Thomas Shiozawa

Cerebral representation of non-verbal emotional perception: fMRI reveals audiovisual integration area between voice- and face-sensitive regions in the superior temporal sulcus

Successful social interaction relies on multimodal integration of non-verbal emotional signals. The neural correlates of this function, along with those underlying the processing of human faces and voices, have been linked to the superior temporal sulcus (STS) in previous neuroimaging studies. Yet, recently it has been demonstrated that this structure consists of several anatomically defined sections, including a trunk section as well as two separate terminal branches, and exhibits a pronounced spatial variability across subjects. Using functional magnetic resonance imaging (fMRI), we demonstrated that the neural representations of the audiovisual integration of non-verbal emotional signals, voice sensitivity and face sensitivity are located in different parts of the STS with maximum voice sensitivity in the trunk section and maximum face sensitivity in the posterior terminal ascending branch. The audiovisual integration area for emotional signals is located at the bifurcation of the STS at an overlap of voice- and face-sensitive regions. In summary, our findings evidence a functional subdivision of the STS into modules subserving the processing of different aspects of social communication, here exemplified in human voices and faces and audiovisual integration of emotional signals from these sources and suggest a possible interaction of the underlying voice- and face-sensitive neuronal populations during the formation of the audiovisual emotional percept.

Computer-assisted periacetabular screw placement: Comparison of different fluoroscopy-based navigation procedures with conventional technique

The current gold standard for operatively treated acetabular fractures is open reduction and internal fixation. Fractures with minimal displacement may be stabilised by minimally invasive methods such as percutaneous periacetabular screws. However, their placement is a demanding procedure due to the complex pelvic anatomy. The aim of this study was to evaluate the accuracy of periacetabular screw placement assessing pre-defined placement corridors and comparing different fluoroscopy-based navigation procedures and the conventional technique. For each screw an individual periacetabular placement corridor was preoperatively planned using the planning software iPlan CMF(©) 3.0 (BrainLAB). 210 screws (retrograde anterior column screws, retrograde posterior column screws, supraacetabular ilium screws) were placed in an artificial Synbone pelvis model (30 hemipelves) and in human cadaver specimen (30 hemipelves). 2D- and 3D-fluoroscopy-based navigation procedures were compared to the conventional technique. Insertion time and radiation exposure to specimen were also recorded. The achieved screw position was postoperatively assessed by an Iso-C(3D) scan. Perforations of bony cortices or articular surfaces were analysed and the screw deviation severity (difference of the operatively achieved screw position and the preoperatively planned screw position in reference to the pre-defined corridors) was determined using image fusion. Using 3D-fluoroscopy-based navigation, the screw perforation rate (7%) was significantly lower compared to 2D-fluoroscopy-based navigation (20%). For all screws, the deviation severity was significantly lower using a 3D- compared to a 2D-fluoroscopy-based navigation and the conventional technique. Analysing the posterior column screws, the screw deviation severity was significantly lower using 3D- compared to 2D-fluoroscopy-based navigation. However, for the anterior column screw, the screw deviation severity was similar regardless of the imaging method. Despite the advantages of the 3D-fluoroscopy-based navigation, this method led to significantly longer total procedure and fluoroscopic times, and the applied radiation dose was significantly higher. Percutaneous periacetabular screw placement is demanding. Especially for posterior column screws, due to a lower perforation rate and a higher accuracy in periacetabular screw placement, 3D-fluoroscopy-based navigation procedure appears to be the method of choice for image guidance in acetabular surgery.

Three distinct fiber pathways of the bed nucleus of the stria terminalis to the amygdala and prefrontal cortex.

The bed nucleus of the stria terminalis (BNST) is an important relay for multiple cortical and subcortical regions involved in processing anxiety as well as neuroendocrine and autonomic responses to stress, and it is thought to play a role in the dysregulation of these functions as well as in addictive behavior. While its architecture and connection profile have been thoroughly examined in animals, studies in humans have been limited to post-mortem histological descriptions of the BNST itself, not accounting for the distribution of its various connections. In the current study, we used diffusion-weighted magnetic resonance imaging (DW-MRI) to investigate the courses of fiber tracks connected to the BNST in humans. We restricted our seed region for probabilistic fiber tracking to the dorsal part of the BNST, as the ventral BNST is not distinguishable from the surrounding grey matter structures using magnetic resonance imaging. Our results show two distinct pathways of the BNST to the amygdala via the stria terminalis and the ansa peduncularis, as well as connections to the hypothalamus. Finally, we distinguished a route to the orbitofrontal cortex (OFC) running through the head of the caudate nucleus (CN) and the nucleus accumbens (NAcc). Pathways to brainstem regions were found to show a considerable inter-individual variability and thus no common pathway could be identified across participants. In summary, our findings reveal a complex network of brain structures involved in behavioral and neuroendocrine regulation, with the BNST in a central position.

Nerve-preserving sacrocolpopexy: anatomical study and surgical approach

OBJECTIVE The aim of our study is to describe the course of the autonomic nerves in the presacral space and to find the best nerve-preserving approach for sacrocolpopexy. STUDY DESIGN The autonomic nerves of the presacral space were dissected on six specially preserved female cadavers. RESULTS The superior hypogastric plexus is located in front of the abdominal aorta and its bifurcation and deviates to the left of the midsagittal plane. At the level of the promontory, or just below, the superior hypogastric plexus branches into two hypogastric nerves that run in front of the sacrum. In the presacral space the parasympathetic pelvic splanchnic nerves from the ventral rami of the sacral spinal nerves (S2-S3) join the hypogastric nerves, forming the inferior hypogastric plexus on both sides. From the inferior hypogastric plexus, nerve fibres spread out bilaterally to the pelvic organs. In two of the six cadavers sacral splanchnic nerves could be identified leading from the sacral sympathetic ganglion S1 of the sympathetic trunk to the inferior hypogastric plexus. CONCLUSION Longitudinal incision of the peritoneum along the right common iliac artery and above the promontory allows for a safe approach for sacrocolpopexy. After exposing the vascular structure (e.g. medial sacral vessels) above the promontory, the anterior longitudinal ligament becomes visible and can be prepared for the fixation of the mesh for vaginal suspension. By protecting the superior hypogastric plexus and the part of the presacral area below the promontory we can preserve the hypogastric nerves, the sacral and pelvic splanchnic nerves and thus the autonomic innervation of the pelvic organs. Awareness of the course of the autonomic nerves in the presacral space will significantly improve the functional outcome of sacrocolpopexy and reduce bowel, urinary and sexual dysfunctions.

Development and implementation of a technical and didactical training program for student tutors in the dissection course.

BACKGROUND student tutors have a long tradition in gross anatomy instruction. However, the full potential of the tutors is generally not tapped, since little attention is paid to their technical and didactical training. The aim of this paper is to report a systematic approach to the development, didactic reasoning and implementation of a curriculum for training student tutors in gross anatomy. METHODS the training program was developed using the six-step approach of Kerns curriculum development model. For needs assessment, the literature research was amended by a survey among the 1st and 2nd year students of the dissection course (n=167) and two independent 90 min focus group interviews with the tutors who supervised these students (n=15). Protocols were transcribed and analyzed by margin coding. The training curriculum was setup on the basis of these data. RESULTS corresponding to the literature, the students want student tutors with good teaching competence as well as adequate content knowledge and technical competence. Supporting that, the tutors request a training program enhancing their didactic skills as well as their knowledge of content and working using relevant methods. Thus, a combined didactic and professional training program has been developed. Six professional and 11 didactic learning objectives were defined. A 3 weeks training curriculum was implemented, using microteaching and group exercises for didactics and active dissection for technical training. Both parts were interlocked on a contextual and practical level. CONCLUSION our focus group analyses revealed that a specific training program for student tutors in the dissection course is necessary. We describe a feasible task-oriented training curriculum combining didactic and professional objectives.

Anatomic study of prolapse surgery with nonanchored mesh and a vaginal support device

OBJECTIVE The purpose of this study was to evaluate the anatomic position and relations to neighboring neurovascular structures of polypropylene implants after vaginal repair with nonanchored mesh and a vaginal support device in a cadaver model. STUDY DESIGN We undertook anatomic dissection of 6 cadavers, with and without prolapse after surgery. RESULTS All polypropylene implants were positioned in accordance with the prescribed surgical technique. This surgery reconstructed the entire anterior and posterior pelvic floor compartments without extension beyond the pelvic cavity. A safe distance between the implants and their neighboring neurovascular structures (obturator nerve and vessels, 2.8-3.3 cm; pudendal nerve and internal pudendal vessels, 1.8-2.2 cm; sacral plexus, 2-2.2 cm) was observed. CONCLUSION Anatomic cadaver dissection confirmed the accurate and safe placement of the polypropylene implants with the use of the prescribed surgical technique.

Focused didactic training for skills lab student tutors - which techniques are considered helpful?

Objective: Peer-assisted learning is widely used in medical education. However, little is known about an appropriate didactic preparation for peer tutors. We herein describe the development of a focused didactic training for skills lab tutors in Internal Medicine and report on a retrospective survey about the student tutors’ acceptance and the perceived transferability of attended didactic training modules. Methods: The course consisted of five training modules: ‘How to present and explain effectively’: the student tutors had to give a short presentation with subsequent video analysis and feedback in order to learn methods of effective presentation. ‘How to explain precisely’: Precise explanation techniques were trained by exercises of exact description of geometric figures and group feedback. ‘How to explain on impulse’: Spontaneous teaching presentations were simulated and feedback was given. ‘Peyton’s 4 Step Approach’: Peyton‘s Method for explanation of practical skills was introduced and trained by the participants. ‘How to deal with critical incidents’: Possibilities to deal with critical teaching situations were worked out in group sessions. Twenty-three student tutors participated in the retrospective survey by filling out an electronic questionnaire, after at least 6 months of teaching experience. Results: The exercise ‘How to present and explain effectively’ received the student tutors’ highest rating for their improvement of didactic qualification and was seen to be most easily transferable into the skills lab environment. This module was rated as the most effective module by nearly half of the participants. It was followed by ‘Peyton’s 4 Step Approach’ , though it was also seen to be the most delicate method in regard to its transfer into the skills lab owing to time concerns. However, it was considered to be highly effective. The other modules received lesser votes by the tutors as the most helpful exercise in improving their didactic qualification for skills lab teaching. Conclusion: We herein present a pilot concept for a focused didactic training of peer tutors and present results of a retrospective survey among our skills lab tutors about the distinct training modules. This report might help other faculties to design didactic courses for skills lab student tutors.

Pull-out strength of cemented solid versus fenestrated pedicle screws in osteoporotic vertebrae

Objectives Cement augmentation of pedicle screws could be used to improve screw stability, especially in osteoporotic vertebrae. However, little is known concerning the influence of different screw types and amount of cement applied. Therefore, the aim of this biomechanical in vitro study was to evaluate the effect of cement augmentation on the screw pull-out force in osteoporotic vertebrae, comparing different pedicle screws (solid and fenestrated) and cement volumes (0 mL, 1 mL or 3 mL). Materials and Methods A total of 54 osteoporotic human cadaver thoracic and lumbar vertebrae were instrumented with pedicle screws (uncemented, solid cemented or fenestrated cemented) and augmented with high-viscosity PMMA cement (0 mL, 1 mL or 3 mL). The insertion torque and bone mineral density were determined. Radiographs and CT scans were undertaken to evaluate cement distribution and cement leakage. Pull-out testing was performed with a material testing machine to measure failure load and stiffness. The paired t-test was used to compare the two screws within each vertebra. Results Mean failure load was significantly greater for fenestrated cemented screws (+622 N; p ⩽ 0.001) and solid cemented screws (+460 N; p ⩽ 0.001) than for uncemented screws. There was no significant difference between the solid and fenestrated cemented screws (p = 0.5). In the lower thoracic vertebrae, 1 mL cement was enough to significantly increase failure load, while 3 mL led to further significant improvement in the upper thoracic, lower thoracic and lumbar regions. Conclusion Conventional, solid pedicle screws augmented with high-viscosity cement provided comparable screw stability in pull-out testing to that of sophisticated and more expensive fenestrated screws. In terms of cement volume, we recommend the use of at least 1 mL in the thoracic and 3 mL in the lumbar spine. Cite this article: C. I. Leichtle, A. Lorenz, S. Rothstock, J. Happel, F. Walter, T. Shiozawa, U. G. Leichtle. Pull-out strength of cemented solid versus fenestrated pedicle screws in osteoporotic vertebrae. Bone Joint Res 2016;5:419–426.

Development of a seminar on medical professionalism accompanying the dissection course

INTRODUCTION Medical professionalism is an increasingly important issue in medical education. The dissection course represents a profound experience for undergraduate medical students, which may be suitable to address competencies such as self-reflection and professional behavior. MATERIAL AND METHODS Based on a needs assessment, a seminar on medical professionalism was developed to parallel the dissection course. The conceptual framework for the teaching intervention is experiential learning. Specific learning goals and an interview guideline were formulated. After a pilot run, peer-teaching was introduced. RESULTS Over three terms (winter 2012/13, 2013/14, 2014/15), an average of 129 students voluntarily participated in the seminar, corresponding to 40% of the student cohort. The evaluation (n=38) shows a majority of students agreeing that the seminar offers support with this extraordinary situation in general and also that the seminar helps them to become first impressions on how to cope with death and dying in their later professional life as a doctor, and, that it also provides them the means to reflect upon their own coping mechanisms. CONCLUSION Although not yet implemented as an obligatory course, the seminar is appreciated and positively evaluated. Medical professionalism is an implicit aspect of the dissection course. To emphasize its importance, a teaching intervention to explicitly discuss this topic is advisable.

Fronto-temporal branch of facial nerve within the interfascial fat pad: is the interfascial dissection really safe?

BackgroundThe study was conducted to clarify the presence or absence of fronto-temporal branches (FTB) of the facial nerve within the interfascial (between the superficial and deep leaflet of the temporalis fascia) fat pad.MethodsEight formalin-fixed cadaveric heads (16 sides) were used in the study. The course of the facial nerve and the FTB was dissected in its individual tissue planes and followed from the stylomastoid foramen to the frontal region.ResultsIn the fronto-temporal region, above the zygomatic arch, FTB gives several small twigs running anteriorly in the fat pad above the superficial temporalis fascia and a branch within the temporo-parietal fascia (TPF) to the muscles of the forehead. There were no twigs of the FTB within the interfascial fat pad.ConclusionsNo branches of the FTB are found in the interfascial (between the superficial and deep leaflet of the temporalis fascia) fat pad. The interfascial dissection can be safely performed without risk of injury to the FTB and potential subsequent frontalis palsy.