gms | German Medical Science

Objectives: This study aimed to evaluate the safety and efficacy of the fixation of transforaminal sacral fractures using Tirobot-assisted transiliac-transsacral screws (TITSs) under multimodal neuroelectrophysiological monitoring(MNM).

Methods: From January 2019 to May 2021, 22 patients (17 males and 5 female patients) with transforaminal sacral fractures who were treated with closed reduction and placement of Tirobot-assisted TITS screw under MNM were retrospectively evaluated. The average age of the patients was 43.32±11.40 (19–63) years. Patients received MNM, including somatosensory-evoked potentials (SEP), motor-evoked potentials (MEP), and free electromyographic monitoring (EMG) prior to the beginning of surgery, and during closed reduction, placement of guide wire and TITS screw, and at the end of surgery. The operation was adjusted according to the MNM results.

Results: Overall, 22 TITS screws were inserted in 22 patients, including 5 TITS screws in the S1 body and 17 TITS in the S2 body. The average time of screw placement was 27.95±6.84 mins, and the average frequency of X-ray fluoroscopy was 31.00±5.56 times for each patient. Anterior ring fixation was performed in 4 cases using an external fixator, in five cases using cannulated screws, and in 13 cases using reconstruction plates. The mean follow-up time was 14.46±2.46 months (12–20 months). According to the Tornetta and Matta radiographic grades, 10 cases were excellent, 9 cases were good, 2 cases were fair, and 1 case was poor. The excellent and good rates were 86.36%. At the final follow-up, the Mejeed score was 82.18±14.52, 9 cases were excellent, 9 cases were good, 1 cases were fair, and 3 case was poor. The excellent and good rates were 81.81%. preoperatively, in 9 patients, the amplitude of SEP potential on the injured side was lower than that on the contralateral side before reduction (>50%). In this study, no screw was mistakenly inserted into the sacral canal, and no surgical site infection occurred.

Conclusion: MNM combined with Tirobot assistance can safely implant TITS screw, and can effectively identify the neurological function of patients under anesthesia and reduce iatrogenic nerve injury.