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Disc losur e s
De puy Spine
Co nsulting Gra nt suppo rt
Bio me t Spine
Co nsulting Gra nt suppo rt
Neurological Complications in Adult Cervical Spine Surgery - - PowerPoint PPT Presentation
Neurological Complications in Adult Cervical Spine Surgery - - PowerPoint PPT Presentation
Neurological Complications in Adult Cervical Spine Surgery Orthopaedic Summit 2017 Las Vegas Michael W. Groff, MD Director of Spinal Neurosurgery Vice-Chairman Neurosurgery Brigham and Womans Hospital Harvard Medical School Disc losur e
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Anterior Cervical Discectomy
First proposed in the 1950’s Ortho and Neuro contributions Wide indications Significant complications
- Recurrent laryngeal nerve palsy
- Swallowing difficulties
- Hip graft harvest hurts
- Subsidence and pseudoarthrosis
- Adjacent segment disease
- Sagittal balance - kyphosis
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Hip graft harvest hurts
Persistent hip pain reported to independent reviewer in 1/3 patients after hip graft harvest This was much higher than the 8% reported to the operating surgeon Prospective phone survey
Heary et al. Neurosurgery 2002
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Recurrent laryngeal nerve
Incidence was 6.4% historically This neurologic deficit is very well tolerated by many patients Symptomatic patients report difficulty with the pitch and endurance of their voice. Dysphagia and aspiration can result With a simple intra-operative maneuver the incidence was reduced to 1.7%
Apfelbaum et al. Spine 2000
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Esophageal injury
Can be due to retraction or adhesion to anterior cervical plate Responsible for long-term dysphagia 2-3% Everything flush with spine
- Evidence from Arthoplasty IDE’s
- ACDF without plate
More mobilization of esophagus
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C5 palsy
Anterior and posterior Pathophysiology
- Vascular
- Geometry of the root
- Isolated supply of deltoid
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Biomechanics / Carpentry
Subsidence Pseudoarthrosis Manifest with
- Kyphosis
- Foraminal stenosis
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Biomechanical rational for dynamic plate
Rigid cantilever system IAR moves towards instrumentation Nutcracker effect
Foley, K et al
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Nutcracker effect
Paradoxical loading
- Grafts are loaded in extension,
unloaded in flexion
Much higher load forces
- Pistoning and subsidence
- Pseudoarthrosis
The nutcracker effect is minimized by the translation of a dynamic plate
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Controlled Subsidence
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Definitions
Rotationally Dynamic Translationally Dynamic
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Results
- Brodke. Anterior cervical fixation: analysis of load-sharing and stability with use of
static and dynamic plates. JBJS 2006
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Results
Pre-subsidence all performed similarly Post-subsidence
- Static plate lost 70% of load sharing
- Rotational and Translational dynamic maintained
load sharing
Clinical Caveat: Translational dynamic is a lot more difficult to insert
- Brodke. Anterior cervical fixation: analysis of load-sharing and stability with use of
static and dynamic plates. JBJS 2006
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Controlled subsidence
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Adjacent level disease
Discussed by Hilibrand et al in 1999 Pathophysiology is debated
- Direct result of the fusion
- Result of underlying disease
Incidence is 3% per year
Hilibrand et al. Journal of Bone and Joint Surgery 1999
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Stand Alone Cage
Most current iteration of ACDF Addresses the shortcomings just presented Has been used for quite some time in Europe Was introduced to US in an IDE study in 2001
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Minimal graft harvest morbidity
Bone Marrow Aspirate
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CT @ 12 months
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Facilitates treatment of adjacent level
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