View
137
Download
7
Category
Preview:
Citation preview
1
THE COMPARISONS OF POPLITEAL BLOCK
VERSUS ANKLE BLOCK ANAESTHESIA FOR
FOOT SURGERY
SIAN FLEMING Candidate number: 20076382
Word Count – 9, 113
University College Northampton Submitted – May 2004
2
Abstract
This study examines the current knowledge and research of popliteal and ankle nerve block
anaesthesia.
Multiple forefoot procedures may require increased tourniquet time and can benefit from
prolonged post-operative anaesthesia. Thus popliteal blocks have a role to play in such cases.
This extended literature review will evaluate and compare the risks and benefits of popliteal
block versus ankle block anaesthesia.
The overall conclusion was that ankle block anaesthesia, especially with the use of sedation
enables a fast onset, good intra and post operative analgesia for foot and ankle surgery. It is
an ‘easy to administer’ block compared to other peripheral nerve blocks e.g. popliteal blocks
and does not require specialist equipment or anaesthetist.
There does appear to be a lack of statistics relating to the advantage and or disadvantage of
popliteal block and ankle block anaesthesia and further quantitative studies need to be
completed to confirm these suggestions.
3
Acknowledgements
I would like to thank and acknowledge the following people:
• Paul Besson – dissertation supervisor. Your advice and guidance have proven invaluable. • My Mum and Dad. I will never forget your help and support throughout the stressful
times, thank you. • Ian Thomasson. Thank you for your constant reassurance and patience. • All my friends, old and new you know who you are, for always being there when I
needed you.
4
CONTENTS Abstract 2 Acknowledgements 3 Contents 4 Chapters
1. Introduction
Aims and Objectives 5 Anatomy 7 Local anaesthetics 13
2. Literature Review
Selective blocking 15 Mixing local anaesthetics and additives 19 Electronic nerve stimulators 21 Tourniquets for foot surgery 23 Types of anaesthetic 25 Post operative pain relief 26 General or regional anaesthesia 28 Patient management following surgery with peripheral nerve blockade 31 Psycho-social aspects of anaesthesia 31 Critical Analysis of Previous Papers 33
3. Results
Popliteal block 37 Ankle block 39 Visual analogue scale 40
4. Conclusion 42 Appendix A 45 Appendix B 46 References 47 Bibliography 50
5
Introduction
Chapter One: Aims and Objectives
The aims of this study are to
1. Identify the main risks and disadvantages of both popliteal block and ankle block
anaesthesia
2. Compare these to the benefits of both.
Objectives:
1. Comparing the results from previous studies.
2. Examining the weaknesses of previous studies
3. Finding areas of improvement in previous studies
4. Comparing the contra-indications of both blocks.
Comparing two types of Local anaesthetic techniques will provide podiatric surgery the
information required to ensure the correct block is being used (individuality must be
considered for each patient). This should give surgeons the confidence to use one particular
technique over the other.
This study will be undertaken a detailed and extended literature review. Thus there was no
need for ethical committee approval.
6
Search Strategy
All data for this study has been collected using previous work, using already published
studies, articles, journals, books, previous dissertations and personal communication.
The library at the University College Northampton, The Cripps Library (Northampton
General Hospital) and The British Library were the areas in which the material for this study
was collected with the use of databases such as: AHMED
Medline
Cochrane
Science Direct
Embase
Zetoc
Athens
And using various academic websites e.g. Pubmed, Ovid citations.
Anatomy
Blood Supply
7
The popliteal fossa is a diamond shaped cavity on the posterior aspect of the knee joint. It is
bound inferiorly by the lateral and medial heads of gastrocnemius, superiorly laterally by the
long head of biceps femoris and medially by semitendinosis and semi membranosis tendons.
The floor consists of the femur, tibia and ligaments of the knee. The popliteal artery is the
deepest of the structures within the popliteal fossa and ends by dividing into the anterior and
posterior tibial arteries. With the knee flexed the popliteal pulse can be felt. The popliteal
vein is formed at the lower border of the popliteus by the anterior and posterior tibial veins. It
is bound by dense fascial sheath and crosses behind the artery medial to lateral as it ascends.
Both the popliteal vein and artery are protected by a considerable amount of fat and areolar
connective tissue.
All of the muscles, vessels and nerves entering the foot do so by crossing the ankle joint.
Deep to and behind the middle compartment of the extensor retinaculum passes the anterior
tibial artery, which at the inferior border of the retinaculum and deep to the peroneal nerve
becomes the dorsalis pedis artery. The posterior tibial artery together with the tibial nerve are
located behind the medial malleolus which then divide into their terminal medial and lateral
plantar branches.
Nerve Supply
8
The sciatic nerve innovates the posterior knee and lower leg and can be found at the proximal
margin of the popliteal fossa. This subsequently divides into the tibial nerve and the common
peroneal nerve laterally. It then winds around the fibular neck and into the anterior
compartment of the leg. The tibial nerve continues in the midline axis below the popliteal
fascia, between the femoral condyles and into the deep posterior compartment of the leg.
The saphenous nerve is the largest cutaneous branch of the femoral nerve, descends on the
lateral aspect of the femoral artery and enters the adductor cannal. Here it crosses in front of
the artery obliquely from its lateral to medial side. It diverges from the artery at the lower end
of the cannal and emerges through
the aponeurotic covering. It continues distally along the medial aspect of the knee with the
great saphenous vein and terminates along the medial aspect of the ankle and foot. The
superficial peroneal nerve perforates the crural fascia on the anterior aspect of the distal two
thirds of the leg and continues along the lateral border of the ankle and leg subcutaneously.
The deep peroneal nerve is situated in the dorsum of the foot, between the first and second
toes deep and between to the extensor tendons. The dorsalis pedis provides a good landmark
for identification of this nerve as it lies just lateral to it. The sural nerve arises as a
coalescence of the tibial nerve and the common peroneal nerve and at the distal midpoint of
the leg becomes subcutaneous. Along with the short saphenous vein it passes inferiorly and
posterior to the lateral malleolus.
Innervation occurs as follows:
The Saphenous nerve innervates the medial ankle.
9
The Superficial peroneal nerve innervates the dorsal of all the toes.
The Deep peroneal nerve innervates the interdigital space between the first and second toes.
The sural nerve innervates the heel area and the lateral part of the foot.
The Posterior tibial nerve innervates the sole of the foot.
The Popliteal Nerve Block
A popliteal block can be achieved by using one of two methods. The posterior and lateral
approach. Which technique is used is dependant on the procedure and whether the regional
block is being solely used for anaesthesia or in combination with general anaesthesia. If a
popliteal block is performed after induction of general anaesthetic then it is considered that
the posterior approach is more inconvenient as the patient has to lie prone. Tagoe et al 1998
state that contra indications of this approach prevent it being safely achieved in patients with
severe limb pain unstable cervical spine injuries, haemodynamic instability or advanced
pregnancy. However, these are unlikely to be an issue in elective podiatric surgery and the
same study claimed that it authors’ found the posterior approach to be easier.
This approach can be achieved by laying the patient prone with the leg flexed. This provides
good definition of the popliteal fossa.
10
When utilising an ankle block five nerves need to be blocked; the posterior tibial, superficial
peroneal, deep peroneal, sural and saphenous. As four of the nerves are almost entirely
sensory an infiltration technique should be used and all five nerves are blocked by an
infiltration ring of local anaesthetic around the ankle.
Ankle Nerve block
The Saphenous Nerve, Superficial and Deep Peroneal Nerve Block
These three nerves can be blocked from a single injection site. The needle is inserted between
the tendons of extensor digitorum and extensor hallucis longus, at the level of the malleoli.
When the tibia is reached by the needle it is then withdrawn with aspiration by 1 to 2 mm.
The La is then injected to block the deep peroneal nerve. To anaethnatise the superficial
peroneal nerve the needle can be withdrawn from the current position so the needle remains
in the skin. The needle needs to be turned towards the lateral malleolus and 5ml of local
anaesthetic should be injected in a subcutaneous band between the lateral malleolus and the
anterior border of the tibia, enabling all branches of the nerve to be reached.
Finally withdraw the needle again to just below the skin surface and turn the needle to face
toward the medial malleolus. 5ml of local anaesthetic needs to be injected whilst the needle
advances toward the medial malleolus. To ensure complete analgesia of this nerve the nerve
may require further local anaesthesia which can be injected via a separate puncture wound
lateral to the great saphenous vein. This lies antero-medial to the medial malleolus and by
using a separate puncture site damage to the vein is be reduced.
11
The Sural Nerve Block
The sural nerve can be found at the upper end of the lateral malleolus lateral to the achillies
tendon and is a coalescence of the common peroneal nerve and the tibial nerve. To ensure
injection is in close proximity to the nerve it is often helpful to ask the patient to tell the
anaesthetist when parasthesia is elicited.
The Posterior Tibial Nerve Block
It may be necessary to locate and mark the posterior tibial artery using a Doppler and a
marker pen to prevent any damage to the artery during injection. Stimulation of the nerve can
be achieved using a electronic nerve stimulator, Reilley et al (2002) recommend the use of a
24-gauge 25-ml Stimuplex needle. This is inserted into the skin at the level of the superior
border of the mallelous just behind the previously marked artery the needle will be advanced
until plantarflexion of the toes (particularly the first) occurs with less than 0.5 mA of current
(Reilley et al (2002)). Here, 0.5mL of local anaesthetic should be injected. A successful
blockade will be identified by the immediate halt of toe flexion.
If a nerve stimulator is not accessible, then by using a fan-like movement of the needle,
although this does not always produce a successful block.
It can be painful to the patient when administering any type of injectable local anaesthesia, in
view of this a good technique is important to help reduce any discomfort. This can be
achieved by warming to local anaesthetic to body temperature before injection and injecting
slowly. Sedation may be required to ease the pain caused. (McCormick 1999)
13
Local anaesthetics work by reversibly decreasing the rate and degree of nerve membrane
depolarisation. This is done by blocking the sodium channel or combining with specific
receptor s within the channel so there is prevention of sodium flux across the membrane.
Thus the threshold potential for transmission is not achieved and the electrical impulse is not
propagated down the nerve. All this prevents sodium ion flux across the membrane. There is
no change in the threshold or resting potential, however, the refractory period and
repolarisation may be prolonged. (Tuckley 1994).
The majority of local anaesthetic agents are tertiary amine bases which are administered as
water soluble hydrochlorides. The relatively alkaline pH of tissue fluids aids the liberation of
the amine base after injection that after injection. The pH of the solution and the pKa of the
drug will then determine the proportions of the local anaesthetic in both ionised and non-
ionised forms. It is the ionised form that enters the sodium channel and blocks the channel or
combines with a specific receptor within the channel resulting in channel blockade.
The larger the diameter of the nerve fibre the greater the concentration of local anaesthetic
required to produce channel blockade. A larger dose of local anaesthetic may be indicated if
the injection site is affected with infection or ischemia. As this will decrease extraneuronal
local pH and it is only the unionised portion that diffuses through the neuronal membrane.
This converts more molecules of the drug to the ionised form which in turn decreases the
diffusion of drug into the nerve. It is important to refer back to and be aware of the
maximum safe dosage if the local anaesthetic seems to have little effect in these cases to
prevent injecting too high a dose. As pain is the first sensation to be lost after a local
anaesthetic injection pressure and light touch are still detectable by the patient and must be
remembered when testing for anaesthesia.
14
When using local anaesthetic the goals remain the same with which ever technique is
performed. These are to:
• Provide pain relief.
• Maintain intraoperative homeostasis.
• Provide good surgical access
• Ensuring rapid and safe recovery of patient.
Chapter Two: Literature Review
Selective blocking
Many find it an advantage to selectively block (posterior tibial, deep peroneal and superficial
peroneal nerves) the nerves when performing an ankle block for fore foot surgery rather than
a complete block (same as for selective blocking plus sural nerve and saphenous nerve).
However, it has been proved that the pain experienced by the tourniquet when only a
15
selective block is achieved far out way's the benefits. It may appear that a selective block
would decrease the amount of local anaesthetic in the body systems and so therefore reducing
the risks associated. Some may ague that anaesthetising the whole foot when surgery is only
to be performed on one area appears a waste of time and waste of materials. However,
Delgado-Martinez (2001) found that supplementary local anaesthetic was required in 52% of
cases compared to only 11% who had a complete block. This study concludes that there are
similar complication rates between selective and complete blocking and therefore
recommends complete ankle block technique. The authors of a study by Wooden et al (1990)
selectively blocked the nerves with success whilst performing an ankle block with respect to
individual procedures. Mcleod at al (1995) found selective blocking also to be a success.
They claimed that they did not block the sural nerve in any (19 out of 40) patients as no
surgery was performed involving the lateral aspect of the foot. There was no significant
difference in patient satisfaction by using selective ankle blocks compared to popliteal blocks
in this study.
Both ankle block and popliteal block anaesthesia allow surgery to be undertaken to all areas
of the foot. Both provide post-operative pain relief and allow surgery to be completed as day
cases. Rongstad et al (1996) found that with the use of popliteal nerve block provided 20
hours of pain relief, whereas Mcleod at al (1995) found that the ankle block technique only
provided 11.5 hours on average of pain relief but did show that this was more reliably
performed.
Regional anaesthesia has many benefits over general anaesthesia, of which, post operative
pain, lack of post operative nausea, complete reversibility of action and low systemic toxicity
16
are the most significant. The use of regional anaesthesia also reduces the need for extensive
post operative care therefore reducing the expense for hospital and patient. However as
confirmed by Reilley et al (2002) regional anaesthetic techniques have a higher chance for
success in the foot and ankle than in any other site of the human body. It is therefore seen as
beneficial to avoid general anaesthesia in those who may be at a higher risk of complication
e.g. in those who are obese, elderly, have problematic airways, cardiac and pulmonary
compromise, diabetes or sleep apnea. However, local anaesthesia carries its own risks, even
though not as common or necessarily as severe as general anaesthesia they must be
recognised and addressed. Kelly et al (2000) discusses that the main problem with regional
anaesthesia is patient non-acceptance
With both, but a higher chance with ankle block as more injection sites, there is risk of
systemic or localised infection at the site of injection. As with all local anaesthetic techniques
there is a danger of intra-vascular injection (meticulous aspiration make is unlikely), toxicity,
hypersensitivity and neuropraxia although these are rare (Wallace 1991). The chance of
toxicity and hypersensitivity can be reduced by not using lignocaine, as this is associated
with higher risk of adverse reaction. However, a decrease in cardiac output and hypotension
has be associated with the use of Bupivacaine in particular. In addition Prilocaine has been
linked to methaemoglobinemia causing irregularities in respiratory drive, cyanosis and
greying of the skin, all as a result of its metabolite acting as an oxidising agent of
haemoglobin.
By not using vaso-constrictor agents with the local anaesthetic, the danger of a toxic reaction
is reduced. Using amide-derived anaesthetics also lowers the chance of a toxic reaction. This
is due to their lack of para-aminobenzoic acid compared to the ester derivatives. If any
hypersensitivity is noticed the injection must be terminated and vital signs should be checked.
17
Basic life support protocols should be implemented and intravenous fluids, vasopressors and
antiarrhythmic drugs should be employed if hypotension or dysrhythmias occur.
Anticonvulsant drugs such as Diazepam and thiopentone can help reduce fitting if required.
Kelly et al (2000) found that out of 86 patients that had foot surgery with the ankle block
local anaesthetic technique “there were no cases of systemic local anaesthetic toxicity and no
complications related to inability to heel pain during the early post-operative period”.
There is an increased risk of nerve damage when giving a popliteal nerve block because the
relatively high amounts of adipose tissue in this area impairs the diffusion of local
anaesthetic. Due to this administration of the drug must be as close to the nerve as possible to
ensure its effectiveness. However, the use of a nerve stimulator could over come this
potential problem.
Wallace (1991) discusses that syncope is the most common complication following local
anaesthetic injection. This presents as a 'light-headed' feeling, clammy skin and the patient
may warn staff that they may faint. Talking to the patient whilst injecting can help to alert the
anaesthetist of any confusion which could suggest possible toxicity.
All risks associated with injecting local anaesthetics can be reduced by abiding to three main
rules, (1) ensure concentration of LA is not higher than required, (2) not injecting excessive
amounts of LA, (3) ensure there is no contamination of anaesthetic by either the
manufacturer variants or contaminants when using multiple vials for drawing up the drugs.
The study by Wallace (1991) also states that local anaesthetics are only directly related to 1%
of allergic reactions.
Patients who have undergone Modified anaesthesia care (MAC) postoperatively must be
monitored for nausea, pain and cardiorespiratory function. Recuperation speed depends on
level and type of sedation and length of procedure. Patient's metabolism and drug interactions
18
may also play a part in recovery time. A study by Mercandetti et al (2002) suggests that
general anaesthesia is still preferred to MAC for lengthy or complex surgery. As general
anaesthesia provides security in airway, amnesia, analgesia and muscle relaxant.
Mixing Local Anaesthetics
Mixing local anaesthetics can increase the advantages of the drugs, e.g. by mixing Lidocaine
with bupivacaine, a rapid onset local anaesthetic with a long duration is achieved. It must be
remembered that only half the concentration of each can be administered however, this may
lead to insufficient anaesthetic density for the surgical procedure. In a study by Reilley et al
(2002) it was found by the authors that a better peripheral nerve block could be achieved by
using adequate concentrations of a single agent. The onset time for the blocks to be fully
achieved can be decreased by adding NaHCO3.HO.
19
Additives
Most local anaesthetics (cocaine being an exception) cause vasodilation. Cocaine is the only
local anaesthetic that causes vasoconstriction consistently as it is able to inhibit the re-uptake
of nor-epinephrine by storage granules at the synapse. This causes an excess in concentration
of free circulating nor-epinephrine which results in vasoconstriction. The addition of a
vasoconstrictor particularly epinephrine helps to decrease local blood flow. The local
anaesthetic can be confined to the administration site as the vasoconstrictor acts as a
'chemical tourniquet'. It also slows the rate of absorption of the local anaesthetic, prolongs its
local effect and reduces the chance for systemic toxicity (Tuckley 1994).
A study by Wallace (1991) stated that epinephrine in concentrations of 1:100,000 and
1:200,000 can depress the local absorption of the anaesthetic. A smaller volume is required
yet still providing prolonged duration. Some local anaesthetics are manufactured, prepared
with epinephrine i.e. lidocaine. The pH is adjusted to a higher acidity range during
preparation of such solutions to prevent degradation of the epinephrine.
As the majority of the local anaesthetic remains in the ionised form these solutions have a
very slow set-up time. Due to this, Reilley at al (2002) believed these local anaesthetics are
unsuitable for peripheral nerve blocks.
20
The degree of reduction of the peak concentration in blood depends in the site of injection
and the specific local anaesthetic agent, therefore solutions containing epinephrine must not
be used for infiltration around areas with a terminal vascular supply i.e. toes. The intensity of
the vasoconstriction may lead to severe ischaemia and necrosis.
Contra-indications for the use of epinephrine must be recorded before administration to avoid
any potential toxic reaction. If epinephrine is required it must be mixed with the local
anaesthetic freshly and used within 30 minutes. Although the addition of epinephrine enables
the maximum safe dosage of the local anaesthetic to be increased it must be noted that 10mL
of local anaesthetic with 50µL (0.05mL or 1:1000) epinephrine has a final concentration of
5µcg/ml (1:200,000). There is no justification for using a higher concentration.
The addition of alpha2-adrenergic agonists (i.e. clonidine, 10µg/ml) to lidocaine prolongs the
duration of peripheral nerve blocks, time to first analgesic request, total oral analgesic
required, and pain levels compared to administration of plain lidocaine postoperatively.
Clonidine is a sedative that has frequent amnesial effects and can be taken orally (3-5 µg/kg)
one hour before block placement and will have similar effects as if injected with the local
anaesthetic.
The sedation effect occurs due to the stimulation of a specific aplpha2 adrenergic receptors
together with a G protein, which results in cell membrane hyperpolarisation. Alpha2-
adrenergic agonists sedative effect is antagonised by alpha1 adrenergic agonists which
explains why less selective agents, for example clonidine, which has some alpha1 stimulatory
activity, do not achieve complete anaesthesia. They can reduced the MAC of co-administered
volatile anaesthetic agents and can reduce the dose of intravenous hypnotic required for
anaesthetic induction. (Maze et al 1988).
21
Another alpha2-adrenergic agonist dexmedetomidine, this is more selective than clonidine
and has a marked anaesthetic sparing effect during surgery. Dexedetomidine has been newly
introduced however little has been established as to its exact role at the time and further
research is required before this becomes a common drug used within podiatric surgery.
(Bonnet et al 2000).
Electronic Nerve Stimulators
The administration of a popliteal requires the specialised equipment, the electronic nerve
stimulator. Their usage ensures clear identification of nerves with a motor component to
prevent damage to the nerves or vessels lying in close proximity. However, the eliciting of
parasthesia that they cause can be uncomfortable for un-anaesthetized patients can result in
an increase in incidence of neurological complications. Although they solve many problems
associated with correct location of local anaesthetic injection they are not helpful if the
patient has received muscle relaxants (commonly used within general anaesthesia). Muscle
stimulation can be misleading response to that of nerve stimulation and therefore care must
be taken to ensure the correct stimulation effect is preformed and response should be sought
in an area where direct local stimulation could not occur. It must be noted that patients with
diabetes mellitus, sepsis, hypothyroidism, hypothermia and old age may require an increase
for stimulating current during nerve localisation (Nysora.com). There are many different
types of nerve stimulators, however, the point of maximum current density remains in the
22
same area. This lies just in front of the tip of the needle and so nerve stimulation should occur
without actually touching the nerve. In view of this nerve damage should be a low risk. The
equipment needs to be used by a specialised operator/anaesthetist, to ensure safety in its use.
A low current should always be selected (0.5mA) or stimulation may occur some distance
from the nerve resulting in a incorrect positioning and subsequent poor nerve blockage. If a
successful block is completed the nerve contractions stop after the first 1-2ml of anaesthetic
(Reilley et al 2002). This mechanism may be due to physical deformation of the nerve fibres
by the small volume injected rather than due to a pharmacological action of the anaesthetic
(the same effect is noticed if saline is injected). There is no need for the use of the nerve
stimulator when utilising the ankle block technique this is because it is sufficient to deliver
the drug just beside the nerve. Previous authors have reported that variations in anatomy
despite careful injections can lead in incomplete anaesthesia (Lee et al 1996; Tagoe et al
1998). This could make the ankle block easier to administer as less time will be lost trying to
find parasthesia and there is no need for a specialised operator for the machinery.
Tourniquets for Foot Surgery
The popliteal block technique does allow a calf tourniquet to be used which extends the
scope of foot surgery possible. Provenzano et al (2002) say that ankle and rear foot
operations can be performed with the use of a calf tourniquet which would be unsuitable to
use if an ankle block was utilised due to the high level of pain experienced on its inflation.
23
The calf tourniquet allows more motion at the ankle and rearfoot which may aid some
operative procedures. It also ensures excellent vascular compression as a larger force can be
exerted by the tourniquet in this area as compared to an ankle tourniquet because there is a
higher volume of soft tissue in this area. Wooden et al (1990) found that by using a lubricant
on the skin and a cotton wrap under the tourniquet can help reduce the discomfort felt when
using only an ankle block for surgery. He also advised not to platarflex the foot when the
tourniquet is pressurised, as this may stretch and cause post operative pain. Rielley et al
(2002) suggest that if a thigh tourniquet is required for podiatric procedures then a lumbar
plexus nerve block is typically necessary to prevent tourniquet pain, however, very few
authors claim the use of a thigh tourniquet as necessary. This also increases the risks
associated with spinal anaesthesia when an ankle or calf cuff is sufficient.
In a study by Wallace et al 1991 it states that tourniquet pain after deflation may be
experienced as a result of local ischemia and anoxia produced directly underneath the
tourniquet not because of mechanical compression however, it is reversible. This study
shows hoe important post operative pain relief is.
Finsen et al (1997) found that under the use of an ankle block a 11cm wide calf tourniquet
inflated to 100mmHg above systolic blood pressure, was adequate to provide a successful
bloodless field and pain relief. In this study a visual analogue scale was used to identify the
level of pain present peri operatively and post operatively. The results showed that this calf
tourniquet gave significantly greater discomfort throughout the procedure and 10, 20 and 30
minutes afterwards than an ankle tourniquet. An ankle tourniquet of 9cm wide inflated to the
same amount provided less discomfort with no increase in nerve damage incidence.
24
Lee et al (1996) found that using sedation with an ankle block allows the unanesthetized
thigh tourniquet area to be tolerated. The same study shows that sedation was well endured in
98% of patients. However, Reilley et al (2002) clearly reports that a thigh tourniquet can only
be applied if general or spinal anaesthesia is used. Whereas a study carried out by Kelly et al
(2000) found that the use of a 15-cm wide low pressure ankle tourniquet inflated to
250mmHg was efficient for elective forefoot surgery. In the same study one patient out of a
hundred had conversion to general anaesthesia for tourniquet pain and tourniquet pressure
was reduced intraoperatively in four cases for patient comfort. Delgado-Martinez et al 2001
found in their study that 100% of patients undergoing fore foot surgery did not experience
any pain from an ankle tourniquet cuff during the procedure (tested using the visual analogue
scale without the use of a sedative).
The main reason for using intravenous sedation is to ensure the surgical procedure is a more
pleasant experience. It is often referred top as MAC (monitored anaesthesia care) and has
been proven to be safe and effective in foot and ankle surgery. A sedative agent (either a
narcotic, tranquilizer or hypnotic with or without nitrous oxide) can be added to the local
anaesthetic and injected at the required site. This will provide amnesia of the injection and
the surgical procedure. Contra-indications must be considered before injection of sedative
and must include a detailed medical and surgical history and physical examination. However,
the disadvantage to MAC is the lack of airway control and the threat of obstruction or
aspiration.
25
Type of Anaesthetic
As mentioned earlier a popliteal block provides a longer post-operative analgesia than ankle
block. This is due to the volume of anaesthetic used and the type of anaesthetic used.
Ropivacaine and bupivacaine will provide the longest post-operative analgesia. Using (0.5%)
of either of these agents allows 8-18 hours of analgesia after block placement. Reilley et al
(2002) reports that ropivacaine appears to have a greater sensory loss than motor blockade
compared to the same amount of bupivacaine. This means that motor function may return
while analgesia is maintained. Hansen et al (2000) used 40 ml of 2% mepivacaine and 0.25%
bupivacaine with 2mcg/ml of epinephrine and 0.2 ml of sodium bicarbonate solution for
popliteal blocks in his study.
McLeod et al 1995, used 20ml of 0.5%plain bupivacaine for both lateral popliteal sciatic
nerve blocks and ankle blocks following surgery under a standardised general anaesthetic.
The results show that the median duration of analgesia for the lateral popliteal sciatic nerve
block was 18 hours compared with only 11.5 hours for ankle block. The same study also
showed the increased need for morphine in the post anaesthetic recovery room (PAR) by
those patients who had the popliteal block. 43% of patients who had the popliteal block
requested morphine in the PAR as opposed to only 16% who had the ankle block. They
concluded that the increased pain experienced in PAR could be possibly due to a failure in
the saphenous nerve blocks. However, there was no difference in the patient satisfaction of
post operative analgesia between the two groups.
26
Post-Operative Pain Relief
Pain signals to the brain the presence of damage or disease within the body. Post operative
pain is a result of damage caused by surgery.
There are many methods of pain relief that can be used following podiatric surgery. These
include nonsteroidal anti-inflammatory drugs (NSAID's), oral and parenteral opioids, patient-
controlled analgesia and local anaesthesia injections (of which both the popliteal and ankle
block are common in foot and ankle procedure and can be used after surgery under general
anaesthesia). The contra-indication of these must be noted before suggesting which method is
suitable for each individual patient. A study by Charlton et al (1997) states that patients who
are afraid of anaesthesia or surgery report higher levels of pain post operatively and so
increases the difficulty in pain management. Detailed explanation of the surgical procedure
pre-operatively can reduce anxiety levels and ensure post operative pain levels are as low as
possible, this will benefit both the patient and the surgeon. Charlton (1997) suggests that due
to the multifactorial origin of pain, management should consist of a combination of
approaches to ensure the best results.
The side effects and risks of taking opioid drugs include, hypotension, respiratory depression,
vomiting, constipation and drowsiness. The side effects of NSAID's do not impair
respiration, gastro-intestinal modalities but can cause renal complications. Menicino et al
2002 suggest that by using a popliteal block for post operative pain relief the risk of side
effects from the above drugs is prevented and therefore patient satisfaction is increased.
However, if a popliteal block is to be administered it has been suggested that this must be
performed whilst the patient is awake and able to co-operate. This is because many
27
anaesthetists when performing a popliteal block ask the patient to make it clear to them when
parasthesia of the nerve is experienced. Provenzano et al (2002) state that this will aid the
prevention of intraneural injection. This view is confirmed by Choyce et al (2001) in which
they found parasthesia was experienced during popliteal injection by 23% of their patients
and finally, Morphett (2000) suggests that the risk of serious nerve damage is reduced if the
patient is conscious. This may give an advantage to using an ankle block as this can be
administered after surgery using general anaesthetic. No parasthesia is experienced when
giving an ankle block so patient compliance is not necessary and post operative pain relief is
still achieved.
It is thought that post operative pain may be preserved because hyperexcitable changes in
central neural function induced by the neural stimulus from any trauma, including surgical
incisions continues beyond the immediate poststimulation period. Therefore post operative
pain can be decreased beyond the local anaesthetic action time by preventing these changes
from occurring. This can be achieved by blocking the nociceptive input from entering the
central nervous system.
General or Regional Anaesthesia
Reilley et al 2002 claims that lack of training and expertise by many anaesthesiologists mean
they prefer to perform general anaesthetic rather than a satisfactory regional anaesthetic. This
study also states that newer regional anaesthesia techniques require training and specific
equipment. Many anaesthesiologists can in a correctly set up operating theatre put a patient
"to sleep" safely in 3-5 minutes.
28
Disagreeing with this view is a study by Kelly et al 2000 who found that in a survey of 3498
anaesthetists, 68% preferred to perform regional anaesthesia as opposed to general
anaesthesia. However, this study also suggests that patients would prefer to have a general an
anaesthetic, because they do not want to see or feel any thing during the surgery. It is
possible that patients are unaware of the advantages and disadvantages of both general and
regional anaesthesia before they make they make their choice of which to have during their
operation(s). Many patients suffering from podiatric pathology have predisposing conditions
of advanced age, diabetes, obesity or cardiac and pulmonary compromise. All of these factors
increase the risks associated with general anaesthesia. Lee et al (1996) found out of 355
patients who underwent surgery with regional anaesthesia 352 were successful and in the
same study from the 164 patients that responded to post operative surveys, 162 stated that if
necessary they would prefer to have surgery performed in the same way.
Elderly patients often benefit greatly from the use of regional anaesthesia, due to the higher
chance of associated medical conditions and smaller physiological reserves. Within this
group of patients the advantages of regional anaesthesia are the smaller drop in body
temperature intraoperatively, smaller blood loss and reduced incidence of ischemia.
However, due to the slower metabolism in the elderly and considering possible contra-
indications of medication and anaesthetic type the local anaesthetic may produce a more
profound effect. With this in mind peripheral nerve blocks e.g. popliteal or ankle block
anaesthesia would provide lower blood levels of anaesthetic and therefore reduce any adverse
reaction.
29
Diabetic patients also benefit from regional anaesthesia compared to general. Disturbance of
sugar levels increases with stress. There is less stress associated with regional anaesthesia
and a popliteal block would be the most advisable for patients in this group. Foot surgery for
patients with diabetes often involves vascular and infectious complications due to long term
imbalances in glucose metabolism. These patients can arrive for surgery with sepsis or
gangrene requiring immediate surgery. Due to this ankle nerve blockade would be un suitable
due to tissue acidosis and/or swelling in the ankle joint area. Often these patients also present
with significant coexisting diseases e.g. coronary artery disease and/or dehydration which
would present as a disadvantage to using neuroaxial anaesthesia. Therefore popliteal nerve
blockade appears to be the most valuable option, especially if the lateral approach to the
block is taken. This allows those that cannot lie prone to still receive a popliteal block.
However, it must be remembered that the duration of local anaesthetic in this group of
patients will be increased although there is no evidence that they are at a higher risk of
neurologic injury.
An advantage to using the ankle block technique for anaesthesia is that there is no loss of
motor function. This is because apart from the intrinsic muscles there is no motor supply to
the foot. Ambulation is primarily achieved through tendon and muscle movement of the leg
which continues down to the foot. When the foot is anaesthetised by using an ankle block the
intrinsic muscles do reduce the stability of the foot but it does not prevent ambulation.
However, the muscularskeletal system is affected when using the popliteal technique for
anaesthesia. Being unable to use the leg after the operation may increase postoperative risks
and further un-necessary damage e.g. falling over. Crutches would be necessary to aid
walking this can be achieved because there is no loss in ipsilateral hamstring function or
30
contralateral leg strength using this technique. Hansen et al (2000) stated that after foot
surgery with the use of popliteal block technique the patients were unable to weightbear for a
minimum of 12-18 hours to ensure neurological function had fully returned to the operated
foot. After this time weightbearing was evaluated dependant on individual operations.
Patient management following surgery with peripheral nerve blockade
The one main advantage of using a peripheral nerve block is that there is no need for
admission to post-anaesthesia care unit and the patient can be discharged straight onto a ward
or phase II recovery dependant on individual patients (Hansen et al 2000; Reilley et al 2002).
Assuming that no toxic reaction occurred as a result of the nerve blockade, similar steps are
taken as to the management of the patient following surgery. The wound should be dressed
and padded and patient advised not to attempt to move the extremity. Due to the loss in motor
function after popliteal blockade crutches will be required to aid mobilization, this may also
31
be indicated if a longer acting anaesthetic was used e.g. ropivacaine or bupivacaine (Tagoe et
al 1998). Advice on analgesic requirements must be given to the patient and are the same
following both popliteal and ankle block anaesthesia.
Psycho-Social Aspects of Anaesthesia
Pain management between children and adults differ due to the lack psychological
development of the child. Despair, distress and anger are classic symptoms shown by both
adults and children if they believe that no-one cares. Psychological techniques can be
performed to reassure the patient however they must be appropriate to the personality,
developmental stage and individual patient circumstances. Many patients respond well when
they are aware of the situation and what is going to 'happen' to them, however, some
especially adults may prefer not to know. Training the patient in breathing control, relaxation
techniques and autohyposis may aid to clam the patient and reduce anxiety levels (Thomas
1997). Distraction is a major technique used especially when the patient is under going
surgery with regional local anaesthetics. The patient is often advised to listen to music via a
personal stereo or a patient chaperone may assist in distraction by talking to the patient.
There has been suggestion that children who experience a significantly bad, painful
anaesthetic technique are more likely to be anxious in returning to the operating theatre in
future years. Pre-emptive analgesia has brought about some controversy, in this analgesia
should come before stimulus, even in an anaesthetised patient. Children are particularly
32
vulnerable to the psychological effects caused by waking from general anaesthesia in pain
(Mckenzie 1997). All this provides the conclusion that post operative analgesia via local
anaesthetic nerve blockade appears to have the best and most positive psychological effects.
There appears to be no significance between the psychological aspects of popliteal block and
ankle block anaesthesia.
Critical Evaluation of Previous Papers
Although for this study many references were used more in depth analysis is essential for
a couple of papers to identify clear views and results from previous authors as well as to
ensure a successful conclusion. The two papers to be analysed are:
Hansen E, Eshelman M, Cracchiolo A, (2000). Popliteal Fossa Neural Blockade as
the Sole Anesthetic Technique for Outpatient Foot and Ankle Surgery. Foot and
Ankle International 21 (1) 38-43.
33
Kelly A, Rudkin G, Dracopoulos G, (2000). Ankle block for forefoot surgery: patient
choice and efficacy. Foot and Ankle Surgery 6 249-254
The first paper, Hansen et al (2000) does provide a reasonable abstract. It provides a
summary of the study and although it does suggest at what conclusion was found there is
no mention of results or how the study was undertaken. The Introduction section lacks a
hypothesis and clear aims and objectives but does provide justification for the research
along with supportive evidence from previous studies. The methodology appears clear
and concise and provides information on anatomical considerations, study desigtn and
search strategies, however, it does not give the exact numbers of patient used in the
study. By scanning the rest of the paper the sampling size is explained later on in the
results section although it would be more appropriate to be mentioned here. This section
did provide information on ethical approval and statistical and economical analysis,
however there was a lack of information regarding participation and/or non-participation,
The exact technique of injection, amount of local anaesthetic and tourniquet pressures
used are clearly presented as part of the methodology. The results begin with explaining
the sample size and mentioned all necessary points including; age range, reasons for
participation and selection. There was a lack of statistical tests which would have
provided more versatile results and made comparisons to other studies results easier.
Tables and charts would have made the results easier to understand, however,
percentages were used. Non-participation was now mentioned and justified and the
individual procedures undertaken with the use of the local anaesthetic were explained. In
this paper the discussion and conclusion were brought together in one section. This
34
provides the thoughts of the author's on experimental findings with excellent
consideration and explanation with respect to other published work. A critique of the
methods and techniques used are also provided and the author's have recognised that a
larger, randomised control trial is required to prove their results. Thanking those who had
taken part in the study would have been respectful however, this was not done. The
references are acceptable and appropriately laid out.
The second paper, Kelly et al (2000) starts with an excellent abstract, although headed
"Summary". It provides a clear summary of the study including statistical results and how
the study was undertaken but does not mention the purpose of the study. The introduction
provides adequate justification for the research and is supported by a significant number
of key papers which are analysed and discussed in context to this and the other studies
mentioned. The aims of the research are clearly defined and a hypothesis although not
mentioned was not necessary for this study. The methodology begins by describing the
sampling size, exclusion criteria and ethical approval. Also mentioned is the pre
operative
information given to each patient in the trial and of detail taken from the patients on the
day of the procedure. An exact account of the drugs used, amount used, procedure type
and tourniquet pressures intra operatively are provided along with details on the
techniques applied. Statistical analysis and interpretation of the proposed results was also
discussed in this section. The results were well presented and easy to understand with the
use of tables, graphs and individual headings. Percentages and statistical tests used, this
enables the comparison of results with other studies. The discussion section gives the
35
advantages and disadvantages for both types of anaesthetic used in relation to the results
from this study and includes references from past research. There was no mention of any
further research needed. The use of exact percentages provided an accurate conclusion
and all interpretations of data appeared to be justified. The acknowledgements for those
involved in the study was admirable and all references were clearly presented.
The methodology of another paper is critiqued below to ensure further investigation into
the reliability of previous literature. Looking through the methodologies from other
studies used in this research it can be concluded that in general the methods sections
appear to include all necessary information with justifications. Often including tables to
enable easier reading and comparisons to the results section. Ethical approval was
completed in all the studies I have used for this research.
A study by McLeod (1995) provides an excellent example of a methodology. It includes
information on ethical approval, sampling size and exclusion criteria. All reasons for
non-participation were fairly justified. It describes the techniques used throughout the
procedure and the exact measurements e.g. amount of local anaesthetic used. Statistical
and economical analysis was also clearly mentioned here and tables supplied to show the
questionnaires used and patient data. This enabled easier interpretation of the information
and clarification of statistical tests used. This methodology is clearly and concisely
written and includes all the information required with significant justifications.
36
Chapter Three: Results
Results from previous studies
A study by Lee et al 1996 found that regional anaesthesia was successful in 99.1% of cases.
A follow up survey was completed by 164 patients from this 162 patient stated that "they
would prefer to have the surgery performed in the same fashion" (Lee et al 1996). During
research it was obvious that there is a lack statistical tests associated with results from passed
37
studies and this makes analysis of previous conclusions difficult. Percentages appear to be
the most common way of determining the success of the study and these can be noted below.
Visual analogue scales were also a popular way of collecting results from studies and are
explained in a later section.
Popliteal blockade
A study by Provenzano et al (2002) the authors produced successful popliteal blocks in 82%
of cases. It was found that those who had a successful block, only 12% required systemic
analgesics after the local anaesthetic had worn off compared to 60% of the unsuccessful
group. This study also found that 9 out of the 13 patients who received a popliteal block
solely for postoperative pain did not required any additional systemic analgesics.
A study by Hansen et al (2000) had a success rate of 95% and all patients intraoperatively
tolerated a pneumatic calf tourniquet without complaint. The procedures completed using this
anaesthetic technique were, Ankle arthroscopy, achilles' tendon repair, hardwear removal,
ankle ligament repair, bunionectomy and open reduction and internal fixation of fractures.
Post operatively all patients were satisfied with the anaesthetic technique and 14% told the
anaesthesia team that the popliteal block was superior to previous general anaesthetic
experiences.
White et al (2003) completed a randomised controlled study where 24 patients underwent
foot or ankle surgery under general anaesthetic, all patients also received 0.25% 30mL
bupivacaine before surgery. A catheter was inserted and two groups were set up, group 1
38
received saline 0.9% (control) at a consent rate of 5mL/h for up to 48hurs after surgery.
Group 2 received 0.25% bupivacaine at the same rate. Pain scores were recorded at 24hr,
48hr, 72hr and 1week post operatively and the bupivicaine group showed statistically
significant reduction in the maximal pain scores (>50%) and in opioid use (>60%) compared
to the control group. In addition, 40% of the patients in group 2 were able to return home on
the day of the surgery where as no patients in the control group left on the same day.
As mentioned earlier in a study by McLeod et al (1995) found that the popliteal nerve block
lasted an average of 18 hours. Compared to 11.7 hours average analgesia of ankle block.
Ankle block
Delgado-Martinez et al (2000) found that in their study there was a 98% success rate of ankle
block anaesthesia. When completely blocking all the nerves that innovate the foot the patient
was pain free intra operatively in 89% of cases but only 43% were pain free when a selective
block was performed (significance of < 0.01).
McLeod et al (1995) found in a study where there was no differences between two groups in
age, weight, operation or duration of anaesthesia. One group under went surgery with the use
of popliteal nerve blockade and the other group had surgery using ankle nerve blockade.
39
There was no difference in patient satisfaction in post-operative analgesia between the two
groups, 95% of the popliteal blocked group and 89.5% of the ankle blocked group. However,
more patients (43%) from the popliteal blocked group required morphine analgesia in post
anaesthetic recovery compared to only 16% of the ankle blocked group. Therefore, the
authors of this study conclude that the ankle block technique is more reliable than the
popliteal block.
When referring to text, research has shown that it is widely accepted that for ankle blocks a
mixture of 0.5% bupivacaine with 1% lidocaine is reliantly successful. This provides a fast
onset with prolonged post-operative analgesia.
Visual Analogue Scale
Rating scales are the most commonly used way of identifying pain levels. The
visual analogue scale is just one and has been used by many previous authors.
It identifies the level of pain experienced by the patient at specified times during and
after the surgical operation. They consist of a 10cm horizontal line where the left hand
side indicated no pain and the right hand side indicated the worst pain ever experienced
on which the patient is requested to make a vertical mark along the line to show the level
of pain experienced. The mark is then measured from the left hand side to identify the
40
amount of pain usually scored out of a possible 100 points (Needoff (1995) Charlton (1997).
It can be used following the use of any anaesthesia and any procedure, but is most
commonly used following a popliteal or ankle nerve block. This is a simple way to measure
pain levels and is easy for both the patient to understand and the surgeon to interpret.
Finsen et al (1997) used this scale to determine pain related to tourniquet use in forefoot
surgery. They tested the pain levels 10minutes into the surgical procedure and 3minutes after
the release of the tourniquet. Other levels of rating pain include using number scales
commonly ranging from 0 being no pain to 10 being the worst pain ever experienced .
Abrahm (1999), Delgardo-Martinez et al (2001) and White et al (2003) or pointer systems
Mcleod (1995)
After any surgical operation with or without the use of rating scales it is important to ask
questions to the patient to ensure pain type and levels are normal expectations with relation to
the procedure. It must be identified where the pain is e.g. if the patient complains that they
have pain all over the body, stress, anxiety and possibly fever are indicated. Whereas pain
distant from the operative site may suggest un related complications. A description of the
type of pain may also rule out any abnormalities. For example, if the patient complains of
numbness or tingling, nerve compression or ischaemia may be present however, a sharp,
stabbing pain is normally expected following any surgical procedure. For examples of pain
scales please refer to appendix A.
41
Conclusion
As the majority of elective foot and ankle operations are performed on an outpatient basis
rapid turnover of patients and high patient satisfaction is vital. To ensure the smooth running
of podiatric theatres anaesthesia should provide quick administration, quick onset, correct
usage for ambulatory operations, good intraoperative anaesthesia, fast uneventful recovery
and effective postoperative analgesia. Taking this into account regional anaesthesia offers an
excellent anaesthetic choice.
It is widely and universally accepted that regional anaesthesia is safer than general
anaesthesia although there is a lack of scientific evidence to support this. Peripheral nerve
blocks as described earlier, presents many advantages in foot and ankle surgery with the
42
reduction of undesirable side effects related to general anaesthesia. The cost of a complete
operation using local anaesthetic blocks is cheaper than using general anaesthetic. This is
because there is no need for an anaesthetist and a post operative care team (required after
surgery using general anaesthetic) can be replaced by an intensive in-theatre care team.
Along with this there is no requirement for a hospital stay following local anaesthetic
injection. All these factors reduce the total cost. Patients with contra indications to general
anaesthesia respond well to regional and is undoubtedly the anaesthetic choice of the
majority of patients undergoing foot and ankle surgery.
There are potential advantages to limiting the extent of anaesthesia to the most distal
neuronal tree. To begin with, the more distal the neural blockade, the easier the access to
nerves. Also if the local anaesthetic is injected more peripherally the systemic absorption is
of a lesser magnitude. The side effects associated with neuraxial anaesthesia e.g.
cardiovascular and respiratory depression are avoided by the used of peripheral blocks.
Popliteal blocks are particularly useful when there is infection and/or soft tissue swelling
present at the ankle area.
Regional anaesthesia techniques also provide a level of postoperative pain management
following foot and ankle surgery which no other type of anaesthesia achieves. Prolonged
postoperative analgesia in peripheral nerve blocks can be achieved by using a longer-acting
local anaesthetic agent. Epinephrine or clonidine can be added to solutions of local
anaesthetic to increase the analgesic duration and often when injecting bupivacaine with
epinephrine for a popliteal block, sensory blockade can be achieved for 12-24 hours. It must
be noted that epinephrine must not be used for ankle or metatarsal blocks due to the risk of
ischemia. However, lidocaine (10mcg/ml) with clonidine can be used for ankle or metatarsal
43
blocks with similar effects (increase in duration and quality of postoperative pain relief). An
advantage to using a popliteal nerve blockade is that a catheter can be placed in the epineural
sheath of the sciatic (popliteal) nerve and continuous infusion of local anaesthetic can occur,
this is another way of increasing postoperative analgesia.
Sedation when using peripheral nerve blocks for podiatric surgery provides the benefits of
both general and local anaesthetics. There is a reduction in post operative nausea and
vomiting although drowsiness can last for approximately one hour afterwards.
. Ankle block anaesthesia and popliteal block anaesthesia appear to have similar success rates
with regards to previous studies, so it can not be stated that one is better than the other.
However, when looking at the advantages and disadvantages for both it is clear that ankle
block anaesthesia has more benefits than popliteal block anaesthesia. As stated earlier for an
ankle block there are no requirements for a nerve stimulator, an experienced operator or post
operative walking devices e.g. crutches. Using an ankle block for podiatric surgery provides
and average of 11.5 hours (Mcleod et al) which allows the patient time to get used to the post
operative requirements of the surgery e.g. resting and taking pain killers and appears to be
effective and successful with high levels of patient satisfaction. The same foot and ankle
surgical procedures can be performed under both anaesthetics and it is only when surgery is
to include areas above the ankle that an ankle block can no longer be utilised. The literature
suggests that an ankle tourniquet is sufficient for foot and ankle procedures as stated earlier
Finsen et al 1997 found that this to be as successful as a calf tourniquet. With sedation it has
been proposed that a thigh tourniquet can be utilised (Lee et al 1996).
All the literature shows that an ankle block should be the anaesthetic of choice for podiatric
surgery however each case must be assessed on an individual basis using the factors
mentioned throughout this study.
44
APPENDIX A
Visual Pain Scales These visual pain scales are typical of the scales described earlier in chapter three: the results section pg. 36-37.
45
Charlton E. (1997) The Management of Postoperative Pain. Updates in Anaesthesia. 7 (2) 2-7.
Appendix B
46
Abrahm J.L (1999) Management of Pain and Spinal Cord Compression in Patients with Advanced Cancer. Annals of Internal Medicine 131 37-46.
References
Abrahm J.L (1999) Management of Pain and Spinal Cord Compression in Patients with Advanced Cancer. Annals of Internal Medicine 131 37-46.
47
Bonnet F, Houhou A, Avleine C, (2000) Alpha 2 Adrenergic Agonists and Anaesthesia. European Society of Anaesthesiologists 9 RC 3 1-6 Bukbirwa H, Conn D.A, (1999). Toxicity from Local Anaesthetic Drugs. Update in Anaesthesia 10 (8) 1-4 Charlton E, (1997). The Management of Postoperative Pain. Update in Anaesthesia. 7: (2) 1-7 Chaurasia S.K, Kane D.G, Chaudhari L.S. (1999). A comparative stuidy of clonidine versus a combination of diazepam and atropine for premedication in orthopaedic patients. Journal of Postgraduate Medicine 45 (3) 74-78. Collins SL, Moore RA, McQuay HJ (1997). The Visual Analogue Pain Intensity Scale: What is Moderate Pain in Millimetres? Pain 72 (1-2) 95-7. Delgardo-Martinez M.D, Marchal J.M, Molina M, Palma A. (2001). Forefoot Surgery With Ankle Tourniquet: Complete or Selective Ankle Block? Regional Anesthesia and Pain Medicine 26 (2) 184-186 Delgardo-Martinez M.D, Marchal-Escalona J,M. (2001). Supramalleolar Ankle Block Anesthesia and Ankle Tourniquet for Foot Surgery. Foot and Ankle International 22 (10) 836-838. Finsen V, Kasseth A, (1997). Tourniquets in Forefoot Surgery. The Journal of Bone and Joint Surgery 79-B (1) 99-101 Hansen E, Eshelman M, Cracchiolo A, (2000). Popliteal Fossa Neural Blockade as the Sole Anesthetic Technique for Outpatient Foot and Ankle Surgery. Foot and Ankle International 21 (1) 38-43. Heath M, (1982). Deaths after intravenous regional anaesthesia. British Medical Journal 285 913-914 Kelly A, Rudkin G, Dracopoulos G, (2000). Ankle block for forefoot surgery: patient choice and efficacy. Foot and Ankle Surgery 6 249-254 Lee T.H, Wapner K.L, Hecht P.J, Hunt P.J. (1996) Regional Anesthesia in Foot and Ankle Surgery. Orthopedics 19 (7) 577-580 Provenzano D.A, Viscusi E.R, Adams S.B, Kerner M.B, Torjman, Abidi N.A. (2002). Safety and Efficacy of the Popliteal Fossa Nerve Block when Utilized for Foot and Ankle Surgery. Foot and Ankle International 23 (5) 394-399
48
Maze M, Segal IS, Bloor BC (1988) lonidine and other alpha2 adrenergic agonists: strategies to the rational use of these novel anesthetic agents. Journal of Clinical Anesthesia 1(2) 146-57 McCormick B.A, (1999). Ankle Blocks. Update in Anaesthesia 10: (13) 1-2. Mcleod D.H, Wong D.H, Vaghadia H, Claridge R.J. (1995). Lateral popliteal sciatic nerve block compared with ankle block for analgesia following foot surgery. Canadian Journal of Anaesthesia 42 (9) 765-769 Mendicino R.W, Statler T.K, Catanzariti A.R (2002). Popliteal Sciatic Nerve Blocks after Foot and Ankle Surgery: An Adjunct to Postoperative Analgesia. The Journal of Foot and Ankle Surgery 41 (5) 338-341 Mercandetti M, (2002). Anesthesia, Local with Sedation. Emedicine 1-10. Morphett S, (2000). Nerve Blocks for Anaesthesia and Analgesia of the Lower Limb - A Practical Guide: Femoral, Lumbar Plexus, Sciatic. Update in Anaesthesia 11 (12) 1-5. Needoff M, Radford P, Costigan P (1995). Local Anesthesia for Postoperative Pain Relief after Foot Surgery: A Prospective Clinical Trial. Foot and Ankle International 16 (1) 11-13. Price DD, Bush FM, Long S, Harkins SW (1994). A Comparison of Pain Measurement Characteristics of Mechanical Visual Analogue and Simple NumericalRating Scales. Pain 56 (2) 217-26. Reilley T.E, Gerhardt M.A (2002). Anesthesia For Foot and Ankle Surgery. Clinics in Podiatric Medicine and Surgery 19 (1) 125-147 Rongstad KM, Mann RA, Prieskorn D, Nicholson S, Horton G (1996). Popliteal sciatic nerve block for postoperative analgesia. Foot and Ankle International 17 371-376. Sunita G, Swati D, Shanti P. (2002). Intravenous Regional Anaesthesia Using tramadol Hydrochoride and Ketorolac: A Double Blinded Controlled Study. Indian Journal of Anaesthesia 46 (5) 369-372. Tagoe M, Rees S. (1998). Poplteal nerve blocks extend the scope of day case surgery. The Foot 8 154-157. Tuckley J.M, (1994). The Pharmacology o f Local Anaesthetic Agents. Update in Anaesthesia 4 (7) 1-3. Wallace G.F, (1991). Complications of Anesthesia. Clinics in Podiatric Medicine and Surgery 8 (2) 425-433
49
Warner M.E, (2003). Sedation and Analgesia for diagnosis and Therapeutic Procedures. Anesthesiology 99 (6) 1465-1466. White P.F, Issioui W.P, Skrivanek G.D, Early J.S, Wakefield C. (2003) The use of a continuous popliteal sciatic nerve block after surgery involving the foot and ankle: does it improve the quality of recovery? Anesthesia and Analgesia 97 (5) 120-1309 Wooden S.R, Sextro P.B, (1990) The ankle block: Anatomical review and anesthetic technique. Journal of the American Association of Nurse Anesthetists 58 (2) 105-111.
Bibliography
Palastanga N, Field D, Soames R. (2001) The Lower Limb. 3rd ed. Anatomy and Human Movement Structure and Function.Oxford. Butterworth Heinmann, Thomas VN (1997) Pain: Its Nature and Management. 1st ed. London. Baillie Tindall.
50
Mckenzie I, Gaukroger PB, ragg P, Brown T (1997) Manual of Acute Pain Management in Children. 1st ed. London. Churchill Livingstone. Smith C.E, (2003) Clinical Use of dexmedetomidine. Management of ICU Patients. Ohio, USA. Case Western Reserve University. www.nysora.com - Anesthesia for Ankle and Foot Surgery.
Recommended