The prevalence of symptomatic lumbosacral disk herniation is relatively
small. It is important to differentiate between the reasonably well-defined
entity of sciatica resulting from a herniated intervertebral disk and
the less well understood diagnosis of low-back pain. Sciatica is defined
as pain radiating down the course of one or more of the roots of the sciatic
nerve, extending down the nerve to a point below the knee in one or both
legs. Sciatica is merely a symptom, not a specific disease or disorder.
The history and physical exam are among the most important tools in differentiating
this disease process
Incidence and Epidemiology
A symptomatic herniated disk occurs during the lifetime of approximately
2% of the population. In most cases, sciatica improves spontaneously.
When the prevalence of sciatica and the radiculopathy (10% to 25%) is
taken into consideration, it is clear that surgical treatment should be
entertained for less than 0.5% of the population.
The intervertebral disk ages naturally from nuclear dehydration through
a series of inevitable changes. With progressive degeneration, disk material
may herniate, causing nerve root compression. Herniation generally occurs
between the ages of 30 and 50 years. The exact cause of pain radiating
down the leg is controversial. However, it appears that symptomatic lumbar
radiculopathy is a result of mechanical contact between the disk and one
or more nerve roots or a result of a combination of this contact and yet
undetermined biomechanical and vascular factors. Almost 98% of clinically
important disk herniations occur at the L5-S1 (most common) or L4-5 levels.
Symptoms of nerve root
encroachment are variable. They depend on the patient's age and medical
condition, the degree of root compression, the place on the nerve root
or dorsal root ganglion at which the pressure is occurring, and the types
of resultant inflammation and/or pathologic changes around and within
the nerve root.
The most common neurologic impairments are:
• weakness of ankle and great toe dorsiflexors (L5)
• reduced ankle reflexes (S1)
• sensory deficits in the feet (L5 and S1)
Occasionally, a massive midline disk herniation may compress the entire
cauda equina, resulting in bowel or bladder dysfunction, saddle anesthesia
and bilateral lower extremity signs.
History and Physical
It is important to obtain
a complete history and ascertain whether the patient's chief presenting
complaint is low back pain or sciatica. Information about the patient's
general health, past medical history, recent febrile illnesses or any
recent procedures the patient may have undergone are also important.
Typically, true radiculopathy produces pain radiating below the knee and
is associated with numbness or paresthesia following a dermatomal pattern.
The pain is often aggravated by coughing, sneezing or a Valsalva maneuver.
A careful neurologic exam is essential to identify any subtle motor or
Nerve root tension signs further suggest the diagnosis. Straight leg raising
test is defined as positive if it reproduces the patient's sciatica at
less than 60° of leg elevation. Crossed straight leg raising occurs
when straight leg raising is performed on the patient's well leg and elicits
pain in the leg with sciatica. Crossed straight leg raising is less sensitive,
but more specific for lumbar disk herniations, particularly those with
a central component. High (L3-L4) disk herniations can be tested with
a reverse Lasegue test, which is performed with the patient prone by flexing
each knee in turn. This gives rise to pain in the femoral nerve roots
which should be aggravated by hip extension. Screening of the hips by
testing pain-free range of motion should also be performed.
Four criteria are often
discussed as being necessary in order to diagnose symptomatic lumbosacral
• leg pain that is more prominent than back pain
• a dermatomal pain distribution
• positive nerve tension signs
• imaging studies correlating with neurologic signs
Patients with suspected lumbosacral disk herniation should have motor
and sensory exams that elicit objective signs of specific nerve root involvement.
If the motor and sensory abnormalities do not conform to the expected
nerve root distribution, another diagnosis should be considered. In the
absence of any significant or progressive neurological deficits, diagnostic
studies should be delayed until four to six weeks following the onset
of symptoms. Most patients' pain will resolve spontaneously within this
time frame. If symptoms and physical findings persist after conservative
therapy, diagnostic studies should be obtained. Historically, myelography
has been the radiographic study of choice for the diagnosis of a herniated
disk. In recent years, CT and MRI have become the primary imaging modalities
for this condition. It is known that approximately 35% of symptomatic
individuals have evidence of a disk abnormality by myelogram, CT or MRI,
with 20% of those under 60 years of age having imaging evidence of a disk
herniation. In asymptomatic individuals over 60 years of age, over 50%
will have abnormalities. These tests, however, are not without pitfalls
or problems in interpretation.
Both CT and MRI are excellent techniques to detect and characterize disk
herniations. With desiccation and degeneration of the disk, there will
be loss of the high intensity signal in the disk on the T2-weighted images.
Displacement of nuclear material into the region of the outer annular
fibers will cause a focal contour abnormality of the disk. As long as
the disk material is contained by the outer annulus or the posterior longitudinal
ligament, it is considered a contained herniation. If it penetrates the
outer annular-posterior longitudinal ligament complex, it is call a disk
extrusion. If the disk material separates from its disk of origin, it
is called a sequestered fragment.
The mainstay of treatment
remains nonoperative. The majority of patients will improve with limited
periods of bed rest (three to five days), NSAIDs, patient education and
various exercise regimens. Epidural steroids may be of some benefit. A
review of the course of symptomatic lumbar disk herniation reveals that
surgery plays mainly a palliative role in its management. Results of long-term
comparisons of surgical and nonsurgical treatment groups of patients with
herniated disks show no statistically significant differences in outcome.
Results appear initially better in the surgical group, but this difference
diminishes with time. The major benefit of surgical treatment for a herniated
lumbar disk appears to be more rapid relief from sciatic pain than is
provided by nonsurgical treatment.
Indications for surgical
• impairment of
bowel or bladder function
• gross motor weakness
• evidence of increasing impairment of nerve root conduction
• severe sciatic pain persisting or increasing despite 4 to 6 weeks
• recurrent incapacitating episodes of sciatic pain
The acute massive disk herniation that causes bladder and bowel paralysis
appears to be best managed by emergent surgical excision. In the face
of progressing motor weakness, it is best to intervene early with surgical
excision of the disk herniation. It has been shown that patients with
a major neurologic deficit eventually made as much recovery with nonsurgical
treatment as they did with surgical treatment. However, many surgeons
believe that earlier surgery may accelerate neurologic improvement. Failure
of nonsurgical treatment is the most common reason for surgical intervention.
Optimal nonsurgical treatment occurs over at least four to six weeks,
and not more than three to six months. It results in improvement in the
patient's symptoms and signs. When incapacitating symptoms continue for
more than four to six weeks, are substantiated by appropriate findings
(tension signs with or without neurologic deficit), and are verified by
collaborative imaging studies (myelogram, CT, MRI), then surgery may be
appropriate, depending on the patient's desires and needs.
The principal goals of surgical intervention are to relieve neural compression
and the consequent radiculopathy, while minimizing complications. The
most common currently used approach is a limited laminotomy, with disk
fragment excision. This surgery yields similar results whether it is performed
using standard techniques, loupe magnification or a surgical microscope.
More recently, less invasive percutaneous approaches, in which suction,
laser or arthroscopic techniques are used, have been advocated.
Limited excision of a herniated disk for relief of sciatica should provide
relief of symptoms in more than 90% of properly selected patients. Results
of surgery appear to correlate directly with the degree of disk herniation.
More than 90% achieve complete relief of sciatica when a free sequestered
disk fragment is found at surgery; approximately 80% when an incomplete
herniation is present; and 60% to 70% when there is only a protruding
These results emphasize the importance of appropriate patient selection.
The relief of back pain as the predominant symptom is unpredictable and
usually is not obtained at surgery. When back pain is not a major component
of the patient's symptoms before surgery, it can develop postoperatively.
Factors leading to surgical failure as a result of back pain include worker's
compensation issues, cigarette smoking and age over 40 years.
The most common complication associated with lumbar disk excision are
missed pathology, dural tears, and disk-space infection. Some believe
these to be more common with the use of the microscope, but many think
these problems are related primarily to the surgeon's level of experience
or to underlying medical problems
Similar to a microdecompression,
a lumbar laminectomy (open decompression) is a surgical procedure that
is performed to alleviate pain caused by neural impingement. The laminectomy
surgery is designed to remove a small portion of the bone over the nerve
root and/or disc material from under the nerve root to give the nerve
root more space and a better healing environment.
A laminectomy is effective to decrease pain and improve function for patients
with lumbar spinal stenosis . Spinal stenosis is a condition that primarily
afflicts elderly patients, and is caused by degenerative changes that
result in enlargement of the facet joints. The enlarged joints then place
pressure on the nerves, and this pressure may be effectively relieved
with a lumbar laminectomy.
The lumbar laminectomy
(open decompression) differs from a microdiscectomy in that the incision
is longer and there is more muscle stripping.
• First, the back is approached through a two-inch to five-inch
long incision in the midline of the back and the left and right back muscles
(erector spinae) are dissected off the lamina on both sides and at multiple
levels (see Figure 2).
• visualization of the nerve roots.
• The facet joints, which are directly over the nerve roots, may
then be undercut (trimmed) to give the nerve roots more room.
are in the hospital for one to three days, and the individual patient's
mobilization (return to normal activity) is largely dependent on his/her
pre-operative condition and age. Directly following the procedure, patients
are encouraged to walk. However, it is recommended that patients avoid
excessive bending, lifting or twisting for six weeks in order to avoid
pulling on the suture line before it heals.
The success rate of
a laminectomy surgery is favorable. Following surgery, approximately 70%
to 80% of patients will have significant improvement in their function
(ability to perform normal daily activities) and markedly reduced level
of pain and discomfort.
The laminectomy surgical results are much better for relief of leg pain
caused by spinal stenosis, and not nearly as reliable for relief of lower
back pain. Lumbar spinal stenosis is often created by the facet joints
becoming arthritic, and much of the back pain is from the arthritis. Although
removing the lamina and part of the facet joint can create more room for
the nerve roots it does not eliminate the arthritis. Unfortunately, the
symptoms may recur after several years as the degenerative process that
originally produced the spinal stenosis continues.
In certain instances the success rate of a decompression for spinal stenosis
can be enhanced by also fusing a joint. Fusing the joint prevents the
spinal stenosis from recurring and can help eliminate pain from an unstable
segment. Fusion surgery is especially useful if there is a degenerative
spondylolisthesis associated with the stenosis. Generally speaking, if
there is multi-level stenosis from a congenitally shallow canal a fusion
is not necessary; however, if the stenosis is at one level from an unstable
joint (e.g. degenerative spondylolisthesis), then a decompression surgery
with a fusion is a more reliable procedure.
Laminectomy risks and
The potential risks
and complications with a laminectomy procedure include:
• Nerve root damage (1 in 1,000) or bowel/bladder incontinence (1
in 10,000). Paralysis would be extremely unusual since the spinal cord
stops at about the T12 or L1 level, and surgery is usually done well below
• 1 to 3% of the time a cerebrospinal fluid leak may be encountered
if the dural sac is breached. This does not change the outcome of the
surgery, and generally a patient just needs to lie down for about 24 hours
to allow the leak to seal.
• Infections happen in about 1% of any elective cases, and although
this is a major nuisance and often requires further surgery to clean it
up along with IV antibiotics, it generally can be managed and cured effectively.
• Bleeding is an uncommon complication as there are no major blood
vessels in the area.
• In approximately 5 to 10% of cases, postoperative instability
of the operated level can be encountered. This complication can be minimized
by avoiding the pars interarticularis during surgery, as this is an important
structure for stability at a level. Weakening or cutting this bony structure
can lead to an isthmic spondylolisthesis after surgery. Also, the natural
history of a degenerative facet joint may lead it to continue to degenerate
on its own and result in a degenerative spondylolisthesis. Either of these
conditions can be treated by fusing the affected joint at a later date.
Fusion literally translates “to join” and in spine surgery
this means that 2 vertebrae are joined together to make one. There are
many reasons why one would perform a fusion (see below) but in essence
the surgeons endeavours to trick the body into thinking that the two bones
to be fused are a single bone that has broken and then sets up the right
conditions so that in healing the bones heal as one. Just as if you broke
your arm, 2 bones with sticky ends would become one. In the arm’s
case, a plaster cast is applied to hold things in place until the bones
are healed, typically 6 weeks. In the lower back screws, plates, rods,
cages and an external brace take the place of the plaster cast, and full
fusion occurs after 3 months. The “sticky ends” in the case
of the spine are the roughened surfaces of bone. Typically bone graft,
usually the marrow, is taken from the hip and placed between the roughened
surfaces. When bone healing occurs, new bone comes out of the roughened
surfaces and migrates along the transplanted bone to bridge the area to
be fused. Ironically, at 3 months all the transplanted bone has been replaced
by new bone. Understanding all of the above, it becomes clear that although
there are a lot of screws and hardware involved, the operation essentially
joins bone to bone and it takes a full 3 months to heal.
A lumbar fusion is a routine operation. Screws as shown below are placed
between the vertebrae that are to be fused. The bone graft is placed around
these. These screws are made of titanium and usually stay in for life.
lumbar interbody fusion, also known as ALIF, is an operation primarily
performed for the treatment of low back pain. Often, a lumbar discogram
is performed. If the MRI picture showing degeneration of a disk space
matches the level of pain produced during the discogram, then surgery
will have a good chance of helping the pain.
This operation is mainly attempting to help low back pain, although lower
extremity pain is occasionally improved, because the implant into the
disk space spreads the vertebral bodies apart, opening the neural foramen
through which the nerve roots leave the spinal canal.
This procedure is not a good option if a patient is suffering mainly from
lower extremity pain because the nerve roots are not vusialized. A surgery
from a posterior approach is a better option. This may be either a posterior
lumbar interbody fusion (PLIF) or a pedicle screw fixation.
The initial portion (approach) is usually performed by
a vascular surgeon, who exposes the anterior border of the lumbar spine
for the neuro or orthopedic surgeon. The pertinent vascular structures
in this area are the aorta, vena cava, iliac arteries and iliac veins,
as well as the pelvic veins. The ureters are also in the vicinity. Seen
here is a typical retractor system, used by the vascular surgeon to expose
the anterior aspect of the spine. In the close us view, visible are the
iliac arteries, and the anterior body of L5.
the front of the spine is exposed, the surgeon finds the midline, by using
"C arm" (fluoroscopy), which essentially provides an x ray in
real time. The disk interspace is prepared, and then the implant is placed
within the disk space. The implant may be a titanium cage (packed with
cancellous bone from the iliac crest (hip)), threaded on the outside to
prevent backout. It might also be a threaded cadaver bone dowel, taken
from the bone bank. On the right, two cages are seen from the front, implanted
in a translucent spine model.
Often this operation is a stand alone procedure, and the patient is kept
in a lumbar brace for three months postoperatively. On the other hand,
it is occasionally necessary, either early or later on, to supplement
the ALIF with a posterior lumbar fusion using pedicle screws.
The Alif is often supplemented with a pyramidal plate.
When is a disc prosthesis suitable? A disc prosthesis is suitable for
patients who are not older than 65, when one lumbar disc is severely degenerated.
A prosthesis is also suitable for patients with on-going back problems
following an open disc operation. A discography is usually done in advance
to determine which disc is causing the pain.
• What does the disc prosthesis procedure involve? The degenerated
disc is replaced, and at the same time the normal distance between the
two vertebrae is restored. A mobile polyethylene disc is supported on
both sides by stainless steel plates. During the procedure, which is performed
from the front, the prosthesis is firmly inserted resulting in immediate
stability. The prosthesis allows normal motion between the vertebrae.
Thus, the adjacent discs are not over-stressed as they are after a fusion
• What post-op care and rehabilitation
is required? Two hours after the procedure, the patient can walk to his
room. In the majority of cases, there is only minor post-operative pain.
Most patients can be discharged three to five days after the operation.
The patient is then allowed to sit, walk, drive a car or ride a bike.
Six weeks after the procedure there are no more restrictions on physical
• Is this an experimental procedure?
This was an experimental procedure, but the Link-Charite disc prosthesis
(see picture) has been around for 15 years now. However, only a few spine
surgeons have learned the precise technique of this operation. These surgeons
experience very few serious complications. In fact, the complication rate
in the hands of these very experienced surgeons is less than for a regular
fusion operation. In follow-up studies over the last ten years, no signs
of wear have been determined and the incidence of loosening is very rare.
• Can complications occur? Very rarely, complications such as vascular
problems may occur: However, there is always a vasco-surgeon on standby
to control eventual bleeding. The infection rate is very low. Regarding
thrombosis, after their post-op check the patient receives anti-coagulative
protection for two weeks, and before discharge an ultrasound check is
performed to rule out a possible thrombosis.
* Age between 18 and 60 years
* Diagnosis of Degenerative Disc Disease at the L4/L5 or L5/S1 level
* At least six months of conservative treatment
* Previous back surgery (except discectomy, laminotomy or nucleolysis
at the same level) or other spinal surgery at any level
* Multiple levels of degeneration
* Osteoporosis, osteopenia or other metabolic bone disease
* Spondylolisthesis, scoliosis or spinal tumor
* History of chronic steroid use
* Autoimmune disorder
* Morbid obesity
Examples of disc prosthesis
The routine approach to lumbar discs
is left sided, because the inferior vena cava is an obstacle on the right
side. The surgeon stands on the right side of the patient. It is important
to have both hips of the patient slightly flexed during the approach in
order to have relaxation of the iliac vessels, making it easier for their
dissection and retraction. The operative table will be curved in lordosis
after the disc exposure.
skin incision is centred on the umbilicus ;again a fluoroscopic control
may be helpful to have a good orientation for dissection. The approach
is performed above the linea arcuata and the posterior sheath is an obstacle
at the lateral side of the rectus; it has to be divided in order to reach
the extraperitoneal fascia. A complete cleavage of the peritoneum from
the posterior sheath and from the lateral abdominal wall is performed.
this procedure the posterior sheath can be divided and the extraperitoneal
cavity can be progressively enlarged with medial retraction of the peritoneum.
The psoas muscle is identified as a bulging structure; the dissection
on the anterior aspect of the muscle becomes more superficial; dissection
should not be carried on deeply between the iliacus and the psoas muscle.
The common iliac artery is identified
along the medial side of the psoas. The approach to the disc is lateral
to the vessels and the artery must be gently dissected from the psoas
and medially retracted. The common iliac artery is the first element to
be identified ; the iliac vein is more deeply situated; it is seen after
retraction of the artery and it should also be gently dissected and retracted
toward the midline. A complete exposure of the anterior aspect of the
disc is possible but that requires an extensive dissection and retraction
of the iliac vessels. The dissection may be difficult if adhesions of
the vein to the disc are present, and in some cases it may be preferable
to expose only the antero-lateral part of the disc in order to avoid any
insertion of the retractor in this antero-lateral situation, it is possible
to perform a complete disc resection and vertebral plates decortication
under the vessels still protected by the annulus fibrosus. The sympathetic
chain lies more laterally along the psoas muscle on the antero-lateral
side of the disc. The disc approach is medial and the sympathetic chain
is usually not injured during the procedure. The L4 lumbar vessels may
be divided to facilitate the retraction of the blood vessels. The division
of the ilio-lumbar vein is not necessary.
Example of a treated case