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cranio-vertebralanomalies-overview-copy-151214131323 (1).pptx

  2. ANATOMY OF CVJ (ARTICULAR) Occiput & atlas ⚫ Upper surfaces of C1 lateral masses is cup-like or concavewhich fit into the ball & socketconfiguration with occipital condyle.( flexion 10*, extension 25*). Atlas & axis – 4 synovial joints ⚫2 median –front & back of dens (Pivotvariety) ⚫2 lateral –b/w opposing articular facets (Planevariety) ⚫Each joint has itsowncapsule & synovial cavity. ⚫Rotation is upto 90* & approx ½ occursat the A-A joint.
  3. ANATOMY OF CVJ(LIGAMENTOUS) Principal stabilizing ligaments of C1 - ⚫-Transverse atlantal ligament ⚫-Alar ligaments Secondary stabilizing ligaments of CVJ are moreelastic & weaker than the primary ligaments. ⚫-Apical ligament ⚫-Anterior & posteriorA-O membranes ⚫-Tectorial membrane ⚫-Ligamentum flavum ⚫-Capsular ligaments
  4. NEURAL Structures related are – ⚫Caudal brainstem (Medulla) ⚫Fourth ventricle ⚫Rostral partof spinal cord ⚫Lower cranial (9,10,11 ,12) & uppercervical nerves (C1,C2, and C3 nerveswith both rami). ⚫In cerebellum, only the tonsils, biventral lobules & the lower partof thevermis (nodule, uvula & pyramid)
  5. Classification of CV Anomalies I. Bony Anomalies A. MajorAnomalies 1. Platybasia 2.Occipitalizationof atlas 3. Basilar Invagination 4. Dens Dysplasia 5.Atlanto- axial dislocation B. MinorAnomalies 1. Dysplasiaof Atlas 2. Dysplasia of occipital condyles, clivus, etc. I. Soft Tissue anomalies 1. Arnold-Chiari Malformation 2. Syringomyelia/ Syringobulbia
  6. Classification of CV Anomalies Congenital- ⚫Malformationof occipital sclerotomes Clivus segmentationanomalies Condylar hypoplasia Assimilationof atlas ⚫ Malformationof atlas Assimilation of atlas Atlantoaxial fusion. Aplasiaof atlas arches. ⚫Malformationof axis. Irregular Atlantoaxial segmentations. Dens dysplasia ⚫Segmentations failureof c2-c3
  7. Developmental and acquired ⚫At foraman magnum- stenosis ⚫Sec.basilar invagination- OI, Pagets ds, osteomalacia, rickets, RA. ⚫Atlantoaxial instability 1. down syndrome 2. Ehlers danlos syndrome 3. MPS 4. Trauma 5. Infection –TB 6. Tumors- Mets, chordom,osteoblastoma, NF ⚫Spontaneous rotatorysubluxation- Grisel syndrome
  8. Clinical features A. Cervical symptomsand signs- pain suboccipital region radiating vertex, stiffness in 85% B. Myelopathic Features- long tract involvement and wasting C. CN involvement- IX, X,XI,XI in 20% D. Vascular - in 15% Transient Attack of V-B insufficiency E. Sensory symptomof post. column involvement. F. Cerebellar symptoms/signs- Nystagmus, Ataxia, intention tremor, dysarthria G. Featuresof Raised ICT- usually seen in Pateints Having basilar impresssionand/orACM
  9. INVESTIGATIONS ⚫ X Rays -Antero-posteriorview -Lateral view -Open mouth view fordens ⚫ Stress X-Rays (neutral, flexion, extention) ⚫ CT Scan and 3D reconstruction ⚫ MRI conventional and dynamic ⚫ Myelogram & Ventriculogram ⚫ Angiography
  10. CRANIOMETRY: ⚫Craniometryof the CVJ uses a series of lines, planes & angles todefine the normal anatomic relationshipsof the CVJ. ⚫These measurementscan be taken on plain X rays,3D CT or on MRI. ⚫No single measurement is helpful. ⚫disadvantage --anatomicstructuresand planesvarywithin a normal range.
  11. Lines and angles used in radiologic diagnosis of C.V anomalies. Parameter Normal range limits A. PLATYBASIA B. BASILAR INVAGINATION C. ATLANTO-AXIAL DISLOCATION * • Basal angle • Boogard’s angle • Bull’s angle < 150 degree < 136 degree < 13 degree < onethird of odontoidabove this line < 5 mm odontoid lies below this > 35 mm > 22mm. • Chamberlain’s line • Mcgregor’s line • Mcrae line • Klausheightindex • Atlanto-temporo mandibular index • Atlanto-odontoid space upto 3 mm inadults upto 5 mm inchildren
  12. Chamberlain’s line ⚫ From tipof hard palate toposterior tipof Foramen Magnum (opisthion). ⚫ It helps to recognise basilar invaginationwhich is said to be present if the tipof thedens is >3 mm abovethis line
  13. Mc Gregor’s line (basal line) ⚫ Line drawn from posterior tip of Hard palate to lowest partof Occiput ⚫ Odontoid tip >5mm above = Basilar Invagination ⚫ Position changed with flexion and extension so not used. ⚫ Should be used when lowest part of occipital bone is not Foramen Magnum.
  14. Wackenheim’s clivus canal line ⚫ Linedrawnalong clivus into cervical spinal canal ⚫ Odontoid is ventral and tangential tothis line ⚫ If not –suggestAAD or BI
  15. Mc rae’s line ( foramen magnum line) ⚫ Joinsanteriorand posterioredges of Foramen magnum ⚫Tipof odontoid is below this line. ⚫When sagittal diameterof canal <20mm, in patientof >8 yrof age neurological symptoms occur – Foramen Magnum Stenosis
  16. Welcher’s Basal Angle ⚫Nasion to tuberculum sella ⚫Tuberculum sellae to the basion along planeof theclivus ⚫Normal – 1240 - 142 ⚫> 1400 = platybasia ⚫< 1300 is seen in achondroplasia
  17. Bulls angle ⚫Line representing prolongation of hard palateand line joining the midpointsof theant & post arches of C1. ⚫Normal : <100 ⚫Basilar invagination - >130
  18. Boogard ‘s Angle ⚫1s t line between Dorsum sellae to Basion & Mc Rae’s line. ⚫Average - 1220 ⚫> 1350 ⚫Basillar impression
  19. Atlantooccipital joint Axis Angle (Schmidt – Fischer angle) ⚫Range between 124- 127. ⚫Wider in occipital condyle hypoplasia. O C2 AA JT AO JT C1 C1
  20. FISHGOLD’S DIGASTRIC LINE( Biventerline) Connects the digastric grooves ( fossae for digastric muscleson undersurface of skull just medial to mastoid process)  Tipof theodontoid process and atlanto-occipital joint normally project 11 mm and 12 mm below this line respectively.  Basilar invagination is presentwhen atlanto-occipital joint projects at orabove this line.
  21. FISHGOLD’S BIMASTOID LINE ⚫Lineconnecting tipof mastoid process. ⚫Odontoid process should be less than 10 mm above this line- BI
  22. HEIGHT INDEX OF KLAUS ⚫Distance between tipof dens and tuberculum cruciate line( line drawn from tuberculum sella to internal occipital protruberence) ⚫40-41mm normal ⚫In basilar invagination <30 mm
  23. 1.nasion 2.tuberculum sella 3.basion (anterior margin of the foramen magnum) 4.opisthion (posterior margin of the foramen magnum) 5.posteriorpole of the hard palate 6.anteriorarchof theatlas 7. posteriorarchof theatlas 8. odontoid process
  24. Platybasia ⚫Refersonly toan abnormallyobtuse basal angle, may be asymptomatic, and is not a measure of basilar invagination. ⚫>140 basal angle.
  25. Occipitalization of atlas/assimilation ⚫50% of all cvj anomaly in india. ⚫Failureof segmentation btw last occipital and first spinal sclerotome. ⚫ Gradual orsudden onset by trauma ⚫No movement btw OA –leads increases stress at AA joint –get instability ⚫Associated –with basilar invagination, occipital vertebra, KF syndrome
  26. fusionof the lateral Coronal polytomogramdemonstratescomplete C-i masses (1) totheoccipital condyles (0).
  27. ⚫ Incidence - 1.4 to 2.5 per 1000 children. Itaffects both sexes equally. ⚫ Neurological symptoms usuallyoccur in third and fourth decades and vary depending on the area of spinal cord impingement. ⚫ Clinical Findings ⚫ Low hairlines ⚫ Torticollis ⚫ Short necks ⚫ Restricted neck movement. ⚫ Dull, aching pain in the posteriorocciput and the neck ⚫ Episodic neck stiffness
  28. TOPOGRAPHIC FORMS (WACKENHEIM): ⚫Type I: Occipitalization (subtotal) with BI. ⚫Type II: Occipitalization(subtotal) with BI & fusion of 2nd & 3rd cervical vertebrae. ⚫Type III: occipitalization (Total orsubtotal) with BI & maldevelopment of the transverse ligament. may be associated with various malformations like C2-C3 fusion, hemivertebra, dens aplasia, tertiarycondyle, etc ⚫Symptomsaredue to-absence of a freeatlas- TL fails to develop which causes posterior displacement of axis & compression of the spinal cord
  29. BASILAR INVAGINATION ⚫Basilar invagination implies that the floor of the skull is indented by the upper cervical spine, & hence the tip of odontoidis more cephalad protruding into the FM. ⚫Two types : primary invagination, which is developmental and more common, and secondary invagination, which is acquired. ⚫Primary invagination can be associated with occipito atlantal fusion, hypoplasia of the atlas, a bifid posterior arch of the atlas, odontoid anomalies.
  30. SECONDARY BASILAR INVAGINATION 1. Hyperparathyroidism 2. Hurler's syndrome 3. Rickets/OM/Scurvy 4. Hajdu-Cheney Syndrome. 5. Paget's disease. 6. Cleidocranial dysostosis 7. Osteogenesis Imperfecta
  31. ⚫BI isassociated with high incidence of vertebral artery anomalies. Topographic typesof BI : ⚫Anterior BI : hypoplasiaof the basilarprocess of the occipital bone. ⚫BI of theoccipital condyles (Paramedian BI)–Condylar hypoplasia ⚫BI in the lateral condylararea. ⚫Posterior BI: posterior margin of the FM is invaginated. ⚫Unilateral BI. ⚫Generalised BI
  32. SIGNS / SYMPTOMS Usuallyoccur in 2nd or 3rd decade. ⚫ Short neck(78%),torticollis (68%) ⚫ Associated ACM & syringomyelia(25 to 35%). ⚫ Motor & sensorydisturbances (85%). ⚫ Lowercranial nerves involvement ⚫ Headache & pain in the napeof neck (greateroccipital N) ⚫ Raised ICP due to posteriorencroachmentwhich causes blockageof aqueductof sylvius. ⚫ Compression of cerebellum & vestibularapparatus leading to vertical or lateral nystagmus(65%) . ⚫ Vertebral artery insufficiencys/s.
  33. Atlantoaxial Instability ⚫Atlantoaxial instability (AAI) is characterized byexcessive movement at the junction between the atlas (C1) and axis (C2) as a result of eithera bony or ligamentous abnormality. ⚫Neurologic symptomscan occurwhen the spinal cord or adjacent nerve roots are involved. Incidence of AAD – ⚫57% of all CVJ anomalies. ⚫8.3% of all causesof cervical compression
  34. ⚫GREENBERG’S CLASSIFICATION : Incompetence of theodontoid process – Congenital Traumatic -# of odontoid Infections Tumor –1o/ 2o Adults (RA & Incompetence of theTAL – Congenital Traumatic Inflammatory –Children (pharynx nasopharynx) ankylosing spondylitis)
  35. WADIA CLASSIFICATION : ⚫Group I: AAD with occipitalizationof atlas & fusion of C2 & C3. ⚫Group II: odontoid incompetence due to its maldevelopment with no occipitalizationof atlas. ⚫Group III: odontoid dislocation but no maldevelopment of dens oroccipitalizationof atlas.
  36. Non-traumatic conditions associated with increase in theatlantoaxial distance: ⚫Down syndrome -Due to laxityof the transverse ligament ⚫Grisel syndrome –Atlantoaxial subluxation associated with inflammation of adjacent soft tissues of the neck ⚫Rheumatoid arthritis-From laxityof the ligamentsand destruction of thearticularcartilage ⚫Osteogenesis imperfecta ⚫Neurofibromatosis ⚫Morquiosyndrome -Secondary toodontoid hypoplasiaor aplasia ⚫Other arthridities (Psoriasis, Lupus)
  37. Anterior Atlanto-Dental Interval (AADI) ⚫ AAS is + when >3 mm in adults & >5mm in children ⚫ Measured from posteroinferior margin of antarch of C1 to theant surfaceof odontoid ⚫ AADI 3-6 mm  trans lig. damage ⚫ AADI >6mm  alar lig. damagealso
  38. PosteriorAtlanto-Dental Interval (PADI) : ⚫ Distance b/w posterior surface of odontoid & anterior marginof post ring of C1 ⚫ Considered better method as it directly measures the spinal canal ⚫ Normal : 17-29 mm at C1 ⚫ PADI <14mm : predicts cord compression
  39. RISK FACTORS FOR CORD COMPRESSION IN AAS- ⚫AADI > 9 mm ⚫PADI < 14 mm ⚫Basilar Invagination, especially if associated with AAS of anydegree
  41. Fielding and Hawkinsclassification: ⚫Type I- is simple rotatorydisplacement with an intact transverse ligament. ⚫Type II- injuries involve anteriordisplacement of C1 on C2 of 3-5 mm with one lateral mass serving as a pivot point and adeficiency of the transverse ligament. ⚫Type III -injuries involve greater than 5 mm of anterior displacement. ⚫Type IV-injuries involve the posteriordisplacement of C1 on C2. ⚫Both Type III and IV are highly unstable injuries.
  42. TREATMENT- ⚫Type I injuries (stablesubluxations) –Collar. ⚫Type II injuries may be potentiallyunstable. ⚫Type III and IV rotatorydisplacements thatare unstableare treated surgicallywith a reduction and C1- 2 fusion. ⚫Techniques of fusion vary from sublaminar wiring techniques like Brooks or Gallie, Halifax clamp, or transarticularscrew of Magerl.
  43. DENS DYSPLASIA ⚫Type 1 (Os odontoideum) separateodontoid process ⚫ Type 2 (Ossiculum terminale) failure of fusion of apical segmentwith its base ⚫Type 3 – Agenesis of odontoid base & apical segment lies separately. ⚫Type 4 – Agenesis of odontoid apical segment ⚫Type 5 –Total agenesis of odontoid process.
  44. OS ODONTOIDEUM ⚫At birth odontoid base is separate from the body of axis by a cartilage which persists until the ageof 8, later -ossified,or may remain separate as Os- odontoidium. ⚫Independent osseous structure lying cephalad to theaxis body in the location of the odontoid process. ⚫Anterior arch of the atlas is rounded and hypertrophic but the posteriorarch is hypoplastic. ⚫Cruciate ligament incompetence and A-A instabilityare common
  45. Persistent ossiculum terminale: Bergman ossicle ⚫Failureof fusion of the terminal ossicle to the remainderof theodontoid- normally by 12 yearsof age. ⚫Confused with a type 1 odontoid fracture. ⚫Stable when isolated and of relatively little clinical significance. ⚫Odontoid process is usually normal in height.
  46. Condylar Hypoplasia: ⚫ Occipital condyles are underdeveloped and havea flattened -- and widening of the AO jointaxis angle -- leading to BI. ⚫ Lateral masses of the atlas may be fused to the hypoplastic condyles, further accentuating the BI. ⚫ Limits movementsat the A-O joint. ⚫ Violationof the Chamberlain line and widening of atlantooccipital joint axis angle
  47. Basiocciput Hypoplasia: ⚫Hypoplasiaof the basiocciput may be mild or severe, depending on the numberof occipital sclerotomes affected. ⚫Lead-basilar invagination. ⚫Clivus-canal angle is typically decreased
  48. Posterior Arch Anomalies ⚫ Posteriorrachischisis > aplasias and hypoplasia ⚫ Total orpartial aplasiaof the posterioratlasarch. ⚫ Isolated, is usuallyasymptomatic, but may beassociated with anteriorAA subluxation. ⚫ Simulating Jefferson fracture.
  49. SPLIT ATLAS ⚫Anterior +posteriorarch rachischisisis =“splitatlas”. ⚫Usuallyasymptomatic butwideclefts with only a fibrouscovering may lead toatlas instability
  50. Klippel- Feil Syndrome Triad ⚫ Decreased rangeof motion in the cervical spine m/c ⚫ Short, webbed neck ⚫ Low hairline. Type 1- Massive fusionof cervical and upper thoracicvertebra 2 –Fusion of 2 cervical vertebra ,hemivertebra, scoliosis, OA fusion 3 Lower thoracicand upper lumber spineanomaly. 4 Sacral agenesis
  51. ASSOCIATED CONDITIONS: ⚫Scoliosis- 60%. ⚫Genito-urinary- 65%. m/c is absence of kidney. ⚫Sprengel's deformity- 35% ⚫Cardio-pulmonary-5-15%, m/c V.S.D. ⚫Deafness-30%, all types, MC mixed. ⚫Sykinesis-Mirror motions 20%. ⚫Cranio-cervical abnormalities- (25%)- Includes C1-C2 hypermobilityand instability, BI, Chiari I malformation, diastematomyelia, & syringomyelia.
  52. ⚫20% of patients mayshow facial asymmetry, torticollis and neck webbing (pterygiumcolli). ⚫Ptosis of theeye, Duane'seye contracture, lateral rectus palsy, facial nerve palsyand cleft palate. ⚫Upperextremityabnormalities, ie. syndactyly, hypoplastic thumb, supernumarydigitsand hypoplasiaof the upper extremity. SYMPTOMS: ⚫Due to the hypermobilityoccurring at theopen segments, can lead toeither frank instabilityorosteoarthritis. ⚫Mechanical symptomsdue to joint irritation. ⚫Neurologic symptomsdue to root irritation or spinal cord compression
  53. Arnold-Chiari Malformation ⚫Type 1- m/c -caudal displacement of peglikecerebellar tonsils below the level of the foramen magnum, -congenital tonsillar herniation, tonsillar ectopia, or tonsillar descent. Syringomyelia in 50 to 70%. ⚫Type II -less common and more severe, almost invariably associated with myelomeningocele. Symptomatic in infancy orearlychildhood. -caudal displacement of lower brainstem (vermis, medulla, pons, 4th ventricle) through the foramen magnum. ⚫Type III -herniation of cerebellum intoa high cervical myelomeningocele. ⚫Type IV -cerebellar agenesis. type III and IV -exceedingly rareand incompatible with life .
  54. ⚫ Chiari type I malformation. ⚫ (white line) down to the level of C1 posterior arch.
  55. TREATMENT: ⚫No role forprophylactic treatment in an asymptomatic patientwith an incidental CMI. ⚫All symptomatic patients requiresurgical treatment. ⚫In patients with CMI and hydrocephalus, the primary treatment must be shunting theventricularsystem. ⚫In presenceof symptomaticventral compression from BI or retroflexion of the odontoid, the treatment is ventral decompression. ⚫In patients with a CMI,syrinx with scoliosis, the initial treatment is posteriorcervicomedullary decompression.
  56. OUTCOMES: ⚫Patients presenting with pain (mainly headache and neck pain) & weakness withoutassociated atrophy –best results. ⚫Cranial nervedysfunction –moderate recovery ⚫Sensory recovery poor. ⚫Presence of central cord syndrome due toa syrinx- indicativeof poor recovery . ⚫Three factors most prognostic of pooroutcome are atrophy, ataxia, and scoliosis. ⚫Brain stem and cerebellar syndromes -good recovery
  57. TUBERCULOUS AAD ⚫<1% of all cases of spinal TB. ⚫Local pain, restriction of neck movements & acute tenderness of upper C-spine –Cardinal features. ⚫Compressionof CMJ could bedue togranulation tissue, cold abscess or bony instability & displacement. ⚫Waxing & waning picture . ⚫Ligaments areextensively infiltrated . ⚫Hyperaemicdecalcification occurs.
  58. Radiological findings in 3 stages– ⚫Stage I: Retropharyngeal abscess with ligamentous laxity +, bonyarchitecture of C1-C2 preserved. ⚫Stage II: Ligamentous disruptionwith AAD, minimal bone destruction & retropharyngeal mass + ⚫Stage III: marked destruction of bone, complete obliteration of anteriorarch of C1 & complete loss of odontoid process, marked AAD & O-A instability.
  59. TREATMENT: ⚫ Bed rest, cervical traction, evacuation of retropharyngeal abscess & prolonged external immobilizationalong with ATT. Indicationsof Surgery : ⚫ Gross bonydestruction with instability ⚫ Major neurological deficits ⚫ Unstablespine following conservativeTx Surgery : ⚫ Posteriorfusion ⚫ Anteriordecompression with orwithout fusion
  60. RHEUMATOID ARTHRITIS & CVJ ⚫20% of RA have AAD. ⚫Osteophyte formation (stabilizing effect) does not occur secondary todeficient osteogenesis(characteristic of RA). ⚫Loss of tensile strength & stretching of TL due to destructive inflammatorychanges as well as secondary degenerativechanges in tissues from vasculitis--AAD. ⚫Granulation tissue in thesynovial joints. ⚫Odontoid process –osteoporosis, angulation/#.
  61. REFFERENCES- ⚫ Textbook of contemporary neurosurgery vol 1 By Vincent A Thamburaj ⚫ Apley’s Textbook of Orthopaedics ⚫ A Textbook of Neuroanatomy GARTNER and Rhoton ⚫ Youmanstextbook of neurosurgury ⚫ Texbook of neurosurgery –rengacharyand shetty. ⚫ Managementof Congenital Atlanto-Axial Dislocation Neurology India, Vol. 50, No. 4, Dec, 2002, pp. 386-397 Review Article ⚫ ⚫