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    Jochen Weitz

    Percutaneous large core biopsy of the breast with a 14-gauge needle, supported by sonographic and mammographic procedures, shows a high degree of safety during the collection for benign and malignant lesions. All malignant diagnoses (B 5)... more
    Percutaneous large core biopsy of the breast with a 14-gauge needle, supported by sonographic and mammographic procedures, shows a high degree of safety during the collection for benign and malignant lesions. All malignant diagnoses (B 5) with a portion of 44% (267/604) were confirmed surgically, whereby the typing with 79% and grading with 58% were congruent. In 3.3% (20/604), there was uncertainty (B 3 and B 4), with the necessity for further clarification by open biopsy. This was supported by the fact that in 10/16 operated cases carcinoma was found. In the B 2-category, with a portion of nearly 44% (264/604), four cases of cancer were verified--not due to a wrongly negative histology but to non-representative material. In 8.8% (53/604), a questionable representative histology (B 1) occurred, but no cancer was found after surgical intervention (n=7). The indication for surgery is not only the punch biopsy result, but additionally negative histology and suspect or malignant clinic...
    Percutaneous high speed large core biopsy (LCB) using a 14-gauge-needle, supported by sonographic procedures, is a safe and reliable method for the diagnosis of benign and malignant breast lesions in daily practice. All malignant... more
    Percutaneous high speed large core biopsy (LCB) using a 14-gauge-needle, supported by sonographic procedures, is a safe and reliable method for the diagnosis of benign and malignant breast lesions in daily practice. All malignant diagnoses (B5)--comprising 44 % (267/604) of cases--were confirmed by subsequent surgical biopsy. This indicates a positive predictive value of 100 %. Evidence for uncertain dignity in LCB (categories B3 and B4) was found in 3 % of our cases (20/604), requiring open breast surgery for further clarification. This is strongly supported by the fact that 22 % of B3 and 82 % of B4 cases were identified as carcinomas in subsequent surgery. In 9 % of our cases (53/604), histology was only questionably representative (category B1) without cancer in the follow-up. In the B2-category--which comprised nearly 44 % of all cases (n = 263)--the positive predictive value ranged at 2 %. For clinical investigation, mammography, breast ultrasound and LCB the sensitivity were ...
    The lack of surgeons will be a future major problem in patient care for multifaceted reasons. Niche specialties such as OMFS face an additional drawback because of the need for dual qualification. Special surgical training that gives... more
    The lack of surgeons will be a future major problem in patient care for multifaceted reasons. Niche specialties such as OMFS face an additional drawback because of the need for dual qualification. Special surgical training that gives students the opportunity to gain experience in the techniques of plastic-reconstructive surgery (PRS) has therefore been established to promote interest in OMFS. Two hands-on courses with 8 modules of 2 h for 10 students were established. Course modules included surgical techniques of PRS, such as local flaps in a complex facial defect on pig heads, and were supervised by two OMFS surgeons. The identical initial and final tests examined theoretical knowledge and practical skills. Questionnaires concerning basic demographic data, future career goals, and perception of surgical disciplines before and after the completion of the course were handed out. The 19 participating students (12 female, 7 male; median age 24 ± 2.24) were in their 8.31 ± 1.20 semester. Results of the tests showed improvement in knowledge following the courses (before 52.68 ± 12.64 vs. after 77.89 ± 11.37; p < 0.05). Based on the Likert scale, an increase in interest in a career in OFMS was observed (3.90 ± 1.18 vs. 2.72 ± 1.33; p < 0.05), but this was not so marked with regard to a career in a surgical discipline in general (1.93 ± 1.30 vs. 1.62 ± 1.19; p > 0.05). Perception of OMFS as a surgical discipline changed (3.68 ± 1.09 vs. 1.80 ± 0.64; p < 0.05). The following values also changed: students´ perception of PRS in OMFS (14 (74.68 %) vs. 5 (25.32 %); 19 (100 %) vs. 0 (0 %)), evaluation of PRS as a study subject for medical students (7 (36.84 %) vs. 12 (63.16 %); 19 (100 %) vs. 0 (0 %)), and the interest in an OMFS elective subject (6 (31.58 %) vs. 13 (68.42 %); 18 (94.74 %) vs. 1 (5.26 %)) and as a final clinical year subject (4 (21.05 %) vs. 15 (78.95 %); 14 (73.68 %) vs. 5 (26.32 %)). Hands-on courses with complex facial defects can be used to gain new professionals, even in niche specialties such as OMFS. Moreover, a hands-on course design, including innovative teaching methods and structured objective tests combined with a close student-teacher relationship and motivated instructors, is able to promote complex surgical skills in PRS.
    This paper describes a method for measuring the shape accuracy of a cylindrical hole which is created by means of an automatically power-controlled laser system using navigated control. In dental surgery, drills or mills are used for bone... more
    This paper describes a method for measuring the shape accuracy of a cylindrical hole which is created by means of an automatically power-controlled laser system using navigated control. In dental surgery, drills or mills are used for bone treatment. For most patients the use of these instruments is very inconvenient. Furthermore, the bone treatment with rotating instruments can lead to thermal necrosis. Using a laser system could be a good alternative for the patient. The utilization of a laser system could also facilitate bone treatment without any severe thermal damage. An optical navigation system can be used for a safer handling of a laser system. The position and the orientation of the laser handpiece relative to the patient can be calculated. Thereby, the laser can be automatically switched off, if the end of the laser beam does not hit the preoperative planned area. In order to measure the accuracy of such a laser system, we created several cavities in a phantom with a manual...
    Traditional surgical teaching is influenced by restrictive factors, such as financial pressures and ethical constraints. The teaching of surgical skills during a medical school education seems not to be robust enough at present, possibly... more
    Traditional surgical teaching is influenced by restrictive factors, such as financial pressures and ethical constraints. The teaching of surgical skills during a medical school education seems not to be robust enough at present, possibly resulting in stressful circumstance for surgical novices. However, the authors are convinced that practical training is fundamental for preparing medical students optimally for challenges in the operating theater and have, therefore, examined a novel method of teaching basic surgical skills to medical students. A total of 20 medical students received surgical skill training, which included theoretical lessons, working with ex vivo pig training models, and active participation in the operating theater. All the trainees took written tests and were rated in an Objective Structured Clinical Examination. Before and after training, the students completed a self-assessment form involving the choice of the correct surgical indication and the performance of surgical procedures. The students' performance in the written examination and in the Objective Structured Clinical Examination increased significantly after training (p ≤ 0.001). Furthermore, the evaluation of the self-assessment form revealed significant improvements in all categories (p ≤ 0.001). Our surgical training method appears to improve the surgical abilities of medical students and to increase their self-confidence with respect to surgical procedures. Therefore, the authors recommend the integration of this method into the medical school curriculum to prepare medical students well for surgical challenges.
    Differential diagnosis of osteoradionecrosis and bisphosphonate-related osteonecrosis of the jaw is primarily based on medical history, rather than pathogenesis or histopathology. This report aims to redress this shortcoming by... more
    Differential diagnosis of osteoradionecrosis and bisphosphonate-related osteonecrosis of the jaw is primarily based on medical history, rather than pathogenesis or histopathology. This report aims to redress this shortcoming by demonstrating the advantages of tetracycline bone fluorescence as an aid to characterize osteonecrosis entities according to differential histopathologies. Furthermore, this technique facilitates the means to determine extent of necrosis and to optimize surgical therapy. Two patients with extended osteonecrosis of the lower jaw (osteoradionecrosis or bisphosphonate-related osteonecrosis of the jaw) were treated with partial mandibulectomy. After preoperative administration of doxycycline for 10 days, bone fluorescence was monitored intraoperatively to determine the resection boundaries. Fluorescence analysis correlated well with the specific histopathologic features of the 2 osteonecrosis entities. Bone fluorescence was predominantly observed in the cortical bone and cancellous bone regions in osteoradionecrosis and bisphosphonate-related osteonecrosis of the jaw, respectively. Margins of the osteonecrosis (and the resection) could be determined under fluorescence guidance; however, bone bleeding did not correlate with bone fluorescence in both osteonecrosis entities. Given that viable but not necrotic bone displays tetracycline fluorescence, a notion that reflects the histopathology, more precise characterization of the 2 osteonecrosis types is enabled. Furthermore, even in extended cases of osteonecrosis requiring partial mandibulectomy, bone fluorescence helps to pinpoint the margins of resection and thus signifies an improvement of surgical therapy of extended osteonecrosis.
    Surgical debridement is the therapy of choice in advanced stages of bisphosphonate-related osteonecrosis of the jaws (BRONJ). However, the therapy is currently only loosely standardized because no suitable imaging modalities exist. This... more
    Surgical debridement is the therapy of choice in advanced stages of bisphosphonate-related osteonecrosis of the jaws (BRONJ). However, the therapy is currently only loosely standardized because no suitable imaging modalities exist. This study aims to redress this by exploring the suitability and reproducibility of applying a fluorescence-guided bone resection to patients with BRONJ. This prospective pilot study comprised 15 patients with 20 BRONJ lesions (only stages II and III) with a history of intravenous bisphosphonate treatment for metastatic bone diseases. Before surgical treatment, each patient received a 10-day administration of doxycycline. Fluorescence-guided resection of necrotic bone was performed by means of a certified fluorescence lamp. Success of the procedure was proclaimed if mucosal closure was observed and symptoms were absent 4 weeks postoperatively. The 4-week postoperative follow-up identified a mucosal closure in 17 of 20 BRONJ lesions (85%). These patients were free of any symptoms. Failure as defined by mucosal dehiscence and exposed bone was observed in 3 of 20 BRONJ lesions (15%). The success rate of this surgical regimen of BRONJ was respectable, and thus fluorescence-guided bone resection can be considered an effective treatment for stage II and stage III BRONJ. Furthermore, the reproducibility of the technique offers an opportunity to standardize the surgical therapy. Further studies are called for that compare the fluorescence-guided bone resection with conventional surgical approaches, as well as surgical versus conservative treatment in the early stages (stages 0 and I) of BRONJ.