Higher intraoperative blood loss is associated with increased risk of intraoperative neuromonitoring data loss for the type 3 spinal cord shape during spinal deformity surgery.

PURPOSE

To assess risk factors associated with an increased risk of intraoperative neuromonitoring (IONM) loss among spinal deformity patients with type 3 spinal cord (T3SC) shapes.

METHODS

This is a retrospective cohort study of adult and pediatric patients with T3SC undergoing spinal deformity surgery from a single center between 2016 and 2023. The primary outcome examined was whether there was IONM data loss. Demographic, clinical, operative, and radiographic variables were compared between patients with and without IONM data loss.

RESULTS

A total of 79 patients with T3SC were identified: 31 (39.2%) had IONM data loss, while 48 (60.8%) did not. There were no differences between the groups in terms of age, sex, or BMI (p > 0.05). There were no significant differences in the preoperative and postoperative coronal (C-DAR), sagittal (S-DAR), or total deformity angle ratio (T-DAR) (p > 0.05). There was no difference in the proportion of patients with a VCR, or in the mean instrumented number of levels. There was no difference in measured cord deformation using the area of the spinal cord shape as well as the long- and short-axis dimensions on an axial MRI cut. However, there was a statistically significantly higher EBL (1320.7 ± 614.0 vs. 1049.0 ± 468.4, p = 0.0316), TXA use (2619.8 ± 1333.1 cc vs. 1925.9 ± 1304.2, p = 0.0372), and cell saver salvage (468.5 ± 266.2 vs. 311.5 ± 266.2, p = 0.0264) in the IONM-Loss group.

CONCLUSION

In this largest reported cohort patients with T3SC undergoing spinal deformity surgery, the only factors found to be significantly associated with an increased risk of IONM loss was higher EBL, higher autologous salvage transfused blood volume, and higher TXA given. It is critical for deformity surgeons to be aware of the importance of blood and hemodynamics management when treating this unique and high-risk population.