Contents Classification of CV Anomalies Anatomical and radiological aspects Specific anomalies – AA dislocation, Dens dysplasia, KFS ACM, Syrinx Clinical features Management
ClassificationI. Bony Anomalies A. Major Anomalies B. Minor Anomalies 1. Platybasia 1.Dysplasia of Atlas 2. Occipitalization 2.Dysplasia of occipital condyles, clivus, etc. 3. Basilar Invagination 4. Dens Dysplasia 5. Atlanto- axial dis. II. Soft Tissue anomalies 1. Arnold-Chiari Malformation 2. Syringomyelia/ Syringobulbia
Anatomical and Radiological Aspects• Anatomical Landmarks • Nasion, Tuberculum Sellae, Clivus, Basion, Opisthion, Indion • Lines , angles and indexes •Basal Angle • Chamberlain’s Line •Boogard’s angle • McGregor’s Line •Bull’s angle • McRae’s Line •A-O interval •EDFM • Klaus Height Index • AT Index
Table : Lines and angles used in radiologic diagnosis of C.V anomalies. Parameter Normal range limitsA. PLATYBASIA • Basal angle < 150 degree • Boogard’s angle < 136 degree • Bull’s angle < 13 degreeB. BASILAR INVAGINATION • Chamberlain’s line < one third of odontoid above this line • Mcgregor’s line < 5 mm • Mcrae line odontoid lies below this • Klaus height index > 35 mm • Atlanto-temporo > 22mm. mandibular indexC. ATLANTO-AXIAL DISLOCATION * • Atlanto-odontoid space upto 3 mm in adults upto 5 mm in children • EDFM > 19mm * May be reducible, partially reducible or irreducible
Atlanto-Axial Dislocation– Traumatic– Spontaneous (Hyperemic)– Congenital Wadia Classification (1973)• Group 1- associated with occipitalization & frequent fusion of C2,C3• Group 2- Associated with Dens Dysplasia- frequently totally reducible• Group 3- No Congenital Bony abnormality
Type 1 : Syringomyelia with obstruction of Foramen Magnum and dilatation of central canal ( Developmental Type)1. With type 1 Chiari malformations2. With other obstructive lesion of foramen magnum Type 2 : Syringomyelia without obstruction of Foramen Magnum ( Idiopathic Developmental Type) Type 3: Syringomyelia with other diseases of spinal cord ( Acquired Types )1. Spinal cord tumors ( usually intramedullary hemangioblastoma)2. Traumatic myelopathy3. Spinal Arachdnoitis and pachymeningitis.4. Secondary myelomalacia from cord compression ( tumour , spondylosis ) , infarction , hematomyelia Type 4 : Pure hydromyelia ( developmental dilatation of the cental canal ) with or without hydocephalus.
Types of dens dysplasia Type 1 (Os odontoideum) separate odontoid process Type 2 (Ossiculum terminale) failure of fusion of . apical segment with 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.
Klippel- Feil Syndrome• Type 1- Massive fusion of cervical and often upper thoracic vertebra. Associated with short neck, low hairline and restricted neck movements• Type 2- associated with fusion of several cervical vertebra• Type 3 – associated with fusion of 2 cervical vertebra.Other associated anomalies:- Sprengel shoulder
Presenting FeaturesA. Cervical symptoms and signsB. Myelopathic Features- long tract involvement and wastingC. CN involvement- IX, X,XI,XII,V, AND rarely VIII,VIID. Cerebellar symptoms/signs- Nystagmus, Ataxia, intention tremor, dysarthriaE. Transient Attack of V-B insufficiencyF. Features of Raised ICT- usually seen in Pts. Having basilar impresssion and/or ACM
Importants Points to remember1. Short neck, low hairline, restricted neck movements are frequently seen in KF anomaly, Occipitalization, and basilar invagination2. Transient Attacks of VB insufficiency are usually encountered in Pts. With A-A dislocation.3. Several bony and soft tissue anomalies often co-exist4. Neurological deficit is usually produced by A-A dislocation, Basilar Invagination, ACM and Syringomyelia / Syringobulbia
Arnold-Chiari Malformation• Type 1- Cerebellomedullary malformation without meningocoele with variable downward displacement of cerebellar tonsils into spinal canal• Type 2. Cerebello-medullary malformation with meningocoele or meningomyelocoele along with variable downward displacement of inferior vermis of cerebellum, brainstem and IVth ventricle into cervical canal
Syringomyelia/ SyringobulbiaProgressive degenerative/ developmental disorder of thespinal cord, characterized clinically by brachialamyotrophy, suspended dissociative sensory loss, andpathologically by cavitation in the central region of thespinal cord. 90% cases associated with ACM type I.Types I: Syrinx with obstn of the foramen magnumType II: Syrinx without obstn of the foramen magnumType III: Syrinx with other diseases of the spinal cordType IV: Pure hydromyeliaSyringobulbia: the lower brainstem equivalent ofsyringomyelia, usually co-exists
Treatment of CV anomalies1. Treatment of A-A dislocation a) Conservative treatment- For patients having only cervical symptoms or transient VB insufficiency with or without mild neurological deficit maybe initially managed conservatively using – 1. Cervical Collar 2. Head- Halter Traction- if there is associated myelopathic features b) Surgical Management
Treatment of Basilar Invagination and ACMA. Conservative managementB. Surgical treatment A. Upper cervical laminectomy and enlargement of Foramen Magnum