Wisconsin Criteria for Maxillofacial CT

Why use it

Facial fractures are among the most common injuries requiring emergency department evaluation, constituting approximately 3–5% of all trauma presentations. Missed facial fractures — particularly orbital blow-out fractures, zygomatic fractures, Le Fort fractures, and mandibular fractures — can result in persistent functional deficits (diplopia, malocclusion, restricted mouth opening, facial numbness, enophthalmos) and cosmetic deformity if not identified and treated promptly. Conversely, indiscriminate CT imaging of all facial trauma patients exposes patients to unnecessary radiation (a dedicated facial CT delivers approximately 1–5 mSv) and increases healthcare costs and throughput time. The Wisconsin Criteria provide a clinical framework that identifies which patients need CT while enabling safe clinical management of low-risk presentations without imaging.

About

The Wisconsin Criteria for Maxillofacial CT provide a structured clinical decision rule to identify patients who require computed tomography (CT) imaging of the facial skeleton after blunt facial trauma. The criteria were derived from a retrospective analysis of 4,786 patients presenting with craniomaxillofacial (CMF) trauma at the University of Wisconsin Medical Center and published by Mithani and colleagues in Plastic and Reconstructive Surgery in 2009. The study identified predictable clinical patterns of injury mechanisms and physical examination findings that reliably predict the presence of significant facial fractures requiring CT characterization. Facial CT is the imaging gold standard for characterizing facial fractures — it provides multiplanar reconstruction with excellent bone and soft-tissue detail, enabling accurate classification of fracture patterns (orbital, zygomatic, Le Fort, mandibular, panfacial) and surgical planning. However, CT carries radiation exposure, is resource-intensive, and is not indicated for all facial trauma presentations. The Wisconsin Criteria enable selective, evidence-based use of CT by identifying high-risk features: (1) mechanism of injury (high-energy mechanism independently predicts facial fracture risk); (2) physical examination findings including periorbital ecchymosis, facial bone step deformity or tenderness, midface instability, epistaxis, visible crepitus, and neurological findings such as diplopia or facial paresthesia; and (3) functional abnormalities including malocclusion, restricted mouth opening, and restricted extraocular movements. Any single high-risk criterion is sufficient to indicate maxillofacial CT. These criteria help standardize imaging decisions, avoid unnecessary CT in minor low-energy facial trauma, and ensure that significant injuries are not missed.

When to use

• Any adult or adolescent presenting after blunt facial trauma (assault, motor vehicle collision, fall, sports injury, occupational injury)
• After initial primary survey (ATLS ABCDE approach) — maxillofacial CT assessment applies to hemodynamically stable patients only; unstable patients require immediate resuscitation
• When clinical examination reveals any of the high-risk features listed below — a single criterion is sufficient for CT indication
• When mechanism is high-energy (motor vehicle collision >40 km/h, pedestrian struck, fall >1 meter, assault with weapon, blast or sports injury with significant impact) — strong independent predictor
• NOT indicated as a primary imaging tool in penetrating facial trauma — CT angiography (CTA) should be prioritized to exclude vascular injury; bony imaging follows
• NOT a substitute for careful physical examination — the Wisconsin Criteria are applied AFTER thorough examination of the facial skeleton, including palpation of orbital rims, zygomatic arches, mandible, and midface, and assessment of bite and eye movements
• NOT validated for pediatric patients under 12 years — children have different fracture patterns (greenstick, incomplete), different facial anatomy, and different energy thresholds; pediatric trauma guidelines and clinical judgment should guide imaging in this age group

Formula

Pearls & pitfalls

• Mechanism of injury is the single most important criterion — any high-energy mechanism (MVC >40 km/h, fall >1 meter onto the face, assault with a weapon or fist to the face, sports impact) should prompt serious consideration of CT regardless of initial examination findings, particularly in the intoxicated or altered patient in whom reliable physical examination is not possible.
• Periorbital "raccoon eyes" (bilateral periorbital ecchymosis) classically indicate anterior skull base fracture (basilar skull fracture) — in this context, maxillofacial CT should always be accompanied by CT head.
• Diplopia or restricted extraocular movements should prompt urgent ophthalmology consultation alongside maxillofacial CT — orbital blow-out fractures with entrapped inferior rectus muscle require early surgery (within 48–72 hours) to prevent permanent diplopia from muscle ischemia.
• Subcutaneous emphysema over the face is pathognomonic of a communication between the fracture and an air-containing space (sinus, nasal cavity) — this is a reliable predictor of facial fracture and always indicates CT.
• Facial paresthesia in the infraorbital nerve distribution (cheek, lateral nose, upper lip, upper teeth) indicates orbital floor or zygomatic fracture with nerve involvement — this finding reliably predicts a fracture that requires CT characterization.
• Malocclusion (patient reports their teeth "don't fit together right" after injury) is a highly specific sign of mandibular or Le Fort fracture — always examine occlusion by having the patient close their teeth and asking if it feels normal.
• The "step deformity" on palpation of the orbital rim or zygomatic arch is a reliable predictor of fracture — systematic palpation of all facial buttresses (orbital rims, zygomatic arches, midface, and mandible) is the cornerstone of clinical examination.
• Midface instability (Le Fort test) — grasp the premaxilla (anterior upper alveolus) and gently manipulate while stabilizing the forehead — any movement relative to the skull confirms Le Fort fracture. Le Fort II and III fractures require immediate airway assessment.
• Mandibular fractures may not be apparent on plain films (OPG is the minimum recommended for suspected mandibular injury but has limited sensitivity for condylar and subcondylar fractures — CT is superior). Restricted mouth opening (trismus) <35 mm interincisal distance is strongly suggestive.
• In the intoxicated or uncooperative patient who cannot provide reliable history or tolerate examination, the threshold for CT should be lower — the clinical examination cannot be relied upon in these patients and a witnessed high-energy mechanism should suffice for CT indication.

Next steps

ANY HIGH-RISK CRITERION PRESENT: Order CT maxillofacial (fine-cut axial images with coronal and sagittal reformats; 1–2 mm slice thickness; bone and soft-tissue windows). If concurrent intracranial injury is suspected: CT brain without contrast concurrently (or CT head and face combined protocol). If vascular injury is suspected (penetrating mechanism, expanding hematoma, Zone II neck injury, CN VI palsy): add CTA face/neck. Maxillofacial surgery (oral and maxillofacial surgery, plastics, or ENT/head and neck) consultation for fractures requiring operative management. NO HIGH-RISK CRITERION: CT is NOT indicated by these criteria. Manage clinically — analgesia, ice, observation. Provide clear return precautions: persistent swelling preventing full assessment should prompt reassessment at 48–72 hours when swelling resolves, as some fractures become more apparent. Instruct patient to return for: worsening pain, new diplopia, change in bite, increasing swelling, facial numbness. Soft diet for suspected mandibular injuries without fracture on examination.

Evidence

Mithani SK, St-Hilaire H, Brooke BS, Smith IM, Bluebond-Langner R, Rodriguez ED. Predictable patterns of intracranial and cervical spine injury in craniomaxillofacial trauma: analysis of 4786 patients. Plast Reconstr Surg. 2009;123(4):1293-1301. PMID:19337084. University of Wisconsin derivation cohort — identified predictable clinical and mechanism-based patterns predicting significant CMF injury. Hopper RA, Salemy S, Sze RW. Diagnosis of midface fractures with CT: what the surgeon needs to know. Radiographics. 2006;26(3):783-793. PMID:16702454. CT classification of midfacial fractures. Winegar BA, Murillo H, Tantiwongkosi B. Spectrum of critical imaging findings in complex facial skeletal trauma. Radiographics. 2013;33(1):3-19. PMID:23322827. Comprehensive review of facial trauma CT findings.

References

1. Mithani SK, St-Hilaire H, Brooke BS, Smith IM, Bluebond-Langner R, Rodriguez ED. Predictable patterns of intracranial and cervical spine injury in craniomaxillofacial trauma: analysis of 4786 patients. Plast Reconstr Surg. 2009;123(4):1293-1301. — link
2. Hopper RA, Salemy S, Sze RW. Diagnosis of midface fractures with CT: what the surgeon needs to know. Radiographics. 2006;26(3):783-793. — link
3. Winegar BA, Murillo H, Tantiwongkosi B. Spectrum of critical imaging findings in complex facial skeletal trauma. Radiographics. 2013;33(1):3-19. — link
4. Boyette JR, Pemberton JD, Bonilla-Velez J. Management of orbital fractures: challenges and solutions. Clin Ophthalmol. 2015;9:2127-2137. — link
5. Zimmermann CE, Troulis MJ, Kaban LB. Pediatric facial fractures: recent advances in prevention, diagnosis and management. Int J Oral Maxillofac Surg. 2006;35(1):2-13. — link