Principles of Spine Trauma Anundiagnosedorsuboptimallymanagedspineinjurycanresultinaneurologicdeficitand permanently impair a patient's function and quality of life, and in some cases may lead to death. Archeological records from over 45,000 years ago are noted to forewarn that paralysis is incurable and this remains true today, butthatdoesnotthatnothingcanbedoneforpatientswhosustainsevereneurologicdeficits.Patientswith spinal cord injury today regain mobility, improve their quality of life, and achieve prolonged survival. Fractures anddislocationsofthespineareseriousinjuriesthatmostcommonlyoccurinyoungpeople.Nearly43%of patientswithspinalcordinjuriessustainmultipleinjuries.itisestimatedthateachyear50peoplein1million sustainaspinalcordinjury.Withthedevelopmentofregionaltraumacentersandincreasedtrainingof paramedicsandemergencymedicaltechnicians,thechancesofsurvivalafterseriousspinalcordinjuryhave increased.Overall,85%ofpatientswithaspinalcordinjurywhosurvivethefirst24hoursarestillalive10 years later compared with 98% of patients of similar age and sex without spinal cord injury. TERMINOLOGYOFSPINAL CORDINJURY Neuraltissueinjuriesaredividedintotwobroadetiologybasedcategories:primaryinjuryrefersto physicaltissuedisruptioncausedbymechanicalforces,andsecondaryinjuryreferstoadditionalneuraltissue damage resulting from the biologic response initiated by the physical tissue disruption. The extent of structural damagetoneuraltissueisindicatedbyotherdescriptiveterms.Concussionreferstophysiologicdisruption withoutanatomicinjury.Contusionreferstophysicalneuraltissuedisruptionleadingtohemorrhageand swelling(themostcommontypeofspinalcordinjury),orlaceration,whichdescribeslossofstructural continuityoftheneuraltissue(rareinblunttrauma).Theclinicalresponsetoinjuryistypicallydescribedin temporal terms: acute refers to the first few hours after injury; subacute typically refers to several hours to days followinginjury,andchronicreferstointervalsofweekstomonthsaftertheinjury.Thefunctional consequencesofspinalcordinjuryareusuallydescribedbytermsthatrefertotheseverityandpatternof neurologicdysfunction.Completespinalcordinjury,incompleteinjury,ortransientspinalcorddysfunction describe different grades of severity of neurologic injury. EVALUATION OF SPINAL INJURY History Adetailedhistoryofthemechanismofinjuryisimportant,butfrequentlyisunobtainableat theinitial examination.Themostcommoncausesofseverespinaltraumaaremotorvehicleaccidents,falls,diving accidents,andgunshotwounds.Spinalinjuryshouldbesuspectedinanypatientwithaheadinjuryorsevere facial or scalp lacerations.In any patient with recent trauma, complaints of neck pain or spinal pain should be considered indicative of a spinal injury until proved otherwise. Other risk factors associated with spinal injury, includeaninabilitytoassessneckpainbecauseofasecondarydistractinginjury,abnormalneurological findings,ahistoryoftransientneurologicalsymptoms,physicalsignsofspinaltrauma(e.g.,ecchymosisand abrasions),unreliableexamination,significantheadorfacetrauma,oraninconsolablechild.Ifthecervical spineisnotalreadyrigidlyimmobilizedinapatientwithanyoftheseriskfactors,immobilizationshouldbe applied before the physical examination is continued. Stable and unstable injuries Spinal injuries carry a double threat: damage to the vertebral column and damage to the neural tissues. While the full extent of the damage may be apparent from the moment of injury, there is always the fear that movement may cause or aggravate the neural lesion; hence the importance of establishing whether the injury is stable or unstable and treating it as unstable until proven otherwise.A stable injury is one in which the vertebral components will not be displaced by normal movements; inastableinjury,iftheneuralelementsareundamagedthereislittle risk of them becoming damaged.Anunstableinjuryisoneinwhichthereisasignificantriskof displacementandconsequentdamageorfurtherdamagetothe neuraltissues.Inassessingspinalstability,threestructuralelements mustbeconsidered:theposteriorosseoligamentouscomplex(or posterior column) consisting of the pedicles, facet joints, posterior bony arch,interspinousandsupraspinousligaments;themiddlecolumn comprising the posterior half of the vertebral body, the posterior part of theintervertebraldiscandtheposteriorlongitudinalligament;andthe anterior column composed of the anterior half of the vertebral body, the anteriorpartoftheintervertebraldiscandtheanteriorlongitudinal ligament(Denis,1983)(Fig.1).Allfracturesinvolvingthemiddle column and at least one other column should be regarded as unstable. Mechanism of injury There are three basic mechanisms of injury: traction (avulsion), direct injury and indirect injury. Tractioninjury.Inthelumbarspineresistedmuscleeffortmayavulsetransverseprocesses;inthe cervical spine the seventh spinous process can be avulsed (clayshovellers fracture). Directinjury.Penetratinginjuriestothespine,particularlyfromfirearmsandknives,arebecoming increasingly common.Indirect injury. This is the most common cause of significant spinal damage; it occurs most typically in a fall from a height when the spinal column collapses in its vertical axis, or else during violent free movements of the neck or trunk. A variety of forces may be applied to the spine (often simultaneously): axial compression, flexion, lateral compression, flexion-rotation, shear, flexion-distraction and extension.Spinalinjuriesmaydamagebothboneandsofttissue(ligaments,facetjointcapsuleandintervertebral disc).The bone injury will usually heal; however, if the bone structures heal in an abnormal position the healed soft tissues may not always protect against progressive deformity. Early management The essential principle is that if there is the slightest possibility of a spinal injury in a trauma patient, the spine must be immobilized until the patient has been resuscitated and other life-threatening injuries have been identified and treated. Immobilization is abandoned only when spinal injury has been excluded by clinical and radiological assessment. Cervical spine.The head and neck are supported in the neutral position. A backboard, sandbags, a forehead tape and a semirigid collar are applied.Thoracolumbar spine. The patient should be moved without flexion or rotation of the thoracolumbar spine. A scoop stretcher and spinal board are very useful; however in the paralysed patient, there is a high risk of pressure sores adequate padding is essential. If the back is to be examined, or if the patient is to be placed onto a scoop stretcher or spinal board, the logrolling technique should be used. Fig.1.StructuralelementsofthespineThe verticallinesshowDenisclassificationofthe structural elements of the spine. Physical Examination Ageneralphysicalexaminationisdonewiththe patientsupine.Thepatientsmentalstatusandthelevelof consciousnessshouldbedeterminedquickly,including pupillary size and reaction. Epidural or subdural hematoma,adepressedskullfracture,orotherintracranial pathological conditions may cause progressive deterioration in neurologicalfunction.TheGlasgowComaScaleisusefulin determining the level of consciousness.Thepatientmaybesupportinghisorherheadwith their hands a warning to the examiner to be equally careful! Theheadandfacearethoroughlyinspectedforbruisesor grazes which could indicate indirect traumatothecervicalspine.Theneckisinspectedfor deformity, bruising or penetrating injury (Fig.2). The bones and soft tissues of the neck are gently palpated for tenderness and areas of bogginess, or increased space betweenthespinousprocesses,suggestinginstabilityduetoposteriorcolumnfailure.Thespinousprocesses should be palpated from the upper cervical to the lumbosacral region. A painful spinous process may indicate a spinalinjury.Palpabledefectsintheinterspinousligamentsmayindicatedisruptionofthesupporting ligamentouscomplex.Thebackoftheneckmustalsobeexaminedbutthroughouttheentireexaminationthe cervicalspinemustnotbemovedbecauseoftheriskofinjuringthecordinanunstableinjury.Thebackis inspectedfordeformity,penetratinginjury,haematomaorbruising.Theboneandsoft-tissuestructuresare palpated, again with particular reference to the interspinous spaces. A haematoma, a gap or a step are signs of instability. General Examination shock Three types of shock may be encountered in patients with spinal injury:Hypovolaemicshockissuggestedbytachycardia,peripheralshutdownand,inlaterstages,hypotension. Neurogenicshockreflectslossofthesympatheticpathwaysinthespinalcord;theperipheralvesselsdilate causinghypotensionbuttheheart,deprivedofitssympatheticinnervation,doesnotrespondbyincreasingits rate. The combination of paralysis, warm and well-perfused peripheral areas, bradycardia and hypotension with a low diastolic blood pressure suggests neurogenic shock. Spinalshockoccurswhenthespinalcordfailstemporarilyfollowinginjury.Evenpartsofthecordwithout structural damage maynot function. Below the level of the injury, the muscles are flaccid, the reflexes absent and sensation is lost. This rarely lasts for more than 48 hours and during this period it is difficult to tell whether the neurological lesion is complete or incomplete. A positive bulbocavernosus reflex or return of the anal wink reflexindicatestheendofspinalshock.IfnomotororsensoryfunctionbelowthelevelofinjurycanbeFig.2 a.Severefacialbruisingalways suspectahyperextensioninjuryof the neck. b.Bruisingoverthelowerback shouldraisethesuspicionofa lumbar vertebral fracture. documentedwhenspinalshockends,acompletespinalcordinjuryispresent,andtheprognosisispoorfor recovery of distal motor or sensory function. Neurological Evaluation A full neurological examination is carried out in every case; this may have to be repeated several times duringthefirstfewdays.Eachdermatome,myotomeandreflexistested.UseoftheAmericanSpinalInjury Association(ASIA)formishelpfulinorganizingthisevaluation.Adetailedinitialneurologicalexamination, including sensory, motor, and reflex function, is important in determining prognosis and treatment .Thepresence of an incomplete or complete spinal cord injury must be determined and documented by meticulous neurological examination.Sensory examination is performed with light touch, then pinpricks (using a sterile needle), beginning at the head and neck and progressing distally, to examine specific dermatome distributions (see Fig. 3). Motorexaminationshouldbesystematic, beginningwiththeupperextremities.During motor examination, it is important to differentiate betweencompleteandincompletespinalcord injuriesandpurenerverootlesions.Keymuscle groupsandtheircorrespondingnerverootlevels thatshouldbeevaluatedinapatientwithspinal cordinjury.Afterexaminationoftheextremities and trunk, the presence or absence of sacral motor sparingshouldbedeterminedbyvoluntaryrectal sphincterortoeflexorcontractions.Ifvoluntary contractionofthesacrallyinnervatedmusclesis presentwithsacralsensation,theprognosisfor recovery of motor function is good. The presenceofananalreflexwithoutsacralsensationis consistentwithacompleteinjury.Quadriplegiais indicated by flaccid paralysis of the extremities. Spinal Cord Syndromes Spinalcordsyndromesresultfromincompletetraumaticlesions.Bydefinition,anincompletespinal cord injury is one in which some motor or sensory function is spared distal to the cord injury. A complete spinal cord injury is manifested by total motor and sensory loss distal to the injury.When thebulbocavernosus reflex is positive, and no sacral sensation or motor function has returned, the paralysis is permanent and complete in most patients. AnincompletespinalcordsyndromemaybeaBrown-Squardsyndrome,centralcordsyndrome, anterior cord syndrome, posterior cord syndrome, or rarely monoparesis of the upper extremity. (see Fig. 5) Centralcordsyndromeisthemostcommon.Itconsistsofdestructionofthecentralareaofthespinal cord,includinggrayandwhitematter.Generally,patients haveaquadriparesisinvolvingtheupperextremitiestoa greaterdegreethanthelower.Sensorysparingvaries,but usually sacral pinprick sensation is preserved. Brown-Squard syndrome is an injury toeither half of the spinal cord.It is characterized by motor weakness on thesideofthelesionandthecontralaterallossofpainand temperaturesensation.Prognosisforrecoveryisgood,with significant neurological improvement often occurring.Anteriorcordsyndromeusuallyiscausedbya hyperflexioninjuryinwhichboneordiscfragments compresstheanteriorspinalarteryandcord.Itis characterizedbycompletemotorlossandlossofpainand temperaturediscriminationbelowthelevelofinjury.The posteriorcolumnsaresparedtovaryingdegrees(seeFig. 35-9D),resultinginpreservationofdeeptouch,position sense,andvibratorysensation.Prognosisforsignificant recovery in this injury is poor.Posteriorcordsyndromeinvolvesthedorsal columnsofthespinalcordandproduceslossof proprioceptionvibratingsense,whilepreservingother sensoryandmotorfunctions.Thissyndromeisrareand usually is caused by an extension injury.Conusmedullarissyndrome,orinjuryofthesacralcord(conus)andlumbarnerverootswithinthe spinalcanal,usuallyresultsinareflexicbladder,bowel,andlowerextremities.Mostoftheseinjuriesoccur between T11 and L2.Cauda equina syndrome, or injury between the conus and the lumbosacral nerve roots within the spinal canal, also results in arefl exic bladder, bowel, and lower limbs. Imaging X-rayexaminationofthespine ismandatoryforallaccidentvictims complaining of pain or stiffness in theneckorbackorperipheral paraesthesiae,allpatientswithhead injuriesorseverefacialinjuries (cervicalspine),patientswithrib fracturesorsevereseat-beltbruising (thoracicspine),andthosewithsevere pelvicorabdominalinjuries (thoracolumbarspine).Thisis performedduringthesecondarysurvey. Accidentvictimswhoareunconscious shouldhavespinex-raysaspartofthe routinework-up.(TRAUMASERIES: lateralviewofthecervicalspineand anteroposteriorviewsofthechestand pelvis.).Painisoftenpoorlylocalized; views should include several segments above and below the painful area.In addition to anteroposterior and lateral views, open-mouth views are needed for the upper two cervical vertebrae and oblique views may be needed for the cervical as well as the thoracolumbar region. Lateral flexion andextensionviewscanbemadetodeterminethestabilityofthecervicalspine,butthesearenotroutinely recommended in the initial examination.CT is ideal for showing structural damage to individualvertebraeanddisplacementofbone fragmentsintothevertebralcanal.Infact,screening CTisemployedroutinelyinmanycentres;the drawback is its high level of radiation exposure. MRIisthemethodofchoicefordisplaying theintervertebraldiscs,ligamentumflavumand neural structures, and is indicated for all patients with neurologicalsignsandthosewhoareconsideredfor surgery.CTmyelography,withtheintrathecal introductionofcontrastagent,providesinformation onthedimensionsofthespinalcanal,impingement byfracturefragmentsorintervertebraldisc,androot avulsion. This investigation has been largely replaced by MRI.Three-dimensionalreconstructionofCT imagesdefinescertaincomplexfracturepatterns. SpiralCTallowshighresolutionsagittal reconstructionandwhenavailable,isusefulfor displaying fractures of the odontoid process. Principles of treatment The objectives of treatment are: to preserve neurological function; to minimize a perceived threat of neurological compression; to stabilize the spine; to rehabilitate the patient. Theindicationsforurgentsurgicalstabilizationare:(a)anunstablefracturewithprogressive neurological deficit and (b) controversially an unstable fracture in a patient with multiple injuries. Patients with no neurological injury Stable injuries. If the spinal injury is stable, the patient is treated by supporting the spine in a position that will cause no further strain; a firm collar or lumbar brace will usually suffice, but the patient may need to rest in bed until pain and muscle spasm subside. A progressive neurological deficit mayoccasionallydevelop, which could be an indication for decompression and fusion. Unstableinjuries.Ifthespinalinjuryisunstable,itshouldbeheldsecureuntilthetissueshealandthespine becomes stable. Alternatively (particularly in the thoracolumbar spine) internal fixation can be carried out. Patients with a neurological injury Once spinal shock has recovered, the full extent of the neurological injury is assessed. Caring for patients with neurological injury requires the infrastructure of an experienced multidisciplinary team; If the spinal injury is stable (which is rare), the patient can be treated conservatively and rehabilitated as soon as possible. With the usual unstable injury, conservative treatment can be still be used; this is highly demanding and is best carried out in a special unit. After a few weeks the injury stabilizes spontaneously and the patient can be got out of bed for intensive rehabilitation. This approach is applicable to almost all injuries. Early operative stabili- zation is preferred by many; it facilitates nursing by inexperiencedcarers and reduces the risk ofspinal defor-mity. Fracture of the cervical spine C1(Atlas) ring fracture Suddensevereloadonthetopoftheheadmaycauseabursting forcewhichfracturestheringoftheatlas(Jeffersonsfracture)(Fig.7). There is no encroachment on the neural canal and, usually, no neurological damage. The fracture is seen on the open-mouth view (Fig.6) (if the lateral masses are spread away from the odontoid peg) and the lateral view. A CT scan is particularlyhelpfulindefiningthefracture.Ifitisundisplaced,the injuryisstableandthepatientwearsasemi-rigidcollarorhalo-vestuntil the fracture unites. If there is sideways spreading of the lateral masses, this injury is unstable and should be treated by a halo-vest for several weeks. If there is persisting instability on x-ray, a posterior C1/2 fixation and fusion isneeded.Ahyperextensioninjurycanfractureeithertheanterioror posteriorarchoftheatlas.Theseinjuriesareusuallyrelativelystableand are managed with a halo-vest or semi-rigid collar until union occurs. Fig.6Open-mouthview:notethe C1lateralmassesoverhangover the lateral edges of the C2(unstable lesion) C2 pars interarticularis fractures (Hangmans Fractures) Thetermhangmansfracture (bilateralfracturesofthepars interarticularis of C2) originally referred toneckinjuriesincurredduringthe hangingofcriminals(Fig.8).Themost commoncauseofhangmansfracture nowisamotorvehicleaccidentwith hyperextensionoftheheadontheneck.Incivilianinjuries,themechanismismorecomplex,withvarying degrees of extension, compression and flexion. This is one cause of death in motor vehicle accidents when the forehead strikes the dashboard. Neurological damage, however, is unusual because the fracture of the posterior arch tends to decompress the spinal cord. Nevertheless the fracture is potentially unstable. Levineclassifiedthesefracturesintothreetypes(Fig.8). TypeI fractures are minimally displaced Because ligamentous injury is minimal, these fractures are stable and usually heal with 12 weeks ofimmobilizationinarigidcervicalorthosis.TypeIIfractureshave morethan3mmofanteriortranslationandsignificantangulation. Treatmentconsistsofapplicationofhaloring.Immobilizationina halovestdoesnotachieveormaintainreduction,andhalotraction withslightextensionmaybenecessaryfor3to6weekstomaintain anatomical reduction. The patient can be mobilized in a halo vest for the rest of the 3-month period. TypeIIIinjuriescombineabipedicularfracturewithposteriorfacet injuries.Theyusuallyhavesevereangulationandtranslation.Type III injuries are the only type of hangmans fracture that commonly require surgical stabilization. These fractures frequentlyareassociatedwithneurologicaldeficits.Openreductionandinternalfixationusuallyarerequired because of inability to obtain or maintain reduction of the C2-3. After posterior cervical fusion at the C2-3 level, halo vest immobilization for 3 months is necessary. C2 Odontoid process fracture Odontoidfracturesareuncommon.Theyusuallyoccurasflexioninjuriesinyoungadultsafterhighvelocity accidentsorseverefalls.However,theyalsooccurinelderly,osteoporoticpeopleasaresultoflow-energy trauma in which the neck is forced into hyperextension, e.g. a fall onto the face or forehead. Odontoid fractures have been classified by Anderson and DAlonzo (1974) as follows(Fig.9): Type I An avulsion fracture of the tip of the odontoid process due to traction by the alar ligaments. The fracture is stable (above the transverse ligament) and unites without difficulty. Type II A fracture at the junction of the odontoid process and the body of the axis. This is the most common (and potentially the most dangerous) type.The fracture is unstable and prone to non-union. Type III A fracture through the body of the axis. The fracture is stable and almost always unites with immobilization.Clinical features.The history is usually that of a severe neck strain followed by pain and stiffness due to muscle spasm.Thediagnosisisconfirmedbyhighqualityx-rayexamination;itisimportanttoruleoutanassociated occipito-cervical injury which commands immediate attention. In some cases the clinical features are mild and continue to be overlooked for weeks on end.Neurological symptoms occur in a significant numberof cases. Imaging.Plain x-rays usually show the fracture, although the extent of the injury is not always. Tomography is helpful but MRI has the advantage that it may reveal rupture of the transverse ligament; this can cause instability in the absence of a fracture. Treatment TypeIfractures.Isolated fractures of the odontoid tip are uncommon.Theyneedno morethanimmobilizationina rigidcollaruntildiscomfort subsides.TypeIIfractures Theseareoftenunstableand pronetonon-union,especially ifdisplacedmorethan5 mm.Undisplaced fractures can be held by fitting a halo-vest or in elderly patients a rigid collar. Displaced fractures should be reduced by traction and can then be held by operative posterior C1/2 fusion; Anterior screw fixation(Fig.10)issuitableforTypeII fracturesthatrunfromanterior-superior to posterior-inferior, provided thefractureisnotcomminuted,that the transverse ligament is not ruptured, thatthefractureisfullyreducedand the bone solid enough to hold a screw. Iffulloperativefacilitiesarenot available,immobilizationcanbe appliedbyusingahalo-vestwith repeated x-ray monitoring to check for stability. Type III fractures If undisplaced, these aretreatedinahalo-vestfor812 weeks. If displaced, attempts should bemadeatreducingthefractureby halotraction,theneckisthen immobilizedinahalo-vestfor812 weeks. Lower cervical spine Fractures of the cervical spine from C3 to C7 tend to produce characteristic fracture patterns, depending on the mechanism of injury: flexion, axial compression, flexionrotation or hyperextension Posterior ligament injurySuddenflexionofthemid-cervicalspinecanresultindamagetotheposteriorligamentcomplex(the interspinous ligament, facet capsule and supraspinous ligament). The upper vertebra tilts forward on the one below, opening up the interspinous space posteriorly The patient complains of pain and there may be localized tendernessposteriorly.X-raymayrevealaslightlyincreasedgapbetweentheadjacentspines.Aflexionview would, of course, show the widened interspinous space more clearly, but flexion should not be permitted in the earlypost-injuryperiod.Thisiswhythediagnosisisoftenmadeonlysomeweeksaftertheinjury,whenthe patient goes on complaining of pain. The assessment of stability is essential in these cases. If the angulation of thevertebralbodywithitsneighborexceeds11degrees,ifthereisanteriortranslationofonevertebralbody upon the other of more than 3.5 mm or if the facets are fractured or displaced, then the injury is unstable and it shouldbetreatedasasubluxationordislocation(Fig.11).Ifitiscertainthattheinjuryisstable,asemi-rigid collar for 6 weeks is adequate;if the injury is unstable then posterior fixation and fusion is advisable. Wedge compression fracture A pure flexion injury results in a wedge compression fracture of the vertebral body (Fig. 12). The middle and posterior elements remain intact and the injury is stable. All that is needed is a comfortable collar for 612 weeks. A note of warning: The x-ray should be carefully examined to exclude damage to the middle column and posterior displacement of the vertebral body fragment, i.e. features of a burst fracture (see below) which is potentially dangerous. If there is the least doubt, an axial CT or MRI should be obtained. Burst and compression-flexion (teardrop) fractures Thesesevereinjuriesareduetoaxialcompressionofthecervicalspine, usually in diving or athletic accidents (Fig.13).Ifthevertebralbodyiscrushedinneutralpositionoftheneck theresultisaburstfracture.Withcombinedaxialcompressionand flexion,anantero-inferiorfragmentofthevertebralbodyisshearedoff, producing the eponymous tear-drop(Fig.14) on the lateral x-ray. In both typesoffracturethereisariskofposteriordisplacementofthevertebral bodyfragmentandspinalcordinjury.Plainx-raysshoweitheracrushed vertebralbody(burstfracture)oraflexiondeformitywithatriangular fragmentseparatedfromtheantero-inferioredgeofthefracturedvertebra (theinnocent-lookingteardrop).Thex-rayimagesshouldbecarefully examinedforevidenceofmiddlecolumndamageandposterior displacement(evenveryslightdisplacement)ofthemainbodyfragment. Traction must be applied immediately and CT or MRI should be performed to look forretro-pulsion of bone fragments into the spinal canal.TREATMENT Ifthereisnoneurologicaldeficit,thepatientcanbetreatedsurgicallyor by confinement to bed and traction for24weeks,followedbyafurtherperiodofimmobilizationinahalo-vestfor68weeks.(Thehalo-vestisunsuitableforinitialtreatment becauseitdoesnotprovideaxialtraction).Ifthereisanydeteriorationof neurologicalstatuswhilethefractureisbelievedtobeunstable,andthe MRI shows that there is a threat of cord compression, then urgent anterior decompressionisconsideredanteriorcorpectomy,bonegraftingand plate fixation(Fig.15), and sometimes also posterior stabilization(Fig.16). Fracture-dislocations Bilateralfacetjointdislocationsarecausedbysevereflexionor flexionrotationinjuries.Theinferiorarticularfacetsofonevertebraride forward over the superior facets of the vertebra below. One or both of the articularmassesmaybefracturedortheremaybeapuredislocation jumped facets. The posterior ligaments are ruptured and the spine is unstable; often there is cord damage.Thelateralx-rayshowsforwarddisplacementofavertebraontheonebelowofgreaterthanhalfthe vertebrasantero-posteriorwidth.Thedisplacementmustbereducedasamatterofurgency.Skulltractionis used, starting with 5 kg and increasing it step-wise by similar amounts up to about 30kg. The entire procedure shouldbedonewithoutanaesthesia(orundermildsedationonly)andneurologicalexaminationshouldbe repeated after each incremental step. If neurological symptoms or signs develop, or increase, further attempts at closed reduction should be stopped. When x-rays show that the dislocation has been reduced, traction is diminished to about 5 kg and then maintained for 6 weeks. During this time MRI can be performed to rule out the presence of an associated disc disruption. At the end of that period the patient should still wear a collar for another 6 weeks; however, it may be more convenient to immobilize the neck in a halo-vest for 12 weeks(Fig.17). Anotheralternativeisto carry out a posterior fusion as soon as reductionhasbeenachieved;the patientisthenallowedupina cervicalbracewhichiswornfor68 weeks.Posterioropenreductionand fusionisalsoindicatedifclosed reduction fails.(fig.16) Theneedforpre-reduction MRIisfortheabilitytodiagnosean extrudeddiscfragmentwhichmay furthercompromiseanyneurological lesionbutcanbedealtwithby anteriordecompression(fig.15).This isparticularlyapplicabletoelderly patientsinwhomimmediateclosed reduction may be hazardous and long periodsontheirbackscanleadto pressure sores. UnilateralfacetdislocationThisisaflexionrotationinjuryinwhichonly one apophyseal joint is dislocated. There may be an associated fracture of the facet. Onthelateralx-raythevertebralbodyappearstobepartiallydisplaced(lessthan one-halfofitswidth);ontheanteroposteriorx-raythealignmentofthespinous processes is distorted. Cord damage is unusual and the injury is stable. Management is the same as for bilateral dislocation.As a general rule, if closed reduction fails, open reduction and posterior fixation are advisable.Afterreduction,ifthepatientisneurologicallyintacttheneckis immobilized in a halo-vest for 68 weeks. Patients left with an unreduced unilateral facet dislocation may develop neck pain and nerve root symptoms longterm if poorly managed. Double injuries Withhigh-energytraumathecervicalspinemaybeinjuredatmorethanonelevel.Discoveryofthe most obvious lesion is no reason to drop ones guard. Avulsion injury of the spinous processFractureoftheC7spinousprocessmayoccurwithsevere voluntary contraction of the muscles at the back of the neck; it is known astheclay-shovellersfracture.(Fig.18)Theinjuryispainfulbut harmless.Notreatmentisrequired;assoonassymptomspermit,neck exercises are encouraged. Cervical disc herniationAcutepost-traumaticdischerniationmaycauseseverepain radiatingtooneorbothupperlimbs,andneurologicalsymptomsand signsrangingfrommildparaesthesiatoweakness,lossofareflexand blunted sensation.Rarelyapatientpresentswithfull-blownparesis.ThediagnosisisconfirmedbyMRIor CTmyelography. Sudden paresis will need immediate surgical decompression. With lesser symptoms and signs, onecanaffordtowaitafewdaysforimprovement;ifthisdoesnotoccur,thenanteriordiscectomyand interbody fusion will be needed.(Fig.15) Neurapraxia of the cervical cord Accidentscausingsudden,severeaxialloadingwiththeneckinhyperflexionorhyperextensionare occasionally followed by transient pain, paraesthesia and weakness in the arms or legs, all in the absence of any x-ray or MRI abnormality. Symptoms may last for as little as a few minutes or as long as two or three days. Theconditionhasbeencalledneurapraxiaofthecervicalcordandisascribedtopinchingofthecordbythe bony edges of the mobile spinal canal and/or local compression by infolding of the posterior longitudinal ligamentortheligamentumflavum.Congenitalnarrowingofthespinalcanalmaybeapredisposingfactor. Treatmentconsistsofreassurance(afterfullneurologicalinvestigation)andgradedexercisestoimprove strength in the neck muscles. Sprained neck (WHIPLASH INJURY) Soft-tissue sprains of the neck are so common after motor vehicle accidents that they now constitute a veritable epidemic. There is usually a history of a lowvelocity rear-end collision in which the occupants body is forced against the car seat while his or her head flips backwards and then recoils in flexion. This mechanismhasgeneratedtheimaginativetermwhiplashinjury.Womenareaffectedmoreoftenthanmen, perhaps because their neck muscles are more gracile.ClinicalfeaturesOftenthevictimisunawareofanyabnormalityimmediatelyafterthecollision.Painand stiffnessoftheneckusuallyappearwithinthenext1248hours,oroccasionallyonlyseveraldayslater.Pain sometimesradiatestotheshouldersorinterscapularareaandmaybeaccompaniedbyother,moreill-defined, symptomssuchasheadache,dizziness,blurringofvision,paraesthesiainthearms.Neckmusclesaretender and movement often restricted. X-ray examination may show straightening out of the normal cervical lordosis, a sign of muscle spasm;in other respects the appearances are usually normal TreatmentCollarsaremorelikelytohinderthanhelprecovery.Simplepain-relievingmeasures,including analgesic medication, may be needed during the first few weeks. Thoracolumbar injuries MostinjuriesofthethoracolumbarspineoccurinthetransitionalareaT11toL2betweenthe somewhatrigidupperandmiddlethoraciccolumnandtheflexiblelumbarspine.Theupperthree-quartersof the thoracic segments are also protected to some extent by the rib-cage and fractures in this region tend to be mechanicallystable.However,thespinalcanalinthatareaisrelativelynarrowsocorddamageisnot uncommonandwhenitdoesoccuritisusuallycomplete.ThespinalcordactuallyendsatL1andbelowthat level it is the lower nerve roots that are at risk. Pathogenesis Pathogenetic mechanisms fall into three main groups: low-energy insufficiency fractures arising from comparatively mild compressive stress in osteoporotic bone;minor fractures of the vertebral processes due to compressive, tensile or tortional strains;highenergy fractures or fracture-dislocations due to major injuries sustained in motor vehicle collisions, falls or diving from heights, sporting events, horse-riding and collapsed buildings. Examination Patients complaining of back pain following an injury or showing signs of bruising and tenderness over thespine,aswellasthosesufferingheadorneckinjuries,chestinjuries,pelvicfracturesormultipleinjuries elsewhere, should undergo a careful examination of the spine and a full neurological examination, including rectal examination to assess sphincter tone. Imaging X-rays The anteroposterior x-ray may show loss of height or splaying of the vertebral body with a crush fracture. Widening of the distance between the pedicles at one level, or an increased distance between two adjacent spinous processes, is associated with posterior column damage. The lateral view is examined for alignment, bone outline, structural integrity, disc space defects and soft-tissue shadow abnormalities.CT and MRI Rapid screening CT scans are now routine in many accident units. Not only are they more reliable thanx-raysinshowingboneinjuriesthroughoutthespine,andindispensableifaxialviewsarenecessary,but they also eliminate the delay, discomfort and anxiety so often associated with multiple attempts at getting the rightviewswithplainx-rays.InsomecasesMRIalsomaybeneededtoevaluateneurologicalorothersoft-tissue injuries. Treatment Treatment depends on: (a) the type of anatomical disruption; (b) whether the injury is stable or unstable; (c) whether there is neurological involvement or not; and (d) the presence or absence of concomitant injuries. MINOR INJURIES Fractures of the transverse processes The transverse processes can beavulsedwith sudden muscular activity.Isolated injuries need nomore than symptomatic treatment. More ominous than usual is a fracture of the transverse process of L5; this should alert one to the possibility of a vertical shear injury of the pelvis. Fracture of the pars interarticularis A stress fracture of the pars interarticularis should be suspected ifagymnast or athlete orweight-lifter complains of the sudden onset of back pain during the course of strenuous activity. The injury is often ascribed to a disc prolapse, whereas in fact it may be a stress fracture of the pars interarticularis (traumatic spondylolysis). This is best seen in the oblique x-rays.Bilateral fractures occasionally lead to spondylolisthesis. The fracture usually heals spontaneously, provided the patient is prepared to forego his (more often her) athletic passion for several months. MAJOR INJURIES Flexioncompression injury This is by far the most common vertebral fracture and is due to severe spinal flexion(Fig 19a), though in osteoporotic individuals fracture may occur with minimal trauma. The posterior ligaments usually remain intact, althoughifanteriorcollapseismarkedtheymaybedamagedbydistraction.Painmaybequiteseverebutthe fractureisusuallystable.Neurologicalinjuryisextremelyrare.Patientswithminimalwedgingandastable fracturepatternarekeptinbedforaweekortwountilpainsubsidesandarethenmobilized;nosupportis needed. Those with moderate wedging (loss of 2040 per cent of anterior vertebral height) and a stable injury can be allowed up after a week, wearing a thoracolumbar brace(Fig.19c) or a body cast applied with the back in extension. At 3 months, flexionextension x-rays are obtained with the patient out of the orthosis; if there is no instability, the brace is gradually discarded. If the deformity increases and neurological signs appear, or if the patient cannot tolerate the orthosis, surgical stabilization is indicated(Fig.19b). Iflossofanteriorvertebralheightisgreaterthan40percent,itislikelythattheposteriorligaments havebeendamagedbydistractionandwillbeunabletoresistfurthercollapseanddeformity.Ifthepatientis neurologicallyintact,surgicalcorrectionandinternalfixationisthepreferredtreatment.Ifnervelossis incompletethereisthepotentialforfurtherrecovery;anyincreaseinkyphoticdeformityorMRIsignsof impending cord neurological compression would be an indication for operative decompression and stabilization. If there is complete paraplegia with no improvement after 48 hours, conservative management is adequate; the patientcanberestedinbedfor56weeks,thengraduallymobilizedinabrace.Withseverebonyinjury, however, increasing kyphosis may occur and internal fixation should be considered. Axial compression or burst injury Severe axial compression may explode the vertebral body, causing failure of both the anterior and the middlecolumns.Theposteriorpartofthevertebralbodyisshatteredandfragmentsofboneanddiscmaybe displacedintothespinalcanal.Theinjuryisusuallyunstable.Posteriordisplacementofboneintothespinal canal (retropulsion) is difficult to see on the plain lateral radiograph; a CT is essential. If there is minimal anterior wedging and the fracture is stable with no neurological damage, the patient is kept in bed until the acute symptoms settle and is then mobilized in a thoracolumbar brace or body cast which is worn for about 12 weeks.However, any new symptoms such as tingling, weakness or alteration of bladder or bowel function must be reported immediatelyand should call for further imaging by MRI; anterior decompression and stabilization may then be needed if there are signs of present or impending neurological compromise Fracture-dislocation Segmentaldisplacementmay occurwithvariouscombinationsof flexion,compression,rotationand shear.All three columns are disrupted andthespineisgrosslyunstable. These are the most dangerous injuries andareoftenassociatedwith neurologicaldamagetothe lowermostpartofthecordorthe caudaequina.Theinjurymost commonlyoccursatthe thoracolumbarjunction.X-raysmay showfracturesthroughthevertebral body,pedicles,articularprocesses andlaminae(Fig.20);theremaybe varyingdegreesofsubluxationor even bilateral facet dislocation. CT is helpfulindemonstratingthedegree ofspinalcanalocclusion.In neurologicallyintactpatients,most fracture-dislocationswillbenefitfromearlysurgery.Infracture-dislocationwithparaplegia,thereisno convincingevidencethatsurgerywillfacilitatenursing,shortenthehospitalstay,helpthepatients rehabilitationorreducethechanceofpainfuldeformity.Infracture-dislocationwithapartialneurological deficit,thereisalsonoevidencethatsurgicalstabilizationanddecompressionprovidesabetterneurological outcome than conservative treatment. In fracture-dislocation without neurological surgical stabilization will prevent future neurological complications and allow earlier rehabilitation. Cord transection Motor paralysis, sensory loss and visceral paralysis occur below the level of the cord lesion; as with cord concussion,themotorparalysisisatfirstflaccid.Thisisatemporaryconditionknownascordshock,butthe injuryisanatomicalandirreparable.Afteratimethecordbelowtheleveloftransactionrecoversfromthe shockandactsasanindependentstructure;thatis,itmanifestsreflexactivity.Within48hourstheprimitive anal wink and bulbocavernosus reflexes return. Within 4 weeks of injury tendon reflexes return and the flaccid paralysisbecomesspastic,withincreasedtone,increasedtendonreflexesandclonus;flexorspasmsandcontractures may develop with inadequate management. Spinal Deformities Introduction A thorough understanding of spinal anatomy is crucial for a comprehensive evaluation of a patient with spinaldisorders.Theprimaryrolesofthespinearemaintainingstability,protectingtheneuralelements,and allowing range of motion. Specifically adapted anatomic features facilitate these functions. The vertebra is the structuralbuildingblockofthespine,withspecificmorphologicandfunctionalrolesbasedonthevertebras positioninthespinalcolumn.Theintervertebraldisks,ligaments,andmusclesaddstabilityandcontrol.The spinal cord travels within, and is protected by, the spine. Paired nerve roots exit at each spinal level. Anatomy and Biomechanics Theaxialskeletoniscomposedof33vertebrae,including 7vertebraeintheneck,12vertebraeinthethoracicregion,5 vertebraeinthelumbarregion,5fusedvertebraeinthesacrum, andthecoccyxthattypicallyincludes4vertebralbodies, sometimespartiallyortotallyfusedtogether(Fig.21). Intervertebral discs separate the vertebrae except between the first andsecondcervicalvertebrae(C1andC2,respectively)and between the sacrumandthecoccyx.Thebodyofavertebraisshapedlikea short cylinder and is composed primarily of cancellous,well-vascularizedbonecoveredbyathinlayerof corticalbone.Withincreasingweight-bearingloads,thevertebral bodybecomesprogressivelytallerandwiderfromabove downward. The posterior arch includes right and left pedicles that projectposteriorlyfromtheposterolateralsurfaceofthevertebral body,andrightandleftlaminaethatprojectposteromediallyto fuse with the spinous process (Fig.22). The arch and body enclose andprotectthespinalcordandcaudaequinaandformthe vertebralforamen,throughwhichthenerverootspass.The spinousprocessprojectingposteriorlyandthetwotransverse processesthatextendlaterallyfromthepedicle-laminajunction provideoutriggerinsertionsitesforthemultiplemusclesand ligamentsthatmoveandstabilizethetrunk.Thefacetjointsprovidemotionbetweentwovertebrae.The superiorarticularprocessandfacetjointextendfromthepedicleofthevertebrabelow(caudal)toarticulate with the inferior articular process and facet joint that extends from the lamina of the vertebra above.

The vertebral canal extends from the foramen magnum to the sacrumand encloses the spinalcord and itsnerveroots.Theduramaterisseparatedfromthebonesbyanepiduralspacethatcontainsfatandan extensiveplexusofepiduralveins.TheduralsaccontinuesinferiorlytoapproximatelythemiddleoftheS2 vertebra. Inferior to the conus, the dural sac contains the cauda equina (lumbosacral nerve roots) and the filum terminale, a cord of tissue that travels inferiorly from the conus to merge with the periosteum on the dorsum of the coccyx . The first and second cervical vertebrae are different from the lower five cervical vertebrae (Fig 23). The atlas (C1 vertebra) lacks a spinous process and is essentiallyan oval ring of bone. The lateral portions of the C1 ring are thickened into a lateral mass that articulates with the occipital condyle superiorly and with the lateral mass of C2 inferiorly. The axis (C2 vertebra) has a toothlike protuberance, the dens, that projects upward from the body to provide structural support for the atlas. The dens provides a pivot point on which the head and atlas can rotate relatively freely on the relatively flat C1-C2 articular facets. Thecervicalspineisamobileplatformfortheskullandisthemostflexibleportionofthevertebral column. Motion of the cervical spine includes flexion and extension, right and left lateral bending, and right and leftrotation.Inyoungadults,normalneckmotionis70flexion,70extension,50lateralbending,and90 rotation to each side. The degree of motion between two vertebrae is determined primarily by the orientation of the facets; therefore, different vertebral segments contribute differing amounts to each plane of motion. The total arc of flexionextension, however, is greater in the lower cervical vertebral segments, with peak motion occurring at the C5-C6 level. Motion of the spine is often coupled. For example, lateral bending of the neck is accompaniedbyrotation,androtationofthecervicalspineiscoupledwithlateralbendingandflexion-extension. Thoracic vertebrae have costal facets at the upper and lower edges of the junction of the body with the archoneachside.Primarymotioninthethoracicspineislateralbendingandrotation,withlateralbending being greater in the lower thoracic segments and rotation being greater in the upper thoracic spine.Because of the increased axial loads and the lack of surrounding rib support, the horizontal diameter of a lumbar vertebraisgreaterthanitsheight.Lumbarvertebraearelargerandthickeranteriorly.Thesuperiorarticular facet of a lumbar vertebra faces mostly medially, and the inferior facet is directed laterally. Flexion-extension is the primary arc of motion in the lumbar spine, with greater movement occurring in the lower lumbar segments. The vertebral bodies of the lumbar spine support an average of 80% of the axial load experienced by the spinal column; the facet joints support the other 20%. Intervertebral Discs Theintervertebraldiscs contributeapproximately20% ofthelengthofthecervical andthoracicspineand approximately33%ofthe length of the lumbar region.In thecervicalandlumbar regions,thediscsarethicker anteriorlyThoracicdiscshave uniformheight.The intervertebraldiscincludesthe annulusfibrosusandthe nucleuspulposus(Fig.23).Thecentralnucleuspulposusiscomposedofwater,typeIIcollagen,and proteoglycanaggregates.Thiscompositestructureprovidesgoodresistancetorepeatedloadinginboth compression and tension. The load at the L3-L4 disc ranges from 30 kg while the individual is lying supine to more than 300 kg when the person is lifting a 20-kg weight with the spine flexed and the knees straight. Curves of the spine The vertebral column has four distinct curvescervical lordosis, lumbar lordosis, thoracic kyphosis, and sacralkyphosis(Fig.21).Instance,thesagittalverticalaxispassesthroughtheodontoid,posteriortothe cervical verte-brae,through the C7-T1 intervertebral disk, anterior to the thoracic vertebrae, through the T12-L1interver-tebral disk, posterior to the lumbar vertebrae, through the L5-S1 intervertebral disk, and anterior to the sacrum. Theprimarycurvesarethoseofthekyphoticthoracicandsacralregions.Theseformduringthefetal period.The secondary curves are those of the lordotic cervical and lumbar regions. These are initiated during the late fetal period but do not become significant until after birth when the spinal column begins to bear the weight ofthebodyandhead.Primarycurvesarecausedbythewedge-shapednatureofinvolvedvertebrae,whereas secondary curves are caused by differences in the anterior and posterior dimensions of the intervertebral disks. Thecervicallordoticcurvenormallyrangesfrom25to50degreeswithanapexatC4.Thethoracic spine anatomically refers to the named vertebral levels from T1 to T12. This region is usually kyphotic, with its apex around T7. The caudal aspect of the kyphosis typically decreases in sagittal angulation until the relatively neutralthoracolumbarjunction,whichhasarelativelystraightinflectionpoint.Normalthoracickyphosis usually ranges from 20 to 50 degrees in adults. The normal lumbar lordosis is between 40 and 70 degrees withanapexlocatedattheL3-4interspace.The lumbosacraljunctionisaninflectionpointforthe lordoticsegmentofthelumbarspinetothe kyphoticsacrum.Localkyphosisismeasuredby theanglecreatedbetweenalinealongtheinferior aspect of L5 and a line along the superior border of S1.Oneofthemostcriticalrelationshipsinthe humanspinethatsetsparametersforsagittal balanceisthelumbosacralpelvis.Recentstudies report that sagittal plane balance is mediated by the followingindependentfactors:sacralslope,pelvic tilt, pelvic incidence, and lumbar lordosis (Fig. 24). Sacral slope is the angle between the superior border of S1 and a line parallel to the horizon. The pelvic tilt is the angle between a line perpendicular tothehorizonandalinejoiningthemiddleofthe superiorsacralendplate.Pelvicincidence(PI),or pelvisacral angle, is defined as the angle between a line perpendicular to the sacral plate at its midpoint andalineconnectingthesamepointtothecenter ofthebicoxofemoralaxis.Thisnumberisfixed and some believe it is the angle on which all other spinal curves are based. SCOLIOSIS Scoliosisisanapparentlateral (sideways)curvatureofthespine.Apparent because, although lateral curvature does occur, thecommonestformofscoliosisisactuallya triplanar deformity with lateral, anteroposterior and rotational components. Two broad types of deformity are defined: postural and structural.Postural Scoliosis Inposturalscoliosisthedeformityis secondaryorcompensatorytosomecondition outsidethespine,suchasashortleg,orpelvic tiltduetocontractureofthehip.Whenthe patientsits(therebycancellingleglength asymmetry) the curve disappears. Local muscle spasmassociatedwithaprolapsedlumbardiscmaycauseaskewback;althoughsometimescalledsciatic scoliosis this, too, is a spurious deformity.(Fig.31) Structural scoliosis Instructuralscoliosisthereisanon-correctabledeformityoftheaffectedspinalsegment,anessential componentofwhichisvertebralrotation.Thespinousprocessesswingroundtowardstheconcavityofthe curveandthetransverseprocessesontheconvexityrotateposteriorly.Primarycurvespresentscharacteristic modifications:cuneiformvertebraeatthecenterofcurvature,whileoutheredgevertebraesarerhomboidand reseamblestonormalaspect(neutralvertebrae).Inthethoracicregiontheribsontheconvexsidestandout prominently, producing the rib hump, which is a characteristic part of the overall deformity(gibbus) determining thecharacteristicovalar-obliquethoraciccage.Secondary(compensatory)curvesnearlyalwaysdevelopto counterbalance the primary deformity; they are usually less marked and more easily correctable, but with time they, too, become fixed. Oncefullyestablished,thedeformityisliabletoincreasethroughoutthegrowthperiod.Thereafter, further deterioration is slight, though curves greater than 50 degrees may go on increasing by 1 degree per year. With very severe curves, chest deformity is marked and cardiopulmonary function is usually affected. Classification Aetiology Most cases have no obvious cause (idiopathic scoliosis). This group constitutes about 80 per cent of all casesofscoliosis.Thedeformityisoftenfamilialandthepopulationincidenceofseriouscurves(over30 degrees and therefore needing treatment) is three per 1000; trivial curves are very much more common. Othervarietiesarecongenitalorosteopathic(duetobonyanomalies)(fig.32),neuropathic,myopathic (associated with some muscle dystrophies poliomyelitis, syringomyelia, Friedreich heredoataxia), scoliosis in neurofibromatosis Recklinghausen, posttraumatic scoliosis, skeletal genetic disorders (Morquio disease, Marfan disease, osteogenesis imperfecta), scoliosis in vertebral tumors . Primary curvature Thoracic scoliosis (Th6-Th12) ussualy with right side convexity and lombar compensatory curvature. Progression is more severe with early-onset Thoraco-lumbar scoliosis(Th11-L3) - right side convexity, sever prognosis Lumbar scoliosis(Th6-L2) left side convexity, with better outcome than the first two Cervico-Thoracicscoliosisleftsideconvexitywiththoracicandthoraco-lumbarcompensatory curvature. Develops ussualy in individuals with poliomyelitis and neurofibromatosis Double primary curve scoliosis(Th6-Th11 and Th11-L4) one thoracic dextroconvex curvature and a lumbar one with left side convexity, balanced, fearly good prognosis. Degree of curvature I.