Laparoscopic radiofrequency ablation of liver tumors: comparison of MR guidance versus conventional laparoscopic ultrasound for needle positioning in a phantom model

Generic surgical process model for minimally invasive liver treatment methods

Surgical process modelling is an innovative approach that aims to simplify the challenges involved in improving surgeries through quantitative analysis of a well-established model of surgical activities. In this paper, surgical process model strategies are applied for the analysis of different Minimally Invasive Liver Treatments (MILTs), including ablation and surgical resection of the liver lesions. Moreover, a generic surgical process model for these differences in MILTs is introduced. The generic surgical process model was established at three different granularity levels. The generic process model, encompassing thirteen phases, was verified against videos of MILT procedures and interviews with surgeons. The established model covers all the surgical and interventional activities and the connections between them and provides a foundation for extensive quantitative analysis and simulations of MILT procedures for improving computer-assisted surgery systems, surgeon training and evaluation, surgeon guidance and planning systems and evaluation of new technologies.

[Clinical application of laparoscopy-assisted and percutaneous radiofrequency ablation for hepatocellular carcinoma]

OBJECTIVE

To compared the efficacy of laparoscopy- assisted radiofrequency ablation (LRFA) and percutaneous radiofrequency ablation (PRFA) for the treatment of hepatocellular carcinoma (HCC).

METHODS

Between September, 2013 and September, 2016, a total of 60 HCC patients with 78 tumor nodules underwent LRFA (30 cases with 46 tumor nodules) and PRFA (30 cases with 32 tumor nodules) in our hospital. The patients were followed up for 3 years to compare the complete ablation rate, serious complications, recurrence rate and long-term survival rate between the two groups.

RESULTS

The patients receiving LRFA had a complete ablation rate of 95.65% (44/46), significantly higher than the rate of 93.75% (30/32) in PRFA group (P > 0.05). Significant differences were found between LRFA and PRFA groups in the incidence of serious complications [0 vs 6.7% (2/30), P < 0.05] and recurrence rate [13.33% (4/30) vs 23.33% (7/30), P < 0.05]. The 1-and 3-year overall survival rates of the patients were 96.15% and 55.12% in LRFA group and 93.73% and 48.54% in PRFA group, respectively (P > 0.05).

CONCLUSIONS

Both LRFA and PRFA are effective for HCC treatment, but is associated with a lower recurrence rate, fewer serious complications, a better treatment safety and a better applicability for tumor in difficult locations.

Advances in local ablation of malignant liver lesions

Local ablation of liver tumors matured during the recent years and is now proven to be an effective tool in the treatment of malignant liver lesions. Advances focus on the improvement of local tumor control by technical innovations, individual selection of imaging modalities, more accurate needle placement and the free choice of access to the liver. Considering data found in the current literature for conventional local ablative treatment strategies, virtually no single technology is able to demonstrate an unequivocal superiority. Hints at better performance of microwave compared to radiofrequency ablation regarding local tumor control, duration of the procedure and potentially achievable larger size of ablation areas favour the comparably more recent treatment modality; image fusion enables more patients to undergo ultrasound guided local ablation; magnetic resonance guidance may improve primary success rates in selected patients; navigation and robotics accelerate the needle placement and reduces deviation of needle positions; laparoscopic thermoablation results in larger ablation areas and therefore hypothetically better local tumor control under acceptable complication rates, but seems to be limited to patients with no, mild or moderate adhesions following earlier surgical procedures. Apart from that, most techniques appear technically feasible, albeit demanding. Which technology will in the long run become accepted, is subject to future work.

Postoperative immunosuppression after open and laparoscopic liver resection: assessment of cellular immune function and monocytic HLA-DR expression

In an experimental setting, the authors demonstrated a trend toward improved preservation of the immune system after laparoscopic hepatic resection compared with open surgery.

Background and Objectives:

Major abdominal procedures are strongly associated with postoperative immunosuppression and subsequent increased patient morbidity. It is believed that laparoscopic surgery causes less depletion of the systemic immune function because of the reduced tissue trauma. Various cytokines and monocytic HLA-DR expression have been successfully implemented to assess postoperative immune function. The aim of our study was to show the difference in immunologic profiles after minimally invasive versus conventional liver resection.

Methods:

Ten animals underwent either laparoscopic or conventional open left lateral liver resection. Flow cytometric characteristics of HLA-DR expression on monocytes and lipopolysaccharide-stimulated cellular secretion of tumor necrosis factor α, interferon γ, interleukin 6, and interleukin 8 were measured and analyzed in ex vivo whole blood samples. Intraoperative and postoperative clinical outcome parameters were also documented and evaluated.

Results:

All animals survived the procedures. Postoperative complications were fever (n = 3), wound infections (n = 2), and biloma (n = 1). Open surgery showed a morbidity rate of 80% compared with 40% after laparoscopic surgery. Laparoscopic liver resection showed no postoperative immunoparalysis. Major histocompatibility complex class II expression in this group was elevated, whereas the open surgery group showed decreased major histocompatibility complex class II expression on postoperative day 1. Postoperative secretion of tumor necrosis factor α, interleukin 6, and interferon γ was lower in the open surgery group. Elevated transaminase levels after laparoscopy might have resulted from an ischemia/reperfusion injury caused by the capnoperitoneum.

Conclusion:

Major immunoparalysis depression was not observed in either group. Laparoscopic surgery shows a tendency to improve immunologic recovery after liver resection.

Real-time monitoring of radiofrequency ablation and postablation assessment: accuracy of contrast-enhanced US in experimental rat liver model

PURPOSE

To examine the accuracy of the unenhanced zone at contrast material-enhanced ultrasonography (US) in predicting coagulative necrosis during and 21 days after radiofrequency (RF) ablation by using radiologic-pathologic comparison.

MATERIALS AND METHODS

Animal studies were approved by the Institutional Animal Care and Use Committee. The livers of 28 rats underwent US-guided RF ablation. In four animals, contrast-enhanced US was performed during ablation and 2 hours and 2, 7, 14, and 21 days after ablation. The unenhanced zone area on US images was measured. DiI-labeled microbubbles were administered during ablation at 2, 4, and 6 minutes or at 2 hours and 2, 7, 14, and 21 days after ablation in the remaining 24 animals (n = 3 at each time point). One minute later, the animal was euthanized, and the ablated liver was harvested. Tissue samples were imaged to quantify total fluorescence, and NADH staining was performed on the same slice. Hematoxylin-eosin staining was also performed. The findings on fluorescence images, NADH-stained images, and hematoxylin-eosin-stained images were compared. The areas of DiI bubble-negative zones, NADH-negative zones, and lightly NADH-staining zones were measured. Data were analyzed by using one-way analysis of variance.

RESULTS

The area of the unenhanced zone on contrast-enhanced US images increased during RF ablation and reached a maximum within 2 days after ablation. At histopathologic examination, a transition zone manifested adjacent to the coagulation zone until 2 days after ablation. The DiI-bubble negative zone on fluorescence images and the damaged zone (transition zone plus coagulation zone) on NADH-stained images increased rapidly within 2 hours after ablation, then slowly reached the maximum on day 2. The ratios of the mean areas of these two zones at hour 2 to those at day 2 were 94.6% and 95.6%, respectively. High uniformity between the damaged zone on NADH-stained images and the DiI bubble-negative zone on fluorescence images was noted at all time points.

CONCLUSION

The temporary transition zone in NADH staining is partially damaged and should transition to nonviability 2 days after ablation. These results demonstrate that contrast-enhanced US can help delineate the maximum area of cell damage (to within 5% of the maximum) as early as 2 hours after ablation. Contrast-enhanced US may be a simple and accurate tool for monitoring the effects of RF ablation and quantifying the size of thermal damage after treatment.