Complications of LA

1. LOCAL COMPLICATIONS OF
LOCAL ANESTHESIA
PRESENTED BY
KELSY VARGHESE
REG NO: 150021659
IIIBDS (2015 BATCH)

2. POTENTIAL COMPLICATIONS
• Needle breakage
• Persistent anesthesia/Paresthesia
• Facial nerve paralysis
• Truisms
• Soft tissue injury
• Hematoma
• Pain on injection
• Burning on injection
• Infection
• Enema
• Sloughing of tissues
• Postanesthetic intraoral lesions

3. NEEDLE BREAKAGE

4. CAUSES
• Weakening of the dental needle by bending it
before the insertion into the patient’s mouth.
• Sudden unexpected movement by the patient
as the needle penetrates muscle or contacts
the periosteum.

5. PROBLEMS
• If a broken needle can be retrieved without
surgical interventions, no emergency exists.
• Needles that break off within tissues and
cannot be readily retrieved do not migrate
more than a few millimeters.

6. • They become encased in scar tissue within a few
weeks.
• Eelcting to leave the needle fragment in the tissue
instead of attempting its removal usually leads to
fewer problems.

7. PREVENTION
• Use larger gauge needles for techniques
requiring penetration of significant depths of
soft tissue, 25-gauge needles are appropriate
for an IA, mandibular, PSA, ASA, maxillary
nerve block.
• Use long needles for injections requiring
penetration of significant (>18mm)depths of
soft tissues

8. • Do not insert a needle into tissues to its hub,
unless it is absolutely essential
• Do not redirect a needle once it is inserted
into tissues. Excessive lateral force on the
needle is a factor in breakage.

9. MANAGEMENT
• When a needle breaks:
– Remain calm, do not panic
– Instruct the pt not to move. Do not remove your
hand from the pts mouth, keep the pts mouth
open.
If available place a bite block in the pts mouth
– If the fragment is visible try to remove it with a
small hemostat or a Magill intubation forceps.

10. • If the needle is not visible and cannot be readily
retrieved:
• Do not proceed with an incision or probing
• Calmly inform the pt, attempt to allay fears
• Note the incident on the pts chart. Keep the
remaining needle fragment.
• Refer the pt to an oral and maxillofacial surgeon
for consultation, not for removal of the needle.

11. • When a needle breaks, consideration should be given to its
immediate removal, under the following conditions:
• The needle is superficial and easily located thorough
radiological and clinical examination, removal by a
competent dental surgeon is possible.
• Despite its superficial location, attempted retrieval is
unsuccessful within a reasonable length of time, then the
attempt is abandoned and allow the needle fragment to
remain.
• The needle is located in deeper tissues or is hard to locate it
should be permitted to remain without an attempt at
removal.

12. PERSISTENT ANESTHESIA OR
PARESTHESIA
PARESTHESIA is defined as persistent anesthesia or
altered sensation well beyond the expected duration
of anesthesia. The definition should also include
byperesthesia and dysesthesia, in which the pt
experience both pain and numbness.

13. CAUSES
• Trauma
• Postoperative lingual nerve Paresthesia and
inferior alveolar nerve Paresthesia was
common in pts under 20yrs.

14. • Injection of a local anesthetic contaminated by alcohol or
sterilizing soln near a nerve produces irritation, resulting in
edema and increased pressure in the region of the nerve, leaing
to paresthesia.
• Trauma to a nerve sheath can be produced by the needle during
injection.
• The pt reports the sensation of “electric shock” throughout
the distribution of the involved nerve
• Insertion of needle into the foramen as in 2nd division
maxillary nerve block through the greater palatine foramen,
also increases the likelihood of nerve injury.

15. • Hemorrhage into or around the neural sheath. Bleeding
increases pressure on the nerve leading to paresthesia.
• The local anesthetic soln itself may contribute to the
development of paresthesia after local anesthetic injection.
• Mostly reported cases were of the lingual nerve or the
inferior alveolar nerve or both with anesthesia of tongue
followed by anesthesia of lip.
• Pain was reported
• Paresthesia was reported after administration of 4%local
anesthetic, either prilocaine HCl and articaine HCl

16. PROBLEMS
• Self inflicted injury
• Biting or thermal insults can occur without a
pts awareness until progressed to a serious
degree.

17. • When the lingual nerve is involved the sense of taste(via the
chorda tympani nerve) is impaired.
• Hyperesthesia – an increased sensitivity to noxious stimuli
• Dysesthesia - painful sensation occurring to usually
nonnoxious stimuli

18. PREVENTION
• Strict adherence to injection protocol and
proper care and handling of dental cartridges
help minimize the risk of paresthesia

19. MANAGEMENT
• In pts with persistent sensory deficit:
– Be reassuring. The pt usually telephones the office
the day after the dental procedure complaining of
still being a little numb.
• Speak with the pt personally! Do not relegate the duty
to an auxiliary. Remember if pts cannot get through to
speak to the doctor, they can always get the doctors
attention through litigation.

20. • Explain that paresthesia is not uncommon after
local anesthetic administration.
• Arrange an appointment to examine the pt.
• Record the incident on the dental chart.

21. • Examine the pt.
• Determine the degree and extent of paresthesia.
• Explain to the pt that paresthesia usually lasts for
atleast 2mnths before resolution begins and that it
may last upto a year or longer.
• “Tincture of time” is the recommended medicine.
• Record all findings on the pts chart.

22. • Reschedule the pt for examination every 2mnths for as long as
the sensory deficit persists.
• If the sensory deficit last even after 1yr then the pt should be
consulted to an oral surgeon or neurologist. Consultation
should be done earlier if the pt or doctor considers it prudent.
• Dental treatment may continue, but avoid readministrating
local anesthetic into the region of prvsly traumatized nerve.

23. FACIAL NERVE PARALYSIS

24. INNERVATION OF FACIAL NERVE
• Temporal branches
– Frontalis
– Orbicularis oculi
– Corrugator supercili
• Zygomatic branches
– Orbicularis oculi
• Buccal branches
– Procerus
– Zygomaticus
– Levator labii superioris
– Buccinator
– Orbiculaaris oris
• Mandibular branch
– Depressor anguli oris
– Depressor labii inferioris
– Mentalis

26. CAUSES
• Commonly caused by the introduction of local
anesthetic into the capsule of the parotid gland,
which is located at the posterior border of the
mandibular ramus, clothed by the medial
pterygoid and the masseter muscles.
• Directing the needle posteriorly or inadvertently
deflecting it in a posterior direction during an
IANB or overinsertion during a Vazirani-Akinosi
nerve block may place the tip of the needle
within the body of the parotid gland.

27. PROBLEMS
• Loss of motor function to the muscles of facial
expressions.
• The primary problem associated with
transient facial nerve paralysis is cosmetic
• The persons face appears lopsided

28. • Secondary problem is that the pt is unable to
voluntarily close one eye.
• The protective lid reflex of the eye is abolished.
• Winking and blinking becomes impossible.
• The cornea does its innervation, if it is irritated, the
corneal reflex is intact and tears lubricate the eye.

29. PREVENTION
• Always preventable by adhering to the IANB and
Vazirani-Akinosi nerve block.
• If the needle deflects posteriorly during IANB and
bone is not contacted the needle should be
withdrawn almost entirely from the soft tissues
the barrel of the syringe brought posteriorly and
the needle readvanced until it contacts the bone.
• Because there is no contact with bone during the
Vazirani-Akinosi nerve block, overinsertion of the
needle either absolute or relative should be
avoided, if possible

30. MANAGEMENT
• Reassure the pt.
– Explain that the situation is transient, will last for a
few hours, and will resolve without residual effect.
– Mention that it is produced by the normal
reaction to local anesthetic drugs on the facial
nerve, which is motor nerve to the muscles of
facial expression.

31. • Contact lenses should be removed until muscular movement
returns
• An eye patch should be applied to the affected eye until
muscle tone returns.
• If resistance is offered by the pt to manually close the
lower eyelid periodically to keep the keep the cornea
lubricated.
• Record the incident on the pts chart.
• Although there is no contraindication in reanesthetizing the
pt to achieve mandibular anesthesia, it may be prudent to
forego further dental care at this appointment.

32. TRISMUS
A prolonged tetanic spasm of the jaw muscles by
which the normal opening of the mouth is restricted.

33. CAUSES
• Trauma to muscles or blood vessels in the
infratemporal fossa.
• Local anesthetic soln in which alcohol or cold
sterilizing soln have diffused produce irritation of
tissues, leading potentially to trismus.
• Local anesthetics have slight mycotoxic properties
on skeletal muscles.
– The injection of local anesthetics either
intramuscularly or supramuscularly leads to rapidly
progressive necrosis of the exposed muscle fibre.

34. • Hemorrhage
• Large vol of extravascular blood can produce
tissue irritation, leading to muscle dysfunction as
the blood is slowly resorbed.
• A low grade infection after injection can also cause
trismus.
• Multiple needle penetrations correlate with a
greater incidence of postinjection trismus.
• Excessive vol of local anesthetic soln deposited into a
restricted area produce distension of tissues, which
may lead to postinjection trismus.
• This is more common after multiple missed IANBs.

35. PROBLEMS
• The avg interincisal opening in cases of
trismus is 13.7mm
• In the acute phase of trismus, pain
produced by hemmoraghe leads to
muscle spasm and limitation of
movement.

36. • The second or chronic, phase usually develops if
treatment is not begun.
• Chronic hypomobility is secondary to organization
of the hematoma, with subsequent fibrosis and
scar contracture.
• Infection also may produce hypomobility through
increased pain, increased tissue reaction, and
scarring.

37. PREVENTION
• Use a sharp, sterile, disposable needle.
• Properly care for and handle dental local
anesthetic cartridges.
• Use aseptic technique. Contaminated needles
should be changed immediately.

38. • Practice atraumatic insertion and injection technique.
• Avoid repeat injections and multiple insertions into the
same area through knowledge of anatomy and proper
technique. Use regional nerve blocks instead of local
infiltration wherever possible and rational.
• Use minimum effective volumes of local anesthetic.
TRISMUS IS NOT ALWAYS PREVENTABLE.

39. MANAGEMENT
• With mild pain and dysfunction the pt reports
minimum difficulty opening his or her mouth.
– Arrange an appointment for examination.
– In the interim prescribe heat therapy, warm saline
rinses, analgesics and if necessary, muscle
relaxants to manage the initial phase of muscle
spasm.

40. • Heat therapy consists of applying hot, moist towels to the affected area for
approx 20min ever hour.
• For a warm saline rinse, a teaspoon of salt is added to a 12-ounce glass of warm
water and held in the mouth on the involved side to help relieve the discomfort
of trismus.
• Aspirin(325mg) is usually adequate as an analgesic in managing pain associated
with trismus.
• Codeine(30-60mg Q6H) may be necessary if the discomfort is more intense.
• Diazepam(10mg BD)is used for muscle relaxation.
• The pt should be advised initiate physiotherapy consisting of opening and
closing the mouth, as well as lateral excursions of the mandible for 5min every
3-4hrs.
• Chewing gum provides lateral movement of the tempromandibular joint.
• Record the incident findings and treatment on the pts dental chart.

41. • The Vazirani-Akinosi mandibular nerve block usually provides relief of the motor
dysfunction, permitting the pt to open his or her mouth and allow the
administration of the appropriate injection for clinical pain control, if needed.
• Pts with trismus related to intraoral injections improve within 48-72hrs.
• If pain and dysfunction continue unabated beyond 48hrs, consider the
possibility of infection.
• Antibiotics should be added to the treatment regimen described and continued
7 full days.
• Complete recovery from injection related trismus takes about 6wks, with
arrange of 4-20wks.
• For severe pain or dysfunction if no improvement is noted within 2-3days
without antibiotics or if the ability to open the mouth has become limited, the
pt should be referred to an oral and maxillofacial surgeon for evaluation.
• Surgical intervention to correct chronic dysfunction may be indicated in some
instances.

42. SOFT TISSUE INJURY

43. CAUSES
• Trauma occurs most frequently in younger
children and in mentally or physically disabled
children or adults.
• Primary cause is the soft tissue anesthesia
lasts for than pulpal anesthesia.

44. PROBLEMS
• Swelling
• Pain
• Young child or handicapped individual may have
difficulty in coping up with the situation and
cause behavioural problems.
• Infection may develop in most instances

45. PREVENTION
• A local anesthetic of appropriate duration should be selected if dental
appointments are brief.
• A cotton roll can be placed b/w the lips and teeth if they are still
anesthetized at the time of discharge.
• Secure the roll with dental floss wrapped around the tooth.
• Warn the pt and guardian against eating, drinking hot fluids, and biting on
the lips or tongue to test for anesthesia
• A self adherent warning sticker may be used on children.
It states, "Watch me, my lips and cheeks are numb.” the sticker is placed on
the forehead of the pt.

46. MANAGEMENT
• Analgesics for pain, as necessary.
• Antibiotics, as necessary, in cases of infection.
• Lukewarm saline rinses to aid in decreasing any
swelling that may be present.
• Petroleum jelly or other lubricant to cover a lip
lesion and minimize irritation.

47. HEMATOMA

48. CAUSES
• Large hematoma may result from either arterial or venous
puncture after posterior superior alveolar or inferior
alveolar nerve blank.
• The tissues surrounding these vessels more readily
accommodate significant vol of blood.
• The blood effuses from vessels until extravascular exceeds
intravascular pressure or clotting factors.
• Hematomas after IANB are visible only intraorally whereas
PSA hematomas are visible extraorally.

49. PROBLEM
• Bruise which may or may not be visible
extraorally.
• Trismus
• Pain
• Swelling and discolouration of the region may
subside within 7-14days.

50. PREVENTION
• Knowledge of the normal anatomy involved in the
proposed injection is important.
– Certain techniques have a greater risk of visible
hematoma.
– The PSANB is the most common followed by the IANB and
the mental/incisive nerve block.
• Modify the injection technique as dictated by the pts
anatomy.
– For e.g.: the depth of penetration for a PSA nerve block
may be decreased in a pt with smaller facial
characteristics.

51. • Use a short needle for the PSA nerve block to decrease the
risk of hematoma.
• Minimize the no of needle penetrations into tissue.
• Never use a needle as a probe in tissues .
HEMATOMA IS NOT ALWAYS PREVENTABLE.

52. MANAGEMENT
• Immediate: when swelling becomes evident during or
immediately after a local anesthetic injection, direct
pressure should be applied to the site of bleeding.
– For most injections the blood vessel lies b/w the skin and
the bones on which pressure should be applied for not less
than 2min. This effectively stops the bleeding.
 Inferior alveolar nerve block. Pressure is applied to the
medial aspect of the mandibular ramus. Clinical
manifestations of the hematoma are intraoral, possible
tissue discolouration and probable tissue swelling on
the medial aspect of the mandibular ramus.

53.  Anterior superior alveolar (infraorbital)nerve block. Pressure is applied to the skin
directly over the infraorbital foramen. Clinical manifestation is discolouration of the
skin below the lower eyelid. Hematoma is unlikely to arise with ASA nerve block
because of the technique described requires application of pressure to the injection
site throughout drug administration and for a period of 2-3min after.
 Incisive(mental)nerve block. Pressure is applied directly over the mental foramen, on
the skin or mucous membrane. Clinical manifestations are discolouration of skin over
the mental foramen or swelling in the mucobuccal fold in the region of the mental
foramen. As with the ASA nerve block, pressure applied during the administration of
the drug effectively minimizes the risk of hematoma formation during incisive nerve
block.
 Buccal nerve block or any palatal injection. Place pressure at the site of bleeding. In
these injections the clinical manifestations of hematoma are usually visible only
within the mouth.
 Posterior superior alveolar nerve block. Produces the largest and most esthetically
unappealing hematoma. The infratemporal fossa into which bleeding occurs can
accommodate a large vol of blood. The hematoma is usually not recognized until a
colourless swelling appears on the side of the face.