Les explorations neurophysiologiques dans les tumeurs médullaires

Predictors of functional outcome after spinal cord surgery: Relevance of intraoperative neurophysiological monitoring combined with preoperative neurophysiological and MRI assessments

OBJECTIVES

To assess the accuracy of intraoperative neurophysiological monitoring (IONM) in predicting immediate and 3-month postoperative neurological new deficit (or deterioration) in patients benefiting from spinal cord (SC) surgery; and to identify factors associated with a higher risk of postoperative clinical worsening.

METHODS

Consecutive patients who underwent SC surgery with IONM were included. Pre and postoperative clinical (modified McCormick scale), radiological (lesion-occupying area ratio), and electrophysiological features were collected.

RESULTS

A total of 99 patients were included: 14 (14.1%) underwent extradural surgery, 50 (50.5%) intradural extramedullary surgery, and 35 (35.4%) intramedullary surgery. Cumulatively, multimodal IONM (motor and somatosensory evoked potentials, D-wave whenever possible) significantly predicted postoperative deficits (p<0.001), with a sensitivity, specificity, positive predictive value, and negative predictive value of 0.81, 0.93, 0.83, and 0.92, respectively. Sixty (60.6%) patients displayed no IONM change, whereas 39 (39.4%) displayed IONM worsening. In multivariate analysis, predictors for postoperative clinical worsening were: abnormal preoperative electrophysiological assessment (p=0.03), intramedullary tumor (p<0.001), lesion-occupying area ratio ≥0.7 (p<0.001), and IONM alterations (p<0.001). Three months after the surgical procedure, in patients presenting at least one of the risk factors described above, 45/81 (55.6%) and 19/81 (23.5%) were clinically and electrophysiologically improved, respectively; while 13/81 (16.0%) and 10/81 (12.3%) were clinically and electrophysiologically worsened.

CONCLUSION

Multimodal IONM is an essential tool to guide SC surgery, and enables the accurate prediction of postoperative neurological outcome. Specific attention should be given to patients presenting with preoperative electrophysiological abnormalities, large tumor volume, and intramedullary tumor location.

Correlation of Intraoperative Neurophysiological Parameters and Outcomes in Patients with Intramedullary Tumors

Introduction

Intramedullary spinal cord tumors (IMSCT) account for about 2%-4% of all central nervous system tumors. Surgical resection is the main treatment step, but might cause damage to functional tissues. Intraoperative neuromonitoring (IONM) is an adopted measure to decrease surgical complications. Below, we describe the results of IMSCT submitted to surgery under IONM at a tertiary institution.

Methods

The sample consisted of consecutive patients with IMSCT admitted to the Neurological Institute of Curitiba from January 2007 to November 2016. A total of 47 patients were surgically treated. Twenty-three were male (48.9%) and 24 were female (51.1%). The mean age was 42.77 years. The mean follow-up time was 42.7 months.

Results

Neurological status improved in 29 patients (62%), stable in 6 (13%), and worse in 12 (25%). Patients who presented with motor symptoms at initial diagnosis had a worse outcome compared to patients with sensory impairment and pain (P = 0.026). Patients with a change in electromyography had worse neurological outcomes compared to patients who did not show changes in monitoring (P = 0.017).

Discussion and Conclusion

No prospective randomized high evidence study has been performed to date to compare clinical evolution after surgery with or without monitoring. In our sample, surgical resection was well succeeded mainly in oligosymptomatic patients with low preoperative McCormick classification and no worsening of IONM during surgery. We believe that microsurgical resection of IMSCT with simultaneous IONM is the gold standard treatment and achieved with good results.

MRI characteristics and resectability in spinal cord glioma

OBJECTIVE

The histopathology of intramedullary spinal cord tumors (IMSCT) can be suspected from the MRI features and characteristics. Ultimately, the confirmation of diagnosis requires surgery. This retrospective study addresses MRI features including homogeneity of enhancement, margination, and associated syrinx in intramedullary astrocytomas (IMA) and ependymomas (IME) that assist in diagnosis and predict resectability of these tumors.

METHODS

Single-center retrospective analysis of IMA and IME cases since 2005 extracted from the departmental registry/electronic medical records post IRB approval (IRB 201,710,760). We compared imaging findings (enhancement, margination, homogeneity, and associated syrinxes) between tumor types and examined patient outcomes.

RESULTS

There were 18 IME and 21 IMA. On preoperative MRI, IME was favored to have homogenous enhancement (OR 1.8, p = 0.0001), well-marginated (p < 0.0001, OR 0.019 [95 % CI 0.002-0.184]), and associated syrinx (p = 0.015, OR 0.192 [95 % CI 0.049-0.760]). Total excision, subtotal excision, and biopsy were performed in 12, 5, and 1 patients in the IME cohort, respectively. In the IMA group, tumors were heterogeneous and poorly marginated in 20 of the 21 patients. Total excision, subtotal excision, and biopsy were undertaken in 2, 13, and 6 patients, respectively. The success of excision was predicted by MRI, with a significant difference in the extent of resection between IME and IMA (X2 = 14.123, p = 0.001). In terms of outcome, ordinal regression analysis showed that well-margined tumors and those with homogeneous enhancement were associated with a better postoperative McCormick score. Extent of resection had statistically significant survival (p = 0.026) and recurrence-free survival (p = 0.008) benefits.

CONCLUSION

The imaging characteristics of IME and IMA have meaningful clinical significance. Homogeneity, margination, and associated syrinxes in IME can predict resectability and complexity of surgery.