Supplementary Motor Area Syndrome after Removal of an Unusual Extensive Parasagittal Meningioma: Analysis of Twelve Reported Cases

Background and Objectives: Supplementary motor area (SMA) syndrome is a common post-operation complication in intra-axial brain tumors, such as glioma. Direct damage to parenchyma or scarification of the major vessels during an operation are the main causes. However, it is rarely reported as a postoperative complication in extra-axial tumors. Materials and Methods: We reviewed 11 reported cases of supplementary motor area syndrome after removal of extra-axial meningiomas in the English literature from the PubMed database. We also added our case, which presented as an unusual huge meningioma, to analyze the clinical parameters and outcomes of these 12 reported cases. Results: Recovery time of supplementary motor area syndrome in extra-axial tumors could be within 1–7 weeks, shorter than intra-axial tumors (2–9 weeks). Epilepsy and progressive limb weakness are the most common presentations in 50% of cases. Different degrees of postoperative muscle power deterioration were noted in the first 48 h (from 0–4). Lower limbs (66.6%, 8/12) were slightly predominant compared to upper limbs (58.3%, 7/12). Mutism aphasia was also observed in 41.6% (5/12, including our case), and occurred in tumors which were involved in the dominant side; this recovered faster than limb weakness. Discussion and Conclusions: Our work indicated that SMA syndrome could occur in extra-axial brain tumors presenting as mutism aphasia and limb weakness without any direct brain parenchyma damage. In our analysis, we found that recovery time of postoperative motor function deficit could be within 1–7 weeks. Our study also provides a further insight of SMA syndrome in extra-axial brain tumors.