Neurological outcomes following nerve root sacrifice during resection of dumbbell tumors of the spine: a systematic review and pooled analysis

In the surgical treatment of spinal dumbbell tumors, preservation of the nerve root of origin is often challenging, and complete tumor removal may require intentional sacrifice of motor-relevant nerve roots. Despite this, postoperative motor deficits are frequently minimal or transient, as reported by several series. This systematic review and meta-analysis evaluates neurological outcomes following nerve root sacrifice at motor-relevant levels. A systematic search of PubMed, Scopus and Web of Science was performed per PRISMA guidelines. Studies included adult patients (≥ 18 years) with dumbbell tumors at motor-relevant spinal levels (C5–T1, L3–S1) treated with nerve root sacrifice. Pooled analyses and meta-analyses of proportions were conducted, including subgroup analyses for lumbar and cervical tumors. Twelve studies comprising 121 patients were included. After pooling of raw data across studies, crude rates of immediate and persistent motor deficits were 46% and 18%, respectively. Meta-analytic estimates showed immediate deficits in 46% (95% CI: 31%–62%) and persistent deficits in 21% (95% CI: 14%–31%). Severe persistent motor deficits (Medical Research Council grade ≤ 3) were rare, occurring in 1% (95% CI: 0%–7%); crude rate was 4%. Sensory deficits were more variable across studies. Most patients tolerate nerve root sacrifice without significant long-term motor impairment, likely due to chronic nerve compression inside the intervertebral foramen and neural compensation. Although transient motor deficits are frequent, severe permanent deficits are uncommon. Our analysis provides the first synthesis of the literature on this topic to help supporting surgical decision making. Caution in interpretating these results is still warranted due to small sample sizes and potential publication bias.