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 Woman’s Hospital Harvard Medical School
Disc losur e s De puy Spine Co nsulting Gra nt suppo rt Bio me t Spine Co nsulting Gra nt suppo rt
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
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
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
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
C5 palsy Anterior and posterior Pathophysiology • Vascular • Geometry of the root • Isolated supply of deltoid
Biomechanics / Carpentry Subsidence Pseudoarthrosis Manifest with • Kyphosis • Foraminal stenosis
Biomechanical rational for dynamic plate Rigid cantilever system IAR moves towards instrumentation Nutcracker effect Foley, K et al
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
Controlled Subsidence
Definitions Rotationally Dynamic Translationally Dynamic
Results Brodke. Anterior cervical fixation: analysis of load-sharing and stability with use of static and dynamic plates. JBJS 2006
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
Controlled subsidence
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
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
Bone Marrow Aspirate Minimal graft harvest morbidity
CT @ 12 months
Facilitates treatment of adjacent level
T ha nk Yo u!
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