Christoph T. Germer

A Prospective Randomized Study to Test the Transfer of Basic Psychomotor Skills From Virtual Reality to Physical Reality in a Comparable Training Setting

Objective:To test whether basic skills acquired on a virtual endoscopic surgery simulator are transferable from virtual reality to physical reality in a comparable training setting. Summary Background Data:For surgical training in laparoscopic surgery, new training methods have to be developed that allow surgeons to first practice in a simulated setting before operating on real patients. A virtual endoscopic surgery trainer (VEST) has been developed within the framework of a joint project. Because of principal limitations of simulation techniques, it is essential to know whether training with this simulator is comparable to conventional training. Methods:Devices used were the VEST system and a conventional video trainer (CVT). Two basic training tasks were constructed identically (a) as virtual tasks and (b) as mechanical models for the CVT. Test persons were divided into 2 groups each consisting of 12 novices and 4 experts. Each group carried out a defined training program over the course of 4 consecutive days on the VEST or the CVT, respectively. To test the transfer of skills, the groups switched devices on the 5th day. The main parameter was task completion time. Results:The novices in both groups showed similar learning curves. The mean task completion times decreased significantly over the 4 training days of the study. The task completion times for the control task on Day 5 were significantly lower than on Days 1 and 2. The experts’ task completion times were much lower than those of the novices. Conclusions:This study showed that training with a computer simulator, just as with the CVT, resulted in a reproducible training effect. The control task showed that skills learned in virtual reality are transferable to the physical reality of a CVT. The fact that the experts showed little improvement demonstrates that the simulation trains surgeons in basic laparoscopic skills learned in years of practice.

MR-guided interstitial laser-induced thermotherapy of hepatic metastasis combined with arterial blood flow reduction: technique and first clinical results in an open MR system.

The feasibility and safety of percutaneous laser‐induced thermotherapy (LITT) of liver metastases in an open low‐field magnetic resonance imaging (MRI) system combined with microsphere‐modulated blood flow reduction were tested. Nd:YAG laser therapy with an internally cooled laser applicator was performed under local anesthesia on 20 patients with 34 liver metastases. To increase the effectivenes of LITT, degradable starch microspheres were injected into the proper hepatic artery through an MR‐visible catheter initially inserted under fluoroscopy. Near real‐time imaging was used for positioning the laser applicator. A T1‐weighted gradient‐echo breath‐hold sequence was used for catheter localization and temperature monitoring. The volumes of the liver metastases and the thermonecroses were determined. MRI‐guided LITT could be performed in all patients with no clinically relevant complications. Intraprocedural imaging underestimated the extent of thermonecrosis. In conclusion, percutaneous LITT of liver metastases after injection of starch microspheres is both technically feasible and safe in an open MRI system. J. Magn. Reson. Imaging 2001;13:31–36.

Technology for In Situ Ablation by Laparoscopic and Image-Guided Interstitial Laser Hyperthermia

The technical requirements have been fulfilled for the reliable clinical application of laser-induced thermotherapy for treating liver tumors. Laparotomy as well as percutaneous and laparoscopic access modes are available for this method. Thus, laser-induced thermotherapy is a true minimally invasive procedure for treating liver metastases. Presently, it is not possible to make a final assessment on the prognostic value of laser-induced thermotherapy in the treatment of liver tumors. However, recently published data justify the scheduling of a randomized study comparing laser-induced thermotherapy with standard surgical liver resection. In this article, thermobiological and technical principles as well as the different types of application modes for this method are described. Copyright ©1998 by W B. Saunders Company

Die STARR-Operation zur Therapie des obstruktiven Defäkationssyndroms

Stapled transanal rectal resection (STARR) has become a well-evaluated surgical procedure for the treatment of outlet obstruction in the context of conservative refractory obstructed defaecation syndrome (ODS). The diagnosis of ODS needs to be objectified which can be best ensured by clinical scoring systems. Besides a general coloproctological examination, dynamic defecography represents the most important diagnostic procedure. Pelvic floor dyssynergia and slow transit constipation should always be taken into account for the differential diagnosis and for which the STARR procedure is generally contraindicated. Surgery is performed via a transanal approach using a full thickness rectal resection of either the ventral or dorsal proportion of the rectal wall in the PPH01 conventional procedure or circumferentially by monoblock resection in the contour transtar® procedure. Morbidity is best characterised by data of the European STARR registry which contains a total number of n = 2,838 consecutive patients. The overall morbidity rate was 36 % whereby urgency (20 %) and bleeding (5 %) were the most frequent complications. More favourable data have been published in single centre studies. Functional results are available with a follow-up of 1 year up to 68 months postoperatively. Response rates of up to 90 % were reported whereas recurrence rates were given with a maximum of 18 % at 68 months follow-up. In summary, the STARR procedure provides good functional results in conservative refractory outlet obstruction with minor morbidity and the outcome seems to remain stable in the long-term follow-up.

Prognostic value of nuclear survivin-expression in esophageal squamous cell carcinoma

Survivin, a new member of the family of apoptosis inhibitors, is expressed almost exclusively in proliferating cells, above all in cancers. Subcellular localisation and prognostic implications of the survivin protein have not yet been determined in oesophageal squamous cell carcinoma. The survival of 84 patients with oesophageal squamous cell carcinomas was correlated with the extent of immunohistochemical survivin expression in tumour cell nuclei. Tumours were scored positive when 45% cells stained positive. Patients were followed up for at least 5 years or until death. In normal oesophageal squamous cell epithelium, some cytoplasmic survivin expression was detected in the basal cells, whereas proliferating cells showed nuclear staining of survivin. Nuclear expression of survivin was also detected in 67 cancers (80%). The mean survival for patients of this group (28 months, range 20 – 36) was significantly less than that for patients without survivin expression in the tumour cell nuclei (108 months, range 62 – 154, P ¼ 0.003). Using univariate analysis, nuclear survivin expression (P ¼ 0.003), tumour depth (P ¼ 0.001), lymph node metastasis (P ¼ 0.003) and stage (Po0.001) were the best predictors of survival. In contrast, cytoplasmic survivin staining was noted in 53 (63%) tumours and had no prognostic relevance. In conclusion, the analysis of nuclear survivin expression identifies subgroups in oesophageal squamous cell cancer with favourable (survivin � ) or with poor prognosis (survivin + ). We suggest that the determination of nuclear survivin expression could be used to individualise therapeutic strategies in oesophageal squamous cell cancer in the future.

Stadiengerechte Therapie der akuten Divertikulitis anhand der neuen Klassifikation der Divertikelkrankheit

BACKGROUND In recent years, there has been a significant change in the treatment recommendations for acute diverticulitis. In order to provide the right treatment to the individual patient, it is therefore important to classify the stage of the disease accurately, after taking various aspects into consideration. METHODS Patients treated for acute diverticulitis in Würzburg University Hospital during 2010 to 2014 were included. Inclusion criteria were the presence of a computer tomography for disease classification. RESULTS More than half of the patients examined (n = 135, 52.9%) had acute uncomplicated diverticulitis on admission; 112 (43.2%) had a covered perforation (small paracolic abscess n = 63, 24,3%; large abscess n = 49, 18,9%) and 12 (4.6%) a free perforation. In a total of 150 (57.9%) patients, this was the first episode of diverticulitis, with a covered (66.1%) or a free perforation (75.0%) occurring at a higher than average rate as the first manifestation. Nearly two-thirds (66.4%, n = 168) of patients underwent sigmoid resection during follow-up. DISCUSSION AND CONCLUSION Despite current trends towards more conservative therapy of acute diverticulitis, sigmoid resection remains a corner stone of successful therapy throughout all types of acute diverticulitis. The indication of sigmoid resection nowadays requires profound knowledge of the individual prognosis for recurrent diverticulitis and quality of life.

Correlation of intrahepatic light and temperature distribution in laser-induced thermotherapy of liver tumors and liver tissue

For prediction of the effectiveness of laser-induced thermotherapy (LITT) of liver metastases and for the Planning of laser treatment it is indispensable to achieve knowledge about the intrahepatic light and temperature distribution in order to obtain data for an optimally adapted dosimetry. We evaluated the optical properties of normal and tumorous rabbit-liver ex-vivo using a double integrating sphere technique as well as a Monte-Carlo-simulation. These data were correlated with the measurement of the intrahepatic temperature ditrsibution in-vivo during LITT. In our study we were able to show a positive correlation between ex-vivo results of optical properties and in-vivo results in temperature distribution. The absorption coefficient and scattering coefficients were significantly smaller in tumor tissue than in normal liver. This resulted in a higher optical penetration depth of the laser light into the tumor tissue (p<0.01). Temperature measurement near the applicator was lower in tumor tissue, than that distant from the applicator (p<0.01) corresponding to a higher temperature penetration depth. Both, higher optical and thermal penetration depth in the tumorous tissue was correlated with a significant increase in coagulation volume after LITT.