Complications to local anesthesia

What is the most common complication of local anesthesia?

post-injection pain

_____ can become one of the more common chronic and complicated problems to manage

Trismus

What are some localized complications to the administration of LA?

• needle breakage

• prolonged anesthesia or paresthesia

• facial nerve paralysis

• trismus

• soft tissue injury

• hematoma

• poin on injection

• burning on injection

• infection

• postanesthetic intraoral lesions

Needle breakage rate?

Pogrel published that N California dentist rate of broken needles at 1/14 million IANBs

Highest risks of needle breakage

• IA nerve block

• 30-gauge short needle

• needles broken at the hub

Factors contributing to needle breakage

• intentional bending of the needle before injection

• sudden unexpected movement by the pt while the needle still within the soft tissue

• forceful contact w bone

Needle breakage management

• stay calm

• attempt to retrieve

• immediate referral to specialist (OMFS) for evaluation and possible attempted retreival

• imaging

Needle breakage prevention

• no short needles for IANB

• no 30-gauge short needles for adults or children

• do not bend the needle

• do not hun needle

• do not flex needle forcefully against bone

• exercise caution in children and phobic pts (unexpected movement)

Causes for prolonged anesthesia or paresthesia

• trauma to the nerve or nerve sheath

• injection w neurotoxic/ neurolytic substance (alc/ sterilizing solution)

• hemorrhage into or around the neural sheath

• LA solution itself

Most paresthesia resolve within ___ weeks w/o treatment

8 weeks

Facial nerve paralysis cranial nerve? Cause?

• CN VII, facial nerve

• Cause: introduction of LA into the capsule of the parotid gland/ too far post during IANB/ over insertion during Akinosi injection

Trismus

prolonged tetanic spasm of the jaw muscles by which the normal opening of the mouth is restricted

Most common cause of trismus

trauma to muscles or blood vessels in the infratemporal fossa secondary to the dental injection of LA

• LA are slightly myotoxic

The ____ needle penetrations, the ____ the probability of tissue damage and/or hemorrhage

The more needle penetrations, the greater the probability of tissue damage and/or hemorrhage

Trismus prevention

• Not always preventable

• use sharp needle

• properly care for the cartridges

• use aseptic technique if possible

• practice atraumatic technique

• avoid repeat injections and multiple insertions

• use only the effective volumes of LA

Trismus management

• treat w/ heat therapy: warm saline rinses

• analgesics, muscle relaxants, anti-inflammatory medications

• pt physical therapy

Hematoma

• effusion of blood into the extravascular spaces

• likely due to nicking a vessel on the way in/out

• may cause trismus an dpain

hematoma management

• immediate hematoma: apply pressure to the site of bleeding for more than 2 mins

• no heat to the area for at least 4-6hrs. after hot compresses

Burning on injection cause

• pH of the solution

• rapid injection

• cross contamination of LA w/ alcohol or sterilizing solution

burning on injection prevention

• slow injection: idea rate is 1mL/min (palatal: 0.5mL/min)

post-anesthetic intraoral lesions causes

• recurrent aphthous stomatitis or herpes simplex

• trauma to the tissue