spinal

1. Spinal and Epidural
Anaesthesia
• Presented By : Dr. Abhishek Joshi
(JR1, Anaesthesia)
• Moderator: Dr. Sonam Patel
Deptt. Of Anaesthesiology, Pain Medicine and
Critical Care Medicine, AIIMS, Gorakhpur.

2. History:
• First Spinal Anaesthesia in Humans: August Bier in 1898 using Cocaine.
• Lidocaine used by Gordh in 1949.
• Bupivacaine used by Emblem in 1966.
• Ropivacaine and Levo-Bupivacaine were introduced in 1980s.

3. • Lumber Epidural Anaesthesia in humans first described by Pages in 1921.
• Loss of resistance technique was given by Dogliotti in 1930s.

4. Epidural Anaesthesia:
• Instillation of local anaesthetic drug into the epidural space via a epidural catheter.
• An Epidural block can be performed at the Lumbar, Thoracic, Cervical and Caudal
level.
• Wide use of applications; Operative anesthesia, Obstetric Anesthesia & Analgesia,
Postop pain control and Chronic Pain Management.
• It can be used as a “Single Shot” or with a catheter that allows intermittent boluses
or a Continuous Infusion.

5. Embryology:
• Spinal cord and brain develop from neural tube which arises from the
ectoderm overlying the notochord.
• Cells from the mantle layer of neural tube forms the gray matter.
• Axons of the cells in mantle layer from the white matter in marginal layer.

6. Anatomy:
Lumbar Vertebra

7. Abnormal Curvatures of Spine:

8. Anatomy:
• The Epidural space surrounds the dura-mater posteriorly, laterally and anteriorly.
• It extends from foramen magnum to the sacral hiatus.
• Nerve roots travel in this space as they exit the spinal cord laterally.
• They then exit the foramen and travel peripherally to become peripheral nerves
carrying both afferent and efferent pathways.

9. Boundaries and
Spread of Drug:
• Epidural space bounded by:
• Anteriorly: Posterior longitudinal ligament
• Posteriorly: Ligamentum flavum ( extends
from foramen magnum to sacral hiatus)
• Laterally: Pedicles and intervertebral
foramen
• Supraspinous ligament extends from
external occipital protuberance to coccyx.

10. Blood Supply of Spinal Cord:

11. Layers Pierced in Epidural Anaesthesia:

12. Layers Pierced in Spinal Anaesthesia:
• Skin
• Subcutaneous fat
• Supraspinous ligament
• Interspinous ligament
• Ligamentum flavum
• Dura mater
• Arachnoid membrane

13. Termination of Spinal Cord:
• In Adults: Lower border of L1
vertebra
• Infants: L3 vertebra
• Dural puncture above these levels is
associated with risk of damaging the
spinal cord in respective age groups.
• Dural sac ends at S2 level.

14. Surface Anatomy:
• Inferior angle of scapula:
Spinous Process of T7
• Tuffier's line: Body of L4
vertebra
or L4-L5 interspace.

15. Spinal Block Physiology:
• Uptake of Local Anaesthetic by:
• Diffusion
• Via Virchow-Robin spaces

16. Physiology of Epidural:
 Possible sites of anesthetic action include:
1 Intra-dural spinal roots
2 Dorsal and Ventral spinal roots
3 Dorsal root ganglia
4 The Spinal Cord
5 The Brain itself (by diffusion)
6 Paravertebral nerve roots

17. Sensitivity of Nerve Fibres To LA:
B
Cold
Pin
Prick

18. Level of Anaesthesia:
• Differential sensory block,
1-2 Spinal Segments
𝐴𝑏fibres Touch sensation
1-2 Spinal Segments
𝐴𝑑fibres Pinprick sensation
(CEPHALAD)
B and C fibres Sympathetic and cold

19. Dermatomal Levels Required for Various
Surgical Procedures:
Corresponding to
Nipples
Nipples
Umbilicus
Umbilicus
Anterior Mid Thigh

20. Myotomes:

21. Motor Block Assessment - Bromage Scale:

22. Modified Bromage Scale:

24. Physiologic Effects of Neuraxial Blockade

25. Effect on Cardiovascular System:
• Blockade of peripheral T1-L2 sympathetic fibers.
• Venous and Arterial vasodilatation.
• Fall in both pre-load and after-load.
• Stroke volume decreases.
• Blockade of T1-T4 cardiac sympathetic fibers(during high neuraxial blockade).
• Heart rate decreases.
• Can lead to severe Bradycardia or even asystole.

26. Reduced
Cardiac
Output
Decreased
Stroke Volume
Decreased
Heart Rate
Blockade of
Adrenal Medullary
secretion

27. Effect on Respiratory System:
• Reduction in vital capacity because of reduced expiratory reserve volume.
• Because of blockade of abdominal and intercostal muscles.
• Adequately compensated by unaltered functioning of diaphragm and accessory
respiratory muscles.
• Although rare, respiratory arrest associated with spinal anaesthesia is often
unrelated to phrenic or inspiratory dysfunction but rather due to hypoperfusion of
respiratory centres in the brainstem.

28. Effect on Gastrointestinal System:
• Neuraxial blockade from T6 to L1 disrupts splanchnic sympathetic innervation.
• This leads to unopposed parasympathetic activity.
• Resulting in contracted gut and hyperperistalsis, causing nausea and vomiting in
upto 20% of patients.
• Atropine is effective in treating nausea associated with high subarachnoid
anaesthesia.

29. Effect on Renal System:
• The effect of neuraxial blockade is of little physiologic importance.
• It is believed that neuraxial blocks are a frequent cause of urinary retention as the lumbar
& sacral level both sympathetic & parasympathetic control of bladder function is
blocked.
• This delays discharge of outpatients and necessitates bladder catheterization in
inpatients.
• Excessive volumes of intravenous crystalloids shouldn’t be given to patient undergoing
spinal anaesthesia.

30. Indications of Neuraxial Blockade:
All surgical interventions below the umbilicus is the general guiding principle-
• Surgeries involving lower limb
 Inguinal hernia, Piles, fistulae & fissures
• Gynaecological procedures:
• Abdominal & vaginal hysterectomies
• Caesarean sections
• Open tubectomies

31. • Orthopedic surgeries on the pelvis, femur, tibia and the ankle.
• Urological procedures: Transurethral resection of the prostate,
ureterosigmoidostomy.
• Surgeries involving perineum and genitalia.

32. Indications of Epidural Anaesthesia:
• Epidural anaesthesia with or without sedation has been used as the sole anaesthetic or
as an adjunct to general anaesthesia (reduces patient’s requirement for opioid
analgesics).
• Labour analgesia
• Chronic benign pain- Cervical & lumbar radiculopathy, vertebral compression
fracture, degenerative disc disease, peripheral neuropathy, low back pain.
• Cancer related pain- Pain secondary to shoulder, genital, pelvic, perineal etc.
malignancy & chemotherapy related peripheral neuropathy.

33. Contraindications of Neuraxial Blockade:
• Absolute:
• Patient refusal
• Infection at the site of injection
• Coagulation disorders/bleeding
diathesis
• Severe hypovolemia/septic shock
• Raised intracranial pressure
• Allergy to planned spinal drug.
• Relative:
• Pre-existing neurological disorder
• Aortic stenosis or fixed cardiac output
• Hypovolemia
• Abnormalities of spine
• Uncooperative patient

34. Common LA Used for Epidural Anaesthesia:
 Bupivacaine:
• 0.125-0.25% for analgesia
• 0.5% for anaesthesia
 Ropivacaine:
• 0.1 - 0.2% for analgesia
• 0.5-1% for anaesthesia
 Lidocaine:
• 2% for anaesthesia
 Levobupivacaine:
• 0.5 -0.75% for anaesthesia
• 0.125-0.25% for analgesia

35. Common LA Used for Spinal Anaesthesia:

36. Factors affecting Block Height:

37. Technique for Spinal Anaesthesia:
• Patient can be positioned either in sitting or lateral flexed position.
• Approaches:
1: Median - Spinal needle is introduced in the midline over the desired
intervertebral space.
2: Paramedian - Needle is introduced 1.5 cm lateral to the midline at an angle of
25 degrees with the midline.

38. 3: Taylor Technique -
• Needle is introduced 1 cm
medial and 1 cm inferior to the
lowest prominence of posterior
superior iliac spine.
• Spinal needle is directed
upwards, medially and forwards
at an angle of 50 degrees to the
skin.

39. Technique for Epidural Anaesthesia:
Position of patient- Careful attention to the patient’s position is essential to successful
placement of the epidural needle and catheter.
Depending on the patient’s medical status, weight, and ability to cooperate, the sitting or
lateral decubitus position can be used.
Easier in sitting position.
Approach - Four common approaches to the epidural space are possible:
1. Midline,
2. Paramedian,
3. Taylor (modified paramedian),
4. Caudal

41. Locating the Epidural space:
• All aseptic precautions are taken.
• Skin is infiltrated with local anesthetic in to desired space.
• Needle is advanced slowly, feel of increase resistance.
• 3 methods are used to identify Epidural space-
 Loss of resistance (to with air or saline):-As needle reaches Epidural space
Loss of Resistance is felt

42. LORS Vs LORA:
• LORA is associated with nerve root compression, pneumocephalus
and greater incidence of incomplete analgesia, paresthesia and
venous air embolism.
• LORS is associate with reduced incidence of dural puncture in adult,
while in pediatric patients, dural puncture incidence are more.

44.  Hanging drop method:-As needle reaches Epidural space Hanging drop is
sucked in d/t negative pressure.
 In cervical region, negative pressure poorly reliable and only useful in sitting
position.
 The negative intra-thoracic pressure may influence the pressure in epidural
spaces in thoracic region and should be maximal during inspiration.
Ultrasonography / Fluoroscopy

46. Test Dose:

47. Spinal Needles:
• Has 3 parts:
• Needle
• Stylet
• Hub
• Sizes ranging from 16 to 30 gauge.
• Can be divided into two categories:
• Dura cutting
• Dura splitting

48. Dura Cutting
Dura Splitting

49. Epidural needle:
 Epidural needles have larger diameter than Spinal
needle.
 Typically sized of 16-19 gauge.
1 Tuohy & Hustead needle –with gently curve of 15-30° degree.
2 Crawford needle- with straight tip.

51. Types of epidural catheter:
Single –end hole catheter Closed tip, multiple-
side hole catheter
Spring wire-reinforced
catheter

52. Catheter placement:
• The catheter is made of a flexible, calibrated, durable, radiopaque plastic .
• Typically, 19-or 20- gauge catheter is introduced through 17-or 18- gauge epidural
needle.
• Catheter is threaded through needle after placing in space.
• Needle is withdrawn over the catheter.
• 4-6 cms catheter remain in epidural space. Threading more catheter may increase the
likelihood of catheter malposition.
• Catheter is firmly secured to skin with surgical tape.

53. Catheter Placement:

54. Complications:
• Drug Related Complications-
• CNS toxicity
• CVS toxicity
• Procedure Related Complications-
• Minor Back Pain
• Post-dural Puncture Headache
• Subarachnoid Injection/High or Total Spinal
• Sheering of catheter

55. • Neurologic Complications-
• Spinal nerve neuropathy
• Transient neurological symptoms
• Anterior spinal artery syndrome
• Adhesive arachnoiditis
• Epidural hematoma
• Epidural abscess

56. Postdural Puncture Headache :
• Due to inadvertent dural puncture.
• Frontal or occipital headache.
• Worsen with upright/seated posture.
• Spontaneous resolution in 7 days.
• Conservative Management:
• Supine positioning.
• Hydration.
• Caffeine and oral analgesics.
TOC – Epidural blood patch: Ideally performed 24 hours after dural puncture.

59. Advantage:
 Minimise effect of surgery on Cardiopulmonary reserve.
 Patient with compromised Respiratory system
 Morbid obesity
 COPD
 Elderly
 Earlier mobilization
 Decreased chances of DVTE

60.  Effective analgesia without taking systemic opioids(analgesics are given through
catheter).
 Surgery induced Stress response is decreased
 Blood loss is less and
 Everything can be regulated and changed by:
1. Choice of drug
2. Concentration of LA
3. Dosage
4. Level of Injection

61. Disadvantage:
Risk of block failure
Onset is slower
Risk of infection
Epidural hematoma
Continuous epidural catheter should not be used in the ward if monitoring is not
proper.

62. Difference between spinal and epidural anesthesia:
Spinal Anaesthesia Epidural Anaesthesia
Level: below L1/L2, where the spinal cord ends Level: at any level of the vertebral column.
Injection: subarachnoid space i.e. puncture of the Dura mater Injection: epidural space (between Ligamentum flavum and
dura mater) i.e without puncture of the dura mater
Identification of the subarachnoid space: When CSF appears Identification of the Epidural space: Using the Loss of
Resistance technique.
Onset of action: rapid (2-5 min) Onset of action: slow (15-20 min)
Hypotension: rapid Hypotension: slow
Headache: is a probably complication Headache: is not a probable complication.

63. Caudal Epidural Anesthesia:
• Common regional technique in infants, neonates and pediatric patients.
• For lower abdominal and genitourological procedures
• In adults, it is usually reserved for procedures requiring blockage of the
sacral and lumbar nerves, epidurography, for lysis of adhesions in
patients with low back pain with radiculopathy after spinal surgery,
cancer pain-bony metastasis in pelvis or chemotherapy related
peripheral neuropathy.

64. • Positions :
Lateral decubitus- mainly paediatric
Prone- mainly in adults
Knee-chest position
• Point of Entry is the Sacral Hiatus.
• Two ways of locating sacral hiatus:
1. Locate the posterior superior iliac spines. A line drawn between them becomes
one side of a equilateral triangle. At the apex of the triangle is the sacral hiatus.

65. 2.With firm pressure, identify the coccyx with the index finger.
As the finger moves cephalad, the first pair of bony protuberances are
the cornu, which surrounds the hiatus.

66. Combined spinal-epidural anesthesia:
• Introduced in 1939 when Soresi et al presented a paper on usage of CSE in
200 patients.
• Technique combining both spinal and epidural.
Spinal component gives rapid onset and dense predictable block.
Epidural catheter is used to supplement insufficient subarachnoid block (to
increase height or duration of block) and also to provide long-lasting
analgesia.

67. Reduces the incidence of several potential problems associated with the
conventional epidural technique, including incomplete (patchy) blockade, motor
block, and poor sacral spread.
The sequential CSE technique may be particularly advantageous in high-risk
patients, such as in those with cardiac disease, when slower onset of sympathetic
blockade is desirable.
• Two approaches are mostly used:
1. Needle Through Needle
2. Needle Below Needle.