The Simpson grade: abandon the scale but preserve the message

Area of Science:

• Neurosurgery
• Oncology
• Surgical Pathology

Background:

• The Simpson grading scale, established in 1957, has been the standard for assessing meningioma resection extent.
• This scale relies on subjective intraoperative visual assessment, leading to inaccuracies and controversy.
• Its relevance is diminished by advancements like routine postoperative MRI and understanding of tumor variability.

Purpose of the Study:

• To critically evaluate the continued relevance of the Simpson grading scale in contemporary meningioma surgery.
• To highlight the limitations of subjective assessment in determining surgical extent.
• To advocate for modern, objective criteria in meningioma resection.

Main Methods:

• Review of historical and current literature on meningioma surgical grading and outcomes.
• Analysis of the limitations of the Simpson scale in light of technological advancements (e.g., MRI, molecular imaging).
• Discussion of tumor-specific factors (location, biology) influencing resection goals.

Main Results:

• The Simpson scale's subjective nature and historical context limit its accuracy and applicability.
• Tumor location, infiltration patterns, and molecular biology necessitate individualized surgical goals.
• Routine postoperative MRI and advanced imaging like [68Ga]-DOTATATE-PET offer objective assessment.

Conclusions:

• The Simpson scale is no longer a relevant universal measure for meningioma resection.
• Maximal safe resection, guided by objective criteria and personalized to tumor characteristics, should be the surgical goal.
• Modern neurosurgery should embrace advanced imaging and molecular techniques for optimal meningioma management.