Week Five: LA Local Complications

Question 1

What are local complications?

Answer 1

• Failure to achieve LA
• Pain during injection
• Sensitivity disorders
• Needle breakage
• Needle track infection
• Trismus
• Haematoma
• Facial Nerve Paralysis
• Soft tissue lesion
• Mucous membrane lesion
• Other intraoral lesion

Question 2

What causes failure?

Answer 2

• Inadequate dose:
• Not enough to effectively cause conduction blockade across several nodes of ranvier.
• Acute inflammation - may require a course of ABs: low tissue pH affects onset of action of LA
• Injection into blood vessel
• Inadequate patience
• Incorrect technique/unusual anatomy
• Expired L.A or not stored adequately.

Question 3

What is the volume of the pterygomandibular space?

Answer 3

Approx 3.6mls

Question 4

If you increase the volume of solution i.e. lignocaine what is the result?

Answer 4

Increasing the volume has shown to improve success rates in patients who have symptoms of pulpitis

However increasing volume in asymptomatic teeth does not result in FASTER onset of pulpal anaesthesia of mandibular teeth.

Question 5

What causes pain on injection?

Answer 5

◦ Careless technique
◦ Too rapid injection- torn tissues
◦ Subperiosteal injection
◦ Solution is too warm or too cold
◦ Pronounced- needle unintentionally pricks an anatomical structure
({electric shock- nerve}, tendon, periosteum, muscle)

Question 6

How can you prevent pain on injection?

Answer 6

◦ Know your landmarks, have a good technique, inject solution SLOWLY
◦ Bevel facing bone
◦ Make Sure L.A is room temp when injecting

Question 7

How do you manage pain on injection?

Answer 7

No management necessary, however take steps to avoid reoccurrence of
pain

Question 8

How do sensitivity disorders manifest?

Answer 8

Prolonged anaesthesia or paraesthesia
May manifest as:
• Burning or tingling
• Persistent/permanent anaesthesia
• Tingling or pins and needles: paraesthesia
• Increased sensitivity to noxious stimuli: hyperesthesia
• Pain to non- noxious stimuli: dysesthesia

Question 9

What causes sensitivity disorders?

Answer 9

Causes
• Very rarely is sensitivity disorder a result of local anaesthesia type
• i.e. misconception s around Articaine IAN Blocks
• Trauma to nerve impairs nerve conduction
• Direct trauma by needle or indirect
• Administration of L.A from a cartridge contaminated by alcohol or sterilisation > irritation > oedema
• Haemorrhage into or around nerve sheath > intraneural hematoma > increase pressure
• Risk of nerve damage is greater if repeated injections are given into a previously partially anaesthetised site

Question 10

What is the deal with paraesthesia and Articaine?

Answer 10

• Historically, concerns regarding its safety
• Neurotoxic > Nerve damage
• Many studies that reported this had questionable validity

Question 11

How do you prevent and manage prolonged anaesthesia or paraesthesia?

Answer 11

• Prevention
◦ Adherence to injection protocol

• Management
◦ Duration determined by extent of damage to the nerve
◦ Pt is likely to call after several hours when L.A still has not worn off.
◦ Speak to pt personally, reassure and advise that it is not uncommon after L.A administration
◦ Mostly transient and will resolve within 8 weeks
◦ Examine pt and determine degree and extent of paraesthesia - DOCUMENT!! have pt reviewed by DO if necessary
◦ If transition from anaesthesia to paraesthesia good chance of recovery
◦ If unresolved after 8 weeks likely it is irreversible, pt will require a consult with a neurologist or oral surgeon, because if left longer without action, may be permanent

Question 12

What are the causes of needle breakage?

Answer 12

Causes:
◦ Rare
◦ Strong indication in cases reported that needle had been bent first & that needle was inserted in its entire length
◦ It is believed that smaller diameter needles 30gauge) are more likely to break (usually occurs at hub)
◦ Sudden movement of pt may increase risk

Question 13

What are preventative measures to avoid breakage?

Answer 13

◦ Larger gauge needle
◦ Long needle if inserting >18mm into soft tissue
◦ Don’t insert all way into hub
◦ Don’t apply extensive lateral pressure whilst needle is inserted into soft tissue

Question 14

How do you manage needle breakage?

Answer 14

• Remain calm, ask pt to remain still
• If portion of needle visible: remove it!
• If not visible: inform pt, document event and refer pt to a maxillofacial surgeon
• DOCUMENT!!!!!

Question 15

What is a needle track infection?

Answer 15

If inject into area of inflammation or abscess
you run the risk of introducing infection into
the surrounding healthy tissues

• Directly: needle is contaminated when it
perforates infected area, this needle is used to
deposit solution into deeper healthy tissues

• Indirectly: If L.A deposited under pressure
(periodontal ligament injection) the force of
administration might transport bacteria into
healthy adjacent tissues

Question 16

What is trismus?

Answer 16

Relatively common complication. Defined as a prolonged spasm of the jaw muscles which impairs the normal opening of the mouth (often associated with pain)

• Symptoms will arise 1-6 days post injection

Causes:
◦ Needle insertion into muscles (usually medial pterygoid during an IAN block)
◦ Haemorrhage
◦ Bleeding into the muscles following injection
◦ Injection directly into muscle > mild myotoxic response that leads to necrosis of exposed muscle fibres.

Question 17

How do you prevent trismus?

Answer 17

◦ Adherence to injection protocol
◦ Avoid repeat injections, and multiple insertions
◦ Use minimum effective volumes of L.A

Question 18

How do you manage trismus?

Answer 18

◦ With mild pain and dysfunction
- Interim tx: Heat, saline rinse, analgesic
- CONSULT WITH DENTAL OFFICER (DO to prescribe muscle relaxant/stronger analgesia/Ab if necessary)
- Will usually disappear in 7-10 days
- Patient to perform daily mouth exercises
- DOCUMENT!!!!
◦ If severe pain, if ability to open mouth at all is limited, or if trismus lasts longer than outlined above, refer pt to maxillofacial surgeon

Question 19

What causes facial nerve paralysis?

Answer 19

◦ Introduction of L.A into capsule of parotid gland, results in unilateral paralysis of muscles of facial expression (bells palsy)

Question 20

How can you prevent facial nerve paralysis?

Answer 20

◦ Adherence to injection protocol, ensure that slight resistance (needle nudging bone) is felt prior to deposition of L.A for an IAN

Question 21

How do you manage facial paralysis?

Answer 21

◦ Reassure pt and advise that paralysis is normally transient and will last for duration of soft tissue anaesthesia
◦ Ask them to remove any contact lenses
◦ Get pt to wear an eye patch
◦ DOCUMENT!!!!

Question 22

What causes soft tissue injury?

Answer 22

◦ Frequently lip, tongue or cheek bite in younger children, mentally or physically disabled clients- can lead to swelling and causes significant pain when the L.A effects resolve

Question 23

How can you prevent soft tissue injury?

Answer 23

◦ Select L.A of appropriate duration for the client
◦ Cotton role in mouth
◦ Post Operative Instructions to Pt and Parent- DOCUMENT!!!!
◦ Warning stickers

Question 24

How can you manage soft tissue injury?

Answer 24

◦ Analgesics, saline mouth rinse, Vaseline

◦ If severe tissue laceration, or signs of systemic involvement discuss with DO, who may need to prescribe antibiotics

Question 25

What causes haematoma?

Answer 25

◦ Effusion of blood into an extravascular space, most likely from inadvertently nicking a blood vessel
◦ Common in
- pterygoid plexus of veins, posterior superior alveolar vessels, inferior alveolar vessels, & the mental vessels
- If occurs in Pterygomandibular space, may lead to swelling in pharyngeal arch and slight trismus

Question 26

How do you prevent haematoma?

Answer 26

Good knowledge of anatomy and aspiration

Question 27

How do you manage haematoma?

Answer 27

◦ Immediate
- Apply direct pressure until bleeding stops
◦ Subsequent
- Advise pt about possible soreness
- Apply ice intermittently for first 4-6 hours (no heat)
- Expect discoloration and wait for the reduction in swelling &/or bruise. Usually lasts 7-14 days
- Advise client to notify you if malaise of trismus following Haematoma

Question 28

What causes mucous membrane lesions?

Answer 28

Prolonged ischemia of tissues as a direct result of
vasoconstrictor, or reaction on mucous tissues to
anaesthetic agent

Question 29

How can you prevent mucous membrane lesions?

Answer 29

• Only use topical for 1-2 mins

* Try not to use overly concentrated vasoconstrictors in L.A

Question 30

How do you manage mucous membrane lesions?

Answer 30

• Reassure patient

* Analgesics if required, saline mouth rinse, ointment

Question 31

What are some other intraoral lesions? What are the causes?

Answer 31

• Patients occasionally report a couple of days after L.A that ulcerations have developed in their mouth primarily around injection site
• Thought that trauma to tissues may activate latent form of disease
• Causes:
  ◦ Recurrent Apthous Stomatitis
  ◦ Herpes Simplex

Question 32

How do you manage intraoral lesions?

Answer 32

Management:
◦ Primarily manage pain, assure pt that not bacterial infection but the exacerbation of a process that was already present in latent form
◦ Refer to DO for scripts for topical agents to help relieve discomfort if required