M. Pandolfi

Theoretical Analysis and Experimental Evaluation of Laser-Induced Interstitial Thermotherapy in Ex Vivo Porcine Pancreas

Laser-induced interstitial thermotherapy (LITT) has been recently applied to pancreas in animal models for ablation purpose. Assessment of thermal effects due to the laser-pancreatic tissue interaction is a critical factor in validating the procedure feasibility and safety. A mathematical model based on bioheat equation and its experimental assessment was developed. The LITT procedure was performed on 40 ex vivo porcine pancreases, with an Nd:YAG (1064 nm) energy of 1000 J and power from 1.5 up to 10 W conveyed by a quartz optical fiber with 300 μm diameter. Six fiber Bragg grating sensors have been utilized to measure temperature distribution as a function of time at fixed distances from the applicator tip within pancreas undergoing LITT. Simulations and experiments show temperature variations ΔT steeply decreasing with distance from the applicator at higher power values: at 6 W, ΔT >; 40°C at 5 mm and ΔT ≅ 5°C at 10 mm. ΔT nonlinearly increases with power close to the applicator. Ablated and coagulated tissue volumes have also been measured and experimental results agree with theoretical ones. Despite the absence of data in the current literature on pancreas optical parameters, the model allowed a quite good prediction of thermal effects. The prediction of LITT effects on pancreas is necessary to assess laser dosimetry.

Theoretical assessment of principal factors influencing laser interstitial thermotherapy outcomes on pancreas

The influence of some therapy-relevant parameters on Laser Induced Interstitial Thermotherapy (LITT) outcomes on pancreas is assessed. The aim is to execute a sensitivity analysis for an optimal treatment strategy on in vivo pancreas. A numerical model based on Bioheat Equation has been implemented to assess the influence of laser settings (power P and energy E), applicator radius (rf) and optical properties (effective attenuation coefficient, μeff) on temperature (T) distribution. Effects on pancreas undergoing LITT have been evaluated with a twofold approach: 1) T rise and maximum T (Tmax) in tissue; 2) injured volumes (vaporized and coagulated ones). We consider parameters range in typical LITT values (P from 1.5 W to 6 W, E from 500 J to 1500 J, rf from 150 μm to 600 μm) and optical values reported in literature. Our analysis shows that, among others, P and μeff are the principal influencing factors of thermal effects on pancreas undergoing LITT: P should be carefully chosen by operator to obtain the desired injured volumes, while the accurate measurement of tissue optical properties is crucial to carry out a safe and controlled thermal therapy on pancreas.

Superior mesenteric artery syndrome diagnosed with linear endoscopic ultrasound

teric artery (SMA) syndrome, which were diagnosed with the aid of linear endoscopic ultrasound (EUS). A 20-year-old man (case 1) presented with a 3-month history of right upper quadrant pain, postprandial vomiting, and weight loss of 4 kg. Laboratory tests revealed a serum alkaline phosphatase (ALP) level of 127 U/L (normal range 34– 104 IU/L) and an amylase level of 62 U/L (normal range 0–54 U/L). A 25-year-oldwoman (case 2) with a body mass index (BMI) of 17.8 kg/m2 presented 1 month after undergoing laparoscopic cholecystectomy. She had a 12-month history of epigastric and right upper quadrant pain, with daily postprandial projectile vomiting since the past 2 months. She had lost 50 kg in weight in 1 year. On physical examination she had an asthenic habitus and bowel sounds were present in the upper abdomen. Laboratory tests revealed hemoglobin 11.8 g/dL, mean cell hemoglobin (MCH) 26.7 pg, γ-glutamyl transferase (GGT) 56 U/L (normal range 5–55 U/L), aspartate aminotransferase 64 U/L (normal range 10–31 U/L), and alanine aminotransferase 85 U/L (normal range 10–31 U/L). On the basis of the clinical and laboratory findings we carried out further investigations including linear EUS (Pentax EG3830UT; Pentax Europe GmbH, Hamburg, Germany) and secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP; Siemens Magnetom Avanto 1.5 T; Secrelux Sanochemia, Neuss, Germany). The EUS examination did not show any major signs of chronic pancreatitis, biliary sludge, or stones in the common bile duct in both cases. However, the SMAwas seen to be running almost parallel to the abdominal aorta, with an angle between the two vessels of 8° in the patient in case 1 and 10° in the patient in case 2 (● Fig. 1). On S-MRCP, in both patients, progressive dilation of the proximal duodenum was seen with a sudden interruption (● Fig. 2), and, in the sagittal plane, the angle between the abdominal aorta and the SMAwas reduced (● Fig. 3). The patient in case 1 became asymptomatic after gaining weight, without any treatment. The patient in case 2 underwent partial gastrectomy, with Roux-enY gastrojejunostomy and Roux-en-Y duodenojejunostomy. SMA syndrome is typically caused by a decrease in the angle between the SMA and the abdominal aorta to 6–25° [1]; often this is because of loss of the mesenteric fat pad [2]. To our knowledge, the role of EUS in the diagnosis of SMA syndrome as reported in literature has been limited to the use of a radial miniprobe and in the pediatric population [3]. No posture-dependent differences have been reported in the values of the angles seen on EUS with the patient in lateral decubitus and supine positions [4]. Therefore, although neither EUS nor S-MRCP are included in classic diagnostic algorithms [5] they can be useful tools in young patients with symptoms of high intestinal obstruction accompanied by rapid weight loss.

Temporary FC-SEMS for type II ERCP-related perforations: a case series from two referral centers and review of the literature*

Abstract Background and aim: Some case reports have shown that fully covered self-expandable metal stents (FC-SEMS) are effective in cases of Stapfer Type II perforation as rescue treatment. The aim of the study was to assess the efficacy and safety of temporary placement of FC-SEMS as primary treatment for Type II perforations and review the literature regarding the use of FC-SEMS in this setting. Patients and method: Retrospective analysis of consecutive patients with Type II perforation treated with immediate placement of FC-SEMS. Primary outcomes were need for surgery and mortality rate. Secondary outcomes were complications, technical and clinical success, time to post-operative feeding, length of the hospitalization and time to stent removal. Results: Overall, 18 consecutive patients were enrolled (median age 71.5). All patients were treated with FC-SEMS (6–10u2009mm, 4–8u2009cm long). In all patients, there were no need for surgery, and no patient died. Technical and clinical success were achieved both in 100% of cases. The median time to stent removal was 43 (2–105) days. The median hospital stay was of 10 (4–21) days. Median time to post-operative feeding was 4 days (2–15). Conclusion: FC-SEMS placement could be a safe and effective treatment in Type II perforations and represent a valuable development and innovation of conservative treatment.

Colo-rectal endoscopic full-thickness resection (EFTR) with the over-the-scope device (FTRD®): A multicenter Italian experience

BACKGROUND AND AIMnEndoscopic full-thickness resection(EFTR) with FTRD® in colo-rectum may be useful for several indications.The aim was to assess its efficacy and safety.nnnMATERIAL AND METHODSnIn this retrospective multicenter study 114 patients were screened; 110 (61M/49F, mean age 68u202f±u202f11u202fyears, range 20-90) underwent EFTR using FTRD®. Indications were:residual/recurrent adenoma (39), incomplete resection at histology (R1 resection) (26), non-lifting lesion (12), adenoma involving the appendix (2) or diverticulum (2), subepithelial lesions(10), suspected T1 carcinoma (16), diagnostic resection (3). Technical success (TS: lesion reached and resected), R0 resection (negative lateral and deep margins),EFTR rate(all layers documented in the specimen) and safety have been evaluated.nnnRESULTSnTS was achieved in 94.4% of cases. EFTR was achieved in 91% with lateral and deep R0 resection in 90% and 92%. Mean size of specimens was 20u202fmm (range 6-42). In residual/recurrent adenomas, final analysis revealed: low-risk T1 (11), adenoma with low-grade dysplasia (LGD) (24) and high-grade dysplasia (HGD) (3), scar tissue (1). Histology reports of R1 resections were: adenoma with LGD (6), with HGD (1), low-risk (6) and high-risk (1) T1, scar tissue (12). Non-lifting lesions were diagnosed as: adenoma with HGD (3), low-risk (7) and high risk (2) T1. Adverse clinical events occurred in 12 patients (11%),while adverse technical events in11%. Three-months follow-up was available in 100 cases and residual disease was evident in only seven patients.nnnCONCLUSIONSnEFTR using FTRD® seems to be a feasible, effective and safe technique for treating selected colo-rectal lesions. Comparative prospective studies are needed to confirm these promising results.

P.03.9 FEASIBILITY OF EUS-GUIDE ND: YAG LASER ABLATION OF THE HEPATOCELLULAR CARCINOMA

Background and aim: We previously described a case of EUS-guided Nd:YAG (neodymium:yttrium-aluminium-garnet) LA of a HCC lesion located into the caudate lobe, not suitable for percutaneous approach. Aim is to confirm the feasibility of EUS-guided Nd:YAG LA of HCC in unsafe conditions for the percutaneous approach. Material and methods: Treatment was performed in 2 patients with multifocal HCC unsuitable for surgical resection or liver transplant. First one was affected by criptogenetic liver cirrhosis Child-Pugh A6 and lesion was site in the caudate lobe with huge ombelical vein and portal hypertension. The location of the lesion and the difficult ultrasonography visualization precluded percutaneous treatment. Second patient was affected by HCV and HIV cirrhosis Child-Pugh B9 with ascites and portal hypertension. Both patients underwent previous failed transarterial embolization (TACE) and RFA of lesions located into segment 1 and 3 respectively. Trans-gastric EUS-puncture was performed using a 22-gauge needle following the application of Doppler. A Nd:YAG laser with a wavelength of 1.064 nm was used. As previously described the treatment was planned taking into account the baseline volume of the lesions at EUS and the volume of necrosis that could be achieved in relation to the energy delivered. Results: Lesions were easier targeting through the lesser gastric curve. Application of Nd:YAG LA did not have any negative effect on the quality of the EUS images during the treatment and the whole treated area was occupied by an irregular and poorly defined echogenic zone at the end. The patients didn’t report any pain or abdominal discomfort after treatment and were discharged on the third postoperative day without complications. CT performed 24 hours after procedure showed the whole treated area replaced by an homogeneous, hypoattenuating, nonenhancing area. At 2 months follow-up clinical examination and blood analysis tests were normal. CT-scan showed uniform hypoattenuation without enhancement in the ablated zone and confirm the success to ablate the entire lesion. Conclusions: EUS-guided Nd:YAG LA of a HCC is feasible and safe in lesions in which the percutaneous approach is unsure. This promising results need to be confirmed in additional patients with lesions difficult to reach by conventional ablative methods or in patients whit compromised clinical conditions.