Surgical Anatomy of the Forearm

The wrist is one of the most complex anatomical regions in the human body. The anatomy of the nerves in the distal forearm is very complex. The nerves are closely interrelated. Due to the embryological (segmental) development, the distribution area’s show overlap and the branches of the nerves sometimes physically touch and cross each other. This makes the wrist susceptible to neuropathic pain. These pain related complications cause severe problems in daily life of the patients. There are many hypotheses to explain the susceptibility of the wrist to neuropathic pain.
The cause of neuropathic pain until now is not clearly identified. It remains unclear at which level the actual problem is located: distal segment, Dorsal Root Ganglion or even central parts of the nervous system. It has been postulated that Nerve Growth Factor plays a role in neuropathic pain, although the exact mechanisms remain unclear. When a nerve is transected, Schwann cells, but also other cells, produce Nerve Growth Factors in the entire distal segment of this transected nerve. This production is being initiated by the axonal degeneration and the Schwann cell up-regulation, also known as Wallerian degeneration. This suggests that if two nerves overlap anatomically the increase of secretion of Nerve Growth Factor that is mediated by the injured nerve, results in binding to the high affinity Nerve Growth Factor receptor, tyrosine kinase A. This in turn leads to possible sprouting and morphological changes of uninjured fibers, that ultimately causes neuropathic pain. This pain causes severe socio-economic problems, such as partial or even full disability. Many studies have tried to find a treatment for neuropathic pain, but no definitive solution has been found. Neuropathic pain remains a hard to treat problem. Many medicinal interventions have been tried but did not have the desired effect, also surgical interventions are not always successful.
Because of the complex anatomy of the wrist, many studies have been performed to try and understand the anatomy. However, the outcome of these studies in tables and graphs is hard to extrapolate to daily practice in the operating room. The use of new dissection techniques as well as new Computer Assisted Surgical Anatomy Mapping (CASAM) can improve our understanding and make anatomy more visible for the end-user.
With the new insights in the anatomy of the forearm, as presented in this thesis and especially the new insights in the course of the various nerves in that proximity, the author tries to diminish the harmful side of an otherwise very helpful intervention. Thus, an attempt is made to prevent damage to these nerves during surgical intervention and consequently preventing neuropathic post-operative pain.