COMPLICATIONS OF LA

PRESENTED BY: Dr SHERMIL SAYD

• Broadly classified into two sections– Local complications – Systemic complications

• Local complications– Needle breakage– Paresthesia– Facial nerve paralysis– Trismus– Soft tissue injury– Hematoma– Pain on injection– Burning on injection– Infection– Edema– Sloughing of tissues– Post anesthetic intra oral lesions

Needle breakage

• Rare occurrence now due to the introduction of disposable needles

• Causes:– Weakening of the dental needle by bending– Sudden unexpected movement by the patient,

more likely in pediatric patients– Finer needles are more likely to break – Needles that have been previously bent – Defective manufacturing

• Problem:– Can be left of the in the tissue if its removal will cause

more extensive damage– Infections arising from these needles are very much rare – They usually gets embedded in the scar tissue

• Prevention– Don’t bend the needle– Use thicker needles– Use long needles rather than short ones– Do not insert needles upto its hub– Do not redirect the needle once it is more than halfway

through

• Management1. When a needle breaks

a) Do not panicb) Instruct the patient not to move, keep the hand inside

and mouth openc) If the fragment is visible, remove it

2. If the needle is not visible and not retrievable1. Do not probe or incise2. Calmly inform the patient3. Note the incident on the patients chart4. Refer the patient to an oral surgeon

– Immediate removal of broken needle only if• Needle is superficial and easily located through the

radiological and clinical examination• If the attempt proves t be futile for a considerable

amount of time, then the needle should be left as it is• The needle is located in deeper tissues, then it should

be allowed to remain there without an attempt

Paresthesia

• Defn: persistent anesthesia or altered sensation well beyond the expected duration of anesthesia

• Causes: – Trauma to the nerve– Injection of the LA solution contaminated with alcohol( they

are also neurolytic and may cause long term damage to the nerve

– Trauma to the nerve sheath during the insertion of the needle– Insertion of a needle in to the foramen – Hemorrhage around the nerve sheath– LA solution itself(haas and lennon-1993)

• Problems:– Can lead to self inflicted injury– Sense of taste impaired, LN involvement

• Prevention:– Strict adherence to the injection protocol

• Management:– Be reassuring

• Speak to the patient personally• Explain• Appointment to examine the patient• Record the incident in the dental chart

– Examine the patient• Determine the extent and the degree• Explain to the patient that it may persist for upto 1 year• Tincture of time- reccommended medicine• Record all the findings

– Reschedule the patient for examination every two months

– If sensory deficit present more than one year, consultation with a neurologist is recommended

– Dental treatment may be continued, but avoid injecting the LA solution into the same region again

Facial nerve paralysis

• Cause:– Introduction of the LA solution into the parotid capsule– Directing the needle inadvertently posteriorly during IANB– Over insertion during vazirani akinosi

• Problem:– Loss of motor function of the muscles of facial expression– Usually transitory– Minimal sensory loss– Unilateral facial paralysis- face appears lopsided– Unable to close the eye o the affected side

• Prevention:– Adhere to the protocol– Over insertion during vazirani akinosi should be avoided when

possible• Management

– Reassure the patient– Contact lenses should be removed until muscular movements

return– An eye patch should be given for the eye on the affected side– Record in chart– Although there is no contraindication for reanesthesia, it will be

prudent at this point

Trismus

• Prolonged tetanic spasm of the jaws by which normal opening of the mouth is restricted

• Causes: – Trauma to the muscles or blood vessels in the

infratemporal fossa– Contaminated LA solution being injected into the site– Injection of LA IM or supramuscularly– Hemorrhage– Low grade infection after injection– Multiple needle penetration

• Problem– The average interincisal opening is

13.7mm(range5-23mm)– Acute phase- leads to muscle spasm and limitation

of movement– Chronic hypomobility associated with organization

of the hematoma, with subsequent fibrosis and scar contracture

• Prevention– Use a sharp, sterile, disposable needle– Properly care for and handle dental LA catridges– Use aseptic technique– Practice atraumatic insertion and injection

technique– Avoid repeat injections– Use minimum effective volumes of LA

• Management– With mild pain and dysfunction the patient

reports minimum difficulty opening the mouth– The patient should be prescribed with heat

therapy, warm saline rinses, analgesics and if necessary muscle relaxants

– The patient should be advised to initiate physiotherapy consisting of opening and closing of the mouth

– Sugarless chewing gums can also be prescribed

• If the needed dental treatment in the affected area is urgent, then alternate techniques like vazirani akinosi technique can be used

• Usually there I will be an improvement after after24-48hrs

• Therapy should be continued until the patient is free of symptoms

• If the pain and dysfunction continues abate 48hrs, then infection should be suspected and antibiotics should be added into the regimen

• Other therapies which include ultrasound or appliances also can be used in these situations

• Surgical interventions may be necessary to correct the chronic dysfunction

Soft-tissue injury

• Self inflicted trauma to the lips and tongue is frequently caused by the patient inadvertently biting o chewing these tissues while still anesthetized

• Cause: – Common in children, physically and mentally

disabled– It occurs due to the prolonged anesthesia of the

soft tissues than that of the pulp

• Problem: – Trauma to anesthetized tissues can lead to swelling

and significant pain when the anesthetic effect resolves– Remote instances of development of infection

• Prevention:– A cotton roll can be placed between the lips and the

teeth secured with floss wrapped around the teeth– Warn the patients guardian about this– A self adherent warning sticker can be used on children

on their forehead

• Management– Analgesics for pain as necessary– Antibiotics as necessary– Lukewarm saline rinses to reduce the swelling and

pain– Petroleum jelly to cover up the lip lesion

Hematoma

• The effusion of blood into extravascular space is called as hematoma

• Cause– A large hematoma may develop from either arterial or

venous puncture following a PSA or IA nerve block– The tissues surrounding this vessels more readily

accommodate significant volumes of blood and continues to do so until clot forms

– IANB hematomas are visible only intraorally while PSA hematomas are visible extraorally

• Problems:– Includes pain and trismus– Swelling and discoloration usually subsides within 7-14

days• Prevention:

– Knowledge of normal anatomy– Modify the injection technique based upon the patients

anatomy– Use a short needle for PSA to reduce the risk of hematoma – Minimize the number of needle penetrations into tissue– Never use a needle as a probe in tissues

• Management:– Immediate:

• When swelling becomes evident during the injection, pressure should be applied over the area, for not less than 2 mins

• For IANB, pressure applied onto the medial aspect of the ramus• For ASA, pressure is applied on the skin directly over the

infraorbital foramen• For mental nerve block, placed directly over the mental foramen• Buccal nerve block or palatal injection, at the site of bleeding• For PSA, digital pressure applied in the mucobuccal fold as far

distally as possible. Icepack extraorally

– Subsequent:• Advise the patient about the possible soreness and

limitation of the movement• If soreness develops, advise analgesics• Heat may be applied to the area from the next day

onwards to increase the rate of resorption of the clot• Tincture of time is the most important factor in the

management of trauma

Pain on injection

• Causes:– Careless injection technique– A needle can become dull from multiple injections– Rapid deposition of the anesthetic solution may

cause tissue damage– Needles with barbs also cause pain

• Problem:– Can lead to increase in patient anxiety and may lead

sudden and unexpected movement increasing the risk of needle breakage

• Prevention:– Proper technique of injection– Use sharp needles– Use topical anesthetic before injection– Use sterile local anesthetic solution– Inject slowly– Be certain that the temperature of the solution is

correct

• Management:– No management necessary

Burning on injection

• Causes:– Primary cause is the pH of the solution– Rapid injection of the local anesthetic solution– Contaminated local anesthetic solution– Solution warmed to body temperature are

considered too hot by the patient• Problems:– Although transient, may lead to postanesthetic

trismus, edema, or possible paresthesia

• Prevention:– Slow injection,1ml/min. recommended rate of

1.8ml/min should not be exceeded– Cartridge should be stored at room temperature

• Management:– No immideate management necessary

Infection

• Cause:– Contamination of the needle before

administration – Improper technique in handling the LA equipment– Injecting the LA solution into an area of infection

• Problem:– Can cause infection and lead to trismus

• Prevention:– Use sterile disposable needles– Proper care for handling of the needles and catridges– Properly prepare the tissues before injection

Management:• Immediate treatment consists of antibiotics and

analgesics, muscle relaxant if needed and physiotherapy• Antibiotics should be started for a 7-10 day course• Penicillin is the drug of choice and erythromycin, if

allergic to penicillin

Edema

• Causes:– Trauma during injection– Infection– Allergy – Hemorrhage– Injection of irritating solution– Hereditary angioedema

• Problem:– Angioneurotic edema produced can cause airway

obstruction– Edema of the tongue, larynx or pharynx may develop

and represent a potentially life threatening situation.• Prevention:– Proper handling of the LA armamentarium– Atraumatic injection technique– Complete medical evaluation

• Management– When produced by traumatic injection or

introduction of irritating solutions, edema is of low degree and resolves without any formal therapy

– Analgesics for pain can described– after hemorrhage edema resolves more slowly– Edema due to infection doesn’t subside

spontaneously but may in fact become more progressively more intense if untreated

– Allergy induced edema is potentially life threatening

• If edema causes airway obstruction, then– P- if unconscious, the patient placed supine– A-B-C- BLS administered as required– D- definitive treatment: EMS summoned– Epinephrine is administered: 0.3mg(adult), 0.15mg(child)IM or

IV every 10-15 mins until respiratory distress resolves– Histamine blocker is administered– Corticosteroid IM/IV– Preparation for cricothyrotomy should be done if total airway

obstruction seems to be developing– Patients should be evaluated thoroughly before the next

appointment

Sloughing of tissues

• Causes– Epithelial desquamation:• Application of the topical anesthetic to the gingival

tissues for prolonged period• Heightened sensitivity of tissues to a LA agent• Reaction in an area where a topical has been applied

– Sterile abscess-• Secondary to prolonged ischemia resulting from the

use of LA with vasoconstrictor• Usually develops on hard palate

• Problems:– Pain– Infection in these areas

• Prevention– Use topical anesthetics as recommended– Do not use overly concentrated solutions containing

vasoconstrictor• Management:– No formal management necessary– Symptomatic management

Post anesthetic intraoral lesions

• Cause:– Recurrent apthous stomatitis or herpes simplex can

occur after the injection of the local anesthetic solution– Trauma to tissues by a needle or cotton swabs or any

other instrument may activate the latent form of the disease process that was present in tissues before injection

• Problem:– c/o acute sensitivity in the ulcerated area

• Management:– Primary management- symptomatic– Pain develops after 2 days– No management is necessary if the pain is not

severe– Preparations can be used to reduce the pain and

irritations caused by these lesions

Ocular problems

• signs and symptoms including tissue blanching, hematoma formation, facial paralysis, diplopia, amaurosis, ptosis, mydriasis, miosis, enophthalmos, and even permanent blindness have been reported

• The mechanism of action is not fully understood• Aspiration at the time of administration of local

anesthesia is very important and minimizes the risk of ocular complications.

• When ocular complications persist, an ophthalmology consultation is prudent

Systemic complications

• Caused by adverse drug reaction.• There are mainly three types of complications– Allergic reactions– Toxicity– Methemoglobinemia

Allergic reactions

• Allergic reactions due to the administration of local anesthesia are uncommon but can occur

• There are a few different tests that can be used by the allergist to document an allergy to local anesthesia, such as the skin prick test, the interdermal or subcutaneous placements test, and/or the drug provocative challenge test(gold standard)

• Allergies to local anesthetic may be type I or type IV hypersensitivity reactions, with the type I response more commonly reported

• type I– symptoms include skin manifestations (erythema,

pruritus, urticaria), gastrointestinal manifestations (muscle cramping, nausea and vomiting, incon-tinence), respiratory manifestations (coughing, wheezing, dyspnea, laryngeal edema), and cardio-vascular manifestations (palpitations, tachycardia, hypotension, unconsciousness, cardiac arrest)

• Treatment – depends on the severity of the reaction. – Mild- managed by oral or intramuscular

antihistamines, such as diphenhydramine, 25 to 50 mg.– If serious signs or symptoms develop, immediate

treatment becomes necessary, and this includes basic life support, intramuscular or subcutaneous epineph-rine 0.3 to 0.5 mg, and activating the emergency response system for transportation to the local hospital for acute therapy.51

Toxicity

• Toxicity can be caused by excessive dosing of either the local anesthetic or the vasoconstrictor

• Cause:– inadvertent intravascular injection– repeated injections of the local anesthetic– excessive volumes are used in pediatric dentistry

• Prevention– Adhering to local anesthetic dosing guidelines– simple way to calculate maximum safe dosages for

all anesthetic formulations used in dentistry is called the rule of 25, which states that a dentist may safely use 1 cartridge(1.8ml) of any local anesthetic for every 11.4 kg (25 lbs) of patient weight

• Phases of toxicity– excitatory phase-manifest as tremors, muscle twitching,

shivering, and clonic tonic convulsions– generalized central nervous system depression and possible

life-threatening respiratory depression– With extremely high doses, cardiac excitability and cardiac

conduction decrease and leads to ectopic rhythms, bradycardia and ensuing peripheral vasodilation, and significant hypotension.

– Treatment should address respiratory depression and convulsions. Vital signs should be monitored, the airway maintained, basic life support administered, and the emergency medical support services should be called. Intravenous diazepam or midazolam may be administered for a seizure that does not stop

Methemoglobinemia

• Methemoglobinemia is a reaction that can occur after administration of amide local anesthetics, nitrates

• Prilocaine and benzocaine are used in dentistry and may induce methemoglobinemia

• Signs and symptoms usually do not appear for 3 to 4 hours after the administration of large doses of local anesthesia

• Clinical signs of cyanosis are observed when blood levels of methemoglobin reach 10% to 20%, and dyspnea and tachycardia are observed when methemoglobin levels reach 35% to 40%

• 55 Co-oximetry is a conventional pulse oximetry that measures the methemoglobin and carboxyhemoglobin levels

• Treatment– Methylene blue 1 to 2 mg/kg intravenously is used

for the treatment of methemoglobinemia.

summary

• Local anesthetics are a routine part in all oral and maxillofacial practices. Minimizing adverse outcomes is the goal of all practitioners. This goal can be accom-plished by using the appropriate local anes-thetics in certain situations

• Malamed SF. Handbook of local anesthesia. 5th edition. Philadelphia: Elsevier Mosby; 2004.

• R david, Complications of Local Anesthesia Used in Oral and Maxillofacial Surgery: Oral Maxillofacial Surg Clin N Am 23 (2011) 369–377

• Pogrel MA, Thamby S. Permanent nerve involve-ment resulting from inferior alveolar nerve blocks. J Am Dent Assoc 2004;131:901–7.

• Local anesthesia, monheims