Spinal anesthesia involves injecting local anesthetic into the subarachnoid space to reversibly block sensory and motor function below the injection site. It has several advantages over general anesthesia for certain surgeries, providing anesthesia without airway manipulation. Common complications include hypotension from sympathetic blockade and post-dural puncture headache from a cerebrospinal fluid leak at the injection site. Proper patient positioning, choice of needle and drug, and fluid management can help reduce complications of this technique for lower abdominal, urogenital and lower extremity surgeries.

1. SPINAL ANESTHESIA
PRESENTOR : DR VORUGANTI NIKHIL KUMAR

2. INTRODUCTION
Spinal anesthesia involves the
use of small amounts of local
anesthetic injected into the
subarachnoid space to
produce a reversible loss of
sensory and motor function

3. ANATOMY
VERTEBRAL COLUMN CONSISTS OF
7 CERVICAL VERTEBRAE
12 THORACIC VERTEBRAE
5 LUMBAR VERTEBRAE
5 SACRAL VERTEBRAE
4 COCCYGEAL VERTEBRAE
The spinal cord is enclosed in the vertebral
column, It extends from the foramen magnum
where it is continuous with the medulla to the level
of the L1 in adults and around levels L3 in infants
5 The spinal cord terminates in a tapering cone
shaped structure called as conus medullaris

4. CAUDA EQUINA
Cauda equina refers to the bundle of
nerve roots located at the lower end
of the spinal cord, which extend
beyond the termination of the spinal
cord at the first lumbar vertebra.
The cauda equina exists within
the lumbar cistern, a gap between
the arachnoid membrane and the pia
mater of the spinal cord, called
the subarachnoid space

5. Therefore, performing a lumbar
(subarachnoid) puncture below L1 in
an adult (L3 in a child) usually avoids
potential needle trauma to the cord
And damage to the cauda equina is
unlikely, as these nerve roots float in
the dural sac below L1 and tend to be
pushed away (rather than pierced) by
an advancing needle

6. LAYERS OF SPINAL CORD
SKIN
SUBCUTANEOUS TISSUE
SUPRA SPINOUS LIGAMENT
INTERSPINOUS LIGAMENT
LIGAMENTUM FLAVUM
EDPIDURAL SPACE
DURA MATER
ARACHNOID MATER
SUBARACHNOID SPACE
PIA MATER

8. DERMATOMES
A DERMATOME IS A AREA OF SKIN INNERVATED BY
SENSORY FIBRES FROM A SINGLE SPINAL NERVE
•Cervical nerves. There are eight pairs of these
Cervical nerves, numbered C1 through C8. They
originate from your neck.
•Thoracic nerves. You have 12 pairs of thoracic
nerves that are numbered T1 through T12
•Lumbar nerves. There are five pairs of lumbar spinal
nerves, designated L1 through L5.
•Sacral nerves. Like the lumbar spinal nerves, you
also have five pairs of sacral spinal nerves.
•Coccygeal nerves. You only have a single pair of
coccygeal spinal nerves.

9. DERMATOMAL LEVEL OF SPINAL ANESTHESIA
FOR COMMON SURGICAL PROCEDURES

10. INDICATIONS
Lower abdominal surgeries
Inguinal surgeries
Urogenital surgeries
Rectal surgeries
Lower extremity surgery

11. ABSOLUTE
• 1) Infection at the site of injection
• 2) Patient refusal
• 3) Coagulopathy or other
bleeding diathesis
• 4) Severe hypovolemia
• 5) Increased intracranial pressure
• 6) Severe aortic stenosis or Severe
mitral stenosis
• 1)Sepsis
• 2) Uncooperative patient
• 3)Preexisting neurological deficits
• 4)Demyelinating lesions
• 5)Stenotic valvular heart lesions
• 6)Left ventricular outflow obstruction
• 7)Severe spinal deformity
RELATIVE
CONTRAINDICATIONS

12. DURA SPLITTING
• Whitacre needle
• Sprotte needle
• Quincke babcock needle
• Pitkin needle
DURA CUTTING
SPINAL NEEDLES

14. POSITIONS
SITTING POSITION LATERAL DECUBITUS POSITION
TUFFIERS LINE

15. APPROACHES OF SPINAL
ANESTHESIA
1)Midline Approach - The most common approach, the
needle or introducer is placed midline, perpendicular to
spinous processes, aiming slightly cephalad .
2)Paramedian Approach - Indicated in patients who can
not adequately flex because of pain or whose ligaments
are ossified, the spinal needle is placed 1.5 cm laterally
and slightly caudad to the center of the selected
interspace.

16. MIDLINE APPROACH
The most common
approach, the needle or
introducer is placed
midline, perpendicular
to spinous processes,
aiming slightly cephalad

17. PARAMEDIAN
APPROACH
Indicated in patients who
can not adequately flex
because of pain or whose
ligaments are ossified, the
spinal needle is placed 1.5
cm laterally and slightly
caudad to the center of
the selected interspace.

18. DRUGS USED IN SPINAL ANESTHESIA
LIDOCAINE
Onset of action occurs in 3 to 5 minutes
with a duration of anesthesia that lasts for
1 to 1.5 hours
Rapid onset of action , intermediate
duration and low toxicity
Disadvantages — Transient neurological
symptoms

19. BUPIVACAINE
One of the most widely
used local anesthetics
Onset of action is
within 5 to 8 minutes,
with a duration of
anesthesia that lasts
from 90 to 150 minutes

20. OTHER DRUGS USED IN
SPINAL ANESTHESIA
•Tetracaine 0.5%
•Mepivacaine 2%
•Ropivacaine 0.75%
•Levobupivacaine 0.5%
•Chloroprocaine 3%

21. ADJUVANTS USED IN SPINAL ANESTHESIA
Produce intense visceral analgesia and prolong only sensory blockade
1)Opioids - Lipophilic agents such as fentanyl and sufentanil have a much more localized effect
,rapid onset of action and an effective duration greater than 6 hours.
2)CLONIDINE-alpha 2 agonist (150ug)
Onset -same
Duration-prolonged
3)Epinephrine- vasoconstrictor action delays absorption of local anesthetic
4)Phenylephrine-1:1,000 concentration

22. MECHANISM OF ACTION
I. Interacts with the receptor situated within the
voltage sensitive sodium channel and raises
the threshold of channel opening
II. Decreases the entry of sodium ions during
upstroke of action potential
III. Local depolarization fails to reach the
threshold potential and conduction block is
acheived

23. LEVELS OF BLOCK
SYMPATHETIC
PARALYSIS
SENSORY
BLOCK
MOTOR
BLOCKADE

25. COMPLICATIONS OF SPINAL ANESTHESIA
INTRA OPERATIVE COMPLICATIONS POST OPERATIVE COMPLICATIONS
1) HYPOTENSION
2) RESPIRATORY IMPAIRMENT
3) TOTAL SPINAL BLOCK
4) NAUSEA AND VOMITING
1) POST DURAL PUNCTURE HEADACHE
2) INFECTIONS

26. PHYSIOLOGIC EFFECTS OF
SPINAL CORD

27. AUTONOMIC BLOCKADE
The sympathetic nervous system (SNS) is described as
thoracolumbar since sympathetic fibers exit the spinal cord
from Tl to L2.
The parasympathetic nervous system (PNS) has been described
as cranio sacral since parasympathetic fibers exit in the cranial
and sacral regions of the CNS.
The end result of neuraxial blockade is a decreased sympathetic
tone with an unopposed parasympathetic tone. This imbalance
will result in many of the expected alterations of normal
homeostasis noted with the administration of spinal anesthesia.

28. CARDIO VASCULAR EFFECTS
Spinal blockade can impact the
cardiovascular system by causing the
following changes:
1)Decrease in blood pressure (33%
incidence of hypotension in non-obstetric
populations)
2)Decrease in heart rate (13% incidence
of bradycardia in non-obstetric
populations)

29. RESPIRATORY EFFECTS
Spinal blockade plays a very minor role in altering pulmonary
function.
Even with high thoracic levels of blockade, tidal volume is
unchanged.
There is a slight decrease in vital capacity. This is the result of
relaxation of the abdominal muscles during exhalation.
The phrenic nerve is innervated by C3-C5 and is responsible for
the autonomic movement of diaphragm.
The phrenic nerve is extremely hard to block, even with a high
spinal, apnea associated with a high spinal is thought to be
related to brainstem hypoperfusion and not blockade of the
phrenic nerve. This is based on the fact that spontaneous
respiration resumes after hemodynamic resuscitation has occurred

30. RENAL EFFECTS
Neuraxial blockade effectively blocks spinal control of the bladder at the lumbar
and sacral levels
Urinary retention can occur due to the loss of autonomic bladder control.
Detrusor function of the bladder is blocked by local anesthetics. Normal function
does not return until sensory function returns to S3

31. MANAGEMENT OF COMMON COMPLICATIONS
OF SA
• HYPOTENSION
• Increase the rate of administration of IV
fluids
• Oxygen supplementation until BP restores
back to optimal levels
• Vasopressors
• Ephedrine sulphate
• Mephenteramine
• Phenylephrine
• Epinephrine
• Norepinephrine
• BRADYCARDIA - Administer Atropine
• Respiratory impairment or Total
Spinal - Intubate and ventilate the
patient with 100% Oxygen

32. POST DURAL PUNCTURE HEADACHE
Post dural puncture headache
is a common potential
complication of a lumbar
puncture, with symptoms
caused by traction on pain-
sensitive structures from low
cerebrospinal fluid pressure
(intracranial hypotension)
following a leak of
cerebrospinal fluid at the
puncture site

33. PDPH
Incidence -10% to 40% of LP procedures, but can be as low
as 2% when small gauge (less than or equal to 24 gauge)
non-cutting needles are used
It is postural and it is often fronto-occipital associated with
stiff neck , nausea, vomiting , dizziness and photophobia.
Pathophysiology-Loss of CSF at a faster rate than it can be
produced causing traction on the structures supporting
brain, particularly dura
It is aggravated by sitting or standing and decreased or
relieved by lying down Flat.

34. MANAGEMENT
o CONSERVATIVE MANAGEMENT - BED REST , HYDRATION , ANALGESICS , ANTI EMETICS
AGGRESSIVE MEDICAL MANAGEMENT - THEOPHYLLINE, CAFFEINE ,OCCIPITAL NERVE BLOCK
EPIDURAL BLOOD PATCH
RECONSIDER DIAGNOSIS , FIBRE GLUE SURGERY

35. ADVANTAGES OF SPINAL ANESTHESIA
1. 1)Cost - The costs associated with SPA are minimal.
2. 2)Respiratory disease - Spinal anesthesia produces few
adverse effects on the respiratory system as long as
unduly high blocks are avoided.
3. 3)Patent airway - As control of the airway is not
compromised, there is a reduced risk of airway
obstruction or the aspiration of gastric contents
4. 4)Diabetic patients-There is little risk of unrecognized
hypoglycemia in an awake patient.

36. REFERENCES
MORGAN AND MIKHAIL CLINICAL ANESTHESIOLOGY - 6TH EDITION
MILLERS ANESTHESIA - 9TH EDITION
NYSORA
BJA
COLLINS REGIONAL ANESTHESIA

37. THANK YOU
ANY QUESTIONS ?