The mechanical properties of biological soft tissues play a critical role in the study of biomechanics and the development of protective measures against human injury.Various testing techniques at different scales hav...The mechanical properties of biological soft tissues play a critical role in the study of biomechanics and the development of protective measures against human injury.Various testing techniques at different scales have been employed to characterize the mechanical behavior of soft tissues,which is essential for developing accurate tissue simulants and numerical models.This review comprehensively explores the mechanical properties of soft tissues,examining experimental methods,mechanical models,numerical simulations,and the progress in materials that mimic the mechanical performance of soft tissues.Finally,it reviews the damage and protection of human tissues under kinetic impacts,anticipating the future construction of soft tissue surrogate targets.The aim is to provide a systematic theoretical foundation and the latest advancements in the field,addressing the design,preparation,and quantitative modeling of biomimetic materials,thereby promoting the in-depth development of soft tissue mechanics and its applications.展开更多
In endoscopic surgery,the limited field of view and the nonlinear deformation of organs caused by patient movement and respiration significantly complicate the modeling and accurate tracking of soft tissue surfaces fr...In endoscopic surgery,the limited field of view and the nonlinear deformation of organs caused by patient movement and respiration significantly complicate the modeling and accurate tracking of soft tissue surfaces from endoscopic image sequences.To address these challenges,we propose a novel Hybrid Triangular Matching(HTM)modeling framework for soft tissue feature tracking.Specifically,HTM constructs a geometric model of the detected blobs on the soft tissue surface by applying the Watershed algorithm for blob detection and integrating the Delaunay triangulation with a newly designed triangle search segmentation algorithm.By leveraging barycentric coordinate theory,HTMrapidly and accurately establishes inter-frame correspondences within the triangulated model,enabling stable feature tracking without explicit markers or extensive training data.Experimental results on endoscopic sequences demonstrate that this model-based tracking approach achieves lower computational complexity,maintains robustness against tissue deformation,and provides a scalable geometric modeling method for real-time soft tissue tracking in surgical computer vision.展开更多
During restorative dental procedures,complete control over the operative site is critical for patient comfort,safety,and the operator’s access and visibility.The success of a fixed prosthesis depends on accurate impr...During restorative dental procedures,complete control over the operative site is critical for patient comfort,safety,and the operator’s access and visibility.The success of a fixed prosthesis depends on accurate impression making of the prepared finish lines on the abutment teeth.To optimise long-term outcomes for the fixed restoration,gingival retraction techniques should be used to decrease the marginal discrepancy among the restoration and the prepared abutment.Accurate marginal positioning of the restoration along the prepared finish line of the abutment is essential for therapeutic,preventive,and aesthetic purposes.展开更多
BACKGROUND Osteoporotic vertebral fracture(OVF)is one of the most common sequelae of osteoporosis.Differential diagnosis between OVF and malignant vertebral fracture(MVF)is a challenge in clinical practice.Findings on...BACKGROUND Osteoporotic vertebral fracture(OVF)is one of the most common sequelae of osteoporosis.Differential diagnosis between OVF and malignant vertebral fracture(MVF)is a challenge in clinical practice.Findings on computed tomography and magnetic resonance images(MRI)may help to differentiate between these two types of fracture.AIM To determine whether paravertebral soft tissue swelling is useful for differentiation between OVF and MVF.METHODS We retrospectively reviewed the MRI for 165 patients diagnosed with a vertebral fracture between May 2021 and July 2022.Three radiologists evaluated the vertebral segments and thickness of soft tissue swelling on sagittal MRI by consensus.The morphology of the soft tissue swelling was also evaluated.The statistical analyses were performed using theχ^(2) test and analysis of variance.RESULTS The study included 117 patients(153 vertebrae)with OVF and 48 patients(63 vertebrae)with MVF.Soft tissue swelling was observed beneath the anterior longitudinal ligament on sagittal MRI and rim-shaped in the paravertebral area on axial MRI in all 153 vertebrae with OVF(100%)and in 12(19%)of the 63 vertebra with MVF;the difference was statistically significant(P<0.001),95%CI:3.156–8.735.Soft tissue swelling beneath the anterior longitudinal ligament spanned significantly more vertebral segments in patients with OVF than in those with MVF(P<0.001),95%CI:0.932-1.546.The mean thickness of the soft tissue swelling was significantly greater for OVF than for MVF(5.62 mm±2.50 mm vs 3.88 mm±1.73 mm,P<0.05,95%CI:0.681–0.920).Post-contrast examination was performed in 13 patients;T1-weighted images confirmed OVF in 11 cases and MVF in 2 cases.Soft tissue swelling in OVF and MVF had a fusiform appearance or appeared as a thin line on sagittal MRI and was rim-shaped on axial MRI.The length and diameter of the soft tissue swelling in patients with OVF decreased during follow-up.CONCLUSION Paravertebral soft tissue swelling is helpful for differentiating between OVF and MVF.展开更多
INTRODUCTION Benign metastasising leiomyoma (BML) is a rare condition marked by well-differentiated smooth muscle tumours appearing outside the uterus in women with a history of uterine leiomyoma.Metastasis from leiom...INTRODUCTION Benign metastasising leiomyoma (BML) is a rare condition marked by well-differentiated smooth muscle tumours appearing outside the uterus in women with a history of uterine leiomyoma.Metastasis from leiomyoma is found to be most common in the lungs(79.5%),but other organs,including the heart,lymph nodes,spine and soft tissues,can also be affected.展开更多
Alveolar soft tissue sarcoma is a rare malignant tumor of soft tissue,more common in young women,with deep soft tissues in the limbs and buttocks being the most prevalent sites.There are few reported cases in clinical...Alveolar soft tissue sarcoma is a rare malignant tumor of soft tissue,more common in young women,with deep soft tissues in the limbs and buttocks being the most prevalent sites.There are few reported cases in clinical practice.The clinical manifestations lack specificity and the imaging signs are diverse.This case presents ultrasound,MRI and PET/CT images of alveolar soft tissue sarcoma of the gluteus maximus muscle to enhance readers’understanding and awareness of the imaging signs of this rare disease in order to raise awareness of its diagnosis.The characteristics of this case are summarized and reported in combination with domestic literature.展开更多
Soft tissue sarcomas(STS)are rare malignant tumors originating from mesoder-mal tissues with a poor prognosis,accounting for approximately 1%of all malig-nancies and comprising around 50 distinct subtypes.Conventional...Soft tissue sarcomas(STS)are rare malignant tumors originating from mesoder-mal tissues with a poor prognosis,accounting for approximately 1%of all malig-nancies and comprising around 50 distinct subtypes.Conventional imaging mo-dalities,such as computed tomography(CT)and magnetic resonance imaging(MRI),primarily provide anatomical information,whereas 18F-fluorodeoxyglucose positron emission tomography/CT(18F-FDG PET/CT)integrates functional metabolic and anatomical imaging,serving as a critical complementary tool in the diagnosis and management of STS.This article reviews recent advances in the application of 18F-FDG PET/CT for STS.The advantages of 18F-FDG PET/CT in STS include:(1)Early detection of metabolic activity changes in tumors,partic-ularly when morphological alterations are insignificant;(2)Effective differen-tiation between benign and malignant soft tissue tumors,as well as aiding in distinguishing high-grade from low-grade sarcomas;(3)Identification of occult metastatic lesions,improving staging accuracy,and facilitating restaging in cases of recurrence or metastasis;(4)Utilization of parameters such as maximum stan-dardized uptake value and metabolic tumor volume to assist in tumor grading and prognostic evaluation;and(5)Monitoring treatment response to guide adjust-ments in personalized therapeutic strategies.However,18F-FDG PET/CT has limitations in diagnosis of certain STS subtypes(e.g.,myxoid liposarcoma),detection and biopsy of metastatic lymph nodes,necessitating integration with clinical evaluation and other imaging techniques.18F-FDG PET/CT is poised to play an increasingly vital role in the precision diagnosis and treatment of STS.展开更多
Soft tissue sarcoma(STS)accounts for 1%of all malignant neoplasms in adults.Their diagnosis and management constitute a challenging target.They originate from the mesenchyme,and 50 subtypes with various cytogenetic pr...Soft tissue sarcoma(STS)accounts for 1%of all malignant neoplasms in adults.Their diagnosis and management constitute a challenging target.They originate from the mesenchyme,and 50 subtypes with various cytogenetic profiles concerning soft tissue and bones have been recognized.These tumors mainly affect middle-aged adults but may be present at any age.Half of the patients have metastatic disease at the time of diagnosis and require systemic therapy.Tumors above 3-5 cm in size must be suspected of potential malignancy.A thorough history,clinical examination and imaging that must precede biopsy are necessary.Modern imaging techniques include ultrasound,computed tomography(CT),new magnetic resonance imaging(MRI),and positron emission tomography/CT.MRI findings may distinguish low-grade from high-grade STS based on a diagnostic score(tumor heterogeneity,intratumoral and peritumoral enhancement).A score≥2 indicates a high-grade lesion,and a score≤1 indicates a lowgrade lesion.For disease staging,abdominal imaging is recommended to detect early abdominal or retroperitoneal metastases.Liquid biopsy by detecting genomic material in serum is a novel diagnostic tool.A preoperative biopsy is necessary for diagnosis,prognosis and optimal planning of surgical intervention.Core needle biopsy is the most indicative and effective.Its correct performance influences surgical management.An unsuccessful biopsy means the dissemination of cancer cells into healthy anatomical structures that ultimately affect resectability and survival.Complete therapeutic excision(R0)with an acceptable resection margin of 1 cm is the method of choice.However,near significant structures,i.e.,vessels,nerves,an R2 resection(macroscopic margin involvement)preserving functionality but having a risk of local recurrence can be an acceptable choice,after informing the patient,to prevent an unavoidable amputation.For borderline resectability of the tumor,neoadjuvant chemo/radiotherapy has a place.Likewise,after surgical excision,adjuvant therapy is indicated,but chemotherapy in nonmetastatic disease is still debatable.The five-year survival rate reaches up to 55%.Reresection is considered after positive or uncertain resection margins.Current strategies are based on novel chemotherapeutic agents,improved radiotherapy applications to limit local side effects and targeted biological therapy or immunotherapy,including vaccines.Young age is a risk factor for distant metastasis within 6 mo following primary tumor resection.Neoadjuvant radiotherapy lasting 5-6 wk and surgical resection are indicated for highgrade STS(grade 2 or 3).Wide surgical excision alone may be acceptable for patients older than 70 years.However,locally advanced disease requires a multidisciplinary task of decision-making for amputation or limb salvage.展开更多
Several problems about acupuncture and moxibustion for treatment of soft tissue injury are probed in the present paper. The author holds that for treatment of soft tissue injury with acupuncture and moxibustion, first...Several problems about acupuncture and moxibustion for treatment of soft tissue injury are probed in the present paper. The author holds that for treatment of soft tissue injury with acupuncture and moxibustion, firstly, must clarify the lesion location, so as to understand pathogenic characteristics and select the best acupuncture forcing point; secondly, must distinguish different stages of the disease, so as to select the best proper acupuncture stimulation method according to different pathological mechanisms in acute and chronic stages. Finally, the author analyzes different stimulation characteristics and indications according to own experience on clinical commonly-used several acupuncture and moxibustion stimulation methods such as filiform needle, acupoint injection, micro-needle therapy including ear acupuncture, abdomen acupuncture, eye acupuncture and so on, and blood-letting puncturing and cupping, fire needle and small needle-knife, and puts forward own treatment points of view.展开更多
BACKGROUND Diffuse large B-cell lymphoma(DLBCL)is the most common subtype of non�Hodgkin lymphoma,and patients with DLBCL typically present rapidly growing masses.Lymphoma involving muscle is rare and accounts for onl...BACKGROUND Diffuse large B-cell lymphoma(DLBCL)is the most common subtype of non�Hodgkin lymphoma,and patients with DLBCL typically present rapidly growing masses.Lymphoma involving muscle is rare and accounts for only 5%;furthermore,multiple muscles and soft tissue involvement of DLBCL is unusual.Due to unusual clinical manifestation,accurate diagnosis could be delayed.CASE SUMMARY A 61-year-old man complained of swelling,pain and erythematous changes in the lower abdomen.Initially,soft tissue infection was suspected,however,skin lesion did not respond to antibiotics.18Fluoro-2-deoxy-D-glucose(18F-FDG)positron emission tomography-computed tomography demonstrated FDG uptake not only in the skin and subcutaneous tissue of the abdomen but also in the abdominal wall muscles,peritoneum,perineum,penis and testis.DLBCL was confirmed by biopsy of the abdominal wall muscle and subcutaneous tissue.After intensive treatment including chemotherapy with rituximab,cyclophosphamide,doxorubicin,vincristine and prednisolone,central nervous system prophylaxis(intrathecal injection of methotrexate,cytarabine and hydrocortisone)and orchiectomy,he underwent peripheral blood stem cell mobilization for an autologous hematopoietic stem cell transplantation.Despite intensive treatment,the disease progressed rapidly and the patient showed poor outcome(overall survival,9 mo;disease free survival,3 mo).CONCLUSION The first clinical manifestation of soft tissue DLBCL involving multiple muscles was similar to the infection of the soft tissue.展开更多
Summary： In this study we present our experiences with the reverse sural fasciocutaneous flap to reconstruct the distal lower limb soft tissue defects caused by traumatic injuries. These flap graftings were carried o...Summary： In this study we present our experiences with the reverse sural fasciocutaneous flap to reconstruct the distal lower limb soft tissue defects caused by traumatic injuries. These flap graftings were carried out from Oct. 2010 to Dec. 2012 in our department. The series consisted of 36 patients, including 21 men and 15 women with an average age of 46.2 years （14-83 years） and with a medium followp period of 18 months （12-24 months）. Of all the cases of acute trauma, there were 10 eases of trauma of distal tibia, 9 cases of trauma of perimalleolus, and 17 cases of trauma of midfoot and forefoot. Related risk factors in the patients were diabetes （2 cases）, advanced age （〉65 years, 3 cases） and ciga- rette smoking （6 cases）. The reverse flow sural island flap irrigation depended on lower perforators of the peroneal artery. The fasciocutaneous pedicle was 3-4 cm in width and the anatomical structures consisted of the superficial and deep fascia, the sural nerve, short saphenous vein, superficial sural artery together with an islet of subcutaneous cellular tissue and skin. The most proximal border of the flap was only 1.5 cm away from the popliteal skin crease and the pivot point was 5-7 cm above the tip of the lateral malleolus. All the flaps survived. No arterial crisis occurred in any case. The venous congestion occurred in 2 cases and got better after raising the limbs and bloodletting. Only in an old man, 1.5 cm necrosis of distal margin of his flap occurred and finally healed after continuous dressing change. One-stage skin grafting was performed, and all the donor sites were sutured and successfully healed. It was concluded that the reverse sural fasciocutaneous flap is safe and reliable to extend to the proximal third even near the popliteal skin crease. We also concluded this flap can be safely and efficiently used to treat patients with large and far soft-tissue defects from the distal leg to the forefoot with more versatility and it is easier to reach the recipient sites.展开更多
Elasticity is of profound significance to evaluating the function of a biological soft tissue. When the elasticity of a tissue is macroscopically changed, it means that the biological function of the tissue is abnorma...Elasticity is of profound significance to evaluating the function of a biological soft tissue. When the elasticity of a tissue is macroscopically changed, it means that the biological function of the tissue is abnormal and some disease or injury may occur. In the present work, an elastometer is developed to measure the elasticity of biological soft tissues. The measurement is based on the indentation method and the force is measured by the bending of the cantilever. The force-indentation data of the soft tissue is experimentally measured by this elastometer and Young＇s modulus of the tissue is calculated using the Hertz-Sneddon model. For comparison, a numerical model for the indentation method is established using the finite element method. The difference between the actual modulus and the measured modulus is discussed. The effect of the thickness of the specimen on the measurement is investigated. Young＇s moduli of beef, porcine liver and porcine kidney are experimentally measured. The results indicate that our elastometer is effective in measuring Young＇s modulus of a soft tissue quantitatively.展开更多
Following dental implantation,the characteristic bacterial milieu of the oral cavity may lead to peri-implant inflammation,which can negatively impact osseointegration and cause implant failure.To improve soft tissue ...Following dental implantation,the characteristic bacterial milieu of the oral cavity may lead to peri-implant inflammation,which can negatively impact osseointegration and cause implant failure.To improve soft tissue sealing around the implant,enhance osseointegration,and improve implant success rates,this paper proposes a composite multifunctional coating(PHG)prepared using gelatin and polydopamine/hydroxyapatite nanoparticles,investigates the effects of this novel coating on cell adhesion,proliferation,antibacterial activity,osteogenic differentiation,and evaluates its immune-related properties.The PHG coating was proved to have satisfactory hydrophilicity and wettability for cell attachment.Furthermore,it improved the expression of adhesion-related genes and proteins in human gingival fibroblasts,indicating its adhesion-promoting effect.Additionally,bone marrow mesenchymal stem cells exhibited strong osteogenic differentiation potential and mineralization on PHG-coated surfaces.Notably,the PHG coating exhibited antibacterial activity against Streptococcus mutans,as well as anti-inflammatory effects,potentially via the regulation of macrophages.Therefore,the proposed PHG coating may promote soft tissue sealing and bone bonding,providing a potential strategy for the surface modification of dental implants.展开更多
In order to solve the problem of high computing cost and low simulation accuracy caused by discontinuity of incision in traditional meshless model,this paper proposes a soft tissue deformation model based on the Marqu...In order to solve the problem of high computing cost and low simulation accuracy caused by discontinuity of incision in traditional meshless model,this paper proposes a soft tissue deformation model based on the Marquardt algorithm and enrichment function.The model is based on the element-free Galerkin method,in which Kelvin viscoelastic model and adjustment function are integrated.Marquardt algorithm is applied to fit the relation between force and displacement caused by surface deformation,and the enrichment function is applied to deal with the discontinuity in the meshless method.To verify the validity of the model,the Sensable Phantom Omni force tactile interactive device is used to simulate the deformations of stomach and heart.Experimental results show that the proposed model improves the real-time performance and accuracy of soft tissue deformation simulation,which provides a new perspective for the application of the meshless method in virtual surgery.展开更多
BACKGROUND Clear cell sarcoma(CCS)is a rare and highly malignant soft tissue tumor,usually occurring in the deep soft tissues of the distal tendons and aponeurosis of the extremities,especially the feet and knees.CCS ...BACKGROUND Clear cell sarcoma(CCS)is a rare and highly malignant soft tissue tumor,usually occurring in the deep soft tissues of the distal tendons and aponeurosis of the extremities,especially the feet and knees.CCS originating in the head and neck is extremely rare.The clinical manifestations of CCS in the head and neck are not typical,and the imaging manifestations have certain characteristics,but the diagnosis still depends on pathological examination and genetic testing.CASE SUMMARY A 33-year-old male patient had paroxysmal headache for more than 4 years,accompanied by nausea and vomiting,which could be relieved after rest.Computed tomography angiography showed a left paraspinal soft tissue mass.Contrast-enhanced imaging showed obvious uneven enhancement with adjacent bone lytic destruction.Magnetic resonance imaging examination showed isosignal on T_(1)-weighted images,slightly high signal on T_(2)-weighted images(T_(2)WI),high signal on Tirm fat suppression sequence,significantly high signal on diffusion weighted imaging,and obvious and uneven enhancement.The lesion invaded the anterior medulla oblongata through the left atlantoaxial foramen and compressed the cervical spinal cord on T_(2)WI.Primary CCS of soft tissue was diagnosed by pathology and genetic examination.CONCLUSION CCS should be considered in the differential diagnosis of soft tissue tumors of the head and neck,and their diagnosis depends on pathological examination and genetic testing.展开更多
BACKGROUND Active myofascial trigger points(TrPs)often occur in the upper region of the upper trapezius(UT)muscle.These TrPs can be a significant source of neck,shoulder,and upper back pain and headaches.These TrPs an...BACKGROUND Active myofascial trigger points(TrPs)often occur in the upper region of the upper trapezius(UT)muscle.These TrPs can be a significant source of neck,shoulder,and upper back pain and headaches.These TrPs and their related pain and disability can adversely affect an individual’s everyday routine functioning,work-related productivity,and general quality of life.AIM To investigate the effects of instrument assisted soft tissue mobilization(IASTM)vs extracorporeal shock wave therapy(ESWT)on the TrPs of the UT muscle.METHODS A randomized,single-blind,comparative clinical study was conducted at the Medical Center of the Egyptian Railway Station in Cairo.Forty patients(28 females and 12 males),aged between 20-years-old and 40-years-old,with active myofascial TrPs in the UT muscle were randomly assigned to two equal groups(A and B).Group A received IASTM,while group B received ESWT.Each group was treated twice weekly for 2 weeks.Both groups received muscle energy technique for the UT muscle.Patients were evaluated twice(pre-and posttreatment)for pain intensity using the visual analogue scale and for pain pressure threshold(PPT)using a pressure algometer.RESULTS Comparing the pre-and post-treatment mean values for all variables for group A,there were significant differences in pain intensity for TrP1 and TrP2(P=0.0001)and PPT for TrP1(P=0.0002)and TrP2(P=0.0001).Also,for group B,there were significant differences between the pre-and post-treatment pain intensity for TrP1 and TrP2 and PPT for TrP1 and TrP2(P=0.0001).There were no significant differences between the two groups in the post-treatment mean values of pain intensity for TrP1(P=0.9)and TrP2(P=0.76)and PPT for TrP1(P=0.09)and for TrP2(P=0.91).CONCLUSION IASTM and ESWT are effective methods for improving pain and PPT in patients with UT muscle TrPs.There is no significant difference between either treatment method.展开更多
The force model during needle insertion into soft tissue is important for accurate percutaneous intervention.In this paper,a force model for needle insertion into a tissue- equivalent material is presented and a serie...The force model during needle insertion into soft tissue is important for accurate percutaneous intervention.In this paper,a force model for needle insertion into a tissue- equivalent material is presented and a series of experiments are conducted to acquire data from needle soft- tissue interaction process.In order to build a more accurate insertion force model,the interaction force between a surgical needle and soft tissue is divided into three parts:stiffness force,friction force,and cutting force.The stiffness force is modeled on the basis of contact mechanics model.The friction force model is presented using a modified Winkler' s foundation model.The cutting force is viewed as a constant depending on a given tissue.The proposed models in the paper are established on the basis of the mechanical properties and geometric parameters of the needle and soft tissue.The experimental results illustrate that the force models are capable of predicting the needle-tissue interaction force.The force models of needle insertion can provide real-time haptic feedback for robot-assisted procedures,thereby improving the accuracy and safety of surgery.展开更多
Objective: A pilot study to test the feasibility and efficacy of high dose IFO and standard dose ADR and DTIC with G-CSF support in treatment of advanced soft tissue sarcoma (STS). Methods: 35 patients of no prior che...Objective: A pilot study to test the feasibility and efficacy of high dose IFO and standard dose ADR and DTIC with G-CSF support in treatment of advanced soft tissue sarcoma (STS). Methods: 35 patients of no prior chemotherapy with metastatic or locally advanced unresectable STS were treated by this regimen, including 18 rhabdomyosarcomas, 7 malignant fibrous histiocytomas, 2 neurofibrosarcomas, 2 fibrosarcomas, 2 leiomyosarcomas, 2 synoviosarcomas, and 2 malignant hemangiopericytomas. IFO dose was 2 g/m2 on day 1–5 (with mesna uroprotection), ADR 50mg/m2 on day 1 and DTIC 250 mg/m2 on day 1–5. G-CSF (2 μg/kg/d) was administered on day 6 to 15 or until recovery of leukocytes account. The cycles were repeated every 3 weeks. Result: There were five complete responses (CR including pathologic CR) and eleven partial responses for overall 46% objective response rate. Most responses were observed within two cycles. The median survival was 15 months. Following CR, two patients remain disease free at 45 and 28 months, respectively. 6/120 (5%) cycles were complicated by grade IV neutropenia, 46/120 (38%) cycles had grade III neutropenia. No patients had treatment-related deaths. Nonhematologic toxicity consisted predominantly of anorexia and vomiting. No other severe toxicities were seen, especially no severe cardiotoxicity. Conclusion: This regimen is well tolerated and has substantial benefits for patients with advanced soft tissue sarcomas.展开更多
The simulation and planning system(SPS)requires accurate and real-time feedback regarding the deformation of soft tissues during the needle insertion procedure.Traditional mechanical-based models such as the finite el...The simulation and planning system(SPS)requires accurate and real-time feedback regarding the deformation of soft tissues during the needle insertion procedure.Traditional mechanical-based models such as the finite element method(FEM)are widely used to compute the deformations of soft tissue.However,it is difficult for the FEM or other methods to find a balance between an acceptable image fidelity and real-time deformation feedback due to their complex material properties,geometries and interaction mechanisms.In this paper,a Kriging-based method is applied to model the soft tissue deformation to strike a balance between the accuracy and efficiency of deformation feedback.Four combinations of regression and correlation functions are compared regarding their ability to predict the maximum deformations of ten characteristic markers at a fixed insertion depth.The results suggest that a first order regression function with Gaussian correlation functions can best fit the results of the ground truth.The functional response of the Kriging-based method is utilized to model the dynamic deformations of markers at a series of needle insertion depths.The feasibility of the method is verified by investigating the adaptation to step variations.Compared with the ground truth of the finite element(FE)results,the maximum residual is less than 0.92 mm in the Y direction and 0.31 mm in the X direction.The results suggest that the Kriging metamodel provides real-time deformation feedback for a target and an obstacle to a SPS.展开更多
Real-time performance and accuracy are two most challenging requirements in virtual surgery training.These difficulties limit the promotion of advanced models in virtual surgery,including many geometric and physical m...Real-time performance and accuracy are two most challenging requirements in virtual surgery training.These difficulties limit the promotion of advanced models in virtual surgery,including many geometric and physical models.This paper proposes a physical model of virtual soft tissue,which is a twist model based on the Kriging interpolation and membrane analogy.The proposed model can quickly locate spatial position through Kriging interpolation method and accurately compute the force change on the soft tissue through membrane analogy method.The virtual surgery simulation system is built with a PHANTOM OMNI haptic interaction device to simulate the torsion of virtual stomach and arm,and further verifies the real-time performance and simulation accuracy of the proposed model.The experimental results show that the proposed soft tissue model has high speed and accuracy,realistic deformation,and reliable haptic feedback.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U2241273)the Beijing Municipal Natural Science Foundation(Grant No.Z240017)+3 种基金the 111 project(Grant No.B13003)the Fundamental Research Funds for the Central Universitiesthe China Scholarship Councilthe Academic Excellence Foundation of BUAA for PhD Students.
文摘The mechanical properties of biological soft tissues play a critical role in the study of biomechanics and the development of protective measures against human injury.Various testing techniques at different scales have been employed to characterize the mechanical behavior of soft tissues,which is essential for developing accurate tissue simulants and numerical models.This review comprehensively explores the mechanical properties of soft tissues,examining experimental methods,mechanical models,numerical simulations,and the progress in materials that mimic the mechanical performance of soft tissues.Finally,it reviews the damage and protection of human tissues under kinetic impacts,anticipating the future construction of soft tissue surrogate targets.The aim is to provide a systematic theoretical foundation and the latest advancements in the field,addressing the design,preparation,and quantitative modeling of biomimetic materials,thereby promoting the in-depth development of soft tissue mechanics and its applications.
基金Support by Sichuan Science and Technology Program[2023YFSY0026,2023YFH0004].
文摘In endoscopic surgery,the limited field of view and the nonlinear deformation of organs caused by patient movement and respiration significantly complicate the modeling and accurate tracking of soft tissue surfaces from endoscopic image sequences.To address these challenges,we propose a novel Hybrid Triangular Matching(HTM)modeling framework for soft tissue feature tracking.Specifically,HTM constructs a geometric model of the detected blobs on the soft tissue surface by applying the Watershed algorithm for blob detection and integrating the Delaunay triangulation with a newly designed triangle search segmentation algorithm.By leveraging barycentric coordinate theory,HTMrapidly and accurately establishes inter-frame correspondences within the triangulated model,enabling stable feature tracking without explicit markers or extensive training data.Experimental results on endoscopic sequences demonstrate that this model-based tracking approach achieves lower computational complexity,maintains robustness against tissue deformation,and provides a scalable geometric modeling method for real-time soft tissue tracking in surgical computer vision.
文摘During restorative dental procedures,complete control over the operative site is critical for patient comfort,safety,and the operator’s access and visibility.The success of a fixed prosthesis depends on accurate impression making of the prepared finish lines on the abutment teeth.To optimise long-term outcomes for the fixed restoration,gingival retraction techniques should be used to decrease the marginal discrepancy among the restoration and the prepared abutment.Accurate marginal positioning of the restoration along the prepared finish line of the abutment is essential for therapeutic,preventive,and aesthetic purposes.
基金approved by the Institutional Review Board of the Affiliated hospital of Qingdao University(No.QYFYWZLL29413/dated 5rd September 2023),and all patient requirements for informed consent were waived.
文摘BACKGROUND Osteoporotic vertebral fracture(OVF)is one of the most common sequelae of osteoporosis.Differential diagnosis between OVF and malignant vertebral fracture(MVF)is a challenge in clinical practice.Findings on computed tomography and magnetic resonance images(MRI)may help to differentiate between these two types of fracture.AIM To determine whether paravertebral soft tissue swelling is useful for differentiation between OVF and MVF.METHODS We retrospectively reviewed the MRI for 165 patients diagnosed with a vertebral fracture between May 2021 and July 2022.Three radiologists evaluated the vertebral segments and thickness of soft tissue swelling on sagittal MRI by consensus.The morphology of the soft tissue swelling was also evaluated.The statistical analyses were performed using theχ^(2) test and analysis of variance.RESULTS The study included 117 patients(153 vertebrae)with OVF and 48 patients(63 vertebrae)with MVF.Soft tissue swelling was observed beneath the anterior longitudinal ligament on sagittal MRI and rim-shaped in the paravertebral area on axial MRI in all 153 vertebrae with OVF(100%)and in 12(19%)of the 63 vertebra with MVF;the difference was statistically significant(P<0.001),95%CI:3.156–8.735.Soft tissue swelling beneath the anterior longitudinal ligament spanned significantly more vertebral segments in patients with OVF than in those with MVF(P<0.001),95%CI:0.932-1.546.The mean thickness of the soft tissue swelling was significantly greater for OVF than for MVF(5.62 mm±2.50 mm vs 3.88 mm±1.73 mm,P<0.05,95%CI:0.681–0.920).Post-contrast examination was performed in 13 patients;T1-weighted images confirmed OVF in 11 cases and MVF in 2 cases.Soft tissue swelling in OVF and MVF had a fusiform appearance or appeared as a thin line on sagittal MRI and was rim-shaped on axial MRI.The length and diameter of the soft tissue swelling in patients with OVF decreased during follow-up.CONCLUSION Paravertebral soft tissue swelling is helpful for differentiating between OVF and MVF.
文摘INTRODUCTION Benign metastasising leiomyoma (BML) is a rare condition marked by well-differentiated smooth muscle tumours appearing outside the uterus in women with a history of uterine leiomyoma.Metastasis from leiomyoma is found to be most common in the lungs(79.5%),but other organs,including the heart,lymph nodes,spine and soft tissues,can also be affected.
文摘Alveolar soft tissue sarcoma is a rare malignant tumor of soft tissue,more common in young women,with deep soft tissues in the limbs and buttocks being the most prevalent sites.There are few reported cases in clinical practice.The clinical manifestations lack specificity and the imaging signs are diverse.This case presents ultrasound,MRI and PET/CT images of alveolar soft tissue sarcoma of the gluteus maximus muscle to enhance readers’understanding and awareness of the imaging signs of this rare disease in order to raise awareness of its diagnosis.The characteristics of this case are summarized and reported in combination with domestic literature.
文摘Soft tissue sarcomas(STS)are rare malignant tumors originating from mesoder-mal tissues with a poor prognosis,accounting for approximately 1%of all malig-nancies and comprising around 50 distinct subtypes.Conventional imaging mo-dalities,such as computed tomography(CT)and magnetic resonance imaging(MRI),primarily provide anatomical information,whereas 18F-fluorodeoxyglucose positron emission tomography/CT(18F-FDG PET/CT)integrates functional metabolic and anatomical imaging,serving as a critical complementary tool in the diagnosis and management of STS.This article reviews recent advances in the application of 18F-FDG PET/CT for STS.The advantages of 18F-FDG PET/CT in STS include:(1)Early detection of metabolic activity changes in tumors,partic-ularly when morphological alterations are insignificant;(2)Effective differen-tiation between benign and malignant soft tissue tumors,as well as aiding in distinguishing high-grade from low-grade sarcomas;(3)Identification of occult metastatic lesions,improving staging accuracy,and facilitating restaging in cases of recurrence or metastasis;(4)Utilization of parameters such as maximum stan-dardized uptake value and metabolic tumor volume to assist in tumor grading and prognostic evaluation;and(5)Monitoring treatment response to guide adjust-ments in personalized therapeutic strategies.However,18F-FDG PET/CT has limitations in diagnosis of certain STS subtypes(e.g.,myxoid liposarcoma),detection and biopsy of metastatic lymph nodes,necessitating integration with clinical evaluation and other imaging techniques.18F-FDG PET/CT is poised to play an increasingly vital role in the precision diagnosis and treatment of STS.
文摘Soft tissue sarcoma(STS)accounts for 1%of all malignant neoplasms in adults.Their diagnosis and management constitute a challenging target.They originate from the mesenchyme,and 50 subtypes with various cytogenetic profiles concerning soft tissue and bones have been recognized.These tumors mainly affect middle-aged adults but may be present at any age.Half of the patients have metastatic disease at the time of diagnosis and require systemic therapy.Tumors above 3-5 cm in size must be suspected of potential malignancy.A thorough history,clinical examination and imaging that must precede biopsy are necessary.Modern imaging techniques include ultrasound,computed tomography(CT),new magnetic resonance imaging(MRI),and positron emission tomography/CT.MRI findings may distinguish low-grade from high-grade STS based on a diagnostic score(tumor heterogeneity,intratumoral and peritumoral enhancement).A score≥2 indicates a high-grade lesion,and a score≤1 indicates a lowgrade lesion.For disease staging,abdominal imaging is recommended to detect early abdominal or retroperitoneal metastases.Liquid biopsy by detecting genomic material in serum is a novel diagnostic tool.A preoperative biopsy is necessary for diagnosis,prognosis and optimal planning of surgical intervention.Core needle biopsy is the most indicative and effective.Its correct performance influences surgical management.An unsuccessful biopsy means the dissemination of cancer cells into healthy anatomical structures that ultimately affect resectability and survival.Complete therapeutic excision(R0)with an acceptable resection margin of 1 cm is the method of choice.However,near significant structures,i.e.,vessels,nerves,an R2 resection(macroscopic margin involvement)preserving functionality but having a risk of local recurrence can be an acceptable choice,after informing the patient,to prevent an unavoidable amputation.For borderline resectability of the tumor,neoadjuvant chemo/radiotherapy has a place.Likewise,after surgical excision,adjuvant therapy is indicated,but chemotherapy in nonmetastatic disease is still debatable.The five-year survival rate reaches up to 55%.Reresection is considered after positive or uncertain resection margins.Current strategies are based on novel chemotherapeutic agents,improved radiotherapy applications to limit local side effects and targeted biological therapy or immunotherapy,including vaccines.Young age is a risk factor for distant metastasis within 6 mo following primary tumor resection.Neoadjuvant radiotherapy lasting 5-6 wk and surgical resection are indicated for highgrade STS(grade 2 or 3).Wide surgical excision alone may be acceptable for patients older than 70 years.However,locally advanced disease requires a multidisciplinary task of decision-making for amputation or limb salvage.
文摘Several problems about acupuncture and moxibustion for treatment of soft tissue injury are probed in the present paper. The author holds that for treatment of soft tissue injury with acupuncture and moxibustion, firstly, must clarify the lesion location, so as to understand pathogenic characteristics and select the best acupuncture forcing point; secondly, must distinguish different stages of the disease, so as to select the best proper acupuncture stimulation method according to different pathological mechanisms in acute and chronic stages. Finally, the author analyzes different stimulation characteristics and indications according to own experience on clinical commonly-used several acupuncture and moxibustion stimulation methods such as filiform needle, acupoint injection, micro-needle therapy including ear acupuncture, abdomen acupuncture, eye acupuncture and so on, and blood-letting puncturing and cupping, fire needle and small needle-knife, and puts forward own treatment points of view.
文摘BACKGROUND Diffuse large B-cell lymphoma(DLBCL)is the most common subtype of non�Hodgkin lymphoma,and patients with DLBCL typically present rapidly growing masses.Lymphoma involving muscle is rare and accounts for only 5%;furthermore,multiple muscles and soft tissue involvement of DLBCL is unusual.Due to unusual clinical manifestation,accurate diagnosis could be delayed.CASE SUMMARY A 61-year-old man complained of swelling,pain and erythematous changes in the lower abdomen.Initially,soft tissue infection was suspected,however,skin lesion did not respond to antibiotics.18Fluoro-2-deoxy-D-glucose(18F-FDG)positron emission tomography-computed tomography demonstrated FDG uptake not only in the skin and subcutaneous tissue of the abdomen but also in the abdominal wall muscles,peritoneum,perineum,penis and testis.DLBCL was confirmed by biopsy of the abdominal wall muscle and subcutaneous tissue.After intensive treatment including chemotherapy with rituximab,cyclophosphamide,doxorubicin,vincristine and prednisolone,central nervous system prophylaxis(intrathecal injection of methotrexate,cytarabine and hydrocortisone)and orchiectomy,he underwent peripheral blood stem cell mobilization for an autologous hematopoietic stem cell transplantation.Despite intensive treatment,the disease progressed rapidly and the patient showed poor outcome(overall survival,9 mo;disease free survival,3 mo).CONCLUSION The first clinical manifestation of soft tissue DLBCL involving multiple muscles was similar to the infection of the soft tissue.
文摘Summary： In this study we present our experiences with the reverse sural fasciocutaneous flap to reconstruct the distal lower limb soft tissue defects caused by traumatic injuries. These flap graftings were carried out from Oct. 2010 to Dec. 2012 in our department. The series consisted of 36 patients, including 21 men and 15 women with an average age of 46.2 years （14-83 years） and with a medium followp period of 18 months （12-24 months）. Of all the cases of acute trauma, there were 10 eases of trauma of distal tibia, 9 cases of trauma of perimalleolus, and 17 cases of trauma of midfoot and forefoot. Related risk factors in the patients were diabetes （2 cases）, advanced age （〉65 years, 3 cases） and ciga- rette smoking （6 cases）. The reverse flow sural island flap irrigation depended on lower perforators of the peroneal artery. The fasciocutaneous pedicle was 3-4 cm in width and the anatomical structures consisted of the superficial and deep fascia, the sural nerve, short saphenous vein, superficial sural artery together with an islet of subcutaneous cellular tissue and skin. The most proximal border of the flap was only 1.5 cm away from the popliteal skin crease and the pivot point was 5-7 cm above the tip of the lateral malleolus. All the flaps survived. No arterial crisis occurred in any case. The venous congestion occurred in 2 cases and got better after raising the limbs and bloodletting. Only in an old man, 1.5 cm necrosis of distal margin of his flap occurred and finally healed after continuous dressing change. One-stage skin grafting was performed, and all the donor sites were sutured and successfully healed. It was concluded that the reverse sural fasciocutaneous flap is safe and reliable to extend to the proximal third even near the popliteal skin crease. We also concluded this flap can be safely and efficiently used to treat patients with large and far soft-tissue defects from the distal leg to the forefoot with more versatility and it is easier to reach the recipient sites.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274342,11304353,11404245 and 11474042
文摘Elasticity is of profound significance to evaluating the function of a biological soft tissue. When the elasticity of a tissue is macroscopically changed, it means that the biological function of the tissue is abnormal and some disease or injury may occur. In the present work, an elastometer is developed to measure the elasticity of biological soft tissues. The measurement is based on the indentation method and the force is measured by the bending of the cantilever. The force-indentation data of the soft tissue is experimentally measured by this elastometer and Young＇s modulus of the tissue is calculated using the Hertz-Sneddon model. For comparison, a numerical model for the indentation method is established using the finite element method. The difference between the actual modulus and the measured modulus is discussed. The effect of the thickness of the specimen on the measurement is investigated. Young＇s moduli of beef, porcine liver and porcine kidney are experimentally measured. The results indicate that our elastometer is effective in measuring Young＇s modulus of a soft tissue quantitatively.
基金funded by the National Natural Science Foundation of China(Nos.81801006,31870953,81901048,81620108006,81991505,81921002,81801023,and 82100963)Shanghai Rising-Star Program(21QA1405400)+1 种基金the National Key Research and Development Program of China(No.2016YFC1102900)Innovative Research Team of High-Level Local Universities in Shanghai(No.SSMU-ZDCX20180900)。
文摘Following dental implantation,the characteristic bacterial milieu of the oral cavity may lead to peri-implant inflammation,which can negatively impact osseointegration and cause implant failure.To improve soft tissue sealing around the implant,enhance osseointegration,and improve implant success rates,this paper proposes a composite multifunctional coating(PHG)prepared using gelatin and polydopamine/hydroxyapatite nanoparticles,investigates the effects of this novel coating on cell adhesion,proliferation,antibacterial activity,osteogenic differentiation,and evaluates its immune-related properties.The PHG coating was proved to have satisfactory hydrophilicity and wettability for cell attachment.Furthermore,it improved the expression of adhesion-related genes and proteins in human gingival fibroblasts,indicating its adhesion-promoting effect.Additionally,bone marrow mesenchymal stem cells exhibited strong osteogenic differentiation potential and mineralization on PHG-coated surfaces.Notably,the PHG coating exhibited antibacterial activity against Streptococcus mutans,as well as anti-inflammatory effects,potentially via the regulation of macrophages.Therefore,the proposed PHG coating may promote soft tissue sealing and bone bonding,providing a potential strategy for the surface modification of dental implants.
基金This work was supported,in part,by the National Nature Science Foundation of China under grant numbers 61502240,61502096,61304205,61773219in part,by the Natural Science Foundation of Jiangsu Province under grant number BK20191401+1 种基金in part,by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)fundin part,by the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)fund.
文摘In order to solve the problem of high computing cost and low simulation accuracy caused by discontinuity of incision in traditional meshless model,this paper proposes a soft tissue deformation model based on the Marquardt algorithm and enrichment function.The model is based on the element-free Galerkin method,in which Kelvin viscoelastic model and adjustment function are integrated.Marquardt algorithm is applied to fit the relation between force and displacement caused by surface deformation,and the enrichment function is applied to deal with the discontinuity in the meshless method.To verify the validity of the model,the Sensable Phantom Omni force tactile interactive device is used to simulate the deformations of stomach and heart.Experimental results show that the proposed model improves the real-time performance and accuracy of soft tissue deformation simulation,which provides a new perspective for the application of the meshless method in virtual surgery.
文摘BACKGROUND Clear cell sarcoma(CCS)is a rare and highly malignant soft tissue tumor,usually occurring in the deep soft tissues of the distal tendons and aponeurosis of the extremities,especially the feet and knees.CCS originating in the head and neck is extremely rare.The clinical manifestations of CCS in the head and neck are not typical,and the imaging manifestations have certain characteristics,but the diagnosis still depends on pathological examination and genetic testing.CASE SUMMARY A 33-year-old male patient had paroxysmal headache for more than 4 years,accompanied by nausea and vomiting,which could be relieved after rest.Computed tomography angiography showed a left paraspinal soft tissue mass.Contrast-enhanced imaging showed obvious uneven enhancement with adjacent bone lytic destruction.Magnetic resonance imaging examination showed isosignal on T_(1)-weighted images,slightly high signal on T_(2)-weighted images(T_(2)WI),high signal on Tirm fat suppression sequence,significantly high signal on diffusion weighted imaging,and obvious and uneven enhancement.The lesion invaded the anterior medulla oblongata through the left atlantoaxial foramen and compressed the cervical spinal cord on T_(2)WI.Primary CCS of soft tissue was diagnosed by pathology and genetic examination.CONCLUSION CCS should be considered in the differential diagnosis of soft tissue tumors of the head and neck,and their diagnosis depends on pathological examination and genetic testing.
文摘BACKGROUND Active myofascial trigger points(TrPs)often occur in the upper region of the upper trapezius(UT)muscle.These TrPs can be a significant source of neck,shoulder,and upper back pain and headaches.These TrPs and their related pain and disability can adversely affect an individual’s everyday routine functioning,work-related productivity,and general quality of life.AIM To investigate the effects of instrument assisted soft tissue mobilization(IASTM)vs extracorporeal shock wave therapy(ESWT)on the TrPs of the UT muscle.METHODS A randomized,single-blind,comparative clinical study was conducted at the Medical Center of the Egyptian Railway Station in Cairo.Forty patients(28 females and 12 males),aged between 20-years-old and 40-years-old,with active myofascial TrPs in the UT muscle were randomly assigned to two equal groups(A and B).Group A received IASTM,while group B received ESWT.Each group was treated twice weekly for 2 weeks.Both groups received muscle energy technique for the UT muscle.Patients were evaluated twice(pre-and posttreatment)for pain intensity using the visual analogue scale and for pain pressure threshold(PPT)using a pressure algometer.RESULTS Comparing the pre-and post-treatment mean values for all variables for group A,there were significant differences in pain intensity for TrP1 and TrP2(P=0.0001)and PPT for TrP1(P=0.0002)and TrP2(P=0.0001).Also,for group B,there were significant differences between the pre-and post-treatment pain intensity for TrP1 and TrP2 and PPT for TrP1 and TrP2(P=0.0001).There were no significant differences between the two groups in the post-treatment mean values of pain intensity for TrP1(P=0.9)and TrP2(P=0.76)and PPT for TrP1(P=0.09)and for TrP2(P=0.91).CONCLUSION IASTM and ESWT are effective methods for improving pain and PPT in patients with UT muscle TrPs.There is no significant difference between either treatment method.
基金Supported by the National Natural Science Foundation of China(No.51175373)New Century Educational Talents Plan of Chinese Education Ministry(No.NCET-10-0625)+1 种基金Key Technology and Development Program of Tianjin Municipal Science and Technology Commission(No.12ZCDZSY10600)Tianjin Key Laboratory of High Speed Cutting&Precision Machining(TUTE)(2013120024001167)
文摘The force model during needle insertion into soft tissue is important for accurate percutaneous intervention.In this paper,a force model for needle insertion into a tissue- equivalent material is presented and a series of experiments are conducted to acquire data from needle soft- tissue interaction process.In order to build a more accurate insertion force model,the interaction force between a surgical needle and soft tissue is divided into three parts:stiffness force,friction force,and cutting force.The stiffness force is modeled on the basis of contact mechanics model.The friction force model is presented using a modified Winkler' s foundation model.The cutting force is viewed as a constant depending on a given tissue.The proposed models in the paper are established on the basis of the mechanical properties and geometric parameters of the needle and soft tissue.The experimental results illustrate that the force models are capable of predicting the needle-tissue interaction force.The force models of needle insertion can provide real-time haptic feedback for robot-assisted procedures,thereby improving the accuracy and safety of surgery.
文摘Objective: A pilot study to test the feasibility and efficacy of high dose IFO and standard dose ADR and DTIC with G-CSF support in treatment of advanced soft tissue sarcoma (STS). Methods: 35 patients of no prior chemotherapy with metastatic or locally advanced unresectable STS were treated by this regimen, including 18 rhabdomyosarcomas, 7 malignant fibrous histiocytomas, 2 neurofibrosarcomas, 2 fibrosarcomas, 2 leiomyosarcomas, 2 synoviosarcomas, and 2 malignant hemangiopericytomas. IFO dose was 2 g/m2 on day 1–5 (with mesna uroprotection), ADR 50mg/m2 on day 1 and DTIC 250 mg/m2 on day 1–5. G-CSF (2 μg/kg/d) was administered on day 6 to 15 or until recovery of leukocytes account. The cycles were repeated every 3 weeks. Result: There were five complete responses (CR including pathologic CR) and eleven partial responses for overall 46% objective response rate. Most responses were observed within two cycles. The median survival was 15 months. Following CR, two patients remain disease free at 45 and 28 months, respectively. 6/120 (5%) cycles were complicated by grade IV neutropenia, 46/120 (38%) cycles had grade III neutropenia. No patients had treatment-related deaths. Nonhematologic toxicity consisted predominantly of anorexia and vomiting. No other severe toxicities were seen, especially no severe cardiotoxicity. Conclusion: This regimen is well tolerated and has substantial benefits for patients with advanced soft tissue sarcomas.
基金National Major Scientific Research Instrument Development Project of China(Grant No.81827804)Zhejiang Provincial Natural Science Foundation of China(Grant No.LSD19H180004)+1 种基金Science Fund for Creative Group of NSFC(Grant No.51821903)National Natural Science Foundation of China(Grant No.51665049).
文摘The simulation and planning system(SPS)requires accurate and real-time feedback regarding the deformation of soft tissues during the needle insertion procedure.Traditional mechanical-based models such as the finite element method(FEM)are widely used to compute the deformations of soft tissue.However,it is difficult for the FEM or other methods to find a balance between an acceptable image fidelity and real-time deformation feedback due to their complex material properties,geometries and interaction mechanisms.In this paper,a Kriging-based method is applied to model the soft tissue deformation to strike a balance between the accuracy and efficiency of deformation feedback.Four combinations of regression and correlation functions are compared regarding their ability to predict the maximum deformations of ten characteristic markers at a fixed insertion depth.The results suggest that a first order regression function with Gaussian correlation functions can best fit the results of the ground truth.The functional response of the Kriging-based method is utilized to model the dynamic deformations of markers at a series of needle insertion depths.The feasibility of the method is verified by investigating the adaptation to step variations.Compared with the ground truth of the finite element(FE)results,the maximum residual is less than 0.92 mm in the Y direction and 0.31 mm in the X direction.The results suggest that the Kriging metamodel provides real-time deformation feedback for a target and an obstacle to a SPS.
基金This work was supported in part by the National Nature Science Foundation of China(No.61502240,61502096,61304205,61773219)Natural Science Foundation of Jiangsu Province(BK20150634,BK20141002).
文摘Real-time performance and accuracy are two most challenging requirements in virtual surgery training.These difficulties limit the promotion of advanced models in virtual surgery,including many geometric and physical models.This paper proposes a physical model of virtual soft tissue,which is a twist model based on the Kriging interpolation and membrane analogy.The proposed model can quickly locate spatial position through Kriging interpolation method and accurately compute the force change on the soft tissue through membrane analogy method.The virtual surgery simulation system is built with a PHANTOM OMNI haptic interaction device to simulate the torsion of virtual stomach and arm,and further verifies the real-time performance and simulation accuracy of the proposed model.The experimental results show that the proposed soft tissue model has high speed and accuracy,realistic deformation,and reliable haptic feedback.
