Nerve Blocks

Steven Lanski, MD

Assistant Professor Pediatrics and Emergency Medicine

Emory University

What is Pain?

What is Pain?

International Assoc for the Study of Pain: “an unpleasant sensory and emotional experience connected with actual or potential tissue damage…”

afferent impulses from averse stimuli

processing of that information

Factors Involved

Thickness

Myelination

Perception

Components of the Pain System: Sensation

Afferent fibers “A” delta fibers: mechanoceptors (pressure)

small, lightly myelinated …”first” pain rapid, sharp, localized

“C” fibers: polymodal (heat,chemical)unmyelinated (slower)…”second” paindelayed, prolonged, dull, poorly localized

Mechanism of Action

Decreases sodium influx across neuronal membranes

Decreases polarization amplitude

No action potential

No impulse

Duration of actionDependant upon protein binding and blood supply.

Adverse Reactions

Cardiovascular - hypotension, bradycardia

CNS - excitatory - seizures

Allergic - preservative - methylparabenesters - tetracaine, benzocaine, procaine, cocaineamides - lidocaine, bupivacaine, diphenhydramine (1%)

Anxiety

Locations

Facial Supraorbital and

trochlear infraorbital mental ear dental

Extremity digital radial median ulnar sural tibial

Supraorbital/Supratrochlear Blocks

Helpful for multiple lacerations of forehead and anterior scalp

Supraorbital/Supratrochlear Blocks

Landmark - superior orbital rim

Infraorbital BlockAnesthesia to lower eyelid, lateral inferior

nose and lower lip

Infraorbital Block

Landmarks - canine, infraorbital foramen

Mental Nerve BlockAnesthesia to lower lip and partial

chin

Mental Nerve BlockLandmark - 2nd bicuspid

Auricular Block

Dental Blocks

Local

Inferior Alveolar - anesthesia to the mandible, teeth and chin

Inferior Alveolar Block

Landmarks - ramus of the mandible and coronoid notch

Digital Blocks

Dorsal and palmar digital nerves

Toes (except 1st) single needle insertion

Digital Blocks

Landmarks - bone and web space

Thumb Block

Median Nerve Block

Anesthesia to palm (radial half), 1st-3rd digits Landmark - proximal flexor crease, radial artery,

flexor carpi radialis and palmaris longus tendons.

Ulnar Nerve BlockAnesthesia to dorsal and palmar aspect of hand (ulnar half), ulnar half of 4th digit and 5th digit Landmarks - flexor carpi ulnaris and ulnar artery

- dorso-ulnar aspect wrist (2nd branch)

Radial Nerve BlockAnesthesia to dorsal surface of 1st-3rd digits and radial portion of hand Landmark – dorso-radial aspect of wrist

Sural Nerve Block

Anesthesia to heel and lateral half of foot Landmarks - lateral malleolus, Achilles tendon

Posterior Tibial Block

Anesthesia to the medial aspect of the foot Landmark - posterior tibial artery, Achilles tendon

and medial malleolus

Penile Block

Landmarks - base of penis and Buck’s fascia

Conclusion

Choice of agents based on duration required

Beneficial for multiple or extensive injuries in which conscious sedation will not be performed

More comfortable than local infiltration in some sites