Tunnel Volume Research Articles

Model Test Study on the Response of Two Different Shallow-Foundation Framed Buildings under Tunnel Volume Loss

In order to study the influence of tunnel volume loss on adjacent framed buildings with different shallow foundations, this paper carried out physical model experiments with two common types of footings (isolated and strip footings) under different working conditions based on the digital image correlation (DIC) technique. The main finding of the present paper is that the increase in formation loss rate will aggravate the deformation and damage of the structure, and the strip foundation shows stronger integrity and stability compared with the isolated foundation in this process. With the increase in the eccentricity of the frames with respect to the tunnel, the overall tilt and damage degree of structural elements increases first and then decreases for both foundations, reaching the maximum value with the eccentric distance of one multiple of the tunnel diameter. Interestingly, when the isolated footings are located directly above the tunnel, the damage in the inner panels is the most severe and gradually decreases with eccentricity, changing from a sagging mode to a hogging mode for the frame form. While the strip footings always maintain slight hogging, and the trend of the damage degree of panels is similar to that of elements, with the eccentric distance reaching two times the tunnel diameter, the strip foundation structure tends to be stable, while the isolated one still needs attention for its potential possibility of damage in panels. The research results have reference value for the impact assessment of adjacent shallow-foundation framed buildings in subway tunnel construction.

Effect of Particle Size Distributions (PSDs) on ground responses induced by tunnelling in dense coarse-grained soils: A DEM investigation

Tunnelling-induced ground responses in coarse-grained soils often exhibit complex behaviours such as soil arching and progressive ground instability. However, the effect of particle size distributions (PSDs) on ground responses in tunnelling remains largely unexplored. This study provides new insights into PSD’s effect on tunnelling ground response and the underlying mechanism based on granular skeleton quantification. The coarse-grained soils with 9 typical PSDs were modelled by the discrete element method (DEM) with varied granular skeleton structures. A representative volume element (RVE) assembly method, with a novel iteration-based specimen generation method, is developed to build ground models incorporating millions of soil grains, where an eccentric displacement boundary was embedded for reproducing the tunnel volume losses. The results demonstrated that the change in skeleton structures from fine-grains to coarse-grains dominated leads to the acceleration of soil arch emergence and the deceleration of soil arch collapse-rebuilding. With an increase in ded, the strengthened soil arch leads to a more evident deformation localization in ground, and results in more significant hysteresis of ground instability from the tunnel to the surface. The effect of PSDs on ground responses becomes prominent as the overburden thickness decreases and the tunnel volume loss increases, and a decrease in ded would increase the risk of overall failure in tunnelling.

Assessment of twin tunnelling induced settlement and load transfer mechanism of a single pile in dry sand

This study conducted both three-dimensional physical model tests and numerical back-analyses to examine the performance of a single pile subjected to twin tunnelling beneath the pile toe in dry sand. Moreover, numerical parametric analyses were carried out to assess the impact of working load level and tunnel volume loss on pile behaviour. The findings revealed that the first tunnelling induced a 1.9% dp (pile diameter) settlement in the pile when the pile toe was 0.5 D (tunnel diameter) above the twin tunnels, which had a 1.0% volume loss. The settlement was accompanied by an upward load transfer mechanism. The second tunnelling had a reduced impact and induced only 76% of the settlement caused by the first tunnelling. The study also showed that tunnelling-induced shearing behaviours weakened beneath the pile toe with a decrease in working load, resulting in reduced pile head settlement. Moreover, the computed pile settlement increased by 178% when the tunnel volume loss increased from 0.5% to 2%. The findings of this study offer valuable data for the validation and calibration of numerical models. In addition, the outcome from this study provides useful insights into the prediction of the pile-soil-tunnel interaction when subjected to twin tunnelling.

Flower Size as an Honest Signal in Royal Irises (Iris Section Oncocyclus, Iridaceae).

Flower traits, such as flower size or color changes, can act as honest signals indicating greater rewards such as nectar; however, nothing is known about shelter-rewarding systems. Large flowers of Royal irises offer overnight shelter as a reward to Eucera bees. A black patch might signal the entrance to the tunnel (shelter) and, together with the flower size, these might act as honest signals. We hypothesize that larger flowers and black patches indicate larger tunnels, and larger tunnels will increase pollinator visits, enhancing the plants' reproductive success. We measured seven species in a controlled environment and two species from three natural populations varying in flower size. Fruit and seed sets were assessed in these natural populations. We found a positive correlation between the flower, patch size, and tunnel volume, suggesting that the flowers and patch size act as honest signals, both under controlled conditions and in the wild. However, in natural populations, this positive relationship and its effect on fitness was population-specific. Flower size increased the fitness in YER I. petrana, and interactions between flower/patch size and tunnel size increased the fitness in YER and I. atropurpurea NET populations. This suggests that the honesty of the signal is positively selected in these two populations. This study supports the hypothesis that pollinator-mediated selection leads to the honest signaling of flower advertisement.

Tunnel widening after ACL reconstruction with different fixation techniques: aperture fixation with biodegradable interference screws versus all-inside technique with suspensory cortical buttons. 5-year data from a prospective randomized trial.

The aim of the present study was to examine tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR) using two different fixation methods: aperture fixation with biodegradable interference screws versus all-inside ACLR with suspensory cortical buttons. Tunnel widening was assessed using volumetric and diameter measurements on magnetic resonance imaging (MRI) scans directly after surgery, as well as 6months and 2 and 5years postoperatively. Clinical outcomes were assessed after 5years with instrumented tibial anteroposterior translation measurement (KT-1000), single-leg hop testing, and the IKDC, Lysholm, and Tegner activity scores. At the final follow-up, the study population consisted of 21 patients, 12 of whom underwent screw fixation and 9 of whom had button fixation. 3 patients with all-inside ACLR had sustained early repeat ruptures within 6 months after surgery and had to be excluded from the further analysis. With screw fixation, the tibial tunnel volume changed significantly more over time compared to all-inside button fixation, with a larger initial increase at 6months (from postoperative 2.9 ± 0.2 to 3.3 ± 0.2 cm3 at 6months versus 1.7 ± 0.1 to 1.9 ± 0.2 cm3) and a greater final decrease over 2-5years postoperatively (from 3.1 ± 0.2 to 1.9 ± 0.2 cm3 versus 1.8 ± 0.2 ± 0.1 to 1.3 ± 0.1 cm3) (P < 0.001). The femoral tunnel volume remained comparable between the two groups throughout the follow-up period, with an initial 1.6 ± 0.1 cm3 in both groups and 1.2 ± 0.1 vs. 1.3 ± 0.1 after 5years in the screw and button groups, respectively (P ≥ 0.314). The maximum tibial and femoral tunnel diameters were significantly larger with screw fixation at all four time points. Tibial diameters measured 11.1 ± 0.2, 12.3 ± 0.3, 12.3 ± 0.4, and 11.2 ± 0.4mm in the screw group versus 8.1 ± 0.3, 8.9 ± 0.3, 9.1 ± 0.4 and 8.2 ± 0.5mm in the button group (P < 0.001). Femoral diameters measured 8.6 ± 0.2, 10.5 ± 0.4, 10.2 ± 0.3, and 8.9 ± 0.3 versus 7.3 ± 0.3, 8.4 ± 0.4, 8.4 ± 0.3, 7.5 ± 0.3, respectively (P ≤ 0.007). Four patients (33%) in the screw group exceeded a diameter of 12mm on the tibial side after 5years versus none in the button group (not significant, P = 0.104). Tibial anteroposterior translation measurement with KT-1000 after 5years was 2.3 ± 2.4mm in the screw group versus 3.2 ± 3.5mm in the button group (not significant, P = 0.602). There were no significant differences between the groups in any of the other clinical outcomes. Tibial tunnels in ACLR with screw fixation were associated with a larger increase in tunnel volume within the first 2years and a greater decrease up to 5years after surgery, while femoral tunnel volumes did not differ significantly. On the tibial side, the need for staged revision ACLR may be greater after biodegradable interference screw fixation if repeat ruptures occur, especially within the first 2years after primary ACLR. Concerns may remain regarding a higher graft failure rate with all-inside ACLR. II. NCT01755819.

An analytical investigation of soil arching induced by tunneling in sandy ground

The soil mass above the tunnel generally yields due to the tunnel volume loss. Depending on the amount of the volume loss, soil unit weight, overburden height and internal friction angle, a stress arching zone and a loosened zone can be formed above the tunnel. In this study, a two-dimensional stress field resulting from the tunnel volume loss inside the soil mass above the tunnel is investigated analytically. By presenting an analytical solution in rectangular coordinates, new equations were developed to evaluate and estimate the magnitude of vertical, horizontal and shear stress components inside the soil mass. The vertical stress changes resulting from the tunnel volume loss were analyzed and the height of the arching zone and the loosened zone above the tunnel were determined. In addition, a parametric study was conducted to evaluate the effect of soil unit weight, soil internal friction angle, surcharge on the ground surface and overburden depth on the stress distribution in the soil above the tunnel. The results showed that depending on the depth of the tunnel and the strength of the surrounding soil, the arching and loosened zones may or may not be created. In order to validate the proposed solution, the vertical stress distribution along the tunnel crest has been compared with some experimental and numerical data. It can be stated that the proposed solution provides relatively good approximations for the vertical stress component. The results of this research show that a safe and economical support system for tunnels in sandy ground can be designed using the proposed solution.

Osteoconductive Scaffold Placed at the Femoral Tunnel Aperture in Hamstring Tendon ACL Reconstruction: A Randomized Controlled Trial.

Bone tunnel enlargement after single-bundle anterior cruciate ligament reconstruction remains an unsolved problem that complicates revision surgery. Positioning of an osteoconductive scaffold at the femoral tunnel aperture improves graft-to-bone incorporation and thereby decreases bone tunnel widening. Randomized controlled trial; Level of evidence, 1. In a 1:1 ratio, 56 patients undergoing primary anterior cruciate ligament reconstruction were randomized to receive femoral fixation with cortical suspension fixation and secondary press-fit fixation at the tunnel aperture of the tendon graft only (control) or with augmentation by an osteoconductive scaffold (intervention). Adverse events, patient-reported outcomes, and passive knee stability were recorded over 2 years after the index surgery. Three-dimensional bone tunnel widening was assessed using computed tomography at the time of surgery and 4.5 months and 1 year postoperatively. The intervention group exhibited a similar number of adverse events as the control group (8 vs 10; P = .775) including 2 partial reruptures in both groups. The approach was feasible, although 1 case was encountered where the osteoconductive scaffold was malpositioned without adversely affecting the patient's recovery. There was no difference between the intervention and control groups in femoral bone tunnel enlargement, as expressed by the relative change in tunnel volume from surgery to 4.5 months (mean ± SD, 36% ± 25% vs 40% ± 25%; P = .644) and 1 year (19% ± 20% vs 17% ± 25%; P =.698). Press-fit graft fixation with an osteoconductive scaffold positioned at the femoral tunnel aperture is safe but does not decrease femoral bone tunnel enlargement at postoperative 1 year. NCT03462823 (ClinicalTrials.gov identifier).

Predictions of ground surface settlement for shield tunnels in sandy cobble stratum based on stochastic medium theory and empirical formulas

This paper focuses on the prediction of ground surface settlement induced by shield tunnelling in sandy cobble stratum. Based on the stochastic medium theory, an analytical solution to predict the surface settlement is developed considering the difference between soil and tunnel volume loss. Then, the effects of tunnel geometries, influence angle and volume loss on the characteristics of surface settlement are discussed. Through back analysis, a total of 103 groups of field monitoring data of surface settlement induced by shield tunnelling in sandy cobble stratum are examined to investigate the statistical characteristics of the maximum settlement, settlement trough width and volume loss. An empirical prediction is presented based on the results of back analysis. Finally, the analytical solution and empirical expression are validated by the comparisons with the results of model tests and field monitoring. Results show that the soil at ground surface has an overall dilative response for most of the shield tunnelling in sandy cobble stratum. In addition, the developed analytical solution is applicable and reasonable for surface settlement prediction. Meanwhile, the proposed empirical formula also shows good performance in some cases, providing an approach or a reference for engineering designers to preliminarily evaluate the surface settlement.

Morphological Changes in the Tibial Tunnel After ACL Reconstruction With the Outside-In Technique and Adjustable Suspensory Fixation.

Anterior cruciate ligament reconstruction (ACLR) using the complete tibial tunnel technique and adjustable-loop cortical suspensory fixation is known to leave a "dead space" that holds the loop device in the tibial tunnel. The consequence of the dead space and its effect on graft healing are still uncertain. To investigate morphological changes in the tibial tunnel and their effect on graft healing, and to identify factors affecting bone healing in the tibial loop tunnel after ACLR with a quadrupled semitendinosus tendon autograft using adjustable suspensory fixation. Case series; Level of evidence, 4. Included were 48 patients (34 male, 14 female; mean age, 25.2 ± 5.6 years) who underwent ACLR with a quadrupled semitendinosus tendon autograft using adjustable suspensory fixation. To evaluate tibial tunnel morphology, computed tomography was performed at 1 day and 6 months postoperatively. At 1 year postoperatively, graft healing was assessed on magnetic resonance imaging using the graft signal-to-noise quotient (SNQ). Multivariate regression and correlation analyses were performed to determine any associations between volumetric changes in bone healing and operative variables. At 6 months after ACLR, a mean of 63.2% of the tibial loop tunnel was filled by bone. Multivariate regression analysis showed that remnant preservation was significantly associated with the loop tunnel filling rate (P < .001). At 1 year after ACLR, the tibial loop tunnel was almost completely closed (98.5%). There were no correlations between loop tunnel volume and graft integration or graft SNQ. A significant but weak correlation was found between graft tunnel volume and intratunnel graft SNQ (P = .10) as well as integration grade in the tibial tunnel (P = .30). Excellent bone filling in the tibial loop tunnel was seen at 1 year after ACLR. Remnant preservation was significantly associated with the loop tunnel filling rate. A weak correlation was found between graft tunnel volume and intratunnel graft SNQ as well as integration grade in the tibial tunnel.

Carpal Tunnel Volume after Basal Joint Arthroplasty in Postmenopausal Women.

Background: Carpal tunnel syndrome is occasionally associated with basal joint arthritis and is more common in postmenopausal women than in the general population. Currently, more evidence is needed to describe changes in the carpal tunnel after basal joint arthroplasty (BJA) of the thumb and to determine whether it is better to combine the release of the flexor retinaculum. The purpose of this study was to clarify the changes in the carpal tunnel cross-sectional area and carpal tunnel shape after complete removal of the trapezium during BJA of the thumb, according to computed tomography (CT) findings. Methods: We retrospectively investigated the carpal tunnel cross-sectional area with CT findings obtained pre- and postoperatively in 20 postmenopausal women who underwent BJA of the thumb. Results: The average horizontal plane area of the carpal tunnel was 1.11 ± 0.19 cm2 preoperatively and increased to 1.23 ± 0.2 cm2 at 3 months postoperatively (p = 0.0411). The ratio of the longitudinal diameter to the horizontal diameter was significantly increased from 0.6 ± 0.13 preoperatively to 1.23 ± 0.2 postoperatively (p = 0.0439). Conclusions: The increase in the carpal tunnel cross-sectional area was confirmed after BJA of the thumb. This increased carpal tunnel cross-sectional area changed as the longitudinal diameter increased, without changes in the horizontal diameter. Level of Evidence: Level IV (Therapeutic).

Carpal tunnel volume distribution and morphology changes with flexion-extension and radial-ulnar deviation wrist postures.

Non-neutral wrist postures have been reported to cause decreased carpal tunnel volume (CTV) contributing to impingement of the median nerve and development of carpal tunnel syndrome. Recent analysis found CTV did not change with ±20° flexion-extension (FE), however, CTV decreased with ulnar deviation over the range of -5° to 15° radial-ulnar deviation (RUD). These findings suggest CTV may be too coarse of a measure to reflect the effects of slight non-neutral postures, or that volume is conserved and redistributed due to changes in tunnel morphology with posture. The objective of this study was to assess volume distribution along the length of the carpal tunnel and to quantify regional morphology changes with deviated wrist postures in both FE and RUD. Analysis was performed on a dataset of computed tomography scans collected on ten cadaveric specimens (5 male, 5 female, mean age = 80.7 ± 10.9 years) over a range of FE and RUD postures. The carpal tunnel of each scan was divided into four quartiles of equal length along the tunnel to quantify volume distribution. Volume within the carpal tunnel was seen to redistribute with both FE and RUD. Decreased volume in the distal aspect of the tunnel with flexion and proximal aspect of the tunnel with ulnar deviation may contribute to localized compression of the medial nerve. Measures of mean cross-sectional area, width and depth by quartile provided an indication of the morphology changes associated volume redistribution. Morphology analysis also revealed twisting between the proximal and distal aspects of the tunnel which increased with flexion and ulnar deviation and may further contribute to strain on the median nerve.

Experimental Investigation on the Effect of Volume Loss on Ground Movements Induced by Tunnelling in Sand

Complex ground conditions or support failures during tunnel construction can lead to high ground loss, which may cause damage to surrounding structures. In this paper, a series model tests are carried out in order to clarify tunnelling-induced ground deformation at high ground loss conditions. The model tunnel in this test is shallowly buried in loose sand and the tunnel volume loss (Vl,t) is set from 4% to 10%. The Vl,t is controlled by a water-filling-drainage system and the ground deformation is monitored by digital image correlation (DIC) system. The results show that the Peck-Gaussian function can be used to fit the settlement data well, and the increase of Vl,t has no significant effect on the width of the settlement trough, while the horizontal displacement can be described by modified empirical method. The width of influence aera caused by tunnelling decreases linearly with depth, and the width near the tunnel crown is about 78% of that on the surface. For loose sand ground, it is the shear band rather than the soil arch that dominates the ground deformation. Furthermore, excavation leads to a volume contraction of the ground, which suggests predictions based on tunnel over-excavation trend to underestimate the ground deformation, and that should be taken seriously in consideration of the safety of the engineering project. This study can provide a better understanding of ground deformation induced by tunnelling.

Quantifying wood decomposition by insects and fungi using computed tomography scanning and machine learning

Wood decomposition is a central process contributing to global carbon and nutrient cycling. Quantifying the role of the major biotic agents of wood decomposition, i.e. insects and fungi, is thus important for a better understanding of this process. Methods to quantify wood decomposition, such as dry mass loss, suffer from several shortcomings, such as destructive sampling or subsampling. We developed and tested a new approach based on computed tomography (CT) scanning and semi-automatic image analysis of logs from a field experiment with manipulated beetle communities. We quantified the volume of beetle tunnels in wood and bark and the relative wood volume showing signs of fungal decay and compared both measures to classic approaches. The volume of beetle tunnels was correlated with dry mass loss and clearly reflected the differences between beetle functional groups. Fungal decay was identified with high accuracy and strongly correlated with ergosterol content. Our data show that this is a powerful approach to quantify wood decomposition by insects and fungi. In contrast to other methods, it is non-destructive, covers entire deadwood objects and provides spatially explicit information opening a wide range of research options. For the development of general models, we urge researchers to publish training data.

High speed visual insect swarm tracker (Hi-VISTA) used to identify the effects of confinement on individual insect flight

Individual insects flying in crowded assemblies perform complex aerial maneuvers by sensing and feeding back neighbor measurements to small changes in their wing motions. To understand the individual feedback rules that permit these fast, adaptive behaviors in group flight, both experimental preparations inducing crowded flight and high-speed tracking systems capable of tracking both body motions and more subtle wing motion changes for multiple insects in simultaneous flight are needed. This measurement capability extends tracking beyond the previous focus on individual insects to multiple insects. This paper describes an experimental preparation that induces crowded insect flight in more naturalistic conditions (a laboratory-outdoor transition tunnel) and directly compares the resulting flight performance to traditional flight enclosures. Measurements are made possible via the introduction of a multi-agent high speed insect tracker called Hi-VISTA, which provides a capability to track wing and body motions of multiple insects using high speed cameras (9000–12 500 fps). Processing steps consist of automatic background identification, data association, hull reconstruction, segmentation, and feature measurement. To improve the biological relevance of laboratory experiments and develop a platform for interaction studies, this paper applies the Hi-VISTA measurement system to Apis mellifera foragers habituated to transit flights through the transparent transition environment. Binary statistical analysis (Welch’s t-test, Cohen’s d effect size) of 95 flight trajectories is presented, quantifying the differences between flights in an unobstructed environment and in a confined tunnel volume. The results indicate that body pitch angle, heading rate, flapping frequency, and vertical speed (heave) are each affected by confinement, and other flight variables show minor or statistically insignificant changes. These results form a baseline as swarm tracking and analysis begins to isolate the effects of neighbors from environmental enclosures, and improve the connection of high speed insect laboratory experiments to outdoor field experiments.

Serial magnetic resonance imaging evaluation of the early reaction of all-suture anchors in arthroscopic rotator cuff repair.

The aim of this study was to evaluate the early reaction of all-suture anchors (ASAs) in arthroscopic rotator cuff repair. This retrospective case series comprised 23 patients (8 women, 15 men; mean age = 59.9 years, age range = 36-73 years) with medium-size rotator cuff tear who underwent arthroscopic rotator cuff repair. All patients underwent postoperative serial magnetic resonance imaging (MRI) evaluation 3 and 6 months postoperatively. Demographic and operative characteristics were recorded. MRIs were evaluated for osseous cyst formation, and tunnel volume was measured. Statistical analyses were performed to detect differences in the serial MRI follow-up observation. A total of 39 ASAs were evaluated. Osseous cyst formation was found in two ASAs (5.1%) at the 6-month follow-up. Tunnel expansion was significantly observed in both 3- and 6-month postoperative MRI evaluations (P < 0.001). The mean tunnel volume significantly increased 1.95 times at the 3-month follow-up and 2.84 times at the 6-month follow-up (P < 0.001). Evidence from this study has revealed low rates of cyst formation but significant increases in tunnel volume at the early follow-up following arthroscopic rotator cuff repair with ASAs. Level IV, Therapeutic Study.

Effects of the skew angle of new tunneling on an existing tunnel: three-dimensional centrifuge and numerical modeling

Tunneling results in stress relief and arching in the ground. New tunnel excavation beneath an existing tunnel but at different angles can lead to different patterns of stress redistribution. Studies on multitunnel interaction have mainly focused on perpendicular tunnels, and the effects of tunneling skew angle remain poorly understood. Three-dimensional centrifuge modeling and numerical back-analyses were conducted to investigate the effects of twin-tunnel interaction at three skew angles (30°, 60°, and 90°). The effects of new tunnel excavation on an existing tunnel were simulated by controlling tunnel volume and weight losses in-flight. A hypoplastic soil model capable of simulating path-dependent and strain-dependent soil stiffness was adopted for the numerical back-analyses. Distinct load redistribution patterns were identified to explain deformations of the existing tunnel at different skew angles due to the advancement of the new tunnel. For 90° tunneling, hoop force increased at the crown and decreased at the left springline of the existing tunnel. The opposite responses were identified at 30° tunneling. A critical skew angle of 30° tunneling led to the maximum invert settlement and tunnel deformation of the existing tunnel. At 30° tunneling, the induced strain in the tunnel lining was 2.3 times larger than that of tunneling at 90°, exceeding the cracking limit suggested by the American Concrete Institute.

3D volumetric evaluation of the diagnosis and severity of carpal tunnel syndrome using MRI

BackgroundCarpal tunnel syndrome (CTS) is the most common nerve compression syndrome. The usage of clinical tests and nerve conduction studies (NCS), as well as ultrasonography and magnetic resonance images (MRI), have recently become widespread to diagnose CTS. This study aims to determine the alteration of the carpal tunnel volume based on disease seriousness by MIMICS 19.0 which is a three-dimensional modeling software. Materials and methodIn this study, 80 wrists of 63 (47 female and 16 male) patients with MRI and NCS results among 1252 patients who applied to our hospital with wrist pain and neuropathic complaints between January 2019 and August 2020 were included in our study. The patients were classified into four groups according to their NCS results as normal, mild CTS, moderate CTS, and severe CTS. Carpal tunnel volumes of the groups were measured with MIMICS 19.0 program using MRI. Three-dimensional carpal tunnel volume averages were statistically compared between the groups. Then, all statistical analyzes were performed using SPSS (Statistical Package for Social Sciences, version 23) software. ResultsThe results demonstrate the mean carpal tunnel volume values for normal, mild CTS, moderate CTS, and severe CTS are 5.51 cm3 ± 0.20, 5.27 cm3 ± 0.16, 4.86 cm3 ± 0.20, and 4.43 cm3 ± 0.24, respectively. Carpal tunnel volumes were found to be lower in all groups which have CTS compared to the normal group. As the groups with CTS were compared among themselves, a significant difference was found between the groups in terms of carpal tunnel volumes (p < 0.001). ConclusionsIn this study, a significant relationship between 3-dimensional measurements of carpal tunnel volume and the severity of CTS was observed. Therefore, MRI is an applicable method to diagnose and determine the severity of CTS.

Effects of slight flexion-extension and radial-ulnar deviation postures on carpal tunnel volume

BackgroundNon-neutral wrist postures are a commonly reported risk factor for carpal tunnel syndrome. It is unclear how slight flexion-extension and radial-ulnar deviation postures affect the carpal tunnel. The objective was to determine the effects of slight non-neutral postures by quantifying carpal tunnel volume. MethodsComputed tomography images were collected on ten cadaveric specimens in target postures of −20°, −10°, −5°, 0°, 5°, 10°, and 20° of flexion and − 10°, −5°, 0°, 5°, and 10° of radial-ulnar deviation. Surface meshes of the carpal tunnel, carpal bones, radius, and third metacarpal were generated with manual segmentation. Carpal tunnel volume was calculated as the volume between proximal and distal boundaries defined with anatomical landmarks and the orientation of the tunnel. The precise wrist posture of each scan was determined with inertial-based coordinate systems of the radius and third metacarpal. FindingsThrough multiple linear regression it was determined that, over the observed range of postures, flexion-extension angle does not have a significant effect (p = 0.99) while radial-ulnar deviation angle has a significant effect of −5.9 mm3/degree (p = 0.003). The findings were consistent with previous studies of postural effects on carpal tunnel pressure. InterpretationFor the treatment and prevention of carpal tunnel syndrome, results suggest that attention should be given to slight radial-ulnar deviation postures (<10°), while slight flexion-extension postures (<20°) are of lesser consequence to carpal tunnel volume.

Tarsal Tunnel Syndrome Following Medializing Calcaneal Osteotomy

Category:HindfootIntroduction/Purpose:The tarsal tunnel syndrome is a compressive neuropathy that affects either the posterior tibial nerve, within the tarsal tunnel, or one of its terminal branches. It can be caused by extrinsic or intrinsic factors. Even though the tarsal tunnel syndrome has been reported as a complication of lateralizing calcaneal osteotomy, we have not identified in the literature reports of this syndrome associated to medializing calcaneal osteotomy. We report the case of a 60-year-old female who developed a tarsal tunnel syndrome, on the third postoperative week, following a medializing calcaneal osteotomy for flatfoot correction with stage IIB posterior tibial tendon dysfunction.Methods:We reviewed and obtained the information from the medical records of this patient: clinical examination, radiographs, computed tomography, magnetic resonance imaging, and outcome. Pain was assessed with visual analog scale (VAS).Results:The patient is a 60-year-old female with left stage II posterior tibial tendon dysfunction who failed to respond to conservative treatment. Medializing and lengthening (Evans) osteotomies of the calcaneus were performed, together with posterior tibial tendon repair and spring ligament reconstruction. In the postoperative, after a cast replacement into a more plantigrade position, the patient developed symptoms that suggested a compressive neuropathy of posterior tibial nerve within the tarsal tunnel associated to calcaneal medializing osteotomy. Initial conservative treatment failed and the posterior tibial nerve was explored under loupe magnification and the tarsal tunnel was released. Figure 1. An immediate improvement in pain was observed postoperatively and almost full recovery occurred within 6 months.Conclusion:In our case report, the tarsal tunnel syndrome was a consequence of the osteotomy fragment displacement that generated a reduction of the tarsal tunnel volume. It has been described that the tarsal tunnel syndrome symptoms become more evident with ankle dorsiflexion and eversion, in our patient this can be associated with the symptom exacerbation presented when the cast was placed into plantigrade position. We conclude that even though in the literature the tarsal tunnel syndrome has been mainly associated to lateralizing osteotomies, it is important to take this complication into account when performing a medializing osteotomy.

Stereological and comparative evaluation of the carpal tunnel in patients with carpal tunnel syndrome using magnetic resonance images

Introduction: In this study, the relation between carpal tunnel syndrome (CTS) severity and the carpal tunnel volume (CTV), volume and the volume fraction of the carpal tunnel contents on subjects with CTS and healthy individuals were examined. Material and Methods: 30 female patients diagnosed with CTS clinically and electrophysiologically and 16 healthy female patients were included in this study. In patient group, 50 and in control group 30 hand wrists were examined. CTS severity was ranked electrophysiologically. T1-weighted axial magnetic resonance images (MRIs) were examined by the Cavalieri principle. Results: CTV in the patient group (4.26 ± 0.57 cm3) was found to be lower than that of the control group (4.66 ± 0.73 cm3), while the volume (0.41 ± 0.07 cm3) of the median nerve (Vnm) in the patient group was found to be higher than the control group (P < 0.05). Besides, the volume and volume fraction of the median nerve increase when the CTS severity increases (r = 0.610; r = 0.778). Discussion and Conclusion: Our study has shown that stereological studies with MRI are successful in determining the CTV in differentiating patients and healthy people. In addition, the volume and volume fraction of the median nerve were found to be quite effective in differentiating the severity of CTS. It is anatomically confirmed that when the severity of CTS increases, the space volume fraction of the carpal tunnel decreases.