The human wrist contains eight carpal bones in which the scaphoid plays a key role in carpal stability and mechanics. A scaphoid fracture is the most common carpal fracture. When healing of the fracture fails (nonunion), a specific pattern of osteoarthritis occurs, resulting in a carpal collapse. It is unknown how a scaphoid nonunion influences carpal kinematics and results into this carpal collapse. Until now, most research is done with the wrist in a steady state position. This thesis uses a new imaging technique: four-dimensional (4D)-CT imaging, which can analyze scaphoid kinematics during wrist motion. Part one of this thesis contains two reviews which addressed the main issues of the imaging techniques currently used in patients with a scaphoid nonunion.
This thesis gains insight into the alteration of biomechanics of the shoulder with shortening of the clavicle to understand what could be the cause of complaints around the shoulder with clavicle malunion. A retrospective study was performed into patient and fracture characteristics at the time of fracture. The biomechanical changes are evident. Shortening of the clavicle results in an altered position and motion tract of the scapula. Using these data in a computer model we could see that the changes of scapula position and motion would lead to less ability to generate force in certain movements of the shoulder.
This thesis is a research in tissue engineering of cartilage for the application of craniofacialsurgery such as in burn patients. In the lab, cartilage cells were cultured and a hydrogel to grow them in. The quality of this cartilage was studied and also the feasibility of printing cartilage cells, and the development of a shell to grow these cells in the shape of an ear. In the future, the goal is to engineer new pieces of cartilage for use in the clinic and to use these cartilage pieces in surgery for the reconstruction of damaged ears or noses. Direct 3D (bio)printing of cartilage will not become a mainstream therapy for a long time, if at all. However, the target is to develop small pieces of good quality cartilage to use for surgery.
Sarah Zandvliet (Amsterdam VUmc, location VUmc): Spontaneous neurobiological recovery and modulation of sensorimotor function after ischemic stroke. 29/10/2020 | 9.45 | Aula | Main Building | VU | To follw on You Tube. Supervisor: prof.dr. G. Kwakkel, co-supervisors: dr. E.E.H. van Wegen, dr. C.G.M. Meskers.
The majority of stroke patients show some level of motor recovery of the upper limb, mainly in the first 8-10 weeks. The variability in recovery and the reasons why approximately one third of stroke patients show very little to no recovery, are not well understood. An accurate individual prediction of recovery is needed for clinical care, as well as for patient selection in clinical trials to develop the optimal treatment for different subsets of patients. This thesis focusses on the underlying mechanisms that can contribute to improvement in motor function after stroke. In the first part of this thesis, non-learning-dependent mechanisms and spontaneous neurobiological recovery after stroke were investigated. Potential clinical and neurophysiological biomarkers for sensorimotor recovery of the upper limb were monitored with repeated measurements in the first six months after stroke. Specifically the influence of somatosensory recovery on motor function was investigated, as well as several potential markers from EEG recordings. The influence of cb-tDCS on standing balance performance applied during training was investigated in chronic stroke patients. Next to that, the protocol for a randomized control trial to investigate the effect of standing balance training with cb-tDCS in sub-acute patients is described.
Jennifer Kerkman (FGB): Muscles on the Edge. A network approach for studying motor activity.
11/11/2020 | 15.45 | Aula | Main Building | VU.
Supervisor: prof. dr. A. Daffertshofer, VU. co-supervisor: dr. N. Dominici.
The redundancy in the neuromuscular system provides the opportunity to perform many functional movements but also increases the demands on the neuromuscular system to control all muscles involved in everyday whole-body movements. Presumably, muscles are controlled as (a limited set of) motor modules dependent on the task performed, reducing the degrees of freedom to that of synchronised activity in the neuromuscular system. In this thesis, electromyography was recorded and muscle synergies, information decomposition and intermuscular coherence were combined with network analysis to study the clustering of motor activity in both adults and toddlers. Functional, anatomical and neural connectivity shapes synchronised muscle activity and induces a modular control structure. This involves distinct neural pathways that complementary activate spinal motor neurons. The insights gained when studying healthy movement advocate the use of time and frequency domain analysis in combination with a network approach. This combination clearly provides the opportunity to disentangle information about the activity of multiple muscles and, by this, the control of movement.
Judith Vloothuis (Amsterdam UMC, location VUmc): Caregiver-mediated exercises after stroke.
16/11/2020: | Aula | Main Building | VU Campus | tba.
Supervisor: prof.dr. G. Kwakkel, co-supervisors: dr. E. van Wegen, dr. R. Nijland.
More time spent on exercise therapy can lead to better functional outcome in people with stroke. However, this cannot always be provided. One way to increase intensity of training could be to involve caregivers in the training of stroke patients.Therefore, in Amsterdam UMC location VUmc, together with Reade centre for rehabilitation and rheumatology, a ‘caregiver-mediated exercises’ program (CARE4STROKE) was developed. Patients and trained caregivers exercise extra hours in addition to usual therapy with this program. The (cost-) effectiveness of the CARE4STROKE program, compared to usual care, in terms of functional outcome of patients and quality of life of caregivers is studied in two rehabilitation centres and seven nursing homes. Patients and caregivers exercised a mean of 19 hours extra in addition to usual therapy, without an increase in costs. Patient and caregivers felt that exercising together was a good preparation for returning to their old home and living environment.