Contraindications and Complications of Local Anesthesia Local Complications

Contraindications and Complications of Local Anesthesia

Local Complications 1) Needle breakage Causes and precipitating factors ØUsing small gauge needles ØUsing short needles for techniques requiring significant depth of penetration ØBending needles ØDefect in manufacture ØSudden unexpected movement

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

Management §Keep calm §Do not move §Remove it with small hemostat if a visible part is present If not ØInform the patient ØRefer to oral surgeon for consultation ØIn general if retrieval is difficult allow to remain

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

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

Persistent anesthesia or parasthesia (cont. . ) Management v. Most parasthesias resolve within approximately 8 weeks without treatment v. It depends on the degree of damage v. Most commonly involved the tongue then the lower lip v. 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.

3) Facial nerve paralysis ØBranches ØCauses; IANB & Akinosi

Problem ØCosmetic: Unable to voluntarily close one eye Prevention Management ØReassurance ØContact lenses should be removed ØAn eye patch should be applied

4) Trismus ØDefinition ØCauses §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 ØProblem §Limitation of movement §Pain in the acute phase §Scar formation in the chronic phase

Management of trismus v. 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 v. Patients usually report improvement within 2 -3 days v. Therapy should be continued until the patient is free of symptoms v. If trismus and pain continue beyond 2 days consider the possibility of infection. Antibiotics should be added to the treatment regimen for 7 days v. Complete recovery takes about 7 weeks(4 -20 weeks) v. If no improvement is noted , the patient should be referred to oral surgeon for evaluation ØTMJ involvement is rare in the first 4 -6 weeks after injection, so surgery may be indicated ØIf continued dental care in the area is urgent Akinosi is indicated

Wooden spatula in use to improve trismus

5) Soft-tissue injury ØCauses ØProblem

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

6) Hematoma v. Causes v. Problem Trismus, pain, Swelling, discoloration v. 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

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

7) Intra-vascular injection: Accidental intra-venous injection may produce dramatic systemic effects: 1) Visual disturbances: Ø 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; Ø Diplopia: Due to accidental intravascular injection causing loss of motor function to the muscles of orbit. 2) Aural disturbances: Hearing loss due to LA. reaching the Internal auditory artery following intra-arterial injection 3) 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.

8) Pain on injection causes I. Pain during injection Ø Pain at the time of injection is mainly due to poor technique and may be caused by the following: 1) Intraepithelial injection: This cause epithelial ballooning and is overcome by insertion of the needle into the sub-mucosa. 2) Sub-periosteal injection: The discomfort is due to injection into non-compliant tissue.

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: Ø PH: The presence of Adrenaline increase injection sensation due to the law PH (burning sensation). Ø Temperature: Cold solutions cause pain; should be allowed to reach room temperature before injection. Ø Contamination of the LA cartridges

II. Post-injection pain Ø Pain after the effects of the LA. have disappeared may be caused by: 1) Sub-periosteal injection: This is the result of stripping of the periosteum off the bone. 2) Forceful intraligamentary anesthesia: This may produce extrusion of a tooth leading to traumatic occlusion. Problem: Ø Increases patients’ anxiety Ø Sudden unexpected movement Ø Tissue damage Ø Trismus, parasthesia, edema

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

10) Edema Causes ØTrauma ØInfection ØHemorrhage ØInjection of irritating solution ØAllergy: angioedema ØHereditary angioedema Problem ØIf sever: life threatening situation Management ØNon-allergy or LA- induced edema ØAllergy-induced edema (angioneurotic edema)

11) Postanesthetic intraoral lesions Causes, Problem, Management 1) Reassurance 2) Viscous lidocaine 3) Orabase without Kenalog Ø The ulcerations usually last for 7 -10 days with or without treatment