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BMJ. 2008 June 14; 336(7657): 1355–1358. Published online 2008 May 23. doi: 10.1136/bmj.a143. | PMCID: PMC2427077 |
Prolonged conservative care versus early surgery in patients with
sciatica caused by lumbar disc herniation: two year results of a randomised
controlled trial Wilco C Peul, neurosurgeon, epidemiologist,1,2 Wilbert B van den Hout, health economist,3 Ronald Brand, statistician,4 Ralph T W M Thomeer, head of department,1 and Bart W Koes, head of department5, Leiden-The Hague Spine Intervention Prognostic Study
Group 1Department of Neurosurgery, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, Netherlands 2Department of Neurosurgery, Medical Centre Haaglanden, The Hague, Netherlands 3Department of Medical Decision Making, Leiden University Medical Centre 4Department of Medical Statistics, Leiden University Medical Centre 5Research Department of General Practice, Erasmus Medical Centre, 3000 CA Rotterdam, the Netherlands Accepted May 16, 2008. Objectives To evaluate the effects of early lumbar disc surgery
compared with prolonged conservative care for patients with sciatica over two
years of follow-up. Design Randomised controlled trial. Setting Nine Dutch hospitals. Participants 283 patients with 6-12 weeks of sciatica. Interventions Early surgery or an intended six months of continued
conservative treatment, with delayed surgery if needed. Main outcome measures Scores from Roland disability questionnaire
for sciatica, visual analogue scale for leg pain, and Likert self rating scale
of global perceived recovery. Results Of the 141 patients assigned to undergo early surgery, 125
(89%) underwent microdiscectomy. Of the 142 patients assigned to conservative
treatment, 62 (44%) eventually required surgery, seven doing so in the second
year of follow-up. There was no significant overall difference between treatment
arms in disability scores during the first two years (P=0.25). Improvement in
leg pain was faster for patients randomised to early surgery, with a significant
difference between “areas under the curves” over two years (P=0.05). This short
term benefit of early surgery was no longer significant by six months and
continued to narrow between six months and 24 months. Patient satisfaction
decreased slightly between one and two years for both groups. At two years 20%
of all patients reported an unsatisfactory outcome. Conclusions Early surgery achieved more rapid relief of sciatica
than conservative care, but outcomes were similar by one year and these did not
change during the second year. Trial Registry ISRCT No 26872154. In Western countries surgical removal of the herniated nuclear part of an
intervertebral disc is routinely performed to relieve sciatica. The complex of
symptoms encompassing sciatica, more accurately called lumbosacral radicular
syndrome or sciatic neuralgia, is characterised by radiating pain in an area of the
leg typically served by one lumbar or sacral spinal nerve root in combination with
dermatomal motor, sensory, or tendon reflex abnormalities. Some 5-10 of every 1000
inhabitants in Western countries develop sciatica each year, with variable pain
intensities and disease courses. 1 During the
first six weeks the leg pain diminishes in 70% of patients. 2 Most guidelines recommend considering surgery for the
remainder of patients. 3
4
5
6
The number of months needed for spontaneous recovery from sciatica caused by a disc
herniation is not known with certainty. Until a few years ago, only one landmark
randomised trial 7 could be retrieved, and
this showed that that conservative treatment and surgery had similar results after
four years of follow-up among patients with moderate pain intensities. 8 Patients with intense sciatica fear chronic
disability: without adequate short term pain relief, most of them choose surgery.
The uncertainty around the optimal timing of surgery for sciatica probably results
in large variations between countries in the frequency of low back surgery. 9
We previously reported the results of a randomised controlled trial comparing early
surgery with prolonged conservative care for patients with sciatica over one year’s
follow-up. 10 In the current analysis we
provide results for an additional year of follow-up and describe the pain and
disability status of patients at two years. We conducted a multicentre prospective randomised trial among patients with 6-12
weeks of persistent sciatica to determine whether a strategy of early surgery leads
to better outcomes than a strategy of conservative treatment for six months and
delayed surgery for patients with persistent pain. The medical ethics committee at
each of nine participating hospitals approved the protocol. Only centres with
experience to diagnose and treat patients with sciatica conservatively and with at
least 100 surgically treated patients a year were allowed to enrol patients. Written
informed consent was obtained from all patients. Details of the design and study
protocol have been published previously. 11
The current study focuses on the differences between one and two year outcomes. Eligibility and randomisation Eligible patients were aged 18-65 years, had had lumbosacral radicular syndrome
diagnosed by an attending neurologist, and had a radiologically confirmed disc
herniation. Patients were included only if they had a dermatomal pattern of pain
distribution with concomitant neurological disturbances that correlated to the
same nerve root being affected. Before randomisation, participating
neurosurgeons verified the indication for surgery and independently confirmed
the presence of nerve root compression by a herniated disc by means of magnetic
resonance imaging. This nerve root compression had to correlate with the
presented clinical findings. Patients presenting with a cauda-equina syndrome or
severe paresis (Medical Research Council (MRC) score <3) were excluded,
as were those who had had identical complaints in the previous 12 months or a
history of spinal surgery, spinal stenosis, deformity, or severe comorbidity. A computer generated permuted-block scheme was used for randomisation, stratified
according to centre (n=9). One hour before randomisation, patients were again
evaluated by independent research nurses, and any patients who no longer met the
eligibility criteria because of recovery were excluded. The remaining patients
were assigned to a treatment by the opening of successive numbered opaque
envelopes containing the assigned strategy. Patients were notified beforehand
that they were participating in a study comparing two different strategies for
the timing of intervention rather than comparing surgery with non-surgical
treatment. Obviously, they could not be blinded to the assigned treatment
arm. Treatment Early surgery was preferably scheduled within two weeks of
assignment and cancelled only if spontaneous recovery occurred before the date
of surgery. The disc herniation was removed through an unilateral transflaval
approach using magnification. Occasionally, at the discretion of the surgeon, a
bilateral exploration was performed. The participating spine surgeons had ample
experience in lumbar disc surgery and postoperative care. After annular
fenestration and decompression of the nerve root, the potential but
unsubstantiated high risk of a recurrent disc herniation was reduced by removal
of loose degenerated disc material from the disc space using curette and
rongeur, without striving for a subtotal discectomy. During a consensus meeting
before the trial, the surgical method was discussed, and no alternative methods
of surgery were allowed. The duration of hospital stay depended on each
patient’s functional ability to mobilise. After discharge, the rehabilitation
process was supervised by the patient’s physiotherapist at his or her office.
Depending on the nature of their work, patients were advised to resume their
regular jobs after six weeks onwards. Prolonged conservative management was provided by each patient’s
family practitioner. Ample information was supplied about the favourable
prognosis. Treatment comprised the prescription of effective painkillers
according to prevailing guidelines and the advice to resume daily activities if
feasible. A mobilisation scheme, based on time rather than pain, was recommended
without checking the compliance. If patients had considerable fear of movement,
guidance from a physiotherapist was recommended. Fear of movement was assessed
by the family practitioner. The principal investigator instructed the
participating practitioners, and if guidance about pain and disability became
too complicated there was a low threshold to refer patients back to the hospital
office of the research nurses. If sciatica persisted six months after
randomisation, microdiscectomy was considered. Increasing leg pain not
responsive to drugs and progressive neurological deficit were indications to
perform surgery earlier, within six months. Before such surgery was discussed
with patients, they were again evaluated by the research nurses, neurologist,
and neurosurgeon to verify the progressive worsening of sciatica and
radiological confirmation of a disc herniation was repeated. Outcomes Primary outcomes were measured longitudinally over a period of two years by means
of the Roland disability questionnaire for sciatica, 12 a 100 mm visual analogue scale for leg pain, 13 and a 7-point Likert self rating scale
of global perceived recovery. The outcomes were assessed at 2, 4, 8, 12, 26, 38,
52, 78, and 104 weeks. Secondary outcomes—such as a repeated neurological examination, a visual analogue
scale for back pain, functional-economic observational assessments (PROLO) 14 by an independent research nurse, and
quality of life scales 15—were measured
at monitoring visits scheduled at 8, 26, 52, 78, and 104 weeks. Research nurses
observed their own patients at the planned follow-up visits and were aware of
the patients’ treatment assignments. Statistical analysis The aim of this study was to estimate the difference between the two treatments
in disease-specific disability of daily functioning measured with the Roland
disability questionnaire. Assuming a minimal recovery of 11 points and mean
standard deviation of 10 points over the first year, 16 140 patients would be required per treatment arm to
provide a statistical power of 0.90 with a two tailed significance level of 0.05
to detect a four point difference in the disability score. Recovery corresponded to “satisfactory outcome” and was defined as complete or
almost complete disappearance of complaints measured by a 7-point Likert scale.
The other scores corresponded to “unsatisfactory outcome.” The ratio of the
respective speeds of recovery was estimated using a Cox proportional hazard
model, with results presented as hazard ratios with 95% confidence intervals.
Differences between groups in the Likert score at two years were evaluated with
Fisher’s exact test. Data collection and quality checks were performed with the ProMISe web-based
secure data management system of the Department of Medical Statistics and
Bioinformatics of Leiden University Medical Centre. For all statistical
analyses, SPSS version 14.0 was used. Differences between groups at baseline and
after two years of follow-up were assessed by comparing means, medians, or
percentages, depending on the type of variable. Baseline values of variables
were used as covariates in the main analyses whenever appropriate to adjust for
possible differences between the randomised groups and to increase the power of
the analyses. Outcomes of function and pain were analysed using a repeated measurements
analysis of variance with a first order autoregressive covariance matrix.
Estimated consecutive scores were expressed as means and 95% confidence
intervals. Pointwise estimates were obtained using models with time as a
categorical covariate to allow assessment of systematic patterns. Differences
between randomisation groups were assessed by estimating either the main effect
of the treatment or the interaction between treatment and time. As a second
approach to quantification of the differences between the two groups over total
follow-up time, “area under the curve” quantities were calculated between
randomisation and week 104 and subsequently compared using Student’s
t tests. All analyses were performed according to intention to
treat. Between November 2002 and February 2005, 599 patients had a surgical indication for
treatment of sciatica according to their family practitioner (fig 1). After initial consultation with the neurologist,
395 patients met all inclusion criteria and were examined by magnetic resonance
imaging. At the second visit the 283 patients who continued to have sciatica and in
whom a disc herniation had been visualised were allocated to one of two treatment
strategies. No significant differences in baseline characteristics between patients
were noted for the two study groups (table 1 ).
The patients were equally distributed between the nine participating hospitals. | Table 1 Baseline and follow-up characteristics of patients with sciatica. Values are
numbers (percentages) of patients unless stated otherwise |
Since 23 (8%) of the patients were lost to follow-up for various reasons, the study
lost some power. Analyses without or including last scores carried forward provided
similar results in Mantel-Haenszel analyses. Furthermore, baseline characteristics
among dropouts were similar to those of the patients providing the two year
follow-up data. Nevertheless, it remains possible that selective loss to follow-up
occurred. Of the 141 patients assigned to receive early surgical treatment, 16 (11%) recovered
before surgery was actually performed. They did not receive conservative care.
Median time to early surgery for the remaining 125 patients was 1.9 weeks after
randomisation (table 1 ). Of the 142 patients
assigned to conservative treatment, 55 underwent surgery during the first year after
a median of 14.6 weeks (table 1 ) because of
intractable pain (expressed by a mean leg pain score of 54 and a Roland disability
score of 15.0 measured shortly before proceeding to surgery). All patients in the
conservative treatment group, including those treated surgically, received prolonged
conservative care by their family practitioner or neurologist. During the second
year after randomisation, another seven patients received delayed surgical care
because of persistent or intermittent pain, resulting in 62 surgically treated
patients (44%) in the conservative treatment arm. In both treatment groups 6% of surgically treated patients had recurrent sciatica
that led to a second surgical intervention during the two years of follow-up,
representing 3% of the total conservative treatment cohort and 5% of the early
surgery cohort. Complications occurred in 1.6% of all surgical patients, involving
two dural tears and one wound haematoma. None of the complications required an
intervention. None of the patients developed neurological deficit as a result of
surgery or prolonged conservative care. Repeated measurement analysis of the primary continuous outcomes resulted in
different courses over time for disability and pain (table 2 , fig 2). During the first 12 weeks
after randomisation, mean disability and pain scores improved significantly faster
in the early surgery group, but they then converged over the next 3-6 months. The
areas under the curves in fig 2 were significantly
different between the two groups over the two years’ follow-up for leg pain scores
(P=0.05) but were not significant for the disability scores (P=0.25) and back pain
(P=0.41). After the 12 week outcome assessment, no significant differences were
found between the treatment groups for any of the primary outcomes at any of the
remaining assessments. | Table 2 Primary and secondary outcomes from early surgery (ES) versus prolonged
conservative treatment (PCT) for patients with sciatica. Values are means
(SE) unless stated otherwise and are based on intention (more ...) |
During the first year, early surgery achieved a faster rate of perceived recovery
with a hazard ratio of 1.97 (95% CI 1.72 to 2.22, P<0.001). By the end of the
first year of follow-up, however, 95% of patients in both treatment groups had
experienced satisfactory recovery, and this lack of a difference between groups was
maintained for the following year. Some patients, however, did experience a
recurrence of problems after the first year, which resulted in 81.3% of patients in
the early surgery group and 78.9% in the prolonged conservative care group having
satisfactory results at two years (P=0.66) (table 2 ). Irrespective of assigned treatment, the 56 patients (20%) who had unsatisfactory
results according to the global perceived recovery score at two years had
significantly worse scores for disability, leg pain, and back pain scores than those
with a satisfactory outcome (Mann-Whitney U test, P<0.001) (table 3 ) | Table 3 Primary outcome scores among patients treated for sciatica according to
perceived recovery at two years |
Although early surgery roughly doubled the speed of recovery from sciatica compared
with prolonged conservative care, outcomes at one and two years were similar for
both treatment groups. The major advantage of early surgery for patients is more
rapid relief of leg pain, reassurance about recovery, and earlier return to normal
activities. These relative benefits of surgery, however, were no longer significant
by six months’ follow-up, and, even at eight weeks, the statistically significant
difference between treatment groups in primary outcome scores was not sufficient to
be clinically meaningful. Although a strategy of delayed surgery might result in
some extra weeks of discomfort, up to 56% of our patients did not require surgery
for recovery. Since we found similar one year and two year results for both
treatment strategies, neither treatment is clearly preferable. It might therefore be
time to shift from the current situation of physicians’ recommendations about the
need for surgery (often based on their personal preferences) to patients deciding,
with the help of their physician, which treatment strategy is best for them. Until recently, patients lacked knowledge about the risks, benefits, and alternatives
of early surgery compared with prolonged conservative care, and many patients still
believe that surgery is required to prevent paralysis and permanent disability.
However, early surgery did not decrease the risk of an unsatisfactory outcome at one
or two years’ follow-up. Although the risk was relatively low, 20% of our patients
reported recurrent or chronic pain and disability after two years of follow-up. The
duration of follow-up is, however, still modest, and long term follow-up for 5-10
years is needed to obtain reliable data about what proportion of patients become
chronically disabled and to detect a possible difference between treatments in the
risk of unsatisfactory outcome. Limitations of study Patients randomised to conservative care were guided by research nurses, who
provided information and counselling. It was obviously impossible to blind
patients to this, and practical limitations prevented the randomisation result
to be concealed from the independent research nurses. Obviously, research nurses
are not usually available for patient care, which might hamper the
implementation of a strategy of delayed surgery in routine care. However, the
nurses’ counselling function could be performed by nurse practitioners or
physician assistants in the clinician’s office. In both randomisation arms, 95% of patients had reported satisfactory recovery by
the end of the first year’s follow-up according to survival analysis, but at the
two year assessment only 80% of all patients reported that they had recovered.
Some patients who had reported complete recovery within a year of randomisation
later apparently had recurrent symptoms of leg or back pain and, at two years’
follow-up, experienced no improvement or even deterioration compared with their
pre-randomisation status. To solve this problem of relapse, it may be necessary
to redefine “recovery” as the absence of symptoms for a certain minimum period
of time. Unfortunately there are no simple statistical solutions to this
problem, but the theory of multi-state models, currently gaining popularity as
an extension of survival analysis, may offer an answer. Physicians guiding
patients with sciatica should remember that the long term prognosis may be less
favourable than is suggested by the first impression after successful
treatment. Comparison with other studies Our finding that prolonged conservative care ultimately resulted in outcomes
similar to those achieved with early surgery had already been reported by Weber
in 1983, 7 although in our study patients
with intense sciatica “requiring” surgery were excluded. Since Weber reported
that outcome scores converged only after four years, this study did little to
reassure patients with severe sciatica that postponement of surgery might be
effective in the short term and would not be harmful. After this study, several high quality observational cohort series presented
significantly worse results after prolonged conservative care compared with
surgery. Two studies found a threshold of two months of sciatica, after which
the risk of an unsatisfactory outcome with prolonged conservative care
increased. 17
18 Since these studies were not based
on randomised cohorts, baseline factors of patients receiving different
treatments might not have been completely comparable, and therefore
interpretation of the results should be cautious. From our results, it may be
concluded that advising early surgery to all patients with the aim of minimising
the risk of long term disability is not justified. Nygaard et al 19 and Ng and Sell 20 pointed out in comparable
observational studies that delayed surgery after eight and 12 months of sciatica
respectively produced worse results than earlier surgery. These results do not
per se contradict those presented in our trial, but our data do not support the
studies’ conclusions either. Indeed, it is difficult to keep patients with
persistent sciatica on a conservative treatment plan for longer than 8-12
months. However, details of a strategy of surgery before eight months should be
based on a randomised controlled trial that records symptoms at several
different time windows. However, the general conclusions from the randomised trials by Weinstein et
al, 21 Osterman et al, 22 and Butterman 23 do not point to an unsatisfactory outcome of prolonged
conservative care. From these results in conjunction with our own, we conclude
that early surgery in patients with 6-12 weeks of sciatica does not lead to
markedly improved functioning over the first two years. Besides an early gain in
recovery in Ostermann’s and our study, surgery did not reduce the chances of
unsatisfactory outcomes compared with non-surgical care. This conclusion raises doubts about whether there is an optimal timing for
surgery applicable to all patients with sciatica and, indeed, whether surgery
has any effect at all on the natural course of sciatica. One may decide that a
randomised trial of microdiscectomy versus placebo or sham surgery is needed to
evaluate the effectiveness of surgery accurately; but the risk that patients
with severe sciatica would be far less willing to participate than those with
mild or moderate complaints could lead to considerable selection bias. Conclusions The therapeutic role of surgery for sciatica is restricted to faster recovery and
relief of leg pain. This, however, may still be considered a valuable gain by a
large proportion of patients who are not able or willing to await the natural
course of their condition, with possibly delayed surgery. The optimal timing of
disc surgery has not been defined yet. Future trials should consider alternative
definitions of early versus delayed surgery. In compliance with current
guidelines, the patients in our trial had experienced at least six weeks
sciatica; for defining the optimal time for surgery, it might be more
appropriate to compare delayed surgery with surgery within two or four weeks of
the start of symptoms. What is already known on this topic - For patients who have had sciatica for 6-12 weeks, early surgery
provides faster recovery than prolonged conservative care
- After a year, however, results are similar for early surgery and
conservative care
What this study adds - The absence of outcome differences between groups given early
surgery and conservative care after a year remains up to two
years
- The proportion of patients with unsatisfactory outcomes rises by
two years to 20%, and early surgery failed to reduce this
proportion
- Of those patients randomised to prolonged conservative care, 40%
eventually required delayed surgery for relief of symptoms
- Since the treatment effects of early surgery are gone after six
months, well informed patients, rather than physicians, should
decide whether and when to have surgery
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