Contraindications and Complications of Local Anesthesia

1. Contraindications and Complications of Local Anesthesia

3. Local Complications • 1) Needle breakage • Causes and precipitating factors • Using small gauge needles • Using short needles for techniques requiring significant depth of penetration • Bending needles • Defect in manufacture • Sudden unexpected movement

4. Problem It is not a significant problem other than fear of needle migration and legal consideration

5. Management • Keep calm • Do not move • Remove it with small hemostat if a visible part is present • If not • Inform the patient • Refer to oral surgeon for consultation • In general if retrieval is difficult allow to remain

6. 2) Persistent anesthesia or parasthesia Hyperreactors; parasthesia for hours or days; not a problem When anesthesia or parasthesia lasts for days, weeks, months; it is a problem

7. Persistent anesthesia or parasthesia (cont..) • Signs and Symptoms • A patient clinical response varied including: Numbness, Swelling, Tingling, Itching, alone or with pain (hyperesthesia or dysesthesia) • Causes • Direct trauma: produced by contact with the needle e.g. maxillary nerve block • Injection of local anesthetic solution contaminated by alcohol or sterilizing solution near the nerve; edema and neurolytic effect • Hemorrhage into or around the neural sheath • The local anesthetic solution itself specially high concentrations 4% prilocaine and 4% articaine (1:500,000) Problem • Self-inflected injury • Pain

8. Persistent anesthesia or parasthesia (cont..) • Management • Most parasthesias resolve within approximately 8 weeks without treatment • It depends on the degree of damage • Most commonly involved the tongue then the lower lip • Management steps • Waiting 2 months is recommended • Follow-up every two months • If it is still evident 1 year after the incident consultation with a neurologist or oral surgeon is recommended.

9. 3) Facial nerve paralysis • Branches • Causes; IANB & Akinosi

10. Problem • Cosmetic: Unable to voluntarily close one eye Prevention • Management • Reassurance • Contact lenses should be removed • An eye patch should be applied

11. 4) Trismus • Definition • Causes • Trauma to muscles or blood vessels in the infratemporal fossa (IANB, PSA) • The diffusion of alcohol or cold sterilizing solutions into local anesthetic solutions • Local anesthetics themselves • Hemorrhage • Infection • Problem • Limitation of movement • Pain in the acute phase • Scar formation in the chronic phase

12. Management of trismus • Conservative • Heat therapy • Warm saline rinse • Drugs: analgesics, anti-inflammatory (aspirin, codeine) and muscle relaxants (Diazepam) • Physiotherapy : for 5 minutes every 3 to 5 hours • Chewing gum, Ultrasound, appliances • Patients usually report improvement within 2-3 days • Therapy should be continued until the patient is free of symptoms • If trismus and pain continue beyond 2 days consider the possibility of infection. Antibiotics should be added to the treatment regimen for 7 days • Complete recovery takes about 7 weeks(4-20weeks) • If no improvement is noted , the patient should be referred to oral surgeon for evaluation • TMJ involvement is rare in the first 4-6 weeks after injection, so surgery may be indicated • If continued dental care in the area is urgent Akinosi is indicated

13. Wooden spatula in use to improve trismus

14. 5) Soft-tissue injury • Causes • Problem

15. Prevention of Soft-tissue injury • Selecting a local anesthetic of appropriate duration if dental appointments are brief. • Placing a cotton roll between the lips and the teeth • Self-adherent warning sticker Management: antibiotics &analgesics as necessary

16. 6) Hematoma • Causes • Problem Trismus, pain, Swelling, discoloration • Prevention • Order of techniques have a greater risk of visible hematoma; PSA, IANB, the mental /incisive nerve block • Paying attention to the patient’s characteristics • Using short needle for the PSA • Minimize the number of needle penetration into tissue

17. Management • Immediate: IANB, ASANB, I(M)NB, BNB, PSANB • Subsequent: • If trismus develops treat as described • Analgesics if soreness develops • Heat application 4-6 hours later • Ice application • With or without treatment it will be present for 1-2 weeks

18. 7) Intra-vascular injection: Accidental intra-venous injection may produce dramatic systemic effects: • Visual disturbances: • Loss of vision: Temporary blindness in one eye most likely due to accidental intravascular injection , that reaches the Ophthalmic artery resulting in temporary loss of function of Optic nerve; • Diplopia: Due to accidental intravascular injection causing loss of motor function to the muscles of orbit. • Aural disturbances: Hearing loss due to LA. reaching the Internal auditory artery following intra-arterial injection • Extensive paralysis: Extensive temporary paralysis on one side of the body can be explained by inadvertent intra-arterial injection of LA., reaching to External carotid artery, then to the Internal carotid artery thus reaching to the brain.

19. 8) Pain on injection • causes • Pain during injection • Pain at the time of injection is mainly due to poor technique and may be caused by the following: • Intraepithelial injection: This cause epithelial ballooning and is overcome by insertion of the needle into the sub-mucosa. • Sub-periosteal injection: The discomfort is due to injection into non-compliant tissue.

20. 3) Too rapid injection rate: A slow rate of injection reduces discomfort, ideal 30 seconds. • 4) Direct contact with nerve trunk: During block anesthesia ; this occur with experienced operators. • 5) Factors related to the solution: • PH: The presence of Adrenaline increase injection sensation due to the law PH (burning sensation). • Temperature: Cold solutions cause pain; should be allowed to reach room temperature before injection. • Contamination of the LA cartridges

21. II. Post-injection pain • Pain after the effects of the LA. have disappeared may be caused by: • Sub-periosteal injection: This is the result of stripping of the periosteum off the bone. • Forceful intraligamentary anesthesia: This may produce extrusion of a tooth leading to traumatic occlusion. • Problem: • Increases patients’ anxiety • Sudden unexpected movement • Tissue damage • Trismus, parasthesia, edema

22. 9) Sloughing of tissues • Causes: • Epithelial desquamation: resolves within few days • Sterile abscess may run from 7-10 days • Problem: pain, may infection • Management: • No formal management is necessary for either epithelial desquamation & sterile abscess

23. 10) Edema • Causes • Trauma • Infection • Hemorrhage • Injection of irritating solution • Allergy: angioedema • Hereditary angioedema • Problem • If sever: life threatening situation • Management • Non-allergy or LA- induced edema • Allergy-induced edema (angioneurotic edema)

24. 11) Postanesthetic intraoral lesions • Causes, Problem, Management • Reassurance • Viscous lidocaine • Orabase without Kenalog • The ulcerations usually last for 7-10 days with or without treatment