Table S1.Intraoperative electrophysiological events during the main surgicalphases in 25 patients with intramedullary spinal cord tumors

No. / Histopathology,tumor location / Main surgical phases / Electrophysiological status at end of surgery / Postoperative motor status / Classification
Opening of spinal cord to before tumor removal / During tumor removal (in chronological order) / 24 h after surgery / 1 month follow-up / 24 h after surgery(>50% / all-or-none) / 1 month follow-up(>50% / all-or-none)
1 / Cavernous angioma, T2 / fEMG Lt legs tonic / MEP both legs decrease, SEP both legs decrease, fEMG both legs tonic / SEP recovery, MEP no recovery (> 50%), MEP recovery (all-or-none) / ─ / ─ / FP/ TN / FP / TN
2 / Hemangioma, C4 / None / fEMG Lt leg tonic, MEP Lt U/E decrease / MEP Lt U/E no recovery (> 50%), MEP recovery (all-or-none) / +(Lt arm weakness) / ─ / TP / FN / FP / TN
3 / Ependymoma, C1-5 / None / fEMG both U/E tonic*+, MEP both U/E decrease / MEP Lt U/E no recovery (> 50%), MEP recovery (all-or-none) / ─ / ─ / FP/ TN / FP / TN
4 / Astrocytoma, C1-3 / None (SEP Lt side unmonitorable) / MEG both trapezius, deltoid and biceps decrease, FEMG both trapezius tonic / MEP no recovery (> 50%), MEP recovery (all-or-none) / ─ / ─ / FP/ TN / FP / TN
5 / Hemangioblastom,C2 / None / None / None / ─ / ─ / TN / TN / TN / TN
6 / Ependymoma,C2-6 / fEMG Rt biceps, SEP both U/E and Lt L/E decrease, MEP Lt thenar decrease / SEP Lt U/E decrease, fEMG Lt U/E tonic*+, MEP Lt TA and thenar loss, fEMG Lt U/E tonic / SEP Lt side no recovery,
MEP Lt thenar and Rt TA no recovery (both > 50% and all-or-none) / + (Lt U/E weakness) / ─ / TP / TP / TP / TP
7 / Hemangioblastoma, T9-10 / None / None / None / ─ / ─ / TN / TN / TN / TN
8 / Subependymoma, T10-11 / None / fEMG both legs tonic*+, MEP Lt leg decrease / MEP recovery / ─ / ─ / TN / TN / TN / TN
9 / Ependymoma, T7-8 / None / fEMG Rt L/E tonic*+, MEP Lt TA and AH loss, MEP Rt AH decrease, fEMGboth L/E tonic / MEP Lt TA no recovery (both > 50% and all-or-none) / ─ / ─ / FP / FP / FP / FP
10 / Ependymoma, C4-5 / None / fEMG Rt thenar tonic*+, MEP both U/E and L/E decrease, SEP both U/E decrease / SEP recovery
MEP recovery / ─ / ─ / TN / TN / TN / TN
11 / Epidermal cyst with dystrophic calcification, L2-3 / None / None / None / ─ / ─ / TN / TN / TN / TN
12 / Ependymoma, C6-7 / SEP Rt L/E loss / fEMG Rt thenar tonic*+ / SEP no recovery
MEP Rt thenar decrease (> 50%), no MEP event (all-or-none) / + (Rt hand weakness) / ─ / TP / FN / FP / TN
13 / Ependymoma, C3-5 / SEP Lt L/E decrease (SEP Rt L/E unmonitorable) / fEMG Rt U/E tonic*+, SEP Lt L/E loss, MEP both U/E decrease / SEP no recovery
MEP recovery / ─ / ─ / TN / TN / TN / TN
14 / Hemangioma, T4-5 / fEMG Lt L/E tonic / fEMG both L/E tonic*+, SEP Lt L/E loss, MEP both TA loss / SEP recovery
MEP recovery / ─ / ─ / TN / TN / TN / TN
15 / Hemangioma,C3-4 / SEP Rt L/E and Lt U/E decrease / fEMG both thenar tonic, SEP Rt L/E decrease and Lt U/E loss, fEMG both U/E tonic / SEP no recovery / + (both U/E weakness) / + (both U/E weakness) / TP / TP (based on fEMG event) / TP / TP (based on fEMG event)
16 / Astrocytoma,
C4-5 / None / None / None / ─ / ─ / TN / TN / TN / TN
17 / Hemangioma,C3-4 / None / fEMG Rt deltoid tonic*+, SEP Rt U/E decrease, MEP both U/E decrease / SEP Rt U/E no recovery
MEP recovery / ─ / ─ / TN / TN / TN / TN
18 / Ependymoma, T3-4 / SEP both L/E decrease / fEMG Lt L/E tonic*+, SEP both L/E decrease, MEP both L/E decrease and loss / SEP no recovery,
MEP no recovery (both > 50% and all-or-none) / ─ / + (ambulation difficulty) / FP / FP / TP / TP
19 / Ependymoma,T12-L1 / None (SEP both L/E unmonitorable) / fEMG both L/E tonic / None / ─ / ─ / TN / TN / TN / TN
20 / Astrocytoma,
T12-L1 / None / fEMG Rt AH tonic*+, MEP Rt AH decrease / MEP recovery / ─ / ─ / TN / TN / TN / TN
21 / Ependymoma, C3-5 / None (SEP Lt side and Rt L/E unmonitorable) / fEMG Rt U/E tonic*+, SEP Rt U/E loss, MEP Lt TA, Rt AH, and thenar decrease, fEMG U/E tonic, MEP Lt TA loss / SEP recovery,
MEP recovery except Lt. TA(both > 50% and al-or-none) / ─ / ─ / FP / FP / FP / FP
22 / Ependymoma,C5 / SEP both L/E decrease, fEMG Rt L/E phasic / fEMG both thenar tonic*+, MEP both thenar decrease and Rt TA loss / SEP no recovery,
MEP Rt TA and AH no recovery (> 50% ), MEP recovery (all-or-none) / ─ / ─ / FP / TN / FP / TN
23 / Subependymoma,T10-11 / None / MEP Lt L/E loss, SEP Rt L/E decrease / SEP recovery,
MEP recovery (both > 50% and all-or-none) / ─ / ─ / TN / TN / TN / TN
24 / Ependymoma, C2 / SEP both U/E decrease(SEP both L/E unmonitorable) / SEP both U/E loss, MEP both U/E and L/E decrease and loss / SEP no recovery,
MEP both triceps no recovery(> 50% ), MEP recovery (all-or-none) / ─ / ─ / FP / TN / FP / TN
25 / Carvernos angioma, C4 / fEMG Rt thenar tonic / MEP both U/E and L/E decrease / MEP no recovery(> 50% ), MEP recovery (all-or-none) / ─ / ─ / FP / TN / FP / TN

*+An fEMG event indicative of an upcomingmMEP event;AH = abductor hallucis; FN = false negative; FP = false positive; L/E = lower extremity; TA = tibialis anterior; TN = true negative; TP = true positive; U/E = upper extremity; Lt = left; Rt = right

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