MR-gesteuerter fokussierter Ultraschall

Standard radiological methods

High-intensity focused ultrasound (synonyms FUS and HIFU) under magnetic resonance imaging (MRI) guidance (synonyms MRgFUS and MR-HIFU) is a completely non-invasive technology for accurate thermal ablation of a target tissue while neighboring tissues and organs are preserved.

Methodical innovations

The combination of FUS with MRI for planning, (near) real-time monitoring and outcome assessment of treatment markedly enhances the safety of the procedure.

Achievements

The MRgFUS procedure is clinically established in particular for the treatment of symptomatic uterine fibroids, followed by palliative ablation of painful bone metastases. Furthermore, promising results have been shown for the treatment of adenomyosis, malignant tumors of the prostate, breast and liver and for various intracranial applications, such as thermal ablation of brain tumors, functional neurosurgery and transient disruption of the blood-brain barrier.     

Transanal endoscopic excision of rectal adenomas

Transanal endoscopic microsurgery (TEM) is a minimally invasive surgical technique for performing local excision of rectal lesions in the mid and upper rectum that would otherwise be inaccessible for local excision by the direct transanal approach. In the absence of this approach, low anterior resection would be required, which is major abdominal surgery. The justification for excising adenomas of the colon and rectum is their malignant potential, which correlates with the size of the lesion. This retrospective review examines our experience using TEM for excision of adenomas of the rectum from February 1991 to the present. The decision for using TEM is based on a precise localization of the lesion with particular attention to the upper margin of the lesion and its diameter. A total of 56 adenomas were removed. The average diameter was 4.9 cm (range, 3–8 cm). The average distance from the anal verge was 7.92 cm (range, 5–12 cm). Carcinoma in situ was seen in 7 lesions, and the remaining lesions were benign. Morbidity was minimal, with one conversion to an open procedure for an intraperitoneal perforation that required a low anterior resection. No patient required transfusion and there was no mortality. The hospital stay was short, with half of the patients being discharged the same day. The average cost from July 1996 to December 1999 was $7775 for TEM versus $34,018 for LAR. Subsequent follow-up average was 38.8 months (range, 1–100 months), during which time two patients had recurrence of their adenomas. This was successfully treated with reexcision. In conclusion, TEM is an accurate, safe, and relatively inexpensive technique when compared to low anterior resection. This technique significantly reduces the proportion of adenomas requiring abdominal surgery.     

Elevated levels of HER-2/neu and androgen receptor in clinically localized prostate cancer identifies metastatic potential

BACKGROUND: In this study, we investigated the expression of HER-2/neu and AR in clinically organ-confined prostate cancer to determine whether alterations in these signaling pathways contribute to the development of metastatic disease. METHODS: HER-2/neu and AR immunoreactivity were evaluated in archived prostatic tissues obtained from 53 men with clinically organ-confined disease who underwent radical prostatectomy. Associations between AR and HER-2/neu immunostaining and disease outcome were determined. RESULTS: Seventy percent (37/53) of tumors exhibited high levels of HER-2/neu immunostaining and 68% (36/53) of tumors had elevated AR levels. Patients with high levels of both HER-2/neu and AR had the highest rate of PSA failure (56%, 15/27) compared with no PSA failures amongst seven patients with low levels of both HER-2/neu and AR (log rank statistic 7.69, P = 0.021). Concurrent high levels of HER-2/neu and AR expression were significantly associated with high pathological stage (P = 0.027) and development of metastatic disease (P = 0.022). CONCLUSIONS: These findings support the notion that both the HER-2/neu and AR signaling pathways may contribute to development of metastatic disease. The subset of prostate tumors with increased HER-2/neu and AR levels may benefit from treatment strategies that target both signaling pathways.     

Synergistic Deposition of C4d by Complement-Activating and Non-activating Antibodies in Cardiac Transplants

The role of non-complement-activating alloantibodies in humoral graft rejection is unclear. We hypothesized that the non-complement-activating alloantibodies synergistically activate complement in combination with complement-activating antibodies. B10.A hearts were transplanted into immunoglobulin knock out (Ig-KO) mice reconstituted with monoclonal antibodies to MHC class I antigens. In allografts of unreconstituted Ig-KO recipients, no C4d was detected. Similarly, reconstitution with IgG1 or low dose IgG2b alloantibodies did not induce C4d deposition. However, mice administered with a low dose of IgG2b combined with IgG1 had heavy linear deposits of C4d on vascular endothelium. C4d deposits correlated with decreased graft survival. To replicate this synergy in vitro, mononuclear cells from B10.A mice were incubated with antibodies to MHC class I antigens followed by incubation in normal mouse serum. Flow cytometry revealed that both IgG2a and IgG2b synergized with IgG1 to deposit C4d. This synergy was significantly decreased in mouse serum deficient in mannose binding lectin (MBL) and in serum deficient in C1q. Reconstitution of MBL-A/C knock out (MBL-KO) serum with C1q-knock out (C1q-KO) serum reestablished the synergistic activity. This suggests a novel role for non-complement-activating alloantibodies and MBL in humoral rejection.     

Natural language processing and entrustable professional activity text feedback in surgery: A machine learning model of resident autonomy

BackgroundEntrustable Professional Activities (EPAs) contain narrative ‘entrustment roadmaps’ designed to describe specific behaviors associated with different entrustment levels. However, these roadmaps were created using expert committee consensus, with little data available for guidance. Analysis of actual EPA assessment narrative comments using natural language processing may enhance our understanding of resident entrustment in actual practice.MethodsAll text comments associated with EPA microassessments at a single institution were combined. EPA—entrustment level pairs (e.g. Gallbladder Disease—Level 1) were identified as documents. Latent Dirichlet Allocation (LDA), a common machine learning algorithm, was used to identify latent topics in the documents associated with a single EPA. These topics were then reviewed for interpretability by human raters.ResultsOver 18 months, 1015 faculty EPA microassessments were collected from 64 faculty for 80 residents. LDA analysis identified topics that mapped 1:1 to EPA entrustment levels (Gammas >0.99). These LDA topics appeared to trend coherently with entrustment levels (words demonstrating high entrustment were consistently found in high entrustment topics, word demonstrating low entrustment were found in low entrustment topics).ConclusionsLDA is capable of identifying topics relevant to progressive surgical entrustment and autonomy in EPA comments. These topics provide insight into key behaviors that drive different level of resident autonomy and may allow for data-driven revision of EPA entrustment maps.     

Removal of contrast media by different extracorporeal treatments.

BACKGROUND: Although the capability of extracorporeal treatments after administration of contrast media to prevent radiocontrast-induced nephropathy is controversial, haemodialysis is performed in many institutions after radiographic procedures. There are conflicting reports on the efficacy of different dialysers and treatment modalities to remove contrast media. METHODS: We compared the contrast medium-removing ability of different extracorporeal treatments in a randomized trial. Thirty-nine patients on chronic renal-replacement therapy or with chronic renal failure were randomized to receive low-flux haemodialysis (Low-HD, n=10), high-flux haemodialysis (High-HD, n=10), online haemodiafiltration (HDF, 10 litre substitution, n=10) and online haemofiltration (HF, 18 litre substitution, n=9) after administration of contrast medium during routine radiological procedures. Plasma concentrations of contrast medium (iopromide or iomeprol) were measured by energy-dispersive X-ray fluorescence analysis. RESULTS: The extraction ratio for contrast media was 0.64+/-0.1 for Low HD (P<0.05 vs. High-HD and vs. HDF), 0.74+/-0.1 for High-HD (P<0.05 vs. HF), 0.81+/-0.1 for HDF (P<0.05 vs HF), and 0.62+/-0.1 for HF. Mean extracorporeal plasma clearances were 82+/-2 for Low-HD (P<0.05 vs. High-HD and vs HDF), 100+/-2 for High-HD, 115+/-4 for HDF (P<0.05 vs. HF), and 86+/-5 ml/min for HF. CONCLUSIONS: We conclude that HDF and High-HD remove contrast media more effectively than Low-HD and HF during the time of each treatment session. However, whether this is also true for the overall elimination of contrast media by these different procedures needs to be addressed in future studies, by a precise assessment of the drug time course after the session.     

Compartment-specific expression and function of the chemokine IP-10/CXCL10 in a model of renal endothelial microvascular injury

The recruitment of inflammatory cells into renal tissue, mainly T cells and monocytes, is a typical feature of various renal diseases such as glomerulonephritis, thrombotic angiopathies, allograft rejection, and vasculitis. T cells predominantly infiltrate the tubulointerstitium, whereas monocytes are present in the tubulointerstitial and glomerular compartment. Because chemokines play a pivotal role in leukocyte trafficking under inflammatory conditions, this study investigated whether a differential expression of chemokines contributes to the precise coordination of leukocyte subtype trafficking in a rat model of renal microvascular endothelial injury. Renal microvascular endothelial injury was induced in rats by selective renal artery perfusion with an anti-endothelial antibody. Induction of the disease led to severe glomerular and tubulointerstitial endothelial injury with subsequent upregulation of chemokines followed by inflammatory cell recruitment. Among the analyzed chemokine mRNA, IP-10/CXCL10 (119-fold), acting via CXCR3 on activated T cells, and MCP-1/CCL2 (65-fold), acting via CCR2 on monocytes, were by far the most strongly upregulated chemokines. In situ hybridization revealed that IP-10/CXCL10 mRNA was selectively expressed by endothelial cells in the tubulointerstitial area, co-localizing with infiltrating T cells. Despite extensive damage of glomerular vasculature, no IP-10/CXCL10 expression by glomerular endothelial cells was detected. MCP-1/CCL2 mRNA in contrast was detectable in the glomerulus and the tubulointerstitium. Treatment with a neutralizing anti-IP-10/CXCL10 antibody significantly reduced the number of infiltrating tubulointerstitial T cells without affecting monocyte migration and led to an improved renal function. Our study demonstrates a role of IP-10/CXCL10 on T cell recruitment in a rat model of renal endothelial microvascular injury. Furthermore, a differential chemokine expression profile by endothelial cells in different renal compartments was found. These findings are consistent with the hypothesis that functional heterogeneity of endothelial cells from different vascular sites exists and provide an insight into the molecular mechanisms that may mediate compartment-specific T cell and monocyte recruitment in inflammatory renal disease.     

Why are patients still in hospital after fast-track,unilateral unicompartmental knee arthroplasty

Background and purpose — Previous studies have investigated risk factors related to prolonged length of stay following total knee arthroplasty (TKA), but little is known about specific factors resulting in continued hospitalization within the 1st postoperative days after unicompartmental knee arthroplasty (UKA). We investigated what specific factors prevent patients from being discharged on the day of surgery (DOS) and the first postoperative day (POD-1) following primary UKA in a fast-track setting.Patients and methods — We prospectively collected data on 100 consecutive and unselected medial UKA patients operated from December 2017 to May 2019. All patients were operated in a standardized fast-track setup with functional discharge criteria continuously evaluated from DOS and until discharge.Results — Median length of stay for the entire cohort was 1 day. 22% and 78% of all patients were discharged on DOS and POD-1, respectively. Lack of mobilization and pain separately delayed discharge in respectively 78% and 24% of patients on DOS. The main reasons for lack of mobilization were motor blockade (37%) and logistical factors (26%). For patients placed 1st or 2nd on the operating list, we estimate that the same-day discharge rate would increase to 55% and 40% respectively, assuming that pain and mobilization were successfully managed.Interpretation — One-fifth of unselected UKA patients operated in a standardized fast-track setup were discharged on DOS. Pain and lack of mobilization were the major reasons for continued hospitalization within the initial postoperative 24–48 hours. Strategies aimed at decreasing length of stay after UKA should strive to improve analgesia and postoperative mobilization.

The number of unicompartmental knee arthroplasties (UKAs) performed in patients suffering from osteoarthritis has steadily increased. UKA has the potential benefit of not only improving patient-reported outcomes, but also to reduce morbidity, complications, and cost (Liddle et al. 2014, Beard et al. 2019). In the United Kingdom, 9% of all primary knee arthroplasties performed in 2018 were UKAs while this number is as high as 20% in Denmark (Danish Knee Arthroplasty Register 2019, National Joint Registry for England 2019).UKA is effective and safe when performed in a fast-track setting and outpatient UKA in selected patients has been shown to be feasible and safe (Munk et al. 2012, Cross and Berger 2014, Bovonratwet et al. 2017, Kort et al. 2017). However, the number of patients actually being discharged on DOS that were scheduled for outpatient surgery differs between studies and ranges from 37% to 100% (Gondusky et al. 2014, Bradley et al. 2017, Jenkins et al. 2019, Rytter et al. 2019).Studies have shown an association between increased length of stay (LOS) and an increase in both complication and readmission rates (Otero et al. 2016). In order to reduce LOS and increase patient satisfaction, a focus on successfully managing well-defined discharge criteria in a multimodal approach is imperative (Husted et al. 2008, Cross and Berger 2014). In addition, decreased LOS and outpatient procedures are associated with financial benefits, which have further fueled interest in decreasing LOS and ensuring DOS discharged following UKA (Bradley et al. 2017). Finally, decreased LOS is also shown to increase patient satisfaction levels (Reilly et al. 2005, Richter and Diduch 2017).A study has been conducted to explore reasons for prolonged hospitalization in a fast-track setting following TKA (Husted et al. 2011). However, in spite of a growing number of UKAs performed each year, no study explicitly exploring reasons for prolonged hospitalization beyond DOS following UKA in a fast-track setting has been published at present.Therefore, we investigated reasons for continued hospitalization beyond DOS following UKA in a fast-track setting.     

Partial biliary obstruction caused by chronic pancreatitis. An appraisal of indications for surgical biliary drainage.

This paper presents a retrospective review of 38 patients with intrapancreatic bile duct strictures secondary to chronic alcoholic pancreatitis. The strictures were identified by endoscopic retrograde cholangiopancreatography (ERCP). All patients with pancreatic cancer and gallstone pancreatitis were excluded. The mean alkaline phosphatase and total bilirubin values were 344 +/- 57 IU/dl and 4.4 +/- 0.7 mg/dl, respectively. The mean stricture length was 3.9 +/- 0.5 cm, and the mean common bile duct (CBD) diameter was 1.8 +/- 0.2 cm. The degree of bilirubin and alkaline phosphatase elevation did not correlate with stricture length or the severity of bile duct dilatation. Eighteen of the 38 patients received surgical biliary drainage (BD) as part of their initial therapy, and 20 patients did not. Liver function tests, intrapancreatic stricture length, and the degree of proximal CBD dilation were comparable in these two groups. Patients not undergoing BD did well clinically as only one patient required BD over an average follow-up period of 3.8 years. In conclusion, bypass of these strictures is usually unnecessary, and most patients may be safely treated without operation.     

Stereopsis after primary in-the-bag posterior chamber implantation in children.

PURPOSE: The purpose of this study was to evaluate visual acuity and binocular function after primary posterior chamber intraocular lens (IOL) implantation in children. PATIENTS AND METHODS: A retrospective chart review of 39 eyes of 31 children was performed. Fifteen eyes with traumatic, 17 with developmental, and 7 with congenital cataracts without any other ophthalmologic problems were examined before and after cataract surgery (irrigation/aspiration procedure with implantation of a posterior chamber IOL). Twelve eyes also received a posterior capsulorrhexis and anterior vitrectomy. The mean age at surgery was 6.9 +/- 3 years (range, 3-12 years). RESULTS: Twenty (51%) of 39 eyes achieved a best-corrected postoperative visual acuity of 20/40 or better (range, 20/200-20/20). The mean postoperative visual acuity was 20/40 in the traumatic and developmental cataract groups and 20/100 in the congenital cataract group. There was a positive correlation between cataract morphology and visual acuity (P<.05). Bilateral cataracts had a better postoperative visual acuity than unilateral cataracts (P <.005). Nineteen (70%) of 27 eyes in which no primary posterior capsulorrhexis had been performed had posterior capsule opacification. Stereopsis was found in 10 of the 31 patients: 43% of the traumatic cataract group, 30% of the developmental cataract group, and 14% of the congenital cataract group. CONCLUSIONS: After capsular bag-fixated IOL, visual acuity and binocular function in children older than 3 years were favorable and the complication rate, excluding posterior capsule opacification, was low.