surgery versus conservative treatment for symptomatic...

Spine www.spinejournal.com E1335

LITERATURE REVIEW

SPINE Volume 36, Number 20, pp E1335–E1351©2011, Lippincott Williams & Wilkins

Surgery Versus Conservative Treatment for Symptomatic Lumbar Spinal Stenosis

A Systematic Review of Randomized Controlled Trials

Francisco M. Kovacs , MD, PhD , * � Gerard Urrútia , MD , † ‡ § � and José Domingo Alarcón , MD ¶ �

Study Design. Systematic review. Objective. To compare the effectiveness of surgery versus conservative treatment on pain, disability, and loss of quality of life caused by symptomatic lumbar spinal stenosis (LSS). Summary of Background Data. LSS is the most common reason for spine surgery in persons older than 65 years in the United States. Methods. Randomized controlled trials (RCTs) comparing any form of conservative and surgical treatment were searched in CENTRAL, MEDLINE, EMBASE, and TripDatabase databases until July 2009, with no language restrictions. Additional data were requested from the authors of the original studies. The methodological quality of each study was assessed independently by two reviewers, following the criteria recommended by the Cochrane Back Review Group. Only data from randomized cohorts were extracted. Results. A total of 739 citations were reviewed. Eleven publications corresponding to fi ve RCTs were included. All fi ve scored as high quality despite concerns deriving from heterogeneity of treatment, lack of blinding, and potential differences in the size of the placebo effect across groups. They included a total of 918 patients in whom

Lumbar spinal stenosis is defi ned as the reduction of the surface area of the lumbar spinal canal. It is usu-ally caused by spinal degenerative conditions 1 – 5 and is

commonly found to be asymptomatic. 1 – 9 However, symptoms may appear as a result of neurovascular mechanisms (such as reduced arterial fl ow in cauda equina, venous congestion, and increased epidural pressure), 10 – 13 nerve root excitation by local infl ammation, or direct compression in the central canal or the lateral recess. 14

These mechanisms can concur. As a result, symptoms attributed to lumbar spinal stenosis are diverse and include radicular pain down to the leg, numbness, and/or weakness. Because lumbar fl exion increases the available space in the lumbar spinal canal, 1 , 15 the most typical clinical feature is neu-rogenic claudication (pain in the buttocks or legs when walk-ing, which disappears with sitting or lumbar fl exion). How-ever, radicular symptoms, which do not improve in fl exion, can also be attributed to spinal stenosis at the correspond-ing level, and no clinical feature or diagnostic test is a valid diagnostic “gold standard” for concluding that spinal stenosis is the cause of pain in a given patient. 16 Nevertheless, spinal

Form the * Departamento Científi co, Fundación Kovacs, Palma de Mallorca, Spain ; † Iberoamerican Cochrane Center-Servei d’Epidemiologia Clínica i Salut Pública, Institut d’Investigació Biomèdica Sant Pau, Barcelona, Spain ; ‡ CIBER Epidemiología y Salud Pública, Barcelona, Spain ; § Public Health and Research Methodology Programme, Universitat Autonoma de Barcelona, Barcelona, Spain ; ¶ Iberoamerican Cochrane Network, Universidad Surcolombiana, Neiva, Colombia ; and � Red Española de Investigadores en Dolencias de la Espalda, Paseo Mallorca 36, 07012 Palma de Mallorca, Spain .

Acknowledgement date: June 1, 2010. First Revision date: August 16, 2010. Second Revision date: October 12, 2010. Third Revision date: November 17, 2010. Acceptance date: November 18, 2010.

The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.

Foundation and Governmental funds were received in support of this work. No benefi ts in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Gerard Urrutia and José Domingo Alarcón retrieved and independently assessed the references identifi ed through the electronic search. They also independently assessed the methodologic quality of each article and performed data extraction. Francisco M. Kovacs participated with these two authors in solving by consensus any disagreements in quality assessment and data extraction that arose, and also wrote this manuscript. He reports that he had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Address correspondence and reprint requests to Francisco M. Kovacs, MD, PhD, Departamento Científi co, Fundación Kovacs, Paseo Mallorca 36, 3º, 1a, 07012 Palma de Mallorca, Spain; E-mail: [email protected]

conservative treatments had failed for 3 to 6 months, and included orthosis, rehabilitation, physical therapy, exercise, heat and cold, transcutaneous electrical nerve stimulation, ultrasounds, analgesics, nonsteroidal anti-infl ammatory drugs, and epidural steroids. Surgical treatments included the implantation of a specifi c type of interspinous device and decompressive surgery (with and without fusion, instrumented or not). In all the studies, surgery showed better results for pain, disability, and quality of life, although not for walking ability. Results of surgery were similar among patients with and without spondylolisthesis, and slightly better among those with neurogenic claudication than among those without it. The advantage of surgery was noticeable at 3 to 6 months and remained for up to 2 to 4 years, although at the end of that period differences tended to be smaller. Conclusion. In patients with symptomatic LSS, the implantation of a specifi c type of device or decompressive surgery, with or without fusion, is more effective than continued conservative treatment when the latter has failed for 3 to 6 months. Key words: lumbar spinal stenosis , systematic review , randomized controlled trial , surgery , conservative treatment . Spine 2011 ; 36 : E1335 – E1351

DOI: 10.1097/BRS.0b013e31820c97b1

Copyright © 2011 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

BRS204382.indd E1335BRS204382.indd E1335 25/08/11 11:51 PM25/08/11 11:51 PM

E1336 www.spinejournal.com September 2011

LITERATURE REVIEW Surgery Versus Conservative Treatment • Kovacs et al

stenosis is the most common reason for lumbar spine surgery in persons older than 65 years in the United States. 17 , 18

When conservative treatments fail for 3 to 6 months, decompressive surgery is usually considered. The most recent Cochrane review concluded that there was only heteroge-neous and limited evidence on its effectiveness, but it was issued in 2005. 19

Therefore, the objectives of this study were to: (1) system-atically review the evidence on the effectiveness and safety of any form of surgery versus conservative treatment for symptomatic lumbar spinal stenosis, and (2) explore whether available data made it possible to refi ne indication criteria for either type of treatment, on the basis of the existence of spon-dylolisthesis or neurogenic claudication.

MATERIALS AND METHODS

Search and Study Selection An electronic search was performed in CENTRAL (Cochrane library 2009, issue 2), MEDLINE (January 1966–July 2009), EMBASE (January 1980–July 2009), and on the Inter-net through TripDatabase (only for reviews and technical reports). The terms “spinal stenosis,” “lumbar stenosis,” “claudication,” “spinal stenos,” “surgery or surgical,” and “low back pain, lumbago, back pain or backache” were com-bined with the highly sensitive search strategy to identify ran-domized controlled trials (RCTs) developed by the Cochrane Collaboration. 20

Studies were included in this review if they were RCTs pro-viding data on the comparison of the effectiveness or safety of any surgical procedure with any form of conservative treat-ment in patients with neurogenic claudication or sciatica, and lumbar spinal stenosis that had been confi rmed by imaging. No language restriction was applied.

References identifi ed were retrieved and assessed indepen-dently by two authors (G.U. and J.D.A.) to check for inclu-sion criteria. Disagreements were solved by consensus with the third author (F.M.K.).

For studies that included randomized and nonrandomized cohorts, this review considered data only from the random-ized cohort to compare the effectiveness of surgical and con-servative treatments, although adverse events from all patients were gathered. Separate data were also requested from the authors with regard to patients with and without spondylolis-thesis, and neurogenic claudication.

Quality Assessment and Data Analysis Methodological quality of each study was independently assessed by two of the three reviewers (G.U., J.D.A., and F.M.K.), following the criteria recommended by the Cochrane Back Review Group. 21 , 22 Criteria on blindness of patients and therapists were disregarded because they were not appli-cable when comparing surgery with conservative treatment ( Table 1 ). Therefore, the maximum possible score was 9 points and a study was considered as being of “high quality” if it scored 5 points or more.

Data extraction was independently undertaken (G.U. and J.D.A.). Disagreements in quality assessment and data extrac-tion were solved by consensus (G.U., J.D.A., and F.M.K.). Despite what was planned at the design phase, neither a quan-titative synthesis of data nor a sensitivity analysis was possible because of the variability of outcome measures and the het-erogeneity of the methods used across the studies ( Table 2 ). Therefore, a qualitative analysis of data was performed on the basis of the methodological quality of included trials and the consistency of their fi ndings.

RESULTS The electronic search identifi ed 739 references. A total of30 publications, corresponding to 17 studies were identi-fi ed as eligible. Ten publications (nine studies) were excluded because they did not focus on spinal stenosis, 28 – 37 eight publi-cations (two studies) because they were not randomized, 38 – 45 and one publication because it mixed patients who had and had not been randomized, and the authors were not able to provide their data separately. 46

The remaining 11 publications (fi ve studies) were included in this review. 23 – 27 , 47 – 52 For the purpose of this review, individ-ual studies are identifi ed by using the fi rst publications report-ing primary clinical endpoints. 23 – 26 , 50 Three of these studies included data from both observational and randomized cohorts, 23 , 25 , 26 but they were included because the authors provided separate data for those patients in the randomized cohorts. 25 , 26

All studies scored as being of high quality, although the sample size of one of them was very small. 23 Most outcomes were self-reported by the patients and blinding of care provid-ers and patients was not feasible. Hence, outcome assessment was not blinded ( Table 1 ).

The mean age of patients included in the studies ranged between 62 and 70 years. Imaging had documented spinal ste-nosis in all the participants. One study included only patients with spondylolisthesis, 25 one included only patients without spondylolisthesis, 26 one included only patients with spondy-lolisthesis of grade I and lesser, 50 and the other two included patients both with and without spondylolisthesis. 23 , 24 When contacted, the authors from the two latter studies were unable to provide separate data for patients with and without this radiological fi nding ( Table 2 ).

One study included only patients with neurogenic claudica-tion, 50 whereas the other four included patients with pain radi-ating down to the leg, both with and without neurogenic clau-dication. 23 – 26 The authors from two of these studies were able to provide separate data for patients with and without neu-rogenic claudication. 25 , 26 Most patients included in the other two studies reported neurogenic claudication, 23 , 24 although separate data on their evolution were not available ( Table 2 ).

Four studies assessed the effectiveness of decompressive surgery (laminectomy, medial facetectomy, discectomy, and/or removal of osteophytes and hypertrophic ligament fl ava) with or without instrumented or noninstrumented fusion. 23 – 26 The fi fth study assessed the effectiveness of a specifi c type of interspinous implant. 50 The latter was the only study funded




LITERATURE REVIEW Surgery Versus Conservative Treatment • Kovacs et al TA

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and

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th

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surg

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sa

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3 pa

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the

surg

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in th

e no

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case

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who

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to fo

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ach

grou

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f the

pa

tient

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vaila

ble

at

the

last

vis

it (2

yr)

for s

imila

r re

ason

s. M

oreo

ver,

the

high

ra

te o

f cro

ssov

ers

(42%

ove

r-al

l) m

ight

cre

ate

a bi

as to

war

d th

e nu

ll hy

poth

esis

.

In e

ach

grou

p, 2

2% a

nd

25%

of t

he p

atie

nts

wer

e no

t ava

ilabl

e at

the

last

vi

sit (

2 yr

) for

sim

ilar

reas

ons.

Mor

eove

r, th

e hi

gh ra

te o

f cro

ssov

ers

(38%

ove

rall)

mig

ht c

reat

e a

bias

tow

ard

the

null

hypo

thes

is.

Out

of 1

00, 9

pat

ient

s as

sign

ed

to c

ontro

l gro

up w

ithdr

ew

from

the

stud

y be

fore

rece

ivin

g th

eir i

nitia

l epi

dura

l inj

ectio

n as

they

ent

ered

the

stud

y ho

ping

to b

e ra

ndom

ized

to

surg

ery.

Mor

eove

r, at

2-y

r fo

llow

-up

of th

e ca

se, 7

pa

tient

s in

the

surg

ery

grou

p an

d 10

add

ition

al p

atie

nts

in

the

cont

rol g

roup

wer

e no

t av

aila

ble

for a

naly

sis.

Thi

s co

uld

even

tual

ly b

ias

resu

lts

agai

nst s

urge

ry.

(Con

tinue

d)





TAB

LE 1

. (C

ontin

ued)

A

mun

dsen

200

5*

(Ran

dom

ized

Coh

ort)

Mal

vim

aara

et a

l 24

Wei

nste

in e

t al 25

†(R

ando

miz

ed C

ohor

t)W

eins

tein

et a

l 26 ‡

(Ran

dom

ized

Coh

ort)

Zuc

herm

an e

t al 27

§

10W

as th

e tim

ing

of th

e ou

tcom

e as

sess

men

t in

bot

h gr

oups

com

-pa

rabl

e?

Yes

Yes

Yes

Yes

Yes

Det

ails

not

pro

vide

d bu

t re

leva

nt d

iffer

ence

s ar

e un

likel

y to

be.

11W

as a

n an

alys

is b

y in

tent

ion

to tr

eat

perfo

rmed

?

Yes

Yes

Yes

Yes

No

Ther

e w

ere

10 p

atie

nts

who

cro

ssed

ove

r fro

m

cont

rol g

roup

to s

urge

ry

grou

p, fo

rmin

g a

new

gr

oup

desi

gnat

ed a

s gr

oup

RC

+ . T

hese

wer

e re

cord

ed a

s tre

atm

ent

failu

res

in th

eir o

rigin

al

grou

p on

the

basi

s of

IT

T an

alys

is d

urin

g th

e fi r

st 4

yr.

All

patie

nts

wer

e an

alyz

ed

in th

eir o

rigin

al g

roup

re

gard

less

of t

he a

ctua

l tre

atm

ent r

ecei

ved.

Dro

p-ou

ts d

urin

g ca

se fo

llow

-up

wer

e as

sum

ed to

be

negl

igib

le.

The

prim

ary

anal

ysis

was

pe

rform

ed a

ccor

ding

to th

e “i

nten

tion

to tr

eat”

prin

cipl

e.

In a

dditi

on, a

n “a

s tre

ated

” an

alys

is (a

djus

ted

for p

oten

tial

conf

ound

ing

fact

ors)

was

als

o pe

rform

ed to

stu

dy th

e po

ten-

tial e

ffect

s of

cro

ssov

ers.

Sam

e as

in W

eins

tein

et a

l 25 .

Out

com

es fr

om p

atie

nts

who

w

ithdr

ew fr

om th

e st

udy

(7 in

th

e su

rger

y gr

oup

and

19 in

th

e co

ntro

l gro

up) w

ere

not

incl

uded

in th

e re

sults

.

5/9

8/9

8/9

8/9

6/9

Stud

ies

with

mul

tiple

rel

ated

pub

licat

ions

:

* Am

unds

en e

t al 47

and

Am

unds

en e

t al 23

.

† Birk

mey

er e

t al 48

and

Wei

nste

in e

t al 25

.

‡ Birk

mey

er e

t al 48

, Wei

nste

in e

t al 26

, and

Wei

nste

in e

t al 49

.

§ Zuc

herm

an e

t al 50

, Zuc

herm

an e

t al 27

, Hsu

et a

l 51 , a

nd A

nder

son

et a

l 52 .

ITT

indi

cate

s “i

nten

tion

to tr

eat’’

; R

C, r

ando

miz

ed c

ohor

t.





BLE

2. C

hara

cter

istic

s of

the

Incl

uded

Stu

dies

Stud

yPa

tient

sSu

rgic

al P

roce

dure

Con

serv

ativ

e Tr

eatm

ent

Follo

w-u

pLo

sses

to

Follo

w-u

p

Am

unds

en e

t al 23

(Ran

dom

ized

co

hort)

A to

tal o

f 31

patie

nts

with

sci

atic

a to

geth

er w

ith ra

diol

ogic

sig

ns o

f st

enos

is a

nd c

ompr

essi

on o

f the

cl

inic

ally

affl

icte

d ne

rve

root

s.

Dis

c he

rnia

tions

and

spo

ndyl

olis

is

excl

uded

.

Mos

t pat

ient

s w

ith n

euro

geni

c cl

audi

-ca

tion

(num

ber u

nkno

wn)

.*

No.

of p

atie

nts

with

spo

ndyl

olis

thes

is

unkn

own.

*

n =

13

patie

nts.

Dec

ompr

essi

on (l

amin

ecto

my,

face

tec-

tom

y, d

isce

ctom

y, re

mov

al o

f ost

eo-

phyt

es, a

nd h

yper

trofi c

liga

men

t fl a

va),

with

out f

usio

n.

+ S

tabi

lizin

g or

thos

is fo

r 3 m

o, “

back

sc

hool

,” re

habi

litat

ion

for 1

mo,

and

su

bseq

uent

sta

biliz

ing

exer

cise

s.

n =

18

patie

nts.

Stab

ilizi

ng o

rthos

is (f

or a

ll ac

tiviti

esdu

ring

the

day)

for 3

mo,

“ba

ck s

choo

l,”

reha

bilit

atio

n fo

r 1 m

o, a

nd s

ubse

quen

t st

abili

zing

exe

rcis

es.

6 m

o, 1

, 4, a

nd

10 y

rSu

rger

y: 1

(4 y

r), 2

(1

0 yr

)

Con

trol:

2 (4

yr),

4

(10

yr)

Mal

miv

aara

et a

l 24

A to

tal o

f 94

patie

nts

(mea

n ag

e: 6

2 yr

) w

ith p

ain

irrad

iatin

g to

legs

or b

ut-

tock

s fo

r ≥ 6

mo,

fatig

ue o

r los

s of

se

nsat

ion

in th

e le

gs a

ggra

vate

d by

w

alki

ng, n

o ne

urol

ogic

dys

func

tion,

an

d sp

inal

ste

nosi

s (s

agitt

al d

iam

eter

of

the

dura

l sac

< 10

mm

).

No.

of p

atie

nts

with

spo

ndyl

olis

-th

esis

or n

euro

geni

c cl

audi

catio

n un

know

n. †

n =

50

assi

gned

(45

wer

e ac

tual

ly o

per-

ated

on)

.

Segm

enta

l dec

ompr

essi

on a

nd u

nder

-cu

tting

face

tect

omy,

with

or w

ithou

t fu

sion

(with

or w

ithou

t tra

nspe

dicu

lar

inst

rum

enta

tion)

.

+ B

roch

ure

on s

pina

l ste

nosi

s an

d th

e pr

inci

ples

of a

ctiv

atio

n an

d ph

ysic

al

train

ing,

edu

catio

n on

pai

n-re

lievi

ng

body

pos

ture

s, e

rgon

omic

s, a

nd in

di-

vidu

aliz

ed e

xerc

ises

.

n =

44

assi

gned

(40

actu

ally

trea

ted

with

-ou

t sur

gery

).

NSA

IDs,

phy

siot

hera

py (u

ltras

ound

and

tra

nscu

tane

ous

nerv

e st

imul

atio

n an

d ex

erci

se) f

or 2

4% o

f the

pat

ient

s.

+ B

roch

ure

on s

pina

l ste

nosi

s an

d th

e pr

inci

ples

of a

ctiv

atio

n an

d ph

ysic

al

train

ing,

edu

catio

n on

pai

n-re

lievi

ng

body

pos

ture

s, e

rgon

omic

s, a

nd in

di-

vidu

aliz

ed e

xerc

ises

.

6 m

o, 1

and

2

yrSu

rger

y: 3

(2 y

r)

Con

trol:

4 (2

yr)

Wei

nste

in e

t al 25

(Ran

dom

ized

co

hort)

A to

tal o

f 304

pat

ient

s (m

ean

age:

66 y

r) w

ith n

euro

geni

c cl

audi

catio

n or

sci

atic

a fo

r ≥ 3

mo,

and

spi

nal

sten

osis

and

deg

ener

ativ

e sp

ondy

lo-

listh

esis

see

n on

imag

ing.

Spon

dylo

lisis

and

isth

mic

spo

ndyl

olis

-th

esis

exc

lude

d.

Spon

dylo

listh

esis

in 1

00%

.

Neu

roge

nic

clau

dica

tion

in 8

6%.

n =

159

ass

igne

d (1

01 w

ere

actu

ally

op

erat

ed o

n).

Post

erio

r dec

ompr

essi

ve la

min

ecto

my

with

or w

ithou

t bila

tera

l sin

gle-

leve

l fus

ion

(with

or w

ithou

t pos

terio

r pe

dicl

e sc

rew

inst

rum

enta

tion)

.

n =

145

ass

igne

d (7

0 w

ere

actu

ally

tre

ated

with

out s

urge

ry).

At l

east

act

ive

phys

ical

ther

apy,

edu

catio

n,

or c

ouns

elin

g in

clud

ing

inst

ruct

ions

for

exer

cisi

ng a

t hom

e, N

SAID

s if

tole

rate

d.

6 w

k, 3

and

6 m

o, 1

, 2,

and

4 yr

‡

Surg

ery:

15

(1 y

r), 2

7 (2

yr),

52

(4 y

r)

Con

trol:

11 (1

yr),

25

(2 y

r), 4

6 (4

yr)

Wei

nste

in e

t al 26

(Ran

dom

ized

co

hort)

A to

tal o

f 289

pat

ient

s (m

ean

age:

65.5

yr)

with

neu

roge

nic

clau

dica

-tio

n or

sci

atic

a fo

r ≥ 3

mo

and

spin

al

sten

osis

see

n on

imag

ing.

Spon

dylo

lysi

s an

d sp

ondy

lolis

thes

is,

excl

uded

.

Spon

dylo

listh

esis

in 0

%.

Neu

roge

nic

clau

dica

tion

in 7

9%.

n =

138

ass

igne

d (9

2 w

ere

actu

ally

op

erat

ed o

n).

Post

erio

r dec

ompr

essi

ve la

min

ecto

my.

n =

151

ass

igne

d (8

6 w

ere

actu

ally

tre

ated

with

out s

urge

ry).

At l

east

act

ive

phys

ical

ther

apy,

edu

catio

n,

or c

ouns

elin

g in

clud

ing

inst

ruct

ions

for

exer

cisi

ng a

t hom

e, N

SAID

s if

tole

rate

d

6 w

k, 3

and

6

mo,

1, 2

, and

4

yr

§

Surg

ery:

18

(1 y

r), 3

0 (2

yr),

54

(4 y

r)

Con

trol:

25 (1

yr),

38

(2 y

r), 6

5(4

yr)

(Con

tinue

d)





BLE

2.

(Con

tinue

d)

Stud

yPa

tient

sSu

rgic

al P

roce

dure

Con

serv

ativ

e Tr

eatm

ent

Follo

w-u

pLo

sses

to

Follo

w-u

p

Zuc

herm

an e

t al 27

(2

005)

A to

tal o

f 200

pat

ient

s, ≥

50 y

r (m

ean

age:

70

yr),

able

to w

alk

≥ 50

feet

, w

ith le

g, b

utto

ck, o

r gro

in p

ain

that

w

as re

lieve

d du

ring fl e

xion

.

Mot

or d

efi c

it, s

pond

ylol

isth

esis

>

Gra

de I,

and

pre

viou

s lu

mba

r sur

-ge

ry e

xclu

ded.

Spon

dylo

listh

esis

gra

de I

in 3

9%. †

Neu

roge

nic

clau

dica

tion

in 1

00%

.

n =

100

Inte

rspi

nous

Pro

cess

Dis

tract

ion

Syst

em

(X S

TOP)

.

n =

100

(91

wer

e ac

tual

ly tr

eate

d w

ithou

t su

rger

y).

Patie

nts

rand

omiz

ed to

the

cont

rol g

roup

re

ceiv

ed a

t lea

st o

ne e

pidu

ral s

tero

id

inje

ctio

n af

ter e

nrol

lmen

t and

wer

e pr

e-sc

ribed

add

ition

al e

pidu

ral s

tero

id in

jec-

tions

, non

ster

oida

l ant

i-infl

am

mat

ory

med

icat

ions

, ana

lges

ics,

and

phy

sica

l th

erap

y as

nec

essa

ry. P

hysi

cal t

hera

py

cons

iste

d of

bac

k sc

hool

and

met

hods

su

ch a

s ic

e pa

cks,

hea

t pac

ks, m

assa

ge,

stab

iliza

tion

exer

cise

s, a

nd p

ool t

hera

py.

6 w

k, 6

mo,

1 an

d 2

yrSu

rger

y: 7

(2 y

r)

Con

trol:

19 (2

yr)

* A to

tal o

f 100

pat

ient

s w

ere

recr

uite

d in

this

stu

dy, 9

1 of

who

m h

ad n

euro

geni

c cl

audi

catio

n. A

mon

g th

ose

100

patie

nts,

onl

y 31

wer

e ra

ndom

ized

. Mea

n ag

e of

thos

e 31

pat

ient

s an

d ho

w m

any

of th

em h

ad

spon

dylo

listh

esis

or

neur

ogen

ic c

laud

icat

ion

is u

nkno

wn.

The

se d

ata

are

not g

iven

in th

e ar

ticle

and

the

auth

ors

coul

d no

t pro

vide

the

sam

e.

† And

erso

n et

al 52

.

‡ Wei

nste

in e

t al 49

.

§ Dat

a su

pplie

d by

the

auth

ors

of th

e or

igin

al s

tudy

.

by the industry, as opposed to public or not-for-profi t sources, in which at least one author had potentially relevant confl ict of interest. 50

Treatments in the conservative arms of those studies included different or nonspecifi ed types of orthosis, rehabilita-tion, physical therapy, exercise, nonsteroidal anti-infl ammatory drugs, analgesics, and education, as well as heat and cold, transcutaneous electrical nerve stimulation, ultrasound, and epidural steroids.

The decision on the kind of surgery or conservative treat-ment applied to each patient was left up to the therapists and no explicit criteria were used.

Follow-up ranged between 2 and 10 years. Variables that were assessed during follow-up included pain, function, clau-dication distance, quality of life, and patients’ overall rating and satisfaction, although instruments used to assess those variables varied across studies ( Table 3 ). Disability, as mea-sured by the Oswestry Disability Index at 2 years, was the only outcome that was assessed in 3 studies or more ( Figure 1 ). 24 – 26 Losses to follow-up ranged between 7.7% (at 1 year) and 44.0% (at 4 years), and were roughly similar between the sur-gical and conservative arms ( Table 2 ).

Small improvements were generally seen in the patients treated conservatively and in whom no catastrophic com-plications such as cauda equina syndrome arose. Changes in claudication distance were similar between conservative and surgical groups. 24 However, results of all the studies consis-tently favored decompressive surgery (with or without fusion) for improvement of pain, function, and quality of life, as well as in terms of patients’ satisfaction. 23 – 26 Crossover rates ranged between 9% and 54%, and affected patients assigned to both the conservative and surgical groups ( Table 3 ). In the two studies with higher crossover rates, 25 , 26 differences between conservative and surgical treatments were statisti-cally signifi cant only in the “as treated” analysis. The only exception was 36-item Medical Outcomes Study Short-Form General Health Survey (SF-36)—“bodily pain,” which even in the “intention to treat” analysis favored surgery at 2 years in one of these studies. 26

The advantage of surgery was already noticeable at 3 to 6 months and remained constant for up to 2 to 4 years, although by the end of that period the differences tended to be smaller ( Table 3 ). In general, the magnitude of the addi-tional improvement triggered by surgery in pain and function was clinically relevant. 53 , 54 Surgery was more effective than conservative treatment for patients with and without spondy-lolisthesis. Surgery was also more effective than conservative treatment for patients with and without neurogenic claudica-tion, although the advantage of surgery was generally greater for the former ( Table 3 ).

The interspinous implant also led to a better evolution than conservative treatment with regard to pain, function, quality of life, and patients’ satisfaction. 27 , 50 – 52 Differences were statisti-cally signifi cant at 6 weeks and remained so till 2 years later. Results favored the implant over conservative treatment to the same extent in patients with and without (Grade I) spondylolis-thesis. This radiological feature was not predictive of outcome. 52





surgery should be balanced against expected improvements for each individual patient.

In patients aged 50 years or older with neurogenic claudi-cation and spondylolisthesis of Grade I who are able to walk 50 feet or more and have no motor defi cit, the implantation of a specifi c type of interspinous distraction device also leads to better results than conservative treatment for up to 2 years. 27 Results beyond this time period are unknown. The evidence supporting these results derives from industry-funded studies whose authors harbored confl icts of interests. 27 The effective-ness or safety of other interspinous implants is unknown and no study has directly compared decompressive surgery with the interspinous implant.

Only among patients who have spondylolisthesis, adding fusion to decompression may improve the results of surgery for lumbar spinal stenosis. 58 – 60 However, fusion increases major complications, 30-day mortality, and resources used. 55 In patients who have fusion, instrumented and noninstru-mented fusion lead to similar results. 27 , 61 , 62 Among patients who undergo instrumented fusion, simpler procedures ( i.e ., anterior or transverse process or posterior fusion, at only 1 or 2 levels) are safer than complex ones ( i.e. , any combination of simple procedures, 360º fusion, or fusion of more than two levels) 19 , 55 , 62 – 64 and lead to similar results. 61

In all the studies included in this review, each care provider decided the form of conservative or surgical treatment applied to a given patient without following any predefi ned indication criteria. This approach was probably the only feasible one, but it led to treatments within the conservative and surgical groups being as heterogeneous as they are in routine practice both across studies and across patients in the same study. This precludes any conclusion on the comparative effectiveness of any particular form of surgery or conservative treatment. However, surgery was more effective than conservative treat-ment across all the studies and results of surgery were roughly consistent among different surgeons in trials conducted in the United States and Scandinavia. This may suggest that their criteria were somehow consistent or that potential differences in their criteria or in the different surgical techniques used do not have a signifi cant infl uence on results.

Data from observational or nonrandomized cohorts were excluded from this review because of concerns regarding the risk of unknown biases. However, despite being classifi ed as “high quality” according to methodological criteria, 21 , 22 con-cerns exist with regard to the studies included in this review. One study recruited only 31 patients, 23 another included only 94, 24 and none conducted a power analysis. As a result, sample sizes may have been insuffi cient to detect differences for some outcomes. Treatments used in both the surgical and conservative groups were heterogeneous and were not selected according to explicit criteria. To be eligible, patients had to have previously undergone conservative treatment unsuc-cessfully, which may have made it diffi cult to recruit large samples, affected the comparability of the unspecifi c effects across groups ( e.g ., Hawthorne or placebo), and increased rates of withdrawal, dropout, and crossover. 23 , 25 , 26 Although results consistently favored surgery, in the two studies with

Adverse events among patients treated conservatively included injection intolerance, symptom fl are, leg paresthe-sia, and increased back pain. Among patients who under-went decompressive surgery, with or without spinal fusion, between 5.4% and 14% suffered from perioperative compli-cations (the most common being, in all studies, dural tears). Postoperative complications arose in between 8.2% and 18% of the patients and included pulmonary edema, peri-dural hematoma, sepsis, and misjudgment of stenotic level. Reported reoperation rates were 1.3% to 2% at 1 year, 6% to 11% at 2 years, and 15% at 4 years. The rate of recurrent stenosis at 4 years was 5%. The mean duration of the opera-tion was 120 to 199 minutes and the mean blood loss was 198 to 589 mL. 25 , 26 The number of deaths were similar in the surgical and conservative groups. The overall postoperative death rate ranged between 0.3% and 0.5%. Approximately 90% of the patients undergoing surgery did not suffer from any adverse event.

Adverse events related to the implantation of the inter-spinous distraction device included asymptomatic spinous process fracture (1%), malpositioned implant (1%), implant dislodgement or migration (1%), increased pain at implant level (1%), wound dehiscence (1%), wound swelling (1%), incisional pain (1%), and hematoma (1%). In addition, one patient suffered from respiratory distress, another from a transient ischemic coronary episode, and a patient with a his-tory of cardiovascular disease died from pulmonary edema 2 days after device implantation. The reported mean blood loss was 46 mL, the mean duration of the procedure was54 minutes, and 96% of the patients stayed in the hospital for less than 24 hours. Among the patients in whom the inter-spinous distraction device was implanted, 7% subsequently underwent a laminectomy. Among those with spondylolisthe-sis, this percentage was 11.9%.

DISCUSSION These results suggest that in patients with radicular pain caused by spinal stenosis, in whom conservative treatment has failed for 3 to 6 months, decompressive surgery (with or without fusion) does not improve walking ability but improves pain, function, and quality of life to a greater extent than continuing conservative treatment. Surgery is superior to conservative treatment irrespective of the patients’ degree of affectation whether they have spondylolisthesis or neuro-genic claudication. However, slightly better results for surgery can be anticipated in patients with neurogenic claudication. Patients should be aware that the benefi ts of surgery decrease with time but still remain signifi cant till 4 (and possibly 10) years later. 23 , 49 Results in the longer term are unknown. How-ever, obtaining a clinically relevant improvement for such a period is worthwhile even if it were to fade thereafter.

Surgery for spinal stenosis can be effective despite advanced age, multilevel involvement, or common comorbidities such as diabetes, obesity, chronic coronary disease, or chronic lung diseases. 26 , 55 – 57 However, these features, especially the latter, and hospitalizations in the previous year are associated with more complications and mortality. 55 Therefore, the risks of





Figure 1. Forest plot showing the results on disability in the three studies that used this instrument, according to the (A) “intention to treat” and (B) “as treated.” In these studies, the disability was measured by the Oswestry Disability Index at 2 years.





BLE

3. S

umm

ary

of R

esul

ts

Stud

y

Patie

nt’s

Glo

bal A

s-se

ssm

ent*

(“G

ood

Res

ult”

) †

Pain

(“W

ith-

out P

ain”

or

“M

ild

Pain

”) ‡

Leg

Pain

§ B

ack

Pain

§ D

isab

ility

(OD

I) ¶

SF-3

6B

odily

Pai

n � SF

-36

Phys

ical

Fun

ctio

n **

Oth

er O

utco

mes

Am

unds

en e

t al 23

(Ran

dom

ized

coh

ort)

1 yr

: RR

2.0

7 (0

.98–

4.38

)

4 yr

: RR

1.9

4 (1

.14–

3.31

)

10 y

r: R

R 3

.18

(0.9

7–10

.41)

1 yr

: NR

4 yr

: RR

3.3

3 (0

.77–

14.3

3)

10 y

r: R

R 1

.59

(0.5

5–4.

55)

Oth

er o

utco

mes

(cla

udic

a-tio

n or

wal

king

dis

tanc

e;

leve

l of d

aily

act

ivity

; an

d ne

urol

ogic

defi

cits

) w

ere

not r

epor

ted

sepa

-ra

tely

for t

he ra

ndom

-iz

ed c

ohor

t.

Mal

miv

aara

et a

l 24

1 yr

: MD

1.6

9 (0

.41–

2.96

)

2 yr

: MD

1.5

1 (0

.25–

2.77

)

1 yr

: MD

2.3

3 (1

.12–

3.55

)

2 yr

: MD

2.1

3 (0

.98–

3.28

)

1 yr

: MD

11.

3 (4

.3–1

8.8)

2 yr

: MD

7.8

(0.8

–14.

9)

≥ 1

0-po

int r

educ

tion

(OD

I):

1 yr

: RR

2.1

6 (1

.31–

3.57

)

2 yr

: RR

1.3

6 (0

.88–

2.10

)

Wal

king

dis

abili

ty (w

alki

ng

dist

ance

< 1.

250

m)*

**

1 yr

: RR

0.9

3 (0

.61–

2.03

)

2 yr

: RR

1.0

8 (0

.70–

2.42

)

Wal

king

dis

abili

ty (w

alki

ng

dist

ance

< 40

0 m

) ***

1 yr

: RR

0.9

1 (0

.51–

4.24

)

2 yr

: RR

1.1

8 (0

.67–

4.72

)

Wei

nste

in e

t al 25

(Ran

dom

ized

coho

rt—al

l)

“Int

entio

n to

trea

t”:

2 yr

: DM

C 2

.2 ( −

2.3

to 6

.8)

4 yr

: DM

C 4

.1 ( −

0.8

to 9

.1)

“As

treat

ed”:

2 yr

: DM

C −

15.9

( − 20

.2

to −

11.7

)

4 yr

: DM

C −

16.2

( − 20

.7

to −

11.6

)

“Int

entio

n to

trea

t”:

2 yr

: DM

C 1

.5 ( −

4.2

to 7

.3)

4 yr

: DM

C −

2 ( −

8.6

to 4

.6)

“As

treat

ed”:

2 yr

: 17.

8 (1

2.5

to 2

3)

4 yr

: 17.

1 (1

0.9

to

23.4

)

“Int

entio

n to

trea

t”:

2 yr

: DM

C 1

.9 ( −

3.7

to 7

.5)

4 yr

: DM

C −

3.1

( − 9.

2 to

3.0

)

“As

treat

ed”:

2 yr

: 16.

7 (1

1.4

to 2

2.1)

4 yr

: DM

C 1

9.2

(13.

4 to

25.

1)

Oth

er o

utco

mes

(pat

ient

’s sa

tisfa

ctio

n; S

teno

sis

Bot

hers

omen

ess

Inde

x,

Leg

Pain

Bot

hers

omen

ess

Scal

e; a

nd L

ow B

ack

Pain

Bot

hers

omen

ess

Scal

e) w

ere

not p

rovi

ded

sepa

rate

ly fo

r the

ran-

dom

ized

coh

ort.

(Ran

dom

ized

co

hort—

with

neu

-ro

geni

c cl

audi

ca-

tion)

� �

“Int

entio

n to

trea

t”:

2 yr

: DM

C −

2 ( −

7.8

to 3

.9)

4 yr

: DM

C −

1.2

( − 7.

5 to

5.

1)

“As

treat

ed”:

2 yr

: DM

C −

8.3

( − 13

.1

to −

3.4)

4 yr

: DM

C −

6.1

( − 12

.3

to 0

.1)

“Int

entio

n to

trea

t”:

2 yr

: DM

C 5

.9 ( −

1.8

to 1

3.5)

4 yr

: DM

C 0

.1 ( −

8.3

to 8

.4)

“As

treat

ed”:

2 yr

: DM

C 1

1.3

(5.1

to

17.

6)

4 yr

: DM

C 8

.8 (0

.6 to

16

.9)

“Int

entio

n to

trea

t”:

2 yr

: DM

C −

3.4

( − 10

.6

to 3

.9)

4 yr

: DM

C −

3.1

( − 10

.9

to 4

.8)

“As

treat

ed”:

2 yr

: DM

C 5

.1 ( −

0.8

to

11.1

)

4 yr

: DM

C 6

.9 ( −

0.7

to

14.5

)

(Con

tinue

d)





BLE

3.

(Con

tinue

d)

Stud

y

Patie

nt’s

Glo

bal A

s-se

ssm

ent*

(“G

ood

Res

ult”

) †

Pain

(“W

ith-

out P

ain”

or

“M

ild

Pain

”) ‡

Leg

Pain

§ B

ack

Pain

§ D

isab

ility

(OD

I) ¶

SF-3

6B

odily

Pai

n � SF

-36

Phys

ical

Fun

ctio

n **

Oth

er O

utco

mes

(Ran

dom

ized

co

hort—

with

out

neur

ogen

ic c

laud

i-ca

tion)

� �

“Int

entio

n to

trea

t”:

2 yr

: DM

C −

8.6

( − 20

to

2.8)

4 yr

: DM

C 4

.2 ( −

8.1

to

16.5

)

“As

treat

ed”:

2 yr

: DM

C −

8.1

( − 17

.2

to 0

.9)

4 yr

: DM

C −

8.8

( − 20

.2

to 2

.7)

“Int

entio

n to

trea

t”:

2 yr

: DM

C 1

4.9

(0.1

to

29.

7)

4 yr

: DM

C 2

(�13

.9

to 1

7.9)

“As

treat

ed”:

2 yr

: DM

C 1

3.7

(2.3

to

25.

2)

4 yr

: DM

C 1

8.7

(4.5

to

33)

“Int

entio

n to

trea

t”:

2 yr

: DM

C 1

1.6

( − 2.

4 to

25.

6)

4 yr

: DM

C −

4.5

( − 19

.5

to 1

0.5)

“As

treat

ed”:

2 yr

: DM

C 1

1.4

(0.5

to

22.2

)

4 yr

: DM

C 1

1.8

( − 1.

6 to

25.

3)

Wei

nste

in e

t al 26

“I

nten

tion

to tr

eat”

:“I

nten

tion

to tr

eat”

:“I

nten

tion

to tr

eat”

:Sa

me

as in

Wei

nste

in et

al 25

(R

ando

miz

ed c

o-ho

rt—al

l)2

yr: D

MC

− 3.

5 ( −

8.7

to

1.7)

2 yr

: DM

C 7

.8 (1

.5 to

14

.1)

2 yr

: DM

C 0

.1 ( −

6.4

to 6

.5)

“As

treat

ed”:

“As

treat

ed”:

“As

treat

ed”:

2 yr

: �8.

7 ( −

13.3

to −

4.0)

2 yr

: 11.

7 (6

.2 to

17.

2)2

yr: 8

.1 (2

.8 to

13.

5)

(Ran

dom

ized

co

hort—

with

ne

urog

enic

cl

audi

catio

n)� �

“Int

entio

n to

trea

t”:

“Int

entio

n to

trea

t”:

“Int

entio

n to

trea

t”:

2 yr

: DM

C +

1.1

( − 3.

9 to

6)

2 yr

: DM

C 2

( − 4.

6 to

8.7

)2

yr: D

MC

3.2

( − 2.

9 to

9.2

)

4 yr

: DM

C +

− 3.

7 ( −

1.6

to 9

.0)

4 yr

: DM

C −

3.6

( − 10

.8 to

3.5

)4

yr: D

MC

− 3

( − 9.

6 to

3.5

)

“As

treat

ed”:

“As

treat

ed”:

“As

treat

ed”:

2 yr

: DM

C −

16.8

( − 20

.9

to −

12.6

)2

yr: D

MC

20

(14.

3 to

25.

6)2

yr: D

MC

17.

9 (1

2.6

to 2

3.3)

4 yr

: DM

C −

18.4

( − 23

.3

to −

13.5

)4

yr: D

MC

20.

6 (1

3.9

to 2

7.3)

4 yr

: DM

C 2

0.4

(14.

1 to

26.

8)

(Ran

dom

ized

co

hort—

with

-ou

t neu

roge

nic

clau

dica

tion)

� �

“Int

entio

n to

trea

t”:

“Int

entio

n to

trea

t”:

“Int

entio

n to

trea

t”:

(Con

tinue

d)





BLE

3.

(Con

tinue

d)

Stud

y

Patie

nt’s

Glo

bal A

s-se

ssm

ent*

(“G

ood

Res

ult”

) †

Pain

(“W

ith-

out P

ain”

or

“M

ild

Pain

”) ‡

Leg

Pain

§ B

ack

Pain

§ D

isab

ility

(OD

I) ¶

SF-3

6B

odily

Pai

n � SF

-36

Phys

ical

Fun

ctio

n **

Oth

er O

utco

mes

2 yr

: DM

C 6

.7 ( −

5.6

to

18.9

)2

yr: D

MC

− 2.

3 ( −

18.5

to 1

3.9)

2 yr

: DM

C −

1.9

( − 16

.7

to 1

2.8)

4 yr

: DM

C 5

.7 ( −

7.6

to

19.0

)4

yr: D

MC

9.3

( − 8.

7 to

27.

4)4

yr: D

MC

− 2.

8 ( −

19.3

to

13.

7)

“As

treat

ed”:

“As

treat

ed”:

As

treat

ed”:

2 yr

: DM

C −

12.9

( − 21

.8 to

−

4.1)

2 yr

: DM

C 1

6.3

(4.5

to 2

8.1)

2 yr

: DM

C 8

.1 ( −

3.1

to

19.2

)

4 yr

: DM

C −

10.2

( − 21

.2

to 0

.8)

4 yr

: DM

C 1

.9 ( −

13.2

to

17)

4 yr

: DM

C 1

8.9

(4.7

to

33.1

)

Zuc

herm

an e

t al 27

20

052

yr: 7

3.1%

(s

urge

ry) v

s.

35.9

% (c

ontr

ol)

( P <

0.0

01)

Sym

ptom

s Se

verit

y Sc

ore ††

Surg

ery

bett

er a

t 6 w

k,6

mo,

1 a

nd 2

yr

(gra

phs)

( P

< 0

.001

)

2 yr

: MPC

45.

4% (s

urge

ry)

vs . 7

.4%

(con

trol

) ( P

<

0.00

1)

“Clin

ical

ly re

leva

nt im

-pr

ovem

ent (

patie

nts)

”:

2 yr

: 60.

2% (s

urge

ry) v

s .

18.5

% (c

ontr

ol)

( P <

0.0

01)

Sym

ptom

s Se

verit

y Sc

ore ††

Surg

ery

bett

er a

t 6 w

k,6

mo,

1 a

nd 2

yr

(gra

phs)

( P

< 0

.001

)

2 yr

: MPC

44.

3% (s

urge

ry)

vs . −

0.4%

(con

trol

) ( P

< 0

.001

)

“Clin

ical

ly re

leva

nt

impr

ovem

ent (

as m

easu

red

by p

atie

nts)

”:

2 yr

: 57%

(sur

gery

) vs .

14

.8%

(con

trol

) ( P

<

0.00

1)

(Con

tinue

d)





BLE

3.

(Con

tinue

d)

Stud

y

Patie

nt’s

Glo

bal A

s-se

ssm

ent*

(“G

ood

Res

ult”

) †

Pain

(“W

ith-

out P

ain”

or

“M

ild

Pain

”) ‡

Leg

Pain

§ B

ack

Pain

§ D

isab

ility

(OD

I) ¶

SF-3

6B

odily

Pai

n � SF

-36

Phys

ical

Fun

ctio

n **

Oth

er O

utco

mes

ZC

Q §§

(glo

bal s

ucce

ss) ¶

¶

6 m

o: 5

2% (s

urge

ry) v

s .

9% (c

ontro

l) ( P

val

ue n

ot

repo

rted)

1 yr

: 59%

vs .

12%

( P v

alue

no

t rep

orte

d)

2 yr

: 48.

4% (s

urge

ry)

vs . 4

.9%

(con

trol

) ( P

<

0.00

1)

Qua

lity

of li

fe (S

F-36

)

At a

ll po

st-t

reat

men

t tim

e po

ints

(6 w

k, 6

mo,

1 y

r, an

d 2

yr),

the

mea

n do

-m

ain

scor

es d

ocum

ente

d in

the

X S

TOP

grou

p w

ere

sign

ifi ca

ntly

gre

ater

than

th

ose

in th

e no

nope

rativ

e gr

oup,

with

the

exce

p-tio

n of

the

mea

n G

ener

al

Hea

lth, R

ole

Emot

iona

l, an

d M

enta

l Com

pone

nt

Sum

mar

y sc

ores

at 2

yr

(Sub

grou

p w

ith s

pon-

dylo

listh

esis

)Pa

tient

s sa

tis-

fact

ion

(ZC

Q

dom

ain)

: ‡‡

2 yr

: Bet

ter

surg

ery

(sta

tisti-

cally

sig

nifi c

ant)

(gra

phs)

Sym

ptom

s Se

verit

y Sc

ore ††

2 yr

: Bet

ter

surg

ery

( P <

0.

0001

)

Sym

ptom

s Se

verit

y Sc

ore ††

2 yr

: Bet

ter

surg

ery

( P <

0.

0001

)

ZC

Q §

§ (gl

obal

suc

cess

) ¶¶

2 yr

: 63.

4% (s

urge

ry) v

s .

12.9

% (c

ontr

ol) (

“hig

hly

stat

istic

ally

sig

nifi

cant

”)

(Con

tinue

d)





TAB

LE 3

. (C

ontin

ued)

Stud

y

Patie

nt’s

Glo

bal A

s-se

ssm

ent*

(“G

ood

Res

ult”

) †

Pain

(“W

ith-

out P

ain”

or

“M

ild

Pain

”) ‡

Leg

Pain

§ B

ack

Pain

§ D

isab

ility

(OD

I) ¶

SF-3

6B

odily

Pai

n � SF

-36

Phys

ical

Fun

ctio

n **

Oth

er O

utco

mes

* The

pat

ient

s w

ere

aske

d to

eva

luat

e th

eir

own

situ

atio

n an

d to

sta

te w

heth

er it

was

bet

ter,

wor

se, o

r un

chan

ged

as c

ompa

red

with

thei

r co

nditi

on o

n en

terin

g th

e st

udy.

Thi

s, to

geth

er w

ith th

e op

inio

n of

the

exam

-in

ing

phys

icia

n, c

onst

itute

d th

e ba

sis

for

the

stat

emen

t of o

vera

ll tr

eatm

ent r

esul

t (ex

celle

nt, f

air,

unch

ange

d, a

nd w

orse

).

† Exc

elle

nt (

full

or a

lmos

t ful

l res

titut

ion

cons

ider

ing

pain

and

phy

sica

l fun

ctio

n) o

r fa

ir (p

artia

l res

titut

ion

with

less

er p

robl

ems

and

clea

r im

prov

emen

t ove

r th

e co

nditi

on a

t ent

ry to

the

stud

y) w

as c

onsi

dere

d to

be

a go

od r

esul

t.

‡ The

inte

nsity

of p

ain

was

sta

ted

verb

ally

(se

vere

, mod

erat

e, o

r lig

ht).

§ The

inte

nsity

of p

ain

was

ass

esse

d by

a N

umer

ical

Rat

ing

Scal

e (0

, no

pain

to 1

0, w

orst

pos

sibl

e pa

in).

¶ O

swes

try

Dis

abili

ty In

dex,

whe

re 0

indi

cate

s no

dis

abili

ty a

nd 1

00 in

dica

tes

wor

st p

ossi

ble

disa

bilit

y. W

eins

tein

, 200

7 an

d 20

08, e

xpre

ssed

the

resu

lts a

s th

e pe

rcen

tage

of t

he m

axim

um s

core

.

� SF-

36 H

ealth

Sta

tus

Que

stio

nnai

re (

phys

ical

func

tion

subs

cale

), w

here

hig

her

scor

es in

dica

te b

ette

r ou

tcom

es.

** SF

-36

Hea

lth S

tatu

s Q

uest

ionn

aire

(pa

in s

ubsc

ale)

, whe

re h

ighe

r sc

ores

indi

cate

bet

ter

outc

omes

.

†† A

dom

ain

of th

e Z

CQ

(1–

4), w

here

1 is

the

best

pos

sibl

e ou

tcom

e an

d re

pres

ents

no

pain

.

‡‡ A

dom

ain

of th

e Z

CQ

(1–

5), w

here

1 is

the

best

pos

sibl

e ou

tcom

e an

d re

pres

ents

no

limita

tion

in fu

nctio

n.

§§ Z

uric

h C

laud

icat

ion

Que

stio

nnai

re (

capt

ures

dat

a in

thre

e di

stin

ct d

omai

ns:

sym

ptom

sev

erity

; ph

ysic

al fu

nctio

n; a

nd p

ost-t

reat

men

t pat

ient

sat

isfa

ctio

n) (

3–13

), w

here

3 is

the

best

pos

sibl

e ou

tcom

e.

¶¶ Tr

eatm

ent i

s co

nsid

ered

suc

cess

ful i

f the

pat

ient

is a

t lea

st “

som

ewha

t sat

isfi e

d” (

an a

vera

ge s

core

of 2

.5)

and

has

at le

ast a

0.5

impr

ovem

ent i

n bo

th s

ympt

om s

ever

ity a

nd p

hysi

cal f

unct

ion.

� � D

ata

prov

ided

by

the

auth

ors

at r

eque

st (

not p

ublis

hed)

.

*** W

alki

ng c

apac

ity w

as a

sses

sed

on a

trea

dmill

at a

spe

ed o

f 2.5

km

/h fo

r a

max

imum

of 3

0 m

in o

r 1.

25 k

m. R

estr

ictio

n of

wal

king

was

defi

ned

as

the

dist

ance

afte

r w

hich

a p

atie

nt d

id n

ot w

ant t

o go

on

beca

use

of p

ain,

or

fatig

ue o

r w

eakn

ess

in le

gs, o

r a

com

bina

tion

of th

ese.

36-it

em M

edic

al O

utco

mes

Stu

dy S

hort

-For

m G

ener

al H

ealth

Sur

vey

DM

C in

dica

tes

diffe

renc

es in

mea

n ch

ange

s fr

om b

asel

ine

(with

95%

con

fi den

ce in

terv

al);

MD

, mea

n di

ffere

nce

(with

95%

con

fi den

ce in

terv

al);

MPC

, mea

n pe

rcen

tage

cha

nge

(with

95%

con

fi den

ce in

terv

al);

R

R, r

isk

ratio

(w

ith 9

5% c

onfi d

ence

inte

rval

).

Bol

d le

tters

indi

cate

the

resu

lts th

at fa

vor

surg

ery

(sig

nifi c

ant d

iffer

ence

s).





are not present, decompressive surgery could be envisaged. In patients with signifi cant spondylolisthesis, the surgeon may consider complementing decompressive surgery with nonin-strumented posterolateral fusion or with the simplest possible instrumented fusion procedure. This approach would not be suitable for patients who show spinal stenosis on imaging but are asymptomatic or report only back pain (without pain or neurological symptoms in the legs), or for those with serious neurological impairment, especially in those with cauda equina syndrome in whom surgery should be conducted urgently. 67

Generalizability of these results to clinical practice should be discussed. Care providers participating in these RCTs were volunteers as opposed to a random selection of those work-ing in the setting where the studies took place and whether their criteria and level of skills are representative of the rest of care providers in their environment is unknown. Moreover, no data are available on the learning curves necessary before application of some of the forms of treatment that were used in these studies, such as epidural injections or surgery. Educa-tion and training standards for these procedures in routine practice should match those required in these RCTs because these standards are essential for generalizability of any non-pharmacological health technology. 66 Postmarketing surveil-lance should also be implemented, ideally by setting up a registry including all patients seeking care for symptomatic spinal stenosis, minimizing losses to follow-up, and using validated methods to gather clinically relevant data (including demographic data, clinical features, comorbidities, conserva-tive and surgical treatments applied to each patient, experi-ence and training standards of the care providers applying them, and patient’s clinical evolution). 66 Such postmarketing surveillance would not substitute RCTs but would be valu-able to: (1) determine the effects in routine clinical practice, of treatments that have previously shown to be effective through RCTs, (2) compare, in routine practice conditions, the results from treatments that have shown to be effective for the same subset of patients as in previous RCTs, (3) identify factors that predict the result of each treatment to refi ne its indication criteria, and (4) gather data on unexpected safety concerns.

In conclusion, this review shows that decompressive sur-gery with or without fusion and implantation of a specifi c interspinous distraction device are more effective than con-tinued conservative treatment for radicular pain due to spi-nal stenosis in patients in whom the latter has failed for 3 to 6 months.

the largest crossover rates, most differences were statistically signifi cant only in the “as treated” analysis and not in the “intention to treat” one. 25 , 26 Moreover, blindness (of thera-pists, patients, and outcome assessors) is unfeasible in studies comparing surgical with nonsurgical procedures and the pla-cebo effect from surgery is likely to be more powerful than the one from conservative treatment, especially among patients in whom the latter has already failed. This is a special concern because outcome variables are subjective and assessed by the patients ( e.g ., pain severity, function, and satisfaction).

However, these are the variables that make clinical sense, were assessed using previously validated methods, the studies’ design was reasonable ( Table 1 ), and their limitations are inher-ent to the kind of treatments being assessed and to the patient characteristics. The only way of controlling for potential dif-ferences in the placebo effect would be to undertake RCTs comparing decompressive surgery with sham surgery, which might face ethical and practical diffi culties. Despite differences in methods and geographical settings, results from the stud-ies included in this review consistently favor surgery and are biologically plausible. All this suggests that, although method-ological weaknesses make it inappropriate to consider each of the reviewed studies as representing “the best evidence in ideal conditions,” the general conclusions from this review may be seen as deriving from “the best possible evidence in this fi eld.”

Further RCTs could also compare different surgical tech-niques in specifi c subsets of patients and should compare the interspinous device with surgery in the subset of patients in whom the former is indicated. Such a study appears to have been initiated. 65 Further RCTs could also assess the effective-ness of specifi c forms or combinations of conservative treat-ments to compare surgery with truly effective alternatives. All these studies should be of high methodological quality and conducted independently from the industry by authors with no confl icts of interest. 66 They should be designed as large multicenter trials with strategies to reduce withdrawals and crossovers. There may be ethical concerns regarding further RCTs using the same methods as those used in the studies included in this review to compare the same miscellanea of surgical and conservative treatments.

No catastrophic events ( e.g ., cauda equina syndrome) arose among the patients receiving conservative treatment. Results from surgery were similar among patients initially assigned to surgery and those who crossed over to this group after failure of the conservative treatment they had been initially assigned to. 23 , 25 , 26 This suggests that delaying surgery is not associated with a poorer prognosis. On the contrary, the interspinous implant is less aggressive and resulted in less blood loss and a shorter hospital stay than decompressive surgery (with or without fusion). Taken together, these results may counsel a step-by-step approach in the treatment of spinal stenosis. The fi rst step could be a conservative treatment for 3 to 6 months. If such an approach fails, the implantation of a specifi c type of inerspinous device should be considered in patients aged 50 years and older, with neurogenic claudication and spon-dylolisthesis of Grade I or less who are able to walk 50 feet or more and have no motor defi cit. If these indication criteria

➢ Key Points

Five high-quality randomized controlled trials (RCTs), including a total of 918 patients, compared surgi-cal procedures (the implantation of a specifi c type of interspinous distraction device or decompressive surgery, with or without fusion, whether instru-mented or not) with a miscellanea of conservative treatments, in patients with symptomatic lumbar spinal stenosis in whom the latter had failed for 3 to 6 months.





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27. Zucherman JF , Hsu KY , Hartjen CA , et al. A multicenter, prospec-tive, randomized trial evaluating the X STOP interspinous process decompression system for the treatment of neurogenic intermit-tent claudication: two-year follow-up results . Spine 2005 ; 30 ( 12 ): 1351 – 8 .

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30. Brox JI , Sorensen R , Friis A , et al. Randomized clinical trial of lum-bar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration . Spine 2003 ; 28 : 1913 – 21 .

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In all the studies, surgery led to better results for pain, disability, and quality of life, although not for walking ability. Results of surgery were similar among patients with and without spondylolisthesis, and slightly better among those with neurogenic claudi-cation than among those without it. The advantage of surgery was noticeable at 3 to 6 months and remained for up to 2 to 4 years, although at the end of that period diff erences tended to be smaller.

Main methodological concerns in these RCTs include the heterogeneity of treatments within the conser-vative and surgical groups, the fact that all patients included had unsuccessfully undergone conserva-tive treatments previously, which may have led to diff erences in the placebo eff ect across groups and increased crossover, withdrawal, and dropout rates, and the lack of blindness of care provider, patients, and outcome assessment. However, these concerns are inherent to the type of patients included and the kind of treatments compared. Therefore, evidence from these RCTs can be seen as the “best possible” in this fi eld. There may be ethical concerns regard-ing further RCTs comparing the forms of surgery and conservative treatments, which have been used in these trials.

Further RCTs should: (1) compare the interspinous device with surgery in patients aged 50 years or older, with neurogenic claudication and spondylolisthesis of Grade I and lesser, who are able to walk 50 feet or more, and have no motor defi cit; (2) compare dif-ferent surgical techniques and interspinous devices in specifi c subsets of patients; (3) defi ne indication criteria for the diff erent surgical procedures;(4) defi ne learning curves for all these procedures;(5) implement registries and postmarketing surveil-lance methods; and (6) not be conducted by the in-dustry or by authors who harbor confl icts of interest.

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