Rapid microwave ablation of large hepatocellular carcinoma in a high-risk patient

Early experience with a new integrated microwave surgical device, Acrosurg Revo®, for laparoscopic surgery: A case series of two patients

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Early experience with Acrosurg Revo® in laparoscopic surgery has been described.

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Acrosurg Revo® does not cause sparks or tissue scattering.

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A clean surgical field can be maintained during surgery.

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The Acrosurg Revo®︎ may be a useful energy device for laparoscopic surgery.

Introduction

Abdominal surgery uses various energy devices for vessel sealing, tissue dissection, and detachment. Currently, Acrosurg Revo® (Nikkiso Co., Ltd., Tokyo, Japan), a novel energy device using microwaves, has been developed for use in laparoscopic surgery. This report describes the early clinical experience of using this device in two cases of laparoscopic surgery.

Presentation of case

Case 1 was of a 64-year-old woman who underwent laparoscopic abdominal incisional hernia repair. Case 2 was of a 56-year-old man with a diagnosis of ascending and sigmoid colon cancer who underwent laparoscopic right hemicolectomy and sigmoid colectomy with D3 dissection. Each surgery was completed using Acrosurg Revo® and an endoscopic electrosurgical unit. The postoperative course was uneventful, and both patients were discharged from the hospital without any complications.

Discussion

With this new and novel device, vessel sealing, hemostasis, coagulation, tissue dissection, and detachment were all possible. Notably, there was no spark or mist that hindered the surgical field of view. Furthermore, because microwave coagulation did not result in tissue carbonization, there was a considerable decrease in device tip contamination.

Conclusion

The Acrosurg Revo® may be a useful energy device for laparoscopic surgery.

Radiofrequency Ablation and Microwave Ablation in Liver Tumors: An Update

This article provides an overview of radiofrequency ablation (RFA) and microwave ablation (MWA) for treatment of primary liver tumors and hepatic metastasis. Only studies reporting RFA and MWA safety and efficacy on liver were retained. We found 40 clinical studies that satisfied the inclusion criteria. RFA has become an established treatment modality because of its efficacy, reproducibility, low complication rates, and availability. MWA has several advantages over RFA, which may make it more attractive to treat hepatic tumors. According to the literature, the overall survival, local recurrence, complication rates, disease-free survival, and mortality in patients with hepatocellular carcinoma (HCC) treated with RFA vary between 53.2 ± 3.0 months and 66 months, between 59.8% and 63.1%, between 2% and 10.5%, between 22.0 ± 2.6 months and 39 months, and between 0% and 1.2%, respectively. According to the literature, overall survival, local recurrence, complication rates, disease-free survival, and mortality in patients with HCC treated with MWA (compared with RFA) vary between 22 months for focal lesion >3 cm (vs. 21 months) and 50 months for focal lesion ≤3 cm (vs. 27 months), between 5% (vs. 46.6%) and 17.8% (vs. 18.2%), between 2.2% (vs. 0%) and 61.5% (vs. 45.4%), between 14 months (vs. 10.5 months) and 22 months (vs. no data reported), and between 0% (vs. 0%) and 15% (vs. 36%), respectively. According to the literature, the overall survival, local recurrence, complication rates, and mortality in liver metastases patients treated with RFA (vs. MWA) are not statistically different for both the survival times from primary tumor diagnosis and survival times from ablation, between 10% (vs. 6%) and 35.7% (vs. 39.6), between 1.1% (vs. 3.1%) and 24% (vs. 27%), and between 0% (vs. 0%) and 2% (vs. 0.3%). MWA should be considered the technique of choice in selected patients, when the tumor is ≥3 cm in diameter or is close to large vessels, independent of its size. IMPLICATIONS FOR PRACTICE: Although technical features of the radiofrequency ablation (RFA) and microwave ablation (MWA) are similar, the differences arise from the physical phenomenon used to generate heat. RFA has become an established treatment modality because of its efficacy, reproducibility, low complication rates, and availability. MWA has several advantages over RFA, which may make it more attractive than RFA to treat hepatic tumors. The benefits of MWA are an improved convection profile, higher constant intratumoral temperatures, faster ablation times, and the ability to use multiple probes to treat multiple lesions simultaneously. MWA should be considered the technique of choice when the tumor is ≥3 cm in diameter or is close to large vessels, independent of its size.

Renal effects of microwave ablation compared with radiofrequency, cryotherapy and surgical resection at different volumes of the liver treated

BACKGROUND

Renal changes after microwave tissue ablation (MTA) were compared with those following hepatic resection, cryotherapy (CRYO), and radiofrequency ablation (RFA). Structural damage producing renal impairment has been assessed directly by examining tissue specimens and by serum analysis for two sensitive biomarkers, retinol binding protein (RBP) and the heat shock protein 70 (HSP-70) for each modality at different ablation volumes.

METHODS

Live rats underwent MTA, surgical resection, CRYO or RFA of 15, 33 or 66% of total hepatic volume. Urine and tissue samples were collected at the time of death. Percentage of tubules with casts and glomerular damage, tissue expression of HSP-70 and urine RBP were evaluated and compared. Behaviour of the animals was also assessed by means of five different parameters and combined to produce a response score.

RESULTS

All RFA and CRYO rats undergoing 66% died and these animals had >60% of damaged tubuli and 8% of altered glomeruli. No animals treated by MTA or surgical resection died. Cut-off values (those predicting fatal treatments) could be identified for levels of HSP-70 and RBP.

CONCLUSIONS

Large volume MTA is associated with a significant reduced renal damage and is well tolerated compared with RFA and CRYO.

Lessons from laparoscopic liver surgery: a nine-year case series

Objective. This series describes a developing experience in laparoscopic liver surgery presenting results from 40 procedures including right hemihepatectomy, left lateral lobectomy, and microwave ablation therapy. Methods. Forty patients undergoing laparoscopic liver surgery between September 1997 and November 2006 were included. The data set includes: operative procedure and duration, intraoperative blood loss, conversion to open operation rates, length of hospital stay, complications, mortality, histology of lesions/resection margins, and disease recurrence. Results. Mean age of patient: 59 years, 17/40 male, 23/40 female, 23/40 of lesions were benign, and 17/40 malignant. Operations included: laparoscopic anatomical resections n = 15, nonanatomical resections n = 11, microwave ablations n = 8 and deroofing of cysts n = 7. Median anaesthetic time: 120 minutes (range 40–240), mean blood loss 78 mL and 1/40 conversions to open. Median resection margins were 10 mm (range 1–14) and median length of stay 3 days (range 1–10). Operative and 30-day mortality were zero with no local disease recurrence. Conclusion. Laparoscopic liver surgery appears safe and effective and is associated with reduced hospital stay. Larger studies are required to confirm it is oncologically sound.

Results of single-probe microwave ablation of metastatic liver cancer

AIMS

Microwave ablation (MWA) is the most recent development in the field of local ablative therapies. The aim of this study was to evaluate the variability and reproducibility of single-probe MWA vs. radiofrequency ablation (RFA) of liver metastases smaller than 3cm in patients without underlying liver disease.

METHODS

Sixteen liver metastases were treated using MWA, and matched for size and localisation with 13 metastases treated by RFA. Tumour diameters and postoperative ablation diameters were recorded (D1 transverse; D2 antero-posterior; D3 cranio-caudal; mm) on computed tomography scans.

RESULTS

Median D1, D2, and D3 ablation diameters after MWA vs. RFA were 18.5 (12-64) vs. 34 (16-41)mm (p=0.003), 26 (14-60) vs. 35 (28-40)mm (p=0.046), and 20 (10-73) vs. 32 (20-45)mm (p=0.025), respectively. As compared to RFA, the variability between the lesions after MWA was significantly higher for D2 (p<0.0001) and D3 (p=0.002) but not for D1 (p=0.15). The ablation diameters were less uniform after MWA than after RFA (p<0.001).

CONCLUSION

Ablation diameters after single-probe MWA of metastatic liver tumours are highly variable and suboptimal. Improvements are needed before MWA can be implemented routinely.

Ultrasound simulation of real-time temperature estimation during radiofrequency ablation using finite element models

Radiofrequency ablation is the most common minimally invasive therapy used in the United States to treat hepatocellular carcinoma and liver metastases. The ability to perform real-time temperature imaging while a patient is undergoing ablation therapy may help reduce the high recurrence rates following ablation therapy. Ultrasound echo signals undergo time shifts with increasing temperature due to sound speed and thermal expansion, which are tracked using both 1D cross correlation and 2D block matching based speckle tracking methods. In this paper, we present a quantitative evaluation of the accuracy and precision of temperature estimation using the above algorithms on both simulated and experimental data. A finite element analysis simulation of radiofrequency ablation of hepatic tissue was developed. Finite element analysis provides a method to obtain the exact temperature distribution along with a mapping of the tissue displacement due to thermal expansion. These local displacement maps were combined with the displacement due to speed of sound changes and utilized to generate ultrasound radiofrequency frames at specified time increments over the entire ablation procedure. These echo signals provide an ideal test-bed to evaluate the performance of both speckle tracking methods, since the estimated temperature results can be compared directly to the exact finite element solution. Our results indicate that the 1D cross-correlation (CC) method underestimates the cumulative displacement by 0.20mm, while the underestimation with 2D block matching (BM) is about 0.14 mm after 360 s of ablation. The 1D method also overestimates the size of the ablated region by 5.4% when compared to 2.4% with the 2D method after 720 s of ablation. Hence 2D block matching provides better tracking of temperature variations when compared to the 1D cross-correlation method over the entire duration of the ablation procedure. In addition, results obtained using 1D cross-correlation diverge from the ideal finite element results after 7 min of ablation and for temperatures greater than 65 degrees C. In a similar manner, experimental results presented using a tissue-mimicking phantom also demonstrate that the maximum percent difference with 2D block matching was 5%, when compared to 31% with the 1D method over the 700 s heating duration on the phantom.

Microwave ablation in a hepatic porcine model: correlation of CT and histopathologic findings

BACKGROUND

Thermal ablative techniques have gained increasing popularity in recent years as safe and effective options for patients with unresectable solid malignancies. Microwave ablation has emerged as a relatively new technique with the promise of larger and faster burns without some of the limitations of radiofrequency ablation (RFA). Here we study a new microwave ablation device in a living porcine model using gross, histologic, and radiographic analysis.

MATERIALS AND METHODS

The size and shape of ablated lesions were assessed using six pigs in a non-survival study. Liver tissue was ablated using 2, 4, and 8 min burns, in both peripheral and central locations, with and without vascular inflow occlusion. To characterize the post-ablation appearance, three additional pigs underwent several 4 min ablations each followed by serial computed tomography (CT) imaging at 7, 14, and 28 days postoperatively.

RESULTS

The 2 and 4 min ablations resulted in lesions that were similar in size, 33.5 cm(3) and 37.5 cm(3), respectively. Ablations lasting 8 min produced lesions that were significantly larger, 92.0 cm(3) on average. Proximity to hepatic vasculature and inflow occlusion did not significantly change lesion size or shape. In follow-up studies, CT imaging showed a gradual reduction in lesion volume over 28 days to 25-50% of the original volume.

DISCUSSION

Microwave ablation with a novel device results in consistently sized and shaped lesions. Importantly, we did not observe any significant heat-sink effect using this device, a major difference from RFA techniques. This system offers a viable alternative for creating fast, large ablation volumes for treatment in liver cancer.