Floor plan - 2013 Annual Meeting - American Association for Hand ...

Brain Plasticity after Facial Reanimation Imaged by fMRI
Institution where the work was prepared: Dep of Plastic Surgery, Helsinki University Hospital, Helsinki, Finland
Tuija M. Ylä-Kotola, MD; Antti Korvenoja, MD, PhD; M Susanna C Kauhanen; Sinikka Suominen; Erkki Tukiainen; Sirpa
Asko-Seljavaara; Helsinki University Hospital
PURPOSE/INTRODUCTION
The purpose of the study was to investigate cerebral reorganization in patients treated for total facial paralysis with cross-facial nerve grafting
and microneurovascular muscle transfer. Long-lasting unilateral facial paralysis is often treated with cross-facial nerve grafting and
microneurovascular muscle transfer. To date, it is not known where in brain the cerebral activation due to the new mimic muscle function in
the transplant innervated by the contralateral facial nerve occurs. Functional Magnetic Resonance Imaging (fMRI) localizes an increased neuronal
activity in a particular area of the brain in response to voluntary tasks like muscle activity through changes in the blood oxygen.
MATERIALS/METHODS
Four consecutive female patients with unilateral facial paralysis were included in the prospective study. Three imaging sessions were
scheduled. Preoperative fMRI was done to every patient before the cross-over nerve grafting. The patients were instructed to attempt
a smile as visual cues to smile appeared at approximately 15 s intervals. During the session time series of 730 gradient-echo echo-planar
images were acquired with a Siemens Sonata 1.5 T scanner. Analysis was carried out using FEAT (FMRI Expert Analysis Tool) Version
5.43. The second session followed six to eight months after the first operation before the microneurovascular muscle transfer. Two
patients went through the second session. The third session was done approximately one year after microneurovascular muscle transfer.
Three patients have completed the study schedule so far.
RESULTS:
FMRI offers a statistical parametric map showing changes in brain activity seen during smiling. We compared the activation maps taken
before the operations, between the operations and one year after the operation. Before surgery, multiple areas of the brain were activated
by the task. After cross facial nerve grafting, activation pattern was not changed. The transferred muscle was clinically functioning
one year after facial reanimation. At this timepoint, brain activity was increased in parietal areas on both sides, and in frontal areas
on the contralateral to the original paralyzed side. Activation was also increased in anterior cingulate cortical areas in all the patients.
CONCLUSION:
We have found changes in brain activity in fMRI after facial reanimation, suggesting that brain plasticity plays a role in the adaption of
microneurovascularly transferred muscle to the face. Increased knowledge of brain plasticity offered by research combining neuroscience
and plastic surgery will benefit patients undergoing various forms of reconstruction.
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