Lumbar Spine Functional Instability Rehabilitation Convention or Evidence? Paul Schoonman, DC Schoonman Chiropractic and RehabHealth Science Advisory Board, Merrimack College Andrew Cannon, MHS, PT, SCS Dir., Sports Medicine, NRHN Team PT, Lecturer, Merrimack College
Critical consumers of dogmaticapproach to lumbar spine care and exercise Disc location
Trunk Performance No such thing as truly functional exercise Function is context and individual specific GPP, SPP Input versus outcome? Motor skill in, stability out! Ankle sprain, MDI Like the trunk, ROM is poor indicator of overall ability
Shoulder any different?Phases of Rehabilitation for Shoulder InstabilityPhase I Rest and immobilization Pain control with nonsteroidal anti-inflammatory drugs and ice applied to the shoulderPhase II Isometric strengthening Isotonic strengthening Begin exercises with shoulder in adducted, forward- flexed position, progressing to abducted positionPhase III Endurance building along with strengthening exercises Goal: the patient reaches 90% strength in the injured shoulder compared with the uninjured shoulderPhase IV Increase activity to sport- or job-specific activities
What is best for people with acute low back pain with or without radicular symptoms to do?
Bed rest for acute low-back pain and sciatica People with acute low-back pain who are advised to rest in bed have more pain and are less able to perform every day activities, on average, than those who are advised to stay active. As many people get some relief from low back pain and sciatica (pain down the back and leg) by lying down, bed rest is often recommended. However, this review found that, for people with acute low-back pain, advice to rest in bed is less effective in reducing pain and improving an individuals ability to perform every day activities than advice to stay active. For people with sciatica, there were no important differences in the effects of advice to stay in bed compared with advice to stay active. Page 106Hagen KB, Hilde G, Jamtvedt G, Winnem M. Bed rest for acute low-back pain and sciatica. Cochrane Database of Systematic Reviews 2004, Issue 4. Art. No.: CD001254
Williams flexion exercisesI have not been able to find one shredof evidence that they are better thanany other form of exercise or thatspecifically they are indicated over othertherapeutic exercise interventions
Evidence says pre-exercise does not Not pre-exercise 3x day does – 20 seconds, 5-7 reps, comfortable – Frequency is key – Limited value in spine care relative to spine stretching
Finally, separate out what is indicated to do what seems good to do, “clinical wisdom” what other people do what the patient wants to do what you have time to do what their parents/employer want them to do What the insurer will pay you to do
What patient is this new path for? Acute? No. Sub acute and beyond, Episodic Can they be radicular? Yes!, non progressive, stable, neurologically improving, weakness decreasing, reflexes increasing Change from victim to patient Pain versus function
Neuromuscular Function in Athletes Following Recovery From a Recent Acute Low Back Injury, Cholewicki et al, jospt vol. 32 #11, 11:2002 Chronic LBP, delay in shut off of agonist , switch on antagonist with fewer # of trunk muscles responding Varsity athletes with hx 1 episode of LBP, >6 months prior @injury pain 4.4/10, FVAS 30/100, min. 3 days OOP @testing, avg. 56 days post, pain 0/10, full participation A shutting off of a fewer number of agonists with an increased latency as well compared to matched controls
Stability Synergistic coordination of neuromuscular system to provide a stable base for superimposed functional movement or activity Shoulder MDI and hand placement But, the trunk??
What Do We Know About Lumbar Spine Segmental Instability? Clinical instability is a sagittal plane translation of > 3mm or 9% of vertebral body width on either an flexion or extension radiograph, and/or sagittal plane rotation >9 degrees for lumbar motion segments Clinical instability is a deficit in the end of range passive restraints Functional instability is a decrease in the capacity of the stabilizing system of the spine to maintain the spinal neutral zones within physiological limits so that there is no neurological deficit, no major deformity and no incapacitating pain Functional instability is a failure of the neural and contractile units to guide normal segmental motion within the neutral zone.
Cause or Effect?? Functional instability can be both the cause of and the result of injury Not just tissue based Motor control aspects – Coordinated contraction stiffens the joints and ultimately determines functional (in)-stability
How much load/shear is too much? Shear tolerance of vertebral motion segment of 2000-2800N one time loading Repetitive shear loads may be more likely 500N The osteoligamnetous spine buckles at 20N! How do muscles that compress make the spine more functionally stable? Luca d e al. Stability of the ligamentous spine. Technical Report #40, Biomechanics Laboratory, San Francisco, University of California
So what is stability from a spine perspective? Potential energy = PE= mass x gravity x height Stable equilibrium prevails when the PE of the system is minimum A ball in a bowl is stable. At the bottom of the bowl it is at minimum potential energy The deeper the bowl, the steeper the sides the more stable the system Bergmark A (1989) Stability of the lumbar spine: A study in mechanical engineering. Acta Orthop. Scand 1989; 60:3-53.2
The Continuum of Stability Slope of sides = stiffness of passive tissues = mechanical stop/end point Width of the bottom of the bowl = joint laxity Bergmark A (1987) Mechanical stability of the human lumbar spine. Doctoral dissertation, Department of Solid Mechanics, Lund University, Sweden
how many sides does the bowl need? Spinal joints can rotate in 3 planes, along 3 axes Requires a 6 dimensional bowl for each 6 lumbar spinal joints = 36-dimensional bowl If the height of the bowl is decreased in any one of these 36 dimensions, the ball rolls out! A single muscle having inappropriate force or a damaged passive tissue can cause instability
Potential energy as stiffness and storage of elastic energy. stiffness = (k) deformation = (x) so stretching a band with stiffness x a distance x will store energy (PE)
Elastic PE = .5 * k * x Stretching a band with stiffness (k) a distance (x) with store energy (PE) Increase in k = increase in side of the bowl Stiffness creates stability to support larger loads (P) Most important is stiffness is balanced Increased stiffness of just 1 spring will lower PE in one direction and decrease ability to bear load
Symmetrical Stiffness Active muscles act like a stiff spring Modest levels of muscle activation create sufficient stiff and stable joints Motor control system modulates stiffness therefore stability through coordinated muscle co- activation
How Much Stability is Enough ? What is Sufficient? Too much stiffness and muscle coactivation imposes a load penalty/prevents motion Muscular stiffness necessary for stability with a modest extra for margin of safety How hard do the muscles need to work to provide adequate stability in the neutral zone? 5%-20% MVC with ADL to athletic activities Strength or endurance? Remember the bowl needs all its sides!!
Is a single muscle most important Inappropriate application of “Queensland” research, did not say tva and mf “more” important Was any single string more important? All muscles play a role in stability, roles vary based on task at hand and resources available
You need a strongtrunk to protect your back 10% of MVC abdominal wall cocontraction Endurance over strength Proper daily motion is “endurance training”
What are stabilization exercises An exercise repeated in a way that grooves motor patterns and ensures a stable spine Consider loading as to how good an exercise is An athlete requires a stable spine during c-v demanding, complex motor skill. It is not whole body stability, balance
What is the most important muscle Which wire is most important to the tower standing How can wires/muscles that add compression, decrease compression?
Upper and lower rectus There is no functional separation of the rectus abdominis Is a separation of neural drive, rarely! Once activated, function as a cable throughout its length If you mean, lower abs, could be TVA, that would be the lateral ‘V’
We give patients lumbar stability exercises Input or output? We train motor skill They get stability