4Blood supplyTwo posterior spinal arteriesAnterior spinal artery – formed by the confluence of two vertebral arteriesThe lower cervical cord is a region of relative ischemia and is vulnerable for ischemic injury should the anterior spinal artery be compromised between the foramen magnum and C8, the cervical watershed.
6Spinal Cord Paralysis Levels C1-C3All daily functions must be totally assistedBreathing is dependant on a ventilatorMotorised wheelchair controlled by sip and puff or chin movements is requiredC4Same as C1-C3 except breathing can be done without a ventilatorC5Good head, neck, shoulder movements, as well as elbow flexionElectric wheelchair, or manual for short distances
7C6Wrist extension movements are goodAssistance needed for dressing, and transitions from bed to chair and car may also need assistanceC7-C8All hand movementsAbility to dress, eat, drive, do transfers, and do upper body washesT1-T4 (paraplegia)Normal communication skillsHelp may only be needed for heavy household work or loading wheelchair into car
8T5-T9Manual wheelchair for everyday livingIndependent for personal careT10-L1Partial paralysis of lower bodyL2-S5Some knee, hip and foot movements with possible slow difficult walking with assistance or aidsOnly heavy home maintenance and hard cleaning will need assistance
9Treatment of Spinal Injuries No Current Effective TreatmentPrevention is Keyall current medical and surgical treatments aimed to prevent further injury to the spinal cord.
10Spinal Cord Injuries May occur with neck or back trauma Associated with blunt head trauma, especially when casualty is unconsciousCan occur with penetrating trauma of vertebral columnImproper handling may cause further injury
11Mechanisms of Spinal Injury HyperextensionHyperflexionCompressionRotationLateral StressDistraction
12PathophysiologyDamage – Begins centrally in grey matter and spreads centrifugally.Primary insult –B/W Time of injury and initial careSecondary insult – Delayed swellingContinued mechanical traumaLow perfusionEndogenous factorsInitial segmental loss can be withstood because only small portion of grey matter neuronal pool is involved.
13ASIA A: Complete: no motor or sensory function is preserved in the sacral segments S4-S5 ASIA B: Incomplete: sensory but NOT motor function is preserved below the neurological level and includes the sacral segmentsASIA C: Incomplete: motor function is preserved below the neurological level and more than half of key muscles below the neurological level have a muscle grade <3ASIA D: Incomplete: motor function is preserved w/ muscle grade > 3ASIA E: Normal
14Diagnosis and management of acute spinal cord injury Initial assessment and immobilizationResuscitation and medical managementRadiological diagnosticsAnaesthesia managementSurgical therapyPost op critical care management
15Initial assessment and immobilization *HistoryPain/paresthesiasTransient or persistent motor or sensory symptoms*Physical ExaminationAbrasions/hematomaTendernessInterspinous process widening
16Immobilize the casualty’s head and neck manually Apply a cervical collar, if available, or improvise oneSecure patient to short spine board if extracting from a vehicleSecure head and neck to spine board for extraction
17Transfer patient to long spine board as soon as feasible Logroll in unisonStabilize head and neck with sandbags or rolled blankets
18Secure casualty to long spine board with straps across forehead, chest, hips, thighs, and lower legs
19Resuscitation and medical management ATLS principles AirwayBreathingCirculatoryNeurologic ClassificationSpinal ImagingGastroIntestinal SystemGenitourinary SystemSkin
20Airway Risk Associated with Level of Injury Decision to Intubate Airway Intervention
21Risk Associated with Level of Injury cont’d Ventilatory FunctionC1 - C7 = accessory musclesC3 - C5 = diaphragm“C3-4-5 keeps the diaphragm alive!T1 - T11 = intercostalsT6 - L1 = abdominals
22Decision to Intubate:Need for Artificial Airway is Usually Related to Resp Compromise e.g.Loss of innervation of the diaphragm(C keep the diaphragm alive)Fatigue of innervated resp musclesHypoventilation – SaO2 <60, PaCO2 >45V/Q mismatch – PaO2/FiO2 <250Secretion retentionAtelectasis
23Decision to Intubate Related to Neurological Level Occiput - C3 Injuries (ASIA A & B)Require immediate intubation and ventilation due to loss of innervation of diaphragm
24Decision to Intubate Related to Neurological Level cont’d C4-C6 Injuries (ASIA A & B)Serious consideration for prophylactic intubation and ventilation if:Ascending injury (requires serial M/S assessment by a trained clinician)Fatigue of unassisted diaphragmInability to clear secretions
25Airway InterventionMaintaining Spinal PrecautionsSupine positionMaintain neutral C-spineRemove rigid collar and sandbagsManually stabilize C-spine2 person technique:1st person to provide manual in-line stabilization (not traction) of C-spine2nd person intubates
32Circulatory Spinal Shock Temporary suppression of all reflex activity below the level of injuryOccurs immediately after injuryIntensity & duration vary with the level & degree of injuryNeurogenic ShockThe body’s response to the sudden loss of sympathetic controlDistributive shockOccurs in people who have SCI above T6 (> 50% loss of sympathetic innervation)
33Hemodynamic Instability: Intervention First Line: Volume |Resuscitation (1-2 L)Second line: Vasopressors- (dopamine/norepinephrine) to counter loss of sympathetic tone and provide chronotropic support to the heart
34Hemodynamics and Cord Perfusion Options:Avoid hypotensionMaintain MAP 85-90mmHg for first 7 days if possible
35Bradycardia: Intervention Prevention:Avoid vagal stimulationHyperventilate and hyperoxygenate prior to suctioningPre-medicate patients with known hypersensitivity to vagal stimuliTreatment of Symptomatic Bradycardia:Atropine mg IV
36Neurological Classification Motor and sensory assessmentASIA Impairment Scale (A-E)Clinical Syndromes (patterns of incomplete injury)
37Spinal ShockAn immediate loss of reflex function, called areflexia, below the level of injurySigns:Slow heart rateLow blood pressureFlaccid paralysis of skeletal musclesLoss of somatic sensationsUrinary bladder dysfunctionSpinal shock may begin within an hour after injury and last from several minutes to several months, after which reflex activity gradually returns
38Central Cord Syndrome Usually involves a cervical lesion May result from cervical hyperextension causing ischemic injury to the central part of the cordMotor weakness is more present in the upper limbs then the lower limbsPatient is more likely to lose pain and temperature sensation than proprioceptionPatient may complain of a burning feeling in the upper limbsMore commonly seen in older patients with cervical arthritis or narrowing of the spinal cord
39Brown-Sequard Syndrome Results from an injury to only half of the spinal cord and is most noticed in the cervical regionOften caused by spinal cord tumours, trauma, or inflammationMotor loss is evident on the same side as the injury to the spinal cordSensory loss is evident on the opposite side of the injury location (pain and temperature loss)Bowel and bladder functions are usually normalPerson is normally able to walk although some bracing or stability devices may be required
40Anterior Spinal Cord Syndrome Usually results from compression of the artery that runs along the front of the spinal cordCompression of SC may be from bone fragments or a large disc herniationPatients with anterior spinal cord syndrome have a variable amount of motor function below the level of injurySensation to pain and temperature are lost while sensitivity to vibration and proprioception are preserved
41Cauda Equina Syndrome: Injury to the lumbosacral nerve roots w/ in the neurocanal resulting in areflexive bladder, bowel and lower limbs
42Spine Imaging the Asymptomatic Patient Option - Xray not needed in alert, sober, compliant patient without neck pain and tenderness or major distracting injuriesSymptomatic PatientStandard – Ap lat and odontoid viewOption – discontinue protection after….normal and adequate dynamic radiography, ornormal MRI within 48hrs of injury, orat the discretion of treating MD
43CT myelogram – Bony detail of fracture site, and anatomic relation of segment to spinal cord. MRI – anterior discs, ligamentum flava & cord contusion.
44cervical immobilization local cervical soft tissue swelling GI SystemRisk of aspiration is high d/t:cervical immobilizationlocal cervical soft tissue swellingdelayed gastric emptyingParasympathetic reflex activity is altered, resulting in:decreased gut motility andoften prolonged paralytic ileus
45GU Intervention – Catheterisation Skin Intervention – GI Intervention- Nasogastric tube IV H2 blockersGU Intervention – CatheterisationSkin Intervention –*Remove spine board*Turn or reposition individuals with SCI initially every 2 hours in the acute phase if the medical condition allows.
46Pharmacologic Therapy Methylprednisolone-controversial30mg/kg IV loading dose mg/kg/hr (over 23hrs) effective if administered within 8 hours of injuryIf initiated < 3hrs continue for 24 hrs, if 3-8 hrs after injury, continue for 48hrs (morbidity higher - increased sepsis and pneumonia)Thromboprophylaxis - LMWH, discontinued at 3months
47Secondary Interventions Without mechanical compression on CT myelogram – External stabilisationMean arterial pressures are kept b/w mmHg and CO kept ( N/ high N )Dopamine infusion may be necessary
48Anaesthesia Management Pre op assessmentMedical historyPremedication and pt. EducationAirway managementPositioningFluid requirementsSpecial intraop requirements(wake up test)Post op pain and pulmonary toilet
50Airway evaluationMP classification and range of neck mobility and elicitation of pain/ neurological symptomPulmonary evaluationDuring spinal shock (3 days – 6 wks)ABG- assess adequacy of ventilation, intubation if hypoxemia or hypercapnia (on O2 mask)Chronic stagePFT and Chest X ray – Restrictive pattern (FEV1&FVC)
51Severity of functional impairment related to – Angle of scoliosis, No of vertebrae, cephalad location of curve and loss of normal kyphosis.Respiratory function should be optimised –Treating infectionBronchodilationChest physiotherapy
52Cardiac evaluationECG – myocardial ischemiaCardiovascular instability evidenced by hypotension, hypertension, brady & arry. – assessment of cardiac reserve and to optimise circulatory volume according to cardiac function and peri. Vas. Tone.Pacemaker – persistently bardycardic.High spinal cord injury – initially spinal shock,autonomic dys,impaired LVF and later autonomic dysreflexia.
53Neurological evaluation Document preexisting deficitsNeurological dys may dictate intubation tech,monitoring and choice of agents.PharmacologyAltered P/K because of muscle wasting,inc volume of distribution,dec serum albumin
54Preop preparationHb, Hct, WBC and urinalysisOther tests indicated by historySE, BUN, Creatinine, PT,aPTT, Platelet count, ECG, Chest radiograph, ABG and PFT.Echo – to assess LV function pulmonary artery pressures and stress echo in sedentary patients
55PremedicationIf anxious IV midazolam Under supervisionAtropine if HR < 70 – Dose 0.04mg/kgH2 receptor blocker/ PPIInductionUnnecessary/ contraindicated for unconscious, recently injured patients with spinal cord trauma / those with severe shock.
56Technique of intubation Elective - fiberoptic intubationEmergency – MILS with rapid sequenceMaintenanceNitrous oxide, inhalation agent
57Positioning Goals Adequate surgical exposure Anatomic position of extremities & headAvoid abdominal pressureAdequate paddingVarious positionsa) Proneb) Supinec) Sitting (obsolete
58PRONE POSITION MOST COMMONLY USED EYES:Corneal abrasionOptic neuropathyRetinal artery occlusionHEAD & NECKVenous and lymphatic obstuctionABDOMENImpaired ventilationDecreased CO
59Monitoring Physiological Neurological Pulse oximetry Continuous ECG monitoringEtCo2CVPTemperatureUrine outputInvasive BPSwan Ganz catheter?NeurologicalWake up testSSEPTranscutaneus MEP
61Post op critical care management Indications for post op ventilation –Preexisting NM disorderSevere restrictive – VC <35%Obesity / RVFProlonged surgerySurgical invasion of thoracic cavityBlood loss > 30ml/kg
62post op contd Prepare for weaning Adequate nutrition and metabolic stateInfection – May be masked(Poikilothermia)Optimal fluid managementTreat mechanical impairment to breathing like abd distention, tight halo cast, positionPsychological preperation
63Cough – Glossopharyngeal breathing and huffing. Breathing exercises Post op contdChest Physiotherapy – Postural drainage, chest wall percussion and vibration, tracheal suctioning and breathing exercises.Cough – Glossopharyngeal breathing and huffing.Breathing exercises
64Perioperative complications of spine surgery Airway obstruction : edema, hematoma,recurrent laryngeal nerve palsy.Respiratory: motor paralysis and infection (pneumonia).Cardiovascular: hypotension, bradycardia, arrhythmias, hypertension ( spinal cord injury, carotid sinus stimulation).Neurological:Injury to nerve roots – as a result of direct surgicalmanipulationInjury to lower cranial nerves – VII, IX, X, XIIInjury to peripheral nerves - as a result of positioningInjury to spinal cord .
65f) Tracheal and oesophageal injury e) Vessel injury – vertebral and carotid artery duringdissectionf) Tracheal and oesophageal injuryg) CSF leaks - due to tear of dural and arachnoidmembranes can lead to meningitis, pseudomeningocoele, permanent CSF fistulah) DVT – seen in 30% of neurosurgical patients, especially those who had been paraplegic. Pulmonary embolism may occur
66Outcome Acute spinal injury who survive >24hrs,85%alive at 10years Most common causes of death-pneumonia, non-ischemic heart disease (occult autonomic dysfn), suicide (lifelong impact of injury)