Association of postoperative navigated transcranial magnetic stimulation with accelerated motor recovery after tumor resection in the supplementary motor area.

Introduction: Following tumor resection in non-primary motor areas, patients may suffer from paresis. To distinguish between temporary and permanent deficits, our institution uses postoperative navigated transcranial magnetic stimulation (nTMS). Research question: We investigated the association of postoperative nTMS with motor recovery. Materials and methods: We retrospectively analysed the postoperative period in a cohort of 14 patients who underwent tumor resection in the supplementary motor area (SMA), suffered a postoperative paresis and underwent a single diagnostic nTMS session. The Medical Research Council Scale (MRCS) of the upper and lower limbs was added to obtain a MRCS-sum score (0-10). Patients were divided into early nTMS (<5 days after surgery) and late nTMS (≥5 days after surgery) groups, and changes in MRCS-sum scores were compared. Results: Following the nTMS session, MRCS-sum improvement was greater in the early nTMS group (2.1 ± 1.1; n = 9) than in the pre-stimulation interval in the late nTMS group (-0.3 ± 1.9; n = 5; Mann-Whitney U, p = 0.03). Improvements around the nTMS session were also larger in the early (2.1 ± 1.1) than in the late nTMS group (0.9 ± 0.9), although this difference did not reach statistical significance (p = 0.08). Linear regression identified the pre-nTMS MRCS-sum as the strongest predictor of post-nTMS improvement (p = 0.004). Discussion and conclusion: Following surgery for tumors in the SMA, our preliminary findings suggest an association between early nTMS (<5 days after surgery) and accelerated motor recovery from temporary paresis. Prospective trials are warranted.