Liver resection using a saline-linked radiofrequency dissecting sealer for transection of the liver

Experimental and numerical investigation of waterjet interaction with liver in connection with surgical technique

Hepatectomy, or liver resection, is a process by which through surgery part or all of the liver is removed. In this operation, less bleeding, negligible damage and fast removal are the most important requirements. Surgery through waterjet is one of the most efficient techniques which is widely used in hepatectomy. Some clinical studies are conducted to investigate waterjet method in liver resection. In the present study interaction of waterjet with liver during the process of the surgery is investigated in terms of mechanical engineering. For this purpose, a system of waterjet is designed to consider the interaction of waterjet with liver at different nozzle diameter and velocities. For validation, SPH-FEM model is used to analyze waterjet interaction with hyperelastic liver. In this model, liver cutting is simulated using element deletion defined by a subroutine code based on maximum principal strain criterion. Depth of cut along with degraded volume are measured experimentally and compared with simulated method. Results show that good agreement exists between experimental and simulation finding. By comparing depth of cut in the experimental and simulation results, it can be seen that liver behavior changes from brittle to ductile by increasing waterjet velocity during the experimental tests. For the simulation, maximum principal strain threshold is set to be between 0.1 and 0.4. However, the best agreement between experimental and simulation results exists at maximum principal strain threshold equal to 0.2. The findings can help surgeons to find the best working range of waterjet device and the most efficient operation.

Novel Hemostatic Technique During Laparoscopic Liver Parenchymal Transection: Saline-Linked Electrocautery Combined With Wet Oxidized Cellulose (SLiC-WOC) Method

Introduction: Although laparoscopic hepatectomy has the potential advantage of reducing intraoperative blood loss, it is more difficult to control bleeding laparoscopically compared to an open approach. We introduced a novel hemostatic technique, the saline-linked electrocautery combined with wet oxidized cellulose (SLiC-WOC) method, during laparoscopic hepatectomy where a combination of saline-linked electrocautery (SLiC) and wet oxidized cellulose (WOC) is used. This study aimed to investigate the feasibility of employing the SLiC-WOC method for laparoscopic hepatectomy.

Methods: Thirteen patients who underwent laparoscopic liver resection with the SLiC-WOC method between 2019 and 2020 were included in this study. The number of bleeding episodes in which the SLiC-WOC method was applied was counted, and the time required to achieve complete hemostasis was measured.

Results: Among the bleeding events that were difficult to achieve hemostasis by SLiC alone, 94% were safely and efficiently controlled. Additionally, 69% of hemostasis was achieved within 60 seconds and 91% within 120 seconds. Postoperatively, most patients experienced no complications and no operative mortality was observed.

Conclusions: The SLiC-WOC method can provide safe and time-efficient hemostasis during laparoscopic hepatectomy. This is especially crucial for bleeding, which is difficult to control using electrocautery alone.

[Blood-saving technologies in extensive liver resections]

The researches devoted to blood-saving technologies in extensive liver resections are analyzed in the manuscript. Resection of three and more liver segments is effective method of surgical treatment of various focal liver lesions. Surgical (anatomical resection with hilar glissonean access, Pringle maneuver, modern technical equipment, etc.), anesthesiological (reduction of central venous pressure, hemostatic agents) and transfusion (autologous blood donation, transfusion, cell saver, etc.) methods contribute to prevention and reduction of blood loss. Intraoperative measures for blood loss prevention should include adequate surgical incision and liver mobilization, precise techniques of parenchymal dissection (for example, cavitation surgical aspirator-destructor), use of clip applicators and local or systemic hemostatic agents.

Efficacy of a Laparoscopic Saline-Coupled Bipolar Sealer in Minimally Invasive Hepatobiliary Surgery

Hepatic resection presents unique surgical challenges to reduce blood loss during parenchymal division. The development of saline-coupled bipolar devices, in which hemostasis is achieved at lower temperatures than electrocautery or other bipolar sealing devices, have been employed for open hepatic resection. Saline-coupled bipolar devices have now become available for minimally invasive use. The goals of this study were to evaluate the feasibility and safety of a laparoscopic saline-coupled bipolar device for minimally invasive hepatectomy. Seventeen patients (median age 66 years, range 36-81) were consented for inclusion and enrolled. Patient demographics, intraoperative data, and surgeon feedback were collected. Seven robot-assisted partial hepatectomies, 9 laparoscopic partial hepatectomies, and 1 laparoscopic cholecystectomy with liver abscess resection were performed. Average operating time was 222 ± 33 minutes (median 188 minutes; range 61-564 minutes) with no difference between robotic versus laparoscopic time. Successful seals were achieved in all cases following application of 150 to 200 J energy (average 179 ± 3 J, average time to achieve a successful seal 9.3 ± 2.7 minutes). Estimated blood loss was 362 ± 74 mL (median 300 mL, range 5-1200 mL) and 3/17 patients received intraoperative blood transfusion. No bile leaks were detected in any of the patients. Median length of stay was 5 days (range 1-20 days), and there were no readmissions within 30 days. Postoperative morbidity occurred in 5/17 patients, all of which were Clavien Grade 1. There was no mortality within 90 days or complications requiring a return to the operating room, and there were no liver-specific morbidities. These data suggest the laparoscopic Aquamantys device represents a useful device for use in minimally invasive liver resection.

Efficacy of high-intensity focused ultrasound-assisted hepatic resection (HIFU-AR) on blood loss reduction in patients with liver metastases requiring hepatectomy: study protocol for a randomized controlled trial

BACKGROUND

Liver resection is the only potentially curative treatment for colorectal liver metastases (LM). It is considered a safe procedure, but is often associated with blood loss during liver transection. Blood transfusions are frequently needed, but they are associated with increased morbidity and risk of recurrence. Many surgical devices have been developed to decrease blood loss. However, none of them has proven superior to the standard crushing technique. We developed a new, powerful intra-operative high-intensity focused ultrasound (HIFU) transducer which destroys tissue by coagulative necrosis. We aim to evaluate whether HIFU-assisted liver resection (HIFU-AR) results in reduced blood loss.

METHODS

This is a prospective, single-centre, randomized (1:1 ratio), comparative, open-label phase II study. Patients with LM requiring a hepatectomy for ≥ 2 segments will be included. Patients with cirrhosis or sinusoidal obstruction syndrome with portal hypertension will be excluded. The primary endpoint is normalized blood loss in millilitres per square centimetre of liver section plane. Secondary endpoints are: total blood loss, transection time, transection time per square centimetre of liver area, haemostasis time, clip density on the liver section area, rate and duration of the Pringle manœuvre, rate of patients needing a blood transfusion, length of hospital stay, morbidity, patients with positive resection margin, and local recurrence. Assuming a blood loss of 7.6 ± 3.7 mL/cm² among controls, the study will have 85% power to detect a twofold decrease of blood loss in the experimental arm, using a Wilcoxon (Mann-Whitney) rank-sum test with a 0.05 two-sided significance level. Twenty-one randomized patients per arm are required. Considering the risk of contraindications at surgery, up to eight patients may be enrolled in addition to the 42 planned, with an enrolment period of 24 months. Randomization will be stratified by surgeon.

DISCUSSION

We previously demonstrated the safety and efficacy of intra-operative HIFU in patients operated on for LM. We also demonstrated the efficacy of HIFU-AR in a preclinical study. Participants in the HIFU-AR group of this randomized trial can expect to benefit from reduced blood loss and decreased ischemia of liver parenchyma.

TRIAL REGISTRATION

Clinicaltrial.gov, NCT02728167 . Registered on 22 March 2016.

Expert opinion on advanced techniques for hemostasis in liver surgery

BACKGROUND

Reduction of perioperative blood loss and intraoperative transfusion are two major factors associated with improving outcomes in liver surgery. There is currently no consensus as to the best technique to achieve this.

METHODS

An international Panel of Experts (EP), made up of hepatobiliary surgeons from well-known high-volume centres was assembled to share their experience with regard to the management of blood loss during liver resection surgery. The process included: a review of the current literature by the panel, a face-to-face meeting and an on-line survey completed by the EP prior to and following the face-to-face meeting, based on predetermined case scenarios. During the meeting the most frequently researched surgical techniques were appraised by the EP in terms of intraoperative blood loss.

RESULTS

All EP members agreed that high quality research on the subject was lacking. Following an agreed risk stratification algorithm, the EP concurred with the existing research that a haemostatic device should always be used along with any user preferred surgical instrumentation in both open and laparoscopic liver resection procedures, independently from stratification of bleeding risk. The combined use of Ultrasonic Dissector (UD) and saline-coupled bipolar sealing device (Aquamantys(®)) was the EP preferred technique for both open and laparoscopic surgery.

CONCLUSIONS

This EP propose the use of a bipolar sealer and UD for the best resection technique and essential equipment to minimise blood loss during liver surgery, stratified according to transfusion risk, in both open and laparoscopic liver resection.

Symptomatic Perihepatic Fluid Collections After Hepatic Resection in the Modern Era

BACKGROUND

Improvements in liver surgery have led to decreased mortality rates. Symptomatic perihepatic collections (SPHCs) requiring percutaneous drainage remain a significant source of morbidity.

STUDY DESIGN

A single institution's prospectively maintained hepatic resection database was reviewed to identify patients who underwent hepatectomy between January 2004 and February 2012.

RESULTS

Data from 2173 hepatectomies performed in 2040 patients were reviewed. Overall, 200 (9%) patients developed an SPHC, the majority non-bilious (75.5%) and infected (54%). Major hepatic resections, larger than median blood loss (≥360 ml), use of surgical drains, and simultaneous performance of a colorectal procedure were associated with an SPHC on multivariate analysis. Non-bilious, non-infected (NBNI) collections were associated with lower white blood cell (WBC) counts, absence of a bilio-enteric anastomosis, use of hepatic arterial infusion pump (HAIP), and presence of metastatic disease, and resolved more frequently with a single interventional radiology (IR) procedure (85 vs. 46.5%, p < 0.001) more quickly (15 vs. 30 days, p = 0.001).

CONCLUSIONS

SPHCs developed in 9% of patients in a modern series of hepatic resections, and in one third were non-bilious and non-infected. In the era of modern interventional radiology, the need for re-operation for SPHC is exceedingly rare. A significant proportion of minimally symptomatic SPHC patients may not require drainage, and strategies to avoid unnecessary drainage are warranted.

Evaluation of a newly developed piezo actuator-driven pulsed water jet system for liver resection in a surviving swine animal model

Background

Preservation of the hepatic vessels while dividing the parenchyma is key to achieving safe liver resection in a timely manner. In this study, we assessed the feasibility of a newly developed, piezo actuator-driven pulsed water jet (ADPJ) for liver resection in a surviving swine model.

Methods

Ten domestic pigs underwent liver resection. Parenchymal transection and vessel skeletonization were performed using the ADPJ (group A, n = 5) or an ultrasonic aspirator (group U, n = 5). The water jet was applied at a frequency of 400 Hz and a driving voltage of 80 V. Physiological saline was supplied at a flow rate of 7 ml/min. After 7 days, the animals were killed and their short-term complications were examined and compared between the two groups.

Results

No significant complications, such as massive bleeding, occurred in either group during the surgical procedures. The transection time per transection area was significantly shorter in group A than in group U (1.5 ± 0.3 vs. 2.3 ± 0.5 min/cm², respectively, P = 0.03). Blood loss per transection area was not significantly different between groups A and U (9.3 ± 4.2 vs. 11.7 ± 2.3 ml/cm², P = 0.6). All pigs in group A survived for 7 days. No postoperative bleeding or bile leakage was observed in any animal at necropsy.

Conclusion

The present results suggested that the ADPJ reduces transection time without increasing blood loss. ADPJ is a safe and feasible device for liver parenchymal transection.

Opportunistic use of a Foley catheter to provide a common electrocautery with a water-irrigating channel for hepatic parenchymal transection

High-tech surgical energy devices that are used during a single surgery have increased in number and the expense for such disposable units is by no means negligible. We developed a handmade water-irrigating monopolar electrocautery using a Foley catheter to perform liver parenchymal transection. A commonly used 20-24 Fr Foley catheter was cut at a length of about 8 cm. The shaft of the 5 mm ball electrode measuring 13.5 cm in length was then inlaid into the urine drainage channel. The target tissues were cauterized without making an eschar, thereby preventing the adhesion of the electrode to the tissues. A ball electrode with our handmade water irrigation sheath can be made in only a few minutes at a very low cost, using common medical supplies and yielding satisfactory effects comparable to the use of specialized high-tech devices.

Computer modeling and ex vivo experiments with a (saline-linked) irrigated electrode for RF-assisted heating

BACKGROUND

Externally irrigated radiofrequency (RF) electrodes have been widely used to thermally ablate tumors in surface tissue and to thermally coagulate the transection plane during a surgical resection. As far as we know, no mathematical model has yet been developed to study the electrical and thermal performance of these electrodes, especially the role of the saline layer that forms around the electrode.

METHODS

Numerical models of a TissueLink device model DS3.0 (Salient Surgical Technologies, Portsmouth, NH, USA) were developed. Irrigation was modeled including a saline layer and a heat convection term in the governing equation. Ex vivo experiments based on fragments of bovine hepatic tissue were conducted to obtain information which was used in building the numerical model. We compared the 60°C isotherm of the computer results with the whitening contour in the heated samples.

RESULTS

Computer and experimental results were in fine agreement in terms of lesion depth (2.4 mm in the simulations and 2.4 ± 0.6 mm in the experiments). In contrast, the lesion width was greater in the simulation (9.6 mm vs. 7.8 ± 1.8 mm). The computer simulations allowed us to explain the role of the saline layer in creating the thermal lesion. Impedance gradually decreased as heating proceeded. The saline was not observed to boil. In the proximity of the electrode (around 1 mm) the thermal lesion was mainly created by the RF power in this zone, while at a further distance the thermal lesion was created by the hot saline on the tissue surface by simple thermal conduction. Including the heat convection term associated with the saline velocity in the governing equation was crucial to verifying that the saline layer had not reached boiling temperature.

CONCLUSIONS

The model reproduced thermal performance during heating in terms of lesion depth, and provided an explanation for: 1) the relationship between impedance, electrode insertion depth, and saline layer, and 2) the process of creating thermal lesions in the tissue with this type of electrode.

Complications following hepatectomy

As the number of liver resections in the United States has increased, operations are more commonly performed on older patients with multiple comorbidities. The advent of effective chemotherapy and techniques such as portal vein embolization, have compounded the number of increasingly complex resections taking up to 75% of healthy livers. Four potentially devastating complications of liver resection include postoperative hemorrhage, venous thromboembolism, bile leak, and post-hepatectomy liver failure. The risk factors and management of these complications are herein explored, stressing the importance of identifying preoperative factors that can decrease the risk for these potentially fatal complications.

Radiofrequency bipolar hemostatic sealer reduces blood loss, transfusion requirements, and cost for patients undergoing multilevel spinal fusion surgery: a case control study

Background

A relatively new method of electrocautery, the radiofrequency bipolar hemostatic sealer (RBHS), uses saline-cooled delivery of energy, which seals blood vessels rather than burning them. We assessed the benefits of RBHS as a blood conservation strategy in adult patients undergoing multilevel spinal fusion surgery.

Methods

In a retrospective cohort study, we compared blood utilization in 36 patients undergoing multilevel spinal fusion surgery with RBHS (Aquamantys®, Medtronic, Minneapolis, MN, USA) to that of a historical control group (n = 38) matched for variables related to blood loss. Transfusion-related costs were calculated by two methods.

Results

Patient characteristics in the two groups were similar. Intraoperatively, blood loss was 55% less in the RBHS group than in the control group (810 ± 530 vs. 1,800 ± 1,600 mL; p = 0.002), and over the entire hospital stay, red cell utilization was 51% less (2.4 ± 3.4 vs. 4.9 ± 4.5 units/patient; p = 0.01) and plasma use was 56% less (1.1 ± 2.4 vs. 2.5 ± 3.4 units/patient; p = 0.03) in the RBHS group. Platelet use was 0.1 ± 0.5 and 0.3 ± 0.6 units/patient in the RBHS and control groups, respectively (p = 0.07). The perioperative decrease in hemoglobin was less in the RBHS group than in the control group (−2.0 ± 2.2 vs. –3.2 ± 2.1 g/dL; p = 0.04), and hemoglobin at discharge was higher in the RBHS group (10.5 ± 1.4 vs. 9.7 ± 0.9 g/dL; p = 0.01). The estimated transfusion-related cost savings were $745/case by acquisition cost and approximately 3- to 5-fold this amount by activity-based cost.

Conclusions

The use of RBHS in patients undergoing multilevel spine fusion surgery can conserve blood, promote higher hemoglobin levels, and reduce transfusion-related costs.

Liver resection using cavitron ultrasonic surgical aspirator (CUSA) versus harmonic scalpel: a retrospective cohort study

BACKGROUND

The aim of this study was to evaluate the safety and efficacy of two device combinations used in parenchymal division during hepatic resections in non-cirrhotic patients and without inflow vascular occlusion.

METHODS

We retrospectively analyzed 47 patients who underwent liver resection at our Institution from 2004 to 2010 using the TissueLink with either the Cavitron Ultrasonic Surgical Aspirator (CUSA) or the Harmonic Scalpel. The TissueLink was used with the CUSA in 27 patients and with the Harmonic Scalpel in 20 patients.

RESULTS

Median estimated blood loss (EBL) in the Harmonic Scalpel and CUSA groups was 250 and 1035 mL respectively (p < 0.05). Three patients were transfused banked blood perioperatively in the Harmonic Scalpel group and 11 in the CUSA group (p < 0.05). Median operative time in the Harmonic Scalpel and CUSA groups was 185 and 290 min respectively. Length of stay (LOS) was shorter in the Harmonic Scalpel group at 6 days compared to 7 days in the CUSA group (p < 0.05). Perioperative complications were documented in 20% and 26% in the Harmonic Scalpel and CUSA groups, respectively.

CONCLUSIONS

Our results show the Harmonic Scalpel with TissueLink to be a safe, effective method of parenchymal division with significantly less EBL and LOS when compared to CUSA with TissueLink.

A prospective randomized controlled trial of hemostasis with a bipolar sealer during hepatic transection for liver resection

BACKGROUND

Excessive intraoperative blood loss and the possible requirement for blood transfusion are major problems in hepatic resection for liver tumors. The decrease of blood loss is a goal in liver surgery, and several technical developments have been introduced for this purpose. The aim of this prospective randomized study was to compare the use of the Cavitron Ultrasonic Surgical Aspirator (CUSA) with a radiofrequency-based bipolar hemostatic sealer versus CUSA with standard bipolar cautery (BC) in patients undergoing hepatic resection.

METHODS

One hundred nine patients with liver tumors were randomized to undergo hepatic transection via CUSA with a bipolar sealer (Aquamantys 2.3 Bipolar Sealer; n = 55) or BC (n = 54). Blood loss during parenchymal transection and speed of transection were the primary end points, whereas the degree of postoperative liver injury and morbidity were secondary end points.

RESULTS

Compared with the BC group, the bipolar sealer showed lesser blood loss during transection and blood loss divided by resection area (P = .0079 and .0008, respectively), shorter transection time (P = .0025), faster speed of transection (P < .0001), and fewer ties and ties divided by resection area required during transection (P < .0001).

CONCLUSION

CUSA with a bipolar sealer is superior to CUSA with standard BC for various hepatectomy in terms of less blood loss and faster speed of transection, with no increase in morbidity.

A hybrid method of laparoscopic-assisted open liver resection through a short upper midline laparotomy can be applied for all types of hepatectomies

BACKGROUND

Although hepatectomy procedures should be designed to provide both curability and safety, minimal invasiveness also should be pursued.

METHODS

We analyzed the data related to our method for laparoscopy-assisted open resections (hybrid method) through a short upper midline incision for various types of hepatectomies. Of 215 hepatectomies performed at Nagasaki University Hospital between November 2009 and June 2012, 102 hepatectomies were performed using hybrid methods.

RESULTS

A hybrid method was applicable for right trisectionectomy in 1, right hemihepatectomy in 32, left hemihepatectomy in 29, right posterior sectionectomy in 7, right anterior sectionectomy in 1, left lateral sectionectomy in 2, and segmentectomy in 7 patients, and for a minor liver resection in 35 patients (12 combined resections). The median duration of surgery was 366.5 min (range 149-709) min, and the median duration of the laparoscopic procedure was 32 min (range 18-77) min. The median blood loss was 645 g (range 50-5,370) g. Twelve patients (12 %) developed postoperative complications, including bile leakage in three patients, wound infections in two patients, ileus in two patients, and portal venous thrombus, persistent hyperbilirubinemia, incisional hernia, local liver infarction each in one patient. There were no perioperative deaths.

CONCLUSIONS

Our method of hybrid hepatectomy through a short upper midline incision is considered to be applicable for all types of hepatectomy and is a reasonable approach with no abdominal muscle disruption, which provides safe management of the hepatic vein and parenchymal resection even for patients with bilobular disease.

Technology-Assisted Versus Clamp-Crush Liver Resection

Objective. To review the published evidence on technology-assisted liver resection regarding operative time, intraoperative bleeding, mortality, hospital stay, postoperative bile leak, and other outcomes. Method. A systematic review of clinical studies comparing liver resection using vessel sealing systems (VSSs—LigaSure), Cavitron Ultrasonic Surgical Aspirator (CUSA), or radiofrequency dissecting sealer (RFDS) with the conventional clamp-crushing technique (CC) was performed. Data for each modality were synthesized and individually compared with CC with the methodology of meta-analysis. Result. In all, 8 randomized controlled trials (RCTs) and 7 nonrandomized studies evaluating 1539 patients were included. Compared with CC, the VSS group (3 RCTs and 3 nonrandomized studies) had significantly lower blood loss by a mean of 109 mL (weighted mean difference [WMD] = −109; 95% confidence interval [CI] = −192, −26; data on 494 patients), lower risk for postoperative bile leak by 63% (odds ratio [OR] = 0.37; CI = 0.17, 0.78; 559 patients), and shorter total hospital stay by 2 days (WMD = −2.04; CI = −3.08, −1; 340 patients); no difference was noted for liver parenchyma transection time and mortality. No difference was noted between CUSA (4 RCTs and 1 nonrandomized study) or RFDS (3 RCTs and 3 nonrandomized studies) versus CC for any of the studied outcomes. Conclusion. Of the 3 modalities used in liver resection (VSS, CUSA, and RFDS), only VSS appeared to offer significant benefit over standard CC. However, the generalization of our findings is limited by the scarcity and clinical heterogeneity of the published studies. Large, well-designed and implemented RCTs are warranted to further investigate the usefulness of novel modalities used in liver resection.

Comparison of liver parenchymal ablation and tissue necrosis in a cadaveric bovine model using the Harmonic Scalpel, the LigaSure, the Cavitron Ultrasonic Surgical Aspirator and the Aquamantys devices

OBJECTIVES

The amount of tissue that is ablated or necrosed at the line of parenchymal transection is of clinical significance in the interpretation of resection margin status following hepatic resection. The aim of this study was to define the extent of parenchymal ablation and necrosis in liver tissue using the Harmonic Scalpel, the LigaSure, the Cavitron Ultrasonic Surgical Aspirator (CUSA) and the Aquamantys dissector ex vivo.

METHODS

Mounted blocks of non-perfused bovine liver were transected using the Harmonic Scalpel, LigaSure, CUSA and Aquamantys devices. Outcome measures included parenchymal ablation (ablation band widths and weights) and tissue necrosis band widths along the line of transection. Each experiment was replicated five times.

RESULTS

All devices were associated with parenchymal ablation (Harmonic Scalpel, 4.73 ± 1.62 mm; LigaSure, 4.55 ± 2.02 mm; CUSA, 7.16 ± 2.87 mm; Aquamantys, 4.75 ± 1.43 mm) and tissue necrosis (Harmonic Scalpel, 1.07 ± 0.46 mm; LigaSure, 1.36 ± 0.36 mm; CUSA, 0.81 ± 0.21 mm; Aquamantys, 0.81 ± 0.36 mm).

CONCLUSIONS

The Harmonic Scalpel, LigaSure, CUSA and Aquamantys devices were associated with bands of tissue loss along the hepatic parenchymal transection line in this benchtop cadaveric model. This should be taken into account in the interpretation of resection margin status following liver resection.

A Microwave Surface Applicator for Tissue Coagulation: Technical Characteristics and Performances

This work describes the mechanical and the electromagnetic design of a microwave surface applicator used to coagulate liver tissue in the treatment of hepatic tumors. A good prediction of the ratio between reflected and forward microwave power (return loss) is obtained with a finite element model using commercial software. Laboratory testing of the applicator performed in polyacrylamide gel (PAG) and in ex vivo bovine liver show a hemispherical heat distribution pattern and hemispherical ablations up to 20 mm in diameter and 15 mm in depth in a controlled manner in 1 min. The applicator can also be used to coagulate larger areas of tissue with 2–5 mm depth by moving the applicator on the surface of the tissue. Experimental results indicate that the coagulated volume of tissue is approximately proportional to the energy delivered into ex vivo bovine liver, hemispherical in shape, obtained in short time duration with a volumetric rate of coagulated tissue of about 50 mm3/s.

Low-dose steroid pretreatment ameliorates the transient impairment of liver regeneration

AIM

To determine if liver regeneration (LR) could be disturbed following radiofrequency (RF) ablation and whether modification of LR by steroid administration occurs.

METHODS

Sham operation, partial hepatectomy (PH), and partial hepatectomy with radiofrequency ablation (PHA) were performed on adult Fisher 344 rats. We investigated the recovery of liver volume, DNA synthetic activities, serum cytokine/chemokine levels and signal transducers and activators of transcription 3 DNA-binding activities in the nucleus after the operations. Additionally, the effects of steroid (dexamethasone) pretreatment in the PH group (S-PH) and the PHA group (S-PHA) were compared.

RESULTS

The LR after PHA was impaired, with high serum cytokine/chemokine induction compared to PH, although the ratio of the residual liver weight to body weight was not significantly different. Steroid pretreatment disturbed LR in the S-PH group. On the other hand, low-dose steroid pretreatment improved LR and suppressed tumor necrosis factor (TNF)-α elevation in the S-PHA group, with recovery of STAT3 DNA-binding activity. On the other hand, low-dose steroid pretreatment improved LR and suppressed TNF-α elevation in the S-PHA group, with recovery of STAT3 DNA-binding activity.

CONCLUSION

LR is disturbed after RF ablation, with high serum cytokine/chemokine induction. Low-dose steroid administration can improve LR after RF ablation with TNF-α suppression.

High-intensity focused ultrasound (HIFU)-assisted hepatic resection in an animal model

BACKGROUND

Bleeding is the main cause of postoperative complications of hepatic surgery. To minimize intraoperative bleeding during hepatectomy, resections are generally carried out under hepatic vascular control despite the risk of liver dysfunction in patients with chronic liver disease. This study evaluates the feasibility and safety of high-intensity focused ultrasound (HIFU)-assisted hepatic resection during an open procedure in an animal model.

METHODS

Three groups of 12-14-week-old Landrace pigs (n = 7/group) were used to evaluate HIFU-assisted liver resection (group A) vs liver resection with or without portal triad clamping (groups B and C). In each pig, liver resection was performed on the right and left paramedian lobes. The following were evaluated and compared in the 3 groups: total blood loss, blood loss/cm(2) of resection area, clip density, procedure duration, morbidity, and mortality.

RESULTS

Median blood loss was significantly lower in group A than in group B (P = .02), and group C (P = .007). Median blood loss/cm(2) of resection area was 4.77 mL/cm² in group A, 11.35 mL/cm² in group B, 12.22 mL/cm² in Group C. Precoagulation resulted in sealing blood vessels <5 mm; therefore, median clip density during liver transection was 0.78 clip/cm² in group A, 1.61 clip/cm(2) in group B, and 1.57 clip/cm(2) in group C. Median duration of the surgical procedure was 12 min in group A, 21 min in group B, and 19 min in group C.

CONCLUSIONS

HIFU-assisted hepatic resection during an open procedure in an animal model is safe, reduces bleeding, and allows real-time ultrasound guidance.

Hemi-hepatectomy in pediatric patients using two-surgeon technique and a liver hanging maneuver

AIM: To evaluate the efficacy of the two-surgeon technique with the liver hanging maneuver (LHM) for hepatectomies in pediatric patients with hepatoblastoma.

METHODS: Three pediatric patients with hepatoblastoma were enrolled in this study. Two underwent right hemi-hepatectomies and one underwent a left hemi-hepatectomy using the two-surgeon technique by means of saline-linked electric cautery (SLC) and the Cavitron Ultrasonic Surgical Aspirator (CUSA; Valleylab, Boulder, CO) and the LHM.

RESULTS: The mean operative time during the parenchymal transections was 50 min and the mean blood loss was 235 g. There was no bile leakage from the cut surface after surgery. No macroscopic or microscopic-positive margins were observed in the hepatic transections.

CONCLUSION: The two-surgeon technique using SLC and CUSA with the LHM is applicable to even pediatric patients with hepatoblastoma.

Hemostasis of the liver, spleen, and bone achieved by electrocautery greased with lidocaine gel

Despite advances in surgical techniques, achieving hemostasis of the liver, spleen, and bone during major surgery, especially after trauma, is still difficult. I describe a new procedure my colleagues and I devised to achieve parenchymatous hemostasis using electrocautery greased with lidocaine gel. After achieving good results in experimental studies and obtaining approval from our ethics committee, we used electrocautery greased with lidocaine gel for hemostasis in the following 36 procedures: multisegmental hepatectomy to remove hepatic tumors (n = 6); partial hepatectomy to allow hepatojejunostomy for intrahepatic biliary obstruction (n = 10); laparoscopic liver biopsy (n = 4); subtotal splenectomy (n = 8; for portal hypertension in 5 patients, splenic ischemia in 2, and Gaucher's disease in 1); laparoscopic splenic biopsy (n = 1); and bone resection (n = 7; as pelvic-femoral resection in 6 patients and to remove a rectal tumor invading the coccyx in 1). This procedure was easy to perform and achieved complete hemostasis of the minor blood vessels in all patients. No postoperative bleeding occurred and the follow-up course was satisfactory. Electrocautery greased with lidocaine gel is an inexpensive, readily available, and efficient method to achieve hemostasis of minor vessels in hepatic, splenic, and bone operations.

Milestones in the evolution of hepatic surgery

This paper describes the rapid evolution of modern liver surgery, starting in the middle of the twentieth century. Claude Couinaud studied and described the segmental anatomy of the liver, Thomas Starzl performed the first liver transplantations, and Henri Bismuth introduced the concept of anatomical resections. Hepatic surgery has developed significantly since those early days. To date, innovative techniques are applied, using cutting-edge technologies: Intraoperative ultrasound, techniques of vascular exclusion of the liver, new devices for performing homeostasis and dissection, laparoscopy for resections, and new drugs that allow the resection of previously unresectable tumors. The next stage in liver surgery will probably be the implementation of a multidisciplinary holistic approach to the liver-diseased patient that will ensure the best and most efficient treatments in the future.

Liver Resection Using a Four-Prong Radiofrequency Transection Device

Multiple techniques are available for division of hepatic parenchyma. This is the largest United States report examining the use of the Habib 4X tissue coagulator (AngioDynamics, Queensbury, NY). The objective was to collect standard parameters associated with successful, benchmarked liver surgery outcomes using this new device, and in particular, examine the risk of margin failure. Ninety-four consecutive operations using the Habib 4X were analyzed with special attention to local failure at resection margin, blood loss/transfusion, and operative times. An institutional review board approved protocol allowed collection and analysis of demographic information and outcomes for intraoperative, perioperative, and long term follow-up. Eighteen patients had biopsy only. Thirty-one had lobar resections and 46 had wedge or segmental resections. There were 30 primary hepatic and 46 metastatic tumor diagnoses. There were a total of 33 (43%) recurrences with a mean time to recurrence of 212 days (range 15-974). Of the 27 intrahepatic recurrences, four (15%) were at the margin. The OR time ranged from 115 to 642 minutes (average 283 min). The average recorded blood loss was 427 mL; 11 patients were transfused (average 0.43 units). The Habib 4X is a safe tool to use when evaluating the parameters of blood loss, transfusion, and margin recurrence.

Randomized clinical trial of efficacy and costs of three dissection devices in liver resection

BACKGROUND

In recent decades a variety of instruments for liver dissection has become available. This randomized controlled trial analysed the efficacy and costs of three different liver dissection devices.

METHODS

Ninety-six patients without cirrhosis undergoing liver resection were randomized to either ultrasonic dissection, waterjet dissection or dissecting sealer (32 in each group). Patients were unaware of the device used. The primary endpoint was dissection speed. Secondary endpoints were intraoperative blood loss, morbidity and mortality, and costs of dissection devices, staplers and haemostatic agents.

RESULTS

Dissection was slower with the dissecting sealer (P = 0.004 versus waterjet dissector). The difference was more pronounced for extended resections (mean(s.e.m.) 1.62(0.36) cm(2)/min versus 3.42(0.53) and 3.63(0.51) cm(2)/min for ultrasonic and water dissectors respectively; P = 0.037). Costs were significantly higher for the dissecting sealer when atypical or segmental resections were performed. Four patients died after extended resections; postoperative complications did not differ between groups.

CONCLUSION

The dissecting sealer is slower than the ultrasonic dissector or water dissector. The three devices are equally safe in terms of blood loss, transfusions and postoperative complications. Ultrasonic and water dissectors might be more favourable economically than the dissecting sealer.

REGISTRATION NUMBER

ISRCTN52294555 (http://www.controlled-trials.com).

Clamp-crush technique vs. radiofrequency-assisted liver resection for primary and metastatic liver neoplasms

BACKGROUND

Several techniques for liver resection have been developed. We compared radiofrequency-assisted (RF) and clamp-crush (CC) liver resection (LR) in terms of blood loss, operating time and short-term outcomes in primary and metastatic tumour resection.

METHODS

From 2002 to 2007, 196 consecutive patients with primary or metastatic hepatic tumours underwent RF-LR (n= 109; group 1) or CC-LR (n= 87; group 2) in our unit. Primary endpoints were intraoperative blood loss (and blood transfusion requirements) and total operative time. Secondary endpoints included postoperative complications, mortality and intensive care unit (ICU) and hospital stay. Data were collected retrospectively on all patients with primary or secondary liver lesions.

RESULTS

Blood loss was similar (P= 0.09) between the two groups of patients with the exception of high MELD score (>9) cirrhotic patients, in whom blood loss was lower when RF-LR was used (P < 0.001). Total operative time and transection time were shorter in the CC-LR group (P= 0.04 and P= 0.01, respectively), except for high MELD score (>9) cirrhotic patients, in whom total operation and transection times were shorter when RF-LR was used (P= 0.04). Rates of bile leak and abdominal abscess formation were higher after RF-LR (P= 0.04 for both).

CONCLUSIONS

Clamp-crush LR is reliable and results in the same amount of blood loss and a shorter operating time compared with RF-LR. Radiofrequency-assisted LR is a unique, simple and safe method of resection, which may be indicated in cirrhotic patients with high MELD scores.

Research and development of a new RF-assisted device for bloodless rapid transection of the liver: computational modeling and in vivo experiments

Background

Efficient and safe transection of biological tissue in liver surgery is strongly dependent on the ability to address both parenchymal division and hemostasis simultaneously. In addition to the conventional clamp crushing or finger fracture methods other techniques based on radiofrequency (RF) currents have been extensively employed to reduce intraoperative blood loss. In this paper we present our broad research plan for a new RF-assisted device for bloodless, rapid resection of the liver.

Methods

Our research plan includes computer modeling and in vivo studies. Computer modeling was based on the Finite Element Method (FEM) and allowed us to estimate the distribution of electrical power deposited in the tissue, along with assessing the effect of the characteristics of the device on the temperature profiles. Studies based on in vivo pig liver models provided a comparison of the performance of the new device with other techniques (saline-linked technology) currently employed in clinical practice. Finally, the plan includes a pilot clinical trial, in which both the new device and the accessory equipment are seen to comply with all safety requirements.

Results

The FEM results showed a high electrical gradient around the tip of the blade, responsible for the maximal increase of temperature at that point, where temperature reached 100°C in only 3.85 s. Other hot points with lower temperatures were located at the proximal edge of the device. Additional simulations with an electrically insulated blade produced more uniform and larger lesions (assessed as the 55°C isotherm) than the electrically conducting blade. The in vivo study, in turn, showed greater transection speed (3 ± 0 and 3 ± 1 cm²/min for the new device in the open and laparoscopic approaches respectively) and also lower blood loss (70 ± 74 and 26 ± 34 mL) during transection of the liver, as compared to saline-linked technology (2 ± 1 cm²/min with P = 0.002, and 527 ± 273 mL with P = 0.001).

Conclusion

A new RF-assisted device for bloodless, rapid liver resection was designed, built and tested. The results demonstrate the potential advantages of this device over others currently employed.

Two different methods for donor hepatic transection: cavitron ultrasonic surgical aspirator with bipolar cautery versus cavitron ultrasonic surgical aspirator with radiofrequency coagulator-A randomized controlled trial

The aim of this study was to compare the Cavitron ultrasonic surgical aspirator (CUSA) with bipolar cautery (BP) to CUSA with a radiofrequency coagulator [TissueLink (TL)] in terms of efficacy and safety for hepatic transection in living donor liver transplantation. Twenty-four living liver donors (n = 12 for each group) were randomized to undergo hepatic transection using CUSA with BP or CUSA with TL. Blood loss during parenchymal transection and speed of transection were the primary endpoints, whereas the degree of postoperative liver injury and morbidity were secondary endpoints. Median blood loss during liver transection was significantly lower in the TL group than in the BP group (195.2 +/- 84.5 versus 343.3 +/- 198.4 mL; P = 0.023), and liver transection was significantly faster in the TL group than in the BP group (0.7 +/- 0.2 versus 0.5 +/- 0.2 cm(2)/minute; P = 0.048). Significantly fewer ties were required during liver transection in the TL group than in the BP group (15.8 +/- 4.8 versus 22.8 +/- 7.9 ties; P = 0.023). The morbidity rates were similar for the 2 groups. In conclusion, CUSA with TL is superior to CUSA with BP for donor hepatectomy in terms of blood loss and speed of transection with no increase in morbidity.

A clinical comparative analysis of crush/clamp, stapler, and dissecting sealer hepatic transection methods

INTRODUCTION

Several methods for hepatic parenchymal division exist. The primary aim was to assess differences in postoperative bile leaks, operative blood loss, and margin status between three transection methods: crush/clamp (CC), stapler (SP), or dissecting sealer (DS).

METHODS

A single institution, retrospective cohort study was performed on data collected over a three-year period in patients undergoing elective liver resection using the CC, SP, or DS. Patients were excluded if multiple methods of transection were used or for intraoperative death. The association of bile leak with transection type was assessed. A logistic regression model was tested to assess if blood loss was associated with the covariates of transection method, use of portal inflow occlusion, extent of liver resection, and other concurrent major operations.

RESULTS

Analyses included 141 patients. The stapler method was quicker than the other methods (p=0.01). The risk of postoperative bile leak was no different between CC, SP, and DS transection methods (p=0.23). There was no difference in mean blood loss or transfusions; however, hepatectomies performed with DS were associated with an increased risk of blood loss > or = 1000 mL compared to CC (p=0.04). There were no differences in mean surgical margin between the three methods.

CONCLUSION

The risk of bile leaks was not different between the three methods. While mean blood loss was similar, hepatectomy performed with the DS was associated with an increased risk of having operative blood loss > or = 1000 mL compared to CC. Margins were equal by all methods. The stapler method was quicker.

Long-term outcome of hepatocellular carcinoma patients who underwent liver resection using microwave tissue coagulation

BACKGROUND/AIMS

Our policy for the surgical treatment of hepatocellular carcinoma (HCC) has been to minimize the extent of liver resection using a microwave tissue coagulator (MTC) and to not perform Pringle's maneuver for the prevention of ischemic injury to the liver routinely. We verify the safety of liver resection using MTC in HCC patients with poor liver functional reserve, and clarify the long-term outcome of HCC patients who underwent curative resection using MTC.

METHODOLOGY

One hundred sixty-eight patients who underwent curative resection using MTC between 1992 and 2001 were divided into two groups according each patient's score in the Indocyanin Green Retension 15 Test (ICG-R15 test). The high (ICG-R15 values>20) and low ICG-R15 groups (ICG-R15 values<20) included 100 and 68 HCC patients, respectively. Clinical characteristics of each group were evaluated, and operative mortality and morbidity, as well as overall and disease-free survival rates, were compared between the two groups to determine risk factors for overall and disease-free survival.

RESULTS

Although there were significant differences in liver function-related parameters between the low and high ICG-R15 groups, no differences in surgical or tumor factors were found. No patients in this study developed post-operative liver failure, and there was no significant difference in morbidity between the low and high ICG-R15 groups. The overall survival rate of the low ICG-R15 group was significantly longer than the high ICG-R15 group (p=0.0003). Cox's multivariate analysis showed that an ICG-R15 value less than 20 was the only significant independent factor for overall survival. Disease-free survival rates in the low ICG-R15 group were significantly longer than in the high ICG-R15 group (p=0.0007). Multivariate analysis showed that serum albumin level and number of tumors were significant independent factors for disease-free survival.

CONCLUSION

The long-term outcome of HCC patients with low ICG-R15 following curative resection using MTC was acceptable. This procedure was safe even for patients with high ICG-R15.

Open hepatic parenchymal transection using ultrasonic dissection and bipolar coagulation

Liver transection is the most challenging part of liver resection due to the risk of massive blood loss which is associated with increased postoperative morbidity and mortality, as well as reduced long-term survival after resection of malignancies. Among the devices used for open parenchyma transection, ultrasonic dissection with bipolar cautery forceps is one of the most widely used technique worldwide. We identified four retrospective comparative studies and three randomized controlled trials dealing with the efficacy of ultrasonic dissector (UD) compared with other techniques including the historical clamp crushing technique. UD is associated with similar blood loss and slower resection time compared with water-jet or clamp crushing technique. However, it seems to be more precise in dissecting vessels. Its use does not impact on morbidity and hospital stay compared with other techniques. From an economic point of view, UD is the most expensive technique and may be a disadvantage for low centre volume. UD with bipolar cautery is one of the safest and the most efficient device for liver transection, even if its superiority over the clamp crushing technique has not been well established. It is considered as a standard technique for liver transection.

Two-surgeon technique using saline-linked electric cautery and ultrasonic surgical aspirator in living donor hepatectomy: its safety and efficacy

BACKGROUND

Saline-linked electric cautery (SLC) is introduced as an effective device to reduce blood loss in liver surgery. The aim of the current study was to evaluate the safety and efficacy of a 2-surgeon technique using SLC and the Cavitron Ultrasonic Surgical Aspirator (CUSA; Valleylab, Boulder, CO) in living donor hepatectomy.

METHODS

Forty-three living donor right hepatectomy cases were enrolled in this study. The first 28 cases underwent liver transection with CUSA alone (CUSA group), while additional SLC was applied in the current 15 cases (2-surgeon technique, TS group).

RESULTS

Blood loss was significantly reduced by the 2-surgeon technique (1,115.2 +/- 652.9 g in CUSA group vs 732.3 +/- 363.6 g in TS group, P < .05). In the TS group, there was no bile leakage from the cut surface. The early graft function and postoperative recipient survival were not significantly different between the groups.

CONCLUSIONS

According to our single-center experience, blood loss and donor complications in living donor hepatectomies were significantly reduced using a 2-surgeon technique using CUSA and SLC, while maintaining the graft viability.

A radiofrequency-assisted device for bloodless rapid transection of the liver: A comparative study in a pig liver model

BACKGROUND

Efficient and safe liver parenchymal transection is dependent on the ability to address both parenchymal division and hemostasis simultaneously. In this article we describe and compare with a saline-linked instrument a new radiofrequency (RF)-assisted device specifically designed for tissue thermocoagulation and division of the liver used on an in vivo pig liver model.

METHODS

In total, 20 partial hepatectomies were performed on pigs through laparotomy. Two groups were studied: group A (n=8) with hepatectomy performed using only the proposed RF-assisted device and group B (n=8) with hepatectomy performed using only a saline-linked device. Main outcome measures were: transection time, blood loss during transection, transection area, transection speed and blood loss per transection area. Secondary measures were: risk of biliary leakage, tissue coagulation depth and the need for hemostatic stitches. Tissue viability was evaluated in selected samples by staining of tissue NADH.

RESULTS

In group A both blood loss and blood loss per transection area were lower (p=0.001) than in group B (70+/-74 ml and 2+/-2 ml/cm(2) vs. 527+/-273 ml and 13+/-6 ml/cm(2), for groups A and B, respectively). An increase in mean transection speed when using the proposed device over the saline-linked device group was also demonstrated (3+/-0 and 2+/-1cm(2)/min for group A and B, respectively) (p=0.002). Tissue coagulation depth was greater (p=0.005) in group A than in group B (6+/-2 mm and 3+/-1 mm, for groups A and B, respectively). Neither macroscopic nor microscopic differences were encountered in transection surfaces between both groups.

CONCLUSIONS

The proposed RF-assisted device was shown to address parenchymal division and hemostasis simultaneously, with less blood loss and faster transection time than saline-linked technology in this experimental model.

The use of saline-linked radiofrequency dissecting sealer for liver transection in patients with cirrhosis

BACKGROUND

In patients with cirrhosis excessive hemorrhage and the need for blood transfusion are associated with increased postoperative morbidity and mortality as well as a poor long-term outcome. Saline-linked radiofrequency dissecting sealer (TissueLink) is a recent advance in technology that improves hemostasis during difficult liver resections. Preliminary studies have shown that this technique reduces blood loss without inflow occlusion.

PATIENTS AND METHODS

A controlled study was performed on 122 consecutive patients with cirrhosis who underwent liver resection for hepatocytotic carcinoma. The outcomes of liver transection with clamp crushing and TissueLink were compared to evaluate which strategy is most beneficial to the patients.

RESULTS

Both intraoperative blood loss and blood transfusion requirements were significantly higher in the crushing clamp group than in the TissueLink group (P = 0.047 and P = 0.031, respectively). In addition, a significantly higher number of patients required a blood transfusion in the crushing clamp group (P < 0.001). However, the transection time was significantly faster in the crushing clamp group than in the TissueLink group (P < 0.001). The number of patients that required Pringle's maneuver was markedly higher in the crushing clamp group (P < 0.001). In addition, the hemostasis time was significantly longer in the crushing clamp group (P < 0.001). The serum aspartate aminotransferase levels 3 and 7 days after surgery were significantly higher in the crushing clamp group than in the TissueLink group (P = 0.035 and P = 0.003, respectively). Serum total bilirubin levels were markedly increased 3 days after surgery in the crushing clamp group than in the TissueLink group (P = 0.011). Biliary leakage occurred in a higher number of crushing clamp patients (six) than TissueLink patients (three), although this difference was not significant. The operative morbidity not including biliary leakage was higher in the crushing clamp group than the TissueLink group (nine patients versus five patients, respectively).

CONCLUSION

This study reveals that the TissueLink procedure has beneficial effects during liver transection under cirrhotic conditions in terms of blood loss and reperfusion-related liver injury. However, this procedure requires a significantly longer transection time of the parenchyma.

Heat-zone effect after surface application of dissecting sealer on the "in situ margin" after tumorectomy for liver tumors

BACKGROUND

Resection remains the gold standard in the treatment of liver tumors. But radiofrequency ablation allows destruction of small liver tumors. The aim of this study was to evaluate the effect of surface application of a saline-linked dissecting sealer (TL) on the tumor bed that might contain residual microscopic tumor cells after resection (in situ margin).

STUDY DESIGN

Five hepatitis-infected woodchucks bearing primary liver tumors were used. Tumors > 1 cm in diameter were removed by tumorectomy. Alternately, the in situ margins were treated or not by TL. All samples were frozen and stained with hematoxylin and eosin and nicotine adenine dinucleotide (cell viability test). The median tumor diameter was 22 mm (range 10 to 53 mm). Among 84 in situ retrieved samples, 50 were from TL-treated tumors and 34 were from untreated controls.

RESULTS

The mean (+/-SD) heat-zone area was 12.6+/-2.8 mm in TL-treated tumors and 0.6+/-0.7 mm in controls (p < 0.001). Hematoxylin and eosin and nicotine adenine dinucleotide analyses showed 70% to 98% of cell destruction inside the heat-zone area in the TL-treated samples. There were macroscopic residual tumor cells (R2 resection) in 53 samples, with a median length of tumoral tissue inside the in situ margin of 3.5 mm. Among them, the heat-zone area was considerably longer in TL-treated versus untreated controls (13.3+/-2.6 mm versus 0.7+/-0.9 mm, p < 0.001). In samples with no residual tumor cells or microscopic residual tumor cells (R0/R1; n=31), the length of the tumoral margin was similar between TL-treated and untreated controls (0.7+/-0.2 mm and 0.9+/-0.2 mm, respectively, p=NS). Compared with controls, no viable cell was visible (up to 5 mm of depth) in the in situ margins in the TL-treated samples (p < 0.05).

CONCLUSIONS

These results support the hypothesis that surface application of the TL device on the in situ margins after tumorectomy could induce a substantial heat-zone area ranging from 10 to 13 mm, inside which, on a regressive heat gradient, up to 98% of cells could be destroyed. These observations could help to reduce marginal recurrence, especially in patients requiring multiple tumorectomies or complex liver resections for malignancy.

Resection of abdominal solid organs using high-intensity focused ultrasound

Our objective was to evaluate high-intensity focused ultrasound (HIFU) for minimizing blood loss during surgery by hemodynamically isolating large portions of solid organs before their resection. A high-power HIFU device (in situ intensity of 9000 W/cm(2), frequency of 3.3 MHz) was used to produce a wall of cautery for sealing of blood vessels along the resection line in surgically exposed solid organs (liver lobes, spleen and kidneys) of eight adult pigs. Following HIFU application, the distal portion of the organ was excised using a scalpel. If any blood vessels were still bleeding, additional HIFU application was used to stop the bleeding. The resection was achieved in 6.0 +/- 1.5 min (liver), 3.6 +/- 1.1 min (spleen) and 2.8 +/- 0.6 min (kidneys) of HIFU treatment time, with no occurrence of bleeding for up to 4 h (until sacrifice). The coagulated region at the resection line had average width of 3 cm and extended through the whole thickness of the organ (up to 4 cm). Blood vessels of up to 1 cm in size were occluded. This method holds promise for future clinical applications in resection of solid tumors and hemorrhage control from high-grade organ injuries.

Decreasing pancreatic leak after distal pancreatectomy: saline-coupled radiofrequency ablation in a porcine model

Despite marked improvements in pancreatic surgery, the high incidence and morbidity of pancreatic leak after resection has remained unchanged. The objective of this study was to evaluate the role of saline-coupled radiofrequency ablation (TissueLink) as an alternative to traditional methods of stump closure in an animal model of distal pancreatectomy. Forty swine were randomized after pancreatic transection and remnant stump was either oversewn in a traditional fashion (control) or treated with the device alone (TissueLink). Animals were killed and necropsied at 3 or 5 weeks postoperatively. Primary endpoints were the development of a pancreatic fistula defined as dye extravasation from the remnant duct, presence of undrained amylase-rich fluid collections/abscess, and greater than threefold drain/serum amylase after the third postoperative day. The incidence of pancreatic leak in the TissueLink group was 5.5 vs 42% in the control group (p = 0.01). There were no differences in operative time or other clinical parameters measured. Histologic analysis of the remnant pancreatic stumps confirmed our results. These data support our hypothesis that saline-coupled radiofrequency ablation leads to obliteration of ducts with a resultant decrease in pancreatic leak and subsequent complications. This technology may play a substantial role in preventing this dreaded complication in the clinical setting.

Current role of bloodless liver resection

Liver resections are demanding operations which can have life threatening complications although they are performed by experienced liver surgeons. Recently new technologies are applied in the field of liver surgery, having one goal: safer and easier liver operations. The aim of this article is to address the issue of bloodless liver resection using radiofrequency energy. Radionics, Cool-tip^TM System and Tissue Link are some of the devices which are using radiofrequency energy. All information included in this article, refers to these devices in which we have personal experience in our unit of liver surgery. These devices take advantage of its unique combination of radiofrequency current and internal electrode cooling to perform sealing of the small vessels and biliary radicals. Dissection is also feasible with the cool-tip probe. For the purposes of this study patient sex, age, type of disease and type of surgical procedure in association with the duration of parenchymal transection, blood loss, length of hospital stay, morbidity and mortality were analyzed. Cool-tip RF device may provide a unique, simple and rather safe method of bloodless liver resections if used properly. It is indicated mostly in cirrhotic patients with challenging hepatectomies (segment VIII, central resections). The total operative time is eliminated and the average blood loss is significantly decreased. It is important to note that this technique should not be applied near the hilum or the vena cava to avoid damage of these structures.

Silkclasy: a simple way for liver transection during anatomic hepatectomies

BACKGROUND

Parenchymal transection is the most important step of liver resection, and during this phase, blood loss may lead to morbidity and mortality. Liver parenchyma can be transected by different ways such as finger fracture, clamp crushing, or instrument-based techniques.

METHODS

A simple and cost-efficient method has been developed for liver transection using a technique based on silk crushing of the liver substance.

RESULTS

We have successfully employed this technique in 278 consecutive liver resections from July 2001 to March 2006. The average duration of hepatic transection varied according to the type of liver resection: 22 min (range 15-42), 19 min (range 11-37), and 12 min (range 7-21) for right hepatectomy, left hepatectomy, and bisegmentectomy 2-3, respectively. The mean transection speed was 6.9 +/- 2.3 cm(2)/min. Blood transfusions were necessary in 42 patients (15.1%), and there were three operative deaths (1.1%). Morbidity rate was 20.9% (58 patients).

CONCLUSIONS

This technique allows a safe and quick liver transection without the use of expensive hemostatic devices, and also precludes the use of inflow occlusion maneuvers. We recommend the use of this technique in centers with low economic resources.

Current techniques of liver transection

The operative mortality rate of liver resection has decreased from 10% to 20% before the 1980s to <5% in most specialized hepatobiliary centers nowadays. The most important factor for better outcome is reduced blood loss due to improvement in surgical techniques. Liver transection is the most challenging part of liver resection, associated with a risk of massive hemorrhage. Understanding the segmental anatomy of the liver and delineation of the proper transection plane using intraoperative ultrasound are prerequisites to safe liver transection. Clamp crushing and ultrasonic dissection are the two most widely used transection techniques. In recent years, new instruments using different types of energy for coagulation or sealing of vessels have been developed for liver transection. These include radiofrequency devices, Harmonic Scalpel, Ligasure and TissueLink dissecting sealer. Whether these new instruments, used alone or in combination with clamp crushing or ultrasonic dissection, improve the safety of liver transection has not been clearly demonstrated. The use of the vascular stapler for transection of major intrahepatic vascular trunks is also gaining popularity. These new instruments are particularly useful in liver transection during laparoscopic liver resection. Adjunctive measures such as intermittent Pringle maneuver and low central venous pressure anesthesia are also useful measures to reduce the risk of hemorrhage. This article reviews the safety and efficacy of different techniques of liver transection, with particular attention to evidence from randomized controlled trials available in the literature.

How should transection of the liver be performed?: a prospective randomized study in 100 consecutive patients: comparing four different transection strategies

OBJECTIVE

To identify the most efficient parenchyma transection technique for liver resection using a prospective randomized protocol.

SUMMARY BACKGROUND DATA

Liver resection can be performed by different transection devices with or without inflow occlusion (Pringle maneuver). Only limited data are currently available on the best transection technique.

METHODS

A randomized controlled trial was performed in noncirrhotic and noncholestatic patients undergoing liver resection comparing the clamp crushing technique with Pringle maneuver versus CUSA versus Hydrojet versus dissecting sealer without Pringle maneuver (25 patients each group). Primary endpoints were intraoperative blood loss, resection time, and postoperative liver injury. Secondary end points included the use of inflow occlusion, postoperative complications, and costs.

RESULTS

The clamp crushing technique had the highest transection velocity (3.9 +/- 0.3 cm/min) and lowest blood loss (1.5 +/- 0.3 mL/cm) compared with CUSA (2.3 +/- 0.2 cm/min and 4 +/- 0.7 mL/cm), Hydrojet (2.4 +/- 0.3 cm/min and 3.5 +/- 0.5 mL/cm), and dissecting sealer (2.5 +/- 0.3 cm/min and 3.4 +/- 0.4 mL/cm) (velocity: P = 0.001; blood loss: P = 0.003). Clamp crushing technique was associated with the lowest need for postoperative blood transfusions. The degree of postoperative reperfusion injury and complications were not significantly different among the groups. The clamp crushing technique proved to be most cost-efficient device and had a cost-saving potential of 600 to 2400 per case.

CONCLUSIONS

The clamp crushing technique was the most efficient device in terms of resection time, blood loss, and blood transfusion frequency compared with CUSA, Hydrojet, and dissecting sealer, and proved to be also the most cost-efficient device.