CLINICAL ASSESSMENT OF STABILITY DYSFUNCTION

Transcription

1 CLINICAL ASSESSMENT OF STABILITY DYSFUNCTION Dysfunction can be evaluated, quantified and compared against a normal measure, ideal standard or some validated benchmark. The measurement of dysfunction, followed by intervention with some form of treatment or therapy over an appropriate time frame and the re assessment of dysfunction to demonstrate a positive outcome of intervention provides the framework of good clinical practice. Dysfunction is indirectly related to pathology but as the pathology heals and the symptoms subside the dysfunction does not always automatically return to a normal baseline. To date, measurement of motor control related stability dysfunction has required complex measurement tools (EMG and Imaging Ultrasound) and highly specific training to use and interpret the results. There has been a need to develop a clinic friendly measurement system that is simple, easy to learn, quick and can be used to assist clinical decision making about when to progress and when there is no longer a need to continue training a particular exercise or muscle. A rating system for assessment and re assessment of motor control related stability dysfunction has been developed to address this need. RATING SYSTEM This rating system does not rate or measure inhibition of muscle function. A certain amount of inhibition or dysfunction can be assumed due to pain and pathology. Instead this rating system evaluates low threshold voluntary recruitment efficiency. It is probable that if low threshold voluntary recruitment efficiency is good, then when the pain or pathology disappears the muscle may automatically return to normal (ideal) function. The observation that some people get better and return to ideal function without any specific retraining supports this. However, if the low threshold voluntary recruitment efficiency is poor, then when the pain or pathology disappears, the dysfunction in the muscle is more likely to persist. This assessment of recruitment efficiency helps to determine priorities of clinical management while re assessment helps guide progression. Two parameters are evaluated. The first parameter tests the ability to perform a specific motor control recruitment pattern or movement correctly. The second parameter assesses the efficiency of low threshold recruitment in the performance of that motor control skill. It is essential that the patient understand the test movement or activation required. To pass the test ( ) the subject needs to demonstrate the correct recruitment pattern or movement without substitution (for the first ) and demonstrate that it can be easily controlled to benchmark standards without fatigue or high sensation of effort (for the second ) If the patient fails a test (i.e. rates or ), it is important that this is because they cannot perform the test, not because they are not sure what to do. Verbal description, visual demonstration, hands on facilitation and visual or tactile self feedback should be used to ensure that the patient understands and has experienced the movement or activation required before rating the efficiency of low threshold voluntary recruitment. The correction or rehabilitation of motor control stability dysfunction has been shown to decrease the incidence of recurrence of pain. Along with symptom management this is a primary short term goal of therapeutic intervention. The patient frequently becomes symptom free before dysfunction is fully corrected. Treatment should not necessarily cease just because the symptoms have disappeared if measurable dysfunction persists. A rating system (such as this one) for the assessment and re assessment of dysfunction is necessary to justify this in clinical practice. 1

2 CONTROL of DIRECTION RATING SYSTEM Rate the ability to dissociate the directional dysfunction only. Do not rate the normal or functional movements. Each direction is assessed separately. ASSESS & RATE THE EFFICIENCY OF DIRECTION SPECIFIC CONTROL During the assessment and prioritisation of direction specific motor control and the diagnosis of stability dysfunction, there are several integral steps. Observe Natural Movement and Identify Contributing Factors: 1. Restriction: Note a loss of range of motion, either segmentally or multisegmentally, during the movement test. 2. Compensatory hypermobility to keep function: Note excessive range of movement or abnormal initiation of movement at the site that the patient complains of symptoms Test for Give (Stability Dysfunction): Hold neutral and prevent give into test direction and (a) move the adjacent joint (above or below) or (b) move the same joint in a different direction. Assess the patient s ability to actively control the give and move independently at the adjacent joint in the direction of stability dysfunction. (That is, dissociate movement at the restriction from the give.) This is the aspect that is rated as assessment of recruitment efficiency. Relate Dysfunction to Symptoms: Direction of give to direction of symptom provocation: (a) Does the site of give (or the site of poor stability control) relate to the site that the patient complains of as the source of symptoms? (b) Does the direction of movement or load testing relate to the direction or position of provocation of symptoms? This identifies clinical priorities! CONTROL OF DIRECTION MOTOR CONTROL TEST PROCEDURE Start Position: Position in the patient s neutral training region as close as possible to the anatomical ideal position Therapist instructs the patient in the test movement: control give + move adjacent joint (VAK): o Visually demonstrate the test movement or action (if able) o Verbally explain and describe the test movement or action o Manually facilitate or hands on guide the patient through the test movement or action (if possible) Therapist facilitates the test action and guides the elimination substitution strategies then passively stabilises the test region and assesses the passive available range of the test movement Patient actively practices the movement with visual and palpation feedback, unloading (if required), therapist support ( hands on facilitation) and verbal correction. Usually, 3 8 repetitions are sufficient for teaching and learning. 2

3 Test When therapist is confident that the patient understands the test movement or action and knows what is expected the patient is required to perform the test without visual or tactile feedback, verbal facilitation, or corrective instruction. The therapist then rates the performance of the test. (Must achieve the benchmark and look & feel easy for rating) RATING REQUIREMENTS Stability dysfunction is present even if there is no excessive or hypermobile range, if the muscle stability system can t control normal range. Stability dysfunction may be nonsymptomatic. If there is hypermobile range, so long as the control of the benchmark is efficient there is no significant stability dysfunction. So long as the direction being tested has good control it can achieve a rating. If the ability to dissociate and control the give throughout the available range is efficient but the range available is significantly restricted, then to maintain normal function, stability is sacrificed and there is compensation for the restriction. This only rates until the restricted range is regained and the muscle control of normal function can be assessed. This is primarily a mobility dysfunction. The is qualified by the restriction. Note what structure lacks extensibility (if restriction is obvious). If the restriction is structural and therefore permanent, then there must be compensation elsewhere to maintain function. If the compensation has poor control (give) this obviously has implications for ongoing risk of recurrence. If the available range is excessive (significantly more than the benchmark standard), the requirements for control of direction are achieved if the subject can demonstrate good motor control of dissociation throughout the benchmark range only. This demonstrates efficient co ordination of motor control strategies related to the recruitment pattern required to control direction specific stress and strain. Control through hypermobile range is not assessed at this level. That is dealt with by the principles of Control through Range. DIAGNOSIS OF STABILITY DYSFUNCTION A rating or rating labels or diagnoses the stability dysfunction. The diagnosis should label both the SITE and the DIRECTION of give that is uncontrolled. Each direction is assessed separately! If during a test of one specific direction, a give into another direction is observed, then the stability dysfunction (i.e. Site and Direction) is at the site of poor control and in the direction of actual give. For example, if during a test of control of lumbar flexion, the lumbar spine gives into extension, there is likely to be a problem with stability function for lumbar extension. The ability to control this apparent stability dysfunction should be specifically assessed with extension related tests. However if there was no give into flexion, then flexion is not the direction of give and the flexion control test should be rated as. 3

4 Rating of Low Threshold Recruitment Efficiency for Control of Direction Correct dissociation pattern of movement prevent [site] give into [direction] and move [adjacent region] Able to prevent give into the test direction Dissociate through the available range (even if available range is less than benchmark) If there is more available range than the benchmark standard, only the benchmark range needs to be controlled Without holding breath (acceptable to use an alternate breathing strategy) Control during eccentric phase Control during concentric phase Looks easy, and in the opinion of the assessor, is performed with confidence Feels easy, and the subject has sufficient awareness of the movement pattern that they confidently prevent give into the test direction The pattern of dissociation is smooth during concentric and eccentric movement Range of dissociation at least meets the benchmark of [benchmark range] Does not (consistently) use movement into the opposite direction to prevent the give No extra feedback needed (tactile or visual) Without external support or unloading Relaxed natural breathing (even if not ideal so long as natural pattern does not change) No fatigue Correct Dissociation Pattern Recruitment Efficiency RATING INTERPRETATION The first relates to correct pattern of voluntary dissociation. The second relates to ideal low threshold recruitment. Always qualify a rating with the reason for that. = correct pattern and correct recruitment If all requirements for the first and all requirements for the second are demonstrated, then rate the test as = correct pattern but phasic recruitment If the test demonstrates all the requirements for the first but fails any of the requirements for the second, then rate the test as = inability to demonstrate the correct pattern If there is failure to achieve all of the requirements of the first, then rate the test as. Note what proportion of benchmark range can be controlled. 4

5 UNLOADING PATHOLOGY Retraining the motor control patterns to control direction specific stress and strain has the effect of unloading provocative mechanical stress and strain from pathological or pain sensitive structures. Thereby decreasing symptoms and allowing them the opportunity to heal without maintained provocation. ASSESSMENT OVERVIEW Observe Teach Test Rate Relate Rehab the natural or normal pattern of movement. Note relative stiffness : relative flexibility issues or restrictions and compensation the test movement or action using visual, auditory and kinaesthetic cues with feedback and support the patient s ability to reproduce the test movement or action without cuing, feedback or support the performance of the test in terms of voluntary low threshold recruitment efficiency ( = good motor control, while or = stability dysfunction) then poor performance ( or ) to the symptomatic area (high clinical priority) is required for stability dysfunction that relates to symptoms or pathology 5

6 CONTROL OF TRANSLATION IN NEUTRAL RATING SYSTEM Rate the efficiency of local muscle motor control recruitment in joint neutral ASSESS & RATE THE EFFICIENCY OF LOCAL MUSCLE MOTOR CONTROL The only valid or reliable assessment of the automatic recruitment of local stabiliser function reported in the literature is measured by fine wire EMG recordings of onset timing related to perturbation challenges. This method of assessment is not a realistic clinical tool. The timing delays, such as are identified with transversus abdominis dysfunction in back pain subjects, are consistently present in all back pain subjects and therefore this inhibition can be assumed if a patient presents with back pain. There is no need to clinically measure what is already known. There are certain, very specific, non functional recruitment skills that have been suggested as being effective in improving the recruitment function of muscles with a local stability role (Hodges and Richardson , Richardson et al 1999, Hides et al 2001, Jull 2000). There is significant anecdotal and individual case study support for these low threshold motor control retraining exercises. These recruitment strategies have only recently been validated with controlled group studies (Tsao & Hodges in press). The assessment system suggested here does not rate or measure inhibition of muscle function. Instead this rating system rates low threshold voluntary recruitment efficiency. It is probable that if low threshold voluntary recruitment efficiency is good, then when the pain or pathology disappears the muscle may automatically return to normal (ideal) function. The observation that some people get better and return to ideal function without any specific retraining supports this. However, if the low threshold voluntary recruitment efficiency is poor, then when the pain or pathology disappears, the dysfunction in the muscle is more likely to persist. This assessment of recruitment efficiency helps to determine priorities of clinical management while re assessment helps guide progression. CONTROL OF TRANSLATION (IN NEUTRAL) MOTOR CONTROL TEST PROCEDURE: Start Position: Position in the patient s neutral training region as close as possible to the anatomical ideal position Therapist instructs the patient in the test movement: specific local stabiliser recruitment (VAK): o Visually demonstrate the test movement or action (if able) o Verbally explain and describe the test movement or action o Manually facilitate or hands on guide the patient through the test movement or action (if possible) Therapist facilitates the test action and guides the elimination substitution strategies Patient actively practices the movement with visual and palpation feedback, unloading (if required), therapist support ( hands on facilitation) and verbal correction. Usually, 3 8 repetitions are sufficient for teaching and learning. Test When therapist is confident that the patient understands the test movement or action and knows what is expected the patient is required to perform the test without visual or tactile feedback, verbal facilitation, or corrective instruction. 6

7 The therapist then rates the performance of the test. (Must achieve the benchmark and look & feel easy for rating) RATING REQUIREMENTS No mobiliser dominance (no spinal or pelvic movement) Minimise phasic overload of the global stabilisers Sustain the contraction consistently for the benchmark time Breathe with a normal respiratory pattern whilst sustaining a consistent contraction. o No holding breath o No significant abnormal breathing pattern Loss of apical = co contraction rigidity Loss of basal (bucket handle or pump) Loss of diaphragmatic / stomach o When breathe: can t maintain consistent contraction o contraction & with breathing Loss of tonic recruitment No rotation rigidity Rating of Low Threshold Recruitment Efficiency for Control of Translation Correct activation pattern in unloaded posture: [description of activation] Sustained contraction 2 3 seconds (even if not consistent or asymmetry) Maintain control of the neutral position Without substitution or cocontraction rigidity Without holding breath (acceptable to use an alternate breathing strategy) Looks easy and feels easy (needs to have confidence and awareness of correct activation strategy) Consistent activation Benchmark standard (Time: 15 seconds x 2 repetitions) Relaxed natural breathing (even if not ideal so long as natural pattern does not change) No fatigue No extra feedback (tactile or visual) Good symmetry (compare sides) Able to recruit efficiently in [additional posture] (related to provocation) Correct Recruitment Strategy Recruitment Efficiency 7

8 RATING INTERPRETATION The first relates to correct activation pattern in an unloaded posture. The second relates to ideal low threshold recruitment. Always qualify a rating with the reason for that. = correct activation and correct recruitment If the muscle demonstrates all requirements for the first and all requirements for the second, then rate the test as = correct activation but phasic recruitment If the muscle demonstrates all the requirements for the first but fails any of the requirements for the second, then rate the muscle as = inability to demonstrate the correct activation If there is failure to achieve all of the requirements of the first, then rate the muscle as. Note the dominant substitution strategy. ASSESSMENT OVERVIEW Observe Teach Test Rate Relate Rehab the natural or normal pattern of movement. Note substitution for inefficient recruitment the test movement or action using visual, auditory and kinaesthetic cues with feedback and support the patient s ability to reproduce the test movement or action without cuing, feedback or support the performance of the test in terms of voluntary low threshold recruitment efficiency ( = good motor control, while or = stability dysfunction) then poor performance ( or ) to the symptomatic area (high clinical priority). is required for stability dysfunction that relates to symptoms or pathology 8

9 CONTROL THROUGH RANGE RATING SYSTEM The basis of this test is to assess the ability of muscles that have a global stability role to efficiently control the normal unloaded limb or trunk through its required functional range range. By passively providing proximal fixation, the limb stabilisers may be tested in isolation. However, good function needs effective proximal trunk and girdle stability for efficient limb movement. If local or global control of the trunk is poor, then even if the limb stabilisers are able to control through range, limb function may still be inefficient. The testing procedure developed here evaluates both aspects of this function. Rate the ability for global stability muscles to: i. Shorten and move the joint through to its full inner range ii. Isometrically hold that position (or any point in range) iii. Eccentrically control lowering against gravity (without loss of rotatory control or proximal trunk / girdle stability) iv. Concentrically and eccentrically control hypermobile outer range if present. Inner range can be considered to be the point where passive resistance is first engaged in the direction of muscle shortening (not the point of range achieved with passive overpressure). This system does not rate muscle strength. Each global stability muscle is assessed separately. CONTROL THROUGH RANGE MOTOR CONTROL TEST PROCEDURE Start Position: Position the patients trunk and girdles in their neutral position and allow the muscle to be tested to be relaxed in its mid range region Therapist instructs the patient in the test movement: muscle contraction into inner range (VAK): o Visually demonstrate the test movement or action (if able) o Verbally explain and describe the test movement or action o Manually facilitate or hands on guide the patient through the test movement or action (if possible) The therapist passively stabilises the trunk and girdle, then assists the limb through the test movement and assesses the passive range of the test movement The therapist facilitates the test action and guides the elimination of substitution strategies Patient actively practices the movement with visual and palpation feedback, unloading (if required), therapist support ( hands on facilitation) and verbal correction. Usually, 3 8 repetitions are sufficient for teaching and learning. Test When therapist is confident that the patient understands the test movement or action and knows what is expected the patient is required to perform the test without visual or tactile feedback, verbal facilitation, or corrective instruction. The patient performs the test movement using functional limb or trunk load (no external resistance) and without any external support and without substitution movements. The therapist then rates the performance of the test. (Must achieve the benchmark and look & feel easy for rating) 9

10 (i) (ii) (iii) RATING REQUIREMENTS Does muscle active inner range shortening = joint passive available range? o At the point that the muscle cannot shorten any further without substitution, instruct the patient to stop and hold position. This point is identified by: movement of the limb into a direction unrelated to the test muscles action, the loss of trunk or girdle neutral and cramping and strain. o At this point the therapist passively supports the limb and assesses if the muscle active = joint passive. If there is more passive range available, note how much and rate the muscle as and do not test holding time or eccentric lowering. If muscle active = joint passive, can the muscle support normal limb load in this position? o The therapist instructs the patient to take the weight of their limb again and assess if the muscle can support the limb for the benchmark time without losing holding position due to fatigue or muscle inefficiency. If the muscle can support the limb load in its inner (shortened) range position, can it eccentrically control the smooth steady return (lowering) through range (normal or hypermobile) without loss of rotation control of the limb or loss of trunk and girdle stability? o The therapist instructs the patient to slowly lower the limb down through range against gravity. Observe for smooth steady movement and maintenance of the rotation position of the limb and the neutral position of the trunk and girdle. Rating of Low Threshold Recruitment Efficiency for Control through Range With proximal fixation of the girdle and trunk, the muscle can actively shorten through the available (including hypermobile) passive joint range of [position of the muscle s combined actions] (muscle active = joint passive?) Concentrically shorten against functional load and gravity Can hold this position for at least 2 3 seconds Without substitution by other muscles Active unsupported proximal control Available range at least meets the Benchmark Range of: [required range of active shortening] Can hold position for 15 seconds x 2 repetitions) Can smoothly control the eccentric return including hypermobile outer range (+ rotation control) Without fatigue No external support, passive proximal fixation or unloading Relaxed natural breathing (even if not ideal so long as natural pattern does not change) Muscle Active = Joint Passive Recruitment Efficiency 10

11 If muscle active = joint passive only because there is significant restriction of joint passive range, then it only rates until the restricted range is regained and the muscle control of normal function can be assessed. Note what structure lacks extensibility (if restriction is obvious). When the benchmark minimum range is available the muscle needs to be reassessed to rate. Both left and right sides (limb muscles) should be assessed separately. If there is observable asymmetry of range (that at least meets the benchmark minimum), but there is equally good control of the range then both sides can be rated. Dominance may affect high threshold tests of strength but should not significantly influence low threshold tests of recruitment efficiency. RATING INTERPRETATION The first relates to correct pattern of voluntary concentric shortening through range. The second relates to ideal low threshold recruitment. Always qualify a rating with the reason for that. = correct pattern and correct performance If all requirements for the first and all requirements for the second are demonstrated, then rate the test as = correct pattern but inefficient performance If the muscle demonstrates all the requirements for the first but fails any of the requirements for the second, then rate the muscle as. Note the time of good control prior to fatigue starting. = incorrect pattern (muscle active joint passive) If there is failure to achieve all of the requirements of the first, then rate the muscle as. Note how much range can be controlled. ASSESSMENT OVERVIEW Observe Teach Test Rate Relate Rehab the natural or normal pattern of movement. Note inefficient recruitment and substitution the test movement or action using visual, auditory and kinaesthetic cues with feedback and support the patient s ability to reproduce the test movement or action without cueing, feedback or support the performance of the test in terms of voluntary low threshold recruitment efficiency ( = good motor control, while or = stability dysfunction) then poor performance ( or ) to the symptomatic area (high clinical priority). is required for stability dysfunction that relates to symptoms or pathology 11

12 CONTROL OF EXTENSIBILITY RATING SYSTEM General guideline for optimal bi articular muscle extensibility: With the proximal joint supported in its neutral or relative mid range position, the distal joint should ideally be able to move through full range without being limited by restrictions of muscle extensibility (supported by Kendall et al 1993). This is a general guide not an absolute rule! Rate the passive extensibility of the global mobility muscles (and the ability for global stability muscles to control compensatory give) during an active or active assisted stretch. Passive length can be considered to be the point where passive resistance limits motion in the direction of muscle lengthening, under limb load and gravity (not the point of range achieved with maximum manual overpressure). Each global mobility muscle is assessed separately. Both left and right sides (limb muscles) should be assessed separately Be aware that acute pathology and tissue sensitisation (and psychological factors such as fear avoidance) will produce guarding or protective responses that influence tests of extensibility and need to be considered when assessing muscle extensibility. CONTROL OF EXTENSIBILITY MOTOR CONTROL TEST PROCEDURE Start Position: Position the patient s trunk and girdles in their neutral position and allow the muscle to be tested to be relaxed in its mid range region Therapist instructs the patient in the test movement: muscle contraction into inner range (VAK): o Visually demonstrate the test movement or action (if able) o Verbally explain and describe the test movement or action o Manually facilitate or hands on guide the patient through the test movement or action (if possible) The therapist passively stabilises the trunk and girdle, then assists the limb through the test movement and assesses the passive range of the test movement The therapist facilitates the test action and guides the elimination substitution strategies. Patient actively practices the movement with visual and palpation feedback, unloading (if required), therapist support ( hands on facilitation) and verbal correction. Usually, 3 8 repetitions are sufficient for teaching and learning. Test When therapist is confident that the patient understands the test movement or action and knows what is expected the patient is required to perform the test without visual or tactile feedback, verbal facilitation, or corrective instruction. The patient performs the test movement using functional limb or trunk load (no external resistance) and without any external support and without substitution movements. The therapist then rates the performance of the test. (Must achieve the benchmark and look & feel easy for rating) 12

13 RATING REQUIREMENTS (i) Does muscle passive available elongation = benchmark extensibility? o The patient actively stabilises the trunk (+/ passive therapist support) and girdle in a neutral position. The therapist then passively assists the limb through the test movement and assesses the passive range of the muscle extensibility. (If the muscle cannot achieve the passive benchmark it rates as.) (ii) If muscle passive elongation = the benchmark extensibility, is there sufficient proximal stability to allow functional use of the muscles extensibility potential? o The patient attempts to reproduce the test movement actively without any external support and without substitution movements. Proximal trunk and girdle position or stability must be maintained throughout. Rating of Low Threshold Recruitment Efficiency for Extensibility The muscle can passively lengthen to the benchmark standard (therapist controlled) [minimum extensibility required for good function] Active elongation (stretch) can reproduce the passive benchmark With good active control of proximal stability Without compensatory give (relative flexibility) No external support or assistance Sufficient Extensibility Recruitment Efficiency RATING INTERPRETATION The first relates to sufficient passive extensibility of the muscle. The second relates to the influence of relative flexibility : relative stiffness on active voluntary stretch loading. Always qualify a rating with the reason for that. = ideal extensibility and ideal active control If all requirements for the first and all requirements for the second are demonstrated, then rate the test as = ideal extensibility but poor active control If the muscle demonstrates all the requirements for the first but fails any of the requirements for the second, then rate the muscle as. Note the compensatory give (relative flexibility) or relative stiffness fault. = poor extensibility If there is failure to achieve all of the requirements of the first, then rate the test as. Note the available passive extensibility. 13

14 ASSESMENT OVERVIEW Observe Teach Test Rate Relate Rehab the natural or normal pattern of movement. Note relative stiffness or restriction issues and dominance the test movement or action using visual, auditory and kinaesthetic cues with feedback and support the patient s ability to reproduce the test movement or action without cuing, feedback or support the performance of the test in terms of voluntary low threshold recruitment efficiency ( = good motor control, while or = stability dysfunction) then poor performance ( or ) to the symptomatic area (high clinical priority). is required for stability dysfunction that relates to symptoms or pathology 14