Supplementary Motor Area Syndrome in Neurosurgical Practice

Abstract

Supplementary motor area (SMA) syndrome is a distinct
clinical entity observed following surgery of the medial
frontal cortex particularly in procedures targetting intraaxial
lesions and epileptogenic zones. Characterized by
transient, contralateral hemiparesis and, with dominant
hemisphere involvement and speech initiation deficits,
SMA syndrome presents a significant but reversible
postoperative challenge. With the integration of advanced
neuroimaging and intraoperative neural tract mapping
techniques, our understanding of neuroplasticity in the
clinical trajectory and recovery following SMA syndrome
has substantially progressed. This review aims to synthesize
recent, high-impact studies in the context of brain tumour
and epilepsy surgery outlining contemporary insights into
SMA function, surgical planning and recovery mechanisms.
We contextualize these developments in the light of the
foundational work of Laplane et al. (1977), who first
characterized the syndrome and explore novel findings on
the role of the frontal aslant tract (FAT) in SMA connectivity.
The aim is to provide neurosurgeons and neuroscientists
with an evidence-based understanding of SMA syndrome
and highlight implications for improving functional
outcomes in neuro-oncological and epilepsy surgery.