Ignasi Poves

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

BackgroundEfficient 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.MethodsOur 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.ResultsThe 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).ConclusionA 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.

Laparoscopic Pancreas-Sparing Subtotal Duodenectomy

CONTEXT Primary adenocarcinoma of the duodenum is a rare digestive malignancy which is commonly treated by radical surgical resection, pancreaticoduodenectomy being the technique of choice. Complete tumor resection obtaining free margins should be the standard of treatment for primary adenocarcinoma of the duodenum. Segmental duodenal resection is an appropriate operation for selected cases of primary adenocarcinoma of the duodenum of the 3rd and 4th portions of the duodenum. CASE REPORT We present the case of a 67-year-old woman suffering from an infra-ampullary large villous polypoid mass affecting the 3rd portion of the duodenum. Multiple endoscopic biopsies did not disclose any malignancy, and abdominal CT and endoscopic ultrasound found no extraduodenal involvement. A 3rd and 4th portion pancreas-sparing duodenectomy was carried out using a totally laparoscopic approach. Intra-operatory duodenoscopy was done to safeguard the papilla of Vater. Recovery was uneventful and the patient was discharged on the 7th postoperative day. The final diagnosis was primary adenocarcinoma of the duodenum (free resection margins). After forty-five months of follow-up, the patient is free of disease. CONCLUSIONS We recommend this procedure for treatment of an infra-ampullary benign and pre-malignant duodenal pathology; it can also be a treatment option and an alternative to a pancreaticoduodenectomy in very selected cases of tumors confined to the duodenum. Expertise in both pancreatic surgery and laparoscopic techniques is required.

A new single-instrument technique for parenchyma division and hemostasis in liver resection: a clinical feasibility study

The objective of this study was to evaluate the clinical feasibility of a new technique for liver resection based on a radiofrequency-assisted (485 kHz) device that has shown high performance in the animal setting in both transection speed and blood loss per transection area. Eight patients with colorectal hepatic metastasis underwent 11 partial hepatectomies using the proposed technique for both parenchyma division and hemostasis. Main outcome measures were blood loss per transection area and transection speed. No other instruments (including sutures or clips) were used in any of the cases; temporary vascular occlusion performed was not performed. No blood transfusions were required and no mortality or morbidity linked to the hepatic procedure were observed. The median blood loss per transection area and the median transection speed were .79 mL/cm² (range, .05-7.37 mL/cm²) and 1.28 cm²/min (range, .49-1.87 mL/cm²), respectively. During the follow-up period (range, 4-12 mo) no late complications were detected and postoperative patients were free from hepatic recurrence. The proposed radiofrequency-assisted device was shown to achieve parenchymal division and hemostasis simultaneously, resulting in extremely reduced blood loss.

Distant infusion of saline may enlarge coagulation volume during radiofrequency ablation of liver tissue using cool-tip electrodes without impairing predictability.

OBJECTIVE Our aim was to evaluate the capability of a Cool-tip electrode to create larger coagulation volumes combined with a low-flow (0.1 mL/min) perfusion of hypertonic saline at a distance of 2 mm (hybrid applicator) without reducing either predictability or sphericity of the coagulation zone. MATERIALS AND METHODS A total of 48 radiofrequency ablations were performed on a total of 12 adult pigs: 24 with the Cool-tip (group 1) and 24 with the hybrid applicator (group 2). Volumes and diameters were assessed both macroscopically and with imaging techniques (ultrasound and MRI). Digital reconstruction techniques were also used. Reproducibility of the coagulations was assessed by means of the coefficient of variation. RESULTS The macroscopic assessment showed a significantly larger coagulation zone in group 2 than in group 1, both with (19.40 ± 11.38 cm(3) vs 9.16 ± 5.62 cm(3); p < 0.001) and without (19.54 ± 11.39 cm(3) vs 9.21 ± 5.74 cm(3); p < 0.001) digital reconstruction. Differences were also significant in the MRI assessment. The minimum transverse diameter was also significantly (p < 0.01) larger in group 2 than group 1: 2.46 ± 0.61 versus 1.86 ± 0.55 cm for macroscopic assessment, 2.33 ± 0.96 versus 1.69 ± 0.53 cm for ultrasound, and 2.41 ± 0.58 versus 1.8 ± 0.52 cm for MRI. The coefficient of variation was similar in both groups. CONCLUSION The results suggest that low-flow perfusion of hypertonic saline at 2 mm from a Cool-tip electrode could increase coagulation zone volume without reducing predictability.

Influence of approach on outcome in radiofrequency ablation of liver tumors

In this article some recent data concerning the approach on radiofrequency ablation (RFA) of liver tumors are reviewed. Specifically, several critical statements between surgical and percutaneous approach are raised and discussed: (1) Open approach may lead to a higher complication rate; (2) Temporary occlusion of hepatic inflow during surgical approach may lead to a higher rate of ablation of the liver tumors; (3) Surgical approach may permit better targeting of the tumor to be ablated. (4) Surgical approach may discover additional liver tumors. Finally, several conclusions and recommendations are also addressed.

Reduced risk of pancreatic cancer associated with asthma and nasal allergies.

Objective Studies indicate an inverse association between ductal adenocarcinoma of the pancreas (PDAC) and nasal allergies. However, controversial findings are reported for the association with asthma. Understanding PDAC risk factors will help us to implement appropriate strategies to prevent, treat and diagnose this cancer. This study assessed and characterised the association between PDAC and asthma and corroborated existing reports regarding the association between allergies and PDAC risk. Design Information about asthma and allergies was collated from 1297 PDAC cases and 1024 controls included in the PanGenEU case–control study. Associations between PDAC and atopic diseases were studied using multilevel logistic regression analysis. Meta-analyses of association studies on these diseases and PDAC risk were performed applying random-effects model. Results Asthma was associated with lower risk of PDAC (OR 0.64, 95% CI 0.47 to 0.88), particularly long-standing asthma (>=17 years, OR 0.39, 95% CI 0.24 to 0.65). Meta-analysis of 10 case–control studies sustained our results (metaOR 0.73, 95% CI 0.59 to 0.89). Nasal allergies and related symptoms were associated with lower risk of PDAC (OR 0.66, 95% CI 0.52 to 0.83 and OR 0.59, 95% CI 0.46 to 0.77, respectively). These results were supported by a meta-analysis of nasal allergy studies (metaOR 0.6, 95% CI 0.5 to 0.72). Skin allergies were not associated with PDAC risk. Conclusions This study shows a consistent inverse association between PDAC and asthma and nasal allergies, supporting the notion that atopic diseases are associated with reduced cancer risk. These results point to the involvement of immune and/or inflammatory factors that may either foster or restrain pancreas carcinogenesis warranting further research to understand the molecular mechanisms driving this association.

Laparoscopic-adapted Blumgart pancreaticojejunostomy in laparoscopic pancreaticoduodenectomy

BackgroundLaparoscopic pancreaticoduodenectomy (LPD) is a complex procedure that is becoming increasingly popular among surgeons. Postoperative pancreatic fistula (POPF) remains the most feared specific complication in reconstruction after PD. The Blumgart anastomosis (BA) has been established as one of the safest anastomosis for pancreas remnant reconstruction, with low rates of POPF and postoperative complications. The procedure for performing this anastomosis by laparoscopic approach has not been reported to date.MethodsWe describe our technique of LPD with laparoscopic-adapted BA (LapBA) and present the results obtained. A case-matched analysis with open cases of BA is also reported.ResultsSince February 2013 to February 2016, thirteen patients were operated of LapBA. An equivalent cohort of open PD patients was obtained by matching sex, ASA, pancreas consistency and main pancreatic duct diameter. Severe complications (grades III–IV) and length of stay were significantly lesser in LapBA group. No differences in POPF, readmission, reoperation rate and mortality were detected.ConclusionsThe LapBA technique we propose can facilitate the pancreatic reconstruction after LPD. In this case-matched study, LPD shows superior results than open PD in terms of less severe postoperative complications and shorter length of stay. Randomized control trials are required to confirm these results.

Laparoscopic Distal Pancreatectomy: Feasibility Study of Radiofrequency-Assisted Transection in a Porcine Model

BACKGROUND AND AIM Despite technological improvements in pancreatic surgery, the incidence and morbidity of pancreatic leak after resection of distal pancreas are persistently high in most series. Laparoscopic distal pancreatectomy (LDP) is today the gold standard procedure for benign and certain malignant neoplasms of the pancreatic body and tail in specialized centers. This study evaluated safety and feasibility of a radiofrequency (RF)-assisted transection device in a porcine model of LDP. MATERIALS AND METHODS LDP was performed on 10 pigs (median weight, 39.6 kg) using a new device based on an internally cooled RF-assisted electrode (Coolinside(®), Apeiron Medical, Valencia, Spain). The animals were subjected to daily observation and then sacrificed and necropsied at 4 weeks postoperatively. Primary end points were the development of postoperative pancreatic fistula using the Pancreatic Anastomotic Leak Study Group definition and/or the presence of abdominal amylase-rich fluid collections or abscesses during necropsy and pathological study and/or dye extravasation from the pancreatic remnant duct. Secondary end points were intra- or postoperative complications, surgery, and transection duration. RESULTS No clinically relevant postoperative pancreatic fistulas were observed. In one case a grade A postoperative fistula was diagnosed due to amylase drain concentration of more than 6200 IU/mL on postoperative day 4. Median peritoneal liquid amylase concentration on postoperative day 4 was 2399.0 IU/L (range, 819.2-7122.0 IU/L), similar to the median plasma amylase level of 1520.8 IU/L (range, 1015.3-4056.6 IU/L). Median surgery time was 93.5 minutes (range, 46.0-140.0 minutes), and median transection time was 4.5 minutes (range, 2.0-26.0 minutes). There was one postoperative wound infection. There were no postoperative deaths or major complications. During the histopathological study, the surgical margin of the remaining pancreas showed a common pattern with a central area of necrosis surrounded by granulomatous infiltrate and fibrosis. Ductal obliteration was observed. No purulent inflammatory infiltrate or abscesses were present. CONCLUSION Experimental findings suggest that performing pancreatic transection with Coolinside in a animal model of LDP is feasible and safe.

Resultados del abordaje laparoscópico en el tratamiento de la obstrucción aguda del intestino delgado por adherencias y hernias internas

INTRODUCTION Laparotomy is the standard approach for the surgical treatment of acute small bowel obstruction (ASBO). PATIENTS AND METHODS From February 2007 to May 2012 we prospectively recorded all patients operated by laparoscopy in our hospital because of ASBO due to adhesions (27 cases) and/or internal hernia (6 cases). A preoperative abdominal CT was performed in all cases. Patients suffering from peritonitis and/or sepsis were excluded from the laparoscopic approach. It was decided to convert to laparotomy if intestinal resection was required. RESULTS The mean age of the 33 patients who underwent surgery was 61.1 ± 17.6 years. 64% had previous history of abdominal surgery. 72% of the cases were operated by surgeons highly skilled in laparoscopy. Conversion rate was 21%. Operative time and postoperative length of stay were 83 ± 44 min. and 7.8 ± 11.2 days, respectively. Operative time (72 ± 30 vs 123 ± 63 min.), tolerance to oral intake (1.8 ± 0.9 vs 5.7 ± 3.3 days) and length of postoperative stay (4.7 ± 2.5 vs 19.4 ± 21 days) were significantly lower in the laparoscopy group compared with the conversion group, although converted patients had greater clinical severity (2 bowel resections). There were two severe complications (Clavien-Dindo III and V) in the conversion group. CONCLUSIONS In selected cases of ASBO caused by adhesions and internal hernias and when performed by surgeons highly skilled in laparoscopy, a laparoscopic approach has a high probability of success (low conversion rate, short hospital length of stay and low morbidity); its use would be fully justified in these cases.

Impact of monopolar radiofrequency coagulation on intraoperative blood loss during liver resection: a prospective randomised controlled trial

Abstract Purpose: To evaluate the impact of using monopolar thermal coagulation based on radiofrequency (RF) currents on intraoperative blood loss during liver resection. Materials and methods: A prospective randomised controlled trial was planned. Patients undergoing hepatectomy were randomised into two groups. In the control group (n = 10), hemostasis was obtained with a combination of stitches, vessel-sealing bipolar RF systems, sutures or clips. In the monopolar radiofrequency coagulation (MRFC) group (n = 18), hemostasis was mainly obtained using an internally cooled monopolar RF electrode. Results: No differences in demographic or clinical characteristics were found between groups. Mean blood loss during liver resection in the control group was more than twice that of the MRFC group (556 ± 471 ml vs. 225 ± 313 ml, p = .02). The adjusted mean bleeding/transection area was also significantly higher in the control group (7.0 ± 3.3 ml/cm2 vs. 2.8 ± 4.0 ml/cm2, p = .006). No significant differences were observed in the rate of complications between the groups. Conclusions: The findings suggest that the monopolar electrocoagulation created with an internally cooled RF electrode considerably reduces intraoperative blood loss during liver resection.