Cranial Vertebral Junction Anatomy and Pathology

Transcription

1 Cranial Vertebral Junction Anatomy and Pathology October 2016 Mary Scanlon MD FACR

2 Goals and Objective Goal-Understand CVJ anatomy & pathology Objective-After attending this lecture you will be able to apply key concepts learned and correctly diagnose.. Basilar Invagination Basilar Impression Cranial Settling

3 Cranial Vertebral Junction Consists of: Occiput Atlas (C1) Axis(C2) Articulations and ligaments Encloses : Cervicomedullary junction (CMJ) Cranial Nerves IX-XII

4 Landmarks for CVJ Craniometry 1. Nasion 2. Tuberculum sella Basion 4. Opisthion 5. Hard Palate 6. Ant Arch C Post Arch C1 8. Dens

5 Landmarks for CVJ Craniometry 1. Nasion 2. Tuberculum sella Basion 4. Opisthion Hard Palate 6. Ant Arch C1 7. Post Arch C Dens

6 Landmarks for CVJ Craniometry Jugular Tubercles 2. Occipital Condyles 3. Lat mass C1 4. Dens

7 Lines for CVJ Craniometry 1.Chamberlains Line 2. Mc Gregors Line 3. Wackenheim s Clivus Baseline 4. Clivus-canal angle 5.Welchers s Basal Angle 6.Atlanto-Occipital Axis Angle 7. Redlund-Johnell Line

8 Chamberlains Line Posterior margin hard palate to opisthion Normal=Tip of dens no more 5mm above Ant arch C1/dens usually at or below

9 Wackenheims Line Line down clivus to c spine Normal :Tangent to or intersect posterior 1/3 dens

10 Clivus Canal Angle Normal Min 150 flexion Max 180 extension Abnormal < 150 (too acute)

11 Weshlers Basal Angle Nasion-Tuberculum-Basion Average=132; Normal <140 If>140= Platybasia

12 Atlanto Occiptial Axis Angle (AOAA) Ave 125 Normal <150 Abnormal too flat=condlyar hypoplasia

13 Redlund-Johnell Line Distance from mid C2 base to McGregors line Dx Cranial Settling Abnormal men < 34 mm women < 29 mm

14 CVJ Pathology Terminology 1. Platybasia 2. Basilar Invagination 3. Basilar Impression 4. Cranial Settling

15 Platybasia Flattening of the skull In isolation or with Basilar invagination Basal Angle >140

16 Basilar Invagination Developmental not acquired Congenital abnormalities of the occiput short clivus condylar hypoplasia segmentation anomalies

17 Basilar Invagination Short Clivus- Clivus Canal Angle too acute BI-Short Clivus- AC1 Normal

18 Basilar Invagination Atlanto-occipital segmentation/assimilation most common CVJ anomaly occiput with ant /post arch, lateral masses C1-2 instability 50% C2-3 nonseg 70% Complete fusion anterior arch with occiput Comma shaped configuration

19 Basilar Invagination Condylar Hypoplasia (AOAA to flat) plus segmentation anomaly (lateral masses) BI secondary to condylar hypoplasia and fusion Normal

20 Basilar Impression and Chiari I CVJ Anomalies (33-50%) Hydromyelia (50-75%)

21 Basilar Impression Acquired not congenital bone softening Pagets OI Hypepararthyroidism Rickets Osteomalacia

22 Syndromes associated with CVJ Pathology Klippel-Feil Down Syndrome Achondroplasia Mucopolysaccharidoses Morquio (type IV) and Hurler (type I) varieties Osteogenesis Imperfecta

23 Basilar Impression Osteogenesis Imperfecta Darth Vader or tam-o-shanter

24 Klippel-Feil Triad=short neck, low hairline, limited mobility Cervical segmentation anomalies plus multiple visceral & other congenital anomalies (Sprengels, scoliosis, VSD,GU, eye, ear)

25 Klippel-Feil Three Types Type 2 most common=segmentation 1 or 2 pairs of c bodies ( C2-3 &C5-6)

26 Cranial Settling Dens upward migration Key- Dens moves up-c1 stays put! Redlund-Johnell Line Rheumatoid Arthritis

27 Axis Anomaly Os odontoideum Etiology debated, prob acquired : trauma 1-4 years of age Independent osseous structure superior to body C2 Anterior arch hypertrophic /round Antlanto-axial subluxation! Distinguish from unfused type 2 dens fx Associated with Downs, Morquio, Klippel-Feil, Spondyloepiphyseal dysplasias, Laron syndrome

28 Os odontoideum

29 Os odontoideum versus Chronic Type 2 Dens Fx Chronic Type 2 Normal ½ moon cresentric ant CI Chronic Type 2 Dens Fx Congenital Os Odontoideum

30 Third Occipital Condyle

31 Calcium Pyrophoshate Deposition Disease (CPPD) Large calcified (distinguishes from RA) retro/peridontoid mass +/-subchondral cysts, erosions, AAS

32 CPPD

33 Not everything is CPPD Degenerative Basis Renal spondyloarthropathy

34 CVJ Signs and Symptoms Motor myelopathy-even just lack of endurance Sensory-posterior column,hypalgesia, bladder Brain stem dysfunction-nystagmus,ataxia ENT SNHL loss, vertigo, tinnitus Decreased gag Soft palate paralysis Tongue atrophy Horners Sleep apnea Hemi facial spasm

35 Goals and Objective Goal-Understand CVJ anatomy & pathology Objective-After attending this lecture you will be able to apply key concepts learned and correctly diagnose.. Basilar Invagination Basilar Impression Cranial Settling

36