Abstract
The ability to visualize the brain's fiber connections noninvasively in vivo is relatively
young compared with other possibilities of functional magnetic resonance imaging.
Although many studies showed tractography to be of promising value for neurosurgical
care, the implications remain inconclusive. An overview of current applications is
presented in this systematic review. A search was conducted for ((“tractography” or
“fiber tracking” or “fibre tracking”) and “neurosurgery”) that produced 751 results.
We identified 260 relevant articles and added 20 more from other sources. Most publications
concerned surgical planning for resection of tumors (n = 193) and vascular lesions (n = 15). Preoperative use of transcranial magnetic stimulation was discussed in 22
of these articles. Tractography in skull base surgery presents a special challenge
(n = 29). Fewer publications evaluated traumatic brain injury (TBI) (n = 25) and spontaneous intracranial bleeding (n = 22). Twenty-three articles focused on tractography in pediatric neurosurgery. Most
authors found tractography to be a valuable addition in neurosurgical care. The accuracy
of the technique has increased over time. There are articles suggesting that tractography
improves patient outcome after tumor resection. However, no reliable biomarkers have
yet been described. The better rehabilitation potential after TBI and spontaneous
intracranial bleeding compared with brain tumors offers an insight into the process
of neurorehabilitation. Tractography and diffusion measurements in some studies showed
a correlation with patient outcome that might help uncover the neuroanatomical principles
of rehabilitation itself. Alternative corticofugal and cortico-cortical networks have
been implicated in motor recovery after ischemic stroke, suggesting more complex mechanisms
in neurorehabilitation that go beyond current models. Hence tractography may potentially
be able to predict clinical deficits and rehabilitation potential, as well as finding
possible explanations for neurologic disorders in retrospect. However, large variations
of the results indicate a lack of data to establish robust diagnostical concepts at
this point. Therefore, in vivo tractography should still be interpreted with caution
and by experienced surgeons.
Keywords
neurosurgery - tractography - neuronavigation - neurorehabilitation - fiber tracking
