The role of surgery on central area metastasis remains unclear, and outcome data are still controversial. The aim of our study is to analyze the predictive value of clinical and surgical data on motor and functional outcome of patients, taking into account new emerging data on boundary irregularity of brain metastasis. We retrospectively analyzed 47 consecutive patients who underwent surgery assisted by neurophysiologic monitoring for a solitary metastasis in central area between 2010 and 2013. Inclusion criteria were as follows: good functional status (Karnofsky Performance Status (KPS) ≥70), controlled systemic disease, and absence of extra-cranial dissemination. At 1-month follow up, motor and functional outcomes were compared with preoperative clinical status, response to corticosteroids, extent of tumor resection, boundary irregularity, and size of tumor. Gross total resection was achieved in 93.6% of cases. In preoperative symptomatic patients, motor outcome (according to Medical Research Council grading scale) improved in 55.5% and worsened in 16.7%, while functional outcome (according to KPS score) improved in 50% and worsened in 14.2% of cases. No worsening occurred in preoperative asymptomatic patients. Motor outcome resulted to be not correlated with preoperative deficits, tumor volume, or preoperative response to corticosteroid treatment. Remarkably, motor outcome and extent of surgical resection appeared strongly correlated with tumor boundary irregularity (p < 0.05). Surgery with neurophysiologic monitoring on motor area metastasis can improve functional and motor condition in selected patients. Tumor volume does not represent a limit in surgery. The high correlation between clinical outcome, resection rate, and tumor boundary irregularity strengthens a new belief on the infiltrative growing pattern of brain metastasis. Motor function was evaluated according to Medical Research Council grading scale (Ott et al. 2014) while functional status was assessed according to KPS score.
Keywords: Brain metastasis; Central area; Functional outcome; Karnofsky Performance Status; Motor outcome; Neurophysiologic monitoring assisted surgery.