Factors associated with progression-free survival and long-term neurological outcome after resection of intramedullary spinal cord tumors: analysis of 101 consecutive cases

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With the introduction of electrophysiological spinal cord monitoring, surgeons have been able to perform radical resection of intramedullary spinal cord tumors (IMSCTs). However, factors associated with tumor resectability, tumor recurrence, and long-term neurological outcome are poorly understood.


The authors retrospectively reviewed 101 consecutive cases of IMSCT resection in adults and children at a single institution. Neurological function and MR images were evaluated preoperatively, at discharge, 1 month after surgery, and every 6 months thereafter. Factors associated with gross-total resection (GTR), progression-free survival (PFS), and long-term neurological improvement were assessed using multivariate regression analysis.


The mean age of the patients was 41 ± 18 years and 17 (17%) of the patients were pediatric. Pathological type included ependymoma in 51 cases, hemangioblastoma in 15, pilocytic astrocytoma in 16, WHO Grade II astrocytoma in 10, and malignant astrocytoma in 9. A GTR was achieved in 60 cases (59%). Independent of histological tumor type, an intraoperatively identifiable tumor plane (OR 25.3, p < 0.0001) and decreasing tumor size (OR 1.2, p = 0.05) were associated with GTR. Thirty-four patients (34%) experienced acute neurological decline after surgery (associated with increasing age [OR 1.04, p = 0.02] and with intraoperative change in motor evoked potentials [OR 7.4, p = 0.003]); in 14 (41%) of these patients the change returned to preoperative baseline within 1 month. In 31 patients (31%) tumor progression developed by last follow-up (mean 19 months). Tumor histology (p < 0.0001) and the presence of an intraoperatively identified tumor plane (hazard ratio [HR] 0.44, p = 0.027) correlated with improved PFS. A GTR resulted in improved PFS for hemangioblastoma (HR 0.004, p = 0.04) and ependymoma (HR 0.2, p = 0.02), but not astrocytoma. Fifty-five patients (55%) maintained overall neurological improvement by last follow-up. The presence of an identifiable tumor plane (HR 3.1, p = 0.0004) and improvement in neurological symptoms before discharge (HR 2.3, p = 0.004) were associated with overall neurological improvement by last follow-up (mean 19 months).


Gross-total resection can be safely achieved in the vast majority of IMSCTs when an intraoperative plane is identified, independent of pathological type. The incidence of acute perioperative neurological decline increases with patient age but will improve to baseline in nearly half of patients within 1 month. Long-term improvement in motor, sensory, and bladder dysfunction may be achieved in a slight majority of patients and occurs more frequently in patients in whom a surgical plane can be identified. A GTR should be attempted for ependymoma and hemangioblastoma, but it may not affect PFS for astrocytoma. For all tumors, the intraoperative finding of a clear tumor plane of resection carries positive prognostic significance across all pathological types.

Abbreviations used in this paper: GTR = gross-total resection; HR = hazard ratio; IMSCT = intramedullary spinal cord tumor; IQR = interquartile range; MEP = motor evoked potential; MMS = Modified McCormick Scale; PFS = progression-free survival; STR = subtotal resection.

Article Information

Address correspondence to: Matthew J. McGirt, M.D., 600 North Wolfe Street, Meyer 8-161, Baltimore, Maryland 21287. email:mmcgirt1@jhmi.edu.

© AANS, except where prohibited by US copyright law.



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    Intraoperative photograph of a clear intraoperative plane for IMSCT resection, showing the identifiable transition between tumor and healthy spinal cord. Hemangioblastoma, ependymoma, and pilocytic astrocytoma were more likely to have a clearly identifiable plane of resection than WHO Grade II astrocytomas and malignant astrocytomas (p = 0.007). Independent of histology, the presence of an intraoperative plane of tumor resection was associated with greater likelihood of GTR (p < 0.001), increased PFS (p = 0.005), and increased likelihood of longterm overall neurological improvement (p = 0.0002).

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    Sagittal T1-weighted Gd-enhanced MR images of an intramedullary ependymoma obtained preoperatively (A) and 48 hours after GTR (B).

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    Sagittal T1-weighted Gd-enhanced MR images of an intramedullary ependymoma obtained preoperatively (A) and 48 hours after GTR (B).

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    Sagittal T1-weighted Gd-enhanced MR images of an intramedullary high-grade astrocytoma obtained before surgery (A) and 48 hours after STR (B).

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    Kaplan-Meier plot demonstrating PFS rates in 101 cases in which an IMSCT was resected, stratified by tumor pathology. In 31 patients (31%) disease progression was noted at a median of 11 months postoperatively. Progression-free survival was correlated with tumor pathology (p < 0.0001). The median time to progression was 6.5 months for malignant astrocytoma and 20 months for low-grade astrocytoma. The 5-year PFS rates for hemangioblastoma and ependymoma were 82 and 63%, respectively.

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    Kaplan-Meier plot demonstrating PFS rates after resection of intramedullary ependymoma (A) and intramedullary hemangioblastoma (B), stratified by the extent of resection. Gross-total resection (defined as a lack of residual tumor enhancement on 48-hour postoperative MR imaging) was obtained in 60 patients (59%). It was associated with improved PFS in patients with ependymoma and hemangioblastoma (p = 0.02 and p = 0.004, respectively). In no case did a hemangioblastoma recur at 5 years after GTR.

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    Line graph depicting the incidence of motor, sensory, and bladder function improvement as a function of time after resection. By 18 months postoperatively, 46% of patients with preoperative dysesthetic symptoms had improvement in these symptoms (to minimal or none), 53% with preoperative motor weakness had improved ability (to full strength), and 53% with preoperative bladder dysfunction had improved function (to being continent of urine). These symptoms improved at similar rates.

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    Kaplan-Meier plots demonstrating PFS (A) and incidence of overall neurological improvement over time (B) after resection, based on the presence or absence of a clear intraoperative resection plane. The presence of a tumor plane was associated with improved PFS (p = 0.027) and long-term neurological improvement (p = 0.0002), independent of tumor histology.



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