2. Neuraxial Blockade involving injection of local anaesthetic in the
sub-arachnoid space
Spinal anesthesia can be classified as a failure if the surgical
operation cannot be performed without the addition of general
anesthetic or an alternative regional block
No blockade
Inadequate Block for the surgery
3. The incidence of failure with spinal
anesthesia varies in different studies,
ranging from 3% to 17%.
In some smaller studies, failure rates
as high as 30% have been reported
More among unsupervised trainees
8. Aim is to optimize the pt’s position
& prevent any movement
anxiolytic premedication
local anaesthetic infiltration at the
puncture site
9. Abolishing the natural lumbar lordosis by flexing maximally the whole
spine (including the neck), the hips, and knees increases the space
between the lumbar laminae and spines
Sitting or Lateral
Lateral Position
10. Sitting position confers the advantage of
making the midline easier to identify, particularly in obese
patients
increases hydrostatic pressure in the CSF, which may make
spinal needle placement and fluid aspiration easier
11. Approach
Midline approach
Can be angulated cephalad when resistance
is felt
Lateral/Paramedian approach- when the
ligaments are calcified
Mental picture of the spinal anatomy &
Appreciation of loss of resistance
12. Size 18 to 25G do not affect the
success rate
Thinner needles, greater tendency to
deviate, slower appearance of CSF in
the hub, more chances of failure
13. Opening is proximal to the tip to prevent PDPH
Small displacement can cause drug deposition in epi/subdural space
Opening is longer than in Quincke’s, resulting in dura acting as a flap valve
across the opening
14. Dry tap
The needle & stylet should be
checked for any block
Pseudolumbar puncture
Needle should not be
inserted without the stylet
15. A fully effective dose
should be both chosen
and actually deposited
in the CSF
DRUG
SOLUTION
INJECTION
ERRORS
16. Determines the quality & duration of the
block
Factors influencing intrathecal drug
spread & the LA drug
With low-dose, selective or U/L spinal
anesthesia, the proper technique more
important than with higher doses.
whole of the dose must be delivered into
the CSF, including the dead space of the
needle.
DOSE
SELECTION
17. Connection between
syringe and needle
provides a ready
opportunity for leakage
of solution
The syringe containing
the injectate must be
inserted very firmly into
the hub of the needle to
prevent such leaks
LOSS OF
INJECTATE
18. Anterior or posterior displacement of the needle tip, while
attaching the syringe to the needle
aspiration to confirm free flow of CSF
force of the injection of the syringe contents
Misplaced
injectionSubdural
injection
of drug
High sensory block,
sparing of
sympathetic & motor
Failure of block
19. Good fixation of the needle -prevents displacement
Rotation of the needle
20. • Kyphosis, or scoliosis
• Ligaments can form complete septae
within the theca acting as barriers to the
spread
• Spinal stenosis
• Sequelae of previous intrathecal
chemotherapy
• Cysts within the subarachnoid space-
saccular dilatations of the septum
posticum
Anatomical
Abnormalities
INADEQUATE
INTRATHECAL SPREAD
21. Lumbar CSF volume variability
• dural ectasia in marfan’s, & some connective
tissue disorders
Pre procedural USG can be of help in
identification & managament of difficult spinal
22. Iso & Hypobaric – spread is less predictable
If lumbar puncture is performed at L4-L5 or the lumbo-sacral interspace, the
LA may be ‘trapped’ below the lumbar curve (sitting posture)-saddle block
SOLUTION DENSITY
23. Identification
errors
Concentration
errors
Alkaline pH of
CSF altering pKa
of LA, bloody
tap
Loss of potency
Chemical
incompatibility
• Precipitation or
decreasing the
concentration of the
un-ionized fraction
Local
anaesthetic
resistance
INEFFECTIVE DRUG ACTION
24. Anxious patients
Requires good preoperative patient counseling followed
by a supportive approach, with intraoperative sedation
FAILURE OF SUBSEQUENT MANAGEMENT
25. Advisable to start testing in the lower segments, where
onset will be fastest, and work upwards.
Proving early on that there is some effect encourages
patient confidence; testing too soon does the opposite
26. Problems of inadequacy & duration can
be solved by using either continuous
spinal or combined spinal–epidural
techniques
Introducing a catheter may be difficult in
subarachnoid space
To Avoid misdirection of LA solution- not
more than 2-3cm in intrathecal space
29. Partial block No block
Reduced dose Full dose
It should be performed by an experienced
senior anaesthesiologist.
Preferably in a sitting position, to avoid high
spinal
In Partial block, the combination of the 2 doses
should not exceed that considered reasonable
as a single injection for spinal anesthesia
30. Advantages
• Simple to perform
• Avoids the complications
associated with GA
Complications
• Excessive cephalic spread,
Exaggerated hypotension
• Risk of direct nerve damage
• PDPH
• Multiple attempts- epidural
haemotoma
• If the initial failure-
anatomical reasons, Repeat
spinal- same effect
• Local anaesthetic toxicity
31. Aspiration of CSF should be attempted before & after injection of
anaesthetic
Sacral dermatomes should be included in evaluation of spinal block
If CSF is aspirated after anaesthetic injection – LA has been delivered
into Subarachnoid space
Avoid reinforcing the same restricted distribution
If CSF not aspirated after injection- tincture of time, carefully assess
the blockade and repeat full dose only if there is no evidence of block
32. Technique of choice
in Failed spinal
Unpreparedness
Difficult airway
Presence of comorbid
illnesses
Aspiration risk in
emergency
surgeries/CS
Hypotension due to
sympathetic blockade
due to SAB
Advantages:
Disadvantages:
33. Inadequate spread due to vertebral canal pathology-
R/O any signs & symptoms of Neurological disease
Investigating local anaesthetic effectiveness
When series of failures in a short period of time
Performing skin infiltration with some of the solution intended for
the spinal injection should demonstrate that it is effective
34. In 1907 Alfred E. Barker wrote that for successful spinal analgesia
it is necessary
‘to enter the lumbar dural sac effectually with the point of the
needle, and to discharge through this, all the contemplated dose of
the drug, directly and freely into the cerebrospinal fluid, below the
termination of the cord’ (Barker, 1907).
Failure to follow the details of this advice is the commonest cause
of a poor result
35. Cousins & Bridenbaugh’s Neural Blockade In Clinical Anaesthesia & Pain Medicine
Complications of Regional Anaesthesia, Brendan T. Finucane
Br. J. Anaesth. (2009) 102 (6):739-748.doi: 10.1093/bja/aep096First published
online: May 6, 2009
Pokharel, A. "Study of Failed Spinal Anesthesia Undergoing Caesarean Section and
Its Management." Post-Graduate Medical Journal of NAMS 11.02 (2011).
Analgesia & Anesthesia in Labor and Delivery By D. K. Baheti
Basics of Anesthesia, 6th Ed by Ronald Miller
Editor's Notes
, insertion should start precisely in the mid-line, mid-way between the posterior spines, with the needle shaft at right angles to the back in both planes
the specific local anaesthetic used, the baricity of that solution, the patient’s subsequent posture, the type of block intended, and the anticipated duration of surgery
reduces the risk of the membrane edges catching on the opening.
curves of the vertebral column are integral to solution spread
Improper mixing or excessive dilution
Resistance due to mutation of sodium ion channel
Rapid onset and profound block of spinal anaesthesia,
: Flex the hips & knee & give Head down tilt, or turning the patient onto the unblocked side in c/o Unilateral block, entonox inhalation in a parturient, local infiltration of the wound, supplementation with iv anaesthetics