Modified Brain Injury Guidelines

• The modified Brain Injury Guidelines: safe, sensitive, but not yet specific
• Targeted temperature management to minimise secondary brain injury after cardiac arrest: A systematic review
• Socioeconomic correlates of decompressive craniectomy outcomes for pediatric traumatic brain injury: a meta-epidemiological study
• Bridging the Gap Between Brain Health Guidelines and Real-world Implementation
• Emodin influences pyroptosis-related Caspase 1-GSDMD axis alleviated cerebral ischemia-reperfusion injury in rats
• Development of a 3D ex vivo model of brain-leukemia interaction to study the role of activin A in the central nervous system microenvironment
• Optimization and evaluation of an experimental subarachnoid hemorrhage model in mice
• Clinical Assessment on Days 1-14 for the Characterization of Traumatic Brain Injury: Recommendations from the 2024 NINDS Traumatic Brain Injury Classification and Nomenclature Initiative Clinical/Symptoms Working Group

The BIG project was developed by trauma surgeons to create a simplified, risk-based management algorithm for mild traumatic brain injury (TBI), with the goal of reducing unnecessary:

• ICU admissions
• CT scan repetition
• Neurosurgical consultations

• Stratify patients with mild TBI into clinically meaningful groups
• Guide ED disposition safely
• Reduce healthcare burden without increasing risk

• Retrospective cohort, followed by prospective validation
• Developed at a Level I trauma center in Tucson, Arizona

The BIG project laid the foundation for the later Modified Brain Injury Guidelines (mBIG), which further refined patient selection and integrated into modern neurotrauma protocols.

In a retrospective cohort review, Freeman et al. from the University of Colorado, Aurora published in the Journal of Neurosurgery analyzed the sensitivity and specificity of the modified Brain Injury Guidelines (mBIG)—especially mBIG 3 criteria—to predict neurosurgical intervention, and explored the predictive value of individual radiographic parameters.

→ mBIG 3 criteria showed 99.5% sensitivity, and combined mBIG 2+3 reached 100% sensitivity. → Specificity remains low:

• mBIG 3: 37.2%
• mBIG 2+3: 18.1%

→ Isolated IPH or SAH in mBIG 3 with GCS 13–15 are poor predictors of intervention. → Authors propose eliminating routine repeat head CT in mBIG 1–2 cases.

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➤ Strengths:

• Large sample (n = 1128) over 3.5 years (May 2020–Dec 2023).
• Addresses key clinical issue: reducing unnecessary repeat CTs.
• High sensitivity makes mBIG a safe exclusion tool, especially mBIG 2+3.

➤ Limitations:

• Retrospective design → risk of selection bias and unmeasured confounding.
• Low specificity → risk of overtriage, especially in mBIG 3.
• Single-center → limits external generalizability.
• Sparse detail on intervention timing and type.
• No external validation; subgroup analyses were post hoc.

➤ Interpretation:

• Excellent rule-out utility — captures nearly all patients needing neurosurgical care.
• Poor rule-in capacity — high false positive rate may increase resource use.
• Radiographic IPH/SAH alone, in GCS 13–15 cases, not reliable predictors of need for surgery.

Score: '7.0 / 10' → Strong cohort and relevant clinical insight. → Undermined by retrospective nature, low specificity, and lack of external validation.

Bottom Line for Neurosurgeons: Use mBIG as a reliable safety net to rule out cases unlikely to require neurosurgical intervention. However, in mild TBI with isolated IPH or SAH, conservative observation without early repeat CT may be acceptable — despite mBIG 3 classification.