Skull Base Trauma Disclosures & CSF Leaks ASHNR 2017 No relevant disclosures Kristen Lloyd Baugnon, M.D. Department of Radiology and Imaging Sciences Division of Neuroradiology Objectives Skull base trauma ! Describe patterns of skull base fractures ! Up to 16% of CHI ! High velocity impact ! Identify complications requiring ! Penetrating trauma <10% ! Assoc w complex facial and orbital fractures multidisciplinary treatment ! Detection important ! Tx depends on IC injury and complications ! Algorithim for CSF Leak Diagnosis and Evaluation ! Multidisciplinary care ! Develop a checklist Detection of skull base fx Detection of skull base fx ! Can be challenging if ! Thin section bone nondisplaced algorithm MDCT with reformats ! NCCT Clues: ! Coronal, Sagittal, tbone ! Pneumocephalus ! 3D VR reformats ! Blood in sinuses/mastoids ! Curved MIP reformats ! Overlying ST swelling ! Beware of pseudofractures! ! Freq missed: Occipital condyle, ACF, tbone Baugnon KL et al NI Clinics, Aug 2014 Supraorbital foramen Baugnon KL et al NI Clinics, Aug 2014 and sphenofrontal suture Suture diastasis Patterns of SB Fracture ! Patterns seen depend on direction of impact ! Many different classification systems ! Location in skull base (ACF, MCF, tbone, PCF) ! Assoc complications ! Fractures often complex/mixed Baugnon KL et al NI Clinics, Aug 2014 Baugnon KL et al NI Clinics, Aug 2014 Anterior cranial fossa trauma Anterior skull base fractures ! Direct frontal trauma ! “Frontobasal” fractures ! Frontal (upper 1/3 face) ! Basal (ant skull base) ! Type I-III fractures ! Type I – medial, linear ! Type II – lateral ! Type III – mixed, comminuted Type I Frontobasal fracture Baugnon KL et al NI Clinics, Aug 2014 Manson et al Plast Recon Surg 2009 Anterior skull base fractures Anterior skull base fractures ! Direct frontal trauma ! Direct frontal trauma ! “Frontobasal” fractures ! “Frontobasal” fractures ! Frontal (upper 1/3 face) ! Frontal (upper 1/3 face) ! Basal (ant skull base) ! Basal (ant skull base) ! Type I-III fractures ! Type I-III fractures ! Type I – medial, linear ! Type I – medial, linear ! Type II – lateral ! Type II – lateral ! Type III – mixed, ! Type III – mixed, comminuted comminuted Type II Frontobasal fracture Type III Frontobasal fracture ! Types II& III more assoc with ! Types II& III more assoc with complications Baugnon KL et al NI Clinics, Aug 2014 complications Baugnon KL et al NI Clinics, Aug 2014 Middle cranial fossa trauma Central skull base fractures ! Oblique pattern: frontal impact extending to central skull base ! Facial fxs, type II/III FB fxs, CSF leak ! Transverse: lat impact ! CN and vascular injury ! Often assoc with tbone fxs ! Anterior vs posterior Oblique central skull base fracture Baugnon KL et al NI Clinics, Aug 2014 Central skull base fractures Central skull base fractures ! Oblique pattern: frontal ! Oblique pattern: frontal impact extending to impact extending to central skull base central skull base ! Facial fxs, type II/III FB ! Facial fxs, type II/III FB fxs, CSF leak fxs, CSF leak ! Transverse: lat impact ! Transverse: lat impact ! CN and vascular injury ! CN and vascular injury ! Often assoc with tbone ! Often assoc with tbone Anterior Transverse fx fxs fxs ! Anterior vs posterior Baugnon KL et al NI Clinics, Aug 2014 ! Anterior vs posterior Posterior Transverse fx Baugnon KL et al NI Clinics, Aug 2014 Posterior skull base trauma Posterior skull base fractures ! Lateral and/or posterior blow to occiput ! Occipital bone, +/-ext to petrous t bone and FM ! No simple classification scheme ! T bone fxs described independently Baugnon KL et al NI Clinics, Aug 2014 Clivus fractures Clivus fractures ! Central and posterior skull ! Central and posterior skull base fractures base fractures ! High mortality ! High mortality ! Brainstem, NV ! Brainstem, NV ! Transverse ! Transverse ! Lateral blow ! Lateral blow ! CN/ICA injury (CN VI) ! CN/ICA injury (CN VI) Baugnon KL et al NI Clinics, Aug 2014 Transverse Clival fx Baugnon KL et al NI Clinics, Aug 2014 Transverse Clival fx Clivus fractures Clivus fractures ! Central and posterior skull ! Central and posterior skull base fractures base fractures ! High mortality ! High mortality ! Brainstem, NV ! Brainstem, NV ! Transverse ! Transverse ! Lateral blow ! Lateral blow ! CN/ICA injury (CN VI) ! CN/ICA injury (CN VI) ! Longitudinal ! Longitudinal ! Axial loading ! Axial loading ! VB/CC jxn injury, retroclival ! VB/CC jxn injury, retroclival hematoma hematoma Baugnon KL et al NI Clinics, Aug 2014 Longitudinal Clival fx Baugnon KL et al NI Clinics, Aug 2014 Longitudinal Clival fx Complications of SB trauma Intracranial injury ! IC injuries common – high ! Depend on location velocity impact ! Intracranial ! Multicompartmental ! Vascular (MCF & PCF) hemorrhage, parenchymal ! CN contusions, DAI ! ACF: CN II (Anosmia) ! MCF: CN II, III, IV, V, VI ! Tbone: CN VII, VIII ! PCF: CN IX, X, XI, XII ! CSF leak (ACF, MCF) Intracranial injury: MCF Intracranial injury: MCF ! Anterior MCF epidural ! Anterior MCF epidural hematoma hematoma ! Greater wing sphenoid fx ! Greater wing sphenoid fx ! Benign – venous ! Benign – venous (sphenoparietal sinus) (sphenoparietal sinus) ! Self limited ! Self limited ! Lateral MCF epidural – middle meningeal artery Baugnon KL et al NI Clinics, Aug 2014 Venous epidural hematoma Baugnon KL et al NI Clinics, Aug 2014 Arterial epidural hematoma Intracranial injury: PCF Vascular Injury: Venous ! Posterior Fossa Epidural ! Traumatic venous sinus Hematoma (PFEDH) thrombosis ! Most common IC comp ! 55% of fxs through assoc with posterior skull jugular bulb/sigmoid base fx sinus ! Venous etiology ! Transverse and sagittal sinus less common ! Children ! ↑ ICP, venous ! Can expand rapidly hemorrhage, infarct ! May require (7%), dural AVF decompression Delgado AJE et al. Radiology 2010 Baugnon KL et al NI Clinics, Aug 2014 Vascular Injury: Venous Vascular Injury: Venous ! Traumatic venous sinus ! Traumatic venous sinus thrombosis thrombosis ! 55% of fxs through ! 55% of fxs through jugular bulb/sigmoid jugular bulb/sigmoid sinus sinus ! Transverse and sagittal ! Transverse and sagittal sinus less common sinus less common ! ↑ ICP, venous ! ↑ ICP, venous hemorrhage, infarct hemorrhage, infarct (7%), dural AVF Non contrast head CT (7%), dural AVF CTA/CTV Delgado AJE et al. Radiology 2010 Delgado AJE et al. Radiology 2010 Traumatic dural venous sinus thrombosis Traumatic dural venous sinus thrombosis vs extrinsic compression vs extrinsic compression Baugnon KL et al NI Clinics, Aug 2014 Traumatic dural venous sinus thrombosis Vascular injury - BCVI vs extrinsic compression ! Common comp (8.5%) ! MCF & PCF ! ICA injuries ! York et al: Fractures through carotid canal 35% PPV for ICA injury: 35% PPV ! Modified Denver criteria ! CTA ! Stroke risk decreases with Baugnon KL et al NI Clinics, Aug 2014 anticoagulation ! Vertebrobasilar injuries ! Clivus, occiput, occipital condyle Vascular injury: CC Fistula Cranial Nerve Injury: ACF ! Traumatic direct ! Anosmia (CN I) connection btwn ICA and ! Overall incidence of 7%, cav sinus increased in ACF injuries ! High flow fistula ! Esp cribriform plate ! Exophthalmos, bruit, ! Frontal lobe contusions chemosis, vision loss, ! CSF leak and repair ophthalmoplegia ! Only 10% recover sense ! Acute or delayed of smell, often delayed ! DSA diagnostic & therapeutic Baugnon KL et al NI Clinics, Aug 2014 Baugnon KL et al NI Clinics, Aug 2014 Cranial nerve injury: MCF CN Injury: PCF ! Acute or delayed presentation ! Jugular foramen: IX, X, XI ! Delayed: Stretching/edema, ! Hypoglossal canal better prognosis (occipital condyle): XII ! Optic nerve canal: II ! SOF:III, IV, V1, VI ! Orbital apex syndrome ! Sella: bitemporal heminaopsia (chiasm) ! Cav sinus/clivus: III, IV, V1, Baugnon KL et al NI Clinics, Aug 2014 V2, VI Baugnon KL et al NI Clinics, Aug 2014 CSF Leak Suspected CSF Leak ! 10-30% of skull base fxs ! Beta 2 transferrin (beta trace protein) assay ! Comminuted fxs ! First screening test “gold standard” ! Type II/III FB fxs, tegmen, ! Protein specific to CSF sphenoid ! Unequivocal evidence to support use ! Pneumocephalus ! High sensitivity and specificity ! CSF otorrhea & rhinorrhea ! Patient collects in testtube ! Often resolves ! stores room temp or fridge spontaneously ! Requires only a few drops (0.5 -1 cc) ! Surgery for persistent leak ! Limitations: ! Intermittent or no leak (unable to collect) ! Delayed presentation ! False postive (rare!) Liver failure Baugnon KL et al NI Clinics, Aug 2014 Imaging evaluation HRCT ! Goals of imaging: ! Standard of care – first line ! LOCALIZE the leak ! Localize osseous defect (s): 95% Sensitivity ! Characterize size of defect ! Do not need active leak to see defect ! Assess for meningocele ! Confirm diagnosis ! Images used for intraop guidance ! Assess for underlying cause ! MDCT : Thin slices (< 1mm) with reformats ! No definite imaging gold standard ! Image sinuses and mastoids ! Difficult diagnosis ! Manipulate data on workstation, optimize W/L settings ! Lacking randomized controlled trials ! Measure defect in mutiple planes ! Correlates with size of defect within 2 mm in 75% in one ! CT/MRI/cisternography (NM, CT, MR) study HRCT – Imaging findings HRCT – Imaging findings ! Nondependent soft tissue in nasal cavity or ME cavity, adj to bony defect ! Concerning for cephalocele ! Consider MRI Lloyd K, et al Radiology 2008 Osseous defect with fluid level in sinus or mastoid HRCT 42 yo F w remote h/o trauma ! If only one defect, and positive B2 transferrin ! Surgery ! Limitations: ! Defect