Protection of the spinal cord with cerebrospinal fluid

drainageChristos Apostolidis, Md, EDAIC, MSc

Anaesthetist

Risk factors

• extent and location of the aneurysm

• Emergency surgery

• aortic dissection

• prior aortic abdominal surgery

• age

• level and length of aortic cross-clamping

• Involvement of the Adamkiewicz a

Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/

AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM executive summary

Strategies

• CSF drainage

• High MAP/ fluctuations of the SAP

• Hypothermia

• Intercostal aa reimplantation

• Pharmacologic adjuncts (papaverine, steroids, mannitol, free radical

scavengers, excitatory neurotransmitter inhibitors, naloxone)

• minimizing spinal cord ischemic time

• increasing its tolerance to ischemia

Interact Cardiovasc Thorac Surg 2017;24:708–13

Spinal cord, Basic facts

• SCPP=MAP-CSFP (or CVP, whichever is greater)

• Thoracic aorta occlusion causes increase in CSF pressure and decrease in distal perfusion pressure

• MAP is a surrogate of the collateral network after clamping

• Autoregulation: SAP 50 to 125 mmHg

• During hypoxia or hypercarbia, autoregulation is lost, and flow becomes linearly related to perfusion pressure.

• Maintain High MAP (90mmHg), low-normal CSFP (10mmHg)

Contraindications

• ASRA Guidelines

- Antiplatelet use (clopidogrel #5-7d, NOACS 3-5d)

- Infection at the site of puncture

- Previous surgery/ trauma at the site

- Increased ICP

Complications

• Epidural/ subdural haematoma

• Headache

• CSF leak

• Subarachnoid haemorrhage

• Meningitis

• Neurologic deficit

British Journal of Anaesthesia, 120 (5): 904e913 (2018)

Epidural haematoma

• Anatomic abnormalities of the spinal cord or vertebral column

• Vascular abnormalities

• Bleeding Diathesis

• Alcohol abuse

• Chronic renal insufficiency

• Difficult and traumatic needle placement

• Epidural catheter removal

Signs of spinal haematoma

• Low back pain (sharp and may radiate)

• Sensory and motor loss

• Bowel and bladder dysfunction

• Paraplegia

Bloody tap, alert surgical team

The catheter set

CSF drainage: the method

The procedure

• Side lying position

• Sterile site prep of the lumbar spine

• Needle insertion at L3-L4 or L4-L5 into intrathecal space

• Clear Cerebrospinal fluid free flow confirmed

• Catheter advanced 5-7cm and secured

• Occlusive Dressing applied

• Transducer connected and leveled at the right atrium (tragus)

• CSF drained to <10mmHg

Suggested strategy

CSF management

No consensus, individual/ institutional preferences

CSF pressure 8-12mmHg perioperatively

15-25ml/h

ICU checklist

• Transduce Cerebrospinal Fluid Pressure (CSFP)

• Position patient Head up 30°

• Level transducer to phlebostatic axis or right atrium

• Continuously transduce CSFP

• Stopcock always off position

• Read waveform on end expiration

• Document the CSF pressure every 1 hour for 3 days

• If CSF >10mmHg drain to <10mmHg or no more than 15ml

ICU checklist

• 24-48h draining

• 24h capping before removal (72h)

• Neurologic evaluation before removal

• Cautious anticoagulation, once daily LMWH: 12h after/ 2-4h before next dose (ASRA guidelines)

• Clinical neurologic evaluation up to 72h after removal

• Bed rest for 12-24h, vigilance for diplopia, photophobia, headache, nausea, tinnitus, seizures, evident CSF leak

• Maintain optimal Saturation

• Maintain Hemoglobin >9mg/dl

• Maintain Cardiac Index >2.5

• Maintain SBP >140 mmHg and its’ fluctuations

Thank you

Blood supply

• Complex

• Interindividual variability

• ASA supplying motor areas:

- vertebral aa (originating from subclavian aa)

- Intercostals

- Adamkiewicz (lower thoracic) forms the greater radicular a

• PSAs supplying sensory/ proprioceptive areas

2 critical perioperative periods

1. Temporary interruption of spinal cord blood supply long enough to irreversibly damage cell bodies and nerve tracts in the spinal

cord

2. Postoperatively, as a consequence of a permanent

reduction in blood supply: sacrifice of critical blood vessels (thoracic or

intercostal and lumbar segmental arteries)

Eur J Cardiothoracic Surg 2014;47:943–

57

Maximizing tolerance: Agents

• Proposed mechanisms: reduction of inflammation, edema, cytotoxic mediators, cell metabolism, oxygen demand, vasodilation

• Weak evidence

• high-dose systemic glucocorticoids, osmotic diuresis with mannitol, intrathecal papaverine, and cellular metabolic suppression with anesthetic agents may be considered intraoperatively to increase the tolerance of the spinal cord to impaired perfusion (IIb, LOE B)

ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and

management of patients with thoracic aortic disease. Anesth Analg2010;111:279–315

Minimizing ischaemia time

• Multisegmental, sequential aortic reconstruction

• Stepwise, staged sequential clamping of the aneurysm (if anatomy permits to do so)

• early distal unclamping technique to restore pulsatile flow to the internal iliac artery

Interact Cardiovasc Thorac Surg 2017;24:708–13.

Minimizing Ischaemiatime: left heart

bypass

• Lower anticoagulation needs (no oxygenator/ heart-cooler)

• Adequate cardiac function (increase in afterload)

• OLV

• flow preferentially diverted to the lumbar part of the anterior spinal artery

Maximizing tolerance: Hypothermia

• The only intervention shown to be reliably effective in protecting the spinal cord from ischemia during the absence of blood flow

• Deep hypothermia with circulatory arrest, moderate hypothermia with circulatory support, mild hypothermia with native circulation

• Local cooling (epidural saline 4°C)

J Thorac Cardiovasc Surg 2013;145:S56–8

Spinal cord injury: the problem

• 5-20% of patients• Permanent paraplegia/ paraparesis 2-3%• Immediate, or delayed events (days/ weeks)• Complex/ multifactorial mechanisms• Both open and endovascular repairs

Coselli JS, Lemaire SA, Preventza O, et al. Outcomes of 3309 thoracoabdominal aortic aneurysm repairs. J Thorac Cardiovasc Surg 2016;151:

1323–38

Pathophysiology of SC injury

Important facts

• Adaptable circulation

• Support SC perfusion in the days following the procedure

• Relevance of staged procedures

• Aortic cross clamping involves mainly the ASA

• Motor deficits

• Motor nn more prone in ischemia/ reperfusion

Eur J Cardiothoracic Surg 2014;47:943–

57

Collateral Network: Guardian angel

• Multilevel longitudinal interconnections

• Subclavian, hypogastric, ITAs

• Axial network (vertebral, epidural, etc)

• Resilience of SC after insults

• Steal phenomena