Endoscopic microsurgery in herniated

Endoscopic
microsurgery
in herniated
cervicaldiscs
AndreaFontanella
Depaftment
of Neurosurgery,
Hospital,Cittädi parma,,parma,ltalv
The purpose of this study was,jo makepublic our resultsusing endoscopic
microsurgeryin herniated
cervicaldiscs' Thistechniqueallows us to'avoid complicationsaä to iirr"ntional
expoiur|, as is thtecase
in traditionalapproaches.
T!,is.study
wa.scarriedou.t'from
Januarytggl-io'i"rr^ry | 99g.one hundred and
seventy-onepatientsshould have undergonetraditionaltyrgui for 296
herniatedcervicaldisls. They
were, instead, treated bLu:,ng endoscöpic.microsu.rgica!
iurhniqrii tn 223 herniationsthe surgical
procedurewaspefformedby a iaramidlin'e right anteriir approach,änd
in 23 herniatiotnts
iy ^'p,iu-Äiatir"
posteriorapproach,with a workingsleeveof 2.6 mm outer äiametörin
boti cases.ln theuit*'[o, ipprourn
the tu,be
firmlyplaced
anteriorlongituctinat
ligaÄ"it ^rlit'n" edgeof the anteriorpili of the
,was
lsains{1he
vertebralbodies. The neurovascular
structureswdre placed"lat"ru!i tni iorling sleeveand th" iirr"rrl
structureswereplacedmedialto the,workingsleeve.'Then,under endoscopic
ciaxial.contro!,removalof
the herniatedpaft.w1speiormed, through ihe intervertebraldiscs,with mlicrosurgical
instruments.
ln the
posteriorapproach,the tu.be.wasplac.edinstead
between theinferior andsuperior lamina,thenunder the
nerve root up to the herniation,which was removecl.This posteriorapproac'h
was usedonly in ti"-iut"ral
disc herniations'Therewere^1o-jlcidgnts.ormaior
räitoiing theseoperations.After one
.cöm-plications
month the successrate was 94.7%, afterthree monthsgi.sr, aftersix ^init,, ga.q,i"
ani afte,ir" y.u,
97%' Therewereno caseso.f,relapse
during thefollow-up p"i"i ir tnite'"patients.rni, stiay sigj"rt, tt,"t
for herniatedcervicaldiscs, the.eÄdoscopiä
microsurgicu't
i"in:,i,quu'ii {i,u-"ty
advantageous
and safe
method. M9reoy9r, tonger fotlow-.upperiods and-an increasädnu^aui
"i
ä;;;-,üiin
,ni,
procedureshouldfurtherconfirm the u'sefulness
"i'p;;r;;;;
of this techniqr".fNi;r;i Res
1999;21: 31-3Bl
Keywords:Cervical vertebrae;intervertebra!disk displacement;
ntyelopathy; spine; neurosurgical
treatment;endoscopy
INTRODUCTION
Cervicalmyelopathyand/or cervical radiculooathv
causedby compressive
lesionsfrom herniatedcervicjl
hal been surgicallytreatedeither by a posterior
ltsc.
laminectomy
or by an anteriorapproachwith oi without
Interbodyfusion.The posteriorapproachwas first
oes '?ed in 1950 by Spurlingand Scovillerto lreat
prtmarily
laterally
displaced
discherniation.
lt hasbeen
used less frequentlysince the developmentof
the
anterior.
approac.h
to the cervicalspine2?.positioning
n"1i"1'tin, the prone position,the complication!
l!1,
assocrated
with posteriorapproachincludenerveroot
prrtjgularlywhen morethanone rooris exposed,
11111,
injurysecondarv
to cord retraction,
particuilj,l.ul,.old
larl) during.transduralapproachto a herniated
disc,
sprn.' instability,particularly.
when the facet joint is
posteriormuscletraumaand injury.For
IlTi""9,_i"d
past30 years,the anteriorapproachhas'betome
:ne
very popular.Threeco^mmon
techhiquesof fusionare
oescribed,
by,Clowa,rd2,s,u,
Baileyand Badgleyr,;;
)mrtnand Robinsona.
In Cloward,s
tOSapLibliäation2,
hedescribed
hisoperative
techniquL.
i-,e cämplicationi
associated
with thä anteriorapproachi".f rJ" injuriesto
llrrespondence "
reracani
12, 431ooparma,ttaly.Ä..uptJ for'frbl;r;;"
sh
ingcrouP
EJ,'1'.
i3Än1'rä:iri
April 1998.
the spinal cord, the nerve roots7,8,the veftebral artery,
the sympathetic chain and the anterior soft tissue
s t r u c t u r e s ,s u c h a s t h e e s o p h a g u s , c a r o t i d a r t e r y ,
recu.rrent
llr.h:9,
.laryngeal nerve änd, very rarely, the
thyroid gland. Wirh rhe anterior approach at the ör_T,
level, injury to the dome of the öärietal pleura of the
l u n g w i t h s e c o n d a r yp n e u m o t h o i a xi s a b o s s i b l er i s k .
When fusion is performed, in the immediate Dost_
operative period, graft extrusion should oc.urn. öser_
doaft.hrosis
may be presentafter a one-segmentfusion,
but this d_oesnot necessarilypreclude a äood clinical
outcomelo'1t.Other compliiations, typicaiof the fusion
with au.tograft,
are representedby the'ihjuryto the lateral
femoralcutaneousnerve, hematoma,iliac wing fracture
and post-operativewound infection10,l2.
When"allograft
is used to make the fusion, transmissionof communicable diseasesis possible.
When fusion is performed, the inevitable stresses
applied to adjacent interspaces are present. This
increasesthe probability of disc herniätions and/or
degenerative changes in the adjacent interspaces.
Kyphotic deformity, developing long-termsecond'aryto
an anteriorcervical discectomy with or without fusion.
may be present. Scar tissue formation in the cervicai
s p i n a lc a n a l a n d / o r i n t h e f o r a m i n am a y d e v e l o p i n a l l
t h e c e r v i c a l s p i n a l s u r g e r y a n d p a r t i c u l a r l yi n t h e
posterior approach. Taking into considerati'onthese
Neurological Research, | 999, Volume 2l , Januarv 31
Endoscopic
A
.l:
Figure
During surgery, in the AA, the patient is placed in the supine position. A: Anterior part of the neck with an
anterior posteriorprojection of the ceruical spine; the midline and the level of the disc herniation has ben drawn on the
skin. 8: Lateral view of the patient on the operating table. A pillow is placed under the patient's neck to maintain
physiological cervical lordosisand the patient's face is kept straight.A blunt obturator can be seen firmly placed against
the anterior longitudinal ligament and the edge of the anterior part of the adjacent vertebral bodies, at the appropriate
interuertebrallevel
Figure 2: A trephine is insertedin the working sleeve and carefully advanced in intervertebralspäce up to the herniation.
In these fluoroscopic views it is possible to see A: an anterior posterior projection and B: a lateral projection of the
ceruical spine with the working sleeve and the trephine
complicationsand thä outcomes in the open spinal
surgery,we used 'closed' surgical techniques.With
minimally invasivespinal neurosurgerythe trauma for
the patient in the surgical area is minimised, and
r.
consequentlyiatrogenicöffectsmay be avoidedl These
of many
closedtechniquestook risefrom the association
different procedures used in neurosurgery.Stereotaxy
was the first step towards minimally invasive neurothe introductionof the operating
surgery.Subsequently,
microscopepermittedreduction of surgicalfield with
consequentimprovementof surgicaltechniques,to the
patient's benefit. Furthermore, the development of
'neuroimaging
methods'like CT and MRl, revolutionised
32
Neurological Research,1999, Volume 21, January
neuroradiologic
diagnostics,permittingprecisesurgical
programming.The use
planningand three-dimensional
of the computer applied to surgery, the so called
'neuronavigator'has yielded high precision surgical
techniques,and can be linked with very sophisticated
control systems, such as intra-operativeechography,
intra-operativeCT or intra-operativeMRl, to achievethe
optimum therapeuticeffectwith the minimum surgical
trauma. More recently,endoscopes,i.e. optic instruimagesfrom one placeto
mentscapableof transferring
another(froman areainsidethe body to the outside)and
linked with microcamerasystems,have been considerably improved and allowed the beginning of the
Endoscopic microsurgery in herniated certical discs: Andrea Fontanella
Figure 3: Schematic drawings of the anatomy of
the neck in axial section.
A: A trephine inserted in
the working sleeve up to
the herniation.B: The
m i c r o e n d o s c o p i cc a n u l a
inserted in the tube with
an angled microforceps
removing the hcrniated
part
Figure 4 A: Fluoroscopic view of microforceps
removing the herniation. B: The microforceps
in use
usedto separatethe
Figure5 A: Microscissors
dural sheathfrom the underlyingherniatedpart
in
and reactiveadhesions.B: The microscissors
use
B
Neurological Research,1999, Volume 21, January 33
Endoscopic microsurgery in herniated ceruical discs: Andrea Fontanella
of the operation with somatosensoryand motor evoke
potentialsmay be helpful.All the operativetechnique
must be followed carefully,step by step'The operatin
surgeonmust be properlylrained in theseendoscop
tecEniques.In the'PA the patientis placedin the pron
oositioÄon the operatingtable with the neck slight
ilexed. Beforemakine a skin incision,a lateralfluorc
scopic image should be obtained to verify the exa<
intervertebällevel.Then,a very smallincision,lesstha
5 mm long, is made over the ligamentumflavum at th
.orru.t uött"bral space, in paiamidlinearea'.A blur
obturatoris introducedfirst in dorsalfascia,and then, i
p a r a s p i n a lm u s c l e s u p t o t h e l i g a m e n t u mf l a v u n
Successivelythe working sleeve is - introduced an
r t reaches th
until
t r t r r it
g u lided
ogo
obturator
()l'uldtul u
blunt
lunI o
bv'the
D
y Ine D
igamentum flavum, which. is passedusing a sma
täphine passing through the working sleeve' The
,rins u fine bllnt instiument, palpation beneath tl'
nervä root is done from both above and below, undr
endoscopic control, which is obtained by a microend
scopicrigid or flexiblecanula,previouslyinsertedin tf
M A T E R I A LA
SN D M E T H O D S
Bleedingfrom epidural veins can I
*oiking'.un"l.
to
1991
from
out
January
This studywas carried
January
'l
tiny cofton pledgets.During surge
with
controlled
998. One hundred and seventy-onepatientsshould
irrigationand suctionin the operatingfield are achiev
have undergonetraditionalsurgery for 296 herniated
by"suitable microinstruments.A bipolar coagulat
cervical disis. All patientshad symptomsof cervical
microelectrodemust be available, if required. lt
myelopathyand/or'radiculopathy.They were, instead,
important not to cause pressureon the dural shea
techmicrosurgical
endoscopic
the
using
by
treated
the dural slee
in separating
anä grealcare is necessary
surgical
the
niques.ln 148 pätientswith 273 herniations,
of thä nerveroot from the underlyingherniateddisc ar
by a paramidlinerightanterior
procedurewas.performed
reactive adhesions (Figure 5. The nerve root is th(
approach(AA, while in 23 patientswith 23 herniations
(
P
A
)
.
retracted superiorly (Sometimesinferiorly),thus tl
Preby a paramidline posterior approach
herniated part can be removed using different micr
magnetic
and
plain
films
had
patients
all
operatively
instruments,such as microforceps (Figure 4), micr
(Figures
(MRt)
the
and
104)
BA,
resonance imaging
scissors (Figure 5, microknives of different shap
palientswith böny changeshad computedtomography
microprobei Gieure 6i),microhooks,and microresecto
associated
without
with
or
9A)
iCT) r.unr Gigure
It is important tö verify that the nerve root is complete
17i
myelography (mielo-CT). Ninety-eight of these
decombressedand mobile by following the nerve rc
oatientsweie males, while 73 were females.Average
out latörallyand medially,
'6)using microhooksgradua
age was 45 years. The youngest subject was 16-yearsin different'ways(Figure andluitable flexibleor ri1
o"ld and the oldest was B5-years-old.Six patients had
endoscope. In this phase, delicate movements ;
four herniations,27 patientshad three, 53 patients had
required to avoid iniury to the nerve root and to t
herniated
two, while 85 had only one herniation.The
usingendosco
duial column. A drain is not necessary
cervical disc was at the C2-C3 level in four cases,at the
is placed in t
patient
the
AA
In
the
microsurgery.
in
56.cases,
level
at
the
Ca-C5
cases,
C3-Calevel in 28
the neck
under
pillow
pLaced
päsiiion,
is
a
supine
91
aithe C5-C6 level in 99 cases,at the C6-C7 level in
rnäintain physiologicalcervical lordosis,and the ;
cases,and at the C1T1 level in 1B cases.Thesesurgical
tient's face is keptitraight Gigure lB). The arms sho
techniques were studied and practised over a long
be placedat the iide, pülled distallyand held in place
period bf time on cadavers,before they were applied to
facilitatepositioningof the surgeonand obtainingint
was
there
herniation
disc
in
cervical
When
care.
batient
operative fluoroscöpic imagei. The midline and t
neuprogressive
iailure of nonoperativemanagement,
level of the herniationare then drawn
intervertebral
rologicaldeficit or myelopathy,operative.intervention
the
neck under fluoroscopiccontrol (Frg
of
skin
the
the
patients
in
included
were
these
was*considered:
incision,lessthan five millimeter
very
small
A
1A).
Dresentstudv. We used for the first time endoscopic
made vertically at the correct intervertebralsPace,
*icrosrrgetf with posteriorapproach for far lateral disc
the right side, about 15mm from the midline. I
herniatioäwhen there was no imbricationof adiacent
platvsäamuscleis also incisedin the entirewidth of
with anterior
lamina.We usedendoscopicmicrosurgery
skin'incision.A blunt obturator(FigureI B), is introdu
were
we
years
recent
In
cases.
other
in
the
aoproach
throughthe skin and the platysmamuscle.Afterincis
ln
both
iÄilined to use insteadonly anteriorapproach'
of the pre-trachealfascia,which is.ope.nedjust.ante
techniques we administered prophylactic.antibiotic
muscle, the subplaty
to the sternocleidomastoid
under.general
performed
was
treatment and surgery
a blunt obturator
Using
done.
can
be
dissection
endotrachealanesthesia,sometimesin neÜroleptanstrap muscles, the trachea and the esophagus
In somecases,monitoring
algesiawith local anesthesia.
endoscopic microneurosurgery'Following this.philosophy,k'eyholesurgerywas-developed.This technique
enabiedthe surgeoäto reach the surgicaltargetthrough
stereotaxic method, and perform the intervention by
meansof endoscopicsystemsr-rsingparticular.probes,
'working sleeves"'. Our personalexperlthe so-called
beganin 1989
ence in the field of keyholeneurosurgery
and we introducedthistechniquein the cervicalspinein
approachor, less
January1991, using either anterior
o.
irequently, posterio'r approachl Endoscopic microallows us to easily reach and exposethe
neurosurgery
which can be removedwith greatfacility,
herniated"part
thus reducing the risk of complications.With this
pos!
technioue
ii possible
oossibleto avoid Ithe formationof post
techniqueit is
operativescar tissueand secondaryiatrogenicevents,
such as rerlehral instabilily.Thereforeinterbodyfusion
is not required and, thus, the patient is immediately
mobiliseda{tersurgery.
, r , , ' : i,i
i:-t :f r i .
:T:;l-:
34
Neurological Research,1999, Volume 21, January
tndoscopic microsurgery in lrcrniated cervical discs: Anclrca ['ontanella
Figure 6A: Fluoroscopic view of microprobe angled at 45 degreesused to verify that the nerve root and spinal cord are
completely decompressedand mobile. In this phase, delicate movementsare required to avoid injury to the spinal cord,
the nerve root and the dural sheath. B: The microorobe in use
retractedmedially,while carotid sheath is held laterally.
The working sleeveis then introducedand guided by the
blunt obturator until it reachesthe or€vertebrälfascia.
rvhich is openedby a small microknlvä At this point the
o r k i n gc a n a l i s p l a c e da g a i n s t h e a n t e r i o rl o n g i t u d i n a l
, , g a m e nat n d t h e e d g eo f t h e a n t e r i o rp a r t o f t h e a dj a c e n t
vertebral bodies. An appropriate sized trephine is
insertedin the working sleeve and carefully advanced
in intervertebralspace up to the herniation (Figures2
a n d - l A ) . U s i n g a m i c r o e n d o s c o p i cr i g i d o r f l e x i b l e
canulafor endoscopiccontrol, the herniatedpart can be
removed (Figure3B). Many instrumentsmay be used,
rch as various types of microforceps, for example
irpwards,downwards, straight (Figure 4), and flexible,
severaltypes of microknives, microscissors(Figure 5,
microprobes(Figure 6) and microhooks, with different
angulations,and variousmicroresectors.During surgery,
as well as PA, irrigation and suction in the operating
field are necessaryand a bipolar microelectrodemust be
availablel3.No ionclusive evidence exists for removal
oi all osteophytesfrom the posterior part of vertebral
, :iy or_ for removal of the posterior longitudinal
ligamentl0,ls-22.We believe that it is important to
remove only the part of the osteophytes'which is
compressingthe nerve root and/or the spinal cord. A
s m a l la n d l e n g t h e n e dh i g h - s p e e d r i l l w i t h d i a m o n d b i t
and curettesof different sizes and shapes, are used to
removeosteophytes.The drain is not used. The patient
can be up 20 h aftersurgeryand be dischargedwithin a
'j
v o r t w o . H e i s p l a c e di n a c e r v i c a lc o l l a r w h e n h e i s
ii;i in bed, for four weeks after surgery. Activities are
l i m i t e di n t h e f i r s tw e e k s .T h e r e i s a f u l l r e s u m p t i g no f
a c t i v i t i e si,n c l u d i n gw o r k , w i t h i n f o u r w e e k s .
RESULTS
In this study we consideredsuccessas the disappearance or the improvementof patient'srynptoms, such as
m y e l o p a t h y ,r a d i c u l o p a t h yo r n e c k p a i n . I n o u r s t u d y
t h e r ew e r e n e i t h e ri n c i d e n t sd u r i n g s u r g e r y ,n o r m a j o r
c o m p l i c a t i o n sf o l l o w i n gt h e s eo p e r a t i o n sT. h e p e r i o do f
f o l l o w - u pr a n g e df r o m 1 2 m o n t h st o 8 4 m o n t h s .P a t i e n t s
w e r e e x a m i n e do n e m o n t h , t h r e e m o n t h s . s i x m o n t h s
and one year after surgery,and thereafteron a yearlv
b a s i s .N o p a t i e n te x p e r i e n c e dr e l a p s ef o l l o w i n g o p e r a tion in this study period. After one month the success
rate was 94.7% (162 of the 17'l patients),after three
m o n t h s9 5 . 9 % ( 1 6 4 o f 1 7 1 ) ,a f t e rs i x m o n t h s9 6 A % ( 1 6 5
of 171), after one year 97.0o/o(166 of 171\ (Figure 7\.
We saw the same resultsafter a period of longer than
one year. In this study there were three patientswith a
large and lateral herniation compressingthe vertebral
artery. In these three patients the symptoms correlated
with vertebral artery compression disappeared after
surgery.In our seriesof patients disc space narrowing
was not presentin the subsequentradiographsof all the
casesoperated either with AA or PA. In the dynamic
v i e w r a d i o g r a p h s ,t h e m o b i l i t y o f c e r v i c a l s p i n e i n
flexion,extensionand in lateralbending was completely
preserved,as with previous surgery. Kyphotic changes
were never noted in the time using this endoscopic
microsurgery.The MRI and CT post-operativecontrols
demonstrateda comolete removal of the herniations
(Figures8-10).
DISCUSSION
AND CONCLUSION
T h i s s t u d ys u g g e s t tsh a t f o r h e r n i a t e dc e r v i c a ld i s c s ,t h e
e n d o s c o p i c m i c r o s u r g i c a lt e c h n i q u e i s a n e x t r e m e l y
Neurological Research, 1999, Volume 2l, lanuary
35
Endoscopic microsurgery in herniated cervical discs: Andrea Fontanella
Figure 7: Changes over time in successrates (green) and failuie iutei (r"dl in the present study. After one month the
s u c c c s s r a t e w a s g 4 . T " ß ( 1 6 2 o f t h e 1 7p1a t i e n t s ) , a f t e r t h r e e m o n t h s 9 5 . 9 7 . ( 1 6 a
1o
7 f1 ) , a f t e r s i x m o n t h s 9 6 . a % ( 1 6 5 o (
1 7 1 ) ,a f t e ro n c y e a r 9 7 . O % ( 1 6 6 o f 1 7 ' l) . W c s a w t h e s a m e r c s u l t sa f t e r p c r i o d s o f l o n g e r t h a n o n e y e a r
A
B
F i g u r e I A : M R I v i e w o f a p a t i e n t w i t h a d i s c h e r n i a t i o na t C s - C 6 l e v e l . B : P o s t - o p e r a t i v e
MRI confirmsa complete
removal of the herniated part
36
Neurological Research,1999, Volume 21, January
Endoscopicmicrosurgery in hcrniated cervical discs: Andrea Fontanella
I
I
.:i'::,
F i g u r e9 A : C I v i e w c r fa p a t i e n tw i t h a d i s c h e r n i a t i o na t C s - C 6 l e v e l .B : P o s t , o p c r a t i v C
e T s c a nd e m o n s t r a t eas c o n r p l e t e
removal of the herniation
A
F i g u r e ^ 1 0 ^ A : MvRi e
l wofapatientwithtwolargeektrudedfragmentsofdischerniationattheCo
C 5 l e v e la n d t h e C 5 - c 6
l e v e l . B : P o s t - o p e r a t i vM
e R r s h o w sa w h o l e r e m o v a lo f t h e d i s c h e r n i a t i o n s
N e u r o l o g i c a l R e s e a r c h ,1 9 9 9 , V o l u m e 2 1 , J a n u a r y ) 7
Endoscopicnticrosurgeryin herniated cervical discs: Andrea Fontanella
advantageousand safe methodla'1s.The goal of ttris
surgical"techniquewas to achieve direct and effective
ana"tomica!cleiompressionof the spinal cord and/or
nerve root and/or v'ertebralartery, without fusion of the
adiacent vertebral bodies and without post-operative
imkobilisation by maintenance of integral spinal
stabilitvW
. i t h t h i s ' e n d o s c o p i ct e c h n i q u ei t i s p o s s i b l e
t o m a i n t a i n a n o r m a l m o b i l i t y o f i n t e r v e r t e b r asl p a c e ,
avoidine the inevitable stressesapplied to adiacent
interspaiesfollowing fusion and the consequent secondary morbidity. Following this keyhole surgery,
complications are very improbable and there are no
iutroiuni. changesseiondary to the surgery' In all the
oatielntswe dii not remove most of the disc in the
intervertebralspace, which maintains spinal stability'
This technique'allow us to operate on several levels of
t h e c e r v i c a ls p i n ea t t h e s a m e t i m e . T h e o p e r a t i o nt i m e
o f t h i se n d o s i o p i ct e c h n i q u ci s s i g n i f i c a n t l sy h o r l e rt h a n
i n t h e o p e n t r a d i t i o n a l t e c h n i q - u e sA- v e r a g e t i m e i n
endoscopic microsurgeryto. perform a. standardherniec[omy was 25 min. iomprehensive training in this kind
of surg'eryis necessarybefore performingoperations'We
tf
t h i n k i h a t c o n t i n u e dd e v e l o p m e n ta n d i m p r o v e m e n o
instruments,longer folloiv-up periods and a greater
n u m b e r o f p a t i e n t st r e a t e d ,w i l l f u r t h e r c o n f i r m t h i s
e n r l o s c o p i cm i c r o s u r g i c atle c h n i q u e r a .
REFERENCES
I Spurling R, Scoville W. Lateräl rupture of the cervical intervertebral
d i s c s .S u t g C y n e c o l O b s t e t 1 9 4 4 ; 7 8 : 3 5 0
2 C l o w a r d i . T h e a n t e r i o ra p p r o a c h f o r r e m o v a l o f r u p t u r e dc e r v i c a l
drscs./ Necrrosurg1958; 15: 602
3 B a i l e y R , B a d g l e / C . S t a b i l i z a t i o no f t h e c e r v i c a l s p i n e b y a n t e r i o r
f u s i o n ./ B o n eJ o i n t S u r g 1 9 6 O ; 4 2 A : 5 6 5
4 Smith C, Robinson R. Tlre treatmentof certain cervical spine
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tor
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