|Paper title||Postoperative transcranial magnetic stimulation to predict motor recovery after eloquent tumor surgery|
|Form of presentation||Poster|
Goals: Removing the last and deepest part of tumor near eloquent areas potentially puts neurological functions at risk. To know whether postoperative deficits are transient or permanent is important not only for the patient but also for the neurosurgeon, the physiotherapist and the oncologist. The objective of the present study was to analyze the value of postoperative navigated TMS to predict recovery of motor function.
Methods: We retrospectively identified patients who underwent postoperative TMS mapping within 14 days after surgery for a supratentorial tumor or AVM between September 2014 and December 2017. Patients were included in this study if they had a motor deficit of Medical Research Council Grade (MCRS) 0 to 4-, regardless of pre-surgical motor function. Each paretic limb was evaluated separately.
Results: nTMS mapping was performed on average 5.4 days after surgery. A positive MEP by nTMS could be elicited in 11 of 15 paretic limbs. Univariate GEE analysis yielded a significant prediction of postoperative recovery by a positive MEP response on nTMS with an odds ratio of 11.7 (95% confidence interval 1.04 – 132, p=0.046). Of the 11 limbs with a positive MEP on nTMS, 10 showed a good functional recovery at 1 month, yielding a sensitivity of 90.9%. Of the 4 limbs with a negative MEP on nTMS, only 3 showed a poor functional recovery at 1 month, yielding a specificity of 75%.
Therefore we could demonstrate the following: If early postoperative TMS within 14 days after surgery elicited a MEP response, the patient did recover for this extremity within 1 month at least to M4 in MRCS. In case no MEP response could be elicited with 70-100% of maximal TMS machine output, 75% of these extremities did not recover significantly.
Conclusions: Early postoperative navigated TMS reliably predicts long term motor recovery of patients suffering from severe motor deficits directly after motor eloquent tumor resection.