A study to compare strengths of cadaveric tendon repairs with round-bodied and cutting needles

This human cadaver study investigated whether flexor tendon repairs performed with round-bodied needles had a higher risk of pull-out compared with those performed with cutting needles. Forty human cadaver tendons were repaired (20 with each type of needle), subjected to tensile traction testing and evaluated by failure load and mode of failure. The average failure load was 50 N (SD 13 N) for tendons repaired with round-bodied needles, compared with 49 N (SD 16 N) for tendons repaired with cutting needles. Round-bodied needles resulted in more suture pull-out (18 out of 20 tendons) than cutting needles (6 out of 20 tendons). We found no differences in failure load, but significant differences in the mode of failure between round-bodied and cutting needles when used for cadaveric flexor tendon repair.

Bacterial Communities Associated with Human Decomposition

<p>Human decomposition is a little-understood process with even less currently known about the microbiology involved. The aim of this research was to investigate the bacterial community associated with exposed decomposing mammalian carcasses on soil and to determine whether changes in this community could potentially be used to determine time since death in forensic investigations. A variety of soil chemistry and molecular biology methods, including molecular profiling tools T-RFLP and DGGE were used to explore how and when bacterial communities change during the course of a decomposition event. General bacterial populations and more specific bacterial groups were examined. Decomposition was shown to cause significant and sequential changes in the bacterial communities within the soil, and changes in the bacterial community often correlated with visual changes in the stage of decomposition. Organisms derived from the cadavers and carcasses were able to be detected, using molecular methods, in the underlying soil throughout the decomposition period studied. There was little correlation found between decomposition stage and the presence and diversity within the specific bacterial groups investigated. Organisms contributing to the changes seen in the bacterial communities using molecular profiling methods were identified using a cloning and sequencing based technique and included soil and environment-derived bacteria, as well as carcass or cadaver-derived organisms. This research demonstrated that pig (Sus scrofa) carcass and human cadaver decomposition result in similar bacterial community changes in soil, confirming that pig carcasses are a good model for studying the microbiology of human decomposition. The inability to control for differences between donated human cadavers made understanding the human cadaver results difficult, whereas pig carcass study allowed many variables to be held constant while others were investigated. The information gained from this study about the bacteria associated with a cadaver and how the community alters over the course of decomposition may, in the future, enable the development of a forensic post mortem interval estimation tool based on these changes in the bacterial community over time. The findings in this thesis suggest that high variability between human bodies and their microflora is likely to present a challenge to the development of such a tool, but further study with emerging high-throughput molecular tools may enable identification of microbial biomarkers for this purpose.</p>

Bacterial Communities Associated with Human Decomposition

<p>Human decomposition is a little-understood process with even less currently known about the microbiology involved. The aim of this research was to investigate the bacterial community associated with exposed decomposing mammalian carcasses on soil and to determine whether changes in this community could potentially be used to determine time since death in forensic investigations. A variety of soil chemistry and molecular biology methods, including molecular profiling tools T-RFLP and DGGE were used to explore how and when bacterial communities change during the course of a decomposition event. General bacterial populations and more specific bacterial groups were examined. Decomposition was shown to cause significant and sequential changes in the bacterial communities within the soil, and changes in the bacterial community often correlated with visual changes in the stage of decomposition. Organisms derived from the cadavers and carcasses were able to be detected, using molecular methods, in the underlying soil throughout the decomposition period studied. There was little correlation found between decomposition stage and the presence and diversity within the specific bacterial groups investigated. Organisms contributing to the changes seen in the bacterial communities using molecular profiling methods were identified using a cloning and sequencing based technique and included soil and environment-derived bacteria, as well as carcass or cadaver-derived organisms. This research demonstrated that pig (Sus scrofa) carcass and human cadaver decomposition result in similar bacterial community changes in soil, confirming that pig carcasses are a good model for studying the microbiology of human decomposition. The inability to control for differences between donated human cadavers made understanding the human cadaver results difficult, whereas pig carcass study allowed many variables to be held constant while others were investigated. The information gained from this study about the bacteria associated with a cadaver and how the community alters over the course of decomposition may, in the future, enable the development of a forensic post mortem interval estimation tool based on these changes in the bacterial community over time. The findings in this thesis suggest that high variability between human bodies and their microflora is likely to present a challenge to the development of such a tool, but further study with emerging high-throughput molecular tools may enable identification of microbial biomarkers for this purpose.</p>

Fusion of Technology in Cochlear Implantation Surgery: Investigation of Fluoroscopically Assisted Robotic Electrode Insertion

The HEARO cochlear implantation surgery aims to replace the conventional wide mastoidectomy approach with a minimally invasive direct cochlear access. The main advantage of the HEARO access would be that the trajectory accommodates the optimal and individualized insertion parameters such as type of cochlear access and trajectory angles into the cochlea. To investigate the quality of electrode insertion with the HEARO procedure, the insertion process was inspected under fluoroscopy in 16 human cadaver temporal bones. Prior to the insertion, the robotic middle and inner ear access were performed through the HEARO procedures. The status of the insertion was analyzed on the post-operative image with Siemens Artis Pheno (Siemens AG, Munich, Germany). The completion of the full HEARO procedure, including the robotic inner ear access and fluoroscopy electrode insertion, was possible in all 16 cases. It was possible to insert the electrode in all 16 cases through the drilled tunnel. However, one case in which the full cochlea was not visible on the post-operative image for analysis was excluded. The post-operative analysis of the electrode insertion showed an average insertion angle of 507°, which is equivalent to 1.4 turns of the cochlea, and minimal and maximal insertion angles were recorded as 373° (1 cochlear turn) and 645° (1.8 cochlear turn), respectively. The fluoroscopy inspection indicated no sign of complications during the insertion.