Microwave Physics

Contains reports on six research projects

Radio-Frequency Spectroscopy

Contains reports on four research projects

Microwave Physics

Contains reports on five research projects

The learning effect of intraoperative video-enhanced surgical procedure training

BACKGROUND: The transition from basic skills training in a skills lab to procedure training in the operating theater using the traditional master-apprentice model (MAM) lacks uniformity and efficiency. When the supervising surgeon performs parts of a procedure, training opportunities are lost. To minimize this intervention by the supervisor and maximize the actual operating time for the trainee, we created a new training method called INtraoperative Video-Enhanced Surgical Training (INVEST). METHODS: Ten surgical residents were trained in laparoscopic cholecystectomy either by the MAM or with INVEST. Each trainee performed six cholecystectomies that were objectively evaluated on an Objective Structured Assessment of Technical Skills (OSATS) global rating scale. Absolute and relative improvements during the training curriculum were compared between the groups. A questionnaire evaluated the trainee's opinion on this new training method. RESULTS: Skill improvement on the OSATS global rating scale was significantly greater for the trainees in the INVEST curriculum compared to the MAM, with mean absolute improvement 32.6 versus 14.0 points and mean relative improvement 59.1 versus 34.6% (P = 0.02). CONCLUSION: INVEST significantly enhances technical and procedural skill development during the early learning curve for laparoscopic cholecystectomy. Trainees were positive about the content and the idea of the curriculum

Correlation between radiological assessment of acute ankle fractures and syndesmotic injury on MRI

Item does not contain fulltextOBJECTIVE: Owing to the shortcomings of clinical examination and radiographs, injury to the syndesmotic ligaments is often misdiagnosed. When there is no indication requiring that the fractured ankle be operated on, the syndesmosis is not tested intra-operatively, and rupture of this ligamentous complex may be missed. Subsequently the patient is not treated properly leading to chronic complaints such as instability, pain, and swelling. We evaluated three fracture classification methods and radiographic measurements with respect to syndesmotic injury. MATERIALS AND METHODS: Prospectively the radiographs of 51 consecutive ankle fractures were classified according to Weber, AO-M�ller, and Lauge-Hansen. Both the fracture type and additional measurements of the tibiofibular clear space (TFCS), tibiofibular overlap (TFO), medial clear space (MCS), and superior clear space (SCS) were used to assess syndesmotic injury. MRI, as standard of reference, was performed to evaluate the integrity of the distal tibiofibular syndesmosis. The sensitivity and specificity for detection of syndesmotic injury with radiography were compared to MRI. RESULTS: The Weber and AO-M�ller fracture classification system, in combination with additional measurements, detected syndesmotic injury with a sensitivity of 47\% and a specificity of 100\%, and Lauge-Hansen with both a sensitivity and a specificity of 92\%. TFCS and TFO did not correlate with syndesmotic injury, and a widened MCS did not correlate with deltoid ligament injury. CONCLUSION: Syndesmotic injury as predicted by the Lauge-Hansen fracture classification correlated well with MRI findings. With MRI the extent of syndesmotic injury and therefore fracture stage can be assessed more accurately compared to radiographs

Surgical Simulator Design and Development

With the introduction of minimally invasive surgery (MIS), it became necessary to develop training methods to learn skills outside the operating room. Several training simulators have become commercially available, but fundamental research into the requirements for effective and efficient training in MIS is still lacking. Three aspects of developing a training program are investigated here: what should be trained, how it should be trained, and how to assess the results of training. In addition, studies are presented that have investigated the role of force feedback in surgical simulators. Training should be adapted to the level of behavior: skill-based, rule-based, or knowledge-based. These levels can be used to design and structure a training program. Extra motivation for training can be created by assessment. During MIS, force feedback is reduced owing to friction in the laparoscopic instruments and within the trocar. The friction characteristics vary largely among instruments and trocars. When force feedback is incorporated into training, it should include the large variation in force feedback properties as well. Training different levels of behavior requires different training methods. Although force feedback is reduced during MIS, it is needed for tissue manipulation, and therefore force application should be trained as well

Remediation of fluency: Word specific or generalised training effects?

The present study examines whether reading fluency benefits more from repeated reading of a limited set of words or from practicing reading with many different words. A group of 37 reading delayed Dutch children repeatedly read the same 20 words with limited exposure duration, whereas another group of 37 poor readers received the same reading exercises with 400 different words. Results demonstrated that improvements in accuracy and speed of trained words were larger for the repeated reading group than for the children who had only practiced with these words once. No difference in generalisation of effects to untrained neighbour and control words was found between the two conditions. Furthermore, rapid naming skill was unrelated to improvements in reading fluency and transfer effects in both training conditions. Results demonstrate that the practical value of repeated reading lies in its word specific training effects. © Springer 2006

Surface disorder production during plasma immersion implantation

Comparative investigations were performed using high-depth-resolution Rutherford backscattering (RBS) combined with channeling, spectroellipsometry (SE) and atomic force microscopy (AFM) to analyze surface disorder and surface roughness formed during plasma immersion implantation of silicon (100) substrates in a gas mixture containing PH3. In order to enhance the sensitivity to the determination of the oxygen content of the surface oxide layer, the 3.05 MeV (4He+, 4He+) nuclear resonance was used in combination with channeling. For the analysis of SE data we used the method in which an appropriate optical model is assumed and a best fit to the model parameters is obtained (i.e. the thickness of surface oxide and damaged silicon layers and the volume fraction of the components). Evaluation of RBS spectra yields damage profiles consistent with those obtained by SE modelling