Neurospine.  2022 Mar;19(1):32-40. 10.14245/ns.2142698.349.

Remnant Tumor Margin as Predictive Factor for Its Growth After Incomplete Resection of Cervical Dumbbell-Shaped Schwannomas

• Kitamura K
• Nagoshi N
• Tsuji O
• Suzuki S
• Nori S
• Okada E
• Yagi M
• Matsumoto M
• Nakamura M
• Watanabe K

• KMID: 2528373
• DOI: http://doi.org/10.14245/ns.2142698.349

Abstract

Objective
The purpose of our study was to investigate the risk factors of remnant tumor growth after incomplete resection (IR) of cervical dumbbell-shaped schwannomas (DS).
Methods
Twenty-one patients with IR of cervical DS with at least 2 years of follow-up were included and were divided into 2 groups: the remnant tumor growth (G) (n = 10) and no growth (NG) (n = 11) groups. The tumor location in the axial plane according to Toyama classification, the location of the remnant tumor margin, and the tumor growth rate (MIB-1 index) index were compared.
Results
No significant differences in Toyama classification and MIB-1 index were found. Age was significantly higher in the G group (61.4 years vs. 47.6 years; p = 0.030), but univariate logistic regression analysis revealed little correlation to the growth (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.001–1.166; p = 0.047). Seventeen patients (9 in the G and 8 in the NG group) underwent the posterior one-way approach, and significant differences in the location of the remnant tumor margin were confirmed: within the spinal canal in 1 and 0 case, at the entrance of the intervertebral foramen in 7 and 1 cases, and in the foramen distal from the entrance in 1 and 7 cases, in the G and NG groups, respectively (p = 0.007). The proximal margin was identified as a significant predictor of the growth (OR, 56.0; 95% CI, 2.93–1,072; p = 0.008).
Conclusion
Remnant tumors with margins distally away from the entrance of the foramen were less likely to grow after IR of cervical DS.

Keyword

Cervical spinal cord tumor; Dumbbell; Schwannoma; Residual tumor; Surgical margin; MIB-1