Chapter 73 - Diagnostic and Regional anesthesia Flashcards
Mechanism of action of pain stimuli caused by an injury is transmitted to the CNS by peripheralnerves which ones?
myelinated A-δ- responsible for conduction of fast,sharp pain.
unonmyelinated C-fibers fordull, diffuse pain.
The majority of fibers concerned with nociceptive transmission are
C fibers
There are ≠ types of C-fibers mediate only:
pain
temperature
touch mediate only pain
and others mediate temperature + touch+ pain
How do LA work?
Local anesthetics (LA) block nerve conduction by preventing the increase in membrane permeability to sodium ions that occurs when nerves are stimulated.
The order and degree of neural blockade correlate with 3 factors name them
diameter
type of nerve fiber
degree of myelination
What are the first nerve fibers to block?
the 1st nerve fibers blocked are:
the B-fibers –> next the A-δ- and C-fibers -> last nerve fibers blocked are A-γ-, A-β-, and A-α3-fibers.
According to Weir and Strichartz development of blockade is:
sympathetic function 1st –> pin-pricksensation (touch Tº) –> motorfunction
Where does LA first diffuse when finds the nerve ?
As a LA diffuses into a nerve, it affects the fibers at its periphery 1st and those at its core last.
Name the different drugs for local anesthesia and time of action
Lidocaine 30 minutes to 3 hours
Mepivacaine from 90 minutes to 3 hours Bupivacaine from 3 to 8 hours
Ropivacaine reliably ameliorated lameness for 3hours
Liposomal bupivacaine approved in the USA for woundinfiltration in humans produced an anesthetic effect greater than 24 hours when used for a peripheral nerve block à good for standing surgery?
refregeration is contra-indicated why?
Inactivates methylparaben = prevention of bacterial growth
What can be added to LA to increase duration? what dose?
Epinephrine can be added o LA to increase the duration of LA +intensityDose epine 5 µg/mL0,1 mL of 1:1000 epine is added to 20 mL of LA = 1:200000 []Commercialy available LA with epine are less potent than the ones preparedin the hour.
What are the risks of adding epinephrine to lido?
Risks: necrosis of skin at injection site + white hair +tissue swelling
Describe palmar digital nerve block
volume of** 1.5 mL** (2 mL for very large horses) local anesthetic solution is deposited subcutaneously at the proximal border of the collateral cartilages
what does the block a branch of the palmar digital nerve, the ramus tori digitalis (ramus pulvinus) does?
result in selective desensitization of the navicular apparatus without loss of skin sensation in the heel region of the foot.
HOW? a needle is inserted immediately proximal and axial to the proximal margin of the collateral cartilage, **midway **between the palmar border of the DDFT and the palmar extent of the collateral cartilage, and is directed **parallel to the slope of the dorsal hoof wall **and the long axis of the digit.
Local anesthetic solution (2–2.5 mL) is injected on the axial side of each collateral cartilage
Low 4-Point Nerve Block
palmar metacarpal nerves are blocked by depositing 1 mL local anesthetic solution at the palmar surface of MCIII by inserting a needle distal to the button at the distal aspect of the second and fourth metacarpal (MCII and MCIV) (splint) bones
The palmar nerves are blocked by inserting the needle in a proximodistal direction, not too deeply so as to avoid entering the digital flexor tendon sheath inadvertently, and advancing the needle parallel with the skin in the** groove separating the SL and the DDFT total of 2 mL** of local anesthetic solution is deposited
Describe abaxial sesamoid nerve block
needle is inserted over each palpable nerve at the abaxial border of the proximal sesamoid bones and directed distally until the tip of the needle is level with the base of the proximal sesamoid bone
2 mL
High 4-Point Nerve Block
medial and lateral palmar nerves are generally blocked subfascially with the limb weight bearing, by inserting the needle perpendicular to the skin to the hub beneath the heavy layer of palmar metacarpal fascia (distal extent of the carpal flexor retinaculum) and dorsal to the DDFT, slightly distal to the level of the carpometacarpal (CMC) joint. Nerves are not palpable at this level because of the presence of the palmar metacarpal fascia (carpal retinaculum flexorum), but the position of the dorsal surface of the DDFT can be estimated from extrapolating the vertical groove between the suspensory ligament and the DDFT proximally. 2 to 3 mL of local anesthetic solution is injected at each site.
Medial and lateral palmar metacarpal nerves is at the same level relative to the CMC joint, but the limb is held with the carpus flexed.
The needle (21- to 23-gauge, 3.8-cm needle) is inserted axial to the head of MCII and MCIV perpendicular to the palmar cortex of MCIII, until it contacts bone.
A total of 2 mL of local anesthetic solution is injected on both sides of the limb.
variation of the subcarpal, high 4-point block
performing the medial palmar nerve block by using a** longer needle (38–50 mm)** and advancing it from the** lateral injection site towards the medial palmar nerv**e, dorsal to the DDFT.
A variation on the medial palmar metacarpal nerve block is to redirect the needle in a dorsomedial direction from a subcutaneous position, after having performed the lateral palmar metacarpal nerve block, towards the interface between MCII and MCIII until the needle contacts bone.
Lateral Palmar Nerve Block
2 tecniques, WB or flexed:
**
1) Lateral approach to the lateral palmar nerve (Wheat block)**
the lateral palmar nerve is blocked as it runs along the distopalmar border of the accessoriometacarpal ligament. A 25-gauge, 16-mm needle is inserted to its hub in a palmarolateral to dorsomedial direction at the distal aspect of the accessory carpal bone. A total of 5 mL local anesthetic
2) Medial approach can be blocked as it courses medial to the accessory carpal bone. 25-gauge, 16-mm needle is inserted perpendicular to the longitudinal vertical groove on the medial aspect of the distal third of the accessory carpal bone and advanced in a mediolateral direction until the needle contacts the bone. The needle is slightly withdrawn and 1.5 to 2 mL of local anesthetic is injected
Median and Ulnar Nerve Blocks
site for blocking the ulnar nerve is about **10 cm proximal to the accessory carpal bone in the groove that separates the ulnaris lateralis** and flexor carpi ulnaris muscles - total of **10 mL **of local anesthetic is injected through a 25- to 20-gauge needle inserted to a depth 1 to 2.5 cm (the nerve lies just under the antebrachial fascia).
Distal Interphalangeal (DIP) Joint mention how many approach
1) dorsal parallel approach
2) dorsal inclined approach
3) lateral approach
Describe Dorsal parallel approach
the needle is inserted parallel to the bearing surface of the foot through or immediately proximal to the** coronary band** through the digital extensor tendon
Describe Dorsal inclined approach
needle is inserted perpendicular to the skin surface immediately proximal to the coronary band - avoidance of needle placement through the highly innervated coronary band and accommodation of diverse foot shapes and positions.
Describe Lateral approach
site for needle insertion for the lateral approach is a depression in the proximal border of the lateral collateral cartilage that is palpable near the palmar border of the middle phalanx. The needle is inserted through the skin,** 2 cm above the palpable depression in the proximal edge of the lateral collateral cartilage. The needle is directed in a lateromedial direction, angled 45 degrees distally medially** and 20 degrees dorsally to penetrate the palmar pouch of the DIP joint, which is entered at a depth of penetration less than 2.54 cm.
Can the navicular bursa and DDFT sheath be inadvertently entered by the needle?
YEs if a needle longer than** 2.54 c**m is used, or if the procedure is performed with the limb held in a flexed position.
Podotrochlear (Navicular) Bursa has how many techniques?
distal palmar approach to the “navicular position”
lateral approach
distal palmar approach describe to navicular
Hickman foot block
20-gauge, 8.9-cm spinal needle is inserted** between the bulbs of the heel just proximal to the coronary band**, and the needle is advanced along a sagittal plane aiming for a point 1 cm below the coronary band, midway between the dorsal and palmar limits of the coronary band.
The spinal needle is advanced until the needle contacts bone (4–5 cm for most horses)
Take radiograph LM to check the position prior injecting 3 mL of anesthesia
lateral approach describe to navicular
foot in a Hickman foot block
microconvex ultrasound transducer placed longitudinally in the distal pastern region - tipped 45 degrees laterally, thereby coming to lie obliquely, axial to the lateral ungular cartilage, with the center beam pointing dorsally.
a 20-gauge, 75-mm spinal needle is inserted just proximal to the lateral collateral cartilage of the distal phalanx, between the palmarolateral border of the middle phalanx and the lateral border of the DDFT, and proximal to the navicular position.
The needle is advanced in a proximolateral to distomedial oblique trajectory in the frontal plane of the limb at an angle of approximately 45 degrees to the solar plane of the foot
Do not penetrate DDFT or lateral collateral sesamoidean ligament
Proximal Interphalangeal (PIP) Joint how many approach?
dorsal approach
dorsolateral approach
palmaroproximal approach
palmarolateral approach
dorsal approach to PIP
horse bearing weight on the limb
The needle is inserted on the dorsal midline anywhere from 1 cm distal to 1 cm proximal to an imaginary horizontal line drawn between the medial and lateral eminences on the distal end of the proximal phalanx and is directed slightly distally and medially
dorsolateral approach to PIP
needle is inserted anywhere between 1 cm distal to 1 cm proximal to the level of the lateral eminence on the distal end of the proximal phalanx at the edge of the common digital flexor tendon.
The needle is directed medially, parallel to the bearing surface to enter the dorsal pouch.
palmaroproximal approach to PIP
limb is held in flexion and the needle is inserted into a V-shaped depression formed by the palmar aspect of the proximal phalanx dorsally, and the lateral branch of the superficial flexor tendon as it inserts on the middle phalanx palmarly. The needle is directed distomedially at an angle of 30 to 45 degrees from the transverse plane
palmarolateral approach to PIP
the limb is held with the DIP and PIP joints in flexion. The needle is inserted immediately proximal to the lateral bony prominence on the proximopalmar border of the middle phalanx. The needle is inserted** perpendicular to the sagittal plane** close to the palmar border of the proximal phalanx and is directed medially, perpendicular to the long axis of the middle phalanx.
Digital Flexor Tendon Sheath (DFTS) how many approach?
can be entered at any of the lateral pouches evident along its length palmar/plantar axial
- sesamoid approach,
- basilar sesamoidean approach
- distal approach on the palmar/plantar aspect of the pastern between the proximal and distal digital annular ligaments where the deep digital flexor tendon lies subcutaneously.
How to access the distal pouch DFTS
access the pouch at this location, the tip of the needle must remain superficial to the deep digital flexor tendon
palmar/plantar axial sesamoidean approach DFTS
needle is placed at the level of the midbody of the lateral proximal sesamoid bone, 3 mm axial to its palpable palmar/plantar border and palmar/plantar to the palmar/plantar neurovascular bundle. The needle is advanced through the skin and palmar/plantar annular ligament of the MCP/MTP joint at an angle of 45 degrees to the sagittal plane, aiming toward the central intersesamoidean region, to a depth of 1.5 to 2.0 cm.
basilar sesamoidean approach DFTS
he MCP/MTP region is held in slight flexion, needle is inserted distal to the lateral proximal sesamoid bone into a palpable depression created by the base of this bone and the lateral border of the superficial flexor tendon. The needle is advanced in a lateromedial direction, approximately 45 degrees to the transverse plane, and in a distoproximal direction, approximately 45 degrees to the dorsal plane, to a depth of 1 cm or less.
Metacarpo-/Metatarsophalangeal (Fetlock) Joint how many approach?
collateral sesamoidean ligament approach
dorsal approach to the MCP/MTP
MCP joint basilar sesamoid
collateral sesamoidean ligament approach
the limb is held with the joint slightly flexed.
Landmarks for needle insertion are the lateral palmar/plantar aspect of the lateral condyle of MCIII/MTIII and the lateral articular margin of the lateral proximal sesamoid bone.
needle is inserted into this V-shaped gap and advanced in a direction perpendicular to the long axis of the limb
Figure 73-2. Needle positions for a palmar digital nerve block (a), abaxial sesamoid nerve block (b), palmar/plantar nerve block (c) and palmar/plantar metacarpal/metatarsal nerve block (d), and lateral palmar nerve block (e) are shown. The ramus communicans (f) connects the palmar nerves
Figure 73-3. Needle positions for a median nerve block (a), an ulnar nerve block (b), and a nerve block of the medial cutaneous antebrachii (c) are shown.
Figure 73-5. The limb is held with the foot in flexion in a Hickman foot block, for navicular bursocentesis with the needle directed to the navicular position (Verschooten approach).
Figure 73-6. A needle is placed in the proximal interphalangeal joint using a lateral palmar approach (a). A spinal needle is placed in the navicular bursa using the distal, palmar approach to the “navicular position” (Verschooten approach) (b) or an ultrasound-guided lateral approach (c)
approach to the proximal part of the palmar/plantar pouch
ocated between the palmarodistal/plantarodistal aspect of MCIII/MTIII, the dorsal edge of the lateral branch of the suspensory ligament, the distal end of the MCIV/MTIV, and the lateral, proximal sesamoid bone. If the pouch is distended, the site of entry is obvious as a so-called articular “windgall.” The needle is directed at a slightly downward angle into the middle of the lateral aspect of the palmar/plantar pouch.
dorsal approach to the MCP/MTP region
Needle is inserted under the lateral edge of the common digital extensor tendon at the palpable joint space and directed medially and slightly palmarly/plantarly.
Antebrachiocarpal and Middle Carpal Joints do not communicate. Enunciate the site os puncture
carpal joints can be approached dorsally with the carpus held in a flexion angle of 30 to 45 degrees or laterally with the horse bearing weight on the limb. For the dorsal approach to the antebrachiocarpal (ABC) joint, a needle is inserted in the depression found medial to the tendon of the extensor carpi radialis muscle between the distal edge of the radius and the proximal edge of the radial carpal bone
dorsal approach to the middle carpal joint the needle is inserted in the depression found medial to the tendon of the extensor carpi radialis muscle between the distal edge of the radial carpal bone and the proximal edge of the third carpal bone.
lateral approach to the ABC joint
lateral approach to middle carpal joint
performed with the limb bearing weight. The needle is inserted in a depression that can be palpated 1.3 to 2.5 cm below the convergence of the tendons of the ulnaris lateralis and lateral digital extensor muscles on the palmarolateral aspect of the carpus. The needle is inserted perpendicular to the skin surface
horse bearing weight on the limb the middle carpal joint can also be entered on the palmarolateral aspect of the carpus, in a slight depression located about 2.5 cm distal to the site of injection of the antebrachiocarpal joint perpendicular to the skin
Carpal Sheath of the Superficial andDeep Digital Flexor Tendons what is the approach?
Lateral approach with limb flexed between the
ulnaris lateralis and lateral digital extensor tendon about 1.2 cm proximal to the distal radial physis
20-gauge, 3.8-cm needle is directed distomedially to its hub at a 60-degree angle to the long axis of the limb. A total of **10 to 20 mL **of local anesthetic solution is injected.
Describe insertion of needle in cubital lateral approach
site of centesis lies at the junction of the proximal two-thirds and distal one-third of the distance **between the lateral epicondyle of the humerus **and the lateral tuberosity of the radius in a palpable depression immediately caudal to the lateral collateral ligaments.
A 3.8-cm needle is advanced perpendicularly to the long axis of the limb to its hub
The Cubital (Elbow) Joint how many approach?
lateral approach
caudolateral approach
Describe insertion of needle in cubital caudolateral approach
site of needle insertion for this approach lies in a depression found near the distal border of the triceps muscle and immediately caudal to the lateral epicondyle of the humerus. In this depression, a 3.8-cm needle is advanced in a craniomedial direction in a horizontal plane
Inadevet local anesthestetic during attempeted centesis of cubital joint may result in anesthesia of each nerve? what is the result? what shoud you do?
deep branch of the radial nerve, which causes paralysis of the extensor carpi radialis and common digital extensor muscles, necessitating splinting of the carpus and preventing further examination.
Scapulohumeral (Shoulder) Joint has how many approach?
craniolateral approach
lateral approach
describe craniolateral approach of the scapulohumeral joint
an 8.9-cm spinal needle is inserted in the notch** between** the cranial and caudal portions of the greater tubercle of the humerus. The needle is advanced in a medial direction, aiming slightly caudally (20–30 degrees) and slightly distally (10–15 degrees)
describe the lateral approach to the scapulo-humeral joint
the spinal needle is inserted immediately caudal to the proximal margin of the caudal portion of the greater tubercle. The needle is directed perpendicular to the skin surface until it is felt to strike cartilage
Do not inject local anesthesia in scapulohumeral joint unless there is synovial fluid why?
Periarticular deposition of local anesthetic may result in paralysis of the supraspinatus and infraspinatus muscles by means of blocking the suprascapular nerve
Does a communication exist between the scapulohumeral joint and the biccipital bursa?
YES in some horses
Bicipital Bursa describe the approach
9-cm 18- to 20-gauge spinal needle is inserted 3.8 cm proximal to the distal aspect of the **deltoid tuberosity and advanced dorsocranially for 5 to 7.5 cm (aiming for the bicipital groov**e and the opposite ear of the horse). The needle is advanced until there is a distinct change in resistance –> few chance to get unless US guided
cranial transtendinous approach = highly accurate For this approach, the limb is raised and an 18- or 20-gauge, 8.9-cm spinal needle is inserted in a craniocaudal direction, several centimeters medial to the cranial portion of the greater tubercle (i.e., point of the shoulder) with the scapulohumeral joint extended and the cubital joint flexed 15-20 mL are injecte after “pop” through the tendon
Is the ramus communicans existent in the HL?
(ramus communicans) that connects the lateral and medial plantar nerves is usually either rudimentary or nonexistent in the pelvic limb,
High 4-Point Nerve Block
Anesthesia of the dorsal metatarsal nerves is performed 2 cm distal to the level of the TMT joint, by injecting** 2 mL **of local anesthetic at the 10 and 2 o’clock positions of the distal or proximal dorsal metatarsal region
Palmar is the same as for the FL with the difference that the inadvertent injection of the TMT is less likely than CMC
Deep Branch of the Lateral Plantar Nerve(DBLPN) Block
15 mm distal to the articular surface of MTIV, the superficial digital flexor tendon (SDFT) is deflected** medially away** from the** axial border of MTIV** and a 25-mm needle is inserted perpendicular to the skin surface of the proximal plantar metatarsal region. The needle is advanced to its hub in the sagittal plane of the limb, between MTIV and the lateral border of the SDFT
Tibial nerves gives off
**medial **and **lateral plantar nerves, **and because the deep branch of the lateral plantar nerve supplies sensory innervation to the suspensory ligament, blocking the tibial nerve will improve or abolish lameness caused by proximal suspensory desmitis
The peroneal nerve supplies…
joints of the tarsus. For this reason you can do separetly to clarify which is causing the lameness if LSB or TMT
Tibial nerve block
10 cm proximal to the point of the tarsus. The nerve can be approached from** lateral** or from medial with the limb bearing weight or lifted.
The neurovascular bundle can be palpated on the flexed limb between the calcaneal tendon and the DDFT at the site of injection. The needle is inserted over the caudal surface of the deep digital flexor muscle to lie close to the palpable neurovascular bundle
15-20 mL
Common peroneal nerve can also be anesthtized more proximal, where?
common peroneal nerve can also be anesthetized where it emerges from beneath the biceps femoris muscle, before it divides into its superficial and deep branches. The site for anesthesia of the common peroneal nerve is found by palpating the tibial tuberosity and the lateral condyle of the tibia. The needle is inserted through skin and fascia, at a distance caudal to the lateral condyle of the tibia that is equal to the distance between the tibial tuberosity and the lateral condyle of the tibia, and at the distal extent of the first division of the biceps femoris muscle. The nerve lies just under fascia. A total of 10 to 15 mL of local anesthetic solution is injected
After blocking the peroneal what can happen to the horsE?
buckle at MTP joint as sign of extensor muscle paralysis and you may have to stop the lameness exam
Landmarks to block TC joint
dorsomedial pouch on either side of the saphenous vein or at the lateroplantar pouch that may protrude between the calcaneus and the lateral malleolus of the tibia if joint effusion is present
10-20 mL of LA
Landmarks to block TMT
plantarolateral approach to the TMT joint
palpable landmark for needle placement is the head of MTIV.
20- or 21-gauge needle is inserted 0.6 cm above the head of the lateral splint bone and 1.3 cm lateral to the lateral edge of the SDFT.
The needle is directed slightly downward, towardthe dorsomedial aspect of the tarsus
Landmarks to block DIT dorsomedial approach
Dorsomedial approach
distomedial aspect of the tarsus
midway between the plantar and dorsal aspects ofthe distal portion of the tarsus
with the limb bearing weight
The site of needle insertion lies near the point where the distal border of the fibularis tertius (cunean) tendon crosses the horizontal depression between the proximal and distal rows of tarsal bones.
A 1.6- to 2.5-cm, 23- to 25-gauge needle is inserted into the proximal part of the small, T-shaped gap formed by the junction of the fused first and second tarsal bones, the third tarsal bone, and the central tarsal bone.
dorsolateral approach to the DIT joint.119
DIT dorsolateral approach
Dorsolateral approach
2 to 3 mm lateral to the LDET and 6 to 8 mm proximal to a line drawn perpendicular to the axis of MTIII through the proximal end of MTIV. The needle is directed plantaromedially at an angle of approximately 70 degrees lateral to the sagittal plane.
Because of the high incidence of inaccuracy accessing this joint using either technique, contrast arthrography may be useful to confirm accurate arthrocentesis.
Landmarks to block cunean bursa
inserting a needle directly through the cunean tendon into the bursa at the level of the DIT joint.
or
needle can also be inserted at the distal edge of the cunean tendon and directed proximally beneath the tendon, which travels from a dorsoproximal to plantarodistal direction on the medial aspect of the tarsus
Tarsal sheath or sheath of the lateral digital flexor tendon
digital flexor tendon
2 mm plantar to the plantaromedial palpable edge of the sustentaculum tali of the calcaneus
20 G needle in craniolateral direction 10-15 mL of LA
Calcaneal bursae
gastrocnemius calcaneal bursa, the needle is inserted perpendicular to the long axis of the limb on the lateral aspect of the limb, 1 cm proximal to the most proximal palpable aspect of the tuber calcanei
approximately 1 cm dorsal to the insertion of the gastrocnemius tendon on the tuber calcanei
intertendinous calcaneal bursa, the needle is inserted 1 cm distal to the superficial flexor tendon retinaculum dorsal to the superficial flexor tendon and plantar to the calcaneus, on the lateral or medial aspect of the limb
Describe the common block for FP joint
FP joint can be accessed by inserting a 3.8-cm needle between the middle and medial patellar ligaments or between the middle and lateral patellar ligaments, 2.5 to 4 cm proximal to the tibial tuberosity.
The needle is inserted parallel to the ground through the large fat pad between the patellar ligaments and joint capsule. 20 mL
Other tx lateral cul-de-sac of the joint
needle is inserted approximately** 5 cm proximal to the lateral tibial condyle, just caudal to the lateral patellar ligament and directed lateromedially,** perpendicular to the long axis of the limb
What is the percetage of communication between FP and MFT joints?
65%
Medial compartement of FT joint
medial patellar ligament and the **medial collateral femorotibial ligament just proximal to the palpable** proximomedial edge of the medial meniscus
needle is directed slightly proximally to penetrate the widest portion of the medial cul-de-sac of the joint, at a depth of 1.9 to 2.5 cm
Other tx indentation between the medial patellar ligament and the tendon of the sartorius muscle about 2.5 cm proximal to the tibial plateau.
The needle is advanced in a cranial-to-caudal direction parallel to the ground.
The medial cul-de-sac of the joint is penetrated at a depth of about 2.5 cm
Lateral compartment of FT joint
by inserting a needle into a diverticulum of the compartment (the subextensorius recess or bursa of the long digital extensor tendon).
Inserting the needle 1 to 4 cm distal to the proximolateral edge of the tibia, directly through the** center of the tendon of LDE m.** until the tip of the needle contacts bone
The needle is retracted slightly before LA solution is injected.
Injection is easier if the horse is not bearing full weight on the limb.
The diverticulum contains which structures?
The** diverticulum** contains the combined
tendon of the long digital extensor muscle
the peroneus tertius
and extends distally about 7.5 cm from the tibial plateau.
Centesis of all three compartments in single site
After desensitizing the skin at the injection site, an** 8.9-cm spinal needle** is inserted between the lateral and middle patellar ligaments, 1 to 2 cm proximal to the proximal articular surface of the tibia.
80-degree angle relative to the long axis of the tibia and **medially at a 30-degree angle **toward the medial axial aspect of the medial femoral condyle, which will place its tip within the medial compartment of the femorotibial joint.
withdrawn to a subcutaneous position and directed **proximally at an 80-degree angle relative to the long axis of the tibia **a few degrees laterally toward the cranial aspect of the **lateral femoral condyle to place its tip within the lateral compartment of the femorotibial joint.**
again withdrawn to a subcutaneous position and then directed proximally at approximately a 20-degree angle relative to the long axis of the tibia with no medial or lateral angulation to the intertrochlear groove to place its tip within the femoropatellar joint.
What was the accuracy for accessing all 3 compartments? and for individual compartment?
80% and 90% respectively
Throchanteric bursa injection of the coxofemoral joint
Place the foot in Hickman block
20- or 18-gauge spinal needle is inserted over this portion of the greater trochanter and advanced until it contacts bone. It can be seen US during injection
10-15 mL of LA
Coxofemoral joint approach
Landmarks for needle placement are the** cranial and cauda**l portions of the greater trochanter, which is found three-fourths of the distance from the tuber coxae on a line connecting the tuber coxae and the tuber ischii. The caudal portion of the greater trochanter is more easily palpated than the cranial portion. Once the caudal portion of the greater trochanter is palpated, the cranial portion can be found several centimeters cranial and distal to the caudal portion. Both portions of the greater trochanter are more easily palpated if the horse is not bearing full weight on the limb. A 15.2- to 25.4-cm, 18-gauge spinal needle is inserted 1.3 cm proximal to the middle of the ledge of the cranial portion of the greater trochanter rather than at the notch between cranial and caudal portion of the greater trochanter, as often described. **Needle advance medially **and directed 10 degrees distally and 35 degrees cranially until feel a pop. 20-25 ml LA
Coxofemoral joint approach is close to which nerve and what can be the consequences?
Sciatic nerve and temporary limb paresis
If you do not have synovial fluid in the coxofemoral joint should you inject the LA?
No, it is not advised
Can cause limb paresis if sciatic nerve is indavertently anesthetized
SI joint has how many approach
Blind craniomedial approach
US aided injection cranial + caudal approac
Describe blind craniomedial technique
Site of needle insertion is 2 cm cranial to the contralateral tuber sacrale.
A stab incision is recommended to facilitate advancement of the needle.
A 25-cm, 18- to 15-gauge needle is bent 40 degrees in the direction of the needle’s bevel.
The needle is inserted at a 40-degree angle to the horizontal plane with the bevel facing upward and advanced in an oblique caudolateral direction towards a spot half way between the cranial aspect of the tuber coxae and the cranial portion of the greater trochanter.
The needle is advanced across the midline until the needle shaft encounters the medial aspect of the contralateral** iliac wing.**
The needle hub is then elevated, so that the needle can be advanced at a steeper angle (50 degrees) further along the medial surface of the ilium until it stops against the transverse processes of the sacrum, adjacent to the sacroiliac joint at a depth of 15 to 20 cm from the skin surface
US aided injection of SI
**Cranial approach 5 mHz convex ultrasound parallel to spinal column 5 to 7 cm off the midline
15- to 20-cm needle is inserted from a point on a transverse line joining the cranial aspect of both tuber coxae and cranial to the ultrasound probe.
The needle is inserted at an angle that will cause it to pass beneath the wing of the ileum to contact the** transverse processes of the sacrum**
caudal approach
the probe is placed caudal to the tuber sacrale, in a craniolateral to caudomedial oblique plane, leaving 3.8 to 5 cm of space between the probe and the dorsal spinous processes of the sacrum to allow needle placement
**15-cm needle **is inserted between the probe and the dorsal spinous processes of the sacrum and advanced in a caudodorsal to cranioventral direction. As soon as the needle is imaged, it is directed toward the caudal margin of the ipsilateral SI joint
Caudal approach is prudent to not inject LA, why?
sciatic nerve and limb paralysis
Thoracolumbar interspinous process how much time to access the block and how is evaluated?
20 minutes and is evaluated when observing the horse while is ridden
Cervical articular process joint
Us guidance 5-10 MHz
Dorsal approach
Us is perpendicular to the long axis of the **cervical vertebra **and **cervical articular facets is visualized 6 to 8 cm proximal **to transverse process
8.9 cm 18-20G spinal needle is inserted at the dorsal edge of the probe and directed in an angle of 20º toward the joint
Dorsocranial approach
the US is placed 45º to the long axis of the cervical vertebra and advanced cranially
Cranial approach the US is oriented parallel to the long axis of the neck and the needle is inserted cranial or caudal to the transducer
Thoracolumbar intervertebral articular process
T15-L1 most OA
3.5-5MHz curvilinear array transducer is placed next to spinous process in** transverse plane**
Intervertebral facet joint is ID
8.9 cm 18-20 G spinal needle US
If needle is axial to US is direct almost vertically and advanced downward
Needle placed abaxial to the US probe to the US it is directed 40 degrees to the vertical plane
