Preliminary experimental study on splenic hemodynamics of radiofrequency ablation for the spleen

Purpose: To test the splenic blood flow change after radiofrequency ablation (RFA) of the spleen in a porcine experimental model.

Material and methods: Six pigs underwent RFA of the spleen via laparotomy. During the procedure of RFA, clamping of splenic artery (one) and both splenic artery/vein (one) was also performed. Measurement of blood flow of both splenic artery (SA) and splenic vein (SV) with flow-wire at pre- and post-RFA of the spleen was also performed.

Results: Ablated splenic lesions were created as estimating ～50% area of the spleen in all pigs. Resected specimens reveal not only the coagulated necrosis but also the congestion of the spleen. On the SA hemodynamics, maximum peak velocity (MPV) changed from 37?±?7?to 24?±?8?cm/s (normal), 11?to 10?cm/s (clamp of the SA), and 12?to 7.5?cm/s (clamp of both SA/SV), respectively. On the SV hemodynamic, MPV changed from 15?±?5?to 13?±?4?cm/s (normal), 17?to 15?cm/s (clamp of the SA), and 17?to 26?cm/s (clamp of both SA/SV), respectively.

Conclusions: RFA of the spleen could induce coagulation necrosis and reduce the splenic arterial blood flow.     

Laparoscopic liver packing to protect surrounding organs during thermal ablation

Abstract

Purpose: To evaluate the feasibility of liver packing for the prevention of injury to adjacent organs during thermal ablation of liver tumors. Material and methods: Between January 2005 and March 2010, 47 (52 sessions) patients with non-resectable liver tumors were treated and their tumors (55 primary carcinomas and 65 metastases, 1–12) were isolated from adjacent organs by laparoscopic liver mobilization and packing. Stereotactic radiofrequency ablation (SRFA) comprised body fixation, contrast-enhanced CT, 3-D planning, navigation, needle placement, control CT of needle positions (with image fusion), thermal ablation and control CT (with image fusion). Liver packing was removed laparoscopically thereafter. Complications, primary success and local recurrence rates were analyzed. Results: A total of 120 liver lesions with a median size of 2.4 cm (range 1–15 cm) were treated. Laparoscopic packing could be performed in all patients. The primary success rate of ablation was 91.6% (110/120) and the local recurrence rate was 4.5% (5/110). There was one perioperative death (1.9%). All remaining complications could be managed by radiological interventions. Despite broad surface contact thermal injury of surrounding organs could be prevented in all patients. Conclusion: Liver packing presents a viable and safe option for RFA of tumors with broad surface contact to surrounding organs with excellent local tumor control.     

植入式水冷915 MHz与2450 MHz微波消融的猪活体肝脏的实验对比

目的 对比植入式水冷915 MHz和2450 MHz微波在活体猪肝脏消融实验中的消融范围及热场特性.方法 根据频率不同分两组实验.915 MHz和2450 MHz微波天线沿特制支架插入活体猪肝脏后,平行天线裂隙旁开5 mm、10 mm、15 mm、20 mm 间距的A(5,0)、B(10,0)、C(15,0)、D(20,0)四点分别放置测温针,均以60 W、600 s条件辐射,计算机采集测温数据,消融后测量消融区范围并比较两组消融范围的大小,分析温升曲线并比较两组的温升速率及所达最高温度.结果 915 MHz微波较2450 MHz微波在活体猪肝消融中可获得更大的消融横径和纵径;915 MHz微波和2450 MHz微波两者距离天线越近的位点温升速率越快,所达最高温度亦越高;对应B、C、D点上915 MHz微波较2450 MHz微波具有更快的温升速率及更高的温度.结论 915 MHz微波与2450 MHz微波相比,915MHz微波可获得更大的消融范围,具有更高的热效率.     

Changes in peripheral blood T-cell balance after percutaneous tumor ablation

Purpose: To evaluate the changes in T-cell balance in peripheral blood following percutaneous tumor ablation.

Material and methods: Patients underwent thermal ablation including radiofrequency (n?=?9) and microwave ablation (n?=?5), or cryoablation (n?=?5). Target tumors were located in the lung (n?=?7), soft tissue (n?=?5), liver (n?=?4), and bone (n?=?3). Patient peripheral blood samples were collected before and within 14?days after ablation. Peripheral blood populations of cytotoxic T-cells (CTL), type-1 (T_h1) and type-2 helper T-cells (T_h2), and regulatory T-cells (T_reg) were measured using flow cytometry. Changes in CTL/T_reg and T_h1/T_h2 ratios before and after ablation therapy were compared using paired t-tests.

Results: Peripheral blood CTL population (27.5?±?2.1% to 30.2?±?2.5%, p?reg ratios (18.8?±?3.7% to 21.6?±?3.6%, p?reg ratios was found after heat-based ablation (18.0?±?4.4% to 21.6?±?4.7%, p?p?=?.92). T_h1/T_h2 ratio (13.7?±?3.0% to 17.2?±?3.5%, p?=?.12) remained unchanged after ablation.

Conclusion: Ablation therapy alters the T-cell balance by increasing the systemic CTL/T_reg, ratio. Heat-based ablation might be a more effective approach than cryoablation to enhance systemic anti-tumor immunity.     

Optimal approach for complete liver tumor ablation using radiofrequency ablation: a simulation study

Purpose: To investigate the effect of radiofrequency ablation (RFA) electrode trajectory on complete tumor ablation using computational simulation.

Material and methods: The RFA of a spherical tumor of 2.0?cm diameter along with 0.5?cm clinical safety margin was simulated using Finite Element Analysis software. A total of 86 points inside one-eighth of the tumor volume along the axial, sagittal and coronal planes were selected as the target sites for electrode-tip placement. The angle of the electrode insertion in both craniocaudal and orbital planes ranged from ?90° to +90° with 30° increment. The RFA electrode was simulated to pass through the target site at different angles in combination of both craniocaudal and orbital planes before being advanced to the edge of the tumor.

Results: Complete tumor ablation was observed whenever the electrode-tip penetrated through the epicenter of the tumor regardless of the angles of electrode insertion in both craniocaudal and orbital planes. Complete tumor ablation can also be achieved by placing the electrode-tip at several optimal sites and angles.

Conclusions: Identification of the tumor epicenter on the central slice of the axial images is essential to enhance the success rate of complete tumor ablation during RFA procedures.     

新型腔内射频消融导管消融离体猪肝

目的 观察新型腔内射频消融导管对离体猪肝(肝实质、栓子模型)的消融效果。方法 应用EMcision Habib腔内射频消融导管及RITA射频发生器对新鲜离体猪肝肝实质及栓子模型进行消融,输出功率分别为5 W、10 W、15 W和20 W,消融时间分别为60 s、90 s和120 s,观察消融灶组织凝固形态及范围。结果 消融肝实质时,输出功率为10 W、延长消融时间(90 s延长至120 s),输出功率为15 W、延长消融时间(60 s延长至90 s)以及消融时间为60 s和90 s、增加输出功率(15 W增加至20 W)获得的消融灶长径增加(P均<0.05),而宽径增加不明显(P均>0.05)。消融栓子模型时,输出功率为10 W、延长消融时间(90 s延长至120 s),以及消融时间为60 s、增加输出功率(15 W增加至20 W)均可增加消融灶长径(P均<0.05),而宽径增加不明显(P均>0.05)。肉眼见所有消融灶附着处血管管壁颜色均与邻近血管管壁无差异。结论 采用EMcision Habib腔内射频导管消融离体猪肝可出现明确的消融范围,且对管道壁无明显损伤。     

Multipronged ethanol ablation combined with TACE for intermediate hepatocellular carcinoma

Purpose: To retrospectively investigate the efficacy of multipronged ethanol ablation with or without transarterial chemoembolization (TACE) in the treatment of intermediate hepatocellular carcinoma (HCC) (3.1-5.0?cm in diameter) at high-risk locations .

Material and methods: From March 2009 to April 2014, 25 consecutive patients with intermediate HCC who underwent multipronged ethanol ablation combined with TACE were included in the combination treatment group, while 50 patients who underwent multipronged ethanol ablation alone were included in the control group.

Results: Primary technique effectiveness was achieved in 70 patients (25/25, 100% in the combination treatment group; 45/50, 90% in the control group; p?=?.162). The local tumor progression (LTP) rates at 1, 3, 5, and 7?years were 8.0%, 24.0%, 24.0%, and 24.0% in the combination treatment group, respectively, which were significantly lower than those in the control group (24.4%, 44.1%, 66.5% and 66.5%, respectively; p?=?.043). However, no significant differences of overall survival and disease-free survival were found between the two groups (p?=?.996 and .974, respectively).

Conclusion: Multipronged ethanol ablation combined with TACE could improve local tumor control for patients with intermediate HCC at high-risk locations when compared with multipronged ethanol ablation alone, although the survival outcomes were comparable.     

NaK alloy-induced in vivo tumor ablation therapy

Purpose: Alkali metal ablation is newly emerging as an effective, economic and minimally invasive ablation therapy. This study is dedicated to demonstrate the high efficiency of NaK alloy ablation on in vivo tumors with different stages in mice.

Material and methods: Panc02 tumor cells were injected into 21 female C57B/L mice, which were divided into three groups. Two experimental groups of mice received the same percutaneous NaK alloy injection for a week apart. The inner temperature response and surface temperature distribution were measured using a thermal couple and an infrared camera. After each ablation experiment, two mice in each group were chosen randomly to make pathological sections. The tumor volumes were measured once every two days. At the end, all tumors were cut off to calculate the tumor inhibition rates.

Results: The NaK alloy-induced ablation therapy produced an obvious temperature increase (85?°C) in the ablation region and the high temperature distribution was relatively concentrated. The histopathology sections showed that developing stage tumors received incomplete destruction of the malignant cells compared with early stage tumors. The tumor inhibition rate in the early and developing tumor treatment groups were 88.5% and 67.6%, respectively.

Conclusions: This technology provides a nearly thorough ablation treatment for early stage tumors and also a palliative treatment for developing tumors.     

Irreversible electroporation for the treatment of cardiac arrhythmias

Introduction: Cardiac ablation is an established treatment modality for the management of patients with cardiac arrhythmias. Current approaches to cardiac ablation employ thermal based energy to achieve lesions (damage) within the heart. There are many shortcomings and limitations of thermal based approaches. Electroporation (DC energy) is a non-thermal alternative approach to ablation that has shown significant promise in animal studies.

Areas covered: An extensive review of the literature on the application of electroporation for ablation (both cardiac and collateral cardiac tissue) was undertaken. This review explores irreversible electroporation as a cardiac ablation modality. Specifically, it focuses and explains the biophysics of electroporation, the limitations of current thermal based approaches and examines the current data published on electroporation cardiac ablation.

Expert commentary: Electroporation is a fast-growing novel ablation modality that has many advantages over current thermal based approaches. Current research in animal models shows its can be safely and efficaciously applied to the heart. Although further research is required, electroporation represents an appealing option for the ablation cardiac arrhythmias.     

Saphenous vein ablation with a new cyanoacrylate glue device: a systematic review on 1000 cases

Background: To review published evidence regarding an n-butyl-cyanoacrylate (NBCA) injection device for great (GSV) and small (SSV) saphenous vein incompetence in terms of occlusion rate, postoperative complications and quality of life improvement.

Material and methods: International bibliographic databases (PubMed, EMBASE, Scopus) were searched to identify possible target articles. The only inclusion criterion was the use of the Variclose^® system (Biolas, Ankara, Turkey) for superficial vein insufficiency. Exclusion criteria were case reports, review, meta-analysis, article with <6-month follow-up data, abstracts and congress presentations. PRISMA guidelines were used to lead articles selection.

Results: Seven studies were included in the final data analysis. A total of 918 patients (1000 limbs) underwent an NBCA procedure for GSV (947 cases) or SSV (53 cases) incompetence. The average procedure duration was 11.7?min. The most common postoperative complications were postoperative pain (4.8%) and superficial vein thrombosis (2.1%). No deep vein thrombosis or pulmonary embolism cases were described. The occlusion rates at six, 12 and 30?months were 97.3%, 96.8% and 94.1%, respectively.

Conclusion: NBCA injection with the Variclose device seems to be a feasible, effective and safe treatment in GSV incompetence. Long-term follow-up studies and randomized controlled trials are needed to achieve high-quality evidence.     

Cannula-guided snare with endoclip to assist in endoscopic submucosal dissection: an in vivo animal study

Background and objective: Assisted endoscopic submucosal dissection (ESD) with mucosal traction remains a challenge. This study explored an approach to assist in esophageal, gastric, colonic, and rectal ESD through a cannula-guided snare with endoclips (CSC-ESD), and aimed to preliminarily evaluate its feasibility in an in vivo porcine model.

Material and methods: Forty-seven digestive tract mucosae in six pigs were resected using CSC-ESD. The operative time, operative success rate, en bloc resection rate, and intraoperative complications were evaluated.

Results: The mean diameter of 12 resected esophageal mucosae was 4.4?±?1.7?cm and the mean operative time was 24?±?8?min. The mean diameter of 20 resected gastric mucosae was 3.8?±?0.9?cm and the operative time was 35?±?8?min. The mean diameter of 15 resected colonic and rectal mucosae was 3.6?±?1.0?cm and the operative time was 34?±?8?min. In all 47 resected mucosae, the en bloc resection rate was 100%, the operative success rate was 100%, and the intraoperative perforation rate was 4.3% (2/47) in the colon. No mucosal bruising or massive bleeding occurred during surgery.

Conclusion: The results indicated that this novel assistive method is feasible in esophageal, gastric, colonic and rectal ESD. The further research is worthwhile.     

双导微波发射增大肝脏凝固范围的实验研究

目的　采用双导微波发射 ,增大肝内凝固坏死范围 ,为临床一次性完全覆盖凝固较大肿瘤提供依据。方法　用离体新鲜猪肝 ,选择三种作用条件 ( 3 0W ,10min ;3 5W ,10min ;40W ,10min) ,在超声导向下将两根微波天线按不同间距同深度植入肝脏 ,采用同时和分时发射微波 ,术后剖视固化灶大小、形态。结果　同时双导在 3 5W ,10min两针距 1.5cm时 ,凝固灶范围为 5 .8cm× 5 .2cm× 5 .0cm ,形态呈类球形 ,分时双导在同等条件下所形成凝固灶范围为 5 .5cm× 4.6cm× 4.2cm ,形态呈蝶形 ,融合欠佳。双导两针中间较两针外侧相对应处温度存在明显温度差 ,且升温迅速 ,高温持续时间长。结论　双导微波发射 ,凝固坏死范围明显增大 ,为临床治疗较大肝肿瘤提供了支持 ;同时双导凝固效果好于分时双导 ;双导微波发射所致热场不是两个孤立热场的简单线性叠加。     

Novel endoscopic multi-firing-clip applicator for endoscopic closure of large colonic perforations

Background: Existing endoclip closure devices have difficulty in closing large colonic perforation. We developed a novel endoscopic multi-firing-clip applicator (EMFCA) system to address these limitations, and report on its initial evaluation.

Material and methods: The functionality and efficacy of the prototype EMFCA equipped with re-openable clamp and preloaded with four clips were assessed using standardized 1.5?cm incisions created in ex-vivo porcine colonic segments. Endoscopic closure of the lacerations with two, three and four clips (n?=?five for each group) was followed by measurement of the leakage pressure of the three groups. Finite element analysis (FEA) was performed to validate the clip behavior and reliability during deployment.

Results: All 15 perforations were sealed without leakage until fully distended. The leakage pressures of colonic lacerations sealed with two, three, and four clips were 26.1?±?2.8?mmHg, 37.3?±?7.3?mmHg and 42.3?±?7.4?mmHg, respectively. The mean operation time to deploy one clip was 25.4?±?5.2?seconds. On FEA, the deformation of the shape of the clip matched that of the intended design, with each clip sustaining a maximum stress of 648.5?MPa without any material failure during deployment.

Conclusions: These initial results confirm the efficacy of the EMFCA prototype system for endoscopic closure of colonic perforations.     

Prediction of abortion using three-dimensional ultrasound volumetry of the gestational sac and the amniotic sac in threatened abortion

PURPOSE.: To determine whether gestational sac volume (GSV) or amniotic sac volume (ASV) and/or the difference between them can predict abortion in women with first-trimester threatened abortion. METHODS.: Ninety patients between 6 and 12 weeks of gestation presenting with vaginal bleeding were studied. Seventy-six delivered after 24 weeks of gestation (group A) and 14 aborted before 20 weeks of gestation (group B). All patients had a singleton viable pregnancy demonstrated by transvaginal ultrasound. Gestational sac and amniotic sac volumes were measured in all the patients using three-dimensional transvaginal ultrasound with Virtual Organ Computer-aided Analysis software, and the gestational sac volume - amniotic sac volume (GSV - ASV) was calculated. RESULTS.: The groups did not differ in terms of age, parity, number of previous abortions, or term deliveries. The GSV (group A: mean 32.0 ± 27.7 cm(3) ; group B: 26.7 ± 29.1 cm(3) ) and the ASV (group A: 21.1 ± 25.5 cm(3) ; group B: 20.6 ± 26.0 cm(3) ) were not statistically different, while the GSV - ASV was significantly smaller in group B (aborting before week 20) (group A: 10.9 ± 10.9 cm(3) ; group B: 6.1 ± 8.6 cm(3) ; p < 0.05). Using receiver operator curves, the area under the curve for predicting normal pregnancy outcome of the GSV - ASV measurement was 0.654. When the GSV - ASV was 1.8 cm(3) or less, abortion was predicted with 84% sensitivity and 43% specificity. CONCLUSIONS.: The measurement of the GSV and the ASV are not good predictors of abortion in patients with first-trimester vaginal bleeding, whereas the use of the GSV - ASV may be helpful in predicting the outcome of pregnancy. ? 2012 Wiley Periodicals, Inc. J Clin Ultrasound 40:389-393, 2012.     

Synchronous CT-guided Brachytherapy in Patients at Risk for Incomplete Interstitial Laser Ablation of Liver Malignancies

Objectives: Indications for additional brachytherapy after CT guided interstitial laser ablation in patients with liver malignancies.Materials and methods: Fourteen patients with eighteen liver metastasis received high-dose-rate (HDR) brachytherapy directly following MR-guided interstitial laser ablation. Indications for additional brachytherapy were as follows: tumor size >5 cm, adjacent central bile duct or adjacent major vessels causing unfavourable cooling effects for thermal ablation, and technical failures of laser ablation. Dosimetry for brachytherapy was performed using three-dimensional CT data acquired after percutaneous applicator positioning for laser treatment. In average, a minimal dose of 17 Gy inside the tumor margin was applied (range: 10–20 Gy).Results: The mean tumor size was 4.3 cm (2.1–7.2 cm). The mean liver volume receiving ≥5 Gy was 16% of the liver total (2–40%). Severe complications were recorded in 1 patient. One patient developed acute liver failure possibly related to accidental continuation of oral capecitabine treatment (5 FU). Commonly encountered moderate increase of liver enzymes was observed. Local control rates after 9 months were 93% and after 12 month 86% for combined treatment with brachytherapy, respectively.Conclusion: CT guided brachytherapy using 3D CT data for dosimetry is safe and effective in combination with interstitial laser ablation. Brachytherapy as an additional treatment displayed sincere advantages over thermal ablation alone in critical location of the tumor.     

Functional repair of the great saphenous vein by external valvuloplasty reduces the vein's diameter: 6-month results of a multicentre study

ObjectivesExternal valvuloplasty (eVP) is a reconstructive surgical method to repair the function of the terminal and preterminal valves. We evaluated the 6-month outcomes of eVP regarding the diameter of the great saphenous vein (GSV).MethodsPatients from five vein centres were included in this observational study. Follow-up involved detailed duplex sonography of the GSV. The venous clinical severity score (VCSS) and the C class of the clinical, aetiologic, anatomic and pathophysiologic (CEAP) classification were recorded.ResultsWe enrolled 210 patients, with a follow-up rate of 58%; eVP was sufficient in 95.24% of the patients. The GSV diameters decreased significantly from 4.4 mm (standard deviation (SD): 1.39) to 3.9 (SD: 1.12), 4 cm distal to the saphenofemoral junction (SFJ); from 3.7 mm (SD: 1.10) to 3.5 mm (SD: 1.02) at the mid-thigh; from 3.6 mm (SD: 1.14) to 3.3 mm (SD: 0.94) at the knee and from 3.1 mm (SD: 0.99) to 2.9 mm (SD: 0.78) at the mid-calf. VCSS decreased significantly from 4.76 (SD: 2.13) preoperatively to 1.77 (SD: 1.57) 6 months postoperatively.ConclusionsGSV function can be restored by eVP; diameters over the total length of the GSV decreased significantly.     

Effects of modified constraint-induced movement therapy on the lower extremities in patients with stroke: a pilot study

Purpose: This study aimed to qualify the improvements of modified constraint-induced movement therapy (m-CIMT) on the lower limb of stroke patients via assessing the centre of mass (COM) displacement and the basic gait parameters.

Methods: A total of 22 hemiplegic patients after stroke with first-time clinical cerebral infarction or haemorrhagic cerebrovascular accident were included in this study from May to December, 2014. The patients were randomly divided into m-CIMT group and the conventional therapy group (control group), and received corresponding training for five days/week for four weeks. The COM displacement and gait parameters were assessed by three-dimensional segmental kinematics method in pre-intervention and post- intervention therapy.

Results: After four weeks of m-CIMT, the COM displacement on sagittal plane of paretic leg during stance phase was increased (pre: 91.04?±?4.39?cm, post: 92.38?±?4.58?cm, p?p?p?Conclusion: The m-CIMT intervention improves the COM displacement in sagittal and frontal plane, as well as gait parameters. These suggest that m-CIMT intervention may be feasible and effective for the rehabilitation of hemiplegic gait.

• Implications for Rehabilitation

• Segmental kinematics method was used to estimate the displacement of the COM.

• m-CIMT interventions improved the COM displacement of patients after stroke.

• m-CIMT interventions improved the hemiplegic gait parameters.

     

灰阶超声造影在肝外伤微波凝固治疗的实验研究

目的探讨灰阶超声造影在肝外伤微波凝固治疗中的应用价值。方法开腹状态下建立猪II级肝外伤伴活动性出血模型32处,微波凝固治疗功率分别采用70W和80W,时间5min。分别于治疗前、后应用常规超声及灰阶超声造影观察肝内损伤区的变化。结果常规超声难以显示肝外伤后所致的活动性出血。灰阶超声造影由于能清晰显示损伤区内的活动性出血,可实时引导将微波电极准确放置在肝内活动性出血部位。微波凝固治疗后,70W、80W两组治疗区呈长径分别为[(4.61±0.39)cm,(4.71±0.57)cm](t=-0.48,P>0.05)、短径分别为[(3.03±0.60)cm,(2.77±0.41)cm](t=1.14,P>0.05)的近似椭圆形无回声区,其中心部除针道呈极亮的强回声外均未见增强,呈负性显影;而56.2%(9/16)的70W治疗区和37.5%(6/16)的80W治疗区周边部可见少许线状增强。病理学证实,微波治疗区中心部汇管区的血管呈不同程度的退变坏死,肝细胞退变坏死,而周边部以肝细胞退变坏死为主要表现,血管坏死不明显。结论灰阶超声造影可用于实时引导微波电极的置入和术后疗效的判断,在肝外伤微波凝固治疗中具有一定的应用价值。     

Evidence-based cross validation for acoustic power transmission for a novel treatment system

Introduction: The novel Trans-Fusimo Treatment System (TTS) is designed to control Magnetic Resonance guided Focused Ultrasound (MRgFUS) therapy to ablate liver tumours under respiratory motion. It is crucial to deliver the acoustic power within tolerance limits for effective liver tumour treatment via MRgFUS. Before application in a clinical setting, evidence of reproducibility and reliability is a must for safe practice.

Materials and methods: The TTS software delivers the acoustic power via ExAblate-2100 Conformal Bone System (CBS) transducer. A built-in quality assurance application was developed to measure the force values, using a novel protocol to measure the efficiency for the electrical power values of 100 and 150W for 6s of sonication. This procedure was repeated 30 times by two independent users against the clinically approved ExAblate-2100 CBS for cross-validation.

Results: Both systems proved to deliver the power within the accepted efficiency levels (70–90%). Two sample t-tests were used to assess the differences in force values between the ExAblate-2100 CBS and the TTS (p?>?0.05). Bland-Altman plots were used to demonstrate the limits of agreement between the two systems falling within the 10% limits of agreement. Two sample t-tests indicated that TTS does not have user dependency (p?>?0.05).

Conclusions: The TTS software proved to deliver the acoustic power without exceeding the safety levels. Results provide evidence as a part of ISO13485 regulations for CE marking purposes. The developed methodology could be utilised as a part of quality assurance system in clinical settings; when the TTS is used in clinical practice.