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P.N.REDDY-HYCOME 2004
BRACHIAL PLEXUS BLOCKA REVIEW
Dr.P.NARASIMHA REDDY M.D D.APROFESSOR & H.O.DDEPT. OF ANAESTHESIOLOGYKURNOOL MEDICAL COLLEGEKURNOOL
P.N.REDDY-HYCOME 2004
Brachial plexus- a review
• 1)Introduction • 2)Brief history• 3)Applied anatomy• 4)Approaches to brachial plexus• 5)Techniques of brachial plexus block• 6)Some relevant facts• 7)Complications• 8)Future research
P.N.REDDY-HYCOME 2004
Introduction• The word plexus means to twine. It implies a
network of nerves or vessels.• “Man uses his arms and hands constantly.. As a result he exposes his arms and hands to
injury constantly.. Man also eats constantly… Man’s stomach is never really empty.. The combination of man’s prehensibility and
his unflagging appetite keeps a steady flow of patients with injured hands and full stomachs streaming into hospital emergency rooms.
DAVID LITTLE 1963.
P.N.REDDY-HYCOME 2004
Introduction
• To give a successful block One must have
1) Perfect anatomical knowledge of nerves and dermatomal distribution.
2) Perfect knowledge about local anaesthetic agents, complications and side effects.
3) Perfect technical skill which is gained by experience.
P.N.REDDY-HYCOME 2004
HISTORY
• 1884 – Karl koller used cocaine in clinical practice.• 1859 – 1922 – Karl ludwig used infiltration
anaesthesia.• 1884 – Halstead
Matas
Crile injected local anaesthetic directly into the nerves.
- Hirschel injected brachial plexus blindly.• 1912 – Kulen Kampff after experimenting on
himself used supraclavicular technique.
P.N.REDDY-HYCOME 2004
History
• 1922 – Gaston Labott used axillary block.
• 1940 – MacIntosh and Mushin modified Kulen Kampff block and wrote a monogram on supraclavicular block.
• 1964 – Alon P Winnie described pervascular sheath and block.
P.N.REDDY-HYCOME 2004
APPLIED ANATOMY
• Except for cutaneous supply to upper medial aspect of the arm and uppermost aspect of shoulder entire supply to the arm is by brachial plexus.
• Anterior primary divisions(or roots) of C5-8 to T1(C4- prefixed, T2 – postfixed).
• Roots unite to form three trunks.• Trunks converge on to the first rib and divide into
anterior and posterior divisions.• These divisions unite in the axilla to form cords.• The plexus gives rise to 21 nerves, 9 above the
clavicle.
P.N.REDDY-HYCOME 2004
Applied Anatomy Name peripheral S.branches Axillary upper lat. Cut. N. of arm lower lat. cut. N. of arm Radial post. Cut N. of arm
Post. Cut. N. of forearm Cut. To dorsum of hand
Ulnar Cut. To dorsum of hand and palm
Median Cut. To dorsum of hand and palm
Musculo cut. Nerve Lat. Cut. N. of forearm Medial cutaneous nerve of arm and forearm araise directly from
medial cord. with interscalene approach c8 and t1 are likely to be missed
and in axillary block musc. Cut. And radial nerves are likely to be missed.
In such situations brachial block with selective nerve blocks will give good results and prolonged post operative pain relief.
P.N.REDDY-HYCOME 2004
P.N.REDDY-HYCOME 2004
Applied Anatomy
Rule of 3 and 5 roots 5 C5-TI
Trunks 3 superior(C5-C6) Middle (C7) Inferior (C8-T1)DIVISONS 3 Anterior
3 PosteriorCords 3 Lateral medial
posteriorTerminal nerves 5 Median(lat and med. Cords) Musculo c.N. (Lat. Cord) ulnar (Med. Cord)
Axillary (Post. Cord) Radial(Post. Cord)
P.N.REDDY-HYCOME 2004
Applied Anatomy
• Peripheral nerves:
Both sensory and motor supply of upper limb from infraclavicular part of B.P.
Because of interconnection of 5 nerve roots there is overlapping and difference between dermatomal, myotomal and sclerotomal distribution of individual nerves.
Seven major configurations of B.P are noted.in 61% there is left to right asymmetry.
P.N.REDDY-HYCOME 2004
Applied Anatomy
• Relationships:
vertebral A. travels cephalaud and enters bony canal ar C6.
Cervical roots are just post. To vertebral A.
Ext. Jugular vein overlies the interscalene groove at C6.
Over the first rib the divisions of B.P lie post., cephalaud and lat. To subclavain A.
Axillary A. lies ant. To radial N., Postero medial to median nerve, Posterolateral to ulnar N.
P.N.REDDY-HYCOME 2004
Applied Anatomy
Non brachial plexus anatomy: 1) supraclavicular nerve (c3-4) provides
sensory supply to ‘cape area’ 2)suprascapular nerves (C5-6) sensory
fibers to the posterior aspect of the shoulder capsule, acro. Cla. Jt., cut. Supply to proximal third of arm in the axilla.
3) Intercostobrachial nerve (T2) with medial cut. N. innervates upper half of the post. And medial side of skin of the arm.
P.N.REDDY-HYCOME 2004
P.N.REDDY-HYCOME 2004
Applied Anatomy
Sensory innervation of the arm: It is to determine
which cut. N. distribution is with in the surgical field,
which terminal nerves require supplementation in partial block and
Determine pre and post operative neurological deficits.
P.N.REDDY-HYCOME 2004
Applied Anatomy
Motor innervation of the arm: It is important when we are using PNS to elicit end point.
Sup. Trunk stimulation at ISC groove- shoulder elevation.
Median nerve stimulation – forearm pronation, wrist flexion and thumb opposition.
Ulnar nerve stimulation – ulnar deviation of wrist, finger flexion and thumb adduction.
Radial nerve stimulation – extension of wrist and fingers.
Assessment of efficiency of block can be done by evaluating the function of each individual nerve.
P.N.REDDY-HYCOME 2004
Applied Anatomy
• Rule of 4 P’s:1) Patient is asked to push the arm by
extending the forearm at the elbow (radial nerve).
2) To pull the forearm at the elbow(Musc. Cut.N.).
3) Ability to distinguish a Pinch at the palmar base of index finger (Medain N).
4) Ability to distinguish a pinch at the palmar base of little finger(Ulnar N).
.
P.N.REDDY-HYCOME 2004
Choice of approach
• Depends on
1) site of surgery
2) duration of surgery
3) surgeon
4) anaesthetist
5) Patient.
P.N.REDDY-HYCOME 2004
Approaches to brachial plexus
• Inter scalene block(ISB):
Surgery on the shoulder
can spare C8-T1(ulnar in 50%)
Poor for arm and hand surgery
10-15ml of L.A
Central neuraxial blockade
vagal or phrenic nerve blockade
Pneumothorax rare
Intravascular injection a possibility
P.N.REDDY-HYCOME 2004
INTERSCALENE BLOCK
P.N.REDDY-HYCOME 2004
Approaches- contd.
• Supraclavicular block:
Provides anaesthesia for entire extremity
“No parasthesia- No Anaesthesia” an aphorism by- Dr. Moore is more appropriate
BID success rate is more than 95%
It is modified by Macintosch
Vertical method “Plumb-Bob” method
P.N.REDDY-HYCOME 2004
P.N.REDDY-HYCOME 2004
P.N.REDDY-HYCOME 2004 SUPRACLAVICULAR BLOCK
P.N.REDDY-HYCOME 2004
Approaches contd.
Inter sternocledomastoid block:
For hand and arm surgery
Needle is directed laterally placed in between the two heads of the sterno-mastoid muscle
Catheter insertion is easy and safe
Less risk of pneumothorax
15% failure in ulnar distribution
P.N.REDDY-HYCOME 2004
CONTINOUS INTERSCALENE BLOCK
P.N.REDDY-HYCOME 2004
Approaches contd.
• Infraclavicular block (coracoid approach):
For surgery on arm and hand
More consistent anaesthesia for axillary and MUSC. Cut.N.
Latency more
No changes in pulmonary function
Catheter fixation is easy
P.N.REDDY-HYCOME 2004
INFRACLAVICULAR BLOCK
P.N.REDDY-HYCOME 2004
INFRACLAVICULAR BLOCK
P.N.REDDY-HYCOME 2004
Approaches contd.
Axillary block(AXB):
• For hand surgery
• All techniques work at terminal branches level
• Success rate 60-100%
• Anaesthesia of MCN is done by a separate injection into the belly of coracobrachialis
P.N.REDDY-HYCOME 2004
AXILLARY BLOCK
P.N.REDDY-HYCOME 2004
Approaches contd.
• Mid humeral block 1994 By Dupre
Each individual nerve is located at the junction of upper one third to the lower two thirds of the humerus in the humeral canal.
Success rate is very high
Latency less
Low volume of L.A.
Time consuming
P.N.REDDY-HYCOME 2004
TECHNIQUES FOR BP BLOCK
Fascial clicks: Mostly we depend on fascial clicksWell appreciated with short beveled needlesMany studies gave mixed results• Paraesthesias:An abnormal sensationIndicate that the needle tip is near the nerveThey also indicate nerve injuryRepeated or exaggerated parasthesias are
undiserable Success rate – 70 to 90%
P.N.REDDY-HYCOME 2004
Techniques Cont…. PNS:
Is popularised by Raj. P in peripheral nerve blocks
Success rates are high
Latency is very less
Nerve injuries are less
Motor response with ≤ 0.5mA gives successful blocks
Pitfalls are: Correct polarity of the needle
P.N.REDDY-HYCOME 2004
Techniques Cont….• PNS Cont… Pitfalls are: Correct polarity of the needle is
important Positive electrode should be secured to
the patient Loose connections and flat batteries to be
avoidedMotor response should be in the distal
group of musclesNerve damage can occurCompartmental syndrome can occur
P.N.REDDY-HYCOME 2004
Techniques Cont..• Transarterial:Penetration of artery is a good indication of
needle in the axillary sheathStan et al. – showed that it is very safe with
minimal complications and high success rateCocking’s – A single injection of large volume.
Success rate – 99%• Perivascular:BP is enveloped by fibrous sheath from cervical
spine to midportion of forearmA.P Winnie suggested large volume of single
injection into the sheath will suffice
P.N.REDDY-HYCOME 2004
TRANSARTERIAL TECHNIQUE
AXILLARY BLOCK
P.N.REDDY-HYCOME 2004
Techniques Cont….
• Perivascular Cont
It was challenged by Thompson. He said each nerve is in separate sheath
Rorie described septae in neurovascular bundle, demonstrated compartmentalization of dye. This explains profound/partial block
Patridge, Katz and Benirschke demonstrated septae but they are very thin and incomplete
Communication exist in between septae
Touch and feel is the main guiding principle
P.N.REDDY-HYCOME 2004
Techniques Cont….
• Imaging techniques:
Fluroscopy and ultrasound
U /s of blood vessels used to assist BP Block
Recently u /s nerves described
This is the future promise for the
Anaesthetists
Drawbacks: 1.Interpretation 2.Size of the probe 3.2/3 dimensional views 4.No functional end point
P.N.REDDY-HYCOME 2004
Techniques Cont…..
• P.E.G (Percutaneous Electrical Guidance):
By W. Urmey. F
This is a new technique
Involves indentation of skin and transcutaneous stimulation with cylindrical smooth tipped electrode probe to locate desired and later to guide a block needle to the nerve
Grossi proposed concept of anaesthetic line.
P.E.G. concept works well with anaesthetic line
P.N.REDDY-HYCOME 2004
Techniques Cont…..
• Single versus multiple injections:
Still it is not clear which one superior
AXB using 2,3 and 4 injections reported high success rate
More complete block, less anaesthetic agent and shorter latency
Incidence of neuropraxia is 1.7%
Time consuming
P.N.REDDY-HYCOME 2004
Techniques Cont…..
• Continuous techniques:
Exiting and evolving areas of block
Particular approaches are useful
Catheter fixation is difficult
Migration of catheter
Use of large bore needles and prolong searching for nerves
Injection any solution
P.N.REDDY-HYCOME 2004
SOME GUIDING PRINCIPLES FOR BP BLOCK
• SEDATIVE DRUGS:Titration is very importantNo drug absolutely prevents drug toxicityPatient should not be unconcious• LOCAL ANAESTHETIC AGENTS:Higher concentrations not necessaryMixing is not very usefulAlkalnization gives useful resultsRate of convulsions per 1000 blocks:
(A)1.2-epidural (B)1-2.8 axillary (C)7-8 interscelene/supraclavicular
P.N.REDDY-HYCOME 2004
Guiding principles cont…..
• LA Cont……
Drugs Duration
(hrs)
Concentr-- ation (%)
Dose
(mg / kg)
Lidocaine 4-7 0.5-1 7mg with adrenaline
Bupivacaine 8-12 0.25-0.5 2-3
Ropivacaine 8-10 0.25-0.5 2-4
P.N.REDDY-HYCOME 2004
Guiding principles cont….
• Vasoconstrictors:
Epinephrine is the drug. 1:2,00,000 is appropriate
Freshly made solution
• Equipment and needles:
Nondisposable syringes
Sterility
Short bevel needles are best
P.N.REDDY-HYCOME 2004
Guiding principles cont….
• Additives:
Many drugs to LA to potentiate and to prolong the block
Ketamine BuprenorphineClonidine Tramadol Neostigmine
P.N.REDDY-HYCOME 2004
Guiding principles cont….
• Measuring success of block:
Difficult to measure
Always some legal, political, social, educational and personal reasons to use additive drugs
Not an excuse for sloppy technique or inappropriate dosing
P.N.REDDY-HYCOME 2004
COMPLICATIONS• Incidence: Extremely rare• France study of 21,278 blocks cardiac
arrest – 0.01%
death – 0.005%
seizures – 0.8%
radiculopathy – 0.02%• ARNI(Anaesthesia Related Nerve Injuries)
16% of ASA claims
Out of these 8% ulnar, 20%BP
RA did not increase the risk of neuropathy in patients with preexisting neuropathy
P.N.REDDY-HYCOME 2004
Complications cont…
• Peripheral nerve injuries:
Residual paraesthesia, hypoasthesia and rarely permanent paresis
Early onset indicates extra or intra neural haematoma or injection or edema
Late onset suggests tissue reaction or scar formation
P.N.REDDY-HYCOME 2004
Complications cont….
• Factors contributing to nerve injuries:
Categories Pre op. risk factors
Patient factors Preexisting neurological disorders
Male, old age,extemes of body habitus, DM
Surgical factors Surgical trauma, strech of nerves, tourniquet ischemia, vascular compromise, peri op. imflamation, post op. infection, hematoma, cast compression, pt. position
Anaesthesia factors
Needle or catheter trauma, vasoconstrictors, perineural edema, LA toxicity
P.N.REDDY-HYCOME 2004
Complications cont….
• Factors that contribute directly to ARNI include:
1. Mechanical trauma
2. Ischemic injury and
3. Chemical injury
P.N.REDDY-HYCOME 2004
Complications • MECHANICAL TRAUMA:
Needle:
Trauma depends on type of needle and elicitation of parasthesias
Selander et al. examined 24hr histological changes in rabbit sciatic nerve
injury more with long bevel needles(14° vs 45°short bevel)
severity of injury more with short bevel needles
Rice Mc Mahan – observed parallel insertion of needle – less injury than transverse insertion
P.N.REDDY-HYCOME 2004
Complications cont….• Mechanical trauma cont….
Parasthesias:
Whether elicitation of parasthesias cause
direct needle trauma there by increasing the risk of nerve injury is unknown
Selander reported higher incidence of ARNI when parasthesias are sought in AXB with perivascular technique (2.8% vs 0.8%)
Auroy et al. noted cases of radiculopathy associated with parasthesias are pain during injections
P.N.REDDY-HYCOME 2004
Complications cont….
• Parasthesias cont…
Winchell and Wolfe reported 0.36% of ARNI despite 98% of patients experiencing parasthesias.
Moore’s contension was mechanical parasthesias during RA are persae not an indication of nerve injury
Pain during injection increases the risk
Supplimental injection after a failed block or under GA increases the risk
P.N.REDDY-HYCOME 2004
• ISCHEMIC INJURYFunctional integrity of nerve depends on its
micro circulationIntrinsic supply of exchange vessels within the
endoneuriniumExtrinsic supply of larger nutritive vessels
which are under control of sympathetic system and responds with epinephrine containing solutions
NBF(Neural Blood Flow): Plain 2% lidocaine reduces NBF by 39%. By adding adrenaline 1:2,00,000 NBF reduced by 78%.
complications
P.N.REDDY-HYCOME 2004
Complication cont….
• Ischemic injury cont…Epinephrine: Adrenaline is safe when added
to nerve bundles in appropriate concentrations with intact barrier mechanisms (blood neural barrier)
Epinephrine may increase the risk with disrupted barrier mechanism or by decreasing the NBF as in intraneural injection or chemotherapy related neurotoxicity, DM neuropathy or atherosclerosis
P.N.REDDY-HYCOME 2004
Complications cont…• Ischemic injury cont…
Neural edema: Can occur after intraneural injection of LA
Intraneural pressure may go upto 100mm of Hg for up to 15min after injection
Increased pressure interferes with microcirculation or alter the permeability of BNB
Results in degeneration and dystrophy of axons. Fibroblasts proliferation causes late changes, increasing perineural thickening and endoneural fibrosis
P.N.REDDY-HYCOME 2004
Complications .
• CHEMICAL INJURY
In clinical concentrations LA are safe to the nerves
Higher concentrations, prolonged exposure and intraneural injection cause damage
Both long acting, short acting with or without adrenaline can cause changes depending on the concentration
Continuous catheters – more incidence of injuries
Most of the time the injury may be single or combined.
P.N.REDDY-HYCOME 2004
Complications cont…• VASCULAR INJURIES: Rare but potentially dangerousIn anticoagulated patients definite guidelines not
available. Benefits must be weighed against the risks
Transient vascular insufficiency: Reported in AXB, may be due to intra-arterial puncture. Incidence 1%
Hematoma: 0.001-0.02%. May or may not be associated with post operative nerve problems
Pseudo-aneurysm and axillary artery dissection is reported
P.N.REDDY-HYCOME 2004
Complications cont….
• MUSCLE INJURIES:
Necrosis can occur at the site of injection
More so with bupivacaine
Depends on dose, time of exposure and calcium levels in muscles
Hemidiaphramatic paralysis(HDP):
ISB – 90 to 100%, mild dyspnoea, 25 – 30% reduction in RS function, ropivacaine is not protective, abnormal RS function persists for 24hrs in 50% of patients
P.N.REDDY-HYCOME 2004
Complications
• PNEUMOTHORAX:
Common in SCB
Also occurs in ISB and ISCB
Plumb-bob technique reduces the incidence
Careful with tall, thin and emphysematous patients
Symptoms occur after 6 – 12hrs after injection
Immediate symptoms if patients is on IPPV
P.N.REDDY-HYCOME 2004
Complications • LA REACHING UNINTENDED PLACES:
Intravascular injection: 0.2% in transarterial Can occur in ISB and SCB Direct injection or retrograde flow via subclavian
artery Convulsive dose of bupivacaine is 3.6mg,
lidocaine is 14.4mg Safety margin
bupivacaine:l-bupivacaine/ropivacaine:lidocaine
1 : 2 : 9
P.N.REDDY-HYCOME 2004
Complications
• LA Reaching unintended places cont…Subarachnoid/epidural space: Common in ISB Needle enters directly or via dural cuff Avoided by shorter needles and directing the
needle cauded Slow, fractionated dosesCervical sympathetic chain: Horner’s syndrome – common in ISB, SCB 20 to 90%, no harmRecurrent laryngeal nerve block: Common in ISB and SCB – 1.3%. Hoarseness
of voice. Treatment: Reassurance
P.N.REDDY-HYCOME 2004
Complications
• HYPOTENSIVE / BRADYCARDIAC EVENTS(HBE):
13 – 24% patients develop HBE in shoulder arthroscopy under ISB
Mechanisms could be1. β-agonistic effects of epinephrine or
activation of Bezold-Jarisch reflex HBE is reduced by prophylactic
metaprolol but not glycopyrrolate Metaprolol 2.5mg increments upto 10mg
or to get HR about 60/min
P.N.REDDY-HYCOME 2004
Complications
• TOURNIQUET EFFECTS:Ischemic injury under the compressed area
occurs with in 2-4hrsIn non compressed area occurs at about 6hr40min needed re-establish normal status after
deflationPain of tourniquet by complex mechanism –
neural ischemia transmitted by nonmyelinated C fibres
Pain disappears immediately after deflation
P.N.REDDY-HYCOME 2004
Complications • LIMB PROTECTON AND DISCHARGE
CRITERIA: No RCT data Prolonged blocks can increase the risk of
nerve injury Can be discharged with partial sensory block
with instructions to avoid thermal or pressure injuries
Fitted with a sling or protective device Mid Humeral block is best Blocking the individual nerves with different
agents
P.N.REDDY-HYCOME 2004
Recommended