Study guide
23.2 Unstable Spine Fractures (03.K)
ABIM Neurocritical Care Subspecialty Certification Exam
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1 Introduction & Exam Overview
1.1 Current Exam Facts 1.2 Eligibility, Practice Pathway, and the IM Training Route 1.3 Format, Scoring, Pearson VUE, and Score Reports 1.4 How to Use This Independent Study Guide
2 ICU Neurologic Exam, Cerebral Physiology, and CSF
2.1 Neurological Examination in the ICU 2.2 Cerebral Physiology, ICP, CBF, and Autoregulation 2.3 CSF Physiology
3 Core Neuropharmacology
3.1 Osmotic Agents 3.2 Anti-Seizure Drugs 3.3 Anesthetics, Sedatives, Analgesia, and Paralytics 3.4 Antihypertensives, Vasopressors, and Inotropes
4 Reperfusion Drugs, Airway, and Ventilation
4.1 Thrombolytics, Anticoagulants, and Antiplatelets 4.2 Reversal of Anticoagulation After Acute Hemorrhage 4.3 Airway Management and Tracheostomy 4.4 Mechanical Ventilation
5 Hemodynamics and Shock
5.1 Hemodynamic Monitoring 5.2 IABP, Temporary VADs, LVAD, and ECMO 5.3 Diagnosis and Management of Shock
6 Nutrition, Temperature, and ICU Prophylaxis
6.1 Nutrition (01.J) 6.2 Temperature Control (01.K) 6.3 ICU Prophylaxis, Delirium, and Early Mobility (01.L)
7 General Trauma
7.1 Emergency Evaluation of Polytrauma, Chest, and Abdominal Trauma 7.2 Long-Bone Fractures and Fat Embolism 7.3 Burns, Electrical Injury, and Hanging/Strangulation
8 Pulmonary Critical Care
8.1 Pulmonary Physiology and ARDS (01.N.1–2) 8.2 PE, Pneumonia, and Pulmonary Edema (01.N.3, 7–8) 8.3 COPD, Asthma, PAH, and Bronchoscopy Basics (01.N.4–6, 9)
9 Cardiovascular Critical Care
9.1 Cardiovascular Physiology, Stress Cardiomyopathy, ACS, and Valves 9.2 Arrhythmias and Pacing 9.3 Acute Aortic Dissection and Cardiac Ultrasound
10 Renal and Infectious Disease
10.1 AKI, RRT, and Renal Drug Dosing 10.2 Acid-Base and Electrolyte Disorders 10.3 Severe Sepsis, Septic Shock, and Infective Endocarditis 10.4 Antimicrobial Use and Infection in the Immunosuppressed
11 Endocrine and Salt-Water Disorders
11.1 Pituitary Apoplexy, DI, and Panhypopituitarism (01.R.1–4) 11.2 SIADH and Cerebral Salt Wasting (01.R.5–6) 11.3 Thyrotoxicosis, Myxedema, Adrenal Crisis, and Dysglycemia (01.R.7–9)
12 Gastrointestinal Critical Care
12.1 GI Physiology, Acute Abdomen, Bleed, Ileus, and Perforation (01.S.1–5) 12.2 Mesenteric Ischemia and Abdominal Compartment Syndrome (01.S.6–7) 12.3 Fulminant Liver Failure, Cirrhosis Decompensation, and Hepatic Dosing (01.S.8–10)
13 Hematologic Disorders
13.1 Anemia, Transfusion, Thrombocytopenia, Coagulopathy, and DIC (01.T.1–4) 13.2 VTE in the Neuro ICU (01.T.5) 13.3 Chemo/Immune, SCT, CAR-T, Sickle Cell, and TMA (01.T.6–10)
14 Neuroimaging
14.1 CT of Brain and Spine 14.2 MRI and CT/MR Perfusion 14.3 Noninvasive Angiography and Catheter Angiography
15 EEG, EMG, and CSF Analysis
15.1 EEG, Standard and Processed (02.B) 15.2 Basic EMG Interpretation (02.G) 15.3 CSF Analysis (02.H)
16 ICP, TCD, and Multimodality Monitoring
16.1 ICP Monitoring (02.C) 16.2 Transcranial Doppler (02.D) 16.3 Brain-Tissue Oxygen and Multimodality Monitoring (02.E–F)
17 Brain Death and Bedside Procedures
17.1 Brain Death Prerequisites and Clinical Exam (02.I) 17.2 Apnea Testing and Ancillary Studies (02.I) 17.3 Vascular Access, Thoracic Echo, and Lung Ultrasound (02.J–L)
18 Coma, Anoxia, and Intracranial Hypertension
18.1 Coma and Other States of Altered Consciousness (03.A) 18.2 Global Anoxia-Ischemia and Post-Resuscitation Encephalopathy (03.A.1) 18.3 Toxidromes, ICU Delirium, and Hypertensive Encephalopathy (03.A.2–4) 18.4 Intracranial Hypertension as a Disease State (03.B)
19 Acute Ischemic Stroke
19.1 IV Reperfusion Therapy (03.C.3) 19.2 Mechanical Thrombectomy Windows and Imaging Selection (03.C.3) 19.3 Malignant Hemispheric Infarction and Basilar Artery Occlusion (03.C.1–2)
20 Intraparenchymal Hemorrhage
20.1 Intracerebral Hematoma (03.D.1) 20.2 Cerebellar Hematoma (03.D.2) 20.3 Intraventricular Hemorrhage (03.D.3)
21 SAH, CVST, and Spinal Cord Infarction
21.1 Aneurysmal Subarachnoid Hemorrhage (03.E.1) 21.2 Non-Aneurysmal SAH (03.E.2) 21.3 Cerebral Venous Sinus Thrombosis (03.F) 21.4 Spinal Cord Infarction (03.G)
22 Vascular Anomalies and Traumatic Brain Injury
22.1 Unruptured Aneurysm, Cavernoma, AVM, and Dural AVF (03.H) 22.2 Diffuse Axonal Injury and Cerebral Contusions (03.I.1–2) 22.3 Epidural Hematoma, Subdural Hematoma, and Penetrating Injury (03.I.3–4, 7) 22.4 Arterial Dissection and Carotid-Cavernous Fistula (03.I.5–6)
23 Spine, Hydrocephalus, and CNS Infection
23.1 Spinal Cord Injury, Central Cord, and Neurogenic Shock (03.J) 23.2 Unstable Spine Fractures (03.K) 23.3 Hydrocephalus and CSF Diversion (03.L) 23.4 Acute CNS Infections (03.M)
24 Seizures and Neuromuscular Emergencies
24.1 Status Epilepticus and Seizures (03.N) 24.2 Guillain-Barré Syndrome (03.O.1) 24.3 Myasthenic Crisis (03.O.2) 24.4 Motor Neuron Disease, Acute Myopathies, Rhabdomyolysis, and CINM (03.O.3–6)
25 Inflammatory Disease, Neuro-Oncology, and Special Populations
25.1 Fulminant Demyelinating Diseases (03.P) 25.2 Autoimmune Encephalitis and Acute Autonomic Hyperactivity (03.Q–R) 25.3 Neuro-Oncology and Treatment Complications (03.S) 25.4 Pregnancy/Post-Partum, Post-Transplant, and Pediatric Patients (03.T–U)
26 Neurosurgical and Perioperative Complications
26.1 Postoperative Seizures, Hemorrhage, Ischemia, and Hyperperfusion (04.A, C, D, H) 26.2 Infection, CSF Leak, and Pneumocephalus (04.B, E, F) 26.3 Complications of EVD and Lumbar Drain (04.G, I)
27 Ethics, Prognostication, and Organ Donation
27.1 Communication, Decision-Makers, Advance Directives, and DNR (05.A, B, G) 27.2 Uncertainties of Prognostication and the Self-Fulfilling Prophecy (05.C) 27.3 Palliative Care, Withdrawal, Withholding, and Futility (05.D–F) 27.4 Donation After Cardiac Death and Care of the Organ Donor (05.H–I)
23.2 Unstable Spine Fractures (03.K)
Key Takeaways Explain This Topic AI
Do not sit up, flex, or log-ignore an uncleared cervical or thoracolumbar fracture; a rigid collar and spine-board precautions stay until imaging and a competent examination say otherwise.
Named unstable cervical patterns include Jefferson (C1 burst), hangman (C2 pars), type II odontoid, flexion teardrop, and jumped (locked) facets.
Thoracolumbar injuries sort into compression, burst, Chance (flexion-distraction), and fracture-dislocation; translation and posterior-ligament failure drive operative instability.
CT defines bony injury in adults; MRI is added for cord signal, disc herniation, and ligamentous injury when the examination is abnormal or CT does not explain the deficit.
Halo immobilization or surgery is for unstable patterns and selected odontoid or hangman fractures; elderly patients often tolerate a halo poorly compared with operative fixation.
Last updated: September 2026
An unstable fracture is a spine that will move under physiologic loads and crush remaining cord or roots. Independent ExamFinch teaching for ABIM Neurocritical Care (outline 03.K) is less about naming every AO subtype and more about not sitting the patient up , recognizing a handful of eponymous cervical injuries, and sorting thoracolumbar trauma into four mechanical families. The neurosurgical and orthopedic teams decide hardware. You decide whether the collar stays, whether MRI is owed, and whether the next “sit to eat” order is malpractice in slow motion.
Clearance is a protocol, not a vibe
Until the cervical spine is cleared, the neck stays in a rigid collar , transfers are logrolled with the head held, and the patient does not sit up . Thoracolumbar precautions follow the same logic: a backboard is for transport, not for a three-day ICU bed (pressure ulcers). Logroll to inspect the back, then get the board out.
In an awake, unintoxicated blunt-trauma patient without a distracting injury, two decision rules can avoid imaging:
Rule You may skip imaging when
NEXUS No midline posterior tenderness, no focal neurologic deficit, normal alertness, no intoxication, no painful distracting injury
Canadian C-spine rule GCS 15, no high-risk factor (age ≥65, dangerous mechanism, paresthesias) or a low-risk factor that allows safe assessment of 45° rotation
If either rule fails, image. In adults, CT from occiput to T1 is the standard bony survey; plain films miss too much. The Canadian rule is more specific than NEXUS in comparative series, but both exist to prevent a missed injury — not to decorate a progress note after you already sat the patient in a chair.
Obtunded, intubated, or unreliable patients cannot be NEXUS-cleared. A high-quality CT that is truly negative for fracture has a very low rate of unstable bony injury. Many neuro ICUs still obtain MRI before collar removal when the examination is unexaminable, there is unexplained deficit, or CT shows a pattern that could hide disco-ligamentous injury. MRI is also the study for cord edema, hematoma, and traumatic disc herniation before you force a closed reduction of jumped facets in an unconscious patient.
Do not declare “C-spine clear, sit up” on a midnight scout film. Do not remove a collar because the brain CT “looked fine.”
Named unstable cervical injuries
Injury Mechanism Why it is dangerous Typical early management theme
Jefferson fracture Axial load through the skull (dive, fall on vertex) C1 ring bursts; stability hangs on the transverse atlantal ligament (TAL) Collar or halo if TAL intact; C1–2 fusion if TAL ruptured or the ring is highly displaced
Hangman fracture Hyperextension-distraction (MVA more often than judicial hanging) Traumatic spondylolisthesis of C2 (bilateral pars/pedicle) Minimally displaced: collar or halo; displaced or C2–3 disc disruption: surgery
Odontoid (dens) Flexion or extension shear Type II (base of dens) has a small cancellous surface and a high nonunion rate Type I and many type III: immobilization; type II: surgery versus halo, especially in the elderly
Flexion teardrop Severe flexion-compression Anterior fragment is the “teardrop”; the body retropulses; posterior ligaments fail; often cord injury Unstable; operative reconstruction is the rule
Extension teardrop Hyperextension avulsion of an anterior-inferior fragment More a ligament/avulsion problem; cord often spared relative to flexion teardrop Often collar if isolated
Jumped (locked) facets Flexion-distraction, rotation Inferior facet jumps over the superior facet of the level below; canal narrows Unilateral: often root injury; bilateral: often cord injury. Reduce (closed if awake and neurologically monitored, or open) after MRI if unconscious; then fuse
Atlanto-occipital dissociation High-energy distraction Craniocervical ligaments fail; often fatal prehospital Stabilize; do not traction like a routine odontoid; occipitocervical fusion if the patient survives
Anderson and D’Alonzo odontoid types: I is the tip (think alar ligament; consider craniocervical instability), II is the waist/base of the dens (most common, most nonunion), III extends into the C2 body (broader cancellous bed, more often heals in a brace or halo). Geriatric type II fractures are a halo hazard: pins, pneumonia, and dysphagia. Many centers prefer early C1–2 fixation rather than a vest the patient cannot live in.
Rule of Spence (summed C1 lateral-mass overhang on the C2 lateral masses greater than about 7 mm) was a plain-film hint of TAL rupture in Jefferson fractures. CT and MRI of the ligament have replaced that as the decision tool. Still recognize the name.
Unilateral jumped facet often presents with a radiculopathy and about one-quarter canal compromise. Bilateral jumped facets often present with cord injury and about one-half canal compromise. Both are unstable. Closed reduction in an awake patient who can report a new deficit is a classic option; an unconscious patient needs MRI so you do not drive a disc into the cord.
Thoracolumbar: four mechanical families
Denis’ three-column language still appears on exams even as AO Spine (A compression, B distraction, C translation) is what spine services write in the chart. Translate both.
Pattern Columns / AO flavour Mechanism Stability Associated injuries
Compression Anterior column; AO A1 Flexion, osteoporotic or traumatic Usually stable if posterior ligaments intact Pain; rarely cord
Burst Anterior and middle; retropulsed bone; AO A3/A4 Axial load Unstable if posterior ligamentous complex fails or there is neurologic deficit from retropulsion Calcaneus/other axial-load fractures
Chance Horizontal through bone and/or ligaments; AO B flexion-distraction Seatbelt: axis of rotation in front of the spine Unstable (posterior tension band fails) Hollow viscus, pancreas, mesenteric tear
Fracture-dislocation All columns; translation/rotation; AO C Shear, high energy Always unstable Cord transection or severe incomplete injury
A compression fracture that is only anterior wedging, neurologically intact, with an intact posterior ligamentous complex, is often a TLSO brace. A burst fracture with a retropulsed fragment, PLC edema on MRI, and an incomplete deficit is a surgical conversation. A Chance fracture on a lap-belt history is not “just a back bruise”: CT the abdomen. A fracture-dislocation is an operative emergency for stability even when the cord is already complete, because remaining roots, skin, and sitting balance still depend on a straight spine.
Thoracolumbar injury classification and severity ( TLICS ) scores morphology, PLC integrity, and neurology. You do not need to memorize every point total for this exam, but you do need to know that a disrupted PLC plus incomplete neurology pushes toward surgery.
Imaging, halo, and surgery — who gets which
CT first for bone. MRI when there is a neurologic deficit, a CT-negative SCI (SCIWORA is more a pediatric term; adults usually have spondylotic compression), suspected ligamentous injury, or before reducing locked facets in an unexaminable patient. MRI also finds epidural hematoma that needs decompression.
Halo vest can hold selected upper cervical injuries (some hangman fractures, some type II/III odontoid fractures) when surgery is not chosen. Pin-site infection, dysphagia, and respiratory restriction make it a poor default in frail elders. Operative fixation is indicated for clearly unstable patterns: bilateral jumped facets, flexion teardrop, fracture-dislocation, burst with PLC failure and deficit, atlanto-occipital dissociation in survivors, and many displaced type II odontoid fractures.
Early decompression (within 24 hours when feasible) is the AO Spine/STASCIS-era theme for SCI with ongoing compression. That is a surgical clock. Your ICU contribution is still MAP, oxygenation, and not converting a burst fracture into a dislocation with a sitting X-ray.
Exam traps
Sitting a combative, uncleared patient “just for a chest X-ray.” Calling a Chance fracture a simple compression because the anterior height loss looks familiar. Treating an extension teardrop like a flexion teardrop (or the reverse). Clearing an intubated polytrauma patient on a single lateral C-spine film. Forgetting the abdominal CT on a Chance fracture. Putting a 85-year-old in a halo for a type II dens fracture because a 1980s protocol said so, when the real choice is surgery versus a well-fitted collar with realistic nonunion counseling.
In practice
A helmeted cyclist is logrolled off a backboard in a collar. CT shows a C1 burst with intact TAL on MRI and no deficit: collar, not an immediate fusion. Another patient has bilateral jumped C5–6 facets and an incomplete cord: MRI, reduction, surgery — not a chair in the hallway. A rear-seat passenger with a lap belt has a horizontal L2 fracture through the pedicles: Chance family, unstable, and the next scan is the abdomen, not a discharge walker.