- Lumbar spinal stenosis involves a narrowing of the spinal canal which causes compression of the nerves and blood vessels in the lower back. It is a common condition in aging individuals that results from degenerative changes in the spine over time. - Patients with lumbar spinal stenosis often present with leg pain that takes the form of neurogenic claudication or radicular pain, as well as low back pain. Symptoms are typically exacerbated by standing and walking and relieved by sitting or flexion of the spine. - MRI is the preferred imaging modality for evaluating lumbar spinal stenosis. While findings on imaging are common in asymptomatic older adults, clinical correlation is important. Conservative treatment is usually tried initially and surgery is considered if symptoms

1. Lumbar Spinal Stenosis
Dr.Ponnilavan

2. Introduction
• Spinal stenosis :
- stenosis - Greek word -stenos - narrow,
- spinal canal narrowing.
- First described by Antoine Portal in 1803.

3. Verbiest – coined - term spinal
stenosis & the asso.narrowing of
spinal canal as its potential
cause.
Verbiest et al
- relative spinal stenosis - dia b/w 10 & 12
mm
- absolute stenosis – dia < 10 mm

4. • In 1970 , Kirkaldy Willis described the degenerative cascade in
the lumbar spine as the cause for the altered anatomy &
pathophysiology in spinal stenosis.

5. Anatomy
Trefoil canal - smallest
CSA.
• present in 15% of
individuals &
predisposes these
individuals to lateral
recess stenosis.

6. Anatomical classification
• on the basis of the location of neural compression.
- central,
- lateral recess,
- foraminal

7. Central canal stenosis
• With aging, occurs as degenerative
changes progress.
• As the axial ht of disc & facet jts
decreases, disc bulges into spinal canal.
• Central canal is further narrowed by
posterior impingement from enlarged
facets & hypertrophied ligamentum
Flavum

8. • Hypertrophy of the soft tissues is responsible for 40% of spinal
stenosis
• With extension, the hypertrophied ligamentum buckles centrally into
the canal and worsens the central stenosis.
• This explains why patients with stenosis typically report worsening of
their symptoms in extension.

9. Lateral recess stenosis
• typically results from posterior disc protrusion in combination with
some superior articular facet hypertrophy.
• Lateral recess stenosis can present with lumbar radiculopathy;
incidence of lateral recess stenosis ranges from 8% to 11%.

10. Foraminal stenosis
• causes compression of the exiting nerve root and ganglion and leads
to lumbar radiculopathy.
• occurs most commonly in the lower lumbar spine, with the L5 nerve
root being the most commonly involved.
• can occur from loss of disc height, vertebral endplate osteophytes,
facet osteophytes, spondylolisthesis, and disc herniations

11. Lee et al. classification
• Nerve root canal into three zones to clarify the anatomy and to
describe the pathologic structures responsible for nerve root
compression within the three zones:
• lateral recess,
• foraminal,
• and extraforaminal stenosis

13. Etiological
Classification

14. Pathophysiology
Schonstorm evaluated the changes in nerve pressure
that occur as the spinal canal narrows.
In his human cadaver study, thecal sac constriction of
> 45% led to an increased pressure in the nerve roots.
As the degree of compression increased, the pressure
in the nerve roots increased.

15. Delamarter & colleagues also demonstrated the
importance of the magnitude of thecal sac compression in
alteration of neural function.
They noted no alteration in neurologic function when the
animal’s cauda equina was constricted by 25%, whereas
more than 50% compression led to motor or sensory
deficits

16. • Pedowitz & colleagues demonstrated that the duration of
compression was also an important factor in neural
dysfunction.

17. • Rydevik & colleagues demonstrated another effect of compression of
thecal sac.
• Pressure > 50 mm Hg caused capillary restriction & electrophysiologic
alteration in nerve roots.
• Solute transport decreased 45% across nerve root segments with the
low pressure of 10 mm Hg.
• 5 to 10 mm Hg- venous congestion of intraneural microcirculation
occurred.
• This suggests that low-grade sustained compression of the nerve roots
could lead to vascular impairment & potential detrimental changes in
nerve roots fn.
• In addition to neural compression & altered nutrition, inflammatory
chemical mediators also shown to cause pain.

18. Clinical Presentation
Patients with lumbar spinal stenosis most commonly present
with leg pain.
leg pain presents as either neurogenic claudication or
radicular leg pain.
Patients with NC report a feeling of pain, heaviness,
numbness, cramping, burning, or weakness.
Symptoms typically start from the back or buttocks &
bilaterally radiate down below the knees.

19. • Symptoms usually do not follow a dermatomal pattern and are
usually related to activities.
• These abnormal sensations are typically worse with extension of the
lumbar spine during walking or standing for a prolonged time

20. • Some report worsening weakness if they keep walking.
• They may note ankle dorsiflexion weakness that is typically described
as feet slapping or even falling as they attempt to keep walking.
• Walking downhill is more challenging for these patients as the lumbar
spine is extended while going downhill
• Most describe a set distance they can walk before the symptoms
become disabling.

22. As the stenosis worsens, this distance typically decreases,
further disrupting the daily life and function of these
patients.
- Relief of symptoms typically comes from flexing the
lumbar spine by leaning forward, sitting, or lying down.

23. Degree of stenosis decreases as lumbar spine is flexed & pts
naturally learn to position themselves in a posture that
minimizes discomfort & maximizes fn.
- Keeping this in mind, it is easy to understand why these pts
typically lean forward on a grocery cart & have an easier time
riding a bike, walking uphill, or driving while sitting in a car.

24. In contrast to neurogenic claudication arising from compression
of thecal sac, radicular pain arises from compression of a
particular nerve root in the lateral recess or neural foramen.
Unlike claudication, radicular leg pain is described by pts in a
specific dermatomal pattern corresponding to the compressed
nerve root.

25. • Low back pain is also a common complaint in pts with stenosis.
Although most patients note the radiation of this pain into their legs,
some present without leg pain or note radiation of the pain only into
their buttocks.
• Severe neurologic symptoms, such as bowel & bladder incontinence or
profound weakness, are uncommon in patients with stenosis.

26. Physical Examination
• A good physical examination of patients with lumbar spinal stenosis
should start with observation.
• Often, these pts will be sitting flexed forward on a chair in the
examination room.
• While standing & ambulating, stenosis patients still often flex their
trunk forward to decrease their symptoms.
• ROM shows decrease in the active lumbar extension.

27. • Reproduction of the pt’s usual symptoms by prolonged lumbar
extension can also be helpful in confirming the diagnosis.
• Neurologic examination is often normal in spite of long-standing
debilitating symptoms.
• Lateral recess stenosis is more commonly responsible for neurologic
changes.
• When motor weakness or sensory deficit is present, it is most often
in the L5 distribution.

28. • A frequent neurologic finding is an asymmetrical deep tendon reflex at the
patellar or Achilles tendon.
• A symmetrical decrease in the reflexes is more indicative of age-related
changes.
• Nerve root tension signs are usually not present
• Changes in neurologic examination may become more obvious after
stressing the patient’s neurologic system.
• This can be accomplished by asking the patient to walk until Pt experiences
significant symptoms.
• Reexamination at this point may reveal changes in motor, sensory, or reflex
examination that were not detected before the stress.

29. • Amundsen & colleagues prospectively evaluated the clinical and
radiographic features of 100 patients with symptomatic spinal
stenosis.
- They reported a motor weakness in 23% and sensory deficit in 51%.

30. • In the 2007 randomized controlled trial of 94 stenosis patients from
the Finnish Lumbar Spinal Research Group,
• 22% of patients had an L5 motor weakness and 19% had a sensory
deficit.
• SLRT was positive in 3% of the patients.

31. • In the recent SPORT study,
• asymmetrical reflexes were noted in 26%,
• motor weakness was noted in 28%,
• and sensory deficit was noted in 29%.

32. • Diagnostic testing of patients with spinal stenosis often starts with
plain radiographs.
• In addition to the AP & lateral radiographs, flexion & extension lateral
views should be obtained.

33. • Prior to the common availability of MRI, a CT scan was the study of
choice for visualizing pathologic anatomy in the axial plane. Because a
significant portion of the stenosis comes from soft tissue pathology,
visualization of the soft tissues is the top priority in axial imaging.

34. A CT scan is a poor modality
for detailed analysis of the
soft tissue pathology.
A metaanalysis demonstrate
that the sensitivity of a CT
scan in detecting spinal
stenosis ranges from 70% to
100%.
Soft tissue window of a computed tomography scan through
the L4–L5 level demonstrating stenosis

35. • Diagnostic utility of the CT scan can be improved by combining it with
myelography
• Dye injected in CSF during a myelogram provides good contrast b/w
thecal sac & surrounding soft tissue and bony pathology.
• Preoperative complete contrast block on a CT-myelogram has been
correlated with an improved surgical outcome.
• Invasiveness of the myelogram and the radiation associated with the
CT are the two biggest drawbacks of this diagnostic modality

36. • Given these limitations,
patients who are unable to
have an MRI, who have
scoliosis, or who have previous
spinal instrumentation are the
most likely to undergo this
study.
Myelogram of a pt with neurogenic claudication who had a
h/o a previous lumbar instrumented fusion.

37. • MRI is the diagnostic modality of choice in patients with suspected
lumbar spinal stenosis

40. • Boden et al. noted abnormal findings in 67% of asymptomatic
patients evaluated by MRI.
• In patients older than 60 years, 57% of MRI scans were abnormal,
including 36% of patients with herniated nucleus pulposus, and 21%
with spinal stenosis.
• Hence, findings of MRI should be matched with the symptoms and
signs of patients having neurogenic claudication or radiculopathy.

41. • Electromyography (EMG),
• nerve conduction studies (NCSs), &
• somatosensory evoked potentials (SSEPs) are not part of the routine
workup of patients with spinal stenosis.

42. Differential diagnosis
• Vascular claudication
• lumbar spondylosis,
• lower extremity arthritis,
• cord compression,
• neurologic disorders,
• peripheral neuropathy,
• infection,
• tumors, and
• lumbosacral plexus lesions.

43. SUMMARY
• Lumbar disc degeneration is a nearly universal finding in aging
population.
• Lumbar stenosis does not progress rapidly and catastrophic
neurologic deterioration is rare. Therefore, a trial of nonoperative
management is indicated in most cases.
- Patients with symptomatic stenosis may present with one or more
of a combination of axial pain, radiculopathy, and neurogenic
claudication. Each of these is associated with different historical and
examination findings.
• Patients with lumbar stenosis often have other coexisting
pathologies—such as hip or knee arthritis, vascular claudication,&
cervical myelopathy—that may confuse the clinical picture.

44. • What causes pain in some individuals with mild spinal stenosis and no
symptoms in others with severe stenosis?
The experimental evidence reviewed earlier suggests that each
individual may have an innate ability to compensate for the
accumulating pathologic changes.
Because the magnitude an individual can compensate for is different for
different people, two individuals with thesame amount of stenosis may
not exhibit the same symptoms.
The rate at which these changes are occurring also appears to be
important. Individuals may become symptomatic with a lower
magnitude of compression if it occurs rapidly.
This explains how a patient with stenosis can become symptomatic
with an acute mild disc herniation.

45. THANK U