Comparison of manual steering and steering via joystick of a flexible rhino endoscope

Flexible endoscopes are used in ENT surgery for examination tasks in cases wherever rigid endoscopes are unsuitable to reach certain positions in the nasal cavity. Until today they are steered by hand and no robotized system has been put into clinical practice. One qualification a robot manipulator system has to fulfill to be accepted is not to create new disadvantages compared to the conventional method in surgery. An important factor is the time needed to steer the new system compared to the time needed to steer the conventional system. In this article a robot manipulator system and an experiment are presented to compare the particular times test persons need to perform a certain task. This approach offers the possibility to benchmark the developed robot manipulator system and future systems for flexible rhino endoscopes.

Evaluation of an OSCE assessment tool for abdominal ultrasound courses

PURPOSE

The purpose of this study was the conception and evaluation of a standardized and reliable assessment tool in the OSCE format to measure the performance and practical skills of abdominal ultrasound users in PGME.

MATERIALS AND METHODS

The design, logistics, pacing and the choice of tested competencies of a rotating OSCE parcours, as well as the options for quality control using detailed checklists versus global rating scales and different approaches to the training of the involved raters are described. Over the last 15 years the parcours has undergone incremental improvement and has been used in final examinations of abdominal ultrasound courses with approximately 5000 medical students and 2000 residents and fellows. For evaluation, all item difficulties and discrimination coefficients of the individual stations and the reliability (Cronbach's alpha) were calculated for the last 626 assessments.

RESULTS

All 14 hands-on stations showed discrimination coefficients from 0.31 to 0.65 (mean 0.48; SD 0.09). The 13 diagram stations showed mean values of 0.50 (SD 0.16). Data analysis revealed mean homogeneous item difficulties of 0.78 (SD 0.02) and 0.62 (SD 0.04), respectively. Cronbach's alpha was 0.69 with five stations and reached values above 0.8 when more than 8 stations are combined in one parcours.

CONCLUSION

The homogeneous distribution of item difficulties provides an opportunity for designing different OSCE versions with different levels of reliability. Several options to adjust the cut-off values, the choice of the examined contents and factors that influence the examinees' acceptance of this assessment tool for PGME or CME ultrasound courses are discussed. Overall, the values of reliability and accuracy of this assessment tool are high enough to be used also for high-stakes examinations in the field of abdominal ultrasound.

Manual accuracy in comparison with a miniature master slave device--preclinical evaluation for ear surgery

Manual accuracy in microsurgery is reduced by tremor and limited access. A surgical approach through the middle ear also puts delicate structures at risk, while the surgeon is often working at an unergonomic position. At this point a micromanipulator could have a positive influence. A system was developed to measure "working accuracy", time and precision during manipulation in the middle ear. 10 ENT-surgeons simulated a perforation of the stapedial footplate on a modified 3D print of a human skull in a mock OR. Each trial was repeated more than 200 times aiming manually and using a micro-manipulator. Data of over 4000 measurements was tested and graphically processed. Work strain was evaluated with a questionnaire. Accuracy for manual and micromanipulator perforation revealed a small difference. Learning curves showed a stronger decrease both in deviation and time when the micromanipulator was used. Also a lower work strain was apparent. The micromanipulator has the potential as an aiding device in ear surgery.

[Intraoperative volumetry in ENT surgery. Objectivation of surgical success by the volume control system]

PROBLEM

At present no procedure exists to measure distances or volumes in endoscopic or otherwise limited surgical approaches directly and with high accuracy. Here a laser measuring system is evaluated for the first time as a clinical application in ENT surgery.

MATERIAL AND METHODS

The volume control system (VCS) measures with the help of automatic recognition of laser measuring points in the surgical situs. A lab test examines the accuracy and the precision at anatomically accurate paranasal sinus and tympanic cavity models under flexible endoscopic visualization. The true values are known in each case as calibrated distances. Thus 90 values were available for evaluation. The clinical trial serves as proof of the intraoperative applicability and includes 32 patients.

RESULTS

The measurements in the lab test resulted in an average deviation from the true value at a maximum of 7.1%. The precision was between 0.2 and 0.5 mm. In the clinical setting the system could be used in all 32 patients. Altogether 97 measured values could be included. The VCS functioned without system failures. The additional time required for setting up amounted to less than 2 min. The manageability of the flexible endoscope was reduced because of the length and the difficulty in controlling the adjustment. The additional intraoperative time required for collection of the measured values was less than 4 min in each case. Many results led to clinically relevant interpretations with intraoperative consequences.

DISCUSSION

The VCS shows for the first time an intraoperatively applicable measuring function for distances, surfaces and volumes. There is a multiplicity of meaningful applications in ENT and in other surgical disciplines. The available study has proved the concept.

[Swiss registry for TNF-alpha blockers in children and adolescents with rheumatological diseases]

We created a registry to evaluate long term outcome, efficacy and adverse events for children treated wit TNF-alpha inhibitors in Switzerland. 106 patients (68 female/38 male) were included. 61 patients were treated with Etanercept (Enbrel) and 45 with Infliximab (Remicade). Concomitant treatment at baseline included corticosteroids in 26% and Methotrexate in 75% of the patients. Subjective disease activity three months after initiation of TNF-alpha was better in 81%, worse in 4% and stable in 15% of the patients. In total 24 adverse events in 21 patients were reported. Treatment with TNF-alpha inhibitors seems to be safe and effective for children and adolescents with rheumatologic diseases.

[Virtual endoscopy of the nose and paranasal sinuses in real-time. Surgical planning system "Sinus endoscopy" (SPS-SE)]

PROBLEM

The aim of this study was the development and clinical evaluation of a new method for virtual endoscopy of the nose and paranasal sinuses.

MATERIAL AND METHODS

The surgical planning system "sinus endoscopy" (SPS-SE) was completely newly developed. The surfaces of the CT images are represented with direct volume rendering (raycasting) which allows a sufficiently high image repetition frequency with the movement of the virtual endoscopy and material effects for a natural appearance were added. Detail accuracy of the virtual illustrations was examined with the help of a picture-statistic comparison between optical and the virtual endoscopy. The evaluation of the system by the patients and physicians was made with a validated questionnaire.

RESULTS

The deviations from defined landmarks of virtual in comparison to optical endoscopy are between 1.4 mm and 11.1 mm. Manoeuvering the virtual endoscope was found to be better than with the optical endoscope but the important parameters for visualization were similar. The accuracy of volume rendering, the high variability of scaling of the anatomical borders and orientation were judged to be negative factors. Altogether there was a balanced opinion from the ENT surgeons but without exception patients judged the system positively.

DISCUSSION

This investigation proved the efficiency of SPS-SE for three-dimensional real time reconstruction of high-resolution CT data of the nose and paranasal sinuses. However, some modifications are necessary before introduction into routine use.

Collection and analysis of breath and breath condensate exhaled by feral pigeons (Columba livia) and chickens (Gallus domesticus)

Samples of exhaled breath and breath condensate were collected from 20 feral pigeons (Columba livia) while they were anaesthetised and intubated, and when they were kept unanaesthetised in an acrylic box. Samples were also collected from six chickens (Gallus domesticus) while they were kept in an acrylic box. The samples were analysed for pH, nitric oxide (NO), hydrogen peroxide and leukotriene B4. The volume of condensate collected from the pigeons was independent of bodyweight and significantly more (1.66 [0.64] ml/kg) was obtained while they were in the acrylic box than when they were intubated (0.87 [0.32] ml/kg). The mean volume collected from the chickens was 0.15 (0.06) ml/kg. Cooled samples had higher concentrations of NO than uncooled samples. The pH of the samples of condensate collected from birds in the acrylic box were significantly higher (7.9 [0.3]) than those from the intubated birds (5.3 [0.1]), and samples from the chickens had significantly higher pH values than samples from the pigeons (8.2 [0.2] v 7.9 [0.3]).

[Modified procedure for patient registration for navigation control instruments in ENT surgery]

PROBLEM

Surgical navigation and navigation-controlled instruments demand a robust and precise patient registration process. For navigation in the skull, a bite-splint-based registration method has been widely applied, which had to be manufactured by dental technicians. The additional cost and time could be avoided by directly using the manufactured imprint, which is prepared by the ENT surgeon in one step.

MATERIAL AND METHODS

This study examined the re-positioning accuracy for three silicon materials in a laboratory study with a 3D measuring device (Faro-arm) after several re-positioning cycles (simulating erosion) in comparison to the gold standard.

RESULTS

The mean deviation after two cycles was lower for all three materials compared to the gold standard. Only C-Silikon Optosil was better then the gold standard after all cycles and with a deviation of 0.17 mm it well below that of the conventional bite-splint (0.28 mm). The additional cost benefits of 10 euro per imprint compared to the bite-splint with >100 euro favor this material for clinical application.

CONCLUSIONS

As a consequence of this investigation Optosil was successfully used in 6 patients during the period from 01.09.2007 to 30.11.2007. The bite-splint was manufactured completely in the ENT department and could be used during the planning CT and surgery. The resulting accuracy corresponded to the experiences gained in previous surgery with a maximum deviation of 0.87 mm. The favorable ergonomic characteristics for patient and surgeon could be confirmed. As a result of this study this clinic now exclusively uses the procedure described in this article for bite-splint-based registration.

Adenosine A(1), A(2a), A(2b), and A(3) receptors in hematopoiesis. 2. Expression of receptor mRNA in resting and lipopolysaccharide-activated mouse RAW 264.7 macrophages

Expression of mRNA for adenosine receptor subtypes A(1), A(2a), A(2b), and A(3) in normal and lipopolysaccharide (LPS)-activated murine RAW 264.7 macrophages has been investigated using the method of quantitative real-time polymerase chain reaction. The results have shown a very low, unquantifiable expression of adenosine A(1) receptor mRNA in both normal and LPS-activated macrophages. The other three adenosine receptor mRNAs have been found to be expressed at various but always quantifiable levels. Activation of the macrophages by LPS induced upregulation of the expression of adenosine receptor A(2a) and A(2b) mRNA, whereas the expression of adenosine receptor A(3) mRNA was downregulated. Unstimulated macrophages exhibited a high expression of the A(2b) adenosine receptor mRNA. The findings are discussed from the point of view of the antiinflammatory and hematopoiesis-stimulating roles of the adenosine receptor signaling.

Adenosine A(1), A(2a), A(2b), and A(3) receptors in hematopoiesis. 1. Expression of receptor mRNA in four mouse hematopoietic precursor cells

Four mouse bone marrow or thymus cell populations, namely granulopoietic/monocytopoietic, erythropoietic, B-lymphopoietic, and T-lymphopoietic precursor cells have been assayed by RT-PCR technique for the presence and relative amounts of adenosine A(1), A(2a), A(2b), and A(3) receptor mRNA. It has been found that (i) all four populations studied express all four adenosine receptor subtypes, (ii) the A(1), receptor is the least expressed in all populations studied, (iii) the A(3) receptor is markedly expressed in the populations of granulopoietic/monocytopoietic and erythropoietic cells, (iv) the A(2a) receptor is markedly expressed in the populations of B-lymphopoietic and T-lymphopoietic cells, and v) the A(2b) receptor does not predominate in any of the precursor cells studied. Our data offer a new possibility for the assessment of the readiness of these cells to respond, by receptor-mediated mechanisms, to adenosine or its analogs present in the tissues as a result of endogenous processes and/or following their administration.

[Tumoral calcinosis in a child: a case report and review]

Tumoral calcinosis (Ct) is a rare pathology of unknown origin.We present the clinical, imaging ( including CT and MRI), surgical and pathology findings of Ct in a 9 year-old boy who presented with an incidental finding of a large elbow mass. The MR aspect of Ct has been reported only once and this case is the second description in a child. The association of Ct and dermatomyositis, as reported hereby, has also been described only once. With respect to treatment alternatives, we believe that it is important for radiologists to recognise this rare pathology in pediatric patients.

Ultrafiltered Pig Leukocyte Extract (UPLE, IMUNOR®) Potentiates Hematopoiesis–Stimulating Effects of G-CSFIn Vitroand Improves the Outcome of Treatment of Hematopoietic Radiation Damage in Mice with G-CSF

Ultrafiltered pig leukocyte extract (UPLE, Imunor), a heterogeneous mixture of low molecular weight (<10 kD) substances released from disintegrated pig leukocytes was tested from the point of view of its hematopoiesis-modulating activities using experiments in vitro and in vivo. Attention was focused especially on evaluation of the contingent ability of UPLE to potentiate the hematopoiesis-stimulating effects of recobinant human granulocyte colony-stimulating factor (G-CSF). Experiments in vitro revealed the capability of sera from mice administered UPLE perorally (p.o.) to stimulate proliferation of progenitor cells for granulocytes and macrophages (GM-CFC) in cultures of normal bone marrow cells. In addition, UPLE, as well as sera from mice given UPLE, added to the cultures in combination with G-CSF enhanced the numbers of GM-CFC significantly over those induced by sera after administration of either of the preparations alone. In in vivo experiments, UPLE was found to increase the counts of GM-CFC per femur and femoral bone marrow cellularity in sublethally irradiated mice when administered p.o. after irradiation in combination with G-CSF in comparison with the effects of G-CSF alone. These results indicate the possibility of using UPLE, a commercially available preparation, for treatment of hematopoietic suppression of various etiology.

[Performance-related middle management in medical teaching. Attractiveness of incentive tools from the perspective of the teachers]

BACKGROUND AND OBJECTIVE

German medical schools are increasingly challenged by the competition for public funds and talented students. Therefore. many curriculum planners, deans and school administrators plan to implement a systematic and comprehensive awarding system for good teaching. The OBJECTIVE of this study was to elaborate which specific incentives would be most effective to increase the motivation and enthusiasm for teaching among basic scientists as well as residents and attendings involved in medical education. In addition, a cost-effective model should be developed, which could be used as an adjustable blue-print for an awarding system.

METHODS

Based on literature search, existing approaches to rewards and incentives for medical teachers were analysed by an interdisciplinary committee in coordination with the members' department heads. According to german teaching methods and available resources, a catalogue of specific incentives has been designed and ranked by a representative sample of 200 medical teachers / faculty at two universities. Thus, a variety of favourite rewarding instruments could be elaborated, which were preferred by teachers in theoretical versus clinical disciplines.

RESULTS

The majority of the medical teachers prefer heterogeneously monetary incentives and additional protected time, followed by career-effective incentives (tenure & promotion). The discussion reflects on a transferable catalogue of different rewarding instruments, including a cost-/benefit-analysis and prerequisite students' evaluation data.

CONCLUSION

A single alteration of departmental teaching budgets does not seem to be sufficient. It seems rather advisable, also to strive for a variety of different incentives on a level that predominantly affects individual teaching personnel. Even with comparatively small amounts of money, significant effects on teachers' motivation can be achieved.

[Improvement of registration accuracy for navigated-control drill in mastoidectomy (autopilot)]

BACKGROUND

The goal of this study is the improvement of the surgical accuracy of a navigate-controlled drill for mastoidectomy in a lab test.

METHODS

For lab tests an artificial model of the temporal bone with color-coded injury identification of the facial nerve (solution of 0.5 mm) was used. Two different registration methods were examined: (group 1) navigation bow with 4 integrated markers at the upper jaw; (group 2) landmark registration with 4 titanium micro screws. An optical navigation system was used. The targets were illustrated by 3 titanium screws within the range of the planum mastoideum. The accuracy of the navigate-controlled drill in drilling the planned cavity were evaluated at 20 temporal bone models. The measurement of the registration accuracy was evaluated by deviation between the target screw and the calculated position in the navigation system. The evaluation of the resulted cavities was done by 5 senior surgeons with the help of the microscope.

RESULTS

The registration accuracy shows a maximum deviation between the real position and the calculated position of 1,73 MM in group of 1 and 0.93 MM in group 2. In group 1 the nerve was hurt in 5/20 cases and a maximum deviation of - 1.5 mm (Std 0.25 mm) (drilled beyond the nerve) was measured. In group 2 the nerve was not hurt, a maximum deviation of 0.5 mm (too early stopped before the nerve) was measured.

CONCLUSIONS

Significantly better results of the registration and drilling accuracy show up in group group 2. Thus the preconditions for clinical use are fulfilled.