Motor Function of the Upper-Extremity after Transection of the Second Thoracic Nerve Root during Total En Bloc Spondylectomy

BACKGROUND In total en bloc spondylectomy (TES) of upper thoracic spine including the second thoracic (T2) vertebra, T2 nerve roots are usually transected. In this study, we examined the association between transection of the T2 nerve roots and upper-extremity motor function in patients with upper thoracic TES. METHODS We assessed 16 patients who underwent upper thoracic TES with bilateral transection of the T2 nerve roots. Patients were divided into three groups: 3 patients without any processing of T1 and upper nerve roots (T2 group), 7 with extensive dissection of T1 nerve roots (T1-2 group), and 6 with extensive dissection of T1 and upper nerve roots (C-T2 group). Postoperative upper-extremity motor function was compared between the groups. RESULTS Postoperative deterioration of upper-extremity motor function was observed in 9 of the 16 patients (56.3%). Three of the 7 patients in the T1-2 group and all 6 patients in the C-T2 group showed deterioration of upper-extremity motor function, but there was no deterioration in the T2 group. In the T1-2 group, 3 patients showed mild deterioration that did not affect their activities of daily living and they achieved complete recovery at the latest follow-up examination. In contrast, severe dysfunction occurred frequently in the C-T2 group, without recovery at the latest follow-up. CONCLUSIONS The transection of the T2 nerve roots alone did not result in upper-extremity motor dysfunction; rather, the dysfunction is caused by the extensive dissection of the T1 and upper nerve roots. Therefore, transection of the T2 nerve roots in upper thoracic TES seems to be an acceptable procedure with satisfactory outcomes.