximal flexion, 120.5° ± 5.3° vs 140.4° ± 6.8°; maximal extension, 13.1° ± 6.0° vs 6.4° ± 3.0°; ROM, 107.4° ± 9.9° vs 134.0° ± 6.8°; all Ps < 0.01) compared with the contralateral sides. During elbow flexion, a gradual valgus-to-varus transition of the ulna, increase in the AMCL insertion distance, and steady change in the LUCL insertion distance were observed, with no significant differences between the bilateral sides. Patients treated with OA and HEF demonstrated similar elbow flexion-extension motion and function to those treated with OA alone. Although the use of HEF could not restore an intact flexion-extension ROM and might result in some minor but not significant changes in kinematics, it contributed to clinical outcomes comparable to that of the treatment with OA alone.

The effect of subtalar joint axis location on muscle moment arms

Most dynamic musculoskeletal models define the subtalar joint (STJ) as a one degree of freedom (DOF) hinge with a tri-planar axis. The orientation of this axis of rotation is often determined as a combination of inclination and deviation angles measured from the ground and midline of the foot, respectively. In defining the location of the axis, often the origin is found at the distal aspect of the heel instead of at the articulation of the talus and calcaneus. Key musculoskeletal modeling definitions, such as muscle moment arms, are dependent on the distance and relative location of muscle insertion to the axis of rotation. Since the axis orientation and origin location affect calculations of muscle moment arm and joint dynamics, there is much need for accurate characterization of the STJ axis to understand the STJ’s role in dynamic weight-bearing motion. The purpose of this study is to explore how the STJ origin location and axis orientation affect muscle moment arms surrounding the ankle. Datasets from the Grand Knee Challenge, posted on the open-source SimTK website, were modeled using OpenSim. Modifying the location of the STJ axis from the original location closer to the articulation between the talus and calcaneus resulted in significant differences in STJ muscle moment arms and peak STJ moments. The findings of this study conclude that the location of the STJ axis origin needs to be considered and accurately defined, especially if the inclination/deviation angles of the rotational axis will be modified to represent a more subject-specific definition.

Predictors of dual demise within the first week after selective cord occlusion via radiofrequency ablation for complex monochorionic pregnancies

Selective cord occlusion is an option in complicated monochorionic multiple gestations with the goal of reducing the pregnancy by one fetus and to optimize the outcomes for the remaining fetus(es). This study aimed to determine the rate and associated risk factors of dual demise in complex monochorionic pregnancies after selective cord occlusion via radiofrequency ablation. This was a single-center analysis of a prospective registry cohort of complex monochorionic pregnancies managed with selective cord occlusion via radiofrequency ablation between 2014 and 2021. A total of 167 pregnancies met the inclusion criteria and were evaluated on the basis of the intended outcome of dual demise vs singleton survival. Risk factors were compared between the 2 groups. The Mann-Whitney U test was used for continuous variables and the Fisher exact test was used for categorical variables. The incidence of postprocedure dual demise within the first week after performing radiofrequency ablation was 10.8% (18/167). The risk was higher in pregnancies undergoing radiofrequency ablation for discordant anomaly, and this subcategory constituted 38.9% of pregnancies in the dual demise subgroup (P=.02). Lower intertwin estimated fetal weight discordance (P=.01) was associated with dual demise. Perioperative variables including gestational age at procedure, placental cord insertion distance, operative time, and radiofrequency ablation time were similar in those with and without dual demise. Our results show that selective cord occlusion via radiofrequency ablation is a safe and reasonable option in complicated monochorionic pregnancies, with low rates of dual demise within the first week after the procedure.

An Exploratory Investigation of the Palatoglossus Muscle in Children Using Magnetic Resonance Imaging.

There is currently little evidence reporting the typical morphology of the palatoglossus (PG) muscle. The primary purpose of this exploratory study is to determine whether magnetic resonance imaging (MRI) methods used to quantify the morphology of the levator veli palatini (LVP) muscle can be applied to the PG. The secondary purpose is to provide preliminary data regarding the relationship between the LVP and PG muscles in children. Ten children between ages of 4 and 7 years participated in this study. Each participant was scanned using a nonsedated, child-friendly protocol with a T2-weighted, three-dimensional anatomical scan to obtain images of the oropharyngeal anatomy. Custom, oblique-coronal image planes were created to visualize and measure the LVP and PG muscles in their entirety from origin to insertion. Thermo Scientific Amira Software was used to obtain 2D measurements of PG muscle length, width, velar insertion distance, lingual insertion distance, and several angle measurements. The PG ranged from 17.95 to 26.96 mm in length across participants. Velar insertion distance ranged from 17.22 to 30.95 mm. Lingual insertion distance ranged from 26.91 to 36.02 mm. Width ranged from 2.32 to 3.08 mm. The angle formed by the PG and LVP muscle planes ranged from 7.3° to 52.7°. The LVP insertion angle ranged from 42.5° to 75.9°. The PG insertion angle ranged from 16.9° to 52.3°. MRI was successful in visualizing the PG muscle. The PG was consistent in size and shape within an individual participant but varied across the participant cohort.