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James R. Daniell et al.372 Asian Spine J 2018;12(2):372-379
Failed Back Surgery Syndrome: A Review Article
James R. Daniell1,2, Orso L. Osti1,2
1e University of Adelaide, Adelaide, SA, Australia
2Calvary Health Care, North Adelaide Campus, North Adelaide, SA, Australia
Postsurgical spine syndrome is becoming an increasingly common challenge for clinicians who deal with spinal disorders owing to the
expanding indications for spinal surgery and the aging world population. A multidisciplinary approach is most appropriate for patients
who are unlikely to benet from further formal surgical intervention. Anticonvulsant medications are effective in managing neuropath-
ic pain after surgery, whereas opioids are rarely benecial. Neuromodulation via a surgically implanted dorsal column neurostimulator
is gaining popularity owing to its substantial superiority over conventional medical management and/or further surgical intervention.
However, considering that prevention is always better than cure, spinal surgeons need to be well aware of the many poor prognostic
indicators for spinal surgery, particularly psychosocial overlay.
Keywords: Postsurgical spine syndrome; Failed back surgery syndrome; Repeat spinal surgery; Chronic pain management; Neuro-
modulation; Spinal cord stimulation
Copyright Ⓒ 2018 by Korean Society of Spine Surgery
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/)
which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Asian Spine Journal • pISSN 1976-1902 eISSN 1976-7846 • www.asianspinejournal.org
Received Mar 2, 2017; Revised Mar 3, 2017; Accepted May 28, 2017
Corresponding author: Orso L. Osti
Calvary Health Care, 89 Strangways Terrace, North Adelaide, SA 5006, Australia
E-mail: orsolosti@gmai l.com
ASJASJ
Review Article Asian Spine J 2018;12(2):372-379 • hps://doi.org/10.4184/asj.2018.12.2.372
Asian Spine JournalAsian Spine Journal
Introduction
Low back pain (LBP) has been estimated to have a lifetime
prevalence of 60%–80% among the global population,
making it one of the most common health complaints [1].
Approximately 10% of individuals suffering from LBP
have symptoms that persist for longer than 3 months [2].
As a consequence of the large number of patients with
LBP who have sought treatment, a substantial increase in
those undergoing surgery has been observed over the past
two decades.
Failed back surgery syndrome (FBSS) is a term used
to describe a clinical entity that has been acknowledged
since the advent of spinal surgery. It was perhaps best de-
scribed by Follett and Dirks [3] as the “surgical end stage
aer one or several interventions on the lumbar neuroaxis
indicated to relieve lower back pain, radicular pain or the
combination of both, without effect”. A more functional
denition is “when the outcome of lumbar spinal surgery
does not meet the pre-surgical expectations of the patient
and surgeon” [4].
The term FBSS has been criticized for being a clinical
misnomer for both patients and surgeons alike [5]. The
qualier “failed” does little to elucidate the entity, and it is
perhaps most appropriate to abandon this term entirely.
The diagnostic term “postsurgical spine syndrome” per-
haps more accurately describes the aforementioned clini-
cal entity [6].
Between 1998 and 2008, the yearly number of lumbar
fusion surgeries performed in the United States increased
from 77,682 to 210,407, with the total number of spinal
operations exceeding one million in 2002 [7,8]. e direct
yearly cost of spinal fusion surgery in the United States
was over US$ 16 billion in 2004 [9], whereas the overall
Failed Back Surgery Syndrome: A Review Article
Asian Spine JournalAsian Spine Journal
373
failure rate of lumbar spine surgery was estimated to be
10%–46% [10]. Given that these rates have not changed
substantially over the years despite advances in technol-
ogy and surgical technique, the number of patients devel-
oping FBSS can be expected to continually increase [11].
The potential widespread occurrence of this condi-
tion necessitates accurate assessment of this challenging
patient population to best address their symptoms and
deliver the most eective treatment.
The Problem
Repeat spinal surgery is a treatment option with dimin-
ishing returns. Although more than 50% of primary
spinal surgeries are successful, no more than 30%, 15%,
and 5% of the patients experience a successful outcome
aer the second, third, and fourth surgeries, respectively
[12]. e prevalence and incidence of patients with FBSS
are comparable with those of patients with rheumatoid
arthritis. However, patients with FBSS and neuropathic
pain experience higher levels of pain and a poorer quality
of life and physical function compared with those with os-
teoarthritis, rheumatoid arthritis, complex regional pain
syndrome, and bromyalgia [13].
Factors Leading to Failed Back
Surgery Syndrome
1. Patient factors
A number of patient-related factors may be associated
with higher rates of FBSS and should be considered when
discussing treatment options. A patient’s psychosocial
wellbeing has a significant effect on his/her treatment
outcome and pain experience such that Carragee et al.
[14] found poor psychosocial wellbeing to be the stron-
gest predictor of LBP disability in a study comparing
morphological and social risk factors. This is also true
when predicting poor outcomes aer spinal surgery [15].
A large number of patients assessed for spinal surgery
comprise those claiming workers’ compensation or re-
ceiving disability support pension. Both of these groups
have been found to be significantly more likely to have
poorer outcomes aer spinal surgery, with those claiming
workers’ compensation having the poorest outcomes. e
gures become even more alarming aer considering pre-
existing depression [16].
Furthermore, smokers are more likely to experience
poorer outcomes aer spinal surgery [17], and obesity is
an established predictor of higher rates of postoperative
complications [18].
2. Operative factors
A percentage of patients who had undergone spinal sur-
gery may have experienced poor outcomes due to an in-
appropriate surgical choice. As previously mentioned, the
number of prior spinal surgeries is a signicant predictor
of outcome of the following spinal surgery.
A single-level decompressive laminectomy in the pres-
ence of unknown multi-level spinal involvement is unlike-
ly to relieve the patient’s presenting symptoms. Similarly,
decompressive surgery in the presence of predominantly
axial/mechanical pain is unlikely to lead to a satisfactory
outcome. Furthermore, the most commonly reported er-
ror during spinal surgery was wrong-level decompression
[19].
Intraoperative errors during spinal surger y may not
only cause ongoing pain in the same preoperative distri-
bution site but also trigger new pain sources. Each surgery
has the potential to create new segmental instability and
generate further pain with misplaced interbody fusion
gras and implants, which may, for example, potentially
cause neural impingement [19]. In an analysis of 105
lumbar fusion cases with pedicle screw instrumentation,
the incidence rates of screw placement errors and implant
breakage at follow-up were 6.5% and 12.0%, respectively,
with potential for serious neurological complications [20].
Patients undergoing lumbar fusion are at risk of loss of
sagittal balance, particularly when more than one level is
involved. Furthermore, those with reduced sacral tilt aer
surgery have been found to exhibit loss of natural lumbar
lordosis with a resultant increase in stress transfer to the
sacroiliac joints [21].
3. Postoperative factors
1) Early
Immediately following surgery, a number of factors may
lead to operative failure. Procedural complications that
may have deleterious eects on the outcome include he-
matoma formation in the epidural or subdural space, in-
fection, pseudomeningocele, and nerve injury.
James R. Daniell et al.374 Asian Spine J 2018;12(2):372-379
2) Late
Altered biomechanics in the operated spine can potential-
ly shi segmental stress and cause “transition syndrome”.
Changes in load distribution may accelerate degeneration
in segments adjacent to the lumbar fusion, which could
lead to new sources of pain. One long-term radiological
study reported that 36% of the cases developed “transition
syndrome” 5 years after lumbar fusion [22,23] (Fig. 1).
Postlumbar discectomy patients with one-level disc her-
niation have been reported to have an overall recurrence
rate of 5%–25% within 5 years.
Assessment
In the workup of patients with FBSS, the principal clini-
cian involved should be able to utilize the services of a
multidisciplinary team.
1. History
First and foremost, the patient’s psychosocial wellbeing
should be thoroughly assessed. e presence of any psy-
chiatric comorbidity, workers’ compensation claims, or
personal disability claims should be noted. ese factors
should be addressed during treatment and should not be
used to exclude patients from further treatment.
An accurate and detailed pain history is crucial in delin-
eating the likely source of the patient’s pain. e dierence
between predominantly axial pain and neuropathic pain
or the presence of both should be understood. Similari-
ties in the distribution of prior and current pain are also
highly relevant given that new sources of pain may be an
indication of unrelated pathologies [24].
It is always of great importance to eliminate any “red
ags” in the history that may necessitate urgent interven-
tion and investigation, including signs of any bowel or
bladder disturbance, any new or progressive neurological
decit, signs of possible infection, and weight loss or other
symptoms that may indicate an undiagnosed malignancy.
orough documentation of previous treatments should
be included during history taking.
2. Physical examination
Physical examination of patients with FBSS is mainly
performed to eliminate the presence of any ominous di-
agnoses that may have been suggested in the past. In fact,
published studies show that very few clinical signs have a
high predictive value in identifying the source of pain [24].
Although paraspinal tenderness has been shown to be as-
sociated with facet arthropathy, the specicity of this test
is low [25]. A neurological examination should be per-
formed to conrm the absence of progressive neurologi-
cal decit and to establish a baseline prior to any further
intervention.
3. Investigations
e choice of an imaging modality for the FBSS cohort is
dependent on the underlying presumptive diagnosis and
previous treatments.
Plain erect radiographs are of use in the initial assess-
ment of vertebral alignment and the extent of previous
surgical intervention as well as in detecting substantial
and clinically signicant degenerative changes [19]. Plain
lateral dynamic erect radiographs (with extension/exion
views) have been shown to be superior to magnetic reso-
nance imaging (MRI) in detecting spondylolisthesis [26].
However, MRI remains the gold standard in FBSS
owing to its superior contrast enhancement sensitivity
Fig. 1. A typical radiological example of “failed back surgery syn-
drome”: previous L4 to S1 posterolateral fusion with adjacent (L3–L4)
segment degeneration, residual/recurrent neural involvement, broken
screw instrumentation, and loss of lumbar lordosis.
Failed Back Surgery Syndrome: A Review Article
Asian Spine JournalAsian Spine Journal
375
compared with computed tomography (CT) [27]. MRI
with gadolinium has the capacity to distinguish between
epidural brosis, perineural scar tissue, and recurrent disc
herniation as a source of pain [19,25] while being the best
imaging modality for detecting spondylodiscitis [27].
CT is used when MRI is contraindicated owing to the
presence of metalware or non-MRI-compatible cardiac
pacemakers, wherein old-fashioned water-soluble CT–
myelography may be used [24]. CT may also be used in
identifying facet arthropathy and pseudoarthrosis owing
to its ne slice superiority in osseous imaging [28].
Management
1. Conservative
Conservative management should always be attempted
in patients with FBSS who do not require urgent surgery.
Moreover, it should always involve supervised exercise
programs with the dual purpose of improving patients’
core strength and spinal range of motion, which may in-
clude physical therapy and pharmacological management.
Pharmacological therapy may include paracetamol and
nonsteroidal anti-inammatory drugs for axial pain con-
sidering that they have both been shown to be superior to
placebo in reducing LBP [29]. Anticonvulsant drugs have
gained popularity for neuropathic pain, with gabapentin
(Neurontin) and pregabalin (Lyrica) being the most com-
monly used preparations. Gabapentin has been shown to
be superior to naproxen in alleviating back and leg pain
after spinal surgery [30]. Pregabalin plays a role in the
prevention of pain before and aer surgery, with its eect
apparently increasing with time [31].
e use of opioids in chronic LBP has become increas-
ingly controversial and is currently recommended for
only short-term therapy. In fact, opioid treatment should
be limited to a nite course over a few weeks given the ab-
sence of evidence to suggest any long-term pain improve-
ment from its use [32]. Furthermore, mounting evidence
has shown substantial morbidity risks associated with
long-term opioid use, including addiction, dependence,
overdose, and even death [25,32].
As part of the treatment regimen, some evidence sug-
gests that cognitive behavioral therapy leads to a reduc-
tion in pain scores in the immediate postoperative period
and during long-term disability [33]. Physical therapy
may be used as part of a multimodal approach for pain
management given its mild eectiveness in patients with
chronic LBP. However, no consensus exists on the best
type of therapy [34].
2. Repeat surgery
Choosing the most appropriate management modality
should be based on the type and pattern of pain syndrome
experienced by the patient: those suering from predomi-
nantly axial or mechanical pain and those with predomi-
nantly neuropathic lower limb pain.
As mentioned earlier, very few absolute indications ex-
ist for repeat spinal surgery. ese include any disabling
and progressive neurological decit, be it association with
bowel or bladder function impairment, cauda equina syn-
drome, or established spinal instability requiring reopera-
tion [35].
Removal of pedicle screw instrumentation may be con-
sidered during predominantly axial or midline pain aer
lumbar fusion. In fact, a number of such cases showed a
significant reduction in pain scores and opioid require-
ment after implant removal [36]. It is also important to
consider the presence of significant adjacent segment
disease or periprosthetic loosening, which may contribute
to the pain, as well as underlying osteoporosis requiring
appropriate medical management (Fig. 2).
3. Neuromodulation
Spinal cord stimulation (SCS) has been proven to be the
most effective form of semi-invasive treatment in pa-
tients with predominantly neuropathic limb pain. The
PROCESS study, published by Kumar et al. [37] in 2007,
compared conventional medical management (CMM)
alone with SCS+CMM in patients with radicular pain for
6 months following a minimum of one anatomically suc-
cessful procedure for herniated lumbar nucleus pulposus.
Aer 6 months, the percentage of patients experiencing at
least a 50% reduction in pain scores was 9% in the CMM
alone group against 48% in the CMM+SCS group [37].
North et al. [38] in 2005 conducted a randomized study
comparing SCS with reoperation in patients experienc-
ing radicular pain with or without LBP. In the study, suc-
cess was dened as a greater than 50% reduction in pain
and satisfaction with treatment; these endpoints were the
same as those used in previous similar studies. SCS was
more successful than reoperation (nine of 19 patients ver-
James R. Daniell et al.376 Asian Spine J 2018;12(2):372-379
sus three of 26, p<0.01), whereas fewer patients changed
groups from SCS to reoperation [38]. A retrospective
analysis of 16,455 patients with FBSS who underwent ei-
ther reoperation or SCS implantation demonstrated that
those with SCS implantation experienced less than half
the complications compared with those who underwent
reoperation aer 90 days (6.5% versus 14.4%) [39].
The role of SCS in patients with predominantly axial
pain has previously been considered much less promising
than that in patients with radicular pain. A recent multi-
center randomized controlled trial conducted by Kapural
et al. [40] randomized patients with chronic LBP and/
or limb pain to high-frequency SCS (10,000 Hz) (HF10)
or traditional low-frequency SCS (50 Hz). Majority of
these patients (87% and 86.2%, respectively) had under-
gone previous spinal surgery. The primary endpoint of
the study was a minimum pain reduction of 50% without
stimulation-related neurological deficits [40]. The trial
showed that HF10 was superior to traditional SCS in the
treatment of both axial and radicular pain, with HF10
having a better response rate (84.3%) compared with
traditional SCS (43.8%) in patients with axial pain after
3 months. Among those with radicular pain, HF10 and
traditional SCS had response rates of 83.1% and 55.0% af-
ter 3 months of follow-up, respectively [40]. e superior
outcomes of HF10 therapy continued until 24 months in
those with both back and leg pain [41]. e ecacy of the
HF10 therapy has also been confirmed in an Australian
cohort, with high trial success rates and significant pain
reduction among patients who failed to respond to tradi-
tional SCS [42].
A number of other neuromodulation techniques have
also been attempted, including burst, adaptive, dorsal root
Fig. 3. Example of percutaneous placement of electrodes for the man-
agement of persisting axial and neuropathic pain with direct stimula-
tion of the L4 dorsal root ganglion.
Fig. 2. (A, B) Lucency and loosening surrounding both L4 pedicle screw implants 18 months postsurgery with the diagnostic ap-
pearance on bone scan likely to be linked to failure of bony ingrowth into the carbon ber interbody cage used to replace the L4–L5
disc.
AB
Failed Back Surgery Syndrome: A Review Article
Asian Spine JournalAsian Spine Journal
377
ganglion, and peripheral nerve eld stimulation. Based on
one study conducted by Schu et al. [43], only moderate
evidence exists for burst stimulation, which demonstrated
lower pain scores and higher patient satisfaction over 1
week compared with traditional tonic–clonic stimulation
[44]. A prospective study by Liem et al. [45] showed that
dorsal root ganglion stimulation had similar efficacy for
both leg and back pain in patients with FBSS, although
the most signicant reduction was observed for foot pain
(Fig. 3).
Screening patient s for SCS implant ation re quires
comprehensive consultation wherein formal surgery is
conrmed to have no further benet and the patient re-
ceives optimal medical management, has realistic insight
into their condition, and has no evidence of infection. In
general, most trials involving SCS include a trial period
of minimum 10 days with at least a 50% reduction in
pain scores. e surgical implantation of leads is associ-
ated with greater ecacy during the trial period. It is also
worth considering that signicantly higher rates of infec-
tion have been observed when using externalized leads
during the trial.
Conclusions
Our approach to manage FBSS considers the limitations
of surgical intervention on the spine, as well as the vari-
ous patient-related factors that may lead to unsuccessful
outcomes besides the presence of surgically ameliorable
pathology. The decision to perform surgery in patients
with predominantly axial pain should be made with the
understanding that many patients may not respond to the
treatment.
e importance of a competent multidisciplinary team
in FBSS cannot be overstated. Engagement between phy-
sicians, psychologists, physiotherapists, and other allied
health professionals is essential in improving outcomes
for patients with FBSS.
SCS continues to establish itself as the preferred treat-
ment option for patients with FBSS in the absence of a
viable surgical alternative, particularly when radicular/
neuropathic pain, as well as oen when substantial axial
pain, is the main source of disability.
Conict of Interest
No potential conict of interest relevant to this article was
reported.
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