MRI-guided percutaneous transhepatic cholangiodrainage: feasibility study in a porcine model.

BACKGROUND AND STUDY AIMS: MRI-guided procedures combine high-quality imaging with lack of radiation. Percutaneous transhepatic cholangiodrainage under real-time MRI guidance (MRI-PTCD) seems promising, allowing targeted puncture and avoiding multiple blind passes and use of contrast, which are associated with standard PTCD's heaviest complications. PATIENTS AND METHODS: Aim of this study was to investigate the feasibility of MRI-PTCD in three outbred piglets. Obstructive cholestasis was induced by common bile duct ligation. Two days later, MRI-PTCD was performed (open MRI, 1.0 Tesla) with prototype MRI-compatible accessories. Visualization was achieved with a balanced steady-state free precession real-time sequence (bSSFP: 0.75 frames/s, TR/TE [ms]: 7.2/3.6; flip angle: 45°; 200 × 200 matrix size; resolution: 1.3 × 1.3 mm(2), slice thickness: 7 mm). Cannulation of the bile ducts was followed by placement of Yamakawa drainages. RESULTS: Twelve punctures were performed (four per animal, 10/12 successful); in 2/10 the bile ducts could not be cannulated. Animal survival was 100% and no significant complications occurred. CONCLUSIONS: Initial data show that MRI-PTCD can be successfully performed. This may lead to establishment of a new optimized PTCD technique compared to the standard approach under fluoroscopy.

Intraoperative localization of occult colorectal tumors during laparoscopic surgery by magnetic ring markers-a pilot study.

PURPOSE: Intraoperative localization of small tumors or malignant polyps has been an important issue in laparoscopic colon surgery. We have developed a new method for preoperative endoscopic tumor marking using a ring-shaped magnetic marker. METHODS: In a pilot study, 28 patients with small colonic (n = 23) or rectal tumors (n = 5) underwent endoscopic magnetic clipping prior to laparoscopic resection. A cap carrying a high-power neodymium ring magnet was mounted on the tip of a colonoscope. Near the lesion, the ring magnet was released and clipped to the colorectal wall. Standard laparoscopic instruments were used to find the magnet intraoperatively. RESULTS: Endoscopic fixation of a ring magnet next to the tumor by clipping was technically feasible in all 28 patients. Intraoperative localization of the marked lesions was successful in 27 of 28 patients (96 %). All patients underwent magnet-guided radical laparoscopic resection of the tumor with an average proximal and distal resection margin of 101 and 63 mm, respectively. In one case, the magnet could not be found due to preoperative migration. Surgical complications related to magnetic clip application or intraoperative tumor localization were not observed. However, there was one case with an intraoperative perforation of the colon by the magnet, which was obviously caused by unchecked action with a laparoscopic instrument. CONCLUSIONS: Preoperative endoscopic labeling of colonic lesions with on-the-scope magnetic markers is simple and safe. Intraoperative tumor localization during laparoscopic colorectal surgery can be achieved reliably without additional equipment such as ultrasound or fluoroscopy.

Laparoscopic radiofrequency ablation of liver tumors: comparison of MR guidance versus conventional laparoscopic ultrasound for needle positioning in a phantom model.

Laparoscopic radiofrequency ablation (LapRFA) is an established procedure for liver tumors in patients who are unsuitable for resection. A novel technique of magnetic resonance (MR) guided needle positioning during LapRFA was developed and compared to conventional ultrasound (US) guidance in a phantom model. MR-guided procedures were conducted in a 1.0 tesla high field open MR using an MR compatible endoscope and camera. The ultrasound-guided procedure was performed with a clinically established laparoscopy setup and a 2D laparoscopic US probe. During both techniques an identical monopolar non-ferromagnetic RFA needle and a silicon-based phantom model were applied. Finally needle positioning was performed by two surgeons and one interventionalist. Time to needle placement and number of trials were recorded and statistically analyzed. MR-guided needle positioning under laparoscopic control was technically feasible. Average time to correct needle placement was 2' 6″ in the LapUS group and 1' 54″ in the MR group. The number of trials was 3.2 in the LapUS group and 2.6 in the MR group. Image quality was assessed by all participants. MR images showed a better tissue to tumor contrast and allowed an improved orientation due to multiplanar visualization. MR-guided laparoscopic RFA is a promising technique offering multiplanar needle positioning with high soft tissue contrast with immediate therapy control. In a phantom model it showed comparable results regarding needle positioning to the established technique of laparoscopic US guidance.

Treatment of benign colorectal strictures by temporary stenting with self-expanding stents.

BACKGROUND: The application of stents in benign colorectal strictures is considered controversial. The aim of the present study was to assess effectiveness and complications associated with colorectal stent placement in benign colorectal disease. PATIENTS AND METHODS: Fourteen patients with benign colorectal strictures who had undergone previous surgery (colorectal anastomotic stenosis, 13; neosphincter scar stenosis, one) were treated with covered self-expanding metal stent or plastic stent. Placement of the stent was performed with combined endoscopy and contrast enhanced fluoroscopy. RESULTS: Self-expanding stents were successful implanted in all 14 patients without acute procedure-related complications. All patients experienced immediate decompression after stent placement with expansion and patency of the stent. Relief of bowel obstruction for at least 12 months was achieved in seven of 14 patients (50%). Anastomotic fistula healed in four of six patients (67%). Despite the initial success of stenting, re-operations had to be performed in two of seven patients because of late recurrence of the stricture after a mean follow-up of 37 months. CONCLUSIONS: Temporary insertion of self-expanding stents is a safe procedure that may be effective in selected cases of benign colorectal stricture. However, repeat surgery will be necessary in a considerable number of patients due to primary or secondary failure of stenting.

Hydroceles of the Canal of Nuck in Adults-Diagnostic, Treatment and Results of a Rare Condition in Females.

Nuck's hydroceles, which develop in a protruding part of the parietal peritoneum into the female inguinal canal, are rare abnormalities and a cause of inguinal swelling, mostly resulting in pain. They appear when this evagination of the parietal peritoneum into the inguinal canal fails to obliterate. Our review of the literature on this topic included several case reports and two case series that presented cases of Nuck hydroceles which underwent surgical therapy. We present six consecutive cases of symptomatic hydroceles of Nuck's canal from September 2016 to January 2020 at the Department of Surgery of Charité Berlin. Several of these patients had a long history of pain and consecutive consultations to outpatient clinics without diagnosis. These patients underwent laparoscopic or conventional excision and if needed simultaneous hernioplasty in our institution. Ultrasonography and/or Magnetic Resonance Imaging were used to display the cystic lesion in the inguinal area, providing the diagnosis of Nuck's hydrocele. This finding was confirmed intraoperatively and by histopathological review. Ultrasound and magnetic resonance imaging (MRI) captures, intraoperative pictures and video of minimal invasive treatment are provided. Nuck's hydroceles should be included in the differential diagnosis of an inguinal swelling. We recommend an open approach to external Type 1 Nuck´s hydroceles and a laparoscopic approach to intra-abdominal Type 2 Nuck hydroceles. Complex hydroceles like Type 3 have to be evaluated individually, as they are challenging and the surgical outcome is dependent on the surgeon's skills. If inguinal channel has been widened by the presence of a Nuck's hydrocele, a mesh plasty, as performed in hernia surgery, should be considered.

Does Hepatic Steatosis Influence the Detection Rate of Metastases in the Hepatobiliary Phase of Gadoxetic Acid-Enhanced MRI?

The aim of this exploratory study was to evaluate the influence of hepatic steatosis on the detection rate of metastases in gadoxetic acid-enhanced liver magnetic resonance imaging (MRI). A total of 50 patients who underwent gadoxetic acid-enhanced MRI (unenhanced T1w in- and opposed-phase, T2w fat sat, unenhanced 3D-T1w fat sat and 3-phase dynamic contrast-enhanced (uDP), 3D-T1w fat sat hepatobiliary phase (HP)) were retrospectively included. Two blinded observers (O1/O2) independently assessed the images to determine the detection rate in uDP and HP. The hepatic signal fat fraction (HSFF) was determined as the relative signal intensity reduction in liver parenchyma from in- to opposed-phase images. A total of 451 liver metastases were detected (O1/O2, n = 447/411). O1/O2 detected 10.9%/9.3% of lesions exclusively in uDP and 20.2%/15.5% exclusively in HP. Lesions detected exclusively in uDP were significantly associated with a larger HSFF (area under curve (AUC) of receiver operating characteristic (ROC) analysis, 0.93; p < 0.001; cutoff, 41.5%). The exclusively HP-positive lesions were significantly associated with a smaller diameter (ROC-AUC, 0.82; p < 0.001; cutoff, 5 mm) and a smaller HSFF (ROC-AUC, 0.61; p < 0.001; cutoff, 13.3%). Gadoxetic acid imaging has the advantage of detecting small occult metastatic liver lesions in the HP. However, using non-optimized standard fat-saturated 3D-T1w protocols, severe steatosis (HSFF > 30%) is a potential pitfall for the detection of metastases in HP.

Vascular Anomalies of the Extrahepatic Artery as a Predictable Risk Factor for Complications After Liver Transplant.

OBJECTIVES: Vascular variations of the extrahepatic artery occur in up to 50% of the population. Exact knowledge of any anomalies is of great significance in hepatobiliary surgery to avoid perioperative complications. In fact, in liver transplant, vascular complications are rare but have a major impact on graft function and survival. This study evaluated variations of the extrahepatic artery in donors and recipients as risk factors for vascular complications after liver transplant. MATERIALS AND METHODS: From January 2010 until June 2015, 469 liver transplant procedures were performed at our institution. We included 323 patients in our retrospective analysis after exclusion of retransplants, split-livertransplants, and pediatric patients. We analyzed the impact of anatomic variations of recipients and donors on postoperative vascular complications and organ and patient survival. RESULTS: Of total study recipients, 71.2% had a normal vascular supply according to Michel classification I. However, these patients developed significantly more vascular complications (25.65%) than those with vascular anomalies (15.05%), especially showing higher incidence of arterial stenosis (8.26% vs 2.15%). In contrast, vascular variations in donors and the need for a vascular reconstruction of the graft led to significantly higher mortality (26.76% vs 15.48%). An abnormality of the graft did not influence incidence of postoperative complications or graft survival. CONCLUSIONS: Unexpectedly, recipients with variations of the hepatic artery and grafts with an abnormal arterial supply did not show higher rates of com-plications or mortality. Only vascular reconstruction of the graft before transplant raised the mortality of recipients.

Impact of Doppler Ultrasound on Diagnosis and Therapy Control of Lienalis Steal Syndrome After Liver Transplantation.

BACKGROUND Lienalis steal syndrome is a rare complication after orthotopic liver transplantation leading to severe complications. Routine duplex sonography allows early and safe detection of lienalis steal syndrome and secondarily helps to monitor the outcome by evaluating the hemodynamics. MATERIAL AND METHODS This analysis included eight patients who after orthotopic liver transplantation needed splenic artery embolization due to lienalis steal syndrome. Lienalis steal syndrome was assumed in case of elevated transaminases, bilirubinemia or persistent ascites, and the absence of further pathologies. Diagnosis was supported by ultrasound, confirmed by digital subtraction angiography, and followed by splenic artery embolization for treatment. We analyzed blood levels and ultrasound findings before and after splenic artery embolization as well as during follow-up and evaluated for incidence of severe biliary complications and survival. RESULTS Arterial resistive index (RI) significantly regularized after splenic artery embolization while the maximum arterial velocity increased. The portal venous flow volume and maximum velocity decrease. Laboratory parameters normalized. Two of eight patients developed ischemic-type biliary disease. Survival rate was 88% over a median follow-up of 33 months. CONCLUSIONS Beside unspecific clinical findings, bedside ultrasound examination enabled a quick verification of the diagnosis and allowed direct treatment to minimize further complications. Furthermore, ultrasound can immediately monitor the therapeutic effect of splenic artery embolization.

Risk of local failure after ultrasound guided irreversible electroporation of malignant liver tumors.

INTRODUCTION: Irreversible electroporation (IRE) is considered superior to thermoablations for tumors in the vicinity of larger vessels and the liver hilum. We report on an initial clinical experience of IRE. MATERIALS AND METHODS: Indications included focal liver lesions <3 cm, irresectability due to contraindications and expected complications and/or irradicality following radiofrequency ablation (RFA). Ultrasound was chosen for guidance and needle placement. RESULTS: IRE was intended to perform in 14 patients with 1 procedure aborted due to technical failure. Among the 13 successfully treated were 7 percutaneous, 4 laparoscopic, and 2 open surgical procedures. The average age was 63 ± 10 years. Twelve solitary nodules and one bifocal disease were treated with an average size of 1.5 cm ± 0.5 cm. Median follow-up was 6 months. Three incomplete ablations account for 21% (3/14), 2 of them occurring in 2 metastases larger than 2 cm percutaneously treated with 5 needles instead of 4 used for smaller tumor sizes. CONCLUSION: IRE was introduced without difficulties into clinical practice. As a main obstacle emerged in visualization of the needles, computed tomography may offer advantages in the guidance of percutaneous IRE of liver metastases larger than 2 cm. Local failure occurred in 21%.

Postoperative immunosuppression after open and laparoscopic liver resection: assessment of cellular immune function and monocytic HLA-DR expression.

BACKGROUND AND OBJECTIVES: Major abdominal procedures are strongly associated with postoperative immunosuppression and subsequent increased patient morbidity. It is believed that laparoscopic surgery causes less depletion of the systemic immune function because of the reduced tissue trauma. Various cytokines and monocytic HLA-DR expression have been successfully implemented to assess postoperative immune function. The aim of our study was to show the difference in immunologic profiles after minimally invasive versus conventional liver resection. METHODS: Ten animals underwent either laparoscopic or conventional open left lateral liver resection. Flow cytometric characteristics of HLA-DR expression on monocytes and lipopolysaccharide-stimulated cellular secretion of tumor necrosis factor α, interferon γ, interleukin 6, and interleukin 8 were measured and analyzed in ex vivo whole blood samples. Intraoperative and postoperative clinical outcome parameters were also documented and evaluated. RESULTS: All animals survived the procedures. Postoperative complications were fever (n = 3), wound infections (n = 2), and biloma (n = 1). Open surgery showed a morbidity rate of 80% compared with 40% after laparoscopic surgery. Laparoscopic liver resection showed no postoperative immunoparalysis. Major histocompatibility complex class II expression in this group was elevated, whereas the open surgery group showed decreased major histocompatibility complex class II expression on postoperative day 1. Postoperative secretion of tumor necrosis factor , interleukin 6, and interferon was lower in the open surgery group. Elevated transaminase levels after laparoscopy might have resulted from an ischemia/reperfusion injury caused by the capnoperitoneum. CONCLUSION: Major immunoparalysis depression was not observed in either group. Laparoscopic surgery shows a tendency to improve immunologic recovery after liver resection.

Contrast enhanced ultrasound cholangiography via T-tube following liver transplantation.

BACKGROUND: The objective was to evaluate contrast enhanced ultrasound (CEUS) based cholangiography compared to conventional radiography as a reference method in patients after liver transplantation. MATERIAL/METHODS: Contrast agents were administered through T-tubes, which were placed during the operation. Twelve patients with side-to-side choledocho-choledochostomy and standardized intraoperative T-tube placement were investigated on the 5th postoperative day (POD 5) with both techniques. All images were digitally acquired and assessed in consensus by two investigators regarding complete anatomic visualization, depiction of pathology (e.g. delayed contrast outflow, stenosis and leakage) and general image quality. RESULTS: CEUS cholangiography showed comparable results in the detection of biliary pathology and overall image quality. Regarding the visualization of the extrahepatic bile duct CEUS produced limited results in 6 patients. CONCLUSIONS: In conclusion, CEUS cholangiography via T-tube represents a potential bedside test for visualization of intrahepatic bile ducts of transplanted livers; its diagnostic value remains to be determined in further studies.

A signal-inducing bone cement for magnetic resonance imaging-guided spinal surgery based on hydroxyapatite and polymethylmethacrylate.

The aim of this study was to develop a signal-inducing bone cement for magnetic resonance imaging (MRI)-guided cementoplasty of the spine. This MRI cement would allow precise and controlled injection of cement into pathologic lesions of the bone. We mixed conventional polymethylmethacrylate bone cement (PMMA; 5 ml methylmethacrylate and 12 g polymethylmethacrylate) with hydroxyapatite (HA) bone substitute (2-4 ml) and a gadolinium-based contrast agent (CA; 0-60 µl). The contrast-to-noise ratio (CNR) of different CA doses was measured in an open 1.0-Tesla scanner for fast T1W Turbo-Spin-Echo (TSE) and T1W TSE pulse sequences to determine the highest signal. We simulated MRI-guided cementoplasty in cadaveric spines. Compressive strength of the cements was tested. The highest CNR was (1) 87.3 (SD 2.9) in fast T1W TSE for cements with 4 µl CA/ml HA (4 ml) and (2) 60.8 (SD 2.4) in T1W TSE for cements with 1 µl CA/ml HA (4 ml). MRI-guided cementoplasty in cadaveric spine was feasible. Compressive strength decreased with increasing amounts of HA from 46.7 MPa (2 ml HA) to 28.0 MPa (4 ml HA). An MRI-compatible cement based on PMMA, HA, and CA is feasible and clearly visible on MRI images. MRI-guided spinal cementoplasty using this cement would permit direct visualization of the cement, the pathologic process, and the anatomical surroundings.

Management of esophageal anastomotic leaks, perforations, and fistulae with self-expanding plastic stents.

OBJECTIVE: Esophageal anastomotic leaks, perforations, and fistulae are associated with considerable morbidity and mortality. The aim of the present study was to assess the efficacy of self-expanding plastic stents in the treatment of esophageal leaks. METHODS: From 2001 to 2009, 41 patients with postoperative anastomotic leaks (n = 30), esophageal perforations (n = 6), or fistulae (n = 5) were treated by endoscopic insertion of self-expanding plastic stents. The clinical outcome of the patients was analyzed, including leak healing, morbidity, and mortality. RESULTS: Self-expanding plastic stents were successfully inserted in all 41 patients without procedure-related complications. Non-ventilated patients received oral feeding an average of 3.9 days after stent placement. Complete leak healing was obtained in 27 of 30 patients (90%) with anastomotic leaks and 5 patients (83%) with perforation. Sealing of fistulae by the stents was achieved in all 5 patients, and closure of the fistula was observed in 2 patients (40%). The mean healing time was 30 days for anastomotic leaks, 15 days for esophageal perforations, and 16 days for fistulae. Stent migration occurred in 14 cases, but endoscopic reintervention and new stent placement were successful in all cases. In-hospital mortality after treatment of esophageal leaks with stents was 10%. CONCLUSIONS: In combination with effective interventional or surgical drainage, stenting is a viable option for the treatment of esophageal anastomotic leaks and perforations, but the success in tracheoesophageal fistula is limited.

Esophageal stents for leaks and perforations.

Stenting of esophageal leaks, ie, anastomotic leaks or perforations, might be a minimally invasive alternative to surgery in most clinical situations. However, it must be emphasized that surgery should be considered if stent treatment in combination with drainage and antibiotics does not improve the clinical condition of the patient. Stent insertion should be performed as soon as possible after diagnosis of the leak.

Percutaneous transhepatic cholangiodrainage under real-time MRI guidance: initial experience in an animal model.

AIMS: To assess percutaneous transhepatic cholangiodrainage (PTCD) under real-time MRI-guidance and compare it to procedures performed under fluoroscopy. METHODS: We developed an in vitro model for MRI-guided and conventional PTCD, using an animal organ set including liver and bile ducts placed in an MRI-compatible box and tested it in a 1.0-Tesla open MRI-scanner. Prototype 18G needles and guide wires, standard guide wires, dilatation bougies, and drainages were used (MRI-compatible). MRI-visualization was by means of a bFFE real-time sequence using a surface coil (Flex-L). Outcome measurements were success rates and time needed for bile duct puncture using real-time MRI-guidance versus conventional radiologic methods in the model. Cannulation and drainage placement were also analysed. RESULTS: Fifty MRI-guided experiments were performed, leading to rapid (mean: 43s, range: 15-72s) and successful puncture and cannulation in 96% of procedures. Median drainage placement time was 321.5s (range: 241-411s). In 35 control experiments under fluoroscopy, puncture success was 69%, whereas times were significantly longer (mean 273s, range 45-631s). CONCLUSIONS: Initial in vitro experience shows that PTCD can be successfully and rapidly performed under real-time MRI-guidance and demonstrates improved performance compared to the conventional radiologic approach.