Left frontal low-grade glioma

Introduction

Gliomas account for 27% of all brain tumors, and the overwhelming majority of gliomas are malignant. Low-grade gliomas (LGGs) represent approximately 30% of glioma cases and include World Health Organization grade I and II tumors. The most common location for these gliomas to occur is in the frontal lobe, which many have speculated is because of the increased size of the frontal lobe as compared with other lobes and/or close proximity to neurogenic niches, such as the subventricular zone. ^, The incidence of frontal lobe involvement for LGGs ranges from 40% to 70% in several series, and at least one-half occur in the dominant hemisphere. Left-sided or dominant-hemisphere lesions are considered to carry more surgical risk as a result of close proximity to language functions and control of dominant hand functions. In this chapter, we present a left frontal LGG not adjacent to cortical language regions.

Example case

Chief complaint: seizure

History of present illness

A 40-year-old, right-handed woman with no significant past medical history who presented after a seizure event. While driving, she developed uncontrolled right arm shaking with loss of consciousness. She was seen at a local emergency room where imaging revealed a brain tumor ( Fig. 2.1 ).

Medications : Levetiracetam.
Allergies : No known drug allergies.
Past medical and surgical history : None.
Family history : No history of intracranial malignancies.
Social history : Teacher. No smoking or alcohol history.

Physical examination : Awake, alert, oriented to person, place, and time; Cranial nerves II to XII intact; No drift, moves all extremities with full strength.

	Randy L. Jensen, MD, PhD, University of Utah, Salt Lake City, UT, United States	Andreas Raabe, MD, University Hospital at Inselspital, Bern, Switzerland	George Samandouras, MD, Matthew A. Kirkman, MEd, National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom	Andrew E. Sloan, MD, University Hospital, Case Western Reserve, Cleveland, OH, United States
Preoperative
Additional tests requested	None	DTIFunctional MRINeuropsychological assessment	DTIFunctional MRIMRS and perfusion MRI	CT chest, abdomen, pelvisFunctional MRI
Surgical approach selected	Left frontal craniotomy with asleep motor mapping and intraoperative MRI confirmation	Left frontal craniotomy with asleep motor mapping	Left frontal craniotomy with awake motor and language mapping	Left fronto-parietal craniotomy with asleep motor mapping
Anatomic corridor	Left frontal	Left SFG, MFG	Left SFG, MFG	Left frontal
Goal of surgery	Diagnosis	99% resection with possible residual in left subcallosal	Maximal safe resection of both lesions	Diagnosis and maximal resection
Perioperative
Positioning	Left supine 10-degree rotation	Left supine	Supine neutral	Supine neutral
Surgical equipment	Surgical navigationIOM (MEPs)Brain stimulatorSurgical microscopeUltrasonic aspiratorIntraoeprative MRI	Surgical navigationIOM (MEPs)Brain stimulatorSurgical microscope with 5-ALAIntraoperative MRI	Surgical navigationIOM (ECoG)Brain stimulatorSurgical microscopeUltrasonic aspirator	Surgical navigationIOMBrain stimulator Surgical microscopeUltrasonic aspirator
Medications	Steroids	Antiepileptics	Steroids	MannitolSteroidsAntiepileptics
Anatomic considerations	SMA posteriorly, Broca laterally	M1, ACA, hypothalamus	Pre-SMA, SMA, motor cingulate, corpus callosum, primary motor cortex, AF	Lateral ventricle, primary motor cortex, ACA branches (pericallosal, callosomarginal)
Complications feared with approach chosen	Speech difficulty, injury to ACA vessels, SMA syndrome	Moor deficit, SMA syndrome, vascular injury	Motor deficit, language deficit, SMA syndrome	Motor deficit, ACA injury, ventricular penetration
Intraoperative
Anesthesia	General	General	Awake-awake-awake	General
Skin incision	Linear, bifrontal	Curvilinear, modified bicoronal	Semibicoronal	Modified bicoronal
Bone opening	Left anterior frontal	Left frontal encompassing both lesions	Left frontal encompassing both lesions and MFG	Left frontal encompassing both lesions
Brain exposure	Left anterior frontal	Left frontal encompassing both lesions	Left frontal encompassing both lesions and MFG	Left frontal encompassing both lesions
Method of resection	Left frontal craniotomy to encompass lesion, navigation to identify lesion, cortical motor mapping, cortisectomy over negative mapping site with tumor biopsy, microscopic dissection and tumor resection, continuous MEP, intraoperative MRI to confirm resection and supplement, update neuronavigation if further resection is needed	Craniotomy extending at least over posterior aspect of tumor and allowing anterior access, placement of grids over motor leg and arm, perform mapping, subpial resection of dorsal tumor, resect anterior tumor up to frontal superior sulcus, follow tumor to resect part of cingulate gyrus, perform subcortical mapping to identify CST, intraoperative MRI to evaluate need for further resection	Scalp block, patient remains awake, left frontal craniotomy to encompass both lesions and MFG, open dura, map primary motor cortex adjacent to posterior lesion, test language in SFG and MFG with likely negative language mapping, target anterior lesion first identifying distal ACA/genu of corpus callosum/frontal horn of lateral ventricle, subpial resection leaving pia covering falx and protecting pericallosal and callosomarginal arteries, deroof the ventricle if ependyma involved and leave EVD for 24 hours, target posterior lesion that abuts primary motor cortex, cortical motor mapping, resect lesion based on functional boundaries, debulk tumor with ultrasonic aspirator (tissue select medium and amplitude 40%), preserve all vessels including small caliber arteries and veins	Craniotomy to encompass lesion, biopsy enhancing portion of anterior lesion, place grid and map posterior lesion for primary motor cortex, resect anterior component of lesion and identify and preserve ACA branches, resect posterior lesion if anterior to primary motor cortex with continuous monopolar stimulation looking for CST, biopsy lesion if in primary motor cortex, ultrasound to help assess resection cavity
Complication avoidance	Cortical mapping, continuous MEP, focus on anterior portion of tumor, intraoperative MRI	Cortical and subcortical mapping, subpial resection, intraoperative MRI	Cortical and subcortical motor and language mapping, subpial resection, preserve all arteries and veins	Grid placement to identify functional areas, focus on anterior portion of tumor, identify and preserve ACA branches, ultrasound to assess resection cavity
Postoperative
Admission	ICU	ICU	Floor	Intermediate care
Postoperative complications feared	Speech difficulty, SMA syndrome	Motor or language deficit, SMA syndrome	Motor deficit, SMA syndrome, language deficit	Motor deficit, ventriculitis
Follow-up testing	None	MRI within 48 hours after surgeryNeuropsychological assessment 2 months after surgery	MRI within 24 hours after surgerySpeech and language assessment within 48 hours after surgery	CT immediately after surgeryMRI within 72 hours after surgery
Follow-up visits	2–4 weeks with neurooncology4–6 weeks postoperative	4 weeks after surgery	1 week after surgery with neurooncology multidisciplinary clinic	10–14 days after surgery
Adjuvant therapies recommended
Diffuse astrocytoma (IDH mutant, retain 1p19q)	STR–radiation/temozolomideGTR–radiation/temozolomide	STR–radiation/temozolomideGTR–radiation/temozolomide	STR–radiation/temozolomideGTR–observation	STR–radiation/temozolomide or PCVGTR–radiation/temozolomide or PCV
Oligodendroglioma (IDH mutant, 1p19q LOH)	STR–radiation/temozolomideGTR–observation	STR–radiation/PCVGTR–observation	STR–temozolomide +/− radiationGTR–observation	STR–radiation/temozolomideGTR–observation
Anaplastic astrocytoma (IDH wildtype)	STR–radiation/temozolomideGTR–radiation/temozolomide	STR–radiation/temozolomideGTR–radiation	STR–radiationGTR–radiation	STR–radiation/temozolomideGTR–radiation/temozolomide