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Introduction
e last 30 years have seen an explosion in research and
publications on pain in childhood and adolescence. Attention
has focused on several aspects including the developing
nociceptive system, acute, persistent, procedural and cancer
pain management.
Growth and development distinguish children from adults.
Clinically, an appreciation of the physiological, anatomical
and psychosocial developmental changes during childhood is
important in the assessment and management of pain.
Neurodevelopmental Aspects
e structural components necessary for pain perception start
to form at about 17 weeks and become established from 26
weeks’ gestation [54]. Pituitary-adrenal, sympatho-adrenal
and circulatory stress responses to physical insults have
been demonstrated in the human foetus from 18–20 weeks
[53]. Noxious stimulation causes detectable stress response
in the foetus from at least 23 weeks’ gestation [64]. ere
is debate whether hormonal stress responses and withdrawal
reflexes to invasive procedures prove the existence of foetal
pain, as they can be elicited by non-painful stimuli and occur
without conscious processing [91]. Noxious stimulation (heel
lance) is transmitted to the preterm infant cortex from 25
weeks [141]. Opioid receptors are abundant in the foetal
spinal cord and brain stem by 20 weeks [95, 129]. ere
is evidence that intravenous fentanyl attenuates the foetal
response to intrahepatic needling [53]. ese observations
have implications regarding surgery in premature neonates,
late abortion and foetal surgery.
INTRODUCTION
NEURODEVELOPMENTAL ASPECTS
PHARMACOLOGICAL ASPECTS
ANATOMICAL CONSIDERATIONS
HISTORICAL BACKGROUND
DO NATIONAL GUIDELINES
IMPROVE PAIN MANAGEMENT?
PAIN ASSESSMENT
ACUTE PAIN MANAGEMENT
Drugs
Regional blocks and use of local
anaesthetics
Special considerations (burns and
cerebral palsy)
PROCEDURAL PAIN
MANAGEMENT
PERSISTENT PAIN MANAGEMENT
A WORLD PERSPECTIVE
Pain in Children and Adolescents
19
George CHALKIADIS
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312 George CHALKIADIS
Laboratory studies in rats have shown that the
immaturity of sensory processing within the
newborn spinal cord leads to lower thresholds for
excitation and sensitisation. Foetal spinal cord
sensory neurones that respond to noxious stimuli
have larger receptive fields than in adults [55].
Endogenous descending inhibitory pathways are
not fully developed until mid-infancy raising the
possibility that neonates may be more sensitive to
noxious stimuli than older children. e plasticity
of both peripheral and central sensory connections
in the neonatal period means that early damage
in infancy can lead to prolonged structural and
functional alterations in pain pathways that may
persist into adulthood [16]. Clinically, increased
saliva cortisol [154] and pain behaviour [151, 154]
have been demonstrated in response to vaccination,
in neonates circumcised without analgesia or born
by difficult delivery.
Pharmacological Aspects
e administration of analgesic drugs in
children requires careful pharmacokinetic and
pharmacodynamic considerations. e neonatal
period and early infancy are periods of rapid growth
and development. Pharmacokinetic analyses allow
the use of size as the primary co-variate, and
have enabled exploration of the effects of age,
facilitating the comparison of neonatal data with
adult data [7]. Generally, clearance increases with
age, necessitating care with dosage in neonates and
young infants.
Anatomical Considerations
In neonates and young infants, the epidural fat is
spongy and gelatinous in appearance with distinct
spaces between individual fat globules. With
increasing age, fat becomes more tightly packed
and fibrous [157]. e clinical implications of
this difference in anatomy, is that an epidural
catheter can be inserted via the caudal route and
easily threaded cephalad, so that the tip lies in the
thoracic epidural space [23].
Historical Background
of Pain Management in
Children
For many years, children were denied adequate
pain relief due to outmoded beliefs including that:
• Newborn infants do not experience pain
[128]
• Children rarely require drugs for pain [150]
• Pain is merely a symptom, and not necessarily
harmful in itself [14]
• Effective analgesia makes diagnosis difficult or
impossible [68, 86]
• Effective analgesia delays discharge from
hospital
• Pain is an inevitable consequence of surgery
• Pain relief is dangerous.
ese beliefs in turn led to variability in prescribing
practices [100]:
• Postoperative analgesia was frequently not
prescribed
• Prescribed doses were too small or too
infrequent.
Compounding these issues, prescribed analgesia was
administered by unpleasant routes (intramuscular
or rectal) that led to children refusing pain relief.
Pain assessment and analgesia were low priorities
for hospitals, surgeons, anaesthetists and nurses
[67]. Most importantly, no health care provider
was accountable for poor analgesia.
Along with changing attitudes of paediatric
anaesthetists to pain relief [43], the mid-1980s saw
the establishment of paediatric pain services in the
United States, the United Kingdom, Australia and
France to facilitate the administration of effective
analgesia to children utilising more sophisticated
techniques [21]. ese improvements in pain
management have not been adopted worldwide,
even among developed nations. A recent survey of
383 German anaesthesia departments of hospitals
in which paediatric surgery was performed revealed
that 20.9% never administered intravenous opioids
to children and that 15.4% regularly prescribed
intramuscular analgesia [144].
In lesser developed countries, lesser standards
and reduced availability of anaesthesia and
postoperative nursing care along with cultural
attitudes to opioid analgesia make it less likely that
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Pain in Children and Adolescents 313
effective continuous infusion analgesic techniques
are used. Nevertheless, the more widespread use of
single-shot nerve blocks and caudal epidural blocks
in combination with balanced oral analgesia have
the potential to improve postoperative analgesia for
children undergoing minor surgery.
Do National Guidelines
Improve Pain Management?
Although national guidelines on pain management
[114, 155, 164] may influence the accreditation
of hospitals for training [180], they do not ensure
the commitment of all hospitals [70, 126]. In the
USA, the Joint Commission on Accreditation
of Healthcare Organizations (JCAHO) is an
independent not-for-profit organisation that sets
health care standards. e JCAHO standards
require that hospitals assess, treat and document
patients’ pain, guarantee the competence of their
staff in pain assessment and management, and
educate patients and families about effective pain
management [123]. Adherence to these standards
determines in part, accreditation of health care
facilities. It would seem that the most effective
way to effect organisational change is, therefore, to
institute standards which hospitals must adhere to in
order to achieve and maintain accreditation. ese
standards indicate strongly that the assessment and
treatment of acute pain is no longer optional. It is a
basic standard of care.
Pain Assessment
Many centres have adopted pain assessment as the
fifth vital sign, requiring nurses to assess pain and
document this on the main observation chart. is
increases the likelihood that adequate analgesia is
administered to children in pain.
A variety of pain assessment tools is available [35,
146]. Composite tools incorporating physiological
and behavioural indicators (CRIES and PIPP) are
available for premature and term neonates [103],
while behavioural scales such as the FLACC (faces,
legs, activity, cry and consolability) observational
pain tool can be utilised in infants and cognitively
intact preverbal children [107]. e revised FLACC
has shown reliability and validity postoperatively
in children with cognitive impairment [96]. More
complex tools are available to assess pain in children
and adolescents with cognitive impairment [26]. In
older cognitively intact children, self-report scales
such as the Faces Pain Scale — revised [71], Wong-
Baker Faces Pain Scale [182], visual analogue scales
(e.g. 10-cm horizontal or vertical line or numerical
rating scales (0–10)) can be used.
For an individual institution, it is most important
to select appropriate pain assessment tools that
are culturally relevant and which can be used to
assess pain in neonates, preverbal children, those
with cognitive impairment and older children
capable of self-report. Standardisation of the tools
adopted in any given institution facilitates nurse
and medical staff education, and communication
about pain. e Wong-Baker Faces Pain Scale,
visual analogue scale and Faces Pain Scale Revised
have been assessed in ai children and showed
moderate to good correlation and moderate
agreement [115].
Acute Pain Management
In developed countries, intramuscular injections
have become outmoded. Multimodal analgesia is
utilised to optimise analgesia in the perioperative
setting. Strong analgesia is indicated after major
surgery, trauma or children with cancer pain.
Generally, this may include alone or in combination,
intravenous opioid infusion, intravenous ketamine
infusion, a regional technique, intermittent oral
or intravenous tramadol, oral or intravenous
paracetamol and non-steroidal anti-inflammatory
drugs (NSAIDs). As pain decreases, these
analgesics can be gradually weaned. Most patients
are discharged with weaker analgesics such as
paracetamol, ibuprofen and tramadol if required.
Analgesics commonly prescribed in paediatric
patients and their dosage regimens are summarised
in Table 19.01.
Drugs for acute pain
Paracetamol
Paracetamol is the first-line analgesic for mild to
moderate pain in children. Clearance increases with
postconception age [4] from 27 weeks (1.87 l.h
-1
per
70 kg) to reach 84% of the mature value (16.3 l.h
-1
)
by 12 months of age [8, 184]. As paracetamol may
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314 George CHALKIADIS
Table 19.01 Commonly used analgesic drug doses
Drug Dose Cautions
Paracetamol 15 mg/kg q6h (max 90 mg/kg/day) in
children >44 wks postconception age
12.5 mg/kg q6h in premature neonates
32–36 wks postconception age
10 mg/kg q6h in premature neonates
28–32 wks postconception age
Prescribe according to lean body
mass
Use with caution in patients with
elevated liver enzymes, jaundice,
glutathione depletion, malnutrition
Codeine 0.5–1 mg/kg q4h Poor metabolisers
Oxycodone 0.1–0.2 mg/kg q4h
Morphine IV bolus dose: 0.05–0.1 mg/kg
PCA bolus 20 mcg/kg, lockout 5 min,
background 5 mcg/kg/h
IV infusion: 10–40 mcg/kg/h
Hydromorphone PCA bolus 2–4 mcg/kg, lockout 5 min,
background 1–2 mcg/kg/h
Fentanyl Intraoperative bolus: 1–5 mcg/kg
IV infusion up to 1.2 mcg/kg/h with 0.3
mcg/kg bolus q5min prn
PCA bolus 0.3 mcg/kg, lockout 5 min,
background 0.3 mcg/kg/h
Dose >1 mcg/kg may cause apnoea
Remifentanil Initial bolus: 1 mcg/kg
Infusion: 0.05–0.2 mcg/kg/min
Ketamine (analgesia) 10–40 mcg/kg/h by infusion
Ibuprofen 10 mg/kg q6h
Diclofenac Oral: 1 mg/kg q8h
Rectal: 0.5 mg/kg q12h
Naproxen 7 mg/kg (max 500 mg) q12h
Indomethacin Oral: 0.25–1 mg/kg q8h
Rectal: 1 mg/kg q12h
Ketorolac IV: 0.2 mg/kg (max 10 mg) q6h Ensure adequate hydration
Parecoxib 0.5 mg/kg
Bupivacaine
Levobupivacaine
Ropivacaine
2.5 mg/kg single shot
Infusion up to 0.4 mg/kg/h
Limit continuous infusion to 0.20
mg/kg/h to 36 hours’ duration in
children <6 months
Tramadol 1-2 mg/kg 6h prn
Amitriptyline Up to 1 mg/kg Prolonged QT syndrome
Gradually increase dose to avoid
side effects
Gabapentin Starting dose 10 mg/kg tds Start gradually — once daily day 1,
bd day 2, tds day 3
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Pain in Children and Adolescents 315
cause hepatotoxicity, it is important to calculate
dosage according to lean body mass.
e bioavailability of paracetamol is reduced
after rectal administration. Paracetamol has been
shown to undergo slow and irregular absorption
after rectal administration. e formulation of
the suppository is important with lipophilic
formulations undergoing more rapid absorption
than hydrophilic ones. Bioavailability after rectal
administration decreases with age. Neonates have
bioavailabilty close to 1 compared with 0.54 in
older children [11].
Peak plasma concentration of paracetamol after
oral administration occurs after 30 minutes. ere
is a lag time of around 60 to 90 minutes before
it reaches its effect site [6]. e oral preoperative
administration of paracetamol 1 hour prior to
minor procedures increases the likelihood that it
exerts its peak analgesic effect as the child emerges
from anaesthesia, compared to the delayed onset
after intraoperative rectal administration.
More recently, an intravenous preparation of
paracetamol has become available, superseding
propacetamol, a prodrug that was associated
with pain on injection [111]. Compared with
its oral administration following surgery, plasma
concentrations are higher and less variable in
adults [73]. A recent case report was published
following the safe and successful use of intravenous
paracetamol in a neonate.
1
Tramadol
Tramadol can be administered orally or
intravenously using intermittent bolus dosing or
a patient-controlled analgesia (PCA) device in
children. Its principle advantages over opioids are
a lower incidence of constipation and respiratory
depression with theoretical advantages in children
with obstructive sleep apnoea [75] and children
with disabilities who are prone to constipation. It
provides analgesia similar to morphine in children
undergoing tonsillectomy [51, 75]. It may, however,
lower the seizure threshold and is contraindicated
in children with epilepsy and those receiving
antidepressant medication.
Tramadol has also been administered rectally in
children. One small study demonstrated little inter-
individual variation in pharmacokinetic parameters
in children aged 1 to 6 years [187].
Tramadol clearance increases rapidly from 25 weeks
postconception age (5.52 l.h
-1
per 70 kg) to reach
84% of the mature value by 44 weeks [3]. Tramadol
is primarily metabolised into O–desmethyl tramadol
(M1) by CYP2D6. e active M1 metabolite
mediates tramadol’s mu-receptor agonist effect.
Poor metabolisers exhibit reduced analgesia [52]
and less nausea [125]. It is important to realise
that poor metabolisers may still attain significant
analgesia from its other mechanisms of analgesic
action, increased serotonin release and reduced
serotonin and noradrenaline reuptake [52].
Ketamine
Recently, it has been suggested that ketamine even
in sub-hypnotic doses may induce cortical neuronal
apoptosis [185]. is concern has emerged as
ketamine’s analgesic properties have been subjected
to more rigorous study to investigate its potential
opioid-sparing effect and has led many anaesthetists
to becoming reluctant to using ketamine in children
less than 2 years of age.
Racemic ketamine infusion at low dose (0.1–0.4 mg/
kg/h) is used to improve analgesia that is inadequate
after opioid infusion dosage is optimised. Reaching
an accepted maximal opioid infusion rate triggers
ketamine prescription, facilitating nursing care
on a regular ward rather than worrying about the
respiratory depressant potential as opioid dosage is
increased. Where moderate to severe pain can be
expected, ketamine infusion is often used as an
adjunct to opioid analgesia.
Opioids
Opioid analgesia is effective for moderate to
severe pain and titrated to response. Safe doses
for intravenous and epidural administration have
been established (Table 19.01). Paramount to their
safe use is the establishment of hospital guidelines
regarding their prescription and the level of nursing
care required. Sample charts and guidelines can
be viewed on this website: www.rch.org.au/anaes/
pain.
Intravenous PCA is suitable for most children over
7 years of age. Some younger children may also be
able to understand the concept of self-administering
analgesia.
Neonates are more susceptible to the respiratory
depressant effects of opioids, especially those
born prematurely. Opioids can be used provided
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316 George CHALKIADIS
appropriate monitoring is available. Most surgery
performed in the neonatal period is sub-umbilical
and amenable to regional techniques or major
cardiac, thoracic or abdominal surgery that would
require intensive care monitoring anyway.
Morphine 3-glucoronide is the predominant
morphine metabolite in infants and total body
clearance is 80% that of adult values by 6 months of
age. Metabolite formation decreases with increased
serum bilirubin concentration [25].
Oral opioid analgesia is used as step-down analgesia
as opioid requirements decrease. For patients
expected to have ongoing moderate pain such as
adolescents undergoing scoliosis correction, the
oral dose can usually be commenced after 72 hours
and calculated from their intravenous PCA usage
over the last 24 hours. Oxycodone, morphine or
codeine may be used.
Oxycodone and morphine may be preferable to
codeine. e cytochrome P450 enzyme CYP2D6
exhibits significant genetic variation in activity.
After codeine administration, neither morphine
nor its metabolites were detectable in 36% of
British children, implying no analgesic benefit.
Moreover there was a significant relationship
between phenotype and plasma morphine [174].
ere is considerable ethnic variation, with 1%
of Arabs and 30% of Hong Kong Chinese being
poor metabolisers. On the other hand, ultra-rapid
metabolisers may develop increased side effects of
codeine, and may require lower doses to achieve
the required therapeutic effect [173].
ere is, however, debate whether codeine’s
analgesic properties are due to conversion to
morphine by CYP2D6 [13]. Another metabolite,
codeine-6-glucuronide, may be responsible.
Another interesting observation is that in the
Oxford League Table of Analgesic Efficacy which
ranks analgesics in order of the number needed to
treat (NNT) to produce 50% reduction in pain for
4 to 6 hours in patients with moderate to severe
pain, codeine 60 mg alone ranks last with a NNT
of 17. Paracetamol 1 g alone has a NNT of 4.6,
whereas the combination of the two reduces the
NNT to 1.9 [105].
Remifentanil possesses the advantage of a short
context-sensitive half-life (3–5 min) attributable
to its biotransformation by non-specific tissue
and plasma esterases. Its rapid onset of action
and elimination make it ideal for use in the
operating theatre and possibly for brief, noxious
painful procedures in neonates and children in the
intensive care unit [2, 121]. In contrast, the large
variability in the dose of remifentanil tolerated
under anaesthesia make it unsuitable for children
breathing spontaneously [9].
Transdermal fentanyl patches are effective for the
management of cancer related pain [37]. A reservoir
of drug that crosses through a semipermeable
membrane allows for a constant rate of absorption
across the skin. A newer transdermal patch
preparation (2.1 mg per patch) delivering 12 mcg/
hour is available for paediatric use.
Transmucosal fentanyl is presented in a form
resembling a lollipop. It is rapidly absorbed into
the systemic circulation across the buccal mucosa
(within 10–20 minutes). It has been administered
as premedication [74] and prior to painful
procedures such as burns dressings [130], lumbar
puncture and bone marrow aspiration [136] and
provides analgesia within 20 minutes that lasts
up to 2 hours. Vomiting is a common side effect
especially in opioid naive patients. More recently,
an effervescent buccal tablet has been developed
but there are no reports regarding its use in children
as yet [40].
Morphine 20 mcg/kg administered intrathecally,
has been demonstrated to provide a significant
intravenous morphine-sparing effect in children
undergoing cardiac surgery [149]. However, its
use did not result in earlier extubation or earlier
discharge from the intensive care unit.
Clonidine
e caudal epidural administration of clonidine
prolongs the duration of local anaesthetic block
[159]. e degree of prolongation may be dose-
dependant. Higher clonidine (5 mcg/kg) doses
result in more hypotension and sedation [110].
In children with cerebral palsy undergoing
multilevel surgery, children receiving epidural
clonidine vomit less and receive less boluses of
epidural solution postoperatively, when clonidine
or feutanyl are added to bupiracaine 0.125% and
administered by infusion. ere is a small group
of patients who become profoundly hypotensive.
is tends to occur around 60 to 90 minutes after
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Pain in Children and Adolescents 317
the epidural administration of clonidine 2 mcg/
kg and is unresponsive to fluids. In this situation,
clonidine should not be used by infusion
postoperatively.
Oral clonidine (up to 5 mcg/kg tds) has proved
useful in patients discharged from the intensive
care unit having recently received high-dose
opioids. Withdrawal symptoms are avoided and,
anecdotally, children are less agitated and exhibit
less sleep disturbance [5].
Transdermal clonidine is available in some
countries.
Non-steroidal anti-inammatory drugs
Non-steroidal anti-inflammatory drugs (NSAIDs)
are effective for mild to moderate pain. eir
use in children is well established. ey can
be administered orally, rectally, topically and
intravenously. For oral administration, syrup and
tablets are available.
Clearance data for NSAIDs in neonates and
infants suggests that clearance increases with age.
Ibuprofen clearance increases from 2.06 ml.h
-1
.kg
-1
at 22 to 31 weeks postconception age [12], to 9.49
ml.h
-1
.kg
-1
at 28 weeks postconception age [165]
and to 140 ml.h
-1
.kg
-1
at 5 years [138].
Attention to adequate hydration in the perioperative
period is important when NSAIDs are prescribed.
Several cases of acute renal failure after perioperative
ketorolac administration have been reported [29].
Lower ketorolac doses are now recommended (0.2
mg/kg up to a maximum dose of 10 mg).
ere is considerable controversy regarding the risk
of bleeding with the use of non-selective NSAIDs
for analgesia after tonsillectomy. Ketorolac has
been reported to be associated with increased risk
of intraoperative and postoperative bleeding after
paediatric tonsillectomy [133, 143], but both studies
used a high dose (1 mg/kg). e topic has been the
subject of a Cochrane database systematic review,
which concluded that NSAIDs did not cause any
increase in bleeding requiring a return to theatre, and
that their use was associated with less postoperative
nausea and vomiting [31]. No published data exist
regarding the use of parecoxib, a selective COX-2
inhibitor. e addition of ibuprofen to paracetamol
was found to provide better analgesia than the
addition of rofecoxib [124].
Controversy also exists regarding NSAIDs’
potential for contributing to delayed bone union,
non-union or bone graft failure in orthopaedic
surgery. erapeutically, NSAIDs are used to
prevent heterotopic bone formation adding some
weight to the concerns of orthopaedic surgeons
[57]. e short-term use of NSAIDs up to 72 hours
is, however, accepted by some surgeons.
1. Contraindications
Aspirin should not be administered to children
because of the risk of Reye’s syndrome [66].
Non-steroidal anti-inflammatory drugs should
not be administered to children with the triad
of asthma, nasal polyps and aspirin sensitivity
(urticaria and angioedema). Also, NSAIDs may
precipitate bronchospasm in susceptible individuals
and are best avoided in children with moderate to
severe asthma.
All NSAIDs are best taken with food to avoid
gastrointestinal side effects. ey are relatively
contraindicated in children who are fasting
or very unwell and also in children receiving
chemotherapy.
Amide local anaesthetics
Excessive dosing underpinned several reports of
central nervous system (CNS) toxicity in infants
during continuous racemic bupivacaine infusions
in the mid-1990s [22]. No data on bupivacaine
clearance were available. Subsequently, with the
development of the newer amide local anaesthetics
levobupivacaine and ropivacaine, pharmacokinetic
studies have demonstrated reduced clearance in the
very young.
Levobupivacaine’s clearance increases from 5.8
l.h
-1
per 70 kg at 1 month to reach 80% of the
mature value (22.1 l.h
-1
per 70 kg) by 6 months’
postnatal age [34]. e P450 enzymes, CYP1A2
and CYP3A4, which metabolise ropivacaine and
levobupivacaine, mature at different rates, with
the latter’s activity appearing in the first week,
whereas CYP1A2 appears later. Ropivacaine data
on age-related unbound clearance are consistent
showing that maturation is reached by 6 months
of age [24]. Although unbound plasma ropivacaine
concentrations were higher in neonates suggesting
a need for caution, levels did not change with the
duration of infusion and remained less than the
threshold for CNS toxicity in adults.
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318 George CHALKIADIS
Regional blocks and use of local
anaesthetics for acute pain
Many minor surgical procedures which children
undergo are amenable to simple nerve blocks with
local anaesthetics. ese are commonly performed
after the induction of anaesthesia and prior to the
commencement of surgery, obviating the need
to administer opioid analgesia intraoperatively
which may result in postoperative nausea and
vomiting and offering the advantage of prolonged
postoperative analgesia. It is important not to use
solutions containing adrenaline where end artery
supply may be compromised such as the digits,
penis, ear and nose. Table 19.02 lists the indications
for commonly performed blocks.
Ultrasound
ere is an emerging literature on the use of
ultrasound to facilitate successful nerve blockade.
Ultrasound guidance allows the anaesthetist to
visualise the position of the needle tip relative to
the nerve [98]. More accurate needle placement
may result in higher success rates [178], improved
quality of block with shorter onset time and
extended duration [99], reduction in the volume
of local anaesthetic required [175] and fewer
complications. Ultrasound guidance has been
used to perform infraclavicular brachial plexus
[99], ilioinguinal/iliohypogastric nerve [175],
rectus sheath [176] and lumbar plexus [87] blocks.
In neonates, ultrasonography allows visualisation
of the ligamentum flavum, dura mater and the
termination of the spinal cord as well as the spread
of local anaesthetic solution within the epidural
space [177]. e visibility of the dura decreases
with increasing age and weight. In one study, it
was most reliably seen in infants less than 5 kg
in weight [97], although others have reported
“good” visualisation in children up to 7 years of
age [85].
Electrical stimulation
Electrical stimulation (1-10 mA) with a segmental
motor response can be used to guide the
advancement of epidural catheters inserted into the
caudal epidural space to the desired height [162]. In
this technique, an adapter is attached to the epidural
catheter, and both primed with saline. A nerve
stimulator is then used at 1 Hz to detect truncal
or limb movement. e motor response to low
milliamperage (<1 mA) may indicate subarachnoid
placement if bilateral [16] or subdural placement if
diffuse and bilateral [159]. Failure to obliterate the
motor response by administering local anaesthetic
may indicate intravascular placement [160]. A
nerve stimulator is also useful when performing
brachial plexus, sciatic and femoral nerve blocks.
Electrocardiography has also been used to confirm
epidural catheter tip placement in children where a
thoracic location was desired after caudal insertion
[161].
Performing blocks without guidance
It is important to remember though that for
many years, peripheral nerve blocks have been
safely and successfully used in children, relying
upon the anaesthetist’s anatomical knowledge
and technical skill. Many children live in lesser
developed countries where access to expensive new
technologies is limited. Lack of access to these
should not preclude children from receiving and
benefiting from peripheral nerve blocks.
Commonly performed blocks
Some of the simpler and most frequently employed
blocks in children are described below.
Ilioinguinal nerve block
A short bevelled needle is inserted through the
skin 1–2 cm medial to the anterior superior iliac
spine, depending on the child’s size. A two “pop”
technique is used. e first “pop” occurs as the
needle penetrates the external oblique aponeurosis.
Local anaesthetic 1–2 ml (0.25% plain bupivacaine)
bathes the ilioinguinal and iliohypogastric nerves at
this point. Advancing the needle further, a second
“pop” is felt as the needle penetrates the internal
oblique muscle. A further 1–2 ml of local anaesthetic
agent is injected, and tracks medially to surround
the inguinal canal. As the needle is withdrawn, it is
redirected subcutaneously along the line of surgical
incision and a further 1 ml of local anaesthetic
is injected as the needle is withdrawn to provide
anaesthesia of the skin. Plain local anaesthetic is
used because the testicular arterial supply is located
in the inguinal canal, and may be compromised if
adrenaline is used.
e “pops” are associated with a loss of resistance.
Encountering any resistance in injection suggests
that the needle tip is incorrectly situated within
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Pain in Children and Adolescents 319
either the external or internal oblique muscles.
Inadvertent femoral nerve block and colonic
puncture leading to subserosal haematoma have
been reported following attempts to perform
ilioinguinal nerve block in children [61, 80].
Penile block
e dorsal nerves of the penis are located next to
the arteries and veins that supply the penis, in the
Figure 19.01 Cross-section through x–x in Fig. 2 showing the membranous layer of the superficial fascia
dividing to form the suspensory ligament of the penis. This divides to encircle the shaft of the penis. The nerves
and vessels lie deep to the divided ligament. The needles show the bilateral approach for penile block that
avoids vessel damage and potential haematoma.
(This Figure was originally published in Anaesthesia for Children, 2nd edn. Blackwell Scientific Publications, Oxford 1992,
edited by TCK Brown and GC Fisk. Permission to use in this Chapter is granted from Blackwell Scientific Publications.)
triangular space formed by the suspensory ligament
that divides into two sheets which pass around the
shaft of the penis (Fig. 19.01). Injecting here may
cause a haematoma. e suspensory ligament forms
two potential spaces either side of it, superior to
the neurovascular bundle. Viewed laterally, another
triangular compartment is formed by the symphysis
pubis above, the corpora cavernosa below and a
membranous layer of fascia anteriorly (Fig. 19.02).
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