combined spinal epidural anesthesia

1. Combined spinal–epidural
Misganaw M
 mengiemisganaw@rocketmail.com
University of Gondar
College of medicine and health
science
SCHOOL OF MEDICINE
DEPARTMENT OF ANAESTHESIA

2. INTRODUCTION
 The combined spinal–epidural technique (CSE)
has become increasingly popular in recent years.
 It can be defined as the intentional injection of drug
into the subarachnoid space and the placement of a
catheter into the epidural space as part of the same
procedure.

3. CONTI…
 CSE allows
 a rapid onset of neuraxial blockade, which can
subsequently be prolonged or modified.
 Ideally it combines the best features of spinal
blockade (rapid onset, profound blockade, low drug
dosage) and epidural blockade (titratable levels, ability
to prolong indefinitely)

4. CONTI…
 and avoids their respective disadvantages (spinal:
single-shot nature, unpredictable level of blockade
 epidural: missed segments, incomplete motor
block, poor sacral spread, local anaesthetic toxicity)
 it is a more complicated technique than either block
alone and produces a multicompartment block

5. CONTI…
 CSE cannot be considered as simply a spinal block
followed by an epidural block.
 New complications and reasons for technical failure
are encountered.
 Epidural injection may modify the spinal block and
epidural drugs may not behave as they would without
prior dural puncture

6. APPLICATIONS OF CSE TECHNIQUES
 CSE was first described in the modern era for
urological surgery .
 More recently it has become an established
technique for analgesia in labour and anaesthesia
for Caesarean section .
 Obstetric anaesthesia and analgesia have
generated most reports of the technique

7. CONTI…
 It is regarded by some as the optimum regional
technique for nonobstetric surgery and has been
used for
 orthopaedic ,
 trauma ,
 general ,
 vascular and gynaecological surgery .
 It has also been used for paediatric anaesthesia .

8.  CSE is the technique of choice for determining
minimum intrathecal drug doses and for assessing
the interaction between intrathecal and epidural
drugs.

9. EPIDEMIOLOGY
 There are few data on use of the technique prior to
this decade.
 In 1992, Rawal surveyed hospitals in 17 European
countries .
 CSE use varied between countries, representing
0.2% (Ireland) to 60% (Holland) of major regional
blockade.
 Most use was for major orthopaedic and lower
abdominal surgery.

10. EPIDEMIOLOGY
 Also in 1992, in the same 17 European countries, CSE
was used for Caesarean section by 8% of
respondents.
 In 1993, in Sweden, two-thirds of departments used
CSE and up to a third of lower limb arthroplasty
surgery was performed using CSE anaesthesia .
 In 1997, 28% of Canadian anaesthetists reported
using CSE for labour analgesia . It has been estimated
that use of the CSE increased 10-fold between 1992
and 1997

11. TECHNIQUES OF NEEDLE INSERTION AND
VARIATIONS
 Several CSE techniques are described, probably in
part because no single technique is entirely
satisfactory.
 Techniques have been varied and modified in order
to increase success and avoid potential or actual
complications.

12.  Soresi described performing epidural injection and
then advancing the same needle into the
subarachnoid space .
 Sprotte described a similar technique in which a
needle was placed in the epidural space and
remained there while blockade developed.
SINGLE PASS

13. SINGLE PASS
 If blockade was inadequate, the needle was
advanced and subarachnoid injection performed.
 No catheters were used and it is difficult to imagine
what advantages these techniques have over pure
subarachnoid blockade.

14.  This is the most widely used CSE technique.
 An epidural needle is used to identify the epidural
space.
 A spinal needle is then passed through the epidural
needle into the subarachnoid space and the
subarachnoid block performed.
 After the removal of the spinal needle, an epidural
catheter is placed that can be used subsequently.
NEEDLE-THROUGH-NEEDLE

15.  Potential problems with needle-through-needle
CSE include:
 failure of the spinal component, inadvertent
insertion of the catheter into the subarachnoid
space and
 damage to either of the needles through friction
between them.

16.  The technique may be performed with a normal
epidural needle and a long spinal needle.
 Developments of this technique have included the
design of epidural needles with
 ‘backeyes’ or holes in the greater curvature of the
needles
 which allow the epidural catheter to be inserted away
from the dural puncture site, thus reducing the risk of
inadvertent subarachnoid placement of the epidural
catheter.

17.  Other developments include the design of spinal
needles which lock onto the epidural needle after
dural puncture, thus reducing the risk of spinal
needle displacement during intrathecal injection
and failure of spinal anaesthesia.
 Identification of dural puncture Because of the long
thin needles used, dural puncture may be difficult to
feel during needle-through-needle CSE.

18.  The needle-through-needle technique can also be
performed by inserting a catheter into the epidural
space before the spinal block.
 However, this technique risks damage to the epidural
catheter as the spinal needle is inserted.

19.  Conventional needle-through-needle CSE
necessitates epidural catheter insertion after
subarachnoid block, which could cause neural
damage since warning signs, such as paraesthesia
are lost.
 To avoid this inserting a 29 G spinal needle into a
16 G Tuohy needle, fixing it, then without removing
it, inserting an epidural catheter through the same
needle.

20.  This technique allow an epidural test dose to be
given before subarachnoid injection but are
technically complicated.

21. SEPARATE NEEDLES
 This technique uses two separate needles to
perform the spinal and epidural components of the
CSE.
 Both needles can be inserted at the same vertebral
interspace or at two separate interspaces. Again,
the spinal and epidural components of the CSE can
be performed in either order..

22.  The advantages and risks of performing the
epidural component first are the same as those
described for the needle-through-needle technique
above.
 The advantage of performing the spinal component
first is that the almost instantaneous onset of
analgesia reduces the risk of the patient moving
during the subsequent insertion of the epidural
needle

23.  Studies comparing the needle-through-needle
technique with the separate needle technique have
found a higher rate of failure of the spinal
component with the needle-through-needle
technique.
 Failure rates of 5–20% have been reported for the
needle-through-needle technique compared with
<5% for the separate needle technique.

24. DOUBLE-BARRELLED NEEDLES
 Certain CSE needles have been designed with two
barrels: one for the performance of the spinal
component and the other for the passage of the
epidural catheter. These needles allow the
separation of the sites of dural puncture and
epidural catheter placement. However, there are
few studies of the efficacy of these needles and
they are not commonly used.

25. COMPARISONS BETWEEN TECHNIQUES LOW DOSE
(‘SEQUENTIAL CSE’) VS. FULL DOSE CSE
TECHNIQUES
 a two-stage CSE whereby an intentionally small
subarachnoid dose is administered accepting that a
low block may occur. This is then ‘toppedup’ with
epidural drugs 15–20 min later.
 Epidural top-ups act rapidly after CSE and allow
prompt elevation of block level when it is too low.

26.  This ‘sequential CSE’ technique allows neuraxial
blockade to be restricted to the lowest level needed and
minimises sympathetic blockade.
 This makes the technique theoretically suitable for
patients with cardiac disease or at risk of hypotension.

27. CONT…
 The technique has also been used to study the
minimum dose of intrathecal local anaesthetic
suitable for ambulatory anaesthesia and Caesarean
section.
 The disadvantage of the technique is that adequate
blockade takes longer to produce than with full
doses making it unsuitable for urgent surgery

28. CSE VS. EPIDURAL OR SPINAL BLOCKADE
 CSE raised sensory thresholds more than spinal
or epidural block alone .
 CSE can therefore produce a physiologically
denser block than either technique alone.
 Epidural or spinal anaesthesia for Caesarean
section is inadequate in up to 4% of cases.
 It is suggested that CSE might reduce the risk of
conversion of regional to general anaesthesia to
0.16%

29. COMPLICATIONS
 The complications of CSE can be divided into
those related to the technique or those related to
the drugs administered.
 Failure of spinal component
 Failure of epidural component
 Misplacement or migration of epidural catheter
 Damage to spinal needle or catheter
 Subarachnoid spread of drug

30. COMPLICATIONS
 Neurological damage
 Paraesthesia
 Subdural haematoma
 Cauda equina syndrome
 Aseptic meningitis
 Post-dural puncture headache
 Infection
 Bacterial meningitis
 Abscess (epidural, subdural)

31. FAILURE OF THE SPINAL COMPONENT
 Failure of the spinal component of CSEs is more
common with the needle-through-needle
technique than with the separate needle
technique.
 In the case of the needle-through-needle
technique, failure of the spinal component can
occur for a number of reasons.

32.  A short spinal needle may not protrude far enough
beyond the tip of the Tuohy needle to pierce the
dura.
 On the other hand, a long needle may be more
difficult to handle.
 Deviation from the midline will also increase the
epidural–dural distance and may result in the spinal
needle missing the subarachnoid space laterally.

33.  If ‘loss of resistance to saline’ has been used to
identify the epidural space, backflow of saline
through the spinal needle may be mistaken for
cerebrospinal fluid, which may contribute to failure
of the spinal component

34. FAILURE OF THE EPIDURAL COMPONENT
 There are few studies on the rates of failure of the
epidural component.
 Occasionally, problems may be encountered with
inserting an epidural catheter following the spinal,
resulting in a significant delay between the spinal
and epidural components of the CSE.

35.  Such delays may result in the spinal component of
the block becoming ‘fixed’ before the anaesthetist
has had a chance to position the patient.
 Furthermore, significant side-effects of the
subarachnoid block (e.g. hypotension) may occur at
a time when the anaesthetist's attention is centred
on attempting to insert the epidural catheter.

36. SUBARACHNOID PLACEMENT OR MIGRATION OF
THE EPIDURAL CATHETER
 When the epidural component of the CSE is
performed after the spinal component,
 there is a risk of the epidural catheter being
accidentally inserted into the subarachnoid space
via the hole in the dura created by the spinal
needle.
 The risk is greatest with a needle-through-needle
technique.
 Backeyes’ may reduce the incidence

37.  Migration of the epidural catheter through the dura
after the CSE has been performed is an ever rarer
event.
 During epidural top-ups keeping this complication in
mind.

38. DAMAGE TO THE SPINAL NEEDLE OR EPIDURAL
CATHETER
 risk of friction between the spinal and epidural
needles with needle-through-needle CSE.
 This may generate metallic fragments.
 Can be introduced into the epidural or subarachnoid
spaces.
 spinal needle tip to be sheared off completely.
 .

39.  If an epidural catheter is placed before
introduction of the spinal needle,
 there is risk of damage to the catheter from contact
with the spinal needle during its insertion.

40. SUBARACHNOID SPREAD OF EPIDURALLY
ADMINISTERED DRUGS
 With the CSE technique, a dose of local anaesthetic given
epidurally will produce a higher dermatological block than
expected because of subarachnoid spread of the drug.
 this is not usually a clinically significant problem
unless the dura has been breached by the epidural
needle, or large epidural boluses are used.

41.  When the epidural component is performed after
the spinal component of CSE, epidural test doses
should be interpreted with caution because of this
subarachnoid spread.

42. NEUROLOGICAL DAMAGE
 It is very rare complication.
 The vast majority of these complications are minor
with no long-term effects.
 Paraesthesia on spinal needle insertion occurs
more commonly but, again, is rarely associated
with any long-term neurological damage.
 There have been reports of more serious
complications after CSE such as subdural
haematoma, cauda equina syndrome, aseptic
meningitis

43. POST-DURAL PUNCTURE HEADACHE
 Reportes ranged from 0.8 to 2.5%
 CSE would be associated with a higher incidence of
headache because of CSF leak from the site of
intentional dural puncture.
 CSE may also be associated with a lower incidence
of accidental dural puncture when compared with
conventional epidurals

44. INFECTION
 There have been case reports of bacterial
meningitis, epidural abscess, and subdural abscess
after CSE.
 The majority of these occurred after the use of CSE
in labour.
 There is no evidence that one particular CSE
technique is better than another in terms of risk of
infection.