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Spondylolisthesis is the
term applied to a condition where one Vertebral Body
has "slipped" forward relative to the adjacent Vertebral
Body. Spondylolisthesis can be a significant causative
factor in the Spinal Stenosis mechanism responsible
for the symptoms in some patients. This is reviewed in detail
in the next major Section following this one.
Part of the initial evaluation of a patient with Spinal
Stenosis requires a
Focused Neurological Examination including the evaluation of the Peripheral Arteries supplying the Lower Extremities.
There are some other examinations which can be obtained to
evaluate these arteries (such as Ultrasound and
Angiography); however, they are much more expensive
and unnecessary for every patient.
Although plain x-rays of the Lumbar Spine allow for the
evaluation of some aspects of the Spine's bone
structure, they are of limited value since they
cannot identify the presence or absence of a
Herniated Disc, Synovial Cyst, Hypertrophic Ligamentum Flavum
or the degree of Stenosis.
MRI (Magnetic Resonance Imaging) scan is a non-x-ray
technique that is often used as the first (or screening)
Neuroimaging study in many patients. While it has some
limited usefulness in evaluating bone anatomy, it is an
excellent technique for evaluating the Spinal Canal, Disc
anatomy, the Nerve Roots and the Spinal Cord (which is
rarely involved by Lumbar region pathology since the Spinal
Cord "ends" near the T12-L1 level). Oftentimes this is the only
Neuroimaging method that we will need. It is also an
excellent technology for evaluating tumors (almost
always benign) within the Spinal Canal. MRI scanning
is also very useful in evaluating the Thoraco-lumbar junction
of the Spine. The Thoracic area of the Spine lies just above
the Lumbar region and is a frequent location for
advanced Degenerative Disease and
Herniated Thoracic Disc
in older people.
A CT or CAT (Computerized Axial Tomography) scan is an
x-ray examination that is particularly useful for evaluating
bone anatomy (including the Facet Joints) of the Spinal Column and
(to a lesser extent) the Disc structures. CT Scanning is
not part of a routine evaluation of the Spine nor is it often
used for "screening" purposes. CT Scanning is vitally important
when combined with Myelography.
"MYELOGRAPHY" (See Figure 3) coupled with
"POST-MYLEOGRAPHIC CT SCANNING" (See Figures 4, 6A, 11A & 11B)
is regarded as the "gold standard" Neuroimaging method for
evaluating Spine problems. This procedure involves
placing a long needle in the patient's lower Lumbar region,
through the Dura Mater and into the "Subarachnoid Space"
in order to gain access to the Cerebrospinal Fluid (CSF).
A water-soluble "Dye" substance is injected through the needle
into the CSF which then circulates around the Nerve roots and is
"visible" on x-ray.
However, this is an "invasive procedure" that we reserve
for patients where the MRI Scan has failed to provide adequate
information and only when these patients are operative candidates.
It is not to be considered as part of a routine evaluation for
Spine patients nor is it required for all patients who are to
undergo Spinal operative intervention. The specific indications
for this procedure are reviewed in our Monograph
PART 2 of this Patient Information Series.
Other investigation methods such as bone scanning, bone density
testing and PET (Positron Emission Tomography) are
generally not required for patients with new
onset of symptoms unless that routine testing (such as
reviewed in the preceding paragraphs of this document) fails
to establish the diagnosis or some additional problem is identified
that requires further elucidation (such as a tumor
involving the Vertebral Bone).
Steroids cannot affect the Bone, Facet Joint, Disc or Ligament
conditions that are part of this complex condition. Steroids can
reduce the swelling of the Nerve Roots that may have
occurred as a result of some acute change. Nevertheless,
placing a catheter into an already compromised Spinal Canal
in the presence of swollen and damaged Nerve Roots is actually
placing those Nerve Roots at more risk. A better
alternative to manage the ACUTE NERVE ROOT SWELLING, in our
opinion, is to use ORAL STEROIDS which, in adequate dosage,
will be just as effective and far less dangerous with
considerably less cost.
All surgical therapies designed to relieve the compression of
the Neural elements (Nerve Roots and/or Spinal Cord) caused
by LUMBAR SPINAL STENOSIS usually require the removal of
those portions of the Spine that are causing the
problem. The most frequent operations performed for these
diseases involve an avenue of approach from the back
(posterior). All of these techniques involve the
removal of part or all the "roof" of the Spinal Canal in the
affected area. The "roof" of the Spinal Canal is
formed by the Lamina of the Vertebra. Removal of the
Lamina ON BOTH SIDES is called a "LAMINECTOMY". Removal of
the Lamina ON ONLY ONE SIDE is called a
"HEMILAMINECTOMY."
There are some "limited" operations that are mainly
used for focal and restricted narrowing (with or without a
Herniated Disc.) The most common of these procedures
involves removing only a thumbnail-size piece of bone from the
Lamina in order to gain access to the Spinal Canal where
a Herniated Disc fragment is compressing the Nerve Root,
in patients with an isolated Synovial Cyst or in those
with a limited area of Ligamentum Flavum Hypertrophy.
This procedure is called a "LAMINOTOMY" (or opening
in the Lamina). The bony canal through which the Nerve
Root travels as it leaves the Spinal Canal is called the "Neural
Foramen". It is almost always desirable, and frequently
fundamentally necessary, to remove part of the roof of
this Foramen in order to decompress (relieve pressure on) the
Nerve Root. This procedure is called a "Foraminotomy."
Any of these procedures can be used in combination to suit the
unique technical requirements for any particular patient
circumstance.
In the event that a Bone Spur is the culprit causing
the Nerve Root compression, it may be possible to remove it.
This is usually the case if the Bone Spur originates
from the Facet Joint directly behind the Nerve Root.
However, if the Bone Spur projects from the front of the
Spinal Canal, it may not be possible to safely remove all or any of
the Spur. The "decompression" of the Spinal Canal and the affected
Neural Foramen is most frequently very successful in treating the
symptoms and signs of this problem. While it is quite evident
that when all or part of the Bone Spur remains in place, it
could continue to enlarge, it is actually UNLIKELY
TO CAUSE any further major difficulties provided an ADEQUATE
DECOMPRESSION HAS BEEN ACCOMPLISHED.
There are several modern surgical options available
to treat Spinal Stenosis. The most advanced method,
Minimally Invasive Microendoscopic Surgery
is available for many of these patients. These operations are
conducted through a short incision made just off the midline
to the side of the main problem. This newer technique differs from
the more traditional (and very effective) Microsurgical
Operation in that in Minimally Invasive Surgery the large
muscle fibres (that run vertically on the side of the Spinous
Process and Lamina) are SEPARATED (using a specially
designed small tubular retractor) rather than stripping
muscle from the bone of the Spine, as is done in the case of the
more traditional operation. In the more
traditional Microsurgical Approach, the muscle would be
removed from the bone of the Spine and then held firmly,
under considerable pressure, behind steel retractors. (See the
differences between the two procedures in Figure 9.)
In both cases, the Lamina (which forms the "roof" of
the Spinal Canal) must be removed in order to
gain access into the Spinal Canal and perform the
required "decompression" of the Nerve Roots which are
protected within a leather-like covering (the Dura Mater).
BILATERAL DECOMPRESSIVE LAMINECTOMY USING A UNILATERAL APPROACH
A Major Advance in Spine Surgery
It is now possible, in many patients, using
Minimally Invasive Microendoscopic
Surgery to actually perform the Laminectomy procedure
on BOTH sides (bilateral) of the Spine using a ONE-SIDED
(unilateral) APPROACH. This is a significant
advance since the post-operative pain is usually
much less than in our more traditional approach because we
are not stripping muscle from bone. Although this
technique is not always possible in all cases, MOST
SPINAL STENOSIS PATIENTS CAN BE MANAGED THIS WAY BY A NEUROSURGEON
EXPERIENCED IN THIS ADVANCED TECHNIQUE. The underlying anatomical
pathological causes of Spinal Stenosis (Hypertrophic Ligamentum
Flavum and Hypertrophic Lumbar Facets) can both be successfully
relieved using Minimally Invasive
procedures.
Bilateral Decompressive Laminectomy with Bilateral
Foramenotomies using a UNILATERAL APPROACH is a highly advanced and
technically demanding operation. Nevertheless, it constitutes
a major technical advance in the treatment of many
patients with Spinal Stenosis as a component of their
clinical problem. (This advanced procedure is also utilized for
the Minimally Invasive Microendoscopic management of certain Spinal Cord Tumors.)
Degenerative Osteoarthritis resulting in Spinal Stenosis
commonly occurs at MULTIPLE LUMBAR LEVELS in many of
these patients. Oftentimes a multi-level Decompressive
Laminectomy is required in order to adequately relieve the
severe stenosis.
Over the past years, we have demonstrated the feasibility to
routinely manage Multi-level Lumbar Spinal Stenosis using MINIMALLY
INVASIVE UNILATERAL Techniques by incorporating multiple "ports"
simultaneously.
The MAJOR ADVANTAGES offered by this technique are:
- Minimal injury to the paraspinal muscles;
- Minimal post-operative pain (compared to standard Microsurgical Bilateral Multi-level Laminectomy);
- Early post-operative mobilization (usually within 4 hours after operation);
- Early post-operative discharge from hospital (either the same day or on the morning following surgery);
- Earlier return to work;
- Reduced overall cost.
Most patients who undergo these operations report
that the pain from the incision in the back is not nearly as
bothersome as the pain which they experienced preoperatively.
In most cases they are essentially immediately free of the
severe leg pain that they had previously endured. The majority of
patients are mobilized out of bed within four (4) hours
post-operative when they are awake and alert and have
recovered from the effects of the anesthetic. This early
mobilization is important in helping to diminish post-operative
muscle spasm. Patients are asked to avoid taking
excessive narcotic analgesic (pain reliever) in the
early postoperative period in order to allow them to be
mobilized. Narcotics make people sleepy. This precludes our
staff from allowing patients to be out of bed. The discomfort
from the incision is rarely seriously painful. Actually once the
patient is out of bed and walking, the pain is usually lessened
even further.
The "Interspinous Process Decompression System" is a
relatively new Minimally Invasive procedure that is
used to relieve the Neurogenic Intermittent Claudication
symptoms of Lumbar Spinal Stenosis.
X STOP® is one such device that has achieved FDA
approval at the time of this writing. There are other
systems (such as the "DIAM" device, the
"Coflex", the "Wallis" and the "Spire") that
are becoming available as well. All of these implants
are either made from titanium or other long-lasting
materials and perform in a similar way. They are
inserted between the "Spinous Processes" (the thin
projections from the back of the Spinal bones to which muscle and
ligaments are attached) of the lower Lumbar Spine.
The therapeutic concept underlying these devices is based upon
the clinical observation that Spinal Stenosis patients tend to
walk with a "bent forward" posture since they have
learned that this is more comfortable. In fact, this
posture actually results in a small (although
frequently sufficient) degree of "opening" or "enlarging" the
Stenotic Spinal Canal. These implants PREVENT THE
PATIENT FROM "EXTENSION" AT THE AFFECTED SEGMENT and "force" a
slight "forward tilt" (anterior-directed flexion) or NEUTRAL
POSITION to the Vertebrae resulting in a similar, more
"permanent", opening of the Spinal Canal. The goal for
this therapy is to relieve some or all of the "Claudication"
symptoms of Lumbar Spinal Stenosis and improve a patient's ability
to function.
These implants are indicated for treatment of patients aged
50 or older suffering from Neurogenic Intermittent
Claudication (pain or cramping in the legs) secondary to
a confirmed diagnosis of Lumbar Spinal Stenosis and for those
patients with moderately impaired physical function who
experience relief in flexion from their symptoms of
leg/buttock/groin pain, with or without back pain, and have
undergone a regimen of at least 6 months of non-operative
treatment. The device may be implanted at one or two Lumbar
levels.
- an allergy to titanium or titanium alloy;
- spinal anatomy or disease that would prevent implantation of the device or cause the device to be unstable in the body, such as:
- significant instability of the lumbar spine
- an ankylosed segment at the affected level(s)
- acute fracture of the Spinous Process or Pars Interarticularis
- significant Scoliosis
- neural compression causing neurogenic bowel or bladder dysfunction;
- diagnosis of severe osteoporosis
- active systemic infection or infection localized to the site of implantation.
Lumbar Disc Herniation & Degenerative Conditions, Part 2
is a comprehensive review of these problems and treatments.
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Spondylolisthesis is a condition where one Vertebral Body
has "slipped" forward (or backwards) upon the adjacent Vertebral
Body resulting in a "misalignment" of the Spine. This clinical
problem may be the result of a progressive degenerative
change in the Facet Joints of the Vertebrae, a traumatic disruption
of these Facet Joints or of a congenital structural defect
involving the portion of the Vertebra that "connects" the Facet
Joint to the Vertebral Body (known as the "Pars
Interarticularis").
In the event of a congenital defect, this problem may
have never previously been apparent and may only be detected in
later years. This term, "Spondylolisthesis", is
almost exclusively reserved for alignment problems of the
Lumbar Spine and results from a failure of "normal" bone structures
to maintain the anatomical alignment of the Spine. This
means that one Vertebra (or occasionally two
Vertebrae) "slips" forward (or backwards) relative to each
other. The degree of slippage is referred to as
either Stage 1 (minor slip of less than a 1/3 of the Vertebral
Body distance); Stage 2 (slippage of a distance 1/3 to 2/3
of a Vertebral Body) or Stage 3 (slippage of greater
than 2/3 of the Vertebral Body distance.) There are
some additional "slippage" problems which include
dislocation of the Vertebral Body to one side (or
"laterally" - a "Lateral Listhesis") which makes surgical
correction even more complicated.
In patients with a congenital form of Spondylolisthesis the
condition becomes apparent in the late teenage years to the
30's. The "congenital" problem responsible for this is a
defect (failure to form) a small bridging Vertebral Bone
element called the "Pars Interarticularis" (see Figure 2).
This means that one or both Facet Joints of one of the Vertebra
have failed to connect to the remainder of its Vertebra resulting
in instability.
Most cases of Spondylolisthesis become apparent during or
after the late 50's. In these cases the Facet Joints
have suffered advanced deterioration and now are incapable
of holding the patient's Vertebrae in normal alignment. This
Degenerative Arthritis (Osteoarthritis) "deterioration" is
due to "micro-trauma" of everyday life occurring over the lifetime
of that particular patient and is usually due to a
combination of factors such as obesity, activity in sports,
weight lifting, heavy work activities, etc. (See "Associated
Pathologies" below.)
"Traumatic" Spondylolisthesis is the least common
form of this entity. Fractures of one or both Facet
Joints of a Lumbar Vertebra may result in this slippage.
These anatomical "misalignments" frequently result in compression
of the Neural Elements (Nerve Roots either within the Spinal
Canal and/or as they exit the Spinal Canal through the
Neural Foramina.) This may cause injury to those
Nerve Roots resulting in neurological problems such as
weakness and/or sensory impairment in the Lower Extremities
which is usually mild in the beginning. In unusually
advanced cases, patients may suffer impairment
of bowel and/or bladder function in addition to
weakness of the muscles of the legs and loss of
sensory function in the Lower Extremities and Perineum.
Pain and/or neurological deficit(s) frequently bring
this condition to the patient's awareness. The degree
of pain varies from one person to the next. Some, with
advanced degrees of slippage (Stage 2) may not have had pain in
previous years despite the fact that there was instability for many
years when their condition was only a Stage 1 variety. Others have
minor degrees of slippage and suffer considerable pain.
Spondylolisthesis may be accelerated by or a potential
associated "cause" of significant additional structural
abnormalities of the Spine.
1. Scoliosis and Rotoscoliosis: Scoliosis (an abnormality
described as a "twisted spine" often also has a "rotary" component
called "Rotoscoliosis") creates an abnormal
"weight bearing" structure resulting in accelerated
degenerative changes in the Facet Joints. As demonstrated
in Figures 6 & 7, these degenerative and destructive
forces cause these Facet Joints to "fail" resulting in
"Spondylolisthesis".
2. Herniated Intervertebral Disc: A Herniated Disc may also
occur at the Spondylolisthesis level presumably as a
result of the "abnormal forces" on the Spondylolisthesis
level which also affects the strength and integrity
of the Posterior Longitudinal Ligament (See Figures 4, 5 & 8
for such examples.)
3. Spinal Stenosis: The progressive degenerative
changes that affect the Facet Joints are often
accompanied by pathological Hypertrophy of the Ligamentum
Flavum. This, in combination with the Hypertrophy of
the Facet Joints and the "slippage" of one Vertebra on the next,
may result in severe Spinal Stenosis. A case illustration
of Stenosis with Spondylolisthesis and a Herniated Disc is
presented in Figures 8 & 9.
There are NO MEDICATIONS that can affect the INSTABILITY
associated with Spondylolisthesis. Anti-inflammatory
medications (usually in the form of Non-steroidal
medications - also called "NSAIDs") may help in the
management of painful flare-ups that are not
related to Nerve Root compression. Once Neurogenic Intermittent
Cauda Equina Claudication and/or Neurological Deficits related to
Nerve Root compression injury occurs, surgical intervention becomes
an important consideration.
In most of these SYMPTOMATIC cases, the indication for
surgical intervention becomes quite clear. Since Spondylolisthesis
is a condition of INSTABILITY OF THE SPINE, surgical treatment
almost always means that some form of "fusion" (stabilization)
operation is required. Although we are often able to
re-establish the precise anatomical integrity of Spinal
Vertebral alignment, for many patients with this condition,
the surgeon can reduce the degree of slippage without
restoring "perfect" alignment and still obtain a very satisfactory
long term clinical result. The degree of the patient's original
slippage together with certain anatomical features
peculiar to that patient may reduce the probability to achieve a
complete anatomical reduction of the slippage; however, rarely does
this compromise the end result provided that stability and adequate
Nerve Root "decompression" has been achieved.
The surgical process involved in Spondylolisthesis
generally requires several distinct steps which are
almost always carried out simultaneously. The
"fusion" portion usually requires placing a device
between the Vertebral Bodies that were previously in
misalignment. The goal will be for bone to grow from one
Vertebral Body to the adjacent one in order to maintain
LONG-TERM STABILITY. Additional STRUCTURAL STABILITY and
ALIGNMENT is established with the incorporation of some
other form of "fixation" device(s) such as pedicle screws and rods,
interspinous fixation device and/or posterior (or postero-lateral)
bone fusion. All of this is meant to demonstrate that there
are several modern stabilization/fusion methods available.
The surgical recommendations are usually discussed on an individual
basis with each patient and depend on the particular clinical
presentation (including neurological status), age, bone density,
degree of slippage, associated structural and medical issues and
weight.
Of particular interest now is the introduction of
Minimally Invasive Spinal Fusion techniques.
These have some significant advantages as a result of
the operations being accomplished with less destruction of
the important Spine Muscles by using relatively small
incisions. Patients undergoing Minimally Invasive Lumbar
Spine Fusion generally experience LESS POST-OPERATIVE
PAIN, which means earlier ambulation, shortened hospital
stay, less risk to hospital associated complications (including
infection), earlier return to work activities and less cost both to
the patient and to society in general.
In our experience, most patients are mobilized earlier,
are usually walking around the hospital ward within 4 hours
of surgery and are discharged from hospital the
morning following surgery.
There is one form of Minimally Invasive "stabilization"
procedure (called "Interspinous Fixation") that is
actually accomplished on an out-patient surgery
basis with discharge from the hospital within several hours
post-operative (see Figures 4, 5 and 12 below).
"Interspinous Fixation" is one form of Minimally Invasive
"fixation" system that is actually accomplished on an
out-patient surgery basis with discharge from
the hospital within several hours post-operative (see Figures 4 & 5
above and 12 below). This procedure can be combined with
Minimally Invasive Decompressive Laminectomy and some form of "Bone
Fusion".
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e-Surgeon @ http://esurgeon.com/
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