Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6051_Библиотеки_им_академика_М_И_Перельмана
.pdf
Fig.3.6a–eLongcassettestanding(a)lateraland(b)sagittalCTreconstructionofa67-year-oldmanwhounderwenta
previousanteriorandposteriorL2-L4fusionforanL3burstfracture.Intraoperativeviewswith(c)thetemporarycentral
rod in place and postoperative long cassette (d) lateral and (e) sagittal T2 magnetic resonance imaging (MRI)
demonstratingrestoredsagittalalignmentfollowinganL3PSOandT10topelvisconstruct.
For thoracic-level osteotomies, the transverse processes are removed to reveal the
medial rib. The rib is dissected free from all its soft tissue attachments, taking care to
avoidentering thepleuralspace. Theribis thencut5 to6 cmlateralfrom thevertebra.
Subperiostealdissectionisdonetofreeupthemedialrib,whichisthendetachedfromthe
lateralaspectofthe vertebralbody.Dissectionalongthelateralpedicle andbodyisthen
performedtofree themediastinumfromtheventralvertebralbody.Spoonretractors can
then beplaced around theanterior vertebratofurther protectthe mediastinal structures.
Retracting the spinal cord should be avoided during the decompression to minimize
iatrogenicinjury.
MinimizingBleedingDuringtheOsteotomy
Theepiduralveinsrunapredictablecourse;identifying,coagulating,andcuttingthemcan
minimize blood loss during the procedure. The veins run through the epidural fat and
shouldbecoagulatedwhileseparatingthefatfromthedura.Asecondseriesofveinsrun
alongthemedialaspectofthepedicle,distallyalongthecourseoftheexitingnerveroot
and proximally over the pedicle and deep to the superior facet. When reaching around
ventrally, care should be made to avoid the segmental vessels running along the
midportion of the lateral vertebral body. As well, failure to separate the plane of the
mediastinum from the ventralbodycan lead to significant mediastinal venous bleeding
during dissection lateral to the vertebral body. It is imperative to stay along the lateral
aspectofthevertebrawhendissectinganteriorly.
OsteotomyClosure
Closureof theosteotomyis performedafterensuring adequateresectionof theposterior
wallofthevertebralbodyandaftercompleteresectionofthepedicleshasbeenperformed.
Ifdifficulty isencountered closingthe osteotomy,thesurgeon shouldconsiderresecting
moreboneanteriorlyfor adequatedecompression.Inadequateboneresectionisthe main
reasonosteotomiesdonotclose.
Tojudgethereductionoftheposteriorcolumn,theinferiorfacetofthelevelproximal
totheosteotomycanbepreservedandreducedtothe superiorfacet oftheleveldistalto
theosteotomy.Thiswillensurea stableposteriorcolumnwithstructuralbonecontinuity
andpreventovershorteningduringclosure.Closurecanbeachievedthroughtheuseofa
hook-based central rod (Fig. 3.7), through compression of the periapical anchors with
temporary short rods, or with three- or four-rod constructs using side-to-side rod
connectors.Ifposteriorcolumncontinuitycannotbeachievedthroughosteotomyclosure,
structuralbonegraft(fromadjacentribsorlargespinousprocesses)canbeusedtofillthe
posteriordefects.
Type4:TransdiskalVariant
ModifyingtheproximalresectionofthePSOtoextendacrossthediskspaceprovidesfor
a greaterresection and enables bone-on-bonecontact through the anteriorcolumn. This
variation isparticularly useful in casesof diskitis withkyphoticcollapse (Fig.3.8) and
posttraumatickyphosis.
17
PSOwithPreviousAnteriorImplants
Anterior implants at the level of the planned osteotomy present a challenge when
performing posterior-based procedures. The implants can be removed either through a
formalanterior approach orthrough ananterior reacharoundprocedure from aposterior
approach
18
(Fig.3.9).Posteriorlythetransverse processesareremoved,anddissectionis
performed along the lateral aspect of the pedicle. The anterior implants are identified.
Takingcaretopreservetheexitingnerveroot,ametalcuttingburcanbeusedtocutthe
anterior rod proximal anddistal to the anterior screw. Some of the lateral bodyis then
removedtoidentifytheneckofthescrew,whichisthencutwiththebur.Thesegmentof
theanteriorscrewwiththeattachedrodisremoved.Theosteotomyisthenperformedin
theusualfashionandtheremainingshaftofthescrewisremovedwiththevertebralbody
resection(Fig.3.10).
Fig.3.7a,bSchematicof (a) apediclesubtractionosteotomyclosedwith (b) a centralrod.Note the reductionofthe
inferiorfacetoftheproximalleveltothesuperiorfacetofthedistallevel,re-creatinganewfacetjointandcontinuityof
the posterior column. (FromLewis SJ, GoldsteinS,Bodrogi A, etal. Comparison of pediclesubtraction and Smith-
Petersen osteotomies in correcting thoracic kyphosis when closed with a central hook-rod construct. Spine
2014;39:1217–1224.Reprintedwithpermission.)
Fig.3.8a–hLongcassette(a)lateraland(b)sagittalT2-weightedMRIofa73-year-oldwomanwithknowntuberculosis
unresponsive to medical treatment. Note the destruction and kyphotic collapse of the T10-T11 disk space and (c)
adjacent vertebralbodies with an associated epidural abscess noted on (d) gadolinium-enhanced T1-weighted MRI.
Longcassette(e)posteroanteriorand(f)lateralviewsdemonstrateaT4toL2posteriorreconstruction.(g)Atransdiskal
pedicle subtraction osteotomy was performed by resecting the posterior elements and pediclesof T11, theproximal
vertebralbodyofT11,theT10-T11disk,andthedistalvertebralbodyandendplateofT10.(h)Anewvertebralbody
wascreatingby reducingtheproximalbodyofT10 tothedistalvertebralbody of T11.Notethe inferiorfacetofT10
wasreducedtothesuperiorfacetofT12tomaintaintheintegrityoftheposteriorcolumn.
Type5:VertebralColumnResection
Forlargemultiplanardeformities,resectionofacompletevertebralbodycanprovidethe
mobilityinthespinetoachievetheneededcorrection.
19
Severekyphoticdeformities,like
those seen following tuberculosis, often require more extensive resections involving
multiplevertebraetoachievetheneededcorrection.CommonindicationsforVCRinclude
severekyphoscoliosis,congenitaldeformities(Fig.3.11),andrigiddeformitiessecondary
toprevioussurgery.
20
Theprocedureis performedinasimilarfashion toaPSO.Although thePSOisoften
performedforprimarilysagittalplanedeformities,theVCRcanaccommodatemultiplanar
deformities.Thesedeformitiesoften havemajorrotationalandtranslationalcomponents,
causing significant challenges to the exposure, the dissection, and the decompression,
especiallyontheconcaveside(Fig.3.12a,b).Caremustbetakenwhendissectingaround
the vertebral body on the concavity, to ensure that the dissection does not enter the
mediastinum.Similarly,withthesevererotation,thespinalcordwillbeshiftedagainstthe
concavity (Fig. 3.12c,d), making it vulnerable to injury with removal of the concave
pedicle. Thesechallenges are not asdifficult whenperforminga PSO forsagittal plane
deformities.
Fig.3.9a–hLongcassette(a)posteroanteriorand(b)lateralview,sagittalT2MRI(c),andCTcoronal(d),sagittal(e),
and representative axials (f) of a 69-year-old woman with coronal and sagittal malalignment following a previous
anteriorT12toL5fusionandcircumferentialextensiontothesacrumandpelvis.Thoracickyphosis(T5-T12)measures
45degrees,lumbar lordosis (T12-S1) measures 7degrees,thepelvicincidencemeasures 51 degrees, the sacralslope
measures 5 degrees,and the sagittalvertical axis measures12 cm. (g,h)Thepatient underwent anoffsetL2 pedicle
subtraction osteotomy through a posterior approach and proximal extension to T4, as demonstrated in the standing
postoperativelong-casetteposteroanterior(g)andlateral(h)ragiographs.TheL2anteriorscrewwasremovedfromthe
sameposteriorapproach.
ThestepsforaVCRaresimilartothoseforaPSO:exposure,followedbyinsertionof
implants,removal ofthetransverse processes,removal ofthemedial ribsand ribheads,
exposureofthe ventralvertebralbody,posteriordecompression,removal oftheconcave
pedicle, temporary concave rod, convex removal of the pedicle, and release of the
proximalanddistaldisks.Thevertebralbodycan beremovedpiecemealoren bloc.For
piecemealremoval, ashellof ventralvertebralbody cortexcanbe leftbehindto protect
themediastinalstructuresandserveasabarrierfortheanteriorstrutgraftorcage.Foren-
bloc resection, circumferential release of the disks needs to be performed to permit
adequatereleaseandremoval.Releaseoftheconcavesideofthediskisthemostdifficult.
Oftentheadjacentmedialribsontheconcavityneedtoberemovedtoprovidesufficient
accessforthe release.Thetap forthepediclescrews canbeused asajoystickfrom the
convexity to facilitate the complete removal of the vertebral body. The use of proper
retractorstoprotectthemediastinalstructuresduringanteriorbodyresectionisparamount.
Fig.3.10a–e(a)Intraoperative view of the lateral and anteriordissection performedto identifythe previouslyplaced
anteriorinstrumentationthrough a posteriorexposure.Notethepreservationof the exitingnerveroot.Ametal-cutting
high-speeddrill is used to cuttheanteriorrod proximal and distaltothescrew. After removal ofsomeofthe lateral
vertebralbody,afurthercutismadealongtheneckofthescrew.(b)Thescrewheadwiththeattachedrodisremoved.
(c)The shaftofthescrewisextractedwhencompletingtheosteotomy.(d,e)Aschematicdemonstratestheremovalof
the anterior implant. (From Lewis SJ, David K, Singer S, et al. A technique of anterior screw removal through a
posteriorcostotransversectomyapproach for posterior-based osteotomies. Spine 2010;35:E471–E474.Reprintedwith
permission.)
Fig. 3.11a–g (a) Anteroposterior and (b) lateral long cassette radiographs of a 19-year-old man with congenital
kyphoscoliosis.(c,d)Three-dimensionalreconstructionsdemonstratesaT11hemivertebraattheapexofthedeformity.
Thepatientunderwent(e)posteriorresectionofT11andT12and(f,g)posteriorreconstructionfromT5toL4.Aportion
of theresected vertebra was used as an anterior strut between T10 and L1 tomaintain the integrity of theanterior
column. Closure of the osteotomy was performed with proximalto distalconvex rodplacement with the temporary
concaverod,withloosenedsetscrewsinplacetopreventtranslation.
Fig.3.12a–dAxial(a)CTand(b)MRIofanon-rotatedthoracicspinewithkyphosis.Notethepositionoftheribheads
andthecentralposition of the spinal cord. (c) ComparativeCTofapatientwith a severe scoliosis. Notethemarked
rotationofthevertebra,theconvexlateralvertebralbodyabuttingtheposterioraspectoftheconvexrib,theveryventral
position of theconcave rib, andthe posterior positionof the convexrib head. (d)Axial MRI showsthe spinal cord
shiftedagainsttheconcaverib.
WhenperformingVCRwithmarkedrotation,itiseasiesttoenterthecanalthroughthe
convexforamentostartthedecompression.Thecompleteposteriorelementsofthelevel
toberesectedshouldberemoved,alongwiththelaminaeoftheadjacentlevels.Thiswill
provide good visualization of the spinal cord upon osteotomy closure. The concave
pedicle is carefully removed and a temporary rod is then placed on the concavity. The
majority of the remaining dissection and vertebrectomy can be performed from the
convexitywithoutthetemporaryrodbeingintheway.
A structuralanterior support graft, eithera part of theresected vertebra ora cage, is
insertedanteriorlytoguidethereductionandpreventovershortening.Alaminarspreader
canbeusedtodistractventrallyfromtheconcavesidetofacilitatethegraft/cageinsertion.
ClosureoftheVCRshouldbedonewithaconvexrod.Thetemporaryconcaverodisleft
inplace,withthesetscrewsloosened,preventingtranslationwithouthinderingosteotomy
closure.Reductionisofteneasiestfromproximaltodistal.Single-anddual-rodreduction
techniqueshave beendescribed.Reducing aproximal anddistalconvex rodto acentral
connector has also been described. Being familiar with multiple techniques and the
equipmentavailablewillenablethesurgeontotailorthemethodtothegivensituation.
Type6:MultilevelVertebralColumnResection
Severekyphoticangular deformities,oftensecondaryto remoteinfections,areamenable
toposterior-basedvertebralresections.Asinglelevelisofteninsufficient.Multiplelevels
ofthe remnantsofthe deformedvertebrae areresected(Fig. 3.13). Followingresection,
ventral distraction aids in lengthening the anterior column for placement of an anterior
cage/strut.Posteriorshorteningthroughtherodwillcompletethecorrection.
OsteotomiesforFixedLordosis
The correctionof fixed hyperlordosis requiresa combination ofanteriorshortening and
posteriorlengthening.Thisismostreliablyaccomplishedthroughaformalanteriorrelease
followed by a posterior correction (Fig. 3.14). Similar to severe kyphosis, where the
vertebral column is displaced posteriorly, in fixed hyperlordosis the spine is displaced
ventrally. This ventral displacement favors an anterior approach, with the spine being
superficial to the anterior abdominal wall. In cases of thoracic hyperlordosis, severe
narrowingofthemediastinumoccurs,withbronchialcompressionoccurringinthe more
severe cases. Even in cases with respiratory issues, these patients paradoxically benefit
fromformalanterior approachestodecreasethelordosisandhelpincreasethe kyphosis,
thereby increasing the anteroposterior diameter of the mediastinum, relieving the
bronchialcompression.
Anterior shortening can be accomplished with multiple-leveldiskectomiesfor global
hyperlordosisorthroughresectionofdiskandboneformorefocaldeformities(Figs.3.15
and3.16).Aposterior-columnreleaseandinstrumentationisthenperformed.Contouring
theposteriorrodintheappropriatesagittalplanewillthenreducethelordoticdeformity.
Formal posterior distraction after the circumferential release may cause unwanted
distractionoftheentirespineinsteadofjusttheposteriorcolumn,makingthereductionto
anunder-contouredrodthepreferredmethod.
Fig.3.13a–e(a)Anteroposteriorand(b)lateralviewsofa59-year-oldman withseverekyphosissecondarytoremote
infection.(c)CTsagittalviewshowsfourvertebraeautofusedventrallywithaseverefocalkyphosis,andhyperlordosis
ofthedistallumbarandthoracicspines.(d,e)Longcassetteradiographsdemonstratingcorrectionfollowingmultilevel
vertebrectomy,placementofananteriorcage,andposteriorT6topelvisinstrumentation.
Fig. 3.14a–d Supine (a) anteroposterior and (b) lateral long cassette radiographs of a 17-year-old boy with severe
neuromuscularlordoscoliosiswithpreviousBaclofen pump insertion. (c,d) Following L1 to S1anterior diskectomies,
intraoperativetractionandaposteriorT2topelvisinstrumentationandfusionwasperformed.
Fig. 3.15a–f (a) Anteroposterior and (b) lateral long cassette radiographs of a 47-year-old woman with a remote
Harrington rod instrumentation andfusion for adolescentidiopathicscoliosis. She presentedwith distal degeneration
andsagittalmalalignment.(c,d)AnL3pediclesubtractionosteotomyandanteriorlumbarinterbodyfusionsatL4–5and
L5-S1wereperformed, resulting in fixed lumbar hyperlordosis.Because ofthepatient’ssevere unhappiness with her
sagittalalignment,ananteriorL2–3diskectomyandresectionoftheproximalportionoftheL3vertebralbodyfollowed
byaL2–3posterior columnreleasewereperformed.Theposterior fusionmassreleasewasgentlydistracted and held
open with mesh cages, while an appropriately contoured rod was inserted from distal to proximal to reduce the
osteotomy.(e,f)Thisresultedinamorebalancedsagittalplane.(FromLewisSJ,GrayR,DavidK,KopkaM,Magana
S.TechniqueofReverseSmithPetersen osteotomy (RSPO)inapatientwithfixedlumbarhyperlordosis and negative
sagittalimbalance.Spine2010;35:E721–E725.Reprintedwithpermission.)
Fig.3.16a–cLateralradiographsofthepatientinFig.3.15demonstrating(a)theL3pediclesubtractionosteotomyand
(b) the planned resection for the reverse Smith–Petersen osteotomy. (c) Close-up lateral view of the lumbar spine
followingclosureofthecombinedanterior/posteriorosteotomy.(FromLewisSJ,GrayR,DavidK,KopkaM,Magana
S.TechniqueofReverseSmithPetersen osteotomy (RSPO)inapatientwithfixedlumbarhyperlordosis and negative
sagittalimbalance.Spine2010;35:E721–E725.Reprintedwithpermission.)
ChapterSummary
The approach to severe spinal deformities has significantly changed with theimproved
techniques,imaging,andinstrumentationthatareavailable.Animprovedoutcomewillbe
achievedwithcarefulpreoperativeplanning,adeepunderstandingofthedeformities,and
the knowledge and ability to perform the various correction techniques. Creating an
environment with experienced andskilledsurgical and perioperative teams will help to
predict and manage the complexities associated with the successful treatment of these
challengingcases.
Pearls
Obtaining appropriate preoperative imaging studies can help to better understand the complexities of the
deformityandthepatient’sanatomy,andtoplanforpotentialdifficultiesintheprocedure.
Carefulpreoperativeclinicalandradiographicevaluationwillhelptoassess the flexibility of the deformity,to
determine the fixation options, and to decide on the location, number, and type of osteotomies required to
achievethedesiredcorrection.
Accurate intraoperative spinal cord monitoring, including motor evoked potentials, is essential to the safe
completionoftheseprocedures.Understandingthetimingandmagnitudeofneuromonitoringchangeswilldirect
keyintraoperativedecisions.
Althoughpediclescrewinstrumentationistheprimarymethodofcurvecontrol,alternativefixationmethodssuch
as fusion mass screws or laminar hooks are important backup strategies, especially in revision surgery or
dysplasticanatomy.
Pitfalls
The artery of Adamkiewicz has a variable anatomy from T8 to L1, most commonly on the left side. When
consideringosteotomiesaroundthethoracolumbarjunction,protectingandsavingthenerverootsmaypreserve
keysourcesofbloodflow.
Careful and controlled reduction of three-column osteotomies is essential to prevent cord translation and
subsequent injury. Complete visualization of the cord and harmonious collaboration with the surgical team,
electrophysiologicalmonitoringteam,andnursingstaffisessentialforspinalcordsafety.
References
FiveMust-ReadReferences
1. Dorward IG, Lenke LG. Osteotomies in the posterior-only treatment of complex adult spinal deformity: a
comparativereview.NeurosurgFocus2010;28:E4PubMed
2.DommisseGF.Thebloodsupplyofthespinalcord.Acriticalvascularzoneinspinalsurgery.JBoneJointSurgBr
1974;56:225–235PubMed
3.BollDT,Bulow H,BlackhamKA,AschoffAJ,SchmitzBL.MDCTangiographyofthespinalvasculature andthe
arteryofAdamkiewicz.AJRAmJRoentgenol2006;187:1054–1060PubMed
4.LewisSJ,ArunR,BodrogiA,etal.Theuseoffusionmassscrewsinrevisionspinaldeformitysurgery.EurSpineJ
2014;23(Suppl2):181–186PubMed
5. Lewis SJ, Goldstein S, Bodrogi A, et al. Comparison of pedicle subtraction and Smith-Petersen osteotomies in
correctingthoracickyphosiswhenclosedwithacentralhook-rodconstruct.Spine2014;39:1217–1224PubMed
6. Schwab F,Patel A, UngarB,Farcy J-P, Lafage V. Adultspinaldeformity-postoperative standing imbalance: how
muchcanyoutolerate?Anoverviewofkeyparametersinassessingalignmentandplanningcorrectivesurgery.Spine
2010;35:2224–2231PubMed
Соседние файлы в папке Библиотека им академика М.И. Перельмана