Surgical Technique

Guide

Cervical Interbody System

BENGAL

i n t r o d u c t i o n

The fusion technique used in anterior cervical interbody fusion has gone through many

transformations, from the use of a tricortical iliac crest graft as advocated by Smith

and Robinson1, to Cloward’s bicortical dowel-shaped graft2. The BENGAL® Cervical

Interbody System represents further advancement by adopting the benefits of a

mechanical device while facilitating conditions for fusion, which can be visualized

due to the radiolucent property of the biocompatible cage material.

The BENGAL Cage is a carbon fiber reinforced polymer (CFRP) interbody fusion and

VBR device. The cage distracts and maintains the intervertebral height, as well as

providing restoration of cervical lordosis. The range of cages available is based on

natural anatomical variation.

INTRoduCTIoN i

SuRGICAL TEChNIquE 2

Pos i t ioning the Pat ient 2

Step 1: Exposure 2

Step 2: Making the Inc is ion 2

Step 3: Removal of the disc and

Preparat ion of the Endplates 4

Step 4: Choosing the Appropr iate BENGAL Cage 6

Step 5: harvest ing, Preparat ion and Insert ion

of Graft into BENGAL Cage 7

Step 6: Insert ion of the BENGAL Cage 7

Step 7: Closure of the Wound 8

Step 8: Post-operat ive Care 8

c o n t e n t s

Consulting Surgeon

John W. Brantigan, M.D.

South Texas orthopaedic &

Spinal Surgery Associates

huebner Medical Center

9150 huebner, Suite 350

San Antonio, Texas uSA

2

surgical technique

Positioning the Patient

The patient is given general endotracheal anesthesia, then placed in the supine position with the neck

extended. It is helpful to place rolled blankets under the scapulae and a rolled towel under the neck to

provide extension of the cervical spine. Both arms are placed at the patient’s side so that X-rays can be

taken with traction applied to the arms by an unscrubbed assistant at the foot of the table.

Step 1: expoSure

• Theexposurecanbemadeeitherontheleftorrightsideaccordingtosurgeonpreference.Althoughriskofretractioninjurytotherecurrentlaryngealnerveishigherfromtheright,aleft-sidedapproachhasthepossibilityofinjuringthethoracicductandismorelikelytoinjuretheesophagus.Mostright-handedsurgeonsprefertoapproachfromtherightside.Atransverse“hemi-collar”incisionismadeparalleltotheclavicleextendingfromthesternocleidomastoidmuscletothemidline(Figure1).

FIGURE2a

Step 2: making the inciSion

• Thecrico-thyroidmembraneisattheC5-6disclevel.Theincisionisusuallytwoorthreefingerbreadthsabovetheclavicle,dependingonvertebralleveldesired.Theincisionistakenthroughthesubcutaneousfattothesurfaceoftheplatysma.Althoughsomesurgeonsdividetheplatysmainlinewiththeskinincision,itismorecosmetictoelevatetheskinadistanceoftwotothreecentimetersoneithersideoftheskinincisionanddividetheplatysmainthedirectionofitsfibers(Figure2a).

FIGURE1

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• Thesurgeoncanuseeithera“peanutsponge”orindexfingertoopentheplaneofcleavagebetweenthecarotidsheathlaterallyandthetracheaandesophagusinthemidline(Figure2d),exposingtheanteriorcervicalspine.

• Thelayerofdeepcervicalfasciaisincisedalongtheanteriorborderofthesternocleidomastoidmuscle(Figure2b).

FIGURE2b

FIGURE2c

FIGURE2d:Cross-sectionalviewoftheneckdemonstratestheplaneof

cleavagebetweenthecarotidsheathlaterallyandthetrachea

andesophagusmedially.

NOTE: Thediagonalfibersofthemuscle.

• Bluntdissectionisusedtodeveloptheintervalbetweenthecarotidsheathandthemidlinestructures,stayingclosetothetrachea.ThefasciaalongthelateraledgeofthesuperiorbellyoftheomohyoidmuscleiscutwithaMetzenbaum(straightbluntscissors)untiltheedgeoftheesophagusisvisible(Figure2c).

Tracheal Cartilage

Vertebral Artery

Longus Coil

Muscle

Common Carotid Artery

Vagus Nerve

C-6

Thyroid Gland

Internal Jugular

VeinStemocleidomastoid

Recurrent Laryngeal

Nerves

Sympathetic Trunk

oesophagus

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surgical technique

FIGURE2e

• UseofaCasparorsimilarvertebraldistractorisrecommendedtodistractacrossthediscspace.Longshankdistractionscrewsareinsertedinthevertebraaboveandbelowtheaffecteddisc,makingsurethatthescrewshanksareparallel.Thedistractorisapplied,stretchingthediscspace(Figure3a).

• Anteriorosteophytesoverlyingthediscspacemayneedtoberemovedusingarongeurorosteotome.Attimes,theseosteophytesaddsubstantiallytotheanterior-posteriordimensionofthevertebralbody.Theanteriorannulusisincisedandremoved.Thenucleusisremovedwithapituitaryrongeurorcurette.Thecartilaginousendplateispeeledfromthevertebralbodiesaboveandbelowusingasmallperiostealelevatororcurette.Dissectionshouldnotbeundertakenlateraltotheupslopeoftheuncovertebraljointoneithersidetoassureprotectionofthevertebralarteries.Afterthedischasbeenremoved,greaterdistractioncanusuallybeachievedusingthedistractor.

Step 3: removal of the diSc and preparation of the endplateS

• Cauteryisusedinthemidlineoverthecervicalspine,followedbya“peanutsponge”toreflectthefasciaandlonguscolimuscles(Figure2e).

• Ifdesired,self-retainingretractorsmaybeplaced.Theblunt-toothbladesareplacedmedial-lateral,takingcarethattheteethremainwithinthelonguscolimusclefibers.Thesmoothbladesareplacedsuperior-inferior.

• A22-gaugespinalneedleisplacedintheappropriatediscandalateralX-raytakentoverifyanatomiclevel.Iftheneedlehasbeenpre-benttoa90°angle1cmfromitstip,excessivepenetrationwillbeprevented.

FIGURE3a

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b e n g a l S u r g i C a l t e C h n i q u e

• Whilesomesurgeonshaverecommendedthatposteriorosteophytesnotberemovedduetoincreasedriskofdamagetothespinalcord3,4,5,Cloward2,6andothershaverecommendedthatallposteriorosteophytesberemoved.Atinyup-angledcuretteorKerrisonrongeurcanbeusedtoremovetheposteriorosteophytes,ifnecessary.Thisdissectioncanbecarriedlaterallyuntiltheneuralforamencanbeenteredwithanervehooktoverifythatthenerverootisfreeandthatallnuclearmaterialhasbeenremoved(Figure3b).Vigorousprobingintotheforamenshouldbeavoidedtopreventpenetrationofthevertebralartery.

• Thecage’sspecificrasps(Figure4a)areusedtoflattentheendplateandensurethatallendplatecartilagehasbeenremoved.AsrecommendedbyRobinson7,subchondralboneshouldbepreservedasfaraspossiblesothatitcanfunctionasabearingsurfacefortheimplant.

FIGURE3b

NOTE: Theosteophyteshavebeenremovedonthepatient’sleftsideandanervehookverifiesthattheforamenisfree.Ontherightside,theosteophytehasnotbeenremovedandtheaccesstothespinalcanalislimited.

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surgical technique

FIGURE4a

Step 4: chooSing the appropriate Bengal cage

• ThetrialsfortheBENGALCage(Figure4a)areusedtogaugetheselectionofimplantsize.

• Figure4bshowstheuseofatrialforgaugingboththeheightandthesizeoftheimplantrequired,andtoassurethateachsurfaceisflatandthespaceisequallytaperedfromfronttoback.Eachtrialisslightlysmallerthantheactualcageimplant(0.75mm)toallowtheimplantasnugfit.

RASPS TRIALS

FIGURE4b

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Step 5: harveSting, preparation and inSertion of graft into Bengal cage

• TheBENGALCagemaybefilledwithautologouscancellousbone.

• Theselectedcageisengagedwiththethreadedportionofthecageinserter(Figure5)andplacedinthefillerblock.Usingthecagefillerblock,thecancellousboneispackedfirmlyintothehollowareaofthecage.

Step 6: inSertion of the Bengal cage

• Thecageisthengentlytappedintotheprepareddiscspace(Figure6)usingtheinserterdesignedtopreventdrivingthecagetoofarposteriorly.Undernormalcircumstances,thecageshouldberecessed1to2mmfromtheanteriorcortex.AfinalX-rayistakentoverifypositionoftheimplant.

FIGURE5

FIGURE6

8

surgical technique

Step 7: cloSure of the wound

• Absolutehemostasismustbeachievedpriortoclosure.Thevertebralbodydistractorisremovedalongwiththelongshankdistractionscrews(Figure7).Bonewaxisplacedinthescrewholes.Theanesthetistisaskedtomovethecervicalspinethrougharangeofflexionandextensionpositions,toensurethatstabilityhasbeenachieved.Ananteriorcervicalstabilizationdevice,suchastheSKYLINE®AnteriorCervicalPlate,canbeappliediflessthanoptimumstabilityisobserved.Asmalldrainisplaceddeepinthewound.Theself-retainingretractorsareremovedandthetissuelayersclosed.Theplatysmaisusuallytheonlylayerrequiringsuture.Subcutaneousorsubcuticularsuturesareplacedandsteri-stripsappliedtotheskin.Asoftcervicalcollarmaybeapplied.

Step 8: poSt-operative care

• Thepatientisusuallyplacedinthesurgicalintensivecareunitovernighttoobservefortheunlikelybutdangerouspossibilityofairwayobstruction.Thepatientisallowedtoambulate24hourspost-operatively.Thedrainisremovedandthepatientdischargedwhencomfortable,usuallyonthesecondorthirdpost-operativeday.Thepatientisinstructedtominimizemotionofthecervicalspineandwearthesoftcollarforonemonthpost-operatively.

FIGURE7

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indications:

the BEnGaL® cervical interbody system is indicated for use as an intervertebral body fusion device in skeletally mature patients with degenerative disc disease (defined as discogenic back pain with degeneration of the disc confirmed by patient history and radiographic studies) at one level of the cervical spine with accompanying radicular symptoms. Patients should have six weeks of non-operative treatment prior to surgery. BENGAL implants are used to facilitate fusion in the cervical spine (C2-T1) and are placed via an anterior approach using autogenous bone. When used as an interbody fusion device, DePuy Spine supplemental fixation may be used.

the BEnGaL cervical interbody system is indicated for use in the thoracolumbar spine (i.e., T1-L5) to replace a diseased vertebral body resected or excised for the treatment of tumors, to achieve anterior decompression of the spinal cord and neural tissues, and to restore the height of a collapsed vertebral body. This system is also indicated for treating fractures of the thoracic and lumbar spine. This system is designed to restore the biomechanical integrity of the anterior, middle and posterior spinal column even in the absence of fusion for a prolonged period. When used as a vertebral body replacement device this system is intended for use with DePuy Spine supplemental internal fixation.

Limited Warranty and disclaimer: dePuy spine products are sold with a limited warranty to the original purchaser against defects in workmanship and materials. any other express or implied warranties, including warranties of merchantability or fitness, are hereby disclaimed.

WaRninG: in the Usa, this product has labeling limitations. see package insert for complete information.

caUtion: Usa Law restricts these devices to sale by or on the order of a physician.

to order in the Us, call dePuy spine customer service (1-800-227-6633).

Not all products are currently available in all markets.

reFerenCeS

1. Robinson, RA, Smith, GW: The treatment of certain cervical spine disorders by anterior removal of the intervertebral disc and interbody fusion. JBJS 40: 607, (1958).

2. Cloward, RB: Vertebral body fusion for ruptured cervical discs. description of instruments and operative technique. Amer J Surg 98: 722-727, (1959).

3. Bohlman, hh: Cervical spondylosis with moderate to severe myelopathy. A report on seventeen cases treated by Robinson anterior cervical discectomy and fusion. Spine 2: 151-162, (1977).

4. Gore, dR, Sepic, SB: Anterior cervical fusion for degenerated or protruded discs. A review of one hundred forty-six patients. Spine 9: 667-671, (1984).

5. Stauffer, ES, Kraus, dR: Spinal cord injury as a complication of anterior cervical fusion. Clinical orthopoedics 112: 130, (1975).

6. Cloward, RB: The anterior surgical approach to the cervical spine. The Cloward procedure: past, present and future. Spine 13: 823, (1988).

7. Robinson, RA, Walker, AE, Ferlic, dC, Wiecking, dK: The results of anterior interbody fusion of the cervical spine. Journal 44A: 1569-1587, (1962).

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CR21-20-000 1/11 AddB/uM

Cervical Interbody System

BENGAL