3History1944Knuttson: Method of diagnosing segmental instability by measuring sagittal plane translation and rotation with lateral flexion/extension radiographs, then compared to normal ranges
4History1944Knuttson: Method of diagnosing segmental instability by measuring sagittal plane translation and rotation with lateral flexion/extension radiographs, then compared to normal ranges
5History White and Panjabi: Defined criteria for diagnosing instability 19901944White and Panjabi: Defined criteria for diagnosing instability-Sagittal translation > 4.5mm, or > 15% vertebral body width-Sagittal rotation > 15o at L1-2, L2-3, or L3-4,> 20o at L4-5 or 25o at L5-S1
6History White and Panjabi: Defined criteria for diagnosing instability 19901944White and Panjabi: Defined criteria for diagnosing instability-Sagittal translation > 4.5mm, or > 15% vertebral body width-Sagittal rotation > 15o at L1-2, L2-3, or L3-4,> 20o at L4-5 or 25o at L5-S1
7History199219901944Panjabi: presents a conceptual model of the spinal stabilization system, the neutral zone and clinical instability
8History199219901944Panjabi: presents a conceptual model of the spinal stabilization system, the neutral zone and clinical instability
9History1992Today19901944Multiple studies on lumbar clinical instability and its role in LBPHow far have we come in nearly 70 years?
10Definitions Clinical Instability (Panjabi, 1992) “A significant decrease in the capacity of the stabilizing system of the spine to maintain the intervertebral neutral zones within the physiological limits so that there is no neurological dysfunction, no major deformity, and no incapacitating pain”
11Stabilization System (3 Subsystems) Vertebrae Facets Discs Ligaments MusclesTendonsActiveNeural ControlPassiveThe Stabilization System is divided into 3 subsystems that are in constant interaction.CNSNervesFeedback System
12Subsystem Dysfunction? ActiveNeural ControlPassiveCompensatory response from other subsystems
13Response to Subsystem Dysfunction ActiveNeural ControlPassiveResponse to Subsystem DysfunctionConceptual ResponseImmediate successful compensation from other subsystemsLong-term compensation from one or more subsystemsInjury to one or more subsystemsConceptual OutcomeNormal FunctionNormal function with altered stabilization systemOverall system dysfunction, LBP
14Definitions Clinical Instability (Panjabi, 1992) “A significant decrease in the capacity of the stabilizing system of the spine to maintain the intervertebral neutral zones within the physiological limits so that there is no neurological dysfunction, no major deformity, and no incapacitating pain”
15Neutral Zone“That part of the range of the intervertebral motion, measured from the neutral position, within which the spinal motion is produced with a minimal internal resistance.” (Panjabi)Zone of high flexibility or laxityPortion of the range of motion that is highly flexible
16Elastic Zone“That part of the physiological intervertebral motion, measured from the end of the neutral zone up to the physiological limit.”Zone of high stiffness/resistancePortion of the ROM that is highly stiff
17Diagram of IV movement(Biely et al.) High LaxityZone ROMWeakness or InjuryZone ROMStrengthening, Osteophytes, FusionHigh ResistanceNeutral Zone may increase with injury or weakness and may decrease by strengthening, osteophyte formation and surgical fusion.Neutral Zone + Elastic Zone = Physiological ROM
19DefinitionsRadiographic Instability: No standardized definition
20Radiographic Limitations Lateral Flexion/Extension:No standardized procedureFalse positivesVariation in asymptomatic subjectsVariable limits for cutoff values to diagnose instabilitySlight variation in patient position of direction of beam can produce 10%-15% variation in displacement measureProvides no information about the active and neural componentsProvides no information on what is occurring within rangeCan not reliably correlate abnormal image to pain/disabilityClinical instability can exist without radiographic evidence of instabilityA definition for radiographic instability in uncertain as is the measure of lateral flexion/extension radiograph due to several confounding factors. Therefore, the diagnosis of clinical instability can not solely be produced from imaging
21Validity of Clinical Instability ADTOAre assessment protocols/tools available to accurately/reliably diagnose clinical instability?Once clinical instability is diagnosed, is there agreement on an established treatment?What is the best treatment for lumbar instability?Spratt KF, Weinstein JN. Chapter 25: Measuring clinical outcomes. In: Weisel S, ed. The Lumbar Spine. 2nd ed. v. 2. Philadelphia: W.B. Saunders Co., 1996:
22PrevalenceDepending on the cutoff limits and the study12% of patients manually assessed for lumbar segmental instability (Abbott JH, McCane B, Herbison P, Moginie G, Chapple C and Hogarty T. Lumbar segmental instability: a criterion-related validity study of manual therapy assessment. BMC Musculoskeletal Disorders. 2005;6:56. doi: / )57% patients referred for flex/ext radiographs based on suspicion of instability (Fritz JM, Piva SR, Childs JD. Accuracy of the clinical examination to predict radiographic instability of the lumbar spine. Eur Spine J. 2005;14:There is a wide range of prevalence dependent on assessment methods
23Is Lumbar Instability a Valid Subgroup? Abbott et al. (2006) concluded lumbar segmental mobility disorders are a valid means of defining sub-groups within NSLBP in a conservative care population of patients with recurrent CLBPProspective cohort of 138 consecutive patients with RCLBP, Roland Morris and VAS scores obtainedSagittal angular rotation and translation of each lumbar segment was measured on radiograph then compared to reference range derived from a study of 30 asymptomatic volunteersLumbar Segmental Mobility Disorder (LSMD) defined as 2sd from reference meanNormal reference intervals developed using 2 models (Gaussian, novel normalized within-subjects)Rotational Instability: 23%Translational Instability: 32%Radiographic metholody was identical for symptomatic and asymptomatic groups with high reliability
24Is Lumbar Instability Associated with pain/disability? LSMDs are a valid means of defining sub-groups within NSLBPAbbott et al.(2006): Among patients with RCLBP, presence of any LSMD, regardless of how defined, does not appear to be strongly associated with greater levels of pain or disability compared to patients with other forms of NSLBP without LSMDsShort answer: NO. +/- LSMDs, pain/disability is the same within the black box of NSLBP
25Assessment to Diagnosis Abdullah et al. Clinical Test to Diagnose Lumbar Segmental Instability: A Systematic ReviewHicks et al. Interrater Reliability of Clinical Examination Measures for Identification of Lumbar Segmental InstabilityHicks et al. Preliminary Development of a Clinical Prediction Rule for Determining Which Patients With LBP Will Repsond to a Stabilization Exercise ProgramAbbott et al. Lumbar Segemental Mobility Disorders: Comparison of Two Methods of Defining Abnormal Displacement Kinematics in a Cohort of Patients with NSLBPDemoulin et al. Lumbar Functional Instability: A Critical Appraisal of the LiteratureFritz et al. Accuracy of the Clinical Examination to Predict Radiographic Instability of the Lumbar SpineAbbott et al. Lumbar Segmental Instability: A Criterion-Related Validity Study of Manual Therapy AssessmentCook et al. Subjective and Objective Descriptors of Clinical Lumbar Spine Instability: A Delphi StudyKasai et al. A New Evaluation Method for Lumbar Spinal Instability: Passive Lumbar Extension TestIn an attempt to answer the question of consistently accurate diagnostics, I reviewed several studies
26Study Mix Prospective Cohorts: 5 Single group repeated measure interrater reliability study: 1Critical Appraisal of Literature: 1Delphi Study: 1Systematic Review: 1
27Assessment to Diagnosis Tests/Criteria Available HistoryPassiveActiveAge less than 40Beighton Ligamentous Laxity ScaleProne Instability Test“Giving way” “Giving out” “Catching” “Locking”Avg SLR > 91oAberrant MotionsTemp. Relief with bracingPassive Lumber Extension TestTotal Flexion > 53oSelf manipulatorPosterior Shear TestTotal Extension > 26oPain with transitionsPAIVMSit to stand testPain with sudden movementPPIVM (flexion)Instability Catch SignDifficulty sitting unsupportedPPIVM (extension)Painful Catch SignDifficulty with static positionsStep offApprehension SignFrequent muscle spasmsLack of hypomobilityGower’s SignFear with movementSegmental HingingRecurrent episodesReversal of Lumbopelvic RhythmProgressively worsening
28Assessment to Diagnosis Tests/Criteria with high +LR(Diagnostic Accuracy) +LR Shift in Probability>10 Large5-10 Moderate2-5 Small1-2 Very smallHistoryPassiveActiveAge less than 40 (3.7)Beighton Ligamentous Laxity Scale (2.5)Prone Instability Test (1.7)“Giving way” “Giving out” “Catching” “Locking”Avg SLR > 91o (3.3)Aberrant Motions (1.6)Temp. Relief with bracingPassive Lumber Extension Test (8.8)Total Flexion > 53o (1.3)Self manipulatorPosterior Shear Test (1.1)Total Extension > 26oPain with transitionsPAIVM (2.4)Sit to stand test (infinite, selection bias)Pain with sudden movementPPIVM (flexion) (8.7, 95% CI: 0.6, 134.7)Instability Catch Sign (1.8)Difficulty sitting unsupportedPPIVM (extension) (7.1, 95% CI: 1.7, 29.2)Painful Catch Sign (1.4)Difficulty with static positionsStep offApprehension Sign (1.6)Frequent muscle spasmsLack of hypomobility with PA (5.0)Gower’s SignFear with movement (1.4)Segmental HingingRecurrent episodesReversal of Lumbopelvic RhythmProgressively worseningWide CI indicates imprecision in the estimate
29Assessment to Diagnosis Tests/Criteria with high reliability HistoryPassiveActiveAge less than 40Beighton Ligamentous Laxity ScaleProne Instability Test (k= )“Giving way” “Giving out” “Catching” “Locking”Avg SLR > 91oAberrant Motion with Trunk Motion (k=-0.07,0.60)Temp. Relief with bracingPassive Lumber Extension Test (high test-retest reliability, however no k value)Total Flexion > 53oSelf manipulatorPosterior Shear Test (k=0.27)Total Extension > 26oPain with transitionsPAIVM hypermobile (k=0.48) hypo (k=0.38)Sit to stand testPain with sudden movementPPIVM (flexion) (-0.02, 0.26)Instability Catch SignDifficulty sitting unsupportedPPIVM (extension) (-0.02, 0.26)Painful Catch SignDifficulty with static positionsStep offApprehension SignFrequent muscle spasmsLack of hypomobility with PA (k=0.30)Gower’s SignFear with movementSegmental HingingRecurrent episodesReversal of Lumbopelvic RhythmProgressively worsening
30Assessment to Diagnosis Tests/Criteria Available (Multivariate) Hicks GE, Fritz JM, Delitto A, McGill SM. Preliminary development of a clinical prediction rule for determining which patients with low back pain will respond to a stabilization exercise program. Arch Phys Med Rehabil 2005;86:Variables in the Clinical Prediction Rule(CPR) for success with stabilization treatmentAge less than 40 y/o(+) Prone Instability Test(k=0.69, 0.87)(+) Aberrant Movements (k=0.07,0.60)Avg SLR > 91o (ICC )No. of Variables Present+LR1 or more1.3 ( )2 or more1.9 ( )3 or more4.0 ( )No reliability score available for 3 or more tests, however Kappa for PIT, SLR and Aberrant Motions listed above.If Aberrant Movements are among the 3 tests, reliability would decrease significantly, along with validity
31Assessment to Diagnosis Tests/Criteria Available (Multivariate) Hebert JJ, Koppenhaver SL, Magel JS, Fritz JM. The relationship of transversus abdominis and lumbar multifidus activation and prognostic factors for clinical success with a stabilization exercise program: a cross-sectional study. Arch Phys Med Rehabil 2010;91:78-85.Predictors of clinical success with aspinal stabilization exercise program(+) Prone Instability Test (k=0.69, 0.87)(+) Aberrant Movement (k=0.07,0.60)Avg. SLR > 90o (ICC )(+) Hypermobility with PA (k=0.30)# of prognostic factors = LM activationNo relation between prognostic factors and TrANo Sn/Sp calculated, No LRsNo. + Prognostic FactorsThe role of LM in spinal stabilization is controversial
32Assessment to Diagnosis Summary The Passive Lumber Ext Test is not validated, however comes the closestGeneral consensus of nearly all studies is that diagnosis should not occur with one clinical test, but rather a cluster of signs/testsDoes using multiple unreliable, inaccurate tests add clarity?Lack of correlation between radiographic findings and clinical symptoms increases uncertaintyIf a diagnosis can not reliably and accurately be established, can there be agreement on treatment?
33Validity of Clinical Instability ADTOAre assessment protocols/tools available to accurately/reliably diagnose clinical instability?Once clinical instability is diagnosed, is there agreement on an established treatment?What is the best treatment for lumbar instability?
34Diagnosis to Treatment Agreement on established treatment? Several studies agree“Stabilization exercise”“Stabilizing Exercise”“Trunk Muscle Stabilization Training”How this is carried out varies considerablyConcentric, Eccentric, IsometricMuscle Firing, Sequencing, PatterningPosition, Resistance, RepsProgressionFeedback: US, EMG, Tactile, Visual
35Diagnosis to Treatment Agreement on established treatment? The most frequently cited study for exercise protocol:Richardson CA, Jull GA. Muscle control – pain control. What exercises would you prescribe? Manual Therapy 1995;1:2-10.Isometric co-contraction of the TrA and Multifidus with a static neutral spineFocus on precise muscle action with re-education of this contraction in:QuadripedProneUpright positionsEventual functional training
36Diagnosis to Treatment Diagnosis to Treatment Is Stabilization Exercise doing what we think it is?McGill et al. proposed that no single muscle is the best stabilizer of the spine. Multiple muscles are required dependent on the task.This muscle activation produces stability:Muscles acting as ‘guywires’Compression/Loading through antagonistic activityStokes et al. : Analytical study of a biomechanical modelSpinal Stability increased with increased intra-abdominal pressure (IAP)Forced component activation of abdominals decreased lumbar stabilityIAP generates an extension momentCan this extension moment inadvertently have an effect?
37Diagnosis to Treatment Summary Spinal StabilizationSpecific Muscle Activation/Recruitment/FiringGross core activationIntra-Abdominal PressureOther / AllA general framework of treatment
38Validity of Clinical Instability ADTOAre assessment protocols/tools available to reliably diagnose clinical instability?Once clinical instability is diagnosed, is there agreement on an established treatment?What is the best treatment for lumbar instability?
39Treatment to Outcome Diagnosed Radiographic Instability O’Sullivan (1997): …patients with CLBP and radiologic diagnosis of spondylolysis or spondylolisthesis.Results: A “specific exercise” approach decreased pain/disability/pain medication use significantly more than other commonly prescribed conservative treatment programs in patients with chronically symptomatic spondylolysis/spondylolisthesis.Kumar (2011):…patients with lumbar segmental instability.Results: Segmental stabilization exercise was more effective than placebo intervention in symptomatic lumbar segmental instability.O’Sullivan (2011) Editorial:…’instability’ should be reserved solely for ‘unstable fractures’ and ‘unstable spondylolisthesis’.Lets look at the outcome of a matching treatment to diagnosed instability or suspicion of instability. Subgrouping the subject population improved the outcome of the matched treatment
40Treatment to Outcome Absence of Instability Koumantakis (2005): …patients with RCLBP and no clinical signs suggesting spinal instabilityConclusion: Stabilization exercises do not appear to provide additional benefit to patients with subacute or CLBP who have no clinical signs suggesting the presence of spinal instabilityRachwitz (2006):…patients with acute, subacute and CLBPConclusion: For LBP, segmental stabilizing exercises are more effective than treatment by GP (walking, stretching, swimming, education, active rest, out of work, traction, STM), but they are not more effective than other physiotherapy interventions.Macedo (2012):…patients with CLBPConclusion: The results of this study suggest that motor control exercises and graded activity have similar effects for patients with chronic nonspecific low back pain.
41RecurrenceHides JA, Jull GA, Richardson CA. Long-term effects of specific stabilizing exercises for first-episode low back pain. Spine 2001;26:1 and 3 year follow-up of exercise group (Richardson,Jull) vs. control group after acute, first-episode LBP.1 year after treatment:specific exercise recurrence was 30%, control was 84%2-3 years after treatment:specific exercise recurrence was 35%, control was 75%Hides and others did a follow-up study to the original 1996 study to document the the natural course of LM recovery and the effectiveness of specific exercise on muscle recoveryPatients of both groups most commonly reported precipitating incidents of recurrence related to liftingLifting is a flexion-based movementDP was not ruled out initiallyPrevalence data shows that up to 90% of patient’s with acute LBP have a DP
42Validity of Clinical Instability ADTOAre assessment protocols/tools available to accurately/reliably diagnose clinical instability?Once clinical instability is diagnosed, is there agreement on an established treatment?What is the best treatment for lumbar instability?
43Instability may be a valid subgroup Cloudy ADTO LinkageInstability may be a valid subgroupStabilization Exercise may be effective
44Where do I start? With the suspicion of instability (history) Cook C, Brismee JM, Sizer PS. Subjective and objective descriptors of clinical lumbar spine instability: a delphi study. Manual Therapy 2006;11:11-21122 PTs with OCS and/or FAAOMPT training responded fully to create a consensus on the subjective and objective symptoms associated with clinical instability of the spine.Ranked lists of subjective and object reports were createdFritz (2005):…patients with LBP referred for flexion-extension radiographs due to suspicion of lumbar instabilityConclusion: Prevalence is much higher in this study (57%) compared to other studies.
45Top 10 subjective reports associated with clinical instability Reports feeling of “giving way” or back “giving out”Self manipulator who feels the need to frequently crack or pop the backFrequent bouts or episodes of symptomsHistory of painful catching or locking during twisting or bending of the spinePain during transitional activities (e.g. sit to stand)Greater pain returning to erect position from flexionPain increased with sudden, trivial, or mild movementsDifficulty with unsupported sitting and better with supported backrestWorse with sustained postures and a decreased likelihood of reported static position that is not painfulCondition is progressively worsening (e.g. shorter intervals between bouts)
46What Can I Do Monday?History that suggests instability, +/- radiographic diagnosisCatching / Locking / Giving out / Pain with sudden movementsRule out Directional PreferenceIf DP can be ruled out, history suspicious of instability becomes more relevantPerform tests, use criteria with the best available evidence (diagnostic accuracy/reliability)Passive Lumbar Extension TestAge < 40 y/oAvg SLR > 91oPerform Lumbar Stabilization Exercise per Richardson and JullProgress to patient specific functional limitations
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