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Local and Regional Anesthesia: Dentistry and Oral Surgery 1131

Local and Regional Anesthesia: Dentistry and Oral Surgery Client Education
Sheet
VetBooks.ir Procedure

• Repeating nerve blocks possible (consider-
Difficulty level: ♦
ing total maximum dosage and length of Local anesthesia:
Overview and Goals procedure) • Topical gels: application of anesthetic gel
• Saving medical expenses by reducing the onto mucosal surfaces; short-lived effects
concentration needed of an inhalation Possible Complications and • Splash block (wound irrigation): dropping of
anesthetic Common Errors to Avoid local anesthetic solution (0.05-0.1 mL/kg in
• Minimizing complications from hypotension, Iatrogenic failure: cats and 0.1-0.2 mL/kg in dogs of a mixture
bradycardia, and hypoventilation • Overdose (calculate correct dosage) of 0.25 mL phenylephrine 1% and 50 mL
• Enabling faster recovery with fewer • Injection into vessel lumen (aspirate before lidocaine 2%) onto a wound; for example,
complications injecting, stop and withdraw if blood; oth- into nasal cavity after maxillectomy before
• Providing analgesia in postoperative period erwise, keep needle steady during injection) or through nostrils after surgical closure Procedures and Techniques
• Vessel laceration (apply digital pressure with • Intraligamentous injection: into the peri-
Indications gauze if occurs; avoid bending of needle tip odontal ligament; cumbersome
Procedures in dentistry, oral and maxillofacial on bone) • Injection near planned incision: around
surgery • Hematoma (apply digital pressure with gauze surgical site
if occurs) Regional anesthesia: select one or more sites
Contraindications • Infection (use sterile equipment for each depending on location of lesion/intervention.
• History of allergy to a local anesthetic injection site) • Maxillary nerve block
agent • Nerve damage (inject lowest effective volume; ○ Intraoral: insert needle through oral
• Bleeding disorder (risk of hematoma forma- reinsert needle if abnormal resistance to injec- mucosa just caudal to last maxillary
tion and ischemic nerve damage) tion is felt [possible intrafascicular placement molar, and advance it in a dorsal direc-
• Pre-existing peripheral neuropathy (risk of of needle tip]) tion (maxillary nerve enters infraorbital
permanent nerve damage) • Ocular trauma (avoid advancing needle too canal through maxillary foramen); slightly
• Infection at needle insertion site/pathway dorsal when blocking the maxillary nerve, bending the needle 7-9 mm from its tip
• Inflammation at injection site (altering effect and keep needle parallel to the hard palate facilitates block placement and indicates
of anesthetic agent) when blocking the infraorbital nerve) how deep needle is placed.
Self-mutilation: ○ Extraoral: insert needle through skin of the
Equipment, Anesthesia • Pawing at mouth (consider placing e-collar) caudal cheek, and advance it in a medial
• Usually performed under general anesthesia • Biting on lip/cheek (after preoperative or and slightly dorsal direction (caudal to
• Needles: 1 4 to 1 2 inches long (3-3.5 cm) postoperative presence of malocclusion) maxilla, ventral to zygomatic arch, and
1
1
(depending on depth of penetration), 22- to • Biting on tongue (desensitization of tongue rostral to mandibular ramus).
27-gauge (depending on whether going after inferior alveolar nerve block unlikely ○ Areas desensitized: incisive bone, maxilla
through skin or mucosa) on 1- to 3-mL when proper technique employed) and palatine bone, all maxillary teeth on
syringes (depending on volume injected)
• Bupivacaine 0.5% (effective for up to 6-8
hours); lidocaine 2% (effective for up to 2
hours); onset time for analgesia longer with
long-acting local anesthetics (few minutes for
lidocaine, up to 15 minutes for bupivacaine)
Anticipated Time
1-2 minutes per block (including calculating
dosage, preparing syringe/needle, and injecting
local anesthetic)

Preparation: Important
Checkpoints A B
Calculate total maximum dosages:
• Bupivacaine 2 mg/kg in cats and dogs
• Lidocaine 5 mg/kg in dogs, 1 mg/kg
in cats
• 0.5% solution contains 5 mg/mL and 2%
solution contains 20 mg/mL
• To benefit from both local anesthetics (i.e.,
short onset time and long acting), one can
mix 0.2 mL lidocaine 2% with 0.8 mL
bupivacaine 0.5% per 4.53 kg (10 lb) as
maximum patient dosage.
Consider how many jaw quadrants (sites) need C D
nerve blocks:
• Depending on oral examination findings LOCAL AND REGIONAL ANESTHESIA: DENTISTRY AND ORAL SURGERY Skull (A) and cadaver
• Volumes per site of 0.2 (cats/small dogs) to (B) show infraorbital nerve block in a dog. Skull (C) and cadaver (D) show inferior alveolar nerve block in a
0.8 mL (large dogs) often sufficiently effective dog. (Copyright Dr. Alexander M. Reiter.)

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