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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6048_Библиотеки_им_академика_М_И_Перельмана.pdf
259© Springer Nature Switzerland AG 2020
J. R. O’Brien et al. (eds.), The Resident’s Guide to Spine Surgery,
https://doi.org/10.1007/978-3-030-20847-9_31
Chapter 31
Revision Lumber Decompressions
DavidHanscom and PeterGrunert
Overview
There is a signicant chance that a given lumbar decompression for disc herniations
or stenosis will require future surgery. For soft disc ruptures, the incidence is
between 5–11% [1] and 10–17% for stenosis [2]. The outcomes for revision surgery
are less predictable than primary surgery, and there is much debate about the indica-
tions, pre-op care, and the choice of procedure. This chapter will attempt to high-
light the issues, but the topic is not amenable to offering simple solutions, as there
are so many variables to consider in a given patient.
Soft Disc Ruptures
There is abundant literature regarding the decision-making process for a primary
lumbar decompression for a soft disc rupture. It is clear that a radiculopathy caused
by a soft disc has a high chance of spontaneously resolving with the disc often reab-
sorbing on follow-up MRI scans [3]. A lumbar discectomy, though, will provide
faster pain relief with an earlier return to normal activities, and a low complication
rate. Clinical decision-making is key in that if the patient is OK with the level of
pain and is willing or wanting to wait, then conservative care is the best option.
However, it is important for the physician to provide reasonable pain control, so as
to not push someone toward surgery that could avoid it. If the pain is intolerable or
D. Hanscom (*)
Swedish Medical Center, Seattle, WA, USA
P. Grunert
Astria Health Center, Yakima, WA, USA
260
lasting longer than is tolerable, a lumbar discectomy is a good option with a docu-
mented acceptable success rate around 85% [4].
Lumbar Stenosis
Lumbar stenosis has a different decision-making process than with soft disc ruptures
with the basic difference being that the bony and ligamentous pathology cannot resorb,
such as what usually happens with soft disc ruptures. Other differences include:
• Pathology can exist at multiple levels making the diagnosis of the exact source of
the pain less clear. Soft disc ruptures rarely occur at more than one level.
• With multiple-level involvement, the symptoms are often vague, again making
the exact source of the pain less clear.
• The pathology evolves over time with large variability. Symptom onset is usually
gradual over several years.
• If there is an acute onset of pain in the presence of bony pathology, there is often
a major life stress that has altered the body’s level of adrenaline, cortisol, endor-
phins, and other stress chemicals. Animal studies show that nerve conduction is
increased and therefore the pain threshold is lowered. The preexisting pathology
will be the rst to become symptomatic [5].
Reasons for ongoing or recurrent radiculitis after a primary lumbar decompres-
sion, regardless of the original approach or technique include:
• Inadequate decompression in the form of a retained fragment or inadequate
removal of the bony/ligamentous pathology.
• Surgery was performed at the wrong level.
• Wrong surgery– Intra or extra-foraminal nerve root compression can be missed
by both the radiologist and the surgeon. A central decompression may have been
done when the pathology is more lateral.
• Recurrence of facet capsular hypertrophy resulting in recurrent central or foram-
inal stenosis.
• Recurrent rupture, which occurs between up to 30% of the time within
10years [6].
• New rupture or pathology occurring at a different level.
• Infections– supercial, deep, or a discitis.
• Dural tear/nerve damage, which is rare with a primary discectomy and more
common in stenosis surgery [7].
• Persistent pain from memorized pain circuits similar to phantom limb pain;
40–60% of the time pain can be induced or worsened when operating in the pres-
ence of ongoing chronic pain in any part of the body [8, 9].
All of these possibilities must be taken into account when assessing a patient
with recurrent or ongoing radicular pain post lumbar decompression. It should have
been made clear to the patient that whatever component of back pain existed prior
to surgery rarely resolves and should not have been a factor in deciding on undergo-
D. Hanscom and P. Grunert
261
ing surgery. Ongoing or recurrent LBP is a separate issue and is not a consideration
that will be discussed in this chapter.
A 2011 Medicare database looked at 31,543 patients (>68years-old) who under-
went revision lumbar surgery for stenosis. The greatest predictor of a repeat surgery
was a prior operation performed prior to the index procedure (17.2% vs. 10.6%
without prior surgery). There is a trend to perform a fusion on the initial stenosis
decompression as a “denitive” procedure. The re-operation rate at four-year fol-
low- up was the same for the decompression alone and simple arthrodesis group
(10.7%). The re-operation rate (13.5%) was higher in the complex arthrodesis
group, which was dened as an anterior/posterior procedure or more than two lev-
els. The incidence of re-operation decreased with increasing age and co-morbidity.
This study does not take into account the natural history of progressive disc disease
despite surgery or progressive stenosis of adjacent segments [10].
Clinical Scenarios forRecurrent or Persistent Radiculopathy
There are several clinical scenarios that occur after a lumbar decompression and it
is important to know into what category your patient falls.
• There was never adequate relief of the radicular pain
• The radicular pain decreased for a short time (days to several weeks) but still
persisted
• There was a pain-free interval of several months and the symptoms gradually returned
• There was excellent relief from the index surgery and there is a sudden re-onset
of the same pain.
Any one of these scenarios can occur with or without a neurological decit. This
factor will be discussed later in the chapter. If the recurrent symptoms cause a true
cauda equine syndrome, then that is beyond the scope of this discussion.
To categorize your patient into one of these categories doesn’t take a lot of time,
but there are several necessary components: history, clinical evaluation, and a
review of all prior and current imaging. You must know the whole story in order to
make a thoughtful choice.
History/Clinical Evaluation
It is necessary to understand the starting point; otherwise you cannot accurately
move forward with the correct treatment plan. Here are some of the questions that
need to be asked to place your patient with recurrent or persistent pain into the cor-
rect treatment approach.
It is important to understand the original indications and pathology that neces-
sitated the decompression. Here are a series of concepts to consider:
31 Revision Lumber Decompressions
262
1. Were there adequate indications for the index operation? If there was minimal
pathology or pain, then you are in a difcult spot. You are now trying to solve a
problem created by the surgery when it wasn’t a surgical issue in the rst place.
The following questions can help you sort this out.
– What was the pain pattern prior to the index operation? Was it primarily back
pain or leg pain?
Lumbar decompressions are not effective or indicated for primarily axial
pain. There may be a short placebo decrease in LBP, but it is generally not
sustained. Patients can usually clearly answer this question. If the leg pain is
more severe but of short duration, this is not primarily a radicular problem.
Even with a history of neurogenic claudication, it is often the back, not leg
pain that causes people stop ambulating and sit down for relief.
– How long was it presenting before the surgery? Is this a chronic pain situation
that had not changed much during the few months prior to the surgery?
Chronic formerly was dened as pain that persists after the expected healing
time. Neuroscience research has demonstrated chronic pain is “that which is
memorized and becomes enmeshed with ongoing life experiences. The mem-
ory can’t be erased” [11]. The classic example is that of phantom limb pain,
which can occur in any area of the body. It has been demonstrated that acute
pain shifts from the nociceptive areas of the brain to the emotional ones. The
nociceptive area becomes dormant. Even if the original source of pain was
clearly identiable, brain can and will memorize the pain. It has been docu-
mented to occur within 12months [12].
– What was the pattern of the pain? Did it follow a specic dermatome or was
it diffuse?
Pain from an isolated soft disc rupture should follow a specic matching der-
matome or myotome. If the original pain was diffuse or not a close match,
then the original surgery may not have been a good idea. Surgery is only indi-
cated for a specic identiable structural problem with matching symptoms.
Spinal stenosis can present with diffuse symptoms and doesn’t have to
have an exact match for surgery to be effective. Central stenosis can present
with bilateral or unilateral symptoms and often looks like the lesion should
be at a lower level of spine. If the pain is in a specic dermatome, then the
compression should specically correlate with the pattern of pain whether
proximal to the exiting nerve root level or at the nerve root level.
– Was it consistently positional?
Generally soft disc ruptures are worse with sitting and stenosis is worse with
standing and walking. This is not an absolute pattern but if a stenosis patient
is worse with sitting, that is a warning sign that the scenario is not straightfor-
ward. With severe stenosis and a large disc rupture, the pain can be constant
regardless of the position. This is frequently the case with disc herniations
in the setting of spinal stenosis at the same level, and the disc herniation has
been present for longer than a year. Frequently, the initial presentation of
a disc herniation in the presence of preexisting spinal stenosis causes der-
matomal pain with sitting. However, as the inammation from the herniated
D. Hanscom and P. Grunert
263
disc resolves, the pain may become more like neurogenic claudication and be
more symptomatic with walking or standing.
– How severe was it? Was it bad enough to require surgical intervention?
Probably the most consistent complaint a spine surgeon will hear is that, “If I
just knew how bad my pain could be after surgery, I would never have under-
gone surgery.” If the original pain was relatively mild, then surgery wasn’t
likely to help and often the persistent or recurrent symptoms are much worse.
The current pathology may be similar to the original pathology and more of
the same type of surgery won’t be helpful. You are also now dealing with a
frustrated and often overtly angry patient. Animal studies show that under
stress that nerve conduction increases, and the pain will worsen [5].
– Were there any neurological decits?
This is critical in that many patients suffer neurological decits, usually associ-
ated with a dural tear. If the decit was there pre-op, it may or may not improve
with the index surgery. If the decit occurred after the surgery and is persistent,
then there is a high likelihood that further surgery won’t help improve function.
If the neurological decit is a new presenting complaint, then the whole situa-
tion is different, in that improvement might be more of a possibility, although
the data is scant. Patients will present with “recurrent radiculopathy” when
they really are asking for help in regaining neurological function.
Of note, bowel and bladder symptoms are rarely caused by chronic lumber
spinal canal compression. It is remarkable how tight a lumbar stenosis can be
without GI or GU compromise. It is easier to sort out the situation if the onset
of true cauda equina symptoms are acute and there is a new compression
from any cause. However, without subjective paresthesias or objective sen-
sory changes, bowel and bladders symptoms are unlikely to be from the spine.
The classic symptoms include saddle paresthesias/anesthesia, loss of bladder
control, bilateral leg weakness, and numbness. This is a true emergency.
However, patients more often complain of urgency that gets construed by
the surgeon as a cauda equina syndrome. Even in the presence of severe, even
extreme stenosis, this is not a cauda equine syndrome nor an emergency. It
is more likely to be an irritable bladder syndrome, which is associated with
chronic pain. By treating the chronic pain, these symptoms will subside [13].
– Were the risk factors that have been documented to be associated with poor
outcomes addressed prior to the index operation?
It has been shown in several different ways that surgeons are not address-
ing the risk factors for a poor outcome prior to surgery. A 2014 paper showed
that only about 10% of surgeons are addressing them prior to recommending
surgery [14]. If they weren’t addressed, then it shouldn’t be surprising when
the pain persists after surgery. The risk factors are well-known to all elds of
medicine and include: depression, anxiety, catastrophizing, fear avoidance,
insomnia, obesity, younger age, female, duration of the pain, level of opioid
dependence, disability status, family member on disability, job satisfaction,
smoking, illicit substance abuse, excessive ETOH intake, other chronic pain,
situational stress, and a history of childhood abuse [15–17].
31 Revision Lumber Decompressions
264
Additionally, it has been demonstrated that physicians cannot identify the
“at- risk” patients in the clinical setting. The ability to pick up a high-risk
patient is between 25% and 40%, in spite of the physicians being condent of
their general assessment. It doesn’t matter whether the physician is a rst-year
resident or a senior attending. There is too much to assess in a busy clinic [18].
The high-risk patient with recurrent or persistent symptoms will still
be at risk and unless these issues are systematically addressed and treated.
Otherwise, additional surgery is unlikely to be helpful.
Review ofImaging
It is critical to understand the setting before ordering more tests and then be able to
directly compare the presurgical and postsurgical imaging. If the ongoing pain is essen-
tially all back pain, then just lumbar spine x-rays may be adequate to evaluate for post-
decompression instability. Without radicular symptoms other advanced imaging won’t
add much unless there are some clinical “red ags” regarding more severe pathology.
MRI
An MRI is the imaging test of choice if there is radiculopathy. It can reveal or rule out
many types of pathology. First of all, is there any mass effect at all? Many recurrent
radiculopathies may not have corresponding pathology. If there is no mass effect,
then the workup should look at other potential sources of pain. Some of them include:
• Disc at a higher level– including a thoracic disc
• Shingles– Herpes Zoster can be extremely painful with minimal skin lesions
• Diabetic mononeuritis or amyotrophy
• Other peripheral neuropathies
• ALS usually presents with weakness out of proportion to the severity of the
stenosis
• Tumor – usually metastatic– 50% of mets to the spine present as a radiculopathy
• Persistent phantom-type pain without compression
• Complex regional pain syndrome affecting the back and or leg
If there is a signicant mass effect on the corresponding nerve root with match-
ing symptoms, then the workup is done, and repeat surgery might be considered
depending on the intensity of the pain. It is important to evaluate the origin of the
compression. Residual scar tissue or granulation tissue is normal following decom-
pression surgery and with few exceptions should not be treated surgically. The
pathology could be:
• Retained disc fragment– usually this can be ascertained by comparing the pre-
and post-op scans and the use of gadolinium. Gadolinium is the most useful if
used for scans within the rst year of the index operation. The dye will ow into
scar tissue but not the retained or recurrent fragment.
D. Hanscom and P. Grunert
265
• Recurrent disc rupture– this is also easily identied, as there is usually continu-
ity of the disc fragment in the canal with the disc space. Gadolinium within the
rst year can be helpful in dening the extent of the mass effect.
• Inadequately decompressed canal:
– The superior lateral recess wasn’t adequately removed.
– There is still residual ligamentum avum on the shoulder of the exiting nerve.
– One of the more common scenarios is that the central canal was decompressed
and there is residual intra or extra-foraminal pathology.
• Scar tissue is usually more common with soft disc excisions. There is always scar
tissue that forms after any spine surgery but the brous tissue from a disc exci-
sion seems to create more of it. With primarily bony decompressions, there is
less scar and any residual pathology can usually be more readily identied.
• Synovial cyst– occasionally a cyst can rapidly form after a lumbar decompres-
sion because of instability. Sometimes the instability cannot be picked up on
diagnostic testing, and it is the presence of the cyst that suggests instability. This
is usually associated with translation on exion/extension x-rays as well as uid
in the facet joints on the T2 axial MRI images.
Gadolinium contrast is used within the rst year of the index operations for
potential recurrent disc ruptures. The dye will ow into the scar tissue and the disc
fragment will remain dark. The contrast is not as helpful for recurrent stenosis, as
this usually bony pathology.
Myelo/CT
A common scenario is that the pathology is less clear, and the symptoms are vague,
but somewhat close to matching the abnormalities. It is critical to continue with the
workup. The next logical test is usually the myelogram followed by a CT scan. This
is also indicated in the setting of radiculopathy when the patient cannot have an
MRI for some unrelated reason. If there is a dye-cutoff that matches the symptoms,
then further surgery might be considered. If there is free ow of the contrast, then
surgery should not be a consideration. Surgery is a mechanical solution only for a
structural problem (Fig.31.1).
CT Scan
A CT scan without contrast is most useful in assessing radiculopathy after a stenosis
decompression. Commonly the pars may be weakened from a foraminal decom-
pression and eventually fracture. Although the foraminal stenosis may be identied
on an MRI scan, the pars fracture isn’t easily seen. It is important to identify the pars
fracture in that it requires a fusion (Fig.31.2a, b).
31 Revision Lumber Decompressions
266
Fig. 31.1 A middle-aged
male who had undergone
two successful L4–5
decompressions– one on
each side. He had the
gradual re-onset of
bilateral L5 pain and spent
almost a year working on a
structured nonoperative
care program. His repeat
MRI was difcult to
interpret. This myelo/CT
showed probable scar
tissue impinging the right
L5 nerve root. He
responded well to an L4–5
TLIF/posterolateral fusion
ab
Fig. 31.2 (a) A 29-year-old male with stenosis at L4–5 and L5–S1 from large herniated discs
documented to present for over a year. New onset of paraparesis. Lumbar decompression consid-
ered but workup showed the real problem was the ruptured disc at T10–11. (b) A 50-year-old male
with two failed right L3–4 decompressions. Had chronic LBP as well and right anterior thigh pain.
Under a lot of stress. We spend almost a year on prehab addressing sleep, stress, and anger. Pre-op
his back pain had decreased. This CT scan was 1 year prior to his third operation, which was a right
L3–4 TLIF/ posterolateral fusion
D. Hanscom and P. Grunert
267
AP andFlexion/Extension X-Rays
After decompression for a bony stenosis, the facets might be compromised or the
pars may fracture, creating instability. Flexion/extension x-rays can identify an
instability and guide the surgical treatment toward a fusion. The AP view should
include the hips, as hip arthritis can be confused with an L2 or L3 radiculopathy.
EMG/ NCV
An EMG/NCV can be considered as a conrmatory test if there is a question regard-
ing the level. If there are ongoing acute changes, then this nerve is probably the
cause of the pain. If it is negative or shows only chronic changes, it doesn’t mean
that a compressive lesion isn’t the cause of the pain.
Other etiologies can be considered with an EMG/NCV such as peripheral nerve
entrapment, ALS, and diabetic-associated symptoms.
Blocks
A selective nerve block can help conrm the level of the lesion but is not helpful in
isolation. Neuritis from other noncompressive causes will also calm down with a
corticosteroid injection.
Miscellaneous Diagnostic Considerations
Finally, consider all possibilities. There are many other causes of radicular-type symp-
toms besides a spinal lesion. In addition to the ones mentioned above, they include:
• Sarcomas of the sciatic notch
• Ganglions of the sciatic nerve
• Ovarian/bladder/uterine cancer
• Hip arthritis
• Chondromalacia of the patella
• Iliotibial band tendonitis
• Trochanteric bursitis
• Intra-dural/medullary thoracic spinal cord tumors
• Thoracic AV malformations
• Lateral femoral cutaneous nerve entrapment
• Peroneal nerve entrapment at the bular head
• Piriformis syndrome
• Inammatory sacroiliitis
31 Revision Lumber Decompressions
268
The main reason to mention these diagnoses is that you should only consider a
redo decompression surgery if the spinal pathology is convincing by history, clinical
examination, and imaging. Otherwise continue the workup. Radicular pain is a
symptom; not a diagnosis.
Clinical Scenarios
Never Adequate Pain Relief
If a patient undergoes surgery without any signicant relief of the radicular pain,
then there are several possibilities.
• The index operation was not the correct operation because the pathology wasn’t
convincing to be the cause of the symptoms or the symptoms weren’t severe
enough to warrant surgical intervention.
• The surgery wasn’t technically well-done, or pathology was missed. The techni-
cal problems with a discectomy can arise from a retained fragment. Primary disc
surgery is not as easy as it might seem. I have felt from the beginning that there
is no such thing as a “simple” microdiscectomy. This problem can be minimized
by having the diagnostic scans up on the screen and making sure the surgical
pathology correlates with the imaging. The disc can often be superior to the disc
level and under the dural sac. If there is any feeling of discomfort that the disc
material removed is less than you expected, then keep looking. There is also a
possibility that the disc has resorbed in the time elapsed since the MRI and the
surgery. This should also be considered when operating on an extruded disc frag-
ment, and you nd some granulation tissue without residual fragments.
• With spinal stenosis, there are three ways to inadequately decompress the canal.
Although the central pathology may be severe, the real problem may be in the
foramina. The foramina are best decompressed with an extra-foraminal decom-
pression, which completely opens it up, as well as preserving the pars. A second
problem is that it is easy to leave too much avum on the shoulder of the exiting
nerve root. The most common problem is centrally decompressing the canal but
leaving too much of the overhanging lateral recess.
• The index operation was performed at the wrong level or on the wrong side.
Without going into detail, this occurs more often than you might think. It is one
of the main reasons it is critical to view the imaging upon which the index surgi-
cal decision was made. It is also critical to perform a time out at the time of
intraoperative imaging as well as at the beginning of the operation. Even after
placing a needle and making the incision, it is still easy to end up one level above
or one level below the desired operative disc level.
• There might be a missed diagnosis and the pain might be emanating from another
source. Here are a few examples witnessed by the author:
D. Hanscom and P. Grunert