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Complications of neuraxial block

Complications of neuraxial block. Professor Lester AH Critchley Dept. Anaesthesia & Intensive Care Prince of Wales Hospital The Chinese Unversity of Hong Kong. Complications include: [neuraxial = subarachnoid & epidural]. Technical failure Pruritis / urinary retention / nausea

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Complications of neuraxial block

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  1. Complications of neuraxial block Professor Lester AH Critchley Dept. Anaesthesia & Intensive Care Prince of Wales Hospital The Chinese Unversity of Hong Kong Complications of neuraxial block

  2. Complications include:[neuraxial = subarachnoid & epidural] • Technical failure • Pruritis / urinary retention / nausea • Cardiovascular • Hypotension • Bradycardia, asystole & cardiac arrest • Post dural puncture headache • Neurological deficit • Transient / Permanent Complications of neuraxial block

  3. “The most feared complication of neuraxial block is neurological deficit (paraplegia).” Fortunately, this complication is very rare” Not just a complication of anaesthesia. Medicine – (neurology) Lumbar puncture - Diagnostic / Therapeutic Radiology Mylograms Neurological deficit Complications of neuraxial block

  4. Trauma (needle or injection) Neurotoxicity Coagulopathy Infectious complications These issues have been addressed by three recent concensus conferences (by Am. Soc. Reg. Anesth.) Summarize causes: Complications of neuraxial block

  5. Moore & Bridenbaugh paper • Retrospective study of 11,574 spinal anaesthetics between 1948 – 1960. • 3000 – upper abdominal surgery (inc. Whipples) • LA agent – tetracaine ±adr/PE (lasted up to 12h) Complications: • Deaths (n=4) – Cardiac arrest (v, sick patients) • Hypotension – high incidence • Headaches (n=163: 1.4%) • Nerve palsies (n=17) Complications of neuraxial block Moore. JAMA 1966:195:907

  6. Peripheral nerve palsies (n=17) Complications of neuraxial block Moore. JAMA 1966:195:907

  7. Aetiology of neurological complications that arise from regional block Closed claims nerve injuries associate with anaesthesia Complications of neuraxial block

  8. Causes of nerve injury other than Anaesthesia • Surgical operations • Patient positioning • Pre-existing disease • Others (tourniquets) • In hand surgery - 3.4% of 533 pts. nerve injuries • (of which 2% relate to block) • In shoulder arthroscopy – <30% transient neuropraxia of the brachial plexus & musculocutaneous n. most at risk. • Stretching & irrigation fluid Complications of neuraxial block

  9. Neurological injuries associated with obstetric anaesthesia Complications of neuraxial block

  10. Clinical practice point: • Important when problems occur: • Thorough neurological examination • Documentation in the notes Complications of neuraxial block

  11. History to spinal anaesthesia & neurological complications • 1885: Corning discovered “spinal anaesthesia”. • 1898: The first spinal anaesthetic for surgery in humans was give by Bier. • In Kiel Germany using 0.5% cocaine, but later abandoned the technique (side effects). • 1900s: A number of spinal anaesthetic agents were developed. • The most significant was procaine. • But side effects and occasional fatalities limited its popularity. • 1923: Labat published his “Regional Anesthesia” • He advocated the use of procaine. • 1940’s: spinal anaesthesia remained popular; • Because of the high quality operating conditions it provided. • 1950’s: the popularity of SA waned and GA increased because of: • The introduction of neuromuscular blocking agents Complications of neuraxial block

  12. Early reports of complications.Causes not determined. Complications of neuraxial block

  13. Safety record of spinal anaesthesia was good pre-1950 considering: • Lack of iv fluid loading • No non-autoclaved needles • That surgeons gave their own spinals. • Used for upper abdominal surgery • even thoracoplasty, thyroidectomy and craniotomy Complications of neuraxial block

  14. The dangers of intrathecal medication. J.A.M.A. (July 30, 1949). “the intrathecal space is so frequently chosen for the administration of serums, drugs, antibiotics (penicillin & streptomycin) and anesthetic agents that it is sometimes forgotten that numerous serious and tragic sequelae have been reported following the use of this route… The introduction of each new therapeutic agent into the intrathecal space has been inevitably followed by reports of serious damage to the nervous system.” The grave spinal cord paralyses caused by spinal anaesthesia Report to the American Neurological Association (New York) Kennedy. Surgery, Gynecology and Obstetrics. 1950:91:385. The dangers of intrathecal medication. Complications of neuraxial block

  15. Chesterfield church spire • Chesterfield Royal Hospital in 1947 • Albert Woolley (aged 56-years) and Cecil Roe (aged 45-years) were healthy, middle-aged men who became paraplegic after spinal anaesthesia for minor surgery. • The spinal anaesthetic was given by the same anaesthetist, using the same drug (cinchocaine) on the same day. The outcome for the patients and their families was devastating. • At the trail 6-years later the judge accepted the suggestion that phenol, in which the ampoules of local anaesthetic had been kept, had contaminated the local anaesthetic solution via a crack. Complications of neuraxial block

  16. Subsequent explanation:Maltby. Brit J Anaesth 2000:84:121. • Subsequent explanation has suggested that the acid descaling liquid used in the sterilizing pan for the needles and syringeshad not been replaced by water. This contaminated the syringes and needles used to draw up the anaesthetic solution, which was then injected intrathecally. • Unknown to the court there was a third patient very ill from intestinal obstruction who received spinal anaesthesia that day who died a few days later. He probably also suffered neurological sequelae after spinal anaesthesia. • The theatre nurse responsible had been ill with violent headaches that day and later had pituitary tumour removed. Complications of neuraxial block

  17. The court case • The Phenol via crack in ampoule theory, proposed by Professor MacIntosh and accepted by the judge, was rejected by the neurologist (Macdonald Critchley) and the Anaesthesist. • Roe (the patient) at trail reported having an intra-operative headache (not post operative) which occurred immediately following the injection of local anaesthetic solution. This would be consistent with a chemical contaminant. • The case was presided over by Lord Denning. It had a major impact on subsequent medical law regarding litigation for medical misadventure. Complications of neuraxial block

  18. Impact on British anaesthetic practice • Spinal anaesthesia was not routinely practiced in Britain for over 20 years following the Woolley & Roe case. • The technique was lost to a generation of anaesthetists. • It was not reintroduced until the late 1970’s. Complications of neuraxial block

  19. True incidence rate:“serious neurological injury following neuraxial block” Is not known Complications of neuraxial block

  20. Incidence of serious complications (neuraxial block) Complications of neuraxial block

  21. Complications related to regional anaesthesia:Survey of all regional anaesthetics in France over a 5 month period in 1997. [≈1 in 10:000] Complications of neuraxial block Auroy. Anesthesiology 1997:87:479

  22. Complication of spinal and epidural block in Finland Inurance claims over 7-year period (1987-1993) Complications of neuraxial block Aromaa. Acta Anesthesiol Scand 1997:41:445

  23. Breakdown of US closed claim reports of neurological injury Complications of neuraxial block Cheney. Anesthesiology 1999:90:1062

  24. Syndromes & termsassociated with neuraxial block • Radiculopathy • Paraplegia • Cauda equina syndrome • Arachnoiditis (adhesive) • Anterior spinal artery syndrome • Tethered cord syndrome (congenital) • Cerebral complications: • Intracranial haematoma • Cranial nerve palsy Complications of neuraxial block

  25. Radiculopathy • Hypoaesthesia & occasional weakness area supplied by nerve root. • If transient: • TNS - Transient neurological symptoms • TRI - Transient radicular irritation • Often associated with paraesthesia during block or pain on injection Complications of neuraxial block

  26. “Alarm events” • Incidence of paresthesia during spinal block 6.3% • [298 / 4767] Horlocker. Anesth Analg 1997:84:578 • Definate association: • paresthesia / pain = post op neurological complications • Pain on needle insertion • Pain on injection of drug • Should procedure be aborted if paresthesia occurs? • Recommendation – do things “slowly” Complications of neuraxial block

  27. Cauda Equina Syndrome • Usually due to cord compression in lumbar region, but can be due to damage to conus and lower nerve roots. • Onset immediately following spinal block, with persistent urinary and fecal incontinence, and localized sensory loss / pain in the perineal region and varying degrees of leg weakness. • Symptoms may be permanent or gradually regress over weeks or months. • Causes: • Dysfunction of the L2-S5 roots. • Bladder atony / anal incontinence (S3-S4) • Sensory loss - saddle area (L5-S1) • Weakness / paralysis of muscles under the knee Complications of neuraxial block

  28. Arachnoiditis(adhesive) • Incidence 1 : 10,000 to 25,000 • Inflammatory disorder of arachnoid mater. • Chemical damage - preservatives (sodium metabisulphate, methylparaben) or disinfectants. • Usually occurs several weeks or months after spinal anaesthesia. • Gradual progressive sensory deficits and motor weakness in the lower limbs, which may progress to complete paraplegia. • MRI - adhesive arachnoiditis • (There is a proliferative reaction of the meninges and constriction of the spinal cord blood supply). • “Arachnoiditis the silent epidemic” Complications of neuraxial block

  29. Anterior spinal artery syndrome • Arterial blood supply of the spinal cord: • Anterior 2/3 – ant. spinal a. (Adamkiewicz artery ) • left intervertebral foramen between T8 and L3 from aorta • Aorta - limited anastomosis • Post 1/3 - two posterior arteries • Arise from the lumbar and cervical regions. • Loss the anterior supply: • Pyramidal, anterior & lateral spinothalamic tracts • Flaccid paralysis, loss of pain and temperature sensation. • Sparing of post columns (position sense). • Causes: • arteriosclerosis / intra-op hypotension / vasoconstrictors in LA. Complications of neuraxial block

  30. Intracranial haematoma • Very rare and less well recognized complication. • Incidence rate 1:500,000 • Presumed mechanism is puncture, loss of CSF, traction and damage to cerebral vascular structures. • Contributing factors: • Difficult puncture, • preexisting cerebral atrophy, • Chronic alcoholism. • Persistent headache often misdiagnosed PDPH. • Need a CT scan. Complications of neuraxial block

  31. Cranial nerve injuries secondary to neuraxial block Complications of neuraxial block Day. Reg Anesth 1996:21:197 (Case review)

  32. Summary of Cranial n. palsy • Sporadic cases that effect ocular, auditory and facial function. • Not life threatening, generally resolve spontaneously in a few days or weeks. • Likely to cause anxiety to the patient if not explained. Complications of neuraxial block

  33. Functional anatomy of nerves: • Fascicles held together by the epineurium (an enveloping external connective tissue sheath of the nerve) • Each fascicle contains many nerve fibres and capillary blood vessels embedded in endoneurium (loose connective tissue). • Each fascicle is surrounded by the perineurium (multilayered epithelial sheath). • Nerve fibres are dependant on the endoneurium environment. • The capillary blood flow is regulated by the sympathetic ns. • Functions (i) conduct nerve impulses, (ii) maintain axon transport [proteins, precursors for receptors & transmitters] • Dependant on oxidative metabolism • Structures can be deranged by trauma, including intraneural injection. to the nerve with loss of function. Complications of neuraxial block

  34. Causes of neurological injury (Neuraxial block) [Added complexity of the spinal canal] • Cord & nerve root damage • direct trauma (needle & injection) • neurotoxicity • Cord ischaemia • Interruption to blood supply • Cord compression • Haematoma • Abscess • Meningitis • Intracranial lesions Complications of neuraxial block

  35. Symptoms of nerve injury • Manifest after block has receded, within 48h • Spectrum of symptoms: • Light intermittent tingling and numbness lasting a few weeks • Persistent painful painful paresthesia, sensory and/or motor loss • Evolve into causalgia • (or reflex sympathetic dystrophy) Complications of neuraxial block

  36. Guidelines of NYSORA (peripheral block) 2006 • Choice of needle (bevels, length) • Needle advancement (slowly) • Proper functioning nerve stimulators • Fractional injections (3-5 ml) • Avoid forceful, fast injections • Avoid injection under high pressure • Severe pain or discomfort on injection (warning) • Chose your local anaesthetic wisely • Avoid blocks in anaesthetized patients • Avoid repeating blocks after failed block Complications of neuraxial block

  37. Trauma & neuraxial block Risk of Needle insertion causing permanent paralysis Complications of neuraxial block

  38. Direct Trauma by spinal needle • 7 cases where neurological damage followed spinal or CSE. (6 were obstetric). • All patients experienced pain during needle insertion. Insertion level was “believed to be” L2-3 interspace. • A 25 or 27 G Whitacre (atraumatic needles) & CSF flowed freely (n=7). Successful block (n=6). • unilateral sensory loss L4-S1, (n=7), • foot drop (n=6), • urinary symptoms (n=3). • MRI scan showed “syrinx” & damage in the conus (n=6). Complications of neuraxial block Reynolds F. Anaesthesia 2001:56:238

  39. Magnetic resonance imaging scan of the lumbar spinal from case 1.(a) The sagittal view shows cord and epidural fat as white and fluid as dark. The cord ends at the lower border of L1. A dark cleft is visible in the substance of the cord, which also appears as a dark spot on the right of the midline in (b), the axial image at T12. Complications of neuraxial block Reynolds F. Anaesthesia 2001:56:238

  40. Discussion: • Clear evidence of needle trauma to conus (6/7). • Tip of conus usually lies at L1-2. • Anaesthetists incorrectly identifying lumbar interspaces by ±2 spaces. • (Even when using Tuffier’s line). • Broadbent C. Anaesthesia 2000:55;1106. • Conclusion: • Restrict level of needle insertion to L4-5. • “Avoid upper lumbar interspaced at all times” • Why the cluster of cases? Complications of neuraxial block

  41. Thoracic EpiduralThere have been a few reported cases of spinal cord injury following thoracic epidural. Common feature in many of these cases was that the epidural was sited after induction of anaesthesia. Complications of neuraxial block

  42. Guidelines – Thoracic Epidural placement:Case in Germany of paraplegia following thoracic epidural. Prompted vigorous debate & guidelines: • No epidurals should be inserted above L1-2 in the anaesthetized patient. • There should be careful consideration of the risk: • [i.e. a thoracic epidural would not be justifiable in upper abdominal procedures such as a cholecystomy in an otherwise healthy patient] • Insertion of lumbar epidurals and spinals should only be performed in anaesthetized patients in exceptional circumstances. Complications of neuraxial block Grüning. Anaesthesia. 1999:54:86.

  43. Key points:Trauma as cause • Level of needle insertion • Justifying thoracic epidurals • Needle insertion in the anaesthetized patient • the lack of “alarm event” Complications of neuraxial block

  44. Neurotoxicity & neuraxial block Risk of injected drugs causing permanent paralysis Complications of neuraxial block

  45. Neurotoxicity of intrathecal drugs:“Neurological complications following neuraxial block is not new.” • Data back to before the 1950’s • Reports of severe neurological consequences lead to: • (i) large follow up studies and • (ii) the abandonment of the technique. • In the UK spinal block was abandoned for +20y • a whole generation anaesthetists did not perform spinals. • Woolley & Rose case • Not just the drugs / sterilizing agents, etc Complications of neuraxial block

  46. Development of methods to evaluate local anaesthetic toxicity • Self experimentation (early pioneers) • Clinical experience • Animal studies of Toxicity (only recently) • Perform spinal puncture & inject different agents • Tail flick test • Paw stimulation test • Anal tone • Kill the animal & perform histological examination of the spinal cord • Sample “glutamate” via microdialysis catheters in CSF • Bull frog sciatic nerve (demylinated) • Histological classification of neural injury: • Nerve injury • Damage to myelin sheath • Inflammatory change to arachnoid cells Complications of neuraxial block

  47. Which local anaesthetic agents are used intrathecally world wide ? • Bupivacaine (0.5% heavy solution) • & various Enantiomers • Amethocaine • also called - Tetracaine, Pontocaine. • Lignocaine 0.5% to 5% • also called - Lidocaine, Xylocaine. • Ropivacaine • 2-chloroprocaine Complications of neuraxial block

  48. Lignocaine toxicityBackground: • Spinal Lignocaine became very popular for ambulatory surgery. • Lignocaine 5% (heavy) was thought to be safe. • Review of 10440 cases. (Phillips. Anesthesiology 1969:30:284.) • Early 1990’s reports appeared - permanent neurological complications when using lignocaine 5% & microcatheters. • Intrathecal micro-catheters stopped being used • Spinal lignocaine 5% for ambulatory surgery continued • Reports of transient neurologic symptoms (TNS) at 24h • Back pain • Pain or abnormal sensations in the buttocks or legs • Also called transient radicular irritation (TRI) Complications of neuraxial block

  49. Experience with spinal Lignocaine 5% (Case reports) Complications of neuraxial block

  50. Incidence of TNS in ambulatory ASA 1-2 patients (from randomized studies rather than epidemiological data): Complications of neuraxial block

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