Case Prep: Odontoid (Type II) Fracture Fixation

Case / Approach Snapshot

• Anatomy at risk: unstable columns, cord/roots, dura, vertebral artery or great-vessel/visceral structures by level, fracture lines, and fixation corridors.
• Operative steps: protect the spine during transfer/positioning, confirm levels and reduction goals, decompress when indicated, instrument/reconstruct stability, verify alignment and hardware, and plan ICU/brace/rehab needs; use the detailed operative sequence and approach notes below as the step-by-step source.
• Rescue plans: neurologic deterioration, reduction failure, vascular/visceral injury, durotomy, blood loss, hardware pullout, infection, and staged anterior/posterior stabilization.
• Figures: review Figures, Imaging & Video and the Curated Image Set; embedded local figures should remain open-access, public-domain, or otherwise reusable with attribution.
• Papers: review High-Yield Literature for seminal sources, modern reviews, and outcome data specific to this page.

One-Liner

[Age]yo [M/F] with a type [II/III] odontoid fracture ([Anderson-D’Alonzo]) following [fall/MVC] planned for [anterior odontoid screw / posterior C1-C2 fusion].

Figures, Imaging & Video

🎥 Operative video — search operative video on YouTube ▸ · The Neurosurgical Atlas ▸

🧭 Operative approach: Posterior cervical approach — posterior C1-C2 fixation/exposure principles when anterior odontoid screw is not the chosen strategy.

Neurosurgical Atlas · AO Spine / Surgery Reference · Radiopaedia · PubMed Central — operative figures © linked; see media-sources.md

High-Yield Literature

• Predicting Mortality Following Odontoid Fracture Fixation in Elderly Patients: CAADS-16 Score — ElNemer W. Global spine journal 2025. PubMed
• Outcomes of Odontoid Process Fracture Surgery — Sowa D. Ortopedia, traumatologia, rehabilitacja 2023. PubMed
• Odontoid process type II and III fracture fixation using bone allograft screws versus cannulated screws: a biomechanical study — Benca E. Archives of orthopaedic and trauma surgery 2025. PubMed
• Biomechanics of odontoid fracture fixation. Comparison of the one- and two-screw technique — Sasso R. Spine 1993. PubMed
• Percutaneous anterior odontoid screw fixation technique. A new instrument and a cadaveric study — Kazan S. Acta neurochirurgica 1999. PubMed
• Computed tomographic evaluation of odontoid process: implications for anterior screw fixation of odontoid fractures in an adult population — Daher MT. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society 2011. PubMed
• Cervical Spine Navigation and Enabled Robotics: A New Frontier in Minimally Invasive Surgery — Lebl DR. HSS journal : the musculoskeletal journal of Hospital for Special Surgery 2021. PubMed
• Medical devices of the head, neck, and spine — Hunter TB. Radiographics : a review publication of the Radiological Society of North America, Inc 2004. PubMed
• Salvage of failed odontoid fixation through anterior C1/C2 transarticular screws — Salem KM. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society 2015. PubMed
• Odontoid Fusion — Walker CT. Acta neurochirurgica. Supplement 2019. PubMed

Curated Image Set

Open-access figures are embedded from PubMed Central articles and kept unique to this guide.

Figure 2.. ROC curves for CAADS-16 score and ASA classification. The AUC is displayed in the legend, and the cut off values are represented in the squares of the curve. The ASA classification was… Source: Predicting Mortality Following Odontoid Fracture Fixation in Elderly Patients: CAADS-16 Score — Global Spine Journal 2023; CC BY-NC-ND.

FIG. 1.. A: Identifying the joint space below the lateral mass of the atlas (anatomical drawing). B: Inserting osteotome for manipulation (anatomical drawing). C: Rotating the osteotome to open… Source: Unstable odontoid fractures: technical appraisal of anterior extrapharyangeal open reduction internal fixation for irreducible unstable odontoid fractures. Patient series — Journal of Neurosurgery: Case Lessons 2021; CC BY-NC-ND.

FIG. 2.. A: Posteriorly displaced impacted fracture (anatomical image). B: Impaling the anterior arch of the atlas and distal fracture fragment with a tap (anatomical image). C: Repositioning the… Source: Unstable odontoid fractures: technical appraisal of anterior extrapharyangeal open reduction internal fixation for irreducible unstable odontoid fractures. Patient series — Journal of Neurosurgery: Case Lessons 2021; CC BY-NC-ND.

History of Present Illness

• Chief complaint: Neck pain after trauma; may have minimal/no deficit (or high cervical cord injury)
• Mechanism, neurological status, associated injuries (especially elderly fall — common)
• Anderson-D’Alonzo: Type I (tip, stable), Type II (base — most common, high nonunion), Type III (into body, better union)
• Displacement, angulation, direction; chronicity

Imaging Review

CT cervical (thin-cut, reconstructions)

• Fracture type, displacement, angulation (anterior vs posterior), comminution
• C1-C2 anatomy for screw planning (vertebral artery course, C2 pedicle/pars, C1 lateral mass)
• Transverse atlantal ligament integrity (CT/MRI)

  MRI

• Ligament integrity (transverse ligament — if disrupted, screw alone insufficient), cord signal, soft tissue

  CTA

• Vertebral artery anatomy (high-riding VA, anomalies — affects C2 screw safety)

  X-ray (flexion/extension if stability unclear, with caution)

Labs

• CBC, BMP, Coags, Type and screen

Neurological Examination

• Full exam (high cervical — respiratory, all extremities), document deficits

Surgical Planning

Case Logistics, OR Needs & Orders

• OR table/bed: Jackson/Allen/open-frame radiolucent table, or ProAxis/hinged table when sagittal alignment adjustment is useful; keep abdomen free for venous decompression.
• OR setup: spine table with log-roll precautions, fluoroscopy/O-arm/navigation, traction/Mayfield when cervical, posterior/anterior implant trays, decompression instruments, cell saver/blood for large constructs, and IONM before positioning when feasible.
• Special needs: arterial line, Foley, type/cross, MAP augmentation for acute SCI per local protocol, no long paralytic when MEPs are needed, anticoagulation/reversal plan, and airway strategy for unstable cervical injuries.
• Immediate postop orders: serial ASIA/neuro checks, MAP goal/duration if SCI, CT/X-rays for hardware/alignment, brace/collar orders, drain care, DVT prophylaxis timing, bowel/bladder/skin care, and early rehab/SCI consult.

Procedure Selection

• Anterior odontoid screw: preserves C1-C2 rotation; for reducible Type II fractures with favorable oblique pattern (anterosuperior-posteroinferior), intact transverse ligament, good bone; contraindicated in osteoporosis, comminution, irreducible, unfavorable fracture line, disrupted transverse ligament, barrel chest/kyphosis (trajectory)
• Posterior C1-C2 fusion (Goel-Harms C1 lateral mass + C2 pedicle screws; or Magerl transarticular): for irreducible, comminuted, transverse ligament disruption, nonunion, poor bone; sacrifices rotation
• Elderly: rising use of surgical fixation vs hard collar (nonunion common but fibrous union often tolerated)

Position

• OR table/bed: Jackson/Allen/open-frame radiolucent table, or ProAxis/hinged table when sagittal alignment adjustment is useful; keep abdomen free for venous decompression.
• Anterior screw: supine, neck slightly extended, Mayfield/traction for reduction, biplanar fluoroscopy (AP + lateral, open-mouth), radiolucent setup
• Posterior C1-C2: prone, Mayfield, neck neutral, reduce, fluoroscopy/navigation

Key Surgical Steps (Anterior Odontoid Screw)

1. Reduce fracture (positioning/traction), confirm on fluoroscopy
2. Anterior cervical (Smith-Robinson-type) exposure to C2-C3 level, trajectory from the anteroinferior C2 body
3. Entry at anteroinferior C2 endplate, guidewire up the odontoid across the fracture to the tip under biplanar fluoroscopy
4. Cannulated drill, tap, place lag screw (1 or 2 screws) to compress fracture across the fracture line into the dens tip
5. Confirm compression/reduction and screw position (both fluoro planes)
6. Closure

Key Surgical Steps (Posterior C1-C2, Goel-Harms)

1. Prone, expose C1 posterior arch and C2
2. C1 lateral mass screws (entry below the posterior arch, protect C2 nerve root/venous plexus)
3. C2 pedicle/pars screws (assess VA on CTA — high-riding VA contraindicates pedicle screw → use pars/translaminar)
4. Reduce C1 on C2, place rods, lock
5. Decorticate, bone graft (autograft/allograft) for fusion
6. Closure

Critical Anatomy & Structures at Risk

1. Vertebral arteries (C2 screw trajectory — high-riding VA; C1-C2 region) — catastrophic
2. Spinal cord / cervicomedullary junction — high cervical, narrow margin
3. C2 nerve root / venous plexus (C1 lateral mass screw — bleeding)
4. Esophagus/airway (anterior approach), hypoglossal/superior laryngeal nerves (high anterior)
5. Transverse atlantal ligament (competence determines construct)

Equipment

• Anterior odontoid screw set (cannulated lag screws) OR C1-C2 posterior screw/rod system
• Biplanar fluoroscopy / navigation, traction/reduction tools
• Bone graft (posterior fusion), microscope/loupes

Monitoring

• SSEPs/MEPs (high cervical), especially during positioning/reduction; awake fiberoptic intubation if unstable/myelopathic

Anesthesia

• Awake fiberoptic intubation (unstable C-spine, avoid hyperextension), MAP support, arterial line, in-line stabilization

Potential Complications

1. Vertebral artery injury (C2 screw), cord/cervicomedullary injury
2. Nonunion (esp. Type II, elderly, anterior screw), screw pullout/malposition
3. Dysphagia/airway (anterior), C2 neuralgia, loss of rotation (posterior fusion)
4. Hardware failure, adjacent issues

Operative Note Template

Preoperative Diagnosis: Type [II] odontoid (dens) fracture [displaced ___ mm], craniocervical instability

Postoperative Diagnosis: Same

Procedure: [Anterior odontoid screw fixation / Posterior C1-C2 instrumented fusion (Goel-Harms — C1 lateral mass + C2 pedicle screws)] for type [II] odontoid fracture

Surgeon / Assistant: Anesthesia: General endotracheal (awake fiberoptic intubation) EBL / Fluids: Implants: [Cannulated lag odontoid screw(s) / C1 lateral mass and C2 pedicle screws and rods — system/sizes; bone graft] Monitoring: SSEP / MEP — stable [note any change with positioning/reduction] Complications: None

Indications: [Age]yo [M/F] with a type II odontoid fracture after [mechanism], [reducible, intact transverse ligament, favorable fracture line → anterior screw / irreducible/comminuted/disrupted transverse ligament/poor bone → posterior C1-C2 fusion]. CTA showed [no high-riding VA / VA anatomy permitting planned screws]. Risks/benefits/alternatives (including collar immobilization and nonunion risk) discussed.

Description of Procedure: After consent and time-out, awake fiberoptic intubation was performed to protect the unstable cervical spine, and neuromonitoring baselines were confirmed before and after positioning. The fracture was reduced [with positioning/traction] and verified on biplanar fluoroscopy.

Final fluoroscopy confirmed satisfactory reduction and hardware. Neuromonitoring was stable throughout. Closure was performed in layers [± drain]. The patient was awakened, neurologically [at baseline], and transferred in stable condition.

Postoperative Plan

• ICU/step-down, neuro checks (high cervical — respiratory), airway monitoring (anterior — swelling)
• CT postop (screw position, reduction), cervical collar per construct/surgeon
• DVT prophylaxis, pain control, dysphagia/aspiration precautions (anterior)
• Follow-up CT for union; counsel re: nonunion risk; flexion/extension films later

Chief-Level Case Review

Use these as the senior-level mental model for Odontoid (Type II) Fracture Fixation:

• Decision point: Treat physiology while preparing the room: airway, reversal, transfusion, ICP/CPP, sodium/osmolality, temperature, and repeat imaging drive timing as much as the scan finding.
• Technical lever: Know the operative priority: decompression, hemorrhage control, debridement, dural closure, reconstruction, stabilization, or contamination control.
• Bailout: Plan for swelling and coagulopathy: bone flap decision, duraplasty size, drain/EVD need, hemostatic adjuncts, and ICU handoff should be decided early.
• Postop watch: Postop failure modes are predictable: expanding hematoma, malignant edema, seizure, infection, CSF leak, venous sinus injury, and missed associated spine/vascular injury.

Common Pimp Questions

Use these to pressure-test preparation for Odontoid (Type II) Fracture Fixation:

1. What neurologic level and root are responsible for the presenting deficit?
2. What is the decompression target and how will you know it is adequately decompressed?
3. What instability, deformity, bone-quality, or fusion variable changes the construct?
4. What vascular, visceral, dural, or neural structure is the main structure at risk?
5. What postop brace, drain, mobilization, MAP, antibiotic, and DVT plan should be ordered?

Attending Preference Variables

Items that commonly vary by surgeon or institution:

• Positioning frame, arms, traction, and localization workflow: [attending-specific]
• Navigation/robot/fluoro use, screw system, graft/biologic choice, and drain threshold: [attending-specific]
• Neuromonitoring modality and MAP goal for myelopathy, deformity, or cord-risk cases: [attending-specific]
• Brace, Foley, antibiotics, mobilization, and DVT prophylaxis timing: [attending-specific]