The challenge of extraabdominal desmoid tumour management in patients with Gardner's syndrome: radiofrequency ablation, a promising option.

Desmoid tumours are benign, myofibroblastic stromal neoplasms common in Gardner's syndrome, which is a subtype of familial adenomatous polyposis characterized by colonic polyps, osteomas, thyroid cancer, epidermoid cysts, fibromas and sebaceous cysts. The primary treatment is surgery, followed by adjuvant radiotherapy, but the local recurrence rate is high, and wide resection can result in debilitating loss of function. We report the case of a 39-year-old man with Gardner's syndrome who had already undergone a total prophylactic colectomy. He developed desmoid tumours localized in the mesenteric root, abdominal wall and dorsal region, which were treated from 2003 through 2013 with several surgical procedures and percutaneous radiofrequency ablation. In 2008 and 2013, RFA was applied under ultrasonographic guidance to two desmoid tumours localized in the dorsal thoracic wall. The outcomes were low-grade pain and one case of superficial skin necrosis, but so far there has been no recurrence of desmoid tumours in these locations. Surgical resection remains the first-line therapy for patients with desmoid tumours, but wide resection may lead to a poor quality of life. Radiofrequency ablation is less invasive and expensive and is a possible therapeutic option for desmoid tumours in patients with Gardner's syndrome.

Two-stage hepatectomy after autologous CD133+ stem cells administration: a case report.

Liver resection is the mainstay of treatment for patients with primary and metastatic liver tumors. However, a large majority of patients present for initial medical evaluation with primary and metastatic liver tumors when their cancer is unresectable. Several trials have been undertaken to identify alternative treatments and complementary therapies. In the near future, the field of liver surgery will aim to increase the number of patients that can benefit from resection, since radical removal of the tumor currently provides the sole chance of cure. This paper reports the case of a patient with an advanced colonic cancer in the era of stem cell therapy. In 2011, a 57 years old white Caucasian man with a previous history of non-Hodgkin lymphoma (NHL) was diagnosed with colon cancer and bilobar liver metastases. Following neoadjuvant therapy, the patient was enrolled in a protocol of stem cell administration for liver regeneration. Surgery was initially performed on the primary cancer and left liver lobe. An extended right lobectomy to S1 was then performed after a portal vein embolization (PVE) and stem cell stimulation of the remaining liver. The postoperative course was uneventful and the patient was free of disease after 12 months. Extreme liver resection can provide a safer option and a chance of cure to otherwise unresectable patients when liver regeneration is boosted by PVE and stem cell administration.

Combined use of intraoperative ultrasound and indocyanine green fluorescence imaging to detect liver metastases from colorectal cancer.

OBJECTIVES: Surgical excision is the standard strategy for managing liver metastases from colorectal carcinoma. The achievement of negative (R0) margins is a major determinant of disease-free survival in these patients. Current imaging techniques are of limited value in achieving this goal. A new approach to the intraoperative detection of colorectal liver metastatic tissue based on the emission of indocyanine green (ICG) fluorescence was evaluated. METHODS: A total of 25 consecutive patients with liver metastases from primary colorectal cancers who were eligible for liver resection received a bolus of ICG (0.5 mg/kg body weight) 24 h before surgery. During surgery, ICG fluorescence, which accumulates around lesions as a result of defective biliary clearance, was detected with a near-infrared camera system, the Photodynamic Eye (PDE). Numbers of lesions detected by, respectively, PDE + ICG, intraoperative ultrasound (IOUS) and preoperative computed tomography (CT) were recorded. RESULTS: The near-infrared camera plus ICG revealed a total of 77 metastatic liver nodules. Preoperative CT demonstrated 45 (58.4%) and IOUS showed 55 (71.4%). Preoperative CT and IOUS alone were inferior to the combined use of PDE + ICG and IOUS in the detection of lesions of ≤ 3 mm in size. CONCLUSIONS: This experience suggests that PDE + ICG, combined with IOUS, may represent a safe and effective tool for ensuring the complete surgical eradication of liver metastases from colorectal cancer.

Repeated radiofrequency ablation for management of patients with cirrhosis with small hepatocellular carcinomas: a long-term cohort study.

UNLABELLED: In most patients with cirrhosis, successful percutaneous ablation or surgical resection of hepatocellular carcinoma (HCC) is followed by recurrence. Radiofrequency ablation (RFA) has proven effective for treating HCC nodules, but its repeatability in managing recurrences and the impact of this approach on survival has not been evaluated. To this end, we retrospectively analyzed a prospective series of 706 patients with cirrhosis (Child-Pugh class ≤ B7) who underwent RFA for 859 HCC ≤ 35 mm in diameter (1-2 per patient). The results of RFA were classified as complete responses (CRs) or treatment failures. CRs were obtained in 849 nodules (98.8%) and 696 patients (98.5%). During follow-up (median, 29 months), 465 (66.8%) of the 696 patients with CRs experienced a first recurrence at an incidence rate of 41 per 100 person-years (local recurrence 6.2; nonlocal 35). Cumulative incidences of first recurrence at 3 and 5 years were 70.8% and 81.7%, respectively. RFA was repeated in 323 (69.4%) of the 465 patients with first recurrence, restoring disease-free status in 318 (98.4%) cases. Subsequently, RFA was repeated in 147 (65.9%) of the 223 patients who developed a second recurrence after CR of the first, restoring disease-free status in 145 (98.6%) cases. Overall, there were 877 episodes of recurrence (1-8 per patient); 577 (65.8%) of these underwent RFA that achieved CRs in 557 (96.5%) cases. No procedure-related deaths occurred in 1,921 RFA sessions. Estimated 3- and 5-year overall and disease-free (after repeated RFAs) survival rates were 67.0% and 40.1% and 68.0 and 38.0%, respectively. CONCLUSION: RFA is safe and effective for managing HCC in patients with cirrhosis, and its high repeatability makes it particularly valuable for controlling intrahepatic recurrences.

Effects of preoperative oral carbohydrate supplementation on postoperative metabolic stress response of patients undergoing elective abdominal surgery.

BACKGROUND: The goal of the present study was to evaluate the effects of preoperative oral carbohydrate supplementation (OCH) on the postoperative metabolic stress response of patients undergoing elective abdominal surgery. METHODS: The study was designed as a controlled, prospective, cohort study including 38 patients treated with OCH (800 mL the day before surgery and 400 mL within 3 h before the induction of anesthesia) and 38 controls matched for surgical procedure. Fasting glucose, insulin, insulin resistance (HOMA-IR index), cortisol, and interleukin 6 (IL-6) were assessed before and after surgery (postoperative day (POD) 1, 2, and 3). RESULTS: The administration of OCH resulted in lower fasting glucose, HOMA-IR index, cortisol, and IL-6 on both POD 1 and POD 2. At multivariable regression analyses, the reduction of these parameters was independent of sex, age, body mass index, and major abdominal surgery. Particularly, models including OCH treatment explained 70, 63, and 66 % of the variance of the increase in IL-6 levels at POD 1, POD 2, and POD 3, respectively. The effect of OCH on changes in glucose, insulin resistance, and cortisol on POD 1 and POD 2 disappeared after the inclusion of IL-6 in the models. CONCLUSIONS: Treatment with OCH was associated with attenuation of the postoperative metabolic stress response. We hypothesize that modulation of the inflammatory response is one of the mechanisms involved.

Autologous bone marrow-derived mesenchymal stromal cells in the treatment of fistulising Crohn's disease.

OBJECTIVE: External fistulas represent a disabling manifestation of Crohn's disease with a difficult curability and a high relapse rate despite a large therapeutic armamentarium. Stem cell therapy is a novel and promising approach for treatment of chronic inflammatory conditions. We therefore investigated the feasibility, safety and efficacy of serial intrafistular injections of autologous bone marrow-derived mesenchymal stromal cells (MSCs) in the treatment of fistulising Crohn's disease. PATIENTS AND METHODS: We enrolled 12 consecutive outpatients (eight males, median age 32 years) refractory to or unsuitable for current available therapies. MSCs were isolated from bone marrow and expanded ex vivo to be used for both therapeutic and experimental purposes. Ten patients (two refused) received intrafistular MSC injections (median 4) scheduled every 4 weeks, and were monitored by surgical, MRI and endoscopic evaluation for 12 months afterwards. The feasibility of obtaining at least 50×106 MSCs from each patient, the appearance of adverse events, and the efficacy in terms of fistula healing and reduction of both Crohn's disease and perianal disease activity indexes were evaluated. In addition, the percentage of both mucosal and circulating regulatory T cells expressing FoxP3, and the ability of MSCs to influence mucosal T cell apoptosis were investigated. RESULTS: MSC expansion was successful in all cases; sustained complete closure (seven cases) or incomplete closure (three cases) of fistula tracks with a parallel reduction of Crohn's disease and perianal disease activity indexes (p < 0.01 for both), and rectal mucosal healing were induced by treatment without any adverse effects. The percentage of mucosal and circulating regulatory T cells significantly increased during the treatment and remained stable until the end of follow up (p < 0.0001 and p < 0.01, respectively). Furthermore, MSCs have been proven to affect mucosal T cell apoptotic rate. CONCLUSIONS: Locally injected MSCs represent a feasible, safe and beneficial therapy in refractory fistulising Crohn's disease.

Diversity and ethics in trauma and acute care surgery teams: results from an international survey.

BACKGROUND: Investigating the context of trauma and acute care surgery, the article aims at understanding the factors that can enhance some ethical aspects, namely the importance of patient consent, the perceptiveness of the ethical role of the trauma leader, and the perceived importance of ethics as an educational subject. METHODS: The article employs an international questionnaire promoted by the World Society of Emergency Surgery. RESULTS: Through the analysis of 402 fully filled questionnaires by surgeons from 72 different countries, the three main ethical topics are investigated through the lens of gender, membership of an academic or non-academic institution, an official trauma team, and a diverse group. In general terms, results highlight greater attention paid by surgeons belonging to academic institutions, official trauma teams, and diverse groups. CONCLUSIONS: Our results underline that some organizational factors (e.g., the fact that the team belongs to a university context or is more diverse) might lead to the development of a higher sensibility on ethical matters. Embracing cultural diversity forces trauma teams to deal with different mindsets. Organizations should, therefore, consider those elements in defining their organizational procedures. LEVEL OF EVIDENCE: Trauma and acute care teams work under tremendous pressure and complex circumstances, with their members needing to make ethical decisions quickly. The international survey allowed to shed light on how team assembly decisions might represent an opportunity to coordinate team member actions and increase performance.

A metachronous splenic metastases from esophageal cancer: a case report.

The spleen is an infrequent site for metastatic lesions, and solitary splenic metastases from squamous cell carcinoma of the esophagus are very rare: only 4 cases have been reported thus far. These lesions are whitish nodules that are macroscopically and radiologically similar to primary splenic lymphomas. We report a case of metachronous splenic metastases from esophageal cancer and multiple splenic abscesses, which developed nine months after apparently curative esophagectomy without adjuvant chemotherapy. The patient underwent splenectomy dissection followed by adjuvant chemotherapy, but liver and skin metastases developed, and the patient died 9 months later.

Nutritional parameters associated with prolonged hospital stay among ambulatory adult patients.

BACKGROUND: Comprehensive evaluations of the nutritional parameters associated with length of hospital stay are lacking. We investigated the association between malnutrition and length of hospital stay in a cohort of ambulatory adult patients. METHODS: From September 2006 to June 2009, we systematically evaluated 1274 ambulatory adult patients admitted to hospital for medical or surgical treatment. We evaluated the associations between malnutrition and prolonged hospital stay (> 17 days [> 75th percentile of distribution]) using multivariable log-linear models adjusted for several potential nutritional and clinical confounders recorded at admission and collected during and at the end of the hospital stay. RESULTS: Nutritional factors associated with a prolonged hospital stay were a Nutritional Risk Index score of less than 97.5 (relative risk [RR] 1.64, 95% confidence interval [CI] 1.31-2.06) and an in-hospital weight loss of 5% or greater (RR 1.60, 95% CI 1.30-1.97). Sensitivity analysis of data for patients discharged alive and who had a length of stay of at least three days (n = 1073) produced similar findings (adjusted RR 1.51, 95% CI 1.20-1.89, for Nutritional Risk Index score < 97.5). A significant association was also found with in-hospital starvation of three or more days (RR 1.14, 95% CI 1.01-1.28). INTERPRETATION: Nutritional risk at admission was strongly associated with a prolonged hospital stay among ambulatory adult patients. Another factor associated with length of stay was worsening nutritional status during the hospital stay, whose cause-effect relationship with length of stay should be clarified in intervention trials. Clinicians need to be aware of the impact of malnutrition and of the potential role of worsening nutritional status in prolonging hospital stay.

Management of the axilla in patients with breast cancer and positive sentinel lymph node biopsy: An evidence-based update in a European breast center.

The surgical approach to the axilla in breast cancer has been a controversial issue for more than three decades. Data from recently published trials have provided practice-changing recommendations in this scenario. However, further controversies have been triggered in the surgical community, resulting in heterogeneous diffusion of these recommendations. The development of clinical guidelines for the management of the axilla in patients with breast cancer is a work in progress. A multidisciplinary team discussion was held at the research hospital Policlinico San Matteo from the Università degli Studi di Pavia with the aim to update recommendations for the management of the axilla in patients with breast cancer. An evidence-based approach is presented. Our multidisciplinary panel determined that axillary dissection after a positive sentinel lymph node biopsy may be avoided in cN0 patients with micro/macrometastasis to ≤2 sentinel nodes, with age ≥40y, lesions ≤3 cm, who have not received neoadjuvant chemotherapy and have planned breast conservation (BCS) with whole breast radiotherapy (WBRT). Cases with gross (>2 mm) ECE in SLNs are evaluated on individual basis for completion ALND, axillary radiotherapy or omission of both. Patients fulfilling the criteria listed above who undergo mastectomy, may also avoid axillary dissection after multidisciplinary discussion of individual cases for consideration of axillary irradiation. Women 70 years or older with hormone receptors positive invasive lesions ≤3 cm, clinically negative nodes, and serious or multiple comorbidities who undergo BCS with WBRT, may forgo axillary staging/surgery (if mastectomy or larger tumor, comorbidities and life expectancy are taken into account).

Orthopedic injuries in patients with multiple injuries: Results of the 11th trauma update international consensus conference Milan, December 11, 2017.

BACKGROUND: In blunt trauma, orthopedic injuries are often associated with cerebral and torso injuries. The optimal timing for definitive care is a concern. The aim of the study was to develop evidence-based guidelines for damage-control orthopedic (DCO) and early total care (ETC) of pelvic and long-bone fractures, closed or open, and mangled extremities in adult trauma patients with and without associated injuries. METHODS: The literature since 2000 to 2016 was systematically screened according to Preferred Reporting Items for Systematic Reviews and meta-analyses protocol. One hundred twenty-four articles were reviewed by a panel of experts to assign grade of recommendation and level of evidence using the Grading of recommendations Assessment, Development, and Evaluation system, and an International Consensus Conference, endorsed by several scientific societies was held. RESULTS: The choice between DCO and ETC depends on the patient's physiology, as well as associated injuries. In hemodynamically unstable pelvic fracture patient, extraperitoneal pelvic packing, angioembolization, external fixation, C-clamp, and resuscitative endovascular balloon occlusion of the aorta are not mutually exclusive. Definitive reconstruction should be deferred until recovery of physiological stability. In long bone fractures, DCO is performed by external fixation, while ETC should be preferred in fully resuscitated patients because of better outcomes. In open fractures early debridement within 24 hours should be recommended and early closure of most grade I, II, IIIa performed. In mangled extremities, limb salvage should be considered for non-life-threatening injuries, mostly of upper limb. CONCLUSION: Orthopedic priorities may be: to save a life: control hemorrhage by stabilizing the pelvis and femur fractures; to save a limb: treat soft tissue and vascular injuries associated with fractures, stabilize fractures, recognize, and prevent compartmental syndrome; to save functionality: treat dislocations, articular fractures, distal fractures. While DCO is the best initial treatment to reduce surgical load, ETC should be applied in stable or stabilized patients to accelerate the recovery of normal functions. LEVEL OF EVIDENCE: Systematic review of predominantly level II studies, level II.

Unique vascular tumor primary arising in the liver and exhibiting histopathological features consistent with so-called polymorphous hemangioendothelioma.

Reported herein is an unusual vascular tumor primary arising in the liver and exhibiting unique histopathological features. A 47-year-old woman underwent left hepatectomy because of a large hepatic mass. On histology the tumor had a composite pattern, consisting of angiomatous, retiform and solid areas, formed by oval to cuboidal to spindle cells, that expressed only endothelial markers (CD31 and factor VIII-related antigen). These findings led to the diagnosis of a low-grade vascular neoplasm with morphological features consistent with so-called polymorphous hemangioendothelioma. The tumor was completely resected. At 24 month follow up the patient was alive, without evidence of disease. Polymorphous hemangioendothelioma is a rare vascular neoplasm, with borderline malignant potential, which usually occurs in lymph nodes and, rarely, at extranodal sites. Its classification as an entity has been questioned recently. The unusual morphological features of the present case, which do not fit neatly with any other recognized hemangioendothelioma subtype, indicate that the family of vascular tumors is broader than currently accepted. In addition the present case widens the spectrum of primary vascular tumors arising in the liver.

Low-grade fibromatosis-like spindle cell metaplastic carcinoma: a basal-like tumor with a favorable clinical outcome. Report of two cases.

Fibromatosis-like spindle-cell metaplastic carcinoma (FLSpCC) is an atypical variant of spindle-cell carcinoma with a particular clinical behavior characterized by frequent local recurrence, very low potential for axillary lymph node metastasis, and uncommon distant metastases. Although it presents the typical immunoprofile of basal-like carcinomas, FLSpCC is associated with a favorable clinical outcome and conservative treatment is generally indicated. Because of the lack of specific clinical and radiological characteristics, the criteria for the differential diagnosis from other benign and malignant tumors are based only on histological findings and immunostaining. We report on two FLSpCC patients treated with wide local excision and mastectomy associated with axillary lymph node dissection. Although the biological behavior of this subtype of breast cancer has not been adequately evaluated, wide local excision or mastectomy with clear resection margins but no axillary dissection appears to be an adequate treatment approach.

A novel technique for rat liver transplantation using Quick Linker system: a preliminary result.

BACKGROUND: The clinical success of liver transplantation is founded upon years of experimental research. Since Kamada and colleagues developed the "two-cuff" technique, the rat has become the best model for extensive investigations. Although the Kamada technique is technically complex and not easy to master, it is still the mainstay of orthotopic liver transplantation in rodents. We have developed a modified three-cuff version of this technique that facilitates anastomosis and markedly reduces warm ischemia time. MATERIALS AND METHODS: The new technique involves a set of five microinstruments (the Quick-Linker system) designed and manufactured by our group. It was tested in male Lewis rats (group 1, donors n = 10, recipients n = 10). The graft was explanted as usual and standard cuffs were attached to the portal vein and the supra- and infrahepatic vena cavae. Corresponding vessels in the recipient were isolated, and Quicker-Linker holding rings were attached to each. The vessels were then clamped and the native organ removed. Once the graft was positioned in the recipient's abdomen, the holding rings attached to the recipient vessels and the cuffs applied to graft vessels were automatically aligned and joined with the aid of a special alignment tool. RESULTS: Warm ischemia times were always inferior to 6 minutes. Survival at postoperative day 10 was 80%. Liver function was well preserved in all of the surviving rats. CONCLUSIONS: The Quick-Linker technique significantly shortens warm ischemia time and allows rapid anastomosis that is relatively independent of operator skill. It can be considered a reliable option for microsurgeons looking for quick results and high success rates.

Short-term cyclosporine therapy and cotransplantation of donor splenocytes: effects on graft rejection and survival rates in pigs subjected to renal transplantation.

BACKGROUND: Donor-specific allogeneic loading can prolong the survival of solid organ transplants by inducing a state known as acceptance. Several populations of cells are known to be involved in this process, but their exact roles have yet to be defined. The aim of this study was to assess the effects of portal-vein transfusion of donor-specific splenocytes (DST) after short-term cyclosporine A (CyA) therapy in pigs subjected to renal transplantation. METHODS: Four groups of unrelated swine underwent renal transplantation with removal of the native kidneys. Antirejection protocols consisted in portal-vein DST (3 x 10(8) cells/kg) (Group 2, n = 7); intravenous CyA (9 mg/kg/d) on postoperative days 1-12 (Group 3, n = 14); and DST + CyA (as described above) (Group 4, n = 13). Results (through postoperative day 90) were compared with those obtained in untreated control recipients (Group 1, n = 7). RESULTS: Compared with animals of Groups 1, 2, and 3, Group 4 recipients presented significantly longer survival (mean: 90 days, P < 0.01 in Kaplan-Meier analysis) and better renal function (P < 0.05). Graft histology revealed preserved parenchyma. CONCLUSION: The role of spleen cells in the immune response has probably been underestimated. Cotransplantation of donor splenocytes seems to induce a certain degree of acceptance toward the renal allograft. The route of administration (portal-vein infusion in this study) may be crucial for developing favorable mechanisms of recognition.

Colonoscopy is mandatory after Streptococcus bovis endocarditis: a lesson still not learned. Case report.

BACKGROUND: Even though the relationship between certain bacterial infections and neoplastic lesions of the colon is well-recognized, this knowledge has not been sufficiently translated into routine practice yet. CASE PRESENTATION: We describe the case of a 51-year-old man who was admitted to our Surgical Department due to rectal bleeding and abdominal pain. Preoperative colonoscopy, staging exams and subsequent surgery demonstrated a stenotic adenocarcinoma of the sigmoid colon, invading the left urinary tract and the homolateral bladder wall, with regional lymph nodes involvement and massive bilobar liver metastases (T4N1M1). After Hartmann's rectosigmoidectomy and despite systemic chemotherapy, a rapid progression occurred and the patient survived for only 5 months after diagnosis. Five years before detecting this advanced colonic cancer, the patient underwent aortic valve replacement due to a severe Streptococcus bovis endocarditis. Subsequent to this infection he never underwent a colonoscopy until overt intestinal symptoms appeared. CONCLUSION: As this case illustrates, in the unusual setting of a Streptococcus bovis infection, it is necessary to timely and carefully rule out occult colon cancer and other malignancies during hospitalization and, if a tumor is not found, to schedule endoscopic follow-up. Rigorous application of these recommendations in the case described would have likely led to an earlier diagnosis of cancer and maybe saved the patient's life.

Reliability and validity assessment of administrative databases in measuring the quality of rectal cancer management.

PURPOSE: Measurement and monitoring of the quality of care using a core set of quality measures are increasing in health service research. Although administrative databases include limited clinical data, they offer an attractive source for quality measurement. The purpose of this study, therefore, was to evaluate the completeness of different administrative data sources compared to a clinical survey in evaluating rectal cancer cases. METHODS: Between May 2012 and November 2014, a clinical survey was done on 498 Lombardy patients who had rectal cancer and underwent surgical resection. These collected data were compared with the information extracted from administrative sources including Hospital Discharge Dataset, drug database, daycare activity data, fee-exemption database, and regional screening program database. The agreement evaluation was performed using a set of 12 quality indicators. RESULTS: Patient complexity was a difficult indicator to measure for lack of clinical data. Preoperative staging was another suboptimal indicator due to the frequent missing administrative registration of tests performed. The agreement between the 2 data sources regarding chemoradiotherapy treatments was high. Screening detection, minimally invasive techniques, length of stay, and unpreventable readmissions were detected as reliable quality indicators. Postoperative morbidity could be a useful indicator but its agreement was lower, as expected. CONCLUSIONS: Healthcare administrative databases are large and real-time collected repositories of data useful in measuring quality in a healthcare system. Our investigation reveals that the reliability of indicators varies between them. Ideally, a combination of data from both sources could be used in order to improve usefulness of less reliable indicators.

Effect of hyperbarism on radiofrequency ablation outcome.

OBJECTIVE: Our objective was to investigate whether increases in atmospheric or local tissue pressure would affect the outcome of radiofrequency ablation procedures and the size of the created thermal lesions. MATERIALS AND METHODS: Thermal lesions were produced in specimens of explanted bovine liver inside a hyperbaric chamber at 101 (atmospheric), 141, 202, 273, and 364 kPa using radiofrequency power settings of 20, 30, 40, and 50 W. In subsequent in vivo experiments, thermal lesions were produced in the livers of anesthetized pigs with or without occlusion of the hepatic vein draining the ablation site. RESULTS: At each radiofrequency power setting, progressive increases in applied pressure were paralleled by decreases in minimum impedance and increases in maximum tissue temperatures at the electrode tip (reflecting tissue-fluid boiling points), delivery time, total energy delivered, and thermal lesion volumes. Similar increases were observed in radiofrequency ablation procedures performed in vivo under occlusion of the vein draining the ablation site. CONCLUSION: By elevating the tissue-fluid boiling point, increased pressure delays the desiccation of tissue in contact with the radiofrequency electrode tip and the related sharp increase in impedance. The result is prolonged delivery of larger amounts of radiofrequency energy and larger thermal lesions.