Liver resection by use of an incremental bipolar radiofrequency generator and six-needle in-line comb.

P. Rossi, A. De Majo, A. L. Gaspari

General Division, Tor Vergata University, Rome Tor Vergata Polyclinic, PTV Director Prof. A.L. Gaspari

Introduction

Progress in surgical techniques, in anaesthesia, better knowledge of anatomy and hepatic physiology allow, in expert hands, resectional surgery with low mortality and reduced morbidity. However, intra-operative blood loss remains the main problem, being associated with increased post-operative morbidity and reduced long-term survival (1,2). In order to reduce bleeding, many manoeuvres, have been perfected: Pringle, total vascular exclusion, reduction of central venous pressure (3,4,5). To the same end, many devices have been developed and many studies carried out with a view to comparing these with the standard kelly- clasia technique (clamp-crushing technique), with uneven results (6 – 16). In 2002, Habib described an innovative technique with monopolar radiofrequency (RF) to effect “wedge” resections with minimal blood loss (17). It consists of coagulating the hepatic parenchyma around the tumour with a “cooled-tip” monopolar needle so as to allow transection by common scalpel. Subsequently described in major resections (18), this technique is commonly indicated as “Radio-frequency assisted liver resection” (RFA-LR). After wide experience in the use of radiofrequency thermo-ablation of primitive and secondary liver tumours (19,20,21), we started an experimental study, in collaboration with engineers of the LED S.p.a. company (Aprilia, Roma), first on “ex vivo” pig liver and then on “in vivo” animals, that led to the realization of an innovative apparatus consisting of a incremental bipolar radiofrequency generator and six-needle in-line comb (22,23) . In this report we wish to explain the results of the use of this apparatus in the clinical setting in eleven patients, of which the first six made up a pilot study.

Materials and Methods

Generator

The apparatus, named Surtron SB, consists of a incremental bipolar radiofrequency generator and six-needle in-line comb (figure 1) with a frequency of 470 KHz, power 150 W, 160 1 volts that, through five bipolar circuits, simultaneously supplies a probe known as the comb (figure 2) consisting of six 1.5 mm diameter electrode needles spaced at 6 mm intervals. The energy to be delivered is automatically determined according to the tissue impedance between the two central electrodes and is correlated to the thickness of the liver. Each electrode is automatically switched out when the current reaches 50% of the previous maximum value and this corresponds to a valid coagulation of the parenchyma. This algorithm was studied experimentally in the “in vivo” animal model by means of correlation between the level of coagulation as evaluated by the surgeon and the current flow curve. The term incremental refers to the fact that the current flowing between two adjacent electrodes is not the sum, as in traditional apparatus, but the difference. Therefore, each electrode receives a higher voltage than the preceding electrode (incremental mode). The electrodes are coated with a layer of NbN and CrN in order to avoid adhesion of the coagulated tissue and thus easing removal of the comb. A special plastic device has been realized for protection of the surgeon and of surrounding organs during the introduction of the probe and the supply of power (figure 3).

Handpiece

2

Protection shield

Our technique consists of two parallel applications of the comb; the first (figure 4) determines a “slice” of coagulation about 1.2 mm width and alongside this, the second produces a further 6mm of necrosis (fig 5). The transection of the parenchyma is performed with a common scalpel along this second line and leaving in situ a portion of necrotic tissue about 1 cm thick (fig 6). We prefer to coagulate and section with the “step by step” technique rather than carry out the coagulation of the entire intended plane. During the transection, the separation of the edges and the blunt dissection manoeuvres allow, when necessary, isolation and closure of intra-parenchymal vascular structures by means of clips or ligatures.

3

First line of coagulation

4

Second line of coagulation

5

Parenchymal section

After approval by the Tor Vergata Polyclinic Ethical Committee, we realized a clinical pilot study in six patients, primarily with a view to evaluating safety and tolerability, and secondarily the efficacy of the thermo-coagulation of the liver parenchyma by means of our apparatus in liver resections for tumours. To that end we enlisted 6 patients affected by hepatic tumour suitable for resection. In each case we carried out careful exploration of the peritoneal cavity in order to exclude the presence of extra-hepatic involvement, local colonic recurrence and peritoneal carcinomatosis. The liver was mobilized in relation to the intervention to be carried out and underwent intra-operative ultrasonography (Hitachi H19 with EUP – 053T intra-operative probe) to confirm the lesions, their number, position, relationship with the principal vascular structures and the eventual presence of nodules not revealed by the pre-operative imaging. The safety and tolerability (primary aim) were investigated through the evaluation of: a) The post-operative coagulation parameters (TAP, PTT and D-Dimers); b) The blood flow of the glissonian vessels and hepatic veins using intra- and post- operative Echo-Colour-Doppler; c) Parameters of hepatic function; d) Cardio-respiratory monitoring. In order to study the efficacy (secondary aim), the following were evaluated: a) Intra-operative blood loss; b) correct cicatrisation of the edge (absence of post-operative biliary and blood collections; After the pilot study we operated with this technique on another 5 patients (overall period June 2005 - February 2007; M=10, F=1; age-range 37-75 years). Pre-operative work-up, both laboratory and radiological, was the usual for liver neoplasms, while peri- and post-operative consisted of blood count, laboratory and coagulative tests in the first, third

6 and seventh post-operative days, and after one and three months; liver ultrasonography and echo- colour Doppler in the first and seventh days and after one and three months; tumour markers after one month; out-patient checks after 15 days and one and three months; radiology checks (CT and/or MR with contrast medium) after three months. A total of 8 patients were affected by liver metastases from colorectal cancer; 2 patients had suspected tumour whose definitive histopathology indicated carcinoma in one case and chronic cholecystitis in the other; 1 patient was affected by a suspected intra-hepatic cholangiocarcinoma that at the definitive histological examination turned out to be post-infarction necrosis. In the group of patients with metastatic disease of the liver, 2 were affected by a single lesion, 4 by two and 2 by three. 3 left lobectomies, one left , 3 right , one right lateral sectorectomy, 4 wedge resections and 2 resections of the gall bladder bed were carried out. In 3 patients, in association with the resection, monopolar RF ablation with one metastasis was carried out; in another 3 patients, one intestinal ileo-colic anastomosis, one total with splenectomy, one a closure of were respectively carried out. Vascular control of the inflow vessels was carried out in all of the formal resections those of a patient undergoing left lobectomy and a patient undergoing a right lateral sectorectomy. The hepatic veins were divided by an EndoGIA laparoscopic stapler. The Pringle manoeuvre was never carried out. The parenchymal transection was executed with a common scalpel along the necrotic plane obtained by means of the two parallel applications of the probe. In close proximity to the hilus elements, the vena cava or hepatic veins, the transection was effected using kelly-clasia. The liver edge was never treated with argon or substances facilitating haemostasis. TABLE Pz Pre-op N° Surgical procedure Vascular Post-op Complication Trtasfusion diagnosis lesions Control diagnosis 1 meta 1 Left hepatectomy Portal and meta no 0 sovrahepatic vein 2 meta 3 Left lobectomy Portal meta Collection with 0 wedge 7° spontaneous RF 8° resolution 3 Gallbladder resections of the gall bladder no cholecystitis no 1 U carcinoma bed haematoma of the abdominal wall 4 Cholangio- Left lobectomy no post- 0 carcinoma infarction necrosis 5 meta 2 Left lobectomy Portal meta no 0 RF 8° Ileo-colic anostomosis 6 meta 3 Wedge resection no meta no 0 total colectomy, with ileo- anastomosis 7 meta 1 Right Hepatectomy Portal meta no 0 closure of ileostomy and terminal 8 meta 2 Resection of VI + VII seg. no meta no 0 RF 4° 9 meta 2 Right Hepatectomy Portal meta Collection with 0 percutaneous drainage 11 Gallbladder resections of the gall bladder no carcinoma no 0 carcinoma bed

7 Results

Neither gaseous embolisms nor thromboses of the hepatic veins were found. The use of our apparatus did not bring about repercussions on the cardiac-respiratory functions. Coagulation time for each application of the comb, excluding vascular control, was about 3 minutes for the first and about 1 minute for the parallel one; about 1 minute for the first and 45 seconds for the second wherever closure of the relative portal and arterial branch was carried out. Each application of the probe determined a necrotic “slice” of about 3.5 cm length, about 1-1.2 cm width, and depth equal to that of the insertion of the electrode needles. Transaminases, to be correlated to the parenchymal necrosis, were normalized on average in the seventh day, analogically to that verified with ablation through monopolar RFA of the neoplastic nodules; D-dimers were normalized on average within one month. Blood losses during the transectional phase were between 30 and 50 cc. Biliary fistula or abscesses were not found. The average postoperative stay in hospital was 9.8 days (range 8-18 days). One patient died through acute myocardial infarction during the immediate postoperative period; despite full-dose heparin treatment, there was no bleeding of the liver edge. Only one patient, affected by platelet deficiency, was transfused with 1 unit of red blood cells for acute anaemia caused by haematoma of the abdominal wall probably originating from the positioning of the draining tube. In two patients there was serum collection with spontaneous resolution in one case and percutaneous drainage in the other. One patient, who underwent right hepatectomy and closure of the ileostomy, manifested a prolonged post-operative dynamic ileus with spontaneous resolution and discharge on the 18th day. Average follow-up in the case of neoplastic patients was 9.3 months (range 1-21 months). No recurrence has been found on the liver edge during CT checks; one local recurrence, however, was found in a metastasis treated with monopolar RFA in a patient who underwent a contemporaneous left lobectomy and intestinal recanalization.

Discussion

Bleeding, together with hepatic impairment and biliary fistula, are the principal problems in resectional liver surgery. Intra-operative blood losses are correlated with a higher morbidity and reduced long-term survival due to negative effects on the immunity function (2). The numerous means for haemostasis available can be divided into those which are useful during the transectional phase (harmonic scalpel, ultrasonic dissector, tissuelink floating ball, ligasure vessel sealing system, water-jet dissector, humid bipolar cautery, clips, laparoscopic stapler) (6-16) and those to use in the haemostasis of the liver edge (argon beam, fibrin glue, floseal, tachosil). The scenario is very varied and the choice generally depends on the individual preferences of the surgeon; often, more than one instrument is used during the same operation. One can mention, for example, the use of CUSA and humid bipolar cautery (13), of the ultrasonic dissector and ligasure (14) and even two surgeons operating contemporaneously, one using the ultrasonic dissector and the other the other tissue-link.(15). Nevertheless, resection by means of traditional kelly-clasia is still appropriate. Lesurtel, working with the idea that one ideal instrument should allow a liver resection with minimum blood loss without the need for”inflow occlusion” (8), carried out a study on four groups of 25 non-cirrhotic and non-colestatic patients. The patients were randomized into “clamp crushing technique” with Pringle manoeuvre as against CUSA, hydro jet, or tissue link without Pringle manoeuvre, primary end-points being blood loss and liver damage. The Author concluded that liver resection through kelly-clasia was associated with a reduced execution time, less blood loss and reduced need for transfusions compared with the other three groups. Aldrighetti studied the feasibility and efficacy of resection through the combined use of the ultrasonic dissector and the Harmonic Scalpel in 100 patients compared with 100 patients operated with “clamp-crushing” (16). The use of the ultrasonic dissector and the Harmonic Scalpel facilitated

8 execution of liver resections with reduced blood loss and fewer complications, however at a cost of a longer time during the transectional phase. Habib was the first to introduce the use of monopolar radiofrequency in liver resection (17). The radiofrequency energy is applied through a single monopolar electrode at about 2 cm from the edge of the nodule. The repeated application of the electrode realized a peri-tumoral necrotic zone such as to allow the transection (at about 1 cm from the nodule) by means of a normal scalpel, leaving intact a quantity of coagulated parenchyma of another 1 cm thickness. Wedge and segmental resections realized through this innovative technique on 15 patients were carried out without stitches, clips or glue and were correlated with minimal blood loss (30 + 10 ml). This technique was later applied to larger resections (18). In a recent study (24), out of 156 consecutive patients who underwent “RF assisted liver resection” and who went from simple “wedges” to right hepatectomies, there was a modification of the technique with the introduction of the electrode at 1 cm from the tumour edge. Blood losses were 139 + 222 ml (average 50 ml; range 10 – 1100 ml) with larger losses in the larger hepatectomies and need for transfusions in 9 patients (5%). There were also 17 collections and 4 biliary leakages, of which 2 correlated to the liver edge. The Authors stress the fact that RF energy cannot be applied close to the hilus structures or the hepatic vein and that the technique itself, due to the multiple applications of the electrode, require an excessive execution time. With a view to reducing coagulation times, a bipolar multi-electrode device (Habib 4x) has been developed. This device was used in 33 cases, of which 14 underwent right hepatectomy, and permitted, after ligation of the right branch of the hepatic vein, faster coagulation of the parenchyma and the right hepatic vein (facilitated by parenchymal compression) (25). Zacharoulis (26) reports that the method is feasible, safe and able to significantly simplify haemostasis and transection. Caution is expressed regarding the application of the probe close to the hilus structures and the hepatic vein. Gananadha and Morris (27) realized a prototype probe with 11 in-line electrodes connected to a RITA 1500 generator (RITA Medical Systems, Mountain view, CA, USA) with a view to realizing a plane of coagulation in animal modal liver parenchyma. This device works in bipolar mode and the current passes between electrodes of opposing polarity. The method is named ILRFA (in-line radiofrequency ablation). The Authors compared resection with use of the ultrasonic dissector or kelly-clasia with or without preliminary coagulation. They later refined, and experimentally tested on sheep liver, a probe with six variable-depth electrode needles on a support (28), and finally effected application in a clinical setting on eight patients suffering from primitive and secondary liver neoplasms (29). Segmentectomies, bisegmentectomies and one right hepatectomy were carried out. Half of each resection was effected through use of the ultrasonic dissector after ILRFA and half with only the ultrasonic dissector. The interventions were carried out without reducing the CVP; in one patient, it was necessary to carry out the Pringle manoeuvre during the phase in which the ultrasonic dissector alone was used. ILRFA was associated with less blood loss, statistically significant. Another method of coagulation through in-line electrodes was reported by Lupo (30). The Radionics cluster consisting of 3 cooled-tip needles was modified so as to align the needles themselves. Two clusters with 6 aligned needles, fixed by means of an ad hoc device make up a probe to coagulate the section plane. 24 patients underwent resection through this technique; the control group was made up of 26 patients who received resection through “clamp-crushing” and bipolar coagulation; neither hilus clamping nor the Pringle manoeuvre were used. In the RFA – LR group, less blood loss was found in 8 out of 24 patients transfused as against 13 out of 26 in the “clamp-crushing” group (a statistically insignificant difference). No complications were found in the “clamp-crushing” group while, in the RFA-LR group, 6 patients developed abscesses, 3 biliary fistulas and 1 biliary stenosis. According to the authors, these complications were due to the necrotic tissue remaining that can constitute pabulum for bacterial growth and the development of an abscess. Late detachment of necrotic tissue can cause biliary leakage and the formation of fistulas.

9 The Surtron SB apparatus consists of a generator and a fixed six-needle in-line probe working in incremental bipolar mode. The parenchymal coagulation was well tolerated without the appearance of adverse reactions or the onset of complications. Each application determines a “slice” of necrosis of 3.5 cm length, about 1.2 cm width with full depth, analogically to what was experienced on the animal model (22,23). Necrosis obtained through the double line technique is realized in a short time, is efficacious and is of a sufficient depth to allow easy transection. On the other hand, the use of electrodes and generators dedicated to the ablation of neoplastic nodules involves volumes and not “slices” of necrosis and consequently produces excessive necrosis of healthy tissue with the complications shown (24, 30). The amount of necrotic tissue remaining in place, where it does not generate complications, constitutes in itself an advantage as it prevents neoplastic recurrence on the liver edge itself. None of our patients showed recurrence there. Contrariwise to the preceding authors who use currently-available generators for the ablation of neoplastic nodules, our generator is absolutely original and specifically designed for the purpose. It is able to automatically set the power to be delivered and, also automatically, to switch out each electrode in turn upon coagulation. The six-needle probe (comb) is easy to handle as also the protective device. In any case, we consider that it is fundamental that the preliminary acquisition of technical details and execution from the first operations be done in the presence of surgeons who have already used the device. The execution of wedge resections is facilitated as well as the exeresis of esophytic nodules. This can be advantageous in the context of hepatocarcinoma on cirrhosis with a view to saving residual parenchyma. In the case of segmentary or major resections, the coagulation is carried out on the anatomic plane after careful echographic evaluation that allows localization of the glissonian pedicles, the hepatic veins and their relationship to the tumoral nodule. The comb can be inserted in both vertical and antero-posterior modes. We maintain that it is dangerous to use the comb close to the liver hilus and that the coagulation of hepatic veins is imprudent. The technique is directed essentially at parenchymal coagulation even if we have carried out a left lobectomy and a right lateral sectorectomy without preparation and section of the respective peduncles. Blood losses noted were minimal and no patient was transfused, including the 4 who underwent major resections. Just 1 patient, deficient in platelets, received one unit of red blood cells for anemization caused by haematoma of the abdominal wall probably originating from the positioning of the draining tube. The absence of blood loss in the patient who received a full dose of heparin for acute myocardial infarction is tangible proof of the efficacy of the haemostasis of the liver edge.

Conclusions

Parenchymal coagulation realized through the SURTRON SB is safe and efficacious and allows liver resection with negligible blood loss. The double line of application of the multi-electrode probe gives easier transection by common scalpel. The use of the apparatus and probe turned out to be relatively simple and manageable, even though we consider a brief learning period to be necessary. With a view to evaluating the efficacy and eventual complications, there is a need for further acquisition of clinical experience, including its application in cirrhotic . Comparative testing can clarify the true benefit with respect to the other resection methods. Following appropriate experimentation we envisage its laparoscopic application, use in the resections of other solid organs and in hepatic traumas. Wider case series and longer follow-ups are necessary in order to demonstrate whether the quantity of necrotic tissue on the liver edge is able to avoid neoplastic recurrence in that location.

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