SUMMARY Odontoid Fractures are relatively common fractures of the C2 (axis) dens that can be seen in low energy falls in elderly patients and high energy traumatic injuries in younger patients. Diagnosis can be made with standard lateral and open-mouth odontoid radiographs. Some fractures may be difficult to visualize on Xrays and require a CT scan to diagnose. MRI is rarely indicated as these fractures are usually not associated with neurologic symptoms. Treatment may be nonoperative or operative depending on the Anderson and D'Alonzo type and risk factors for nonunion. Patient older than 80 have a high morbidity and mortality regardless of nonoperative or operative treatment. Epidemiology Incidence most common fracture of the axis account for 10-15% of all cervical fractures most common cervical spine fractures in the elderly Demographics occur in bimodal fashion in elderly and young patients elderly common, often missed, and caused by simple falls associated with increased morbidity and mortality compared to younger patients with this injury young patients result from blunt trauma to head leading to cervical hyperflexion or hyperextension children rare and almost occur at site of basilar synchondrosis Etiology Pathophysiology mechanism displacement may be anterior (hyperflexion) or posterior (hyperextension) anterior displacement is associated with transverse ligament failure and atlanto-axial instability posterior displacement caused by direct impact from the anterior arch of atlas during hyperextension biomechanics a fracture through the base of the odontoid process severely compromises the stability of the upper cervical spine. Associated conditions Os odontoideum etiology previously thought to be due to failure of fusion at the base of the odontoid evidence now suggests it may represent the residuals of an old traumatic process imaging appears like a type II odontoid fx on xray treatment observation Anatomy Osteology axis has odontoid process (dens) and body contains a transverse foramen which vertebral artery travels through embryology develops from five ossification centers subdental (basilar) synchondrosis is an initial cartilaginous junction between the dens and vertebral body that does not fuse until ~6 years of age secondary ossification center appears at ~ age 3 and fuses to the dens at ~ age 12 Arthrology C1-Dens anterior dens articulates with anterior arch of C1 CI-C2 articulation is a diarthrodial joint that provides C2-3 joint participates in subaxial (C2-C7) cervical motion Ligaments occipital-C1-C2 ligamentous stability provided by the odontoid process and its supporting ligaments transverse ligament primary stabilizer of atlantoaxial joint limits anterior translation of the atlas apical ligaments limit rotation of the upper cervical spine alar ligaments limit rotation of the upper cervical spine Blood Supply a vascular watershed exists between the apex and the base of the odontoid apex supplied by branches of internal carotid artery base supplied from branches of vertebral artery the limited blood supply in this watershed area is thought to affect healing of type II odontoid fractures. Kinematics Normal Cervical Kinematics Flexion/Extension Rotation Lateral Bend Occipitocervical joint (OC) 50 4 8 Atlantoaxial joint (C1-2) 10 50 0 Subaxial Spine (C3-7) 50 50 60 Total Motion (degrees) 110 100 68 Classification Anderson and D'Alonzo Classification Type I Oblique avulsion fx of tip of odontoid. Due to avulsion of alar ligament. Although rare,atlantooccipital instability should be ruled out with flexion and extension films . Type II Fracture through waist (high nonunion rate due to interruption of blood supply). Type III Fx extends into cancellous body of C2 and involves a variable portion of the C1-C2 joint. Grauer Classification of Type II Odontoid fractures Type IIA Nondisplaced/minimally displaced with no comminution. Treatment is external immobilization Type IIB Displaced fracture with fracture line from anterosuperior to posteroinferior. Treatment is with anterior odontoid screw (if adequate bone density). Type IIC Fracture from anteroinferior to posterosuperior, or with significant comminution. Treatment is with posterior stabilization. Presentation Symptoms neck pain worse with motion, especially rotation dysphagia may be present when associated with a large retropharyngeal hematoma Physical exam neurologic deficits very rare due to large cross-section area of spinal canal at this level Imaging Radiographs required views AP, lateral, open-mouth odontoid view of cervical spine optional views flexion-extension radiographs are important to diagnose occipitocervical instability in Type I fractures and Os odontoideum instability defined as atlanto-dens-interval (ADI) > 10mm space available for cord (SAC) < 13mm findings fx pattern best seen on open-mouth odontoid CT study of choice for fracture delineation and to assess stability of fracture pattern CT angiogram required to determine location of vertebral artery prior to posterior instrumentation procedures MRI indicated if neurologic symptoms present Treatment Treatment Overview Table Type I Collar Type II (age < 40) Halo Vest Type II (40-80) Surgery Type II (> 80 years) Collar Type III Collar Nonoperative observation alone indications Os odontoideum assuming no neurologic symptoms or instability hard cervical orthosis indications Type I Type II in elderly who are not surgical candidates union is unlikely, however a fibrous union should provide sufficient stability except in the case of major trauma Type III no evidence to support Halo over hard collar technique typically worn for 6-12 weeks halo immobilization indications Type II young patient with no risk factors for nonunion contraindications elderly patients do not tolerate halo (may lead to aspiration, pneumonia, and death) technique typically work for 6-12 weeks Operative posterior C1-C2 fusion indications Type II fractures with risk factors for nonunion indicated in patient 50-80 Type II/III fracture nonunions Os odontoideum with neurologic deficits or instability anterior odontoid screw indications Type II fractures with risk factors for nonunion AND acceptable alignment and minimal displacement (reduction obtained) anterior oblique fracture pattern fracture line is perpendicular to screw trajectory patient body habitus must allow proper screw trajectory outcomes associated with higher failure rates than posterior C1-2 fusion transoral odontoidectomy indications severe posterior displacement of dens with spinal cord compression and neurologic deficits rarely performed due to high complication rate C1 laminectomy typically provides sufficient decompression of the spinal canal and is preferred Techniques Halo immobilization complications pin site infection initial superficial pin infection can be treated with tightening and oral antibiotics C1-C2 posterior fusion approach posterior midline cervical approach stabilization technique sublaminar wiring techniques (Gallie or Brooks) require postoperative halo immobilization and rarely used posterior C1-C2 segmental fixation C1 lateral mass screws 10 degrees medial, 22 degrees cephalad avoid perforation of anterior cortex of C1 lateral mass due to potential internal carotid arteryinjury C2 fixation options include C2 laminar screws C2 pedicle screws C2 pars scews (most common) posterior C1-C2 transarticular screws construct contraindicated in patients with an aberrant vertebral artery outcomes C1-C2 fusion will lead to 50% loss of neck motion Higher fusion rate in elderly compared to anterior fusion Anterior odontoid screw approach anterior approach to cervical spine technique single screw adequate pros & cons associated with higher failure rate than posterior C1-2 fusion advantage is preservation of atlantoaxial motion Transoral odontoidectomy technique usually combined with posterior stabilization procedure Complications Nonunion overall incidence 33% (up to as high as 88% in some studies) risk factors Type II fractures with posterior displacement ( > 2 mm) strongest predictor of nonunion age > 40 years ≥ 5 mm displacement (>50% nonunion rate) delay in treatment ( > 4 days) angulations > 10° smoker Mortality overall patient > 80 year of age do poorly with operative or nonoperative treatment especially with halo orthosis
QUESTIONS 1 of 23 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (SBQ18SP.4) A 72-year-old patient fell from standing height approximately 10 days ago. The patient's neck pain continued to worsen over the last 10 days but has not experienced any associated arm pain or weakness, nor any loss of dexterity. Figure A is her CT scan of the cervical spine during the office visit. Surgical treatment is recommended, but the patient prefers to avoid surgery. The patient is at an increased risk of which of the following complications with nonoperative treatment as opposed to operative treatment? QID: 211146 FIGURES: A Type & Select Correct Answer 1 Vertebral artery occlusion 1% (12/1881) 2 Fracture nonunion 90% (1687/1881) 3 Dysphagia 2% (43/1881) 4 Progressive Myelopathy 6% (116/1881) 5 Cervical Radiculopathy 1% (14/1881) L 4 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (SBQ18SP.6) An active 79-year-old male fell from standing height and noticed immediate neck pain. Examination in the emergency department reveals 5/5 motor in bilateral upper and lower extremities. Current imaging is shown in Figures A-C. The patient undergoes treatment that included closed reduction under anesthesia immediately followed by a posterior C1-2 fusion utilizing lateral mass screws at C1 and pedicle screws at C2. Which of the following statements is true regarding this treatment approach? QID: 211168 FIGURES: A B C D Type & Select Correct Answer 1 It will increase the rate of nonunion compared to nonoperative treatment. 2% (45/1983) 2 It will increase the rate of dysphasia compared to treatment in a halo immobilization. 5% (108/1983) 3 It will decrease mortality compared to nonoperative treatment. 78% (1555/1983) 4 It has a decreased fusion rate compared to an anterior surgical approach 8% (162/1983) 5 It will lead to a lower SF-36 score. 5% (97/1983) L 2 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (OBQ14.110) An 85-year-old man presents with newly-recognized neck pain after an uneventful fall 4 weeks ago in the dementia unit at the nursing home where he resides. He is on apixaban for atrial fibrillation and Dilantin for seizures. Additionally, he has a history of pulmonary lobectomy for small cell lung carcinoma, pulmonary hypertension, and aortic stenosis. There are no neurologic deficits noted on examination but he does have clear discomfort with neck motion. Current imaging is shown in Figures A-C. What is the best next step in treatment? QID: 5520 FIGURES: A B C Type & Select Correct Answer 1 Observation 8% (126/1526) 2 Halo vest immobilization 4% (57/1526) 3 Anterior osteosynthesis 9% (134/1526) 4 Posterior cervical arthrodesis 16% (248/1526) 5 Cervical collar 62% (940/1526) L 3 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ12.65) A 45-year old male is involved in a motor vehicle accident and presents to the emergency room with complaints of neck pain. Physical exam shows he is an ASIA E. An open-mouth cervical radiograph is shown in Figure A. A sagittal CT scan is shown in Figure B. A CT axial angiogram is shown in Figure C. Which of the following treatment options is contraindicated in this patient? QID: 4425 FIGURES: A B C Type & Select Correct Answer 1 Anterior screw osteosynthesis with single cannulated screw 12% (596/5142) 2 Halo immobilization 15% (790/5142) 3 Anterior screw osteosynthesis with two cannulated screws 10% (499/5142) 4 C1-C2 transarticular screws 50% (2553/5142) 5 Posterior C1-C2 wiring with autograft 13% (656/5142) L 4 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (SBQ12SP.12) An 72-year-old man falls down the stairs and strikes his forehead. He presents to the emergency room with neck pain and a normal neurological exam. He is an active smoker. His past medical history includes chronic obstructive pulmonary disease, atrial fibrillation, and insulin-dependent diabetes mellitus. Coronal and sagittal images from a CT scan of his cervical spine are shown in Figure A. Which treatment option is most appropriate? QID: 3710 FIGURES: A B C D E F Type & Select Correct Answer 1 Figure B 8% (386/4689) 2 Figure C 10% (455/4689) 3 Figure D 3% (140/4689) 4 Figure E 67% (3158/4689) 5 Figure F 11% (523/4689) L 4 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ12.103) A young boy is involved in a motor vehicle accident and presents with neck pain. A CT scan is performed and is negative for fractures. Based on the presence of the ossification center shown in Figure A, what is the most likely age bracket of this patient. QID: 4463 FIGURES: A Type & Select Correct Answer 1 < 1 years of age 0% (15/3763) 2 1-3 years of age 7% (270/3763) 3 3-6 years of age 33% (1227/3763) 4 8-10 years of age 50% (1889/3763) 5 > 12 years of age 9% (336/3763) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ12.116) A 67-year-old male smoker was involved in a motor vehicle accident and presents with neck pain. On initial presentation his neurologic exam was intact. Injury films are shown in Figure A and B. The patient was evaluated and surgical treatment was recommended. The patient left the hospital against medical advice. Seven months later he returns with continued neck pain. His current neurologic exam shows no deficits. A current CT scan and MRI is performed and shown in Figure C and D. What is the most appropriate treatment at this time? QID: 4476 FIGURES: A B C D Type & Select Correct Answer 1 Physical therapy and NSAIDS 15% (698/4742) 2 Hard Cervical Orthosis 3% (140/4742) 3 Halo Immobilization 2% (76/4742) 4 Anterior screw osteosynthesis 7% (353/4742) 5 Posterior C1-C2 fusion 72% (3434/4742) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ11.263) In Figures A-E, which of the following fracture patterns is at greatest risk for nonunion with nonoperative treatment? QID: 3686 FIGURES: A B C D E Type & Select Correct Answer 1 Figure A 2% (61/3616) 2 Figure B 54% (1962/3616) 3 Figure C 3% (102/3616) 4 Figure D 19% (678/3616) 5 Figure E 22% (792/3616) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ10.130) In patients who are neurologically intact, all of the following cervical spine injuries can be appropriately managed with external immobilization in a rigid cervical orthosis EXCEPT QID: 3223 FIGURES: A B C D E Type & Select Correct Answer 1 Figure A 1% (28/4182) 2 Figure B 1% (58/4182) 3 Figure C 5% (209/4182) 4 Figure D 4% (175/4182) 5 Figure E 88% (3698/4182) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (OBQ10.185) In elderly patients with type II odontoid fractures, which of the following treatment modalities has the highest morbidity and mortality? QID: 3278 Type & Select Correct Answer 1 Hard cervical collar 2% (60/2837) 2 Anterior screw osteosynthesis 7% (191/2837) 3 Halo vest immobilzation 80% (2263/2837) 4 Posterior cervical stabilization 4% (121/2837) 5 Soft cervical orthosis 7% (187/2837) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (SBQ09SP.26) A 42-year-old diabetic male smoker presents with neck pain and several contusions on his left side after crashing his motorcycle 2 hours prior. He was helmeted at the time of the accident. He currently denies any pain or weakness. On examination of his spine, there is pain with limited motion of his neck. The motor examination does not reveal any upper or lower extremity weakness and there are no sensory deficits. The patient is placed in a rigid C-collar and undergoes imaging. Figure A is the current CT scan. The patient is eventually cleared for surgery and undergoes the treatment depicted in Figure B two days later. What is associated with this treatment? QID: 3389 FIGURES: A B Type & Select Correct Answer 1 Greater loss of motion compared to posterior fixation 4% (58/1488) 2 Increased rate of infection compared to posterior fixation 10% (154/1488) 3 Acceptable reduction regardless of fracture morphology 6% (92/1488) 4 High likelihood of successful fracture union with few treatment complications 58% (864/1488) 5 Increased risk of nonunion due to 48-hour delay to fixation 20% (301/1488) L 4 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (SBQ09SN.26.2) A 65-year-old diabetic male with a 30-pack-year smoking history and COPD presents to the ED with severe axial neck pain after a fall from standing while attempting to use the restroom in the middle of the night. He is neurologically intact and denies any radicular symptoms. Figures A through D are the current radiographs and CT scans. What is the most appropriate management at this time? QID: 214189 FIGURES: A B C D Type & Select Correct Answer 1 Continued immobilization in a semi-rigid cervical orthosis for 6 to 8 weeks 8% (139/1779) 2 Reduction and posterior instrumented C1-C2 fusion 58% (1031/1779) 3 Open reduction and internal fixation of the odontoid process with an anterior odontoid screw 32% (563/1779) 4 Resection of the odontoid process through a transoral approach 1% (12/1779) 5 Reduction with Gardner-Wells tong traction and 6 weeks of skeletal traction 1% (21/1779) L 4 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ08.78) A 37-year-old male was involved in a motorcycle accident. He is neurologically intact. A coronal and sagittal CT scan is shown in Figure A. What is the most appropriate management? QID: 464 FIGURES: A Type & Select Correct Answer 1 Posterior C1-C2 fusion 5% (182/3344) 2 Anterior odontoid screw fixation 20% (663/3344) 3 Transoral anterior odontoid resection 0% (8/3344) 4 Cervical immobilization for 6-8 week in an external orthosis 72% (2424/3344) 5 Treatment in a soft cervical orthosis for two weeks followed by range of motion exercises 2% (57/3344) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ06.263) A 36-year-old male falls while intoxicated two weeks ago and has had persistent neck pain ever since. For unclear reasons he did not seek medical attention. He now reports persistent neck pain, but denies symptoms in his upper and lower extremities. On physical exam he has Grade 5 motor strength in his upper and lower extremities, normal reflexes, and his sensory exam is normal. A CT scan is shown in Figure A. All of the following place this patient at an increased risk of nonunion EXCEPT: QID: 274 FIGURES: A Type & Select Correct Answer 1 Fracture gap of 2 mm 3% (110/3731) 2 Posterior displacement of > 5mm 2% (79/3731) 3 Delay in treatment of 2 weeks 4% (135/3731) 4 Age < 40 years 89% (3318/3731) 5 Posterior angulation 2% (76/3731) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic
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