Is open (craniotomy‑based) resection feasible for a 25‑year‑old woman with a 5 × 4 × 3 cm glioma in the left basal ganglia causing thalamic compression and extending toward the midline and ventricle?

Open Craniotomy for Deep Basal Ganglia Glioma: Feasibility and Approach

Open surgical resection via craniotomy is technically feasible for this 5 × 4 × 3 cm basal ganglia glioma, but the decision must weigh the achievable extent of resection against the substantial risk of permanent neurological deficits given the deep location involving eloquent structures (thalamus, basal ganglia, proximity to internal capsule and corticospinal tract). 1, 2

Primary Surgical Considerations

Resectability Assessment

• Deep-seated gliomas in the basal ganglia and thalamus are surgically accessible but require meticulous microsurgical technique and contemporary intraoperative adjuncts to minimize morbidity 1, 2
• The tumor size (5 cm maximal diameter) falls within the range where maximal safe resection (MSR) has been successfully achieved in specialized centers, with one series reporting 95% combined subtotal/gross-total resection rates for thalamic gliomas 2
• Location in eloquent structures (basal ganglia, thalamic compression) significantly increases surgical risk compared to superficial or non-eloquent lesions 1

Critical Technical Requirements

The EANO guidelines emphasize that preventing new permanent neurological deficits that compromise independence and quality of life is more important than extent of resection, because diffuse gliomas are not cured by surgery 1

Essential intraoperative tools for safe resection include: 1, 2

• Surgical navigation systems with functional MRI and diffusion tensor imaging datasets
• Intraoperative MRI or ultrasonography for real-time assessment
• Evoked potentials and electromyography monitoring
• Motor and sensory pathway mapping (awake craniotomy may be considered if language areas are at risk)
• Fluorescence-guided visualization with 5-aminolevulinic acid

Risk-Benefit Analysis by Patient Age and Tumor Grade

If Low-Grade Glioma (WHO Grade I-II)

• Maximal safe resection is the treatment of choice and can significantly improve outcomes, particularly in younger patients 2, 3
• The 2-year overall survival for low-grade thalamic gliomas after MSR reaches 90% 2
• Gross total resection (>90% removal) in low-grade gliomas yields 5- and 10-year survival rates of 97% and 91% respectively 4
• For a 25-year-old patient, aggressive surgical approach is more justified given the decades of potential life-years gained 2

If High-Grade Glioma (WHO Grade III-IV)

• Surgical resection remains beneficial even for deep-seated high-grade gliomas, with extent of resection being an independent prognostic factor 2, 5
• However, the 2-year survival for high-grade thalamic gliomas is only 15% even with MSR 2
• Temporary postoperative motor deficits occur in approximately 29% of deep glioma resections, though most improve during early postoperative period 2
• Permanent neurological morbidity rates for deep basal ganglia/thalamic lesions range from 5-18% with mortality approaching 2% 1

Alternative to Open Craniotomy: Stereotactic Biopsy

Stereotactic needle biopsy should be strongly considered as the initial approach if: 6

• The primary goal is histologic diagnosis and molecular profiling to guide adjuvant therapy
• Immediate relief of mass effect is not required (patient is neurologically stable)
• The lesion involves deep eloquent structures where resection risk is prohibitive

Advantages of Stereotactic Approach

• Avoids craniotomy with shorter anesthesia time and lower procedural risk 6
• Enables safe targeting of deep basal ganglia and thalamic regions 6
• Provides adequate tissue for molecular markers (IDH mutation, 1p/19q codeletion, MGMT promoter methylation) which are homogeneously distributed 1

When Craniotomy is Mandatory

Open resection via craniotomy is indicated when: 6, 7

• Patient has symptomatic mass effect requiring immediate decompression (progressive motor weakness, altered consciousness, impending herniation)
• Tumor debulking is expected to provide therapeutic benefit beyond diagnosis
• Steroid-dependent symptoms cannot be controlled medically

Surgical Approach Selection for This Case

Given the left basal ganglia location with thalamic compression and ventricular extension, potential surgical corridors include: 2

• Transtemporal approach (29% of thalamic gliomas in one series) - accesses lateral thalamus and basal ganglia
• Anterior interhemispheric transcallosal approach (29%) - for medial extension toward ventricle
• Superior parietal lobule approach (25%) - for posterolateral access

Staged resections should be considered for complex deep gliomas to minimize single-operation morbidity while achieving maximal safe cytoreduction 2

Critical Pitfalls to Avoid

• Do not assume craniotomy is mandatory - stereotactic biopsy safely achieves diagnosis in most deep-seated lesions without the morbidity of open surgery 6
• Do not prioritize extent of resection over functional preservation - new permanent deficits that compromise independence are worse outcomes than subtotal resection 1
• Do not proceed without molecular diagnosis - histologic grade and molecular markers (particularly IDH status) fundamentally alter prognosis and treatment strategy, justifying biopsy-first approach in many cases 1
• Avoid surgery in centers without high-volume experience - deep glioma surgery should occur in specialist centers with dedicated neurosurgical oncology teams 1

Recommended Algorithm

For this 25-year-old with 5 cm basal ganglia glioma:

1. If neurologically stable without symptomatic mass effect: Consider stereotactic biopsy first to establish molecular diagnosis, then proceed with adjuvant therapy ± delayed resection based on tumor biology 6, 1

2. If symptomatic with progressive deficits or mass effect: Proceed with open craniotomy using maximal intraoperative adjuncts, accepting that subtotal resection preserving function is superior to aggressive resection causing permanent deficits 1, 2

3. If low-grade glioma confirmed: Pursue maximal safe resection given excellent long-term survival potential in young patients 2, 4

4. If high-grade glioma confirmed: Balance surgical morbidity against modest survival benefit (15% at 2 years), potentially favoring biopsy plus chemoradiation over aggressive resection 2