Neurophysiologic cut off values for safe resection of patients with supratentorial gliomas

BACKGROUND

Gliomas have infiltrative nature and tumor volume has direct prognostic value. Optimal resection limits delineated by high-frequency monopolar stimulation with multipulse short train technique is still a matter of debate for safe surgery without (or with acceptable) neurological deficits. It is also an enigma whether the same cut-off values are valid for high and low grades. We aimed to analyze the value of motor mapping/monitoring findings on postoperative motor outcome in diffuse glioma surgery.

METHODS

Patients who were operated on due to glioma with intraoperative neuromonitorization at our institution between 2017 and 2021 were analyzed. Demographic information, pre- and post-operative neurological deficit, magnetic resonance images, resection rates, and motor evoked potential (MEP) findings were analyzed.

RESULTS

Eighty-seven patients of whom 55 had high-grade tumors were included in the study. Total/near-total resection was achieved in 85%. Subcortical motor threshold (ScMTh) from resection cavity to the corticospinal tract was ≤ 2mA in 17; 3 mA in 14; 4 mA in 6; 5 mA in 7, and ≥5mA in 50 patients. On the 6th month examination, six patients (5 with high-grade tumor) had motor deficits. These patients had changes in MEP that exceeded critical threshold during monitoring. Receiver operating characteristic analysis revealed 2.5 mA ScMTh as the cut-off point for limb paresis after awakening and 6 months for the groups.

CONCLUSIONS

Subcortical mapping with MEP monitoring helps to achieve safe wider resection. The optimal safe limit for SCMTh was determined as 2.5 mA. Provided that safe threshold values are maintained in MEP, surgeon may force the functional limits by lowering the SCMTh to 1 mA, especially in low-grade gliomas.

Serum hyaluronidase levels in patients with aneurysmal subarachnoid haemorrhage

INTRODUCTION

The purpose of this study was to investigate the time course(s) of the serum hyaluronidase levels in patients with aneurysmal subarachnoid haemorrhage and to show whether there is a correlation between symptomatic vasospasm and serum levels of hyaluronidase.

METHODS

This prospective, open, non-randomised clinical study consisted of 20 patients with aneurysmal subarachnoid haemorrhage, and eight patients with normotensive hydrocephalus who served as the control group. Serum hyaluronidase levels were detected within the first three days, days five and seven after aneurysmal subarachnoid haemorrhage, and the results were compared with those from the control group. The results were also compared with those of the clinical parameters, including the patient's outcome at six months and symptomatic vasospasm.

RESULTS

Mean serum hyaluronidase levels were higher on days five and seven, and comparisons with either day five (p-value is 0.001) and/or day seven (p-value is 0.00001) showed a statistical difference between subarachnoid haemorrhage and controls. However, no relationship was found between elevated serum hyaluronidase levels and the clinical parameters including symptomatic vasospasm (p-value is greater than 0.05) and outcome at sixth months (p-value is greater than 0.05).

CONCLUSION

Our results indicate that serum hyaluronidase is elevated in the acute stage(s) of subarachnoid haemorrhage; however, no difference was found between serum hyaluronidase levels and subarachnoid haemorrhage severity. Clinical studies with larger population of patients with aneurysmal subarachnoid haemorrhage are required.

Intradural migration of a bullet following spinal gunshot injury

STUDY DESIGN

Case report.

OBJECTIVES

To report a penetrating gunshot injury at L1 with migration within the spinal canal to S2.

SETTING

Istanbul, Turkey.

METHODS

A 44-year-old man was admitted with an entrance gunshot wound on the left upper quadrant. An emergency exploratory laparotomy with left nephrectomy and transverse colon repair were performed. He had complete spinal cord injury below the level of L1. Lumbar magnetic resonance imaging (MRI) revealed hemorrhagic areas in conus medullaris and L1 corpus. The bullet was lodged at the S2 level. S1-S2 laminectomies were performed for the removal of the bullet. The antibiotic therapy was given for 17 days.

RESULTS

No meningitis or wound infection was observed after the operation. At discharge his neurological status was improved.

CONCLUSIONS

The present case presented the movement of an intraspinal bullet after a spinal gunshot injury. No signs of infection were detected postoperatively. Lumbar MRI was used safely without any change in neurological status or patient discomfort.