1 Page 1 Transorbital endoscopic amygdalohippocampectomy 26 April, 2015 Tim Lucas, MD, PhD Neurosurgery [email protected]2 Financial Disclosures None Lucas Lab Funding sources T32 3 TEA 4 (Cranial) (Cranial) Range of globe displacement: 4-7 mm (4 cadaver approaches) Lucas, et al., in preparation 5 (Cranial) (Cranial) 6 Distance from lateral orbital rim to lateral aspect of dural exposure Range 2.2-2.8 cm (over 4 cadaver approaches)
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TEAe003ca8d94addb66aab5-c5d5615aae30db61d1ced35d35f0936c.r32.… · Variants at the Craniovertebral Junction Jason Talbott, MD, PhD Assistant Professor in Neuroradiology San Francisco
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Smoker et al. Childs Nerv Syst (2008), 24:1123-1145
RINGS
Malformations of Surrounding Rings
Lateral component and hypochordal bow of proatlas (C0) and C1 resegmented sclerotomes
PROATLAS (C0) C1 SCLEROTOME
Atlas assimilation Hypoplastic anterior C1 arch
Occipital condyle hypoplasia
Hypoplastic/aplastic C1 posterior arch
Hypertrophic occipital condyle
Aplasia lateral mass C1
3rd Occipital condyle
Bifid anterior and posterior C1 arch
Assimilation of atlas:
• MC anomaly of CVJ (0.1-3% population)
• Anterior, lateral, posterior zones
• C1-C2 instability• Associated with…
• Basilar invagination• Klippel-Feil• Chiari I
UCSF Teaching File
RINGS
Occipital condyle hypoplasia:
RINGS
Smoker et al. Childs Nerv Syst (2008), 24:1123-1145
Occiptal condyle hyperplasia:
RINGS
Pang et al. Childs Nerv Syst (2011), 27:253-64
Malformations of Surrounding Rings
Lateral component and hypocordal bow of proatlas (C0) and C1 resegmented sclerotomes
PROATLAS (C0) C1 SCLEROTOME
Atlas assimilation Hypoplastic anterior C1 arch
Hypoplasticoccipital condyle
Hypoplastic/aplastic C1 posterior arch
Hypertrophic occipital condyle
Aplasia lateral mass C1
Bifid anterior and posterior C1 arch
RINGS
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C1 Neural arch hypoplasia:
• Derived from lateral C1 sclerotome
• Partial to complete• Keller type• Usually stable• C1 posterior arch
“rachischisis” common (4% population
RINGS
UCSF Teaching File
Anterior C1 arch hypoplasia:
• Derived from C1 hypchordal bow
• True aplasia very rare
• Varying degrees of C1-C2 instability• Loss of TAL
attachment and dens
RINGS
Pang et al. Childs Nerv Syst (2011), 27:253-64
SYNDROMES
Syndromes associated with CVJ anomolies:
• Down syndrome• Klippel Fiel• Achondroplasia• Mucopolysaccaridoses• Osteogenesis imperfecta
Smoker et al. Childs Nerv Syst (2008), 24:1123-1145
PILLAR AND RINGS
Malformations of Central Pillar
AXIAL component of occipital sclerotomes, proatlas (C0) and C1 Sclerotomes
ODONTOID BASIOCCIPUT
Odontoid hypoplasia
Basiocciput hypoplasia
Os odontoideum Basilar impression
Ossiculumterminale
Basilar kyphosis
Os avis
Bifid dens
Malformations of Surrounding Rings
LATERAL component and hypochordal bow of proatlas (C0) and C1 re-segmented sclerotomes
PROATLAS (C0) C1 SCLEROTOME
Third occipital condyle
Hypoplastic anterior C1 arch
Hypertrophic occipital condyle
Hypoplastic/aplastic C1 posterior arch
Atlas assimilation Aplasia lateral mass C1
Bifid anterior and posterior C1 arch
Conclusion
• Pillar-ring model of CVJ helps classify and conceptualize vast array of pathologies
• Embryology is your friend• Axial sclerotomes Pillar• Lateral sclerotomes Rings • Proatlas is like “C0”
• CT (thin cut with 3D reformats) for bony anomalies
• MRI for associated compressive pathology
REFERENCES
• Smoker et al. Childs Nerv Syst (2008), 24:1123-1145.
• Pang et al. Childs Nerv Syst (2011), 27:253-64.
• Dudek and Fix, Embryology, 1998.
• Menezes et al. Neurosurg (2009), 64:945-54
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Trauma at the Craniovertebral Junc8on: Don’t Lose Your Head
Lubdha M. Shah ASNR 2015
Objec8ves
• Review anatomy of the craniovertebral junc8on
• Discuss various trauma8c injuries of the CVJ – Consider the associated injuries
• Summarize the complimentary role of different imaging modali8es in assessing CVJ injuries
Harris’ Rule of 12 AOD
• BAI – distance between basion & rostral extension of posterior cor8cal margin of axis
• 3.4 mm (8.7-‐26) • Higher sensi8vity on radiographs vs. CT
Rojas CA, et al. Reassessment of the Craniocervical Junc>on : Normal Values on CT. AJNR 2007
AOD
• BDI – distance from most inferior por8on of basion to superior dens
• 5.7 mm (1.4 -‐9.1)
AOD
• Powers ra8o – ra8o of distance between basion to spinolaminar line of atlas & distance from opisthion to posterior aspect of anterior C1 arch
• BC/OA • 0.8 mm (0.6-‐1.2) • Sensi8vity 33-‐60%
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AOD
• ADI – Predental space – 1.3 mm (0.6-‐2.4 mm) – Maintained by atlantodental, alar and transverse ligaments
AOD
• Atlanto-‐occipital interval
• Congruent through out joint space
• 1.0 mm (0.5-‐1.8)
• AO disloca8on • AO subluxa8on • Hyperextension , lateral flexion, +/-‐ hyperflexion
• Incompetence of alar ligament, tectorial membrane
• Type 1 odontoid fx
Atlanto-‐occipital Dissocia8on Injuries
• 3 types (Traynelis) – Anterior displacement of occiput
– Longitudinal distrac8on with separa8on of occiput from C1
– Posterior displacement of occiput with respect to C1
• Does not address severity of injury
• Rotatory subluxa8on
Atlanto-‐occipital Dissocia8on Injuries
• Incidence higher in peds – Atlanto-‐occipital joint less concave
– Underdeveloped ligaments
• High mortality -‐ brain stem injury
• Injuries of upper cervical nerve roots
• Vasospasm and dissec8on of vertebral or IC arteries
Atlanto-‐occipital Dissocia8on Injuries Diffusion Tensor Imaging • Correla8on with white mader integrity • May offer greater precision in assessing
neurologic deficit over neurologic examina8on alone
ADC dec in SCI pa8ents Hemorrhage greatest decrease, followed by quadriplegia
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Clivus Fracture
• High-‐energy blunt trauma • CN deficits, esp. VI and VII • High mortality: – brainstem trauma – vertebrobasilar occlusion
Occipital Condylar Fracture • Hi energy blunt trauma with
axial compression, lateral bending or rota8onal injury to alar ligament
• Collet-‐Sicard syndrome: paralysis of CN 9,10,11,12
• Type 1 – Axial loading; ipsi alar ligament
may be compromised, but stability maintained by contra alar ligament & tectorial membrane
Occipital Condylar Fracture Type 2 – Extends from occipital bone via condyle to enter FM
– Stability maintained by intact alar ligaments & tectorial membrane
Type 3 Mediated via alar ligament tension Assoc. disrup8on of tectorial membrane & contra. alar ligament may cause instability
Jefferson C1 Fracture • Axial loading injury • Fall from height, diving injury
• Simultaneous disrup8on of anterior & posterior arches of C1 +/-‐ disrup8on of ligaments
Jefferson Fracture • Stable if transverse ligament is intact
• Torn transverse ligament – Combined offset of C1-‐C2 lateral masses >= 6.9 mm
– Widening of atlantoaxial interval >= 6.9 mm
• Widening of ADI with dynamic maneuvers also suggests transverse ligament injury (not appropriate in acute semng)
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Transverse Ligament Injury
Dickman and Sonntag • Type 1 – Midsubstance ligamentous injury
– Surgical treatment • Type 2 – Avulsion of ligamentous inser8on
– Trial of external mobiliza8on, poten8al of osseous helaing
Dickman CA, Sonntag VK. Injuries involving the transverse atlantal ligament: classifica8on and treatment guidelines based upon experience with 39 injuries. Neurosurgery. 1997 Apr;40(4) 886-‐7.
Odontoid Fracture • Hyperflexion mechanism
– 5-‐15% of cervical spine fxs • Anderson & D’Alonzo
Classifica8on – Type 1
• Upper dens • Stable, immobiliza8on
– Type 2 • Base of dens • Most common, non-‐union rate 10-‐77%
– Type 3 • Body of axis, facets
Roy-‐Camille Classifica8on – Poten8al for Dens Displacement
• Type 1: Fx line inclined forwards, anterior dens displacement
• Type 2: Fx line inclined backwards, posterior dens displacement
• Type 3: Horizontal fracture, dens displaced anterior or posterior
Odontoid Fracture • STIR commonly used to evaluate
acuity of fractures
• STIR signal may be decreased or absent in acute dens fractures, par8cularly in elderly
Lensing FD, et al. Reliability of the STIR sequence for acute type II odontoid fractures. AJNR 2014 Aug;35(8):1642-‐6.
Trauma8c Spondylolisthesis
• AKA Hangman’s Fracture • Fracture of C2 pars interar8cularis due to hyperextension and distrac8on
• Dens typically spared • Extension to transverse foramen à vertebral artery injury
– Fixa8on occurs within normal range of rota8on of C1-‐C2 joint
– Flexion with rota8on force • Pediatric pa8ents have
enhanced elas8city of ligaments, horizontally oriented, shallower joint surfaces of lateral masses, incompletely developed neck musculature, larger head-‐body rela8onship
• Adults with RA, Down Syndrome, Morquio Syndrome and Marfan Syndrome
Atlantoaxial Rotatory Subluxa8on • Lateral flexion with
contralateral rota8on “Cock-‐Robin”
• Neural damage, death – Time between injury &
reduc8on directly correlates with prognosis
– Irreducible aser 1-‐3 months, requires surgery
– Tx: trac8on for 6 weeks, analgesics, AA arthrodesis
• CT and MRI before reduc8on to evaluate for addi8onal spine injuries
Atlantoaxial Rotatory Subluxa8on Fielding and Hawkins Classifica8on • Type 1: rotatory subluxa8on, NO displacement of atlas (ADI≤ 3 mm) • Type 2: rotatory subluxa8on with anterior displacement of atlas 3-‐5 mm • Type 3: rotatory subluxa8on with anterior displacement of atlas > 5 mm • Type 4: rotatory subluxa8on with posterior displacement of atlas
Summary
• Review the complex func8onal CVJ anatomy – Key measurements in assessing trauma8c injury
• Outlined important trauma8c CVJ injuries – Iden8fied associated injuries
• Compared different imaging modali8es in assessing CVJ injuries
References • Levine AM, Edwards CC. The management of trauma8c
spondylolisthesis of the axis. J Bone Joint Surg Am. 1985 Feb;67(2):217-‐26.
• Fielding JW, Hawkins RJ. Atlanto-‐axial rotatory fixa8on. (Fixed rotatory subluxa8on of the atlanto-‐axial joint). J Bone Joint Surg Am. 1977 Jan;59(1):37-‐44.
• Prad H, Davies E, King L. Trauma8c injuries of the c1/c2 complex: computed tomographic imaging appearances. Curr Probl Diagn Radiol. 2008 Jan-‐Feb;37(1):26-‐38. Review.
• Roy-‐Camille R, Saillant G, Judet T, et al (1980) [Factors of severity in the fractures of the odontoid process (author's transl)]. Rev Chir Orthop Reparatrice Appar Mot; 66:183–186. French.