Microwave ablation in the spleen for treatment of secondary hypersplenism: a preliminary study. AJR Am J Roentgenol. 2011;196:692-696. [PMID: 21343515 DOI: 10.2214/ajr.10.4193]

Ultrasound-guided Microwave Ablation in the Management of Symptomatic Uterine Myomas: A Systematic Review and Meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the clinical effects and safety of ultrasound-guided microwave ablation (MWA) for the treatment of symptomatic uterine myomas.

DATA SOURCES

We searched PubMed, Web of Science Core Collection, Cochrane Library, Embase, Scopus, and Google Scholar for studies from January 2000 to January 2021.

METHODS OF STUDY SELECTION

We included all studies that reported the clinical outcomes of ultrasound-guided MWA in women with symptomatic uterine myomas. Two researchers conducted the study selection according to the screening criteria.

TABULATION, INTEGRATION, AND RESULTS

We evaluated the risk of bias and evidence quality using the Newcastle-Ottawa scale. Two researchers independently extracted information from the included studies. We extracted the standardized mean difference (SMD) and pooled proportion with a 95% confidence interval (CI) for the outcome measures of interest. A total of 10 studies representing 671 patients were included. The Uterine Fibroid Symptom and Quality of Life (UFS-QoL) questionnaire was used to assess the clinical effects. Compared with baseline, the UFS scores decreased significantly (SMD 3.37; 95% CI, 2.27-4.47; p <.001; reduction rate 65.9%), QoL scores increased significantly (SMD -3.12; 95% CI, -3.93 to -2.30; p <.001; rate of increase 72.0%), and hemoglobin concentration increased significantly (SMD -2.13; 95% CI, -3.44 to -0.81; p = .002; rate of increase 30.3%) at follow-up. The mean operation time was 34.48 minutes (95% CI, 22.82-46.13; p <.001). The rate of reduction in myoma volume after MWA was 85.3% (95% CI, 82.7%-88.0%, p <.001). No major adverse event was reported, and the incidence of minor adverse events was 21.1% (95% CI, 15.1%-27.0%, p <.001).

CONCLUSION

Ultrasound-guided MWA is an effective and safe minimally invasive therapy for symptomatic uterine myomas.

Microwave ablation in the spleen versus partial splenic artery embolisation: A new technique for hypersplenism in cirrhosis

BACKGROUND AND STUDY AIMS

Splenectomy has been associated with high perioperative morbidity and mortality. Partial splenic artery embolisation (PSE) was found to be an effective and safer method but with numerous complications. Local thermal ablative techniques such as microwave ablation (MWA) have been tried and were found to be safe and effective alternatives. This randomised controlled study aimed to compare the efficacy and safety of MWA versus PSE in the treatment of hypersplenism in patients with post-hepatitis C cirrhosis.

PATIENTS AND METHODS

In total, 40 patients with post-hepatitis C cirrhosis complicated with hypersplenism were randomised into two groups: Group I: 20 patients treated with percutaneous MWA of splenic parenchyma under ultrasound guidance and Group II: 20 patients treated with PSE using Embosphere.

RESULTS

There was a significant increase in haemoglobin levels in group I compared with group II after 3months of follow-up. However, White blood cell (WBC) count and platelets significantly increased more in group II than in group I after 1month. Postprocedure significant hyperbilirubinaemia, hypoalbuminaemia, decreased prothrombin concentration, and increased creatinine levels were encountered in group II only. There was a significant increase in postoperative complications in group II compared to group I, and a single case of mortality was reported in group II.

CONCLUSION

MWA and PSE were comparably effective; however, MWA was safer than PSE, which caused serious adverse events and mortality. MWA appears to be a good alternative for the treatment of hypersplenism in patients with cirrhosis and portal hypertension.

Status and advancement of microwave ablation in China

Tumour ablation is defined as the direct application of chemical or thermal therapy to eradicate or substantially destroy a tumour. Currently, minimally invasive ablation techniques are available for the local destruction of focal tumours in multiple organ sites. Microwave ablation (MWA) is premised on the biological response of solid tumours to tissue hyperthermia, and it is a relatively low-risk procedure. Due to several advantages of MWA, including higher thermal efficiency, higher capability for coagulating blood vessels, faster ablation time and the simultaneous application of multiple antennae, MWA could be a promising minimally invasive ablation technique for the treatment of solid tumours. Therefore, the use of MWA has developed rapidly in China during the last decade. Many successful studies have been performed, and widespread use has been achieved for multiple types of tumours in China, especially for liver cancer. This review will describe the state-of-the-art of MWA in China, including the development of MWA equipment and its application in the treatment of multiple types of tumours.

Hepatectomy combined with microwave ablation of the spleen for treatment of hepatocellular carcinoma complicated with splenomegaly: A retrospective study

The present retrospective study aimed to investigate the mid-term safety and efficacy of hepatectomy combined with microwave ablation of the partial spleen for treatment of liver cancer complicated with hypersplenism. A retrospective analysis was performed on 23 patients who underwent hepatectomy combined with microwave ablation of the partial spleen for liver cancer, complicated with hypersplenism that was secondary to cirrhosis. The splenic and ablated volumes were calculated according to a contrast-enhanced computed tomography scan prior to and 2 weeks after the operation. Complete blood count and liver function tests were examined prior to and following the surgery, and complications and changes in the blood tests were monitored for 6 months. Over this period of investigation, the splenic volume was reduced by a mean value of 34.0%. The levels of serum alanine aminotransferase and aspartate aminotransferase were increased on the first day after the operation (P<0.05), although they recovered to the normal level within 1 week (P<0.05). The total level of bilirubin increased slightly, along with moderately decreased levels of albumin and cholinesterase on the first day, although these changes were not significant compared with the baseline (P>0.05). The white blood cell count was persistently significantly higher compared with the baseline over the course of the 6 months (P>0.05). The platelet count did not increase significantly for the first week after the operation (P>0.05); however, it was revealed to be significantly increased 1 month after the surgery (P<0.05). No significant complications were occurred during the follow-up period. In conclusion, hepatectomy combined with microwave ablation of the spleen was demonstrated to be a safe and effective procedure for patients with liver cancer and hypersplenism in the mid-term.

Effectiveness of ultrasound-guided percutaneous microwave ablation for symptomatic uterine fibroids: a multicentre study in China

PURPOSE

To evaluate the clinical efficacy of ultrasound-guided percutaneous microwave ablation (PMWA) therapy for symptomatic uterine fibroids in a multicentre study.

MATERIALS AND METHODS

Patients with symptomatic uterine fibroids who underwent PMWA at multiple treatment centres in China between January 2013 and August 2015 were prospectively studied to compare the reduction rate of uterine fibroids, haemoglobin level and uterine fibroid symptom and health-related quality of life questionnaire (UFS-QOL) scores before and at 3, 6 and 12 months after ablation.

RESULTS

A total of 311 patients (405 leiomyomas) from eight treatment centres underwent the treatment (age, 29-55 years; mean ± SD, 41 ± 5.11 years). The mean diameter of the myomas ranged from 2.03 to 12.50 cm (mean, 5.10 ± 1.28 cm) and the volume ranged from 4.40 to 1022.14 cm³ (mean, 95.01 ± 70.29 cm³). Forty-eight myomas were identified as FIGO type 1/2 fibroids, 256 as type 3/4 fibroids and 101 as type 5/6 fibroids. The mean ablation rate was 86.6% (54.0-100%). The mean reduction rate was 63.5%, 78.5% and 86.7% at 3, 6 and 12 months posttreatment, respectively. The haemoglobin level increased significantly from 88.84 ± 9.31 g/L before treatment to 107.14 ± 13.32, 116.05 ± 7.66 and 117.79 ± 6.51 g/L at 3, 6 and 12 months posttreatment, respectively (p = .000). The symptom severity score (SSS) and health-related quality of life (HRQL) scores were also significantly improved posttreatment compared with before treatment (p = .000).

CONCLUSION

PMWA is an effective, minimally invasive treatment for symptomatic leiomyomas that can significantly improve the quality of life of patients.

Partial splenic embolization of patients with hypersplenism by transradial or transfemoral approach: a prospective randomized controlled trial

BACKGROUND

Partial splenic artery embolization (PSE) is an effective treatment modality for patients with hypersplenism. It is less invasive and has a quicker recovery compared with surgical procedures. PSE is usually performed using a femoral artery approach that requires bedrest for a few hours, which is rarely the case for transradial PSE.

PURPOSE

To compare the transradial and transfemoral approaches for embolization of spleen in patients with hypersplenism.

MATERIAL AND METHODS

In all, 84 patients with hypersplenism who required PSE were recruited. They were randomly divided into two groups on the basis of the procedure followed: the transradial approach (R-PSE, n = 39) or transfemoral approach (F-PSE, n = 45). Technical success, puncture rate, total procedure time, X-ray exposure time, length of stay in hospital (LOS), and complications of the two groups were recorded.

RESULTS

The procedure time, X-ray exposure time, and LOS were found to be lower in the R-PSE group than in the F-PSE. However, this difference was not statistically significant.

CONCLUSION

The transradial artery approach for PSE in patients with hypersplenism is feasible with no major complications as compared to the femoral approach.

A Review of Therapeutic Ablation Modalities

Understanding basic science and technical aspects is essential for scientists and engineers to develop and enhance ablative modalities, and for clinicians to effectively apply therapeutic ablative techniques. An overview of ablative modalities, anatomical locations, and indications for which ablations are performed is presented. Specifically, basic concepts, parameter selection, and underlying biophysics of tissue injury of five currently used therapeutic ablative modalities are reviewed: radiofrequency ablation (RFA), cryoablation (CRA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), and chemical ablation (CHA) (ablative agents: acetic acid, ethanol, hypertonic sodium chloride, and urea). Each ablative modality could be refined for expanding applications, either independently or in combination, for future therapeutic use.

A Comparative Study of Surgical Splenectomy, Partial Splenic Embolization, and High-Intensity Focused Ultrasound for Hypersplenism

OBJECTIVES

This study compared splenectomy, partial splenic embolization, and high-intensity focused ultrasound (HIFU) therapy, which represent the traditional, mature, and newest methods for improving thrombocytopenia in hypersplenism, respectively.

METHODS

A total of 69 patients with hypersplenism were treated with surgical splenectomy (n = 31), HIFU (n = 26), or partial splenic embolization (n = 12). They were followed closely for at least 6 months, and the effectiveness of the treatments was compared.

RESULTS

Among the 3 groups, splenectomy was the most effective treatment for increasing peripheral blood cells. Embolization reduced the operating time and hospital stay, but HIFU was relatively safer and less invasive than the other treatments.

CONCLUSIONS

High-intensity focused ultrasound has wide clinical indications for hypersplenism and may be safer than other treatment methods. Therefore, it is a good alternative procedure for patients with a high surgical risk.

Percutaneous Microwave Ablation in the Spleen for Treatment of Hypersplenism in Cirrhosis Patients

AIM

The aim of this study was to estimate the feasibility and therapeutic effectiveness of percutaneous microwave ablation in the treatment of hypersplenism in cirrhosis.

METHODS

Forty-one cirrhosis patients with hypersplenism were treated with ultrasonography-guided percutaneous microwave ablation between February 2007 and August 2011. Peripheral blood cell counts, portal vein diameter, splenic vein diameter, and blood flow of splenic vein were evaluated before and after the operation, and complications of the treatment were also investigated. All patients were followed up for 24 months.

RESULTS

The levels of platelets and white blood cells were increased, while the splenic vein diameter narrowed gradually after the therapy and 24 months later. Moreover, patients received percutaneous microwave ablation had much lower splenic venous flow velocity. The portal vein diameter did not change significantly 6 months after the treatment, although it narrowed gradually within 3 months after the treatment. Furthermore, no complications such as uncontrollable bleeding, splenic abscess, spleen rupture, and damage in surrounding organ happened after the therapy.

CONCLUSIONS

Graded percutaneous microwave ablation, as a minimally invasive therapy, could damage the spleen, increase the levels of platelets and white blood cells, and reduce portal hypertension effectively without serious complications. Percutaneous microwave ablation is an effective, safe, and feasible method for cirrhosis patients with hypersplenism.

Radiofrequency ablation for treatment of hypersplenism: A feasible therapeutic option

We present a case of a patient with hypersplenism secondary to portal hypertension due to hepato-splenic schistosomiasis, which was accompanied by severe and refractory thrombocytopenia. We performed spleen ablation and measured the total spleen and ablated volumes with contrast-enhanced computed tomography and volumetry. No major complications occurred, thrombocytopenia was resolved, and platelet levels remained stable, which allowed for early treatment of the patient’s underlying disease. Previous work has shown that splenic radiofrequency ablation is an attractive alternative treatment for hypersplenism induced by liver cirrhosis. We aimed to contribute to the currently sparse literature evaluating the role of radiofrequency ablation (RFA) in the management of hypersplenism. We conclude that splenic RFA appears to be a viable and promising option for the treatment of hypersplenism.

Partial embolization as re-treatment of hypersplenism after unsuccessful splenic artery ligation

Ligation of splenic artery (LSA) is used for the treatment of liver cirrhosis with hypersplenism. However, hypersplenism is not significantly improved following LSA treatment in some cases, and there are few reports of retreatment of hypersplenism after LSA. We report the case of a 47-year-old man with liver cirrhosis and hypersplenism who underwent LSA treatment, but did not significantly improve. Laboratory tests revealed severe leukocytopenia and thrombocytopenia. Celiac computed tomography arteriogram and digital subtraction angiography revealed two compensatory arteries connected to the hilar splenic artery from the left gastro-epiploic artery and from the dorsal pancreatic artery. Partial splenic embolization (PSE) was performed through the compensatory arteries. As a result, the patient achieved partial splenic ischemic infarction, and white blood cell and platelet counts rose and remained in the normal range. PSE is an effective therapeutic modality for the retreatment of hypersplenism when other modalities have failed.

Comparison of 3D ultrasound and magnetic resonance imaging for microwave ablation in the canine splenomegaly model

PURPOSE

Microwave ablation is used for the treatment of hypersplenism. Image guidance and ablation volume assessment is important to ensure that the ablation is successful. The accuracy of 3D ultrasound (US) and magnetic resonance imaging (MRI) in determining the parameters for microwave ablation were compared in a canine splenomegaly model.

METHODS

Microwave ablation of the spleen was performed on 13 dogs with congestive splenomegaly. Several combinations of power output and ablation time were used: 60 W for 300 s, 50 W for 360 s and 40 W for 450 s. The ablation zone volume was measured by 3D US and 3D MRI immediately after microwave ablation, and at 1, 2 and 8 weeks thereafter.

RESULTS

Compared with 3D MRI, the ablation zone reconstruction rate was lower with 3D US (92 vs. 100%). However, there was no significant difference was found in the ablation volume calculated soon after the treatment and 1 week and 2 months later.

CONCLUSION

3D US may be useful for quantifying the volume of microwave ablation zones in the spleens of experimental animals and appears promising as an alterative modality to MRI for clinical examinations.

Low-dose splenic irradiation in symptomatic congestive splenomegaly: report of five cases with literature data

Background

To show effectiveness of low-dose splenic irradiation in symptomatic congestive splenomegaly.

Methods

Five patients were referred to our department for symptomatic congestive splenomegaly within three years. Primary diseases were autoimmune hepatitis with liver cirrhosis (n = 2), cystic fibrosis (n = 1), granulomatous liver disease (n = 1) and Werlhof disease with liver cirrhosis (n = 1). Mean age was 54 years (range: 36–67). Patients received splenic irradiation with a total dose of 3 Gy (single dose: 0.5 Gy). One patient was re-irradiated after long-term failure with the same treatment schedule.

Results

In four patients long term relief of splenic pain could be observed during the follow-up time of median 20 (range: 2–36) months. Four patients showed haematological response after irradiation with an increase of erythrocytes, leucocytes and/or platelets. A slightly decrease in spleen size was found in two patients.

Conclusions

Low-dose splenic irradiation in symptomatic congestive splenomegaly is feasible and perhaps as effective as in lympho-and myeloproliferative malignancies regarding pain relief and haematological response.

Efficacy of perioperative enteral nutrition in management of hepatocellular carcinoma with cirrhosis

AIM: To investigate the clinical effect of perioperative enteral nutrition in improving perioperative liver function and postoperative complications in patients with hepatocellular carcinoma and cirrhosis.

METHODS: Sixty-four liver cancer patients with cirrhosis were randomly divided into either a study group or a control group. The control group received conventional treatment, and the study received additional enteral nutrition therapy on the basis of conventional treatment. The liver function, immune status and nutritional status were compared between the two groups to evaluate the clinical efficacy of enteral nutrition therapy.

RESULTS: The liver function indices on preoperative day 1 and postoperative days 1, 3 and 7 were significantly better in the study group than in the control group (ALT: 51.17 μmol/L ± 8.47 μmol/L vs 61.43 μmol/L ± 22.43 μmol/L, 104.42 μmol/L ± 48.25 μmol/L vs 167.43 μmol/L ± 78.35 μmol/L, 74.36 μmol/L ± 17.64 μmol/L vs 84.57 μmol/L ± 44.24 μmol/L, 63.93 μmol/L ± 7.32 μmol/L vs 79.28 μmol/L ± 11.73 μmol/L; AST: 31.36 μmol/L ± 18.37 μmol/L vs 47.48 μmol/L ± 11.57 μmol/L, 103.12 μmol/L ± 21.61 μmol/L vs 170.21 μmol/L ± 42.56 μmol/L, 84.26 μmol/L ± 11.53 μmol/L vs 127.25 μmol/L ± 31.14 μmol/L, 51.43 μmol/L ± 11.32 μmol/L vs 92.41 μmol/L ± 18.18 μmol/L, all P < 0.05). The immune indices and nutritional status indices s on preoperative day 1 and postoperative days 1, 7 and 10 day were also significantly better in the study group than in the control group (all P < 0.05). The incidence of complications in the study group was significantly lower than that in the control group, and no nutrition-related serious adverse reactions were observed.

CONCLUSION: Perioperative enteral nutrition can improve liver function and immunity and reduce the incidence of complications in patients with hepatocellular carcinoma and cirrhosis.

Experimental studies and clinical experiences on treatment of secondary hypersplenism with extracorporeal high-intensity focused ultrasound

The aim of this study is to investigate the efficacy and safety of extracorporeal high-intensity focused ultrasound (HIFU) in treatment of hypersplenism. Fifteen adult dogs, weighing 13-18 kg were divided into three groups: sham group, SVL group undergoing splenic vein ligation (SVL) after laparotomy, and SVL + HIFU group receiving SVL followed by extracorporeal HIFU. Pathologic and hematologic analyses were performed. We also reviewed the clinical data of 19 patients with secondary hypersplenism caused by liver cirrhosis or hepatocellular carcinoma who underwent extracorporeal HIFU. Extracorporeal HIFU significantly diminished the volume of the spleen of animals, coupled with occurrence of coagulation necrosis and fibrosis in the target area. Both platelet and red blood cell counts were significantly restored by HIFU intervention. Similarly, HIFU treatment improved the hematologic parameters in patients with hypersplenism, and no major complications were encountered. Extracorporeal HIFU intervention is effective and safe in managing secondary hypersplenism.

Ultrasound-guided microwave ablation for abdominal wall metastatic tumors: a preliminary study

AIM

To evaluate the feasibility, safety and efficacy of ultrasound-guided microwave (MW) ablation for abdominal wall metastatic tumors.

METHODS

From August 2007 to December 2010, a total of 11 patients with 23 abdominal wall nodules (diameter 2.59 cm ± 1.11 cm, range 1.3 cm to 5.0 cm) were treated with MW ablation. One antenna was inserted into the center of tumors less than 1.7 cm, and multiple antennae were inserted simultaneously into tumors 1.7 cm or larger. A 21 gauge thermocouple was inserted near important organs which required protection (such as bowel or gallbladder) for real-time temperature monitoring during MW ablation. Treatment outcome was observed by contrast-enhanced ultrasound and magnetic resonance imaging (MRI) [or computed tomography (CT)] during follow-up.

RESULTS

MW ablation was well tolerated by all patients. Six patients with 11 nodules had 1 thermocouple inserted near important organs for real-time temperature monitoring and the maximum temperature was 56 °C. Major complications included mild pain (54.5%), post-ablation fever (100%) and abdominal wall edema (25%). All 23 tumors (100%) in this group were completely ablated, and no residual tumor or local recurrence was observed at a median follow-up of 13 mo (range 1 to 32 mo). The ablation zone was well defined on contrast-enhanced imaging (contrast-enhanced CT, MRI and/or contrast-enhanced ultrasound) and gradually shrank with time.

CONCLUSION

Ultrasound-guided MW ablation may be a feasible, safe and effective treatment for abdominal wall metastatic tumors in selected patients.

Ultrasound-guided percutaneous microwave ablation of benign thyroid nodules: experimental and clinical studies

PURPOSE

To obtain the treatment parameters of internally cooled microwave antenna and to evaluate the feasibility of ultrasound-guided percutaneous microwave ablation (MWA) for benign thyroid nodules.

MATERIALS AND METHODS

MWAs were performed by microwave antenna (16G) in ex vivo porcine liver. The lesion diameters achieved in different groups (20, 25, and 30 W for 3, 5, 7, 10, and 12 min) were compared. The clinical study was approved by the ethics committee. Written informed consent was obtained from all patients. MWA was performed in 11 patients (male to female ratio=1:10; mean age, 50±7 years) with 11 benign thyroid nodules. Ultrasound scan, laboratory data, and clinical symptoms were evaluated before and 1 day and 1, 3, 6, 9, and 12 months after the procedure.

RESULTS

In ex vivo study, the ablation lesion at 30 W 12 min tended to have appropriate scope and spherical shape. In clinical study, the follow-up periods ranged from 1 to 9 months. At the last follow-up, the largest diameter decreased from 2.9±1.0 (range, 1.6-4.1) to 1.9±0.7 (range, 0.4-3.0) cm (P<0.01), and the volume decreased from 5.30±4.88 (range, 0.89-14.81) to 2.40±2.06 (range, 0.02-6.35) ml (P<0.01). The volume reduction ratio was 45.99±29.90 (range, 10.56-98.15) %. The cosmetic grading score was reduced from 3.20±0.79 to 2.30±0.95 (P<0.05). One patient experienced temporary nerve palsy and was recovered within 2 months after treatment.

CONCLUSION

The internally cooled microwave antenna can yield ideal ablation lesions, and ultrasound-guided percutaneous MWA is a feasible technique for benign thyroid nodules.

[Microwave tumor ablation. New devices, new applications?]

CLINICAL ISSUE

The majority of patients with hepatic malignancies are not amenable to surgical resection. In some of these cases minimally invasive ablative therapies are a treatment option.

STANDARD TREATMENT

Besides radiofrequency ablation, the most common ablative therapies are cryoablation, laser ablation and microwave ablation.

TREATMENT INNOVATIONS

The classic fields of application of microwave ablation are the treatment of malignancies of the liver, kidneys and lungs. Furthermore, cases of treatment of bone tumors and tumors of the adrenal gland have been reported as well as treatment of secondary hypersplenism.

PERFORMANCE

The manufacturers of microwave systems pursue different strategies to reach an optimal ablation zone, such as water or gas cooling of the antenna, the simultaneous use of different antennas or an automatic modulation of the microwave energy and frequency.

ACHIEVEMENTS

In contrast to other tumor ablation methods microwave ablation causes a direct heating of a tissue volume, thus this method is less vulnerable to the cooling effect of vessels in the ablation zone. Moreover the electric conductivity of the treated tissue does not influence microwave radiation so that microwave ablation has advantages for the treatment of high-resistance organs, such as the lungs or bone. Some publications have shown that microwave ablation causes larger ablation zones in less time in comparison to radiofrequency ablation.

PRACTICAL RECOMMENDATIONS

Classic indications for microwave ablation are the treatment of malignancies of the liver, lungs and kidneys. Initial technical problems have been solved, so that an increasing significance of the microwave ablation among the ablative therapies is to be expected.