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Background: There is a high prevalence of injury and low back pain prevalence associated with professional drivers, including mobile police officers. In particular, the reduction in lumbar lordosis has been hypothesized as a contributing risk factor for injury during prolonged seated periods. Furthermore, the use of the mobile data terminal (MDT) and the protective equipment worn by officers creates a unique interface between the occupant and the car seat. Purpose: To evaluate a novel thoracic support that was designed to address the unique seated working demands of mobile police officers. Methods: Fourteen participants: 7 male (21.3 (1.9) years, 1.71 (0.06) m, 75.1 (9.3) kg) and 7 female (23.3 (4.4) years, 1.69 (0.06) m, 68.2 (7.7) kg) were recruited from a university student population. Participants attended two 120 minute driving simulations on separate days; using a standard Crown Victoria Interceptor seat and the same seat equipped with a retrofitted surface mounted thoracic support. Time-varying spine postures, seat pressure measures and perceived discomfort were measured. Results: The introduction of a thoracic support changed postures, reduced lower seat back interface pressures but did not reduce discomfort compared to a standard seat during a 2 hour exposure period. Average discomfort scores were low with all values below 10mm out of a possible 100mm for both seating conditions. Discomfort was found to have small increases over time in the neck and right thigh with the support, but mean values remained low (under 3mm). Lumbar angles became more flexed with the support compared to a standard seat. Posterior pelvic rotation was reduced in female participants while in males there was greater posterior pelvic rotation with the support. There was a reduction in interface pressures on the bottom half of the seat back, the area where the duty belt is in contact with the seat. Conclusions: The postural and seat interface information support further field evaluations using a retrofitted thoracic insert as an in-vehicle ergonomic intervention for police officers. Further investigations focussed on prolonged exposure to the intervention will guide future design iterations.

Nucleus replacement has recently come into favor as a possible treatment for Degenerative Disc Disease. Replacing degenerative nucleus tissue with a synthetic material that mimics healthy nucleus tissue may restore normal function and biomechanics to the disc and delay or obviate the need for more invasive procedures such as total disc replacement and fusion. This thesis evaluated a novel protein polymer hydrogel composed of silk and elastin as a nucleus replacement material. There are three experimental components; one in vivo and two in vitro portions. In the first experimental portion, a large animal model was developed to evaluate the biocompatibility of the material as well as the effect on surrounding boney and soft tissues. Three discs were evaluated in each animal; sham, discectomy and discectomy treated with hydrogel. Discs were evaluated at 4, 26 and 52 weeks. The hydrogel group showed a quiet cellular response, as well as decreased boney remodeling and fewer degenerative changes when compared to the discectomy group. The second experimental portion evaluated the biomechanics of 9 cadaveric motion segments loaded in axial rotation, lateral bending, flexion/extension (FE) and compression. Specimens were tested sequentially in the intact state, following annulotomy, discectomy and after hydrogel treatment. Range of Motion (ROM) in FE was shown to increase from the intact state (8.50+/-1.44˚) to the discectomy state (9.86+/-1.77˚) and decrease following hydrogel treatment (8.66+/-0.76˚) to be similar to the intact ROM. The third experimental portion investigates the effect of three commonly applied testing conditions on the mechanical properties of spinal segments. 27 motion segments were tested at 18˚C wrapped with Phosphate Buffered Saline (PBS), at 37˚C in a PBS bath, and at 37˚C and 100% humidity. Specimens were tested hourly for 6 hours. The heated conditions were shown to have lower stiffness and increased range of motion when compared 18 ˚C tests. Repeated testing with time increased neutral zone and ROM for all modes of bending. As tests are repeated over time, tissue properties change and may mask the ability of a nucleus replacement to restore biomechanics.

Thesis (Ph. D.)--University of Toronto, 2006. / Source: Dissertation Abstracts International, Volume: 67-06, Section: B, page: 3271. Includes bibliographical references.

Licentiatavhandling (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 6 uppsatser.

Thesis (MScIng)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Undergraduate honors paper--Mount Holyoke College, 2008. Dept of Biological Sciences. / Includes bibliographical references (leaves 45-47).

Thesis (Ph. D.)--Virginia Commonwealth University, 2007. / Prepared for: Dept. of Physical Therapy. Bibliography: leaves 127 - 142 . Also available online via the Internet.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 208-243). Also available in print.