Motor Outcomes After Surgical Resection of Lesions Involving the Motor Pathway: A Prognostic Evaluation Scale.

BACKGROUND: Preservation of function is essential in surgical resection of lesions involving the motor pathways. The aim of this work is to evaluate the effect of anatomic features of lesions located in the motor pathway on neurologic and functional outcome. We propose an evaluation score to assess the risk of postoperative worsening.

METHODS: A total of 92 patients suffering from lesions involving the motor pathways have been studied for what concerns motor functions (muscular strength scale [MRC]) after surgical treatment. Patient-related, surgery-related, and lesion-related data were recorded to identify relations with motor outcomes. Cortical surfacing of the lesion and amount of millimeters of interface between the lesion and corticospinal tract have been investigated with preoperative magnetic resonance imaging sequences and tractographic reconstructions.

RESULTS: Means of the MRC Scale preoperative and 7 days postoperative were 3.6 ± 2.23 and 3.8 ± 2.28 for the upper limbs, and 4.1 ± 2.31 and 4.4 ± 2.33 for the lower limbs, respectively. Patients that were stable or improved at 7 days from surgery were 82.6%. The anatomic features investigated have been summed up in a single score (envelopment/surfacing [ES]). In cases of ES classes V and VI, a total cumulative predicted worsening rate was 24.2% and 14.8%, respectively. The risk of worsening was 1.682 times greater for the higher ES classes (IV-VI).

CONCLUSIONS: The anatomic features of lesions are crucial in the prediction of motor outcome. The new proposed score (ES score) is useful to stratify motor function prognosis.