Distal Connection Research Articles

Finite Element Study on Stability in the Femoral Neck and Head Connection to Varying Geometric Parameters with the Relates Implications on the Effect of Wear

Total hip arthroplasty (THA) is a common surgical procedure used to treat hip osteoarthritis and other joint conditions that cause pain and functional limitation. Traditionally, THA has been performed most often in elderly patients, but in recent years, there has been an increase in hip arthroplasties in young patients. Femoral prosthesis rupture is a rare but significant complication that can also occur in young patients undergoing total hip arthroplasty (THA). Some of the factors that can contribute to femoral prosthesis ruptures include abnormal overload, defects in the design, lack of geometric fit, and type of materials used in the stem and femoral head connection. The aim of this study is to analyze the criticalities in the contact between the femoral head and the stem neck. In particular, two types of contacts will be taken into consideration: proximal and distal, and through the finite element method (FEA), the criticalities will be defined. The results show that in the proximal contact, the stress levels exceeded 500 MPa in certain areas of the prosthesis. This stress could potentially lead to structural failure, such as rupture or deformation of the prosthesis. In addition, to prevent bacterial infiltration or debris from the outside, the distal connection is recommended.

Assessing the impact of blocking distal coronary sinus-left atrial muscular connection on inducible rate of atrial fibrillation and follow-up recurrence in persistent atrial fibrillation patients with different fibrotic degrees of left atrial: A retrospective study.

BackgroundThe musculature of the coronary sinus (CS), especially its distal connection with the post wall of the left atrial (LA), has been associated with the genesis and maintenance of atrial flutter (AFL) and atrial fibrillation (AF). However, the relative contributions of the distal coronary sinus (CSD)-LA connection to PersAF with various degrees of atrial fibrosis remain unknown.ObjectiveThis study aimed to explore the different roles of blocking the CSD-LA connection in the induction of acute AF and middle-term follow-up of recurrence among PersAF patients with various degrees of LA fibrosis.Methods and resultsA retrospective cohort of 71 patients with drug-refractory and symptomatic PersAF underwent ablation for the first time were studied. The population was divided into two groups according to disconnection of the CSD-LA or not. All patients enrolled accepted the unified ablation procedure (circumferential pulmonary vein isolation, non-pulmonary vein trigger ablation and ablation of the CSD-LA connection). Group A (n = 47) successfully blocked the CSD-LA electrical connection and Group B (n = 24) failed. Twenty-five patients could be induced into sustained AF in the Group A compared to 20 in the Group B (53.2 vs. 83.3%, p = 0.013). After a mean follow-up of 185 ± 8 days, 24 (33.8%) patients experienced atrial arrhythmia recurrences. The Group A had significantly fewer recurrences (25.5%) compared to Group B (50%). Meanwhile, in Group A, the ROC curve analysis suggested that in the case of blocking CSD-LA, low voltage area (LVA) of LA can act as a predictive factor for acute AF induction (AUC = 0.943, Cut-off = 0.190, P < 0.001) with sensitivity and specificity of 92.3 and 90.5%, and middle-term recurrence (AUC = 0.889, Cut-off = 0.196, P < 0.001) with sensitivity and specificity of 100 and 65.7%.ConclusionDisconnection of CSD-LA could reduce the inducible rate of acute AF and the recurrences of atrial arrhythmia during middle-term follow-up. The PersAF patients with CSD-LA muscular connection blocked, experienced a higher acute AF inducible rate with larger proportion of LVA of LA (≥19%) and a higher recurrent rate of atrial arrhythmias with a larger proportion of LA fibrosis (≥19.6%).

High 3He/4He in central Panama reveals a distal connection to the Galápagos plume

It is well established that mantle plumes are the main conduits for upwelling geochemically enriched material from Earth's deep interior. The fashion and extent to which lateral flow processes at shallow depths may disperse enriched mantle material far (>1,000 km) from vertical plume conduits, however, remain poorly constrained. Here, we report He and C isotope data from 65 hydrothermal fluids from the southern Central America Margin (CAM) which reveal strikingly high 3He/4He (up to 8.9RA) in low-temperature (≤50 °C) geothermal springs of central Panama that are not associated with active volcanism. Following radiogenic correction, these data imply a mantle source 3He/4He >10.3RA (and potentially up to 26RA, similar to Galápagos hotspot lavas) markedly greater than the upper mantle range (8 ± 1RA). Lava geochemistry (Pb isotopes, Nb/U, and Ce/Pb) and geophysical constraints show that high 3He/4He values in central Panama are likely derived from the infiltration of a Galápagos plume-like mantle through a slab window that opened ∼8 Mya. Two potential transport mechanisms can explain the connection between the Galápagos plume and the slab window: 1) sublithospheric transport of Galápagos plume material channeled by lithosphere thinning along the Panama Fracture Zone or 2) active upwelling of Galápagos plume material blown by a "mantle wind" toward the CAM. We present a model of global mantle flow that supports the second mechanism, whereby most of the eastward transport of Galápagos plume material occurs in the shallow asthenosphere. These findings underscore the potential for lateral mantle flow to transport mantle geochemical heterogeneities thousands of kilometers away from plume conduits.

Whole genome sequencing of familial isolated oesophagus atresia uncover shared structural variants

BackgroundOesophageal atresia (OA) is a life-threatening developmental defect characterized by a lost continuity between the upper and lower oesophagus. The most common form is a distal connection between the trachea and the oesophagus, i.e. a tracheoesophageal fistula (TEF). The condition may be part of a syndrome or occurs as an isolated feature. The recurrence risk in affected families is increased compared to the population-based incidence suggesting contributing genetic factors.MethodsTo gain insight into gene variants and genes associated with isolated OA we conducted whole genome sequencing on samples from three families with recurrent cases affected by congenital and isolated TEF.ResultsWe identified a combination of single nucleotide variants (SNVs), splice site variants (SSV) and structural variants (SV) annotated to altogether 100 coding genes in the six affected individuals.ConclusionThis study highlights rare SVs among candidate gene variants in our individuals with OA and provides a gene framework for further investigations of genetic factors behind this malformation.

Modified Distal Dunk Technique for Right Ventricle to Pulmonary Artery Shunt in Stage 1 Palliation

Although the use of a right ventricle to pulmonary artery shunt as a source of pulmonary blood flow in stage 1 Norwood palliation is common, there is no uniform agreement on the optimal surgical technique. We present a technique for creating the distal connection aimed at minimizing procedural bleeding, promoting distal patency, and facilitating second-stage palliation.

Description of the Tadpole ofPseudopaludicola cangaGiaretta and Kokubum, 2003 (Anura: Leptodactylidae)

We describe the external morphology, internal oral anatomy, and chondrocranium of Pseudopaludicola canga. The tadpole is diagnosed by the following combined characters: elliptic body, reniform nostril, dorsal fin starting at the body-tail junction and labial tooth row formula 2(2)/2(1) presenting two lateral gaps in the marginal papillae of the lower lip. Regarding the oral cavity, there is a pattern similarity in some characters among the three species of the genus for which the structure has been described; however, P. canga can be characterized by having a pair of infralabial papillae, irregular median ridge, three lingual papillae, fewer papillae in the buccal roof arena, and greater number of papillae in the buccal floor. The chondrocranium of P. canga differs from that of P. boliviana by presenting a distal connection between the pars alaris and pars corporis of the cartilago suprarostralis; and differs from P. falcipes by lacking a processus pseudopterygoideus. Further, our data emphasize the utility of larval characters as additional tools in the diagnosis of species within this genus.

The anatomy and clinical applications of flexor hallucis longus tendon transfer in treatment of chronic Achilles tendinopathy

Objective To evaluate the effectiveness of flexor hallucis longus tendon transfer in treatment of chronic Achilles tendinopathy using different technique. Methods Sixty-four embalmed feet of 32 cadavers were analyzed and classified anatomically with respect to the individual cross links in the Henry's knot. These three techniques were then combined to determine the total potential tendon graft length obtainable using single incision, double incision and minimally invasive incision. From January, 2012 to June, 2015, 10 patients (10 feet) with chronic Achilles tendinopathy were treated with double incision technique. The score was 63.04 ±7.75 according to American Orthopedic Foot and Ankle Society (AOFAS) ankle and hindfoot score system. Results Only two different configurations were found. Type 1, a tendinous slip branched from the FHLT to the FDLT was 96.9% (62 of 64 feet) . Type 2, a slip branched from the FHLT to the FDLT and another slip from the FDLT to FHLT was 3.1% (2 of 64) . The average length of the FHLT graft available from a single incision measured (5.08±1.09) cm, double incision technique measured (6.72 ± 1.02) cm, and minimally invasive incision measured (17.49 ± 1.80) cm. The difference between the lengths obtained from these three techniques was statistically significant. Ten patients were followed-up 12-36 months (mean, 13.7 months) . At 12 months after operation, the AOFAS ankle and hindfoot score was 93.28 ± 3.72, showing significant difference when compared with that before operation. The results were excellent in 6 cases, good in 3 cases, and fair in 1 case with an excellent and good rate of 90%. No sural nerve injury, posterior tibial nerve injury, medial plantar nerve injury, and lateral plantar nerve injury occurred. Conclusion In over 96% of the feet, a proximal to distal connection from the FHLT to the FDLT was found, which might contribute to the residual function of the lesser toes after FDLT transfer. The distal stump of the FHLT tendon should be sutured onto the FDLT tendon under tension to enable a co-activation of the great toe, preserved hallux plantar flexion. Chronic Achilles tendinopathy reconstruction with flexor hallucis longus tendon harvested using double incision technique offers a desirable outcome in operative recovery, tendon fixation, preserved hallux plantar flexion and less complications. Key words: Flexor hallucis longus; Flexor digitorum longus; Achilles tendon disorders; Tendon transfer

Association Among Gut Microbes, Intestinal Physiology, and Autism

Autism spectrum disorder (ASD) is a set of neurodevelopmental disorders characterized by two core symptoms: social deficits and increase in stereotypic/repetitive behaviors. Along with the core symptoms of ASD, other comorbid conditions can be observed in certain populations of people with ASD, such as gastrointestinal (GI) complications and altered gut microbiome (Adams et al., 2011 ; Parracho et al., 2005). Homeostasis of the GI system is closely regulated by the gut microbiota. Therefore, whether the gut microbiota is a contributing factor for ASD has been postulated recently. Several key questions have been raised. Do gut microbes contribute to the behavioral symptoms in ASD? How do gut microbes affect behavioral output through the gut–brain axis? How do gut and brain communicate with each other? Due to the complexity of the distal connection between gut and brain, these are the key questions that remain unanswered in the field.

Anatomical study for flexor hallucis longus tendon transfer in treatment of Achilles tendinopathy.

The purpose of the study was to describe the anatomical variations of the connection between the flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendons in the knot of Henry in Asians, and quantify the length of FHL tendon graft with different incisions. Sixty-four embalmed feet of 32 cadavers were analyzed anatomically with respect to the individual cross-links in the planta pedis. Single incision technique graft length was measured from the musculotendinous junction of FHL and the point at sustentaculum tali. Double incision technique was measured from musculotendinous junction of FHL and the level of the master knot of Henry. Additionally, minimally invasive incision technique was measured from musculotendinous junction of FHL to the first interphalangeal joint. These three techniques were then combined to determine the total potential tendon graft length obtainable using different approach. Only two different configurations were found. Type 1, a tendinous slip branched from the FHL to the FDL (62 of 64 feet). Type 2, a slip branched from the FHL to the FDL and another slip from the FDL to FHL (2 of 64). The average length of the FHL graft available from a single incision measured 5.08 cm (range 3.32-10.35, SD = 1.09), double incision technique measured 6.72 cm (range 4.69-12.09, SD = 1.03), and minimally invasive incision measured 17.49 cm (range 13.51-20.52, SD = 1.80). The difference between the lengths obtained from these three techniques was statistically significant (p < 0.001). The absence of no attachment and FDL tendon to the FHL between the two tendons in the foot may be more frequent than previously reported. Only two configurations of the anatomical relationship were found in this study. In over 96 % of the feet, a proximal to distal connection from the FHL to the FDL was found, which might contribute to the residual function of the lesser toes after FDL transfer.

Anatomical Variations of the Flexor Hallucis Longus and Flexor Digitorum Longus in the Chiasma Plantare

The flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendon are routinely used in reconstructive foot and ankle surgery. The tendons cross in the chiasma plantare and show variable interconnections. This can complicate harvesting of the tendons. Previous anatomical studies were inconclusive and did not reference the connections to surgically relevant landmarks. The purpose of this study was to integrate these conflicting results, introduce a thorough classification system, and analyze the position of the interconnections relative to the surgically relevant bone landmarks. Sixty embalmed feet of 30 cadavers were analyzed anatomically with respect to the individual cross-links in the planta pedis. All feet were photo documented. The interconnections were classified in a modified classification system and distances to surgically relevant anatomic landmarks measured. A proximal to distal connection from the FHL to the FDL was found in 95% of the feet (types I and III), in 3% there was a proximal to distal connection from the FDL to the FHL (type II) tendon only, and in 30% a crossed connection (type III) was found. The average point of branching of the FHL and FDL tendon was 5.3 and 4.6 cm distal to the medial malleolus, respectively. Our modified classification system accommodated all found variations. In over 90% of the feet, a proximal to distal connection from the FHL to the FDL was found, which might contribute to the residual function of the lesser toes after FDL transfer. The exact knowledge of the anatomy of the crossing of FDL and FHL in the plantar foot is essential to facilitate tendon harvesting, reduce morbidity and explain possible postoperative functional loss.

Internal features of larvae belonging to two species of Pseudopaludicola (Anura: Leiuperinae)

We described the buccal cavity, chondrocranium, and cranial muscles in tadpoles of two species of Pseudopaludicola: P. boliviana (P. pusilla species group) and P. falcipes. The two species share states of only three relevant and informative characters: (1) absence of m. levator mandibularis lateralis, (2) absence of m. levator mandibularis externus superficialis at advanced premetamorphic stages, and (3) presence of long lateral arena papillae of both the roof and floor of the buccal cavity. The larvae of P. falcipes is diagnosed by (states of P. boliviana between parentheses): (1) three lingual papillae (four), (2) one-two pairs of short and blunt infralabial papillae (single pair of multifid papillae), (3) low median ridge (tall), (4) distal connection between pars corpora and pars alaris of the cartilago suprarostralis present (absent), and (5) m. subarcualis rectus II-IV inserted at ceratobranchiale I (ceratobranchiale II insertion). The combination of a processus pseudopterygoideus together with proximal and distal connections on the cartilago suprarostralis occurs in most species of Pleurodema as well. Absence of m. levator mandibularis lateralis is also known for Physalaemus fernandezae and absence of m. levator mandibularis externus superficialis at advanced stages of development (Stage 39 onward) is shared with Edalorhina perezi and Pleurodema diplolister.

External Morphology, Chondrocranium, Cranial Muscles, and Buccopharyngeal Features of Tadpoles of Pleurodema thaul (Anura: Leiuperidae): a Comparison with P. bufoninum

This article describes the external and buccopharyngeal morphology, chondrocranium, and cranial muscles in tadpoles of Pleurodema thaul from Argentina. Further comparison was made with larvae of other Pleurodema species, particularly P. bufoninum. The larvae of P. thaul possess: (1) tooth row formula 2(2)/3(1), (2) single to double row of marginal papillae with wide rostral gap, (3) presence of long processus pseudopterygoideus, (4) pars alaris and pars corpora of the cartilago suprarostralis joined by both proximal and distal connections, and (5) larval processus oticus present. In the light of the available evidence, the larvae of Pleurodema are characterized by (1) medium size (total length = 35.4–48.7 mm); (2) medium-sized tail (0.63 times of total length); (3) rounded snout; (4) nostrils closer to the eyes than to the snout; (5) vent tube opening medial; (6) tail tip rounded; and (7) oral disc subterminal with angular constrictions and rostral gap present. In Leiuperidae, the cartilaginous distal connection between pars alaris and pars corpora of the cartilago suprarostralis is present only in Pleurodema. In addition, all Pleurodema studied to date have processus pseudopterygoideus (shared with Eupemphix and Physalaemus marmoratus). Finally, within Pleurodema, the larval processus oticus is present only in P. thaul and P. bufoninum.

Electrophysiological characteristics of the Marshall bundle in humans

Marshall bundles (MBs) are the muscle bundles within the ligament of Marshall. This trial sought to the electrophysiological characteristics of the MB and the anatomical connections between MB and left atrium (LA) in patients with persistent atrial fibrillation (AF). We enrolled 72 patients (male:female 59:13, age 59.9 +/- 9.4 years) who underwent MB mapping and ablation for AF. MB mapping was done via an endocardial or epicardial approach during sinus rhythm and AF. Recordings were successful in 64 of 72 patients (89%). A single connection was noted in 11 of 64 patients between the MB and the coronary sinus (CS) muscle sleeves. The MB recordings showed distinct MB potentials with a proximal-to-distal activation pattern during sinus rhythm. During AF, organized passive activations and dissociated slow MB ectopic activities were commonly observed in this type of connection. Double connections to both CS and LA around left pulmonary veins were noted in 23 of 64 patients (36%). After the ablation of the distal connection, MB recording showed typical double potentials as in single connection. Multiple connections were noted in 30 of 64 patients (47%). During sinus rhythm, the earliest activation was in the middle of the MB. The activation patterns were irregular and variable in each patient. During AF, rapid and fractionated complex activations were noted in all patients of this group. We documented 3 different types of MB-LA connections. Rapid and fractionated activations were most commonly observed in the MB that had multiple LA connections.

Persistent fifth aortic arch

FIGURE 1. Aortogram in the frontal view shows a large vessel, the persistent fifth aortic arch (arrow), arising from the distal ascending aorta and joining the pulmonary artery confluence. Persistence of the fifth aortic arch (PFAA) is a rare condition that results in the presence of an abnormal vessel originating from the distal ascending aorta proximal to the innominate artery. The distal connection and underlying cardiac or great vessel anomaly define the varied clinical presentations of this condition.

Reverse End-to-Side Neurotization in a Regenerating Nerve

Bypass grafting around a neuroma-in-continuity entails coapting a nerve graft above and below the injured segment using two sequential end-to-side repairs. The proximal repair is analogous to what has been classically described as an end-to-side repair; the axons from the intact nerve sprout into the end of a recipient nerve and travel distally. At the distal connection, however, axons in the graft must enter the side of the intact nerve and find their way to appropriate end organs. This process has not been well investigated. To examine this, a reverse end-to-side repair, suturing the distal end of the peroneal nerve to the side of a transected and repaired tibial nerve, was performed in 20 rats. A primary end-to-end repair of the tibial nerve was performed in 10 additional rats. Twelve weeks later, contraction forces of the gastrocnemius muscle were measured following proximal stimulation. Measurements were repeated following elimination of potential axonal pathways to identify which axons (peroneal or tibial) had achieved greater reinnervation. The results indicated that both groups of axons had achieved significant reinnervation. This study supports the idea that a reverse end-to-side repair can result in axonal invasion of an intact but regenerating nerve and achieve functional recovery.

Does the Site of Insertion of a Systemic-Pulmonary Shunt Influence Growth of the Pulmonary Arteries?

The modified Blalock-Taussig shunt is a common palliative procedure for children with cyanotic congenital heart disease. The distal shunt anastomosis can be done to a branch pulmonary artery or to the main pulmonary artery. The purpose of this study was to determine if the site of shunt connection influences pulmonary artery growth. The records of 101 patients with a modified Blalock-Taussig shunt undergoing a subsequent cardiac catheterization between January 2000 and April 2002 were retrospectively reviewed. From the cineangiograms, the diameters of the right and left pulmonary arteries at their first branching and the diameter of the descending aorta at the diaphragm were measured. If the distal shunt anastomosis was to the right pulmonary artery and there was no antegrade pulmonary flow then the left pulmonary artery was significantly smaller than if the distal connection was to the main pulmonary artery (p = 0.009). Absence of antegrade pulmonary blood flow resulted in significantly smaller right and left pulmonary artery size in general (p < 0.001). No significant differences in pulmonary artery growth were found with respect to gender, anatomic subtype, proximal shunt site, use of cardiopulmonary bypass or size of shunt. By multiple regression analysis absence of antegrade flow and the presence of right-sided shunts were statistically significant predictors of smaller left pulmonary artery and size discrepancy between right and left pulmonary artery. These data suggest that in the absence of antegrade pulmonary blood flow, a modified Blalock-Taussig shunt to the main pulmonary artery may promote more uniform branch pulmonary artery growth.

Computerized Three-Dimensional Potential Mapping with a Multielectrode Basket Catheter Can be Useful for Pulmonary Vein Electrical Disconnection

Pulmonary vein (PV) isolation (PVI) has been recently proposed as an effective technique to cure atrial fibrillation (AF). The aim of this study was to investigate the efficacy of a novel technique utilizing a computerized three-dimensional mapping system (QMS2) with a multielectrode basket catheter (MBC) for PVI and to reveal the relation between the style of breakthrough and the network of the PV musculature. Sixty-five consecutive patients with frequent AF attacks underwent PV mapping with a 31-mm MBC, and a three-dimensional color animation of the potential map was constructed by the QMS2. The animation color schema was arranged to minimize the low-amplitude left atrial (LA) potentials and emphasize the high-amplitude PV potentials (PVPs). The longitudinal PVP map enabled us to recognize the true breakthroughs and reveal the network of the PV musculature. A total of 205 PVs (65 left superior PVs, 65 right superior PVs, 57 left inferior PVs and 18 right inferior PVs) were mapped and successful PVI was achieved in all PVs, except one that had no PVPs, with a mean radiofrequency duration of 7 +/- 5 minutes per PV. In about 90% of the PVs, a final radiofrequency application eliminated all the distal PVPs simultaneously because the PVI was performed at the appropriate LA-PV junction. A single segmental breakthrough was detected in 17 PVs, single broad breakthrough in 83 PVs, multiple separate breakthroughs with a distal connection between the PV musculatures extending from each separate breakthrough in 88 PVs and multiple separate breakthroughs without that connection in 16 PVs. During the follow-up period, fifty-one (78%) patients were free of symptomatic AF without any antiarrhythmic drugs after multiple procedures (thirty-three (51%) of those patients after the first procedure) and no PV stenosis was found. Computerized three-dimensional potential mapping can be useful for PVI because it can not only identify the true breakthrough, but can also confirm the elimination of the breakthroughs by the change in the activation sequence through the network of the PV musculature.

Distally based first web flap for coverage reconstruction of the great toe

Resurfacing the distal part of the foot is still difficult. Distally based fascio-cutaneous first web flap has a sufficient arc of rotation to reach the toes. This flap is reverse-flow vascularised by the distal communicating artery, which is the distal connection between the plantar and the dorsal first metatarsal arteries. The authors describe its application for the coverage of a dorsal defect of the great toe.

Reconstruction of high ulnar nerve lesions by distal double median to ulnar nerve transfer.

Ulnar nerve lesions around the elbow often carry an unfavorable prognosis due to insufficient sensory and intrinsic muscle recovery. We present a series of 7 cases in which restoration of ulnar innervated intrinsic muscles of the hand and of skin sensibility was achieved. This was accomplished by a distal connection of the anterior interosseous nerve and the superficial sensory palmar branch of the median nerve to the motor and sensory components of the ulnar nerve at Guyon's canal. The length of the follow-up period ranged from 1 to 3.5 years. Results were graded by the Highet-Zachary scale. Good motor and sensory recovery was obtained in 6 cases; only return of protective sensation occurred in the remaining case.

Regeneration through a long nerve graft used in the correction of facial palsy. A qualitative and quantitative study.

A surgical technique has been developed for the correction of established unilateral palsy in man. A long (20 cm or more) sural nerve graft is anastomosed to a facial nerve branch on the unaffected side and its distal end left lying free in the cheek of the affected side. After regeneration times of 5.5-14.5 months, the distal end of the graft is joined to a free (pectoralis minor) muscle graft. In due course the muscle graft contracts in unison with the unaffected side giving near normal symmetry to facial movements. In 30 cases (ages 6-52 years) qualitative and quantitative examination was made of the distal end of grafts taken at the time of joining the graft to the muscle. Total axon counts, myelinated plus non-myelinated, confirmed abundant regeneration when compared with total axons in the supplying facial nerve; myelinated fibres remained small (mean diameter 2.5 micrometers) over the range of regeneration times. Quantitation included non-myelinated axons because they probably have the potential to become myelinated once the nerve is functional. Numbers of regenerating axons were not correlated with age, nor with regeneration time. Lack of a distal connection did not appear to lead to secondary degeneration of the regenerated myelinated fibres. These were maintained in an 'immature' state for many months. This observation is of practical interest since it has been suggested that delayed connection to the distal target may have a deleterious effect on the outcome of the procedure.