5/31/2013 DEPARTMENT OF ORTHOPAEDIC SURGERY DEPARTMENT OF ORTHOPAEDIC SURGERY UNIVERSITY OF CALIFORNIA SAN FRANCISCO UNIVERSITY OF CALIFORNIA SAN FRANCISCO Do We Know Everything About LBP? Department Support Disclosure AIOD-Assn Intl l'Osteosynthese Dynamique Musculoskeletal Transplant Foundation Aleeva Medical, Inc. NIH Natl Inst Arthr, Musculoskel & Skin NIH Natl Inst Dental & Craniofacial Res. American College of Sports Medicine Fdn 8 TH ANNUAL North American Spine Society American Orthopaedic Soc for Sports Med North Shore-Long Island Jewish Hlth Sys Agency for Healthcare Research and Quality Novo Nordisk AO Foundation Orthologic Corporation Arthritis Foundation Orthopaedic Research and Education Fdn. UCSF SPINE SYMPOSIUM Arthrocare Corporation Orthopaedic Trauma Association Arthroscopy Association of North America Scios, Inc., a Johnson & Johnson Co. Biomet, Inc. Scoliosis Research Society Canadian Academy of Sports Medicine Smith and Nephew, Inc. San Francisco, 2013 Columbia University Spinal Kinetics, Inc. Deafness Research Foundation SpinalMotion, Inc. Stryker Corporation DePuy Inc., a Johnson & Johnson Company Stryker Howmedica Osteonics Hacettepe University Synthes USA Harold K. L. Castle Foundation TissueLink Medical, Inc. Histogenics Corporation TranS1, Inc. Intl Spinal Injection Society UC Berkeley ISTO Technologies, Inc. United Health Group Company Kyphon University of Minnesota March of Dimes Birth Defects Foundation Sibel Demir-Deviren, MD University of Texas at Dallas Medtronic, Inc. Wisconsin Alumni Research Foundation Zimmer, Inc. Associate Clinical Professor Spine Center 10/15/2007 University of California, San Francisco Paraspinal Muscles in Patients with LBP Paraspinal Muscles in Patients with LBP Low Back Pain Low Back Pain 4 70-80% of adults experience at least 1 episode 4 70-80% of adults experience at least 1 episode Several studies Several studies of LBP of LBP have emphasized have emphasized the important role the important role 4 40% experience a second episode within 6 4 40% experience a second episode within 6 of paraspinal of paraspinal months months muscle muscle 4 Patients suffering from LBP consume more 4 Patients suffering from LBP consume more morphology on morphology on than $90 billion annually than $90 billion annually the etiology, the etiology, prognosis and prognosis and management management 1
5/31/2013 4 Theories on the role of 4 Theories on the role of these muscles arose these muscles arose from imaging studies from imaging studies suggesting suggesting h smaller multifidus h smaller multifidus cross-sectional area cross-sectional area (CSA) (CSA) h more fatty infiltration h more fatty infiltration as compared with as compared with healthy asymptomatic healthy asymptomatic controls. controls. Multifidus Muscle Multifidus Muscle Multifidus Muscle Multifidus Muscle 4 The lumbar multifidus 4 The lumbar multifidus 4 Control the 4 Control the is considered to be a is considered to be a intersegment motion of intersegment motion of vital stabilizer of lumbar vital stabilizer of lumbar the individual vertebrae the individual vertebrae spine spine 4 Any atrophy or injury to 4 Any atrophy or injury to 4 Multifidus alone is 4 Multifidus alone is the multifidus muscle is the multifidus muscle is responsible for more responsible for more expected to expected to than two thirds of the than two thirds of the compromise spinal compromise spinal muscular stiffness in the muscular stiffness in the function function sagittal plane sagittal plane 2
5/31/2013 Multifidus and paraspinal muscle group are Multifidus and paraspinal muscle group are Multifidus Muscle Multifidus Muscle smaller in patients with chronic LBP than healthy smaller in patients with chronic LBP than healthy controls controls 4 Chronic denervated 4 Chronic denervated muscle is best seen on muscle is best seen on magnetic resonance magnetic resonance images (MRI) as loss of images (MRI) as loss of muscle bulk and muscle bulk and widespread areas of widespread areas of increased signal increased signal intensity resulting from intensity resulting from fatty infiltration fatty infiltration 4 Fatty Infiltration in the lumbar extensors is a 4 Fatty Infiltration in the lumbar extensors is a Multifidus Muscle Multifidus Muscle common finding in patients with CLBP which common finding in patients with CLBP which correlates with poor physical performance, and correlates with poor physical performance, and 4 It is difficult to 4 It is difficult to disability disability measure cross measure cross sectional area with sectional area with diffuse fatty diffuse fatty infiltration infiltration 3
5/31/2013 MRI IDEAL Images MRI IDEAL Images Multifidus Muscle Multifidus Muscle Average % fat Average % fat 4 Patients with chronic LBP appear to have 4 Patients with chronic LBP appear to have deposition (1.97 – deposition (1.97 – more multifidus atrophy at L5 than L4 more multifidus atrophy at L5 than L4 2.4%) in 2.4%) in 4 Patients with chronic unilateral LBP have 4 Patients with chronic unilateral LBP have paraspinal paraspinal smaller muscles on the symptomatic side as smaller muscles on the symptomatic side as muscles in a muscles in a compared with the asymptomatic side. compared with the asymptomatic side. healthy subject healthy subject Multifidus Muscle Multifidus Muscle Paraspinal Muscles and LBP Paraspinal Muscles and LBP 4 Multifidus atrophy is associated with poor functional 4 Multifidus atrophy is associated with poor functional 4 Possible mechanisms for muscle atrophy 4 Possible mechanisms for muscle atrophy outcomes after disc surgery outcomes after disc surgery h Disuse h Disuse 4 Muscle fatigue leads to changes in muscle 4 Muscle fatigue leads to changes in muscle recruitment patterns, increases in spinal force, and recruitment patterns, increases in spinal force, and h Muscle denervation h Muscle denervation decreases in spinal stability decreases in spinal stability h Reflex inhibition h Reflex inhibition h Iatrogenic h Iatrogenic 4
5/31/2013 Innervation of Multifidus Muscle Innervation of Multifidus Muscle Medial branch nerve Medial branch nerve 4 Multifidus muscles have 4 Multifidus muscles have 4 Multifidus muscle 4 Multifidus muscle monosegmental monosegmental innervation innervation 4 Facet joint 4 Facet joint 4 L1 multifidus is 4 L1 multifidus is 4 Pars interarticularis 4 Pars interarticularis innervated by L1 medial innervated by L1 medial branch nerve branch nerve 4 L5 MM by L5 medial 4 L5 MM by L5 medial branch nerve branch nerve Radiofrequency ablation of medial Radiofrequency ablation of medial Radiofrequency ablation of medial Radiofrequency ablation of medial branch nerve for facetogenic pain branch nerve for facetogenic pain branch nerve for facetogenic pain branch nerve for facetogenic pain 4 For L5-S1 facet joint, we ablate L4 and L5 4 For L5-S1 facet joint, we ablate L4 and L5 4 On the purpose of helping patients for 6-12 4 On the purpose of helping patients for 6-12 medial branch nerves medial branch nerves months months 4 For L4-5 facet joint, we ablate L3 and L4 4 For L4-5 facet joint, we ablate L3 and L4 4 Iatrogenic multifidus atrophy 4 Iatrogenic multifidus atrophy MBNs MBNs 4 We don’t know the long term effects 4 We don’t know the long term effects 4 For L3-4 facet joint, we ablate L2 and L3 4 For L3-4 facet joint, we ablate L2 and L3 MBNs MBNs 5
5/31/2013 Biomechanic Studies at UCSF Biomechanic Studies at UCSF Biomechanic Studies at UCSF Biomechanic Studies at UCSF 4 Multifidus activation 4 Multifidus activation 4 This extent of lordosis 4 This extent of lordosis increased lordosis in increased lordosis in loss is consistent with loss is consistent with the unweighted spine the unweighted spine that observed in human that observed in human subjects with multifidus subjects with multifidus 4 Reduction in multifidus 4 Reduction in multifidus atrophy atrophy force decreased force decreased lordosis in the weighted lordosis in the weighted spine spine Biomechanic Studies at UCSF Biomechanic Studies at UCSF Biomechanic Studies at UCSF Biomechanic Studies at UCSF 4 When the 4 When the atrophied multifidus atrophied multifidus 4 This caused an 4 This caused an was represented, was represented, increase in overall increase in overall the erector spinae the erector spinae spine compression spine compression force needed to force needed to of 28% percent of 28% percent increase by 46% to increase by 46% to maintain trunk maintain trunk NIH Grant 1R01AR060729-01 NIH Grant 1R01AR060729-01 posture posture 6
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