Download Pathophysiology of Spinal Stenosis

Francis P. Lagattuta, M.D.
Santa Maria, Santa Barbara,
Lompoc, Atascadero
California
Pathophysiology
of
Spinal Stenosis
Classification of Spinal Stenosis
Classification of Spinal Stenosis
LAGS Spine & Sportscare
Congenital Stenosis
(Developmental)
•Idiopathic
•Achondroplastic
Central Stenosis
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•
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Ligamentum flavum buckling
Ligamentum flavum hypertrophy
Disc protrusion
Hypertrophic zygapophyseal joints
Degenerative spondylolisthesis
Acquired Stenosis
•Degenerative (most common type)
•Combined congenital and degenerative
stenosis
•Spondylitic/spondylolisthetic
•Iatrogenic (ie, postlaminectomy,
postfusion)
•Posttraumatic
•Metabolic (ie, Paget’s disease, fluorosis)
Ligamentum flavum changes
1. Proliferation of fibrocortilage
collagen type II
2. Ossification
3. Calcium crystal deposition
Lateral Stenosis
• Entrance zone
• Mid zone
• Exit zone
Entrance Zone Stenosis
Cause
• Hypertrophic osteoarthritis of Z-joints
• Posterior disc herniation
Midzone Stenosis
Cause
• Defect of pars interarticularis
(spur under pars at attachment of
Ligamentum flavum)
• Pedicular kinking
• Lateral disc protrusion
• LSS, spondylolisthesis
Lateral Zone Stenosis
Cause
• Hypertrophic osteoarthritic changes in Zjoints
Blood Supply of the Nerve Roots
• Lumbar (Segmental) arteries
- arise from aorta in 5 pairs
Lumbar Arteries terminate in
3 branches
•Anterior spinal branch
•Posterior spinal branch
•Radicular branch
Lumbar Veins
• Accompany lumbar arteries
• Drain
Anteriorly – inferior vena cava
Posteriorly – ascending lumbar vein
Nerve Root Blood Supply
• Radicular Branch
• Proximal radicular arteries from
intrinsic spinal cord arteries
• Anastomose in proximal half of
nerve root
Basivertebral Veins
• Receive blood from vertebral body blood
supply into anterior internal vertebral
venous plexus
Primitive Valve
between radicular veins and plexus
•Prevents blood drainage and plexus
engorgement
HTN, exercise, space occupying
lesions
Venous Engorgement Theory
venous dilation
•Increased epidural and intrathecal
pressure
•Microcirculatory neuroischemia
ensues
Radicular Veins (nerve roots)
• Drain into lumbar veins or anterior internal
vertebral venous plexus
Radicular vein congestion
• Pressure elevation
• Potential nerve root ischemia
Porter, Baker etc.
• Two levels of stenosis needed–
either central or lateral to increase pressures
Reference
Kauppila L.I. “Atherosclerosis and disc
degeneration/low-back pain—a systematic
review.” Eur J Vasc Endovasc Surg. 2009 Jun;
37(6): 661-70. Epub 2009 Mar 27.
http://www.ncbi.nlm.nih.gov/pubmed
Biomechanical factors
• Extension of spine
-raises spinal epidural pressure above
venous system.
• Rotation
-theoretically the same
• Flexin
-reduces spinal epidural pressure
Arterial Insufficiency Theory
• Abnormal dilitation with lower limb
exercise
Baker et al.
• Normal – Blood flow increase – 252%
• Site of compress – Blood flow decrease –
26%
• Peripheral muscle activity decreased
Prostaglandin E Derivative
Increases Blood Flow
• Fukusaki M., Miyako M., Miyoshi H., Takada M., Terao Y.,
Konishi H., Sumikawa K. “Prostaglandin E1 but not
corticosteroid increases nerve root blood flow velocity after
lumbar diskectomy in surgical patients.” J Neurosurg
Anesthesiol. 2003 April; 15(2): 76-8.
http://www.ncbi.nlm.nih.gov/pubmed
• Shirasaka M., Takayama B., Sekiguchi M., Konno S.,
Kikuchi S. “Vasodilative effects of prostaglandin E1 derivate
on arteries of nerve roots in a canine model of a chronically
compressed cauda equina.” BMC Musculoskeletal Disord.
2008 Apr 8; 9-4. http://www.ncbi.nlm.nih.gov/pubmed
Inflammatory Cascade
Biochemical Medications Cause Pain
•
•
•
•
Phospholipase A2
Cytokines
Nitric Oxide
Proteoglycans
Inflammation
• Increased neural sensitivity to minor
mechanical compression
Classification of Lumbar Spinal
Stenosis
Cortico Steroids
• Cortico Steroids in animal studies showed
decreased levels of inflammatory mediators
Instability of Spine
• “stretch” neuritis
Constitutional Stenosis
Effects
interverbal
space
narrowing on
foraminal
dimensions on
dried vertebrae
Severe Degenerative
Spondylolisthesis of L5 and mild
slipping of L4
Algorithm for treatment of
simple stenosis
Simple
Degenerative
Stenosis
Lateral stenosis due to a synovial
cyst of the left facet joint at L4-5
level
Algorithm for treatment of
degenerative spondylolisthesis
Central Stenosis
Functional radiographs demonstrate
hypermobility of the olisthetic
vertebra
Central stenosis in a patient with degenerative spondylolisthesis at L4-5. Preoperative
radiograph and MRI scans during degenerative olisthesis and stenosis.
Radiographs taken after total
laminectomy, bilateral pedicle screw
instrumentation, and PLIF at L4-5 level
Electromyography (EMG) and
Nerve Conduction Studies (NCS)
• Nerve and muscle cells generate electrical
activity with muscle recruitment and in
pathological states
• Nerve conduction studies can evaluate the
speed of the conduction within a nerve and
if axons and muscle cells are functioning
appropriately.
Electromyography and Nerve
Conduction Studies
Electromyography and Nerve
Conduction Studies
• EMG needle studies can assist with
evaluation of certain types of nerve/muscle
pathology and acuity of injury
• Needle electrode is inserted into muscles
• Can assess if nerve damage is from spine
versus peripheral nerve (e.g., peroneal
neuropathy)
• Can assess for acuity of nerve damage
• Can assess other causes of weakness: ALS,
myopathy
When to use
• When other tests are not diagnostic in patient with
neurologic signs/symptoms
• New or worsening neuropathic pain in limb with
previous neurologic injuries
• Identify root level when imaging is non-diagnostic
and injection or other procedure is being
considered
• When multiple diagnoses are present, to assist
with primary problem (radiculopathy in post-polio
patient)
Nerve Conduction Velocity
• Prolonged H wave
• Prolonged F wave
• Decreased Amplitude – motor sensory
studies
Mechanisms of Radicular Pain
• Mechanical compression
• Inflammation
• Ischemia
Abnormal EMG findings
• Membrane irritability
• Decreased Neuropathic motor units
Reference
Wallbom A.S., Geisser M.E., Haig A.J., Koch J.,
Guido C. “Alterations of F wave parameters after
exercise in symptomatic lumbar spinal stenosis”
Am J Phys Med Rehabil. 2008 Apr; 87(4): 270-4.
http://www.ncbi.nlm.nih.gov/pubmed
Is It Simply Mechanical
Compression?
• Animal studies show isolated mechanical
compression of a nerve root does not induce
radicular pain
• Asymptomatic individuals have HNPs
• Size of HNP does not always correlate with
degree of pain
• Improvement of pain is seen prior to disc
resorption
INFLAMMATION
ISCHEMIA
• Inflammatory mediators have been found in
various histologic studies
• Has been particularly implicated in stenotic
patients
• Often have claudicatory nature to their
radicular pain
•
•
•
•
•
•
•
•
PLA-2
Prostaglandins
Cytokines
NO
Macrophages
Immune system mediators
Substance P
And many more
Gabapentin
Yaksi A., Ozgonenel L., Ozgonenel B. “The
efficiency of gabapentin therapy in patients with
lumbar stenosis” Spine 2007 Apr.20 ;32(9):939-42.
http://www.ncbi.nlm.nih.gov/pubmed
NSAIDS
• One a day dosing
• Cardiovascular risk factors
Analgesics
•
•
•
•
•
Opioids
Shorting acting
Long acting
Tramadol
Short and long acting
Limaprost (New Treatment)
• Matsudaira K, Seichi A, Kunogi J,
Yamazaki T, Kobayashi A, Anamizu Y,
Kishimoto J, Hoshi K, Takeshita K,
Nakamura K. “The efficacy of
prostaglandin E1 derivative in patients with
lumbar spinal stenosis.” Spine(Phila Pa
1976). 2009 Jan 15;34(2):115-20.
http://www.ncbi.nlm.nih.gov/pubmed
MECHANISM OF EFFECT OF
ESIs
• Anti-inflammatory
• Anti-nocioception
-Block C-fiber transmission (Siddall, Spine 1997)
• Supress immune response
• Mechanical debridement
-“washing away” of inflammatory mediators
• Stop “pain-spasm” cycle
• Placebo effect
Transforaminal vs. Interlaminar
Lumbar
• Interlaminar ESI
– Drug delivered in posterior epidural space with diffuse
spread expected
– No high quality studies that demonstrate efficacy
• Transforaminal ESI
– Drug is delivered in maximum concentrations, closer if
not directly to the site of pathology
– Comparison studies favor TFESI efficacy over
interlaminar
– Case reports of cord infarct/ paraplegia related to
possible injection into medullary artery
Transforaminal ESI Efficacy
Transforaminal ESI Efficacy
• (Wiener 1997) 30 patients with radicular pain who
had failed conservative care and were considering
surgery
– 6 of 30 patients went on to surgery
– 2 patients were lost to follow-up but had reported
complete relief of their pain at 6 weeks after injection
– 14 had complete relief of pain at an average follow-up
of three years
• 46% success rate in achieving complete relief of
pain
Postoperative radiographs
Lumbar
• (Riew 2000, 2006) RCT steroid vs. LA alone
– Surgical pts with radicular pain
– Significantly less (29%) pts rx’d with steroid+LA required surgery
than LA alone (67%)
– Transforaminal injections of corticosteroids may be a surgerysparing intervention
• (Lutz 1998) TFI for HNP
– 75% greater than 50% decrease in pain at 28-144 wks follow up
• (Botwin 2002) TFI spinal stenosis
– 75% with improved pain, 64% with improved walking/standing
tolerance, 1yr follow up
Postoperative radiographs taken 4 years after total laminectomy and bilateral pedicle screw
instrumentation and intertransverse fusion at L4-5 in patient with degenerative
spondylolisthesis and stenosis.
Fluoroscopic Guidance
• Aspiration fails to
produce flashback of
blood in up to 74% of
documented
intravascular injection
(Sullivan et al, Spine 2000)
• Incidence of
intravascular injection
approx 8.5%
Evidence based relief from PT
and Epidurals
Epidurals
• Procedure: Injection of
diagnostic or therapeutic
substance including
anesthetic, antispasmodic,
opioid, steroid, other solution.
• Indications: Radiculopathy,
Disc Herniations, Stenosis
• Contraindications: Surgery,
bleeding disorder, altered
anatomy.
• Complications: Bleeding,
infection, nerve root injury,
cord injury.
Lumbar/Sacral TFEs
Koc Z., Ozcakir S., Sivrioglu K., Gurbet A., Kucukoglu S.
“Effectiveness of physical therapy and epidural steroid
injections in lumbar spinal stenosis. “ Spine 2009 May 1; 34
(10): 985-9. http://www.ncbi.nlm.nih.gov/pubmed
Caudal Epidural
Facet Joint Injections/Medial Branch
Blocks
• Procedure: Injection
anesthetic and/or steroid,
paravertebral facet joint or
facet joint nerve.
• Indications: Axial spine pain.
• Contraindications: Surgery,
bleeding disorder, altered
anatomy.
• Complications: Bleeding,
infection, nerve root injury,
cord injury.
Evidence based for surgery
Weinstein J.N., Tosteton T.D., Lurie J.D., Tosteton
A.N., Blood E., Hanscom B., Herkowitz H., Cammisa
F., Albert T., Boden S.D., Hilibrand A., Goldberg H.,
Berven S., An H., SPORT Investigators. “Surgical
versus nonsurgical therapy for lumbar spinal
stenosis.” N Engl J Med. 2008 Feb 21; 358(8):794810 http://www.ncbi.nlm.nih.gov/pubmed
Rehabilitation Approach
• The site of symptom is often the “Victim”
– Often the KNEE in the LE CKC
• The “Culprits” are often restrictions or
uncontrolled mobility at other sites
– HIP
– FOOT
– TRUNK/CORE
Basics of CKC
• We function in 3 dimensions:
– Sagittal Plane
– Transverse Plane
– Frontal Plane
• Interrelationship of parts.
• Negative feedback cycle when things go
wrong.
Treat the Culprits…
• 1. Provide exercises that progressively load restricted
tissue to allow for tissue adaptation and challenge
functionally uncontrolled motions found during
assessment.
• 2. Work with your successes – may need to start in
planes that the injured tissue is involved but not
dominant
• 3. Mat exercises may be where we start
treatment…probably not the best place to end
treatment
• 4. Flexibility needs to be addressed in multiple planes.
• 5. Patients need to control mobility.
Benefits of CKC functional
exercise
• Targets specific “culprits” interfering with
biomechanics of the kinetic chain
• They did this to themselves, they can undo it too!
Allows for safe progression of exercise.
• Re-enforces / Maintains mobility gains when
manual mobilization is indicated
• Provides co-contraction of force couples and early
activation of muscles in their physiologic positions
• Promotes balance/ proprioception retraining.
• Gives them control and confidence!
Evidence based for Physical
Therapy
Whitman, J.M., Flynn T.W., Childs J.D., Wainner
R.S., Gill H.E., Ryder M.G., Garber M.B., Bennett
A.C., Fritz J.M. “A comparison between two physical
therapy treatment programs for patient with lumbar
spinal stenosis: a randomized clinical trial.” Spine
2006 Oct 15; 31 (22): 2541-9
http://www.ncbi.nlm.nih.gov/pubmed/107047542
General Exercise Progression
Parameters
• Submaximal effort to maximal effort
• Isometric to Eccentric
• May start anywhere but always end with
functional activity
• Small ROM to larger ROM
• Stable surface to unstable
• Less functional to functional?…
Goals of Rehabilitation
• TREAT PAIN!
• RESTORE FUNCTION!
Exercise Progression
Early Acute Management: Inflammatory
Stage (Chemical)
• 0-5 days in general. Re-assess each visit.
• Pain is your guide.
• Decrease the inflammation and protect the
injured area.
• Looking for the movement that helps
localize/centralize pain.
Exercise Progression
• Late Acute / Early Sub-acute Management
Proliferation Stage (In between Inflammatory and
Ischemic)
• Day 5-14 in general. Re-assess each visit.
• Weak scar tissue.
• Restore full ROM, but do not load tissue at endrange.
• Looking for the motion that helps to localize/
centralize pain.
Today’s Lab – How you may
tweak
• Facilitation Cues - encouraging a motion or
biomechanical pattern to occur
• Inhibition Cues – tweaking the exercise to
discourage an “error”
• Working with relative motion – start where
they can be successful
3 Plane Core
• Sagittal Core (SP)
• Frontal Core (FP)
• Transverse Core (TP)
Exercise Progression
• Late Subacute / Return to activity Remodeling
Stage (Ischemic)
• Day 14+
• Pain is progressively less of a guide to becoming
the goal
• “No worse”
• Work the stabilizers, move the restricted tissue.
• Counteract gravity working in
balance/proprioception
• All plains- TWEAK AWAY with weights, speed,
duration, range of activity.
Lunges
• In order of ease
–
–
–
–
Lateral
Rotational
Backward
Forward
• Primarily working
– Hip and Knee Link
– Eccentric/ Concentric Gluts, Hams, Quads, Adductors,
Abductors
Tweaking the lunges
• Tweak in Hips
– Reaches facilitate turning hip on:
• Forward – Flexion
• Toward Lunging Leg - Internal Rotation /
Adduction
• Tweak Out Hips
– Reaches facilitate turning on knee and ankle:
• Overhead – Extension
• Away from Lunging Leg – External Rotation /
Abduction
• 1 hand vs. 2 hand reach
Step Down Training
• Primarily working
– Ankle and Rear Foot mobility
– Eccentric Control of Quadriceps, Gastrocsoleus
• In order of ease:
– Posterior
– Medial
– Anterior
• May need and UE reach tweak?