REGIONAL ANESTHESIA IN CATTLE

By

ERMIAS GEBEYEHU

A Paper Presented for the Course: Seminar on Animal Health (VST-566)

UNIVERSITY OF GONDAR

FACULTY OF VETERINARY MEDICINE

May, 2014

GONDAR

I

ACKNOWLEDGMENTS

Above all, I would like to thank the almighty GOD and his Holly mother St. Marry who gave me

strength to accomplish this seminar paper.

I forward my immense gratitude to my advisor Prof. Rajendran Natarajan for his kindness in

hospitality, constructive ideas and corrections; he had made during the course of my seminar review.

Last but not least, my gratitude and respect extend to my lovely family for their overall moral and

financial support.

II

TABLE OF CONTENTS

ACKNOWLEDGMENTS ............................................................................................................. I

TABLE OF CONTENTS ............................................................................................................. II

LIST OF ABREVIATION ......................................................................................................... III

LIST OF FIGURES .................................................................................................................... IV

LIST OF TABLES ........................................................................................................................ V

SUMMARY ................................................................................................................................. VI

1. INTRODUCTION .................................................................................................................. 1

2. LITRATURE REVIEW ON REGIONAL ANESHESIA IN CATTLE ............................ 3

2.1. Historical perspective of regional anesthesia in cattle ..................................................... 3

2.2. Local anesthetics ................................................................................................................. 4

3. REGIONAL NERVE BLOCK AND ITS TECHNIQUE IN CATTLE ........................... 7

3.1. Regional nerve block of head.7

3.1.1. Cornual nerve block........................................................................................................ 7

3.1.2. Auriculopalpebral nerve bock ........................................................................................ 8

3.1.3. Retrobulbar nerve block ................................................................................................. 9

3.1.4. Peterson nerve block in cattle....................................................................................... 10

3.2. Regional nerve bock of trunk of cattle ............................................................................ 11

3.2.1. Proximal paravertebral nerve block (Farguharsons method) ...................................... 11

3.2.2. Distal paravertebral nerve block (Magda method) ....................................................... 13

3.3. Regional nerve block of the caudal region in cattle ....................................................... 14

3.3.1. Caudal epidural anesthesia ........................................................................................... 14

3.3.2. Continuous caudal epidural anesthesia ......................................................................... 16

3.3.3. Internal pudendal nerve block ...................................................................................... 17

4. COMPLICATIONS AND SIDE EFFECTS OF REGIONAL ANESTHESIA .............. 19

4.1. Adverse reactions .............................................................................................................. 19

4.2. Over dosage ....................................................................................................................... 20

4.2.1. Treatment of over dosage toxicity of regional anesthesia ............................................ 20

5. CONCLUSIONS AND RECOMMENDATIONS ................................................................ 22

6. REFERENCES ........................................................................................................................ 24

III

LIST OF ABREVIATIONS

Cm Centimeter

CNS Central nervous system

Co1 First coccygeal vertebrae

Co2 Second coccygeal vertebrae

DOA Duration of action

Fig Figure

HCL Hydrochloride

Kg Kilogram

L1 First lumbar

L2 Second lumbar

L4 Fourth lumbar

L5 Fifth lumbar

Mg Milligram

Min Minute

Ml Milliliter

MOA Mechanism of action

S3 Third sacral

S4 Forth sacral

T13 Last thoracic vertebrae

% Percent

IV

LIST OF FIGURES

Fig.1: Needle placement for desensitizing the cornual nerve in cattle8

Fig.2: Needle placement for desensitizing the auriculopalpebral nerve in cattle9

Fig. 3: Retrobulbar needle placement through the medial canthus of the eye in cattle.11

Fig.4: Needle placement for the proximal paravertebral nerve block in cattle..13

Fig.5: Needle placement for the distal paravertebral nerve block in cattle14

Fig.6: Needle placement for caudal epidural anesthesia ..16

Fig.7: Needle placement for the internal pudendal nerve block ..18

Fig.8: Ischiorectal approach for the internal pudendal nerve block.18

V

LIST OF TABLES

Table 1: Properties of selected local anesthetic agents used in veterinary medicine5

Table 2: Summary on common local anesthetics used in veterinary clinic6

Table 3: Advantages and disadvantages of paravertebral nerve block techniques in cattle.14

VI

SUMMARY

Regional anesthesia or the nerve block is a form of anesthesia in which loss of sensation in a

region of the body is produced by application of local anesthetic agent to all the nerves supplying

that region, only a part of the body is anesthetized. Regional anesthetic techniques can be divided

into central and peripheral techniques. The central techniques include neuroaxial block. The

peripheral techniques can be further divided into plexus blocks such as brachial plexus blocks, and

single nerve blocks. The regional anesthesia can be achieved by peri neural injection as in nerve

blocks of head region, paravertebral block and epidural block by spinal injection. Many surgical

procedures can be performed safely and humanly in ruminants using a combination of physical

restraint, mild sedation and regional anesthesia. Successful regional anesthesia requires a thorough

knowledge of the anatomy of the nerve(s), including the structures they innervate, their location and

relationship to other structures such as arteries, veins and facial layers. This article describes the

approach to regional anesthesia and discusses the anatomical considerations which need to be taken

into account when performing these procedures. In regional anesthesia; anesthesiologist injects

medication near a cluster of nerves to anesthetize only the area of the body that requires surgery.

The patient may remain awake or may be given a sedative. Spinal and epidural blocks involve

interrupting sensation from the legs or abdomen by injecting local anesthetic in or near the spinal

canal.

Key words: Cattle, Nerve block, Regional anesthesia,

1

1. INTRODUCTION

Regional anesthesia is applying local anesthetic around the nerves supplying a specific region,

without loss of consciousness. It is brought about by blocking conduction in sensory nerve or

nerves innervating the region where an operation is to be performed. Regional analgesia can be

done by peri neural injection and spinal block (Barrie, 2001).

Many surgical procedures can be performed safely and humanly in cattle using a combination of

physical restraint, mild sedation, and regional anesthesia. Regional anesthetic techniques are

usually simple, inexpensive, and provide a reversible loss of sensation to a relatively well-

defined region of the body (Stats, 2000).

Before regional anesthesia is performed, the animal should be adequately restrained. The type of

restraint used depends on the temperament of the animal and the anesthetic technique to be used.

Sedation may be necessary, however, in some cases. The site of injection should be prepared by

clipping or shaving the hair and scrubbing and disinfecting the skin. Regional anesthesia

involves the anesthesia of an area of the body without necessarily affecting the patients level of

consciousness (Kumar, 1996).

In addition to its benefit, regional anesthesia has the risks and complications associated with use

of local anesthetics, the risks and complications of using needles and drugs in the proximity of

nerves such as neuropraxia and those risks associated with a particular technique. As with any

other anesthetic technique, choosing regional anesthesia requires a thorough assessment that

should include the patient, the surgeon, the nature of the procedure and its estimated duration as

well as the level of experience of the anesthesiologist with regional anesthesia and its

management (Susan et al., 2004).

Regional anesthesia is the first choice of anesthesia in ruminants since general anesthesia has

certain limitations, anatomical and physiological peculiarities. In ruminants, flank region is the

most common site for any laparotomy; caesarian section, rumenotomy, intestinal obstruction,

volvulus, ruminal fistula, foreign body syndrome and hernia (Lee, 2006; Kumar, 2003). This

region is innervated by the last thoracic (T13), first lumbar (L1) and second lumbar (L2) spinal

nerves (Lee, 2006).

2

During regional anesthesia of the flank region, nerves innervated to that region are blocked

through injection of local anesthetic as they emerge from the vertebral canal through the

intervertebral foramina in proximal paravertebral nerve block or more distally at free ends of the

lumbar transverse process and posterior border of the head of the last rib during distal

paravertebral nerve block (Kumar, 2003).

Paravertebral nerve block results effective analgesia in all layers of the abdominal wall. Regional

nerve blocks are temporary blocking of pathway for passage of impulses by injecting local

anesthetic solution resulting in desensitization in the region (Tucker, 2010). As compared to

other anesthetic techniques, regional anesthesia has many advantages like safe, easy in field

application, less toxicity in the body due to small quantity of the local anesthetic, produce

uniform analgesia of the site and there is normal healing in all systems in cattle (Duke and

Caulket, 2008).

Therefore the objectives of this seminar paper are:

o To review the most commonly used veterinary local anesthetic agents which plays

important role for regional nerve block in cattle

o To review the regional anesthesia technique in cattle

o To familiarize the regional anesthesia techniques among veterinarians

o To popularize the most common side effect of anesthetic agents in cattle

3

2. LITRATURE REVIEW ON REGIONAL ANESHESIA IN CATTLE

2.1. Historical perspective of regional anesthesia in cattle

The History of Veterinary anesthesia is reviewed from the time of the discovery of the anesthetic

properties of ether in birds in the 16th century to its first recorded use in humans and then in

domestic animals in 1846 (Hall and Trim, 2000).

Regional anesthesia, the art of rendering a part of the body insensible for an operation, traces its

roots to Karl Keller of Vienna, who, in 1884, demonstrated the use of topical anesthesia on the

eye. However, regional anesthesia would not have progressed much beyond topical application

and thereafter many pioneers tried new and different ways of producing regional insensibility. In

the 1940s regional anesthesia of the flank of the cattle was reported. In many ways, the history

of techniques in regional anesthesia mirrors the way in which scientific knowledge is obtained:

It is an intellectual history of ideas (OConnor, 2005).

The history of spinal anesthesia demonstrates the cyclical nature of regional anesthetic

techniques. In 1885 in the United Kingdom is credited with the introduction of conduction

anesthesia through hypodermic injection (Krommendijk et al., 1999).

In 1891, von Ziemssen, a German physician whose main medical interest was infectious disease,

reported on the feasibility of injecting drugs by means of a lumbar puncture (Noordsy and Ames,

2006).

The use of regional anesthetic techniques in animals started near the turn of the twentieth

century. In 1901, the use of regional anesthesia is intellectually challenging and incredibly

rewarding. The list of indications for regional anesthesia continues to expand as the number of

regional techniques expands or is improved upon to allow more peripheral techniques to be

performed (Shuttlworth and Smith, 2000).

Decreases in morbidity and mortality, improved postoperative pain control and decreases in

perioperative complications have been listed as potential benefits of regional anesthesia in cattle

(Katta et al., 2000 and Stevenson, 2006). In 1908, Bier introduces the IV block (Bier block) with

procaine. In 1911 Herschel performs the first percutaneous axillary block and in 1911

Kulenkampff performs the first percutaneous supraclavicular block (Hall and Trim, 2000).

4

2.2. Local anesthetics

There are many local anesthetics that vary in their potency, toxicity, and cost. A short acting

local anesthetic procaine hydrochloride was first introduced for local and regional anesthesia but

because of adverse CNS and cardiovascular effects and apnea the use is discouraged (Skara,

2003).

Some of local anesthetics that are commonly used for regional anesthesia in veterinary use:

A. Procaine(short acting)

It has slower onset of action, and spreads less well compared to lidocaine. The unique

ability of procaine to cause dose-dependent methemoglobinemia limits its clinical

usefulness. It is not commonly use in cattle as it causes swelling around the block. By

this reason great accuracy is needed when doing specific nerve block (Rosenberg,

2002).

B. Lidocaine(intermediate action)

This is the most widely used general-purpose local anesthetic in veterinary use. It possesses

reasonably rapid onset of action, with good spreading properties, being a good all round useful

local anesthetic. Duration of action is variable (depending on uptake) but will be around 1 hour

without epinephrine, and 2 hours with epinephrine (Dan, 1993).

C. Mepivacaine(intermediate action)

This is the most widely used drug in the horse as it causes very little swelling and edema in the

area of injection, possibly as it lacks vasodilatory action. Onset of action is faster and reliability

of block greater than with procaine (Streis et al., 1991).

D. Bupivacaine(long acting)

This drug has a prolonged duration of action; up to eight hours when combined with

epinephrine. It is therefore used whenever long action is required as such in post-operative

analgesia and prolonged surgery (White, 1985).

5

Table 1: properties of selected local anesthetic agents used in veterinary medicine

Trade Name Class potency Lipid

Solu

bility

Protein

Binding

Onset of Effect

(min)

Duration

(min)

Procaine (Novocaine) Ester 1 6% Slow (30-40) 6090

Chloroprocaine

(Nesacaine)

Ester 1 1 7% Fast (10-15) 3060

Lidocaine (Xylocaine) Amide 2 3.6 65% Fast (10-20) 90200

Mepivacaine (Carbocaine) Amide 2 2 75% Fast (10-20) 120240

Bupivacaine (Marcaine) Amide 8 30 95% Intermediate

(15-30)

180600

Tetracaine (Pontocaine) Ester 8 80 80% Slow (30-40) 180600

Source: (Stoelting, 1999)

6

Table 2: summary on some local anesthetics used in veterinary clinic

Drug

class

MOA

DOA

Effect

Adverse

Bupivacai

ne

(Marcaine

)0.5%

Local

anesthetic

agent

(amide )

Blocks nerve transmission

by blocking Na channel and

preventing excitation

conduction

Process

46 hr; (epidural,

local

infiltration)

Reversible

prevention of

nerve

transmission;

thus motor,

sensory, and

autonomic

function is

temporarily

inhibited

CNS excitation,

seizures, respiratory

paralysis, hypotension,

hypothermia,

ventricular

arrhythmias

Lidocaine

(Xylocain

e**): 2.0%

Local

anesthetic

agent

(amide)

Blocks sodium influx and thus

prevents nerve depolarization

and conduction

90200 min; (epidural, local

infiltration)

Blocks pain,

motor, and

sympathetic

fibers; also used

IV to treat

ventricular

arrhythmias

Hypotension due to

vasodilation;

respiratory

arrest is possible when

given epidurally;

seizures at high doses

Mepivacai

ne(Carboc

aine-V):

12%

Local

anesthetic

agent

(amide)

Blocks sodium influx and thus

prevents nerve depolarization

and conduction

120240 min; (epidural, local

infiltration)

Blocks pain, motor

and sympathetic

fibers

Hypotension due to

vasodilation and

respiratory

arrest are possible

when given

epidurally; seizures

and cardio toxicity

with overdose

Procaine

(Novocain

e)

Local

anesthetic

(ester

linked)

Blocks sodium influx and thus

prevents nerve depolarization

and conduction

6090 min; (local

infiltration)

Blocks pain,

motor, and

sympathetic

fibers

May cause allergic

reaction

Source: (Duke and Caulket, 2008)

7

3. REGIONAL NERVE BLOCK AND ITS TECHNIQUE IN CATTLE

Rules of performing regional or local analgesia: Clip hair and surgically prepare site, use sterile

needles, syringes and anesthetic solution, unless otherwise stated, always aspirate and check for

blood before injection. Note the location of blood vessels that lie in close proximity to target

nerves, always work out the toxic dose for the patient and stay below, base total dose

calculations on lean bodyweight, not on actual bodyweight, identify key anatomical landmarks

(Barrie, 2001).

3.1. Regional nerve block of head

3.1.1. Cornual nerve block

Cornual nerve is a sensory nerve supplying to the horn core and skin around its base. Cornual

nerve is a branch of lacrimal nerve which is a division of the ophthalmic branch of trigeminal

nerve. The cornual nerve emerges behind the orbit and ascends along frontal crest and placed

relatively superficial in the upper third covered by skin and the thin layer of frontalis muscle.

The caudal part of the nerve is having close association with the superficial temporal artery

(Stafford and Mellor, 2005).

The cornual nerve block is used for desensitizing horn core in cattle. The horn and the skin

around the base of the horn are innervated by the corneal branch of the lacrimal or

zygomatoaticotemporal nerve, which is part of the ophthalmic division of the trigeminal nerve.

The cornual nerve passes through the periorbital tissues dorsally and runs along the frontal crest

to the base of the horns (Edwards, 2001).

Indication: Analgesia of the horn core and skin around the base of the horn mainly for dehorning

process. Dehorning, or disbudding, is the process of removing or stopping the growth of

the horns of livestock (Venugoplan, 2000).

Site of block: Local anesthetic is deposited subcutaneously and relatively superficially midway

between the base of the horn and lateral canthus of the eye, at the inferiolateral border of the

frontal crest where the nerve is superficial. Lidocaine 2% is commonly used (Edwards, 2001).

Dosage: Approximately 2 to 5 ml of (1 to 3ml in calves) lidocaine in adult is deposited

subcutaneously. Complete anesthesia may take 10 minutes. Larger cattle with well-developed

8

horns require additional anesthetic infiltration along the caudal aspect of the horn, in the form of

a partial ring block, to desensitize subcutaneous branches of the second cervical nerve (Elmore,

1980).

Fig. 1: Needle placement for desensitizing the cornual nerve in cattle (Edwards, 2001).

Technique of corneal block: Insert a 2.5 cm, 20 gauge needle into the upper third of the temporal

ridge, immediately behind the ridge and about 2.5 cm below the base of the horn, to a depth of

0.7 to 1.0 cm. The nerve may be palpable, between the frontalis and temporal muscles, about

half way from the lateral canthus of the eye to a point about 3cm below the lateral base of the

horn (Misty et al., 2008). In large bulls the needle should be inserted to about 2.5 cm deep. Draw

back on the plunger to check that the needle is not placed intravascularly. Inject 5 to 10 ml

lidocaine 2% hydrochloride (Scott et al., 1993). A blink response should be noted during

administration; drooping of the upper eyelid is a good early sign of correct anesthesia. Failure

may occur if the anesthetic solution is injected too deeply, into the temporal muscle aponeurosis.

Note: In large individuals with well developed horns make a second injection about 1 cm caudal

to the first injection, to block the posterior division of the nerve (Sharma, 2005).

3.1.2. Auriculopalpebral nerve bock

Anatomy: The eyelids are innervated by the auriculopalpebral nerve. The nerve is a motor

branch of facial nerve supplying to the orbicularis occuli muscle of the eye lid and therefore the

block produces akinesia only. It is mostly used in large animals for examination of eye, in

blepharospasm and for removal of foreign bodies. The nerve runs from the base of the ear along

the facial crest, past and ventral of the eye giving of its branchs on the way. Auriculopalpebral

nerve supplies to the orbicularis occuli muscles it is the one of the branches of facial nerve and

motor to eyelid and auricular muscle (Stafford and Mellor, 2005).

Indications: Surgical affection related to eyelid (entropion, ectropion and prolapse of 3rd

eyelid), to avoid the blinking reflex of the eye lid to examine and treat the eye, to relieve the

9

spasm of the eye lids following injury, to use in conjunction with Petersons block, during

surgical treatment of squamous cell carcinoma of eye removal of foreign body from cornea and

subconjunctival injections (Sakarda, 2006).

Site of block: Anesthesia of the eyelid is accomplished by performing a line block of the eyelid

or by blocking the auriculopalpebral branch of the facial nerve. The site is directly at appoint

midway between the imaginary line drown from the lateral canthus of the eye and the temporal

fossa (Navarre and Numbing, 2006).

Technique: Regional analgesia techniques are necessary for surgery of the eye and its associated

structures. In bovine a 20 -or 22- gauge,3-5 cm long needle is inserted subcutaneously at a point

midway between the imaginary line drown from the lateral canthus of the eye and the temporal

fossa and inject 3-5 ml of 2% Lidocaine is injected subfacialy (Sakarda ,2003).

Fig.2: Needle placement for desensitizing the auriculopalpebral nerve in cattle (Sakarda, 2003).

3.1.3. Retrobulbar nerve block

This block provides kinesis of the extraocular muscles by blocking cranial nerves II, III, and VI,

by preventing movement of the globe. It is indicated for enucleating of the eye or for surgery of

the cornea. The needle placement for retrobulbar injection is the midway between medial and

lateral canthus of eye or the upper and lower eyelids (Scott et al., 1993).

Technique:

I. Four-point retrobulbar nerve block

The four-point retrobulbar block is technically easier and can be done more rapidly as compared

with the Peterson eye block. In this technique, an 18 gauge, 9-cm long needle is introduced

through the skin on the dorsal, lateral, ventral and medial aspects of the eye, at 12, 3, 6, and 9

oclock positions, respectively. Introduction of the needle through the conjunctiva should be

avoided to reduce the occurrence of ocular contamination. The needle is directed behind the

10

globe using the bony orbit as a guide. When the needle is introduced into retrobulbar sheath, the

eye will move slightly with the tug of the needle. The surgeons finger is used to deflect the

globe to protect it from the point of the needle. After this location is reached and aspiration is

performed to assure that the needle is not in a vessel, 5-10 milliliters of lidocaine (2%) is

deposited at each site. Mydriasis indicates a successful block (Sharma, 2005).

II. The single retrobulbar block:

It is an alternative to the four-point retrobulbar block. In this technique, the 9-cm long 18-gauge

needle is bent into a circle. The needle is inserted immediately ventral to the dorsal orbital rim

and directed such that the needle impacts into the bone of the orbit. Then the needle is advanced

as it is rotated ventrally in a progressive manner such that the needle remains in close proximity

to the bone. After the needle is inserted to the caudal aspect of the eye, 20 ml of 2% lidocaine

HCL is administered after aspiration to ensure that the needle is not positioned in a vessel or

other fluid structure. Successful deposition of lidocaine causes mild apoptosis of the globe

(Riebold et al., 1982).

Fig.3: Retrobulbar needle placement through the medial canthus of the eye in cattle (Riebold et

al., 1982).

3.1.4. Peterson nerve block in cattle

Indication: To abolish eye ball movement as well as the blinking reflex of the eye lids. It is used

for enucleating of the eye or for surgery of the cornea, and when properly performed causes

analgesia of the cornea, Mydriasis and apoptosis (Edwards, 2001).

It involves less risk in damaging surrounding anatomic structure around the eye globe, and less

volume requirement reducing potential for systemic toxicity and expense. Oculomotor, trochlear,

abducent, and three branches of the trigeminal nerve which are responsible for sensory and

motor function of all structures of the eye except the eyelid, are desensitized in 10 15 minutes

11

following injection. Adequate restraint of the head is necessary when performing this procedure

(Sharma, 2005).

Site of injection: The point of injection is the notches formed by the supraorbital process

cranially, the zygomatic arch ventrally, and the coronoid process of the mandible caudally.

Approximately 15 ml of 2% lidocaine is injected (Sakarda, 2006).

Technique of Peterson nerve block: After performing a small local skin block over the intended

site of puncture a 3.8-cm long 14 gauge needle is inserted through the skin as a cannula for

introduction of an 18-gauge 9-cm long needle for the nerve block. The cannula is inserted caudal

to the junction of the supraorbital process and zygomatic arch and is introduced through the skin.

Then, the 18-gauge, 9-cmlong needle is introduced through the cannula needle and is directed in

a horizontal and slightly dorsal direction until the coronoid process is encountered (Getty, 1995).

The needle is walked off the rostral aspect of the coronoid process and advanced in a

ventromedial direction along the caudal aspect of the orbit until the needle encounters the bony

plate encasing the foramen orbitorotundum. Once the needle is advanced to the foramen, it is

advised that the needle be drawn back a few millimeters to reduce the risk of intrameningeal

injection. After aspirating to assure the needle is not in the internal maxillary artery, 10-15

milliliters of lidocaine (2%) is deposited, with an additional 5 milliliters of lidocaine deposited

as the needle is slowly withdrawn. Mydriasis indicates a successful block (Misty, 2008).

3.2. Regional nerve bock of trunk of cattle

Indications: It is commonly used for such procedures as surgery of the digestive tract

(abomasopexy, omentopexy, rumenotomy, volvulus, and so forth), cesarean section,

ovariectomy and liver and kidney biopsy. The most commonly used techniques are proximal

paravertebral block (farguharsonsmethod), distal paravertebral block (Magda technique). The

first two are most commonly used techniques (Paulb and Jeennings, 1984).

3.2.1. Proximal paravertebral nerve block (Farguharsons method)

The proximal paravertebral nerve block desensitizes the dorsal and ventral nerve roots of the last

thoracic (T13) and first and second lumbar (L1 and L2) spinal nerves as they emerge from the

intervertebral foramina (Kumar, 2003).Approach to the Site of proximal paravertebral nerve

12

block: For T13, just cranial to the transverse process of L1; for L1, just cranial to the transverse

process of L2; For L2, just cranial to the transverse process of L3 (Roe, 1986).

Technique:

To perform proximal paravertebral block ,Proper needle placement of anesthetic, the skin at the

cranial edges of the transverse processes of L1, L2, and L3, and at a point 2.5 to 5 cm of the

dorsal midline can desensitized by injecting 2 to 3 ml 2% lignocaine using an 18- gauge 2.5-cm

needle is necessary. A 14-gauge 2.5-cm needle is used as a cannula or guide needle to minimize

skin resistance during insertion of an 18-gauge 10- to 15-cm spinal needle. Approximately 5 ml

of regional anesthetic may be placed through the cannula to anesthetize further the tract for

needle placement (Cakala, 2009).

To desensitize T13, the cannula needle is placed through the skin at the anterior edge of the

transverse process of L1 at approximately 4 to 5 cm lateral to the dorsal midline. The 18-gauge

10- to 15-cm spinal needle is passed ventrally until it contacts the transverse process of L1 to

desensitize L1 and L2; the needle is inserted just caudal to the transverse processes of L1 and L2

(Venugopalan, 2000). The needle is walked off of the caudal edges of the transverse processes of

L1 and L2, at a depth similar to the injection site for T13, and advanced approximately 1 cm to

pass slightly ventral to the process and into the inter-transverse ligament. For rumenotomy

blocking T13, L1 and L2 nerve is sufficient. For caesarean section L3 nerve should be blocked

(Noordsy and Ames, 2006).

Fig.4: Needle placement for the proximal paravertebral nerve block in cattle.

L1, first lumbar vertebra; L5, fifth lumber vertebra; R13, last rib; T13, last thoracic vertebra

(Noordsy and Ames , 2006).

13

3.2.2. Distal paravertebral nerve block (Magda method)

Site of nerve block: In this technique the needle enters ventral to the tips of the transverse of

the L1, L2 and L4 lumbar vertebrae. The distal paravertebral nerve block desensitizes the dorsal

and ventral rami of the spinal nerves T13, L1, and L2 at the distal ends of the transverse

Processes of L1, L2, and L4, respectively. 10 ml 2% Lignocaine is injected to desensitize the

region (Susan et al., 2004).

Technique: An 18-gauge 3.5- to 5.5-cm needle is inserted ventral to the transverse process

lumbar vertebrae and local anesthetic is infused in a fan-shaped pattern. The needle can then be

removed completely and reinserted or redirected dorsally, in a caudal direction, where 2 to 3 ml

of anesthetic agent is again infused in a fan-shaped pattern. This procedure is repeated for the

transverse processes of the second and forth lumbar vertebrae (Venugoplan, 2000).

Fig.5: Needle placement for the distal paravertebral nerve block in cattle (Skarda, 2006).

14

Table 3: Advantages and disadvantages of paravertebral nerve block techniques in cattle

Techniques Advantages Disadvantages

Proximal

Paravertebral

Block

Small dose of analgesic,

Wide and uniform area of analgesia and

muscle relaxation,

Minimal intra-abdominal pressure

Increased intestinal tone and motility

Absence of local analgesic from the

operative wound margins

Technical difficulty

Arching up of the spine due to

paralysis of the back muscles.

Risk of penetrating vital

structures such as the aorta and

thoracic longitudinal vein on the

left side and the caudal Vena

cava on the right side.

Distal

Paravertebral

Block

The use of more routine size needles, no risk

of penetrating a major blood vessel.

Lack of scoliosis minimal weakness in the

pelvic limb and Ataxia.

Larger doses of

anesthetic are needed.

Variation in efficiency

exists, particularly if

the nerves vary in their

anatomical pathway.

Source: (Lee, 2006)

3.3. Regional nerve block of the caudal region in cattle

3.3.1. Caudal epidural anesthesia

When the anesthesia is injected within the canal but outside the durra matter, it is called epidural

anesthesia. In epidural anesthesia there is desensitization of the first sensory nerves followed by

sacral, parasympathetic, sympathetic and motor nerves (Krames, 2000).

Depending on the site of injection epidural anesthesia can be caudal epidural anesthesia,

lumbosacral epidural anesthesia and lumbar segmental epidural anesthesia. Out of these

techniques the most commonly followed is the caudal epidural anesthesia (Oconnor, 2005).

It mostly produces the desensitization of sacral region, tail, anus, vulva perineum, and caudal

aspect of the femoral region. It doesnt affect the motor response of hind limb. In this the needle

enters the spinal canal but doesnt penetrate menings and the injected solution penetrates along

15

the canal outside the durra matter. Caudal epidural anesthesia is an easy and inexpensive method

of analgesia that is commonly used in cattle (Navarre and Numbing, 2006).

Indications: Prolapsed of vagina, uterus and rectum, treatment of parturient paresis, rectovaginal

fistula operation, repair of perianal fistula, correction of atresia ani, prevention of straining,

amputation of rectum and tail. The site is in the fossa between the last sacral vertebra and the

first coccygeal vertebra or between the first and second coccygeal vertebrae. We commonly use

2% lidocaine HCL (approximately 1 ml/kg), bupivacaine HCL with adrenaline@ 0.01ml/kg and

xylaxine HCL 0.02 0.04 mg/kg+ 0.5 % lignocaine (Mark and Papi, 2007).

Technique: If possible the hair should be clipped and the skin scrubbed and disinfected. Standing

alongside the cow, the tail should be moved up and down to locate the fossa between the last

sacral vertebra and the first coccygeal vertebra or between the first and second coccygeal

vertebrae (Misty et al, 2008 ), an 18-gauge 3.8-cm needle, with no syringe attached, is directed

perpendicular to the skin surface, then the needle is pushed down till it contacts the floor the

vertebral canal, fit the syringe and withdraw the piston slightly to check the presence of blood .If

blood is present, the meddle is taken out, blood clot cleaned and reinserted, lignocaine solution

3-5 ml is injected. If the needle is in correct position there is practically no resistance felt during

injection. If resistance felt, slightly adjust the needle and then inject. Onset of effect is seen,

within few minutes, by flaccidity of the tail. Repeated injection may be used for longer action

(Rawal et al., 2009).

Fig.6. Needle placement for caudal epidural anesthesia (A) and for continuous caudal epidural

anesthesia (B) located between the first and second coccygeal vertebrae (Rawal et al., 2009).

16

The advantages of caudal epidural anesthesia are rapid recovery, simple and inexpensive, little

effect on organ systems and good muscle relaxation and postoperative analgesia. In addition to

its advantage it has some complications such as permanently paralyzed tail, loss of motor control

of hind limb (ataxia) and infection resulting in draining tracts at the site (Horlocker et al., 2009).

Continuous caudal epidural anesthesia is used in cattle with chronic rectal and vaginal prolapse

that experience continuous straining after the initial epidural. This procedure is performed by

placing a catheter into the epidural (Navarre and Numbing, 2006).

3.3.2. Continuous caudal epidural anesthesia

Indication: Continuous caudal epidural anesthesia is used in cattle with chronic rectal and

vaginal Prolapse that experience continuous straining after the initial epidural (Noordsy and

Ames, 2006).

Anesthetic of choice: More recently, a 2-agonists and opioids either alone or in combination

with local anesthetic solutions have been used for epidural anesthesia. Epidural administration of

the a2-agonist xylazine hydrochloride (0.05 mg/kg) diluted in 5 to 12 ml of sterile saline or

xylazine hydrochloride (0.3 mg/kg) added to 5 ml of 2% lidocaine hydrochloride combinations

offer similar anesthesia to lidocaine. Although the duration of anesthesia is prolonged (45

hours) using these combinations, systemic effects (sedation, salivation, and ataxia) may also

occur (Hall and Trim, 2000).

Technique of Continuous caudal epidural anesthesia:

This procedure is performed by placing a catheter into the epidural space for intermittent

administration of local anesthetic. A 17-gauge 5-cm spinal needle (touchy needle) with stylet in

place is inserted into the epidural space at Co1 to Co2 with the bevel directed craniad. The stylet

is removed, and 2 ml of local anesthetic is injected to determine if the needle is in the epidural

space. A catheter is inserted into the needle and advanced cranially for 2 to 4 cm beyond the

needle tip. The needle is then withdrawn while the catheter remains in place. An adapter is

placed on the end of the catheter and the catheter secured to the skin on the dorsum. Local

anesthetic solution may then be administered as needed (Rawal et al, 2009).

17

3.3.3. Internal pudendal nerve block

Anatomy: The internal pudendal nerve consists of fibers originating from the ventral branches of

the third and fourth sacral nerves (S3 and S4) and the pelvic splanchnic nerves (Constantinescu,

2001).

Indications: To facilitate relaxation of the bulls penis without causing locomotors impairment,

the internal pudendal nerve block can be used in the standing bull for penile relaxation and

analgesia distal to the sigmoid flexure and examination of the penis, in the standing female the

internal pudendal nerve block can be used to relieve straining caused by chronic vaginal prolapse

and this may also be used for surgical procedures of the penis, such as repair of prolapses,

removal of perianal tumors, removal of penile papillomas or warts, and other minor surgeries of

the penis and prepuce (Elmore, 1980).

Technique or procedure:

The procedure for bilateral internal pudendal nerve block was first described by Larson. This

procedure involves desensitizing the internal pudendal nerve and the anastomotic branch of the

middle hemorrhoidal nerve using an ischiorectal approach (Larson, 2001).

The skin at the ischiorectal fossa on either side of the spine is clipped, disinfected, and

desensitized with approximately 20 ml 2% lidocaine. A 14-gauge 1.25-cm needle is inserted

through the desensitized skin at the ischiorectal fossa to serve as a cannula. An 18-gauge 10-cm

spinal needle is then directed through the cannula to the pudendal nerve. The operators left hand

is placed into the rectum to the level of the wrist and the fingers directed laterally and ventrally

to identify the lesser sacroisciatic foramen. The lesser sciatic foramen is first identified by rectal

palpation as a soft depression in the sacroisciatic ligament (Scott et al., 1993).

The internal pudendal nerve can be readily identified lying on the ligament immediately cranial

and dorsal to the foramen and approximately one fingers width dorsal to the pudendal artery

passing through the foramen. The internal pudendal artery can be readily palpated a fingers

width ventral to the nerve. The spinal needle is held in the operators right hand and introduced

through the cannula in the ischiorectal fossa. The spinal needle is directed medial to the

sacroisciatic ligament and directed cranioventrally (Edwards, 2001).

18

The needle is not felt until it has been introduced approximately 5 to 7 cm and can then be

repositioned to the nerve. Once at the pudendal nerve, 20 ml lidocaine is deposited at the nerve.

The needle is then partially withdrawn and redirected 2 to 3 cm more caudodorsally where an

additional 10 ml of local anesthetic is deposited at the cranial aspect of the foramen to

desensitize the muscular branches and the middle hemorrhoidal nerve. The needle is then

removed and the sites of deposition are massaged to aid in dispersal of the local anesthetic. This

procedure is then repeated on the opposite side of the pelvis. Relaxation of the penis varies and

may take as long as 30 to 40 minutes for full effect. The duration of the internal pudendal nerve

block lasts from 2 to 4 hours (Larson, 2001).

Fig.7: Needle placement for the internal pudendal nerve block. (A) Internal pudendal nerve.

(B) Caudal rectal nerve. (C) Internal pudendal artery. (D) Sacroisciatic ligament

(Constantinescu, 2001).

Fig. 8: Ischiorectal approach for the internal pudendal nerve block. The injection site for the

internal pudendal nerve block in cattle is at the point in the ischiorectal fossa that is most deeply

depressed with the surgeons finger (Larson, 2001).

19

4. COMPLICATIONS AND SIDE EFFECTS OF REGIONAL ANESTHESIA

4.1. Adverse reactions

Systemic: Adverse experiences following the administration of lidocaine are similar in nature

to those observed with other amide local anesthetic agents. These adverse experiences are, in

general, dose-related and may result from high plasma levels caused by excessive dosage, rapid

absorption or inadvertent intravascular injection, or may result from a hypersensitivity,

idiosyncrasy or diminished tolerance on the part of the patient. Serious adverse experiences are

generally systemic in nature. The following types are the most commonly reported adverse

reactions (Lanza, 1996).Central Nervous System: CNS manifestations are excitatory and/or

depressant and may be characterized by lightheadedness, nervousness, apprehension, euphoria,

confusion, dizziness, drowsiness, tinnitus, blurred or double vision, vomiting, sensations of heat,

cold or numbness, twitching, tremors, convulsions, unconsciousness, respiratory depression and

arrest (Katta et al., 2000). The excitatory manifestations may be very brief or may not occur at

all, in which case the first manifestation of toxicity may be drowsiness merging into

unconsciousness and respiratory arrest. Drowsiness following the administration of lidocaine is

usually an early sign of a high blood level of the drug and may occur as a consequence of rapid

absorption (Cox et al., 2003).Cardiovascular System: Cardiovascular manifestations are

usually depressant and are characterized by bradycardia, hypotension, and cardiovascular

collapse, which may lead to cardiac arrest (Mather and Chang, 2001).

Allergic: Allergic reactions are characterized by cutaneous lesions, urticaria, edema or

anaphylactic reactions. Allergic reactions may occur as a result of sensitivity to local anesthetic

agents in multiple dose vials (Katta et al., 2000). Allergic reactions as a result of sensitivity to

lidocaine are extremely rare and, if they occur, should be managed by conventional means. The

detection of sensitivity by skin testing is of doubtful value (Milne, 2002).

Neurologic: The incidences of adverse reactions associated with the use of local anesthetics

may be related to the total dose of local anesthetic administered and are also dependent upon the

particular drug used, the route of administration and the physical status of the patient. In the

practice of caudal or lumbar epidural block, occasional unintentional penetration of the

20

subarachnoid space by the catheter may occur (Rosenberg, 2002). Subsequent adverse effects

may depend partially on the amount of drug administered subduraly. These may include spinal

block of varying magnitude, hypotension secondary to spinal block, loss of bladder and bowel

control, and loss of perineal sensation and sexual function (Katta et al., 2000). Persistent motor,

sensory and/or autonomic (sphincter control) deficit of some lower spinal segments with slow

recovery (several months) or incomplete recovery have been reported in rare instances when

caudal or lumbar epidural block has been attempted (Mather and Chang, 2001).

4.2. Over dosage

Acute emergencies from local anesthetics are generally related to high plasma levels

encountered during therapeutic use of local anesthetics (Misty et al., 2008).

Underventilation or apnea due to unintentional subarachnoid injection of local anesthetic

solution may produce these same signs and also lead to cardiac arrest if ventilatory support is not

instituted. Increasing the volume and concentration of lidocaine hydrochloride injection may

result in a more profound fall in blood pressure when used in epidural anesthesia (Mark and

Papi, 2007).

Although the incidence of side effects with lidocaine is quite low, caution should be exercised

when employing large volumes and concentrations, since the incidence of side effects is directly

proportional to the total dose of local anesthetic agent injected. Delay in proper management of

dose-related toxicity, underventilation from any cause and/or altered sensitivity may lead to the

development of acidosis, cardiac arrest and, possibly, death (Cox et al., 2003).

4.2.1. Treatment of over dosage toxicity of regional anesthesia

Atropine may be used to reverse bradycardia and hypotension. Doxapram may be used to

reverse respiratory depression. Alpha-2 receptor antagonists such as yohimbine, tolazoline and

atipamezole are specific antagonists to xylazine. At the first sign of underventilation or apnea,

oxygen should be administered (Payne et al., 1998).

If cardiac arrest should occur standard cardiopulmonary resuscitative measures should be

instituted. Dialysis is of negligible value in the treatment of acute over dosage with lidocaine In

21

case of accidental overdose leading to respiratory failure, cold water douches and artificial

respiration are indicated (Katta et al.,2000).

22

5. CONCLUSIONS AND RECOMMENDATIONS

In General regional anesthesia techniques are safe and effective methods for providing

anesthesia for common surgical procedures and painful conditions in cattle. These techniques are

inexpensive and easy to perform and offer safe alternative to general anesthesia in some cases.

Regional anesthetic techniques are easily employed in practice with knowledge of anatomy and

careful dose calculation, the various blocks can be carried out with good success.

For the majority of the techniques discussed, specialist equipment is not necessary, as they

require only items commonly found in practice. The use of regional anesthetic techniques can

greatly increase patient comfort both during anesthesia and in recovery. Regional anesthesia

techniques are usually selected to be carried out quickly, easily, cheaply and with inexpensive

equipment, the most suitable technique that can be easily followed under field conditions and to

be generally safe for the animals involved. Since the mid-1990s, many advances have been made

in the field of animal pain research but much remains to be done. It is necessary a full analysis of

matters that should be considered when deciding whether or not, and how, to undertake

particular painful husbandry procedures is increasing. This suggests that alternative approaches

must be considered.

In over all, the techniques of regional anesthesia require every anesthesiologist to properly apply

the method. The cornual nerve block is used for desensitizing horn core in cattle for dehorning

.Auriculopalpebral nerve bock is mostly used in large animals for examination of eye, in

blepharospasm and for removal of foreign bodies. Retrobulbar block is used for enucleation of

the eye or for surgery of the cornea. paravertebral nerve block used for rumenotomy Caudal

epidural anesthesia mostly used for prolapsed of vagina, uterus and rectum, treatment of

parturient paresis, rectovaginal fistula operation, repair of perianal fistula, correction of Artesia

ani, prevention of straining, amputation of rectum and tail. Continuous caudal epidural

anesthesia is used in cattle with chronic rectal and vaginal prolapse that experience continuous

straining. Internal pudendal nerve block can be used in the standing bull for penile relaxation

and analgesia distal to the sigmoid flexure and examination of the penis, in the standing female

the internal pudendal nerve block can be used to relieve straining caused by chronic vaginal

prolapse and this may also be used for surgical procedures of the penis, such as repair of

prolapses, removal of perianal tumors, removal of penile papillomas or warts, and other minor

surgeries of the penis and prepuce.

23

Based on the above conclusions the following recommendations are forwarded:

Regional anesthesia injection for nerve block should be employed only by clinicians

who are well versed in diagnosis and management of dose-related toxicity and other

acute emergencies that might arise from the block.

The clinicians must ensure the immediate availability of oxygen, other resuscitative

drugs, cardiopulmonary equipment, and the personnel needed for proper management of

toxic reactions and related emergencies that might arise from the block.

The safety and effectiveness of the anesthetic agent should maintain through proper

dosage, correct technique, adequate precautions, and readiness for emergencies.

Standard textbooks should be consulted for specific techniques and precautions for

various regional anesthetic procedures.

The aseptic precautions are to be strictly adopted for nerve blocks.

Always use as low anesthetic as possible, as low concentration as possible and as low

gauge needle as possible for infiltration.

The selection of anesthetic should be based on the need. For short procedures Procaine

HCL, medium procedures Lignocaine HCL and long procedures Bupivacaine HCL are

ideal.

Local anesthetics may be used in the field of pain management especially continuous

epidural administration.

24

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ACKNOWLEDGMENTSTABLE OF CONTENTS3.1. Regional nerve block of head.7

LIST OF TABLESSUMMARY1. INTRODUCTION2. LITRATURE REVIEW ON REGIONAL ANESHESIA IN CATTLE2.1. Historical perspective of regional anesthesia in cattle2.2. Local anestheticsThere are many local anesthetics that vary in their potency, toxicity, and cost. A short acting local anesthetic procaine hydrochloride was first introduced for local and regional anesthesia but because of adverse CNS and cardiovascular effects and ap...Some of local anesthetics that are commonly used for regional anesthesia in veterinary use:

3. REGIONAL NERVE BLOCK AND ITS TECHNIQUE IN CATTLE3.1. Regional nerve block of head3.1.1. Cornual nerve block

Fig. 1: Needle placement for desensitizing the cornual nerve in cattle (Edwards, 2001).3.1.2. Auriculopalpebral nerve bock

Fig.2: Needle placement for desensitizing the auriculopalpebral nerve in cattle (Sakarda, 2003).3.1.3. Retrobulbar nerve blockThis block provides kinesis of the extraocular muscles by blocking cranial nerves II, III, and VI, by preventing movement of the globe. It is indicated for enucleating of the eye or for surgery of the cornea. The needle placement for retrobulbar injec...Technique:

Fig.3: Retrobulbar needle placement through the medial canthus of the eye in cattle (Riebold et al., 1982).3.1.4. Peterson nerve block in cattle3.2. Regional nerve bock of trunk of cattle3.2.1. Proximal paravertebral nerve block (Farguharsons method)

Fig.4: Needle placement for the proximal paravertebral nerve block in cattle.3.2.2. Distal paravertebral nerve block (Magda method)3.3. Regional nerve block of the caudal region in cattle3.3.1. Caudal epidural anesthesia

3.3.2. Continuous caudal epidural anesthesiaTechnique of Continuous caudal epidural anesthesia:3.3.3. Internal pudendal nerve block

4. COMPLICATIONS AND SIDE EFFECTS OF REGIONAL ANESTHESIA4.1. Adverse reactions4.2. Over dosage4.2.1. Treatment of over dosage toxicity of regional anesthesia

5. CONCLUSIONS AND RECOMMENDATIONS6. REFERENCES