Modified Brain Injury Guidelines [Neurosurgery Wiki]

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====== Modified Brain Injury Guidelines ======

{{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/1DuyIu5gTabg1is1spU0pVIS8P5ZTRvXtg6IqHuk2O38yziY9a/?limit=15&utm_campaign=pubmed-2&fc=20250705122312}}

===== 🧠 The BIG (Brain Injury Guidelines) Project =====

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

===== 📋 BIG Categories =====

^ **Category** ^ **Definition** ^ **Recommended Management** ^
| **BIG 1** | Normal neurological exam + normal CT or very minor findings | Discharge from ED with observation instructions |
| **BIG 2** | Minor CT abnormalities (e.g., small SAH or contusion), normal neuro exam, no coagulopathy | Admit to floor for observation; repeat CT if symptoms |
| **BIG 3** | Abnormal neurological exam, coagulopathy (e.g., INR >1.4), or significant CT findings | Admit with neurosurgical consultation; possible intervention |

===== 🎯 Goals =====
  * Stratify patients with **mild TBI** into clinically meaningful groups
  * Guide ED disposition safely
  * Reduce healthcare burden without increasing risk

===== 🔬 Study Design =====
  * Retrospective cohort, followed by prospective validation
  * Developed at a Level I trauma center in **Tucson, Arizona**

===== 📌 Legacy =====
> 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.


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===== Retrospective cohort reviews =====

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.

((Freeman LM, Mecum A, Cripps MW, Lennarson PJ. The [[modified Brain Injury Guidelines]]: safe, sensitive, but not yet specific. *J Neurosurg.* 2025 Jul 4:1–10. doi:10.3171/2025.3.JNS242874. PMID: 40614279.))

----

==== 🧠 Critical Review ====

**➤ 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.

----

==== ✅ Verdict & Takeaway ====

**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.