Long-term functional outcomes and their relationship to nerve root sacrifice after definitive surgery for sacrococcygeal chordoma

OBJECTIVE: Wide en bloc excision of sacrococcygeal chordomas often requires sacral nerve root sacrifice because of their large size and involvement of surrounding structures. In this study, the authors characterize the long-term functional outcomes of patients following definitive resection, investigate the relationship between sacrificed nerve roots and deficits, and examine predictors of postoperative neurological deficits. METHODS: A retrospective study was conducted on all patients followed for sacral chordoma management at a quaternary spinal oncology center from 2003 to 2023. Data on patient demographics, clinical characteristics, pre- and perioperative treatment, and symptoms at last follow-up were collected. Nerve root sacrifices were documented and, where unilateral ligations were performed, the highest level of bilateral sacrifice was noted. The primary outcomes were pain, weakness, bowel or bladder dysfunction (BBD), and sensory deficits. RESULTS: Sixty-six patients were included, with a median follow-up of 5.8 (interquartile range [IQR] 3.0-8.5) years. The proportion of pain-free patients increased from 22.7% preoperatively to 54.5% after surgery, and a majority experienced improvement in pain (88.2%) and sensory deficits (83.3%). All patients who had bilateral sacrifices up to the S1-2 nerve roots and 92.9% with up to S3 bilateral nerve root sacrifice had BBD. However, motor deficits were observed in only 60.0% of those with S1 nerve root sacrifice. Additionally, 13.6% of patients had unexpected BBD and motor weakness at last follow-up. Multivariable analysis demonstrated surgical duration (odds ratio [OR] 1.003, 95% confidence interval [CI] 1.001-1.006; p = 0.020), tumor volume (OR 1.002, 95% CI 1.000-1.004; p = 0.017), and preoperative weakness (OR 37.0, 95% CI 1.3-1072.9; p = 0.036) were related to postoperative weakness. Only expected BBD due to nerve root sacrifice (OR 28.5, 95% CI 3.0-267.9; p = 0.002) was associated with postoperative BBD. Finally, preoperative sensory deficits (OR 6.6, 95% CI 1.2-36.4; p = 0.031) and surgical duration (OR 1.004, 95% CI 1.001-1.007; p = 0.003) were predictive of postoperative sensory deficits. CONCLUSIONS: En bloc excisions of sacrococcygeal chordomas require complex approaches in which surgeons must consider the long-term functional effects of nerve root sacrifice. These results provide insight into residual function following these extensive operations and suggest that preserving the S3 nerve roots is critical in minimizing BBD. Cases in which the S3 is preserved but patients continue exhibiting postoperative BBD may be related to larger tumor size and intraoperative manipulation of distal S1-3 nerves or pudendal nerves. When S1 roots are preserved, larger tumor size may predict motor weakness.