7. Types of anesthesia in oral and maxillofacial surgery. Premedication and general anesthesia. Flashcards
Types of Anesthesia
- Local
- General
- Neuroleptanasthesia
- Sedation
Premedication in the context of maxillofacial surgeries
- Administration of medications with specific pharmacological actions before surgery or anesthesia
- Enhances patient safety and comfort during the surgical procedure
Factors that influence the selection and dosage of premedication drugs
- Patient’s age
- Weight
- Physical status
- Type of anesthesia
- Level of anxiety and fear
- Pre-existing medical conditions.
How timing of premedication determined
- Factors such as => onset
- Peak effect
- Duration of action
- Route of administration
- Ensures medication =>achieves intended effects at the appropriate time
- Optimises its efficacy in preparing the patient for anesthesia and surgery
Used for learning objectives of premedication
10 A’s
10 A’s for premedication
- Anxiolysis-Relief of anxiety
- Analgesia
- Amnesia of preoperative events
- Antisialogogue effects-reduction in salivary and bronchial secretions
- Anti-emetic effect
- Anti-acid effect-reduction in stomach acid
- Allergies
- Antiautomatic-parasympathetic/Sympathetic reflexes care-Vagolytic actions
- Anaesthetic induction
- Antibiotic regime
Routes of administration for premedication
- Enteral
- Parenteral
Enteral routes of administration
- Oral
- Rectal
Parenteral routes of administration
- Intranasal
- Intramuscular
- Intravenous
Premedication drug groups
- Benzodiazepines
- Opoids
- Barbituates
- Phenothiazines
- Butyrophenones
- Anticholinergics
- Alpha adrenoceptor antagonists
First Cranial nerve
-Olfactory nerve(smell)
Second Cranial nerve
Optic nerve (sight)
Third Cranial nerve
Oculomotor nerve (Orbital muscles for eye movement)
Fourth Cranial nerve
Trochlear nerve (Orbital muscles for eye movement)
Fifth cranial nerve
Trigeminal nerve( Motor: movement of the **jaws** and **muscles of mastication** Sensory: sensation of feeling for the **face, teeth, and periodontal ligaments**, and anterior two thirds of the **tongue**)
Sixth Cranial nerve
Abducens nerve (Orbital muscles for eye movement)
Seventh Cranial nerve
Facial Nerve ( Motor: to the muscles of facial expression
Sensory: taste to anterior two-thirds of tongue
Secretory: to submandibular and sublingual glands)
Eighth Cranial nerve
Auditory Nerve(Sense of hearing, position, and balance)
Tenth Cranial nerve
Vagus nerve( Pharyngeal and laryngeal movements: digestive tract)
Eleventh Cranial Nerve
Accessory nerve(Neck movements: sternocleidomastoid and trapezius muscles)
Twelfth Cranial nerve
Hypoglossal nerve ( Motor: tongue movement (muscles)
Largest cranial nerve
Trigeminal nerve
Trigeminal nerve divisions
- Division I- Ophthalmic
- Division II- Maxillary nerve
- Division III- Mandibular nerve
Ophthalmic and maxillary nerve are
Afferent only(sensory)
Mandibular nerve is
Efferent (motor) and afferent (sensory)
Ophthalmic Nerve origin
exits skull through superior orbital fissure on the superior surface of the orbit
Ophthalmic Nerve branches
- *-Lacrimal nerve** (smallest),
- *-Frontal nerve**(largest )
- Nasociliary nerve
Ophthalmic Nerve sensations
-Touch, pain, pressure
-Skin of upper third of face (forehead and anterior scalp, and the skin around the eyeball, eyelid and nose,
and part of the nasal mucosa)
-Maxillary sinus
Maxillary nerve sensations
touch, pain, pressure, and temperature
The maxillary nerve innervates
- Middle third of face and the palate
- Pulp of all maxillary teeth
The maxillary nerve exists the brain through
Foramen rotundum
Four important branches of the Maxillary nerve
- -Pterygopalatine*
- -Posterior superior alveolar (PSA)*
- -Infraorbital*
- -Zygomatic nerve*
Which branch of the Pterygopalatine Nerve passes through the greater palatine foramen and what does it become?
Descending palatine nerve becomes Greater palatine nerve
Greater palatine nerve innervation
- Mucosa of posterior part of hard palate
- Palatal gingiva of posterior teeth
Nerves that arise posterior to the Greater palatine foramen
Middle and Posterior (lesser) palatine nerves enter the palate through the lesser palatine foramen to spread posteriorly to supply the tonsils and mucosa of the soft palate
Long branch of Pterygopalatine nerve that runs along roof of nasal cavity
- Nasopalatine nerve
- Runs along nasal septum->enters bone of palate->arises in anterior palate through incisive foramen
Nasopalatine nerve Innervates
-Soft tissue of the nasal septum and gingiva
-Palatal soft tissue lingual to the anterior teeth
The right and left nasopalatine nerves combined with the greater palatine nerves innervate
Soft tissues of entire hard palate
-Once in maxillary bone the posterior superior alveolar nerve supplies
-Maxillary molars(except mesiobuccal root of maxillary first molars)
- Alveolar bone
- PDL
- Facial gingiva of maxillary molars
- Mucosa of part of maxillary sinus
- Cheek mucosa next to maxillary molars
Within the infraorbital canal the infraorbital nerve gives off two branches
Middle superior alveolar nerve(MSA) and Anterior superior alveolar nerve (ASA)
Branches of middle superior alveolar nerve supply
- Maxillary premolars and mesiobuccal root of maxillary first molar
- Alveolar bone
- Periodontal ligaments
- Facial gingiva
- In maxillary premolar region and part of maxillary sinus
Second branch given off by the infraorbital nerve while in the infraorbital canal
Anterior superior alveolar nerve
Anterior superior alveolar nerve supplies
- Pulp
- Supporting alveolar bone
- Periodontal ligaments
- Facial gingiva
- Of maxillary anterior teeth and part of maxillary sinus
Infraorbital nerve exits from
Infraorbital foramen
After exiting from the infraorbital foramen, the infraorbital nerve splits into terminal branches that innervate
- Skin and mucosa of side of nose(nasal nerve)
- Skin and mucosa of lower eyelid(palpebral nerve)
- Skin and mucosa of upper lip, facial gingiva of maxillary premolars and facial gingiva of anterior teeth(labial nerve)
The zygomatic nerve supplies
-Skin of temporal region and lower part of orbit
Division III of trigeminal nerve
Mandibular nerve
Mixed nerve (sensory and motor) and only motor portion of trigeminal nerve
Mandibular nerve
Motor fibres of mandibular nerve supply
-8 muscles of mastication
-Mylohyoid muscle
-Anterior belly of the digastric muscle
Sensory fibres of mandibular nerve supply
- Touch, pain, pressure and temperature
- Lower third of face
- Floor of mouth
- Anterior two thirds of tongue(not taste)
- Mandibular teeth
The mandibular nerve exits the neurocranium through
Foramen ovale
Four main branches of mandibular nerve
- Auriculotemporal nerve
- Buccal nerve
- Lingual nerve
- Inferior alveolar nerve
Auriculotemporal nerve supplies
- Pain and proprioception fibres to the TMJ
- Skin of outer ear
- Lateral aspect of skull and cheek
Buccal nerve innervates
-Mucosa and skin of cheek in area of mandibular molars up to corner of mouth
-Sometimes second premolars
Lingual nerve innervation
- Touch, pain, pressure, temperature(not taste)
- Dorsal(top) and ventral(bottom) surface of anterior two thirds of the tongue and adjacent tissues(floor of mouth, inner surface of mandible and lingual gingiva of entire mandible)
Once the Inferior alveolar nerve enters the mandible through the mandibular foramen it is in the
- Mandibular canal
- Gives off dental branches that spread through trabecular bone of mandible
- Enter apical foramen of all mandibular molars and premolars
- Innervates PDL and alveolar processes of those teeth
Within the mandibular canal, the Inferior alveolar nerve splits near the roots of the premolars to become
-Mental and incisive nerves
Incisive nerve supplies
- Mandibular incisor and canine teeth
- Their PDLs and alveolar processes
The mental nerve branch of the Inferior alveolar nerve exits from the body of the mandible through
-Mental foramen
Mental nerve supplies
- Facial gingiva of the mandibular incisors, canines, and premolars
- Mucosa and skin of the lower lip and chin on that side up to the midline
Motor(efferent) branches of mandibular nerve supply to muscles of mastication
- Masseteric nerve-(Masseter muscle and TMJ)
- Posterior and anterior temporal nerves(Temporalis muscle)
- Medial pterygoid nerve(medial pterygoid muscle)
-Lateral pterygoid nerve(lateral pterygoid muscle)
Facial nerve fibres are
Mixed(sensory and motor)
Efferent fibres of facial nerve innervate
- Muscles of facial expression
- Posterior belly of digastric muscle
- Stylohyoid muscle
- Stapedius muscle
Secretory fibres of Facial nerve innervate
-Secretions from Sublingual(Under mucosa in floor of mouth superior to mylohyoid muscle) and Submandibular glands(Located in submandibular fossae on medial surface of mandible inferior to mylohyoid muscle)
The Chorda tympanic fibres of the facial nerve join with
-Lingual nerve and supply sense of taste to anterior two thirds of tongue
The glossopharyngeal nerve type
- Mixed nerve(sensory and motor)
- Supplies parts of tongue and pharynx
Afferent fibres of Glossopharyngeal nerve supply
-Taste and sensation to posterior one third of tongue
-Sensation to mucosa of pharynx and tonsils
Motor nerves of the Glossopharyngeal innervate
Stylopharyngeus muscle of the pharnyx
Secretory fibres of the Glossopharyngeal nerve innervate
Parotid gland
Hypoglossal nerve innervation
- Descends steeply to muscles that move tongue
- Genioglossus, styloglossus, hyoglossus
Inferior Alveolar nerve block -Halstead Technique
- Targets Inferior alveolar nerve
- Anaesthetises
- Teeth and bone on one side of mandible
- Soft tissues on buccal aspect anterior to mental foramen
- Soft tissues of lower lip
- Reflected and attached gingivae from premolar teeth to midline
- Lingual nerve-anterior two thirds of tongue
- Injection at pterygotemporal space on medial aspect of ramus(region of mandibular foramen)
Halstead Technique procedure
- Long 35mm needle no narrower than 27 gauge used
- Patient mouth open wide
- Thumb on coronoid notch
- Index finger extraoral at height of posterior border of ramus
- Syringe passed across lower premolars
- Penetration of syringe between external oblique ridge and pterygomandibular raphae
- Height of penetration halfway between thumbnail
- Advance needle until bone contacted(25mm of needle insertion)
- Withdraw, aspirate and inject 1.5-2 ml of solution
Gow-gates technique
- More superior than Halstead technique(more branches of mandibular nerve affected)
- Anaesthetises inferior alveolar nerve, lingual, long buccal, mylohyoid and auriculotemporal nerves
- Mouth wide open
- Parallel plane between corner of mouth and intertragal notch used as guide
- Syringe passed along maxillary canine of opposite side and across palatal cusps of maxillary second molar on injected side
- When bone of condyle contacted, slight withdraw, aspiration and injection of 2ml solution
- More effective than Halstead approach
Akinosi-Varizani Technique
- Anaesthetises inferior alveolar nerve, Lingual nerve, mylohyoid nerve and occasionally long buccal nerve
- Administered with patients mouth closed
- Long needle no narrower than 27 gauge used
- Syringe introduced intraorally at level of mucogingival junction of maxillary molars
- Syringe advanced to medial surface of ramus where insertion into occurs
- Hub of needle adjacent to distal surface of maxillary second molar→ Needle should be in correct place for injection
- Aspiration and injection of 2ml solution slowly
Mental and incisive nerve block
-Anaesthetises
- teeth and jaws from premolars to anteriors
- Soft tissues of lower lip and chin to midline on one side
- First molar in some cases
- Usually intraoral but extraoral approach can be used
- Needle inserted at depth of buccal sulcus between premolar teeth at apices→ Targeting mental foramen
- 1.5ml solution injected and tissues massaged to encourage entry of solution into foramen
Long buccal nerve block
- Anaesthetises the buccal gingivae and mucosa and part of the cheek in the mandibular molar region
- 0.5ml solution in region of coronoid notch of mandible
Maxillary Nerve block
-Anaesthetises
- Teeth and bone of maxilla on one side
- Buccal and palatal mucosa
- Skin of lower lip, lower eyelid and lateral aspect of the nose
- Intraoral and extraoral approaches
- Intraoral methods-Tuberosity approach and greater palatine foramen approach
Tuberosity approach
- Solution deposited high in buccal sulcus → distal surface of maxillary second molar
- Angle of 45 degrees to depth of 30.. mm
- 2 ml solution deposited
Infraorbital nerve block technique
- ION approached from either intraoral or extraoral sides
- Intraoral approach→ long needle into buccal sulcus(between premolar teeth)
→Advance towards infraorbital foramen(palpated extraorally)
→1-1.5ml solution deposited at 16mm following aspiration
Infraorbital nerve block targets
- Teeth and associated bone from second premolar to central incisor
- Adjacent gingivae of the teeth
- Mucosal and skin of one half of upper lip
- Part of skin of nose affected
Greater palatine foramen approach
- Mouth wide open=> greater palatine foramen identified →depression medial to second maxillary molar) distal surface)
- Insertion into pterygopalatine fossa(via greater palatine foramen)
- Needle angle 45 degrees superiorly and posteriorly to depth of 30 mm
- 2 ml solution injected
Nasopalatine nerve block
- Anaesthetises tissue of hard palate adjacent to incisor teeth
- 0.2-0.5 ml solution adjacent to incisive papilla
Injection in parotid gland results in
-Facial nerve→ Hemifacial paresis
Length of Halstead Anaesthesia
- Teeth→ 45mins
- Soft tissues→ up to 3 hours
Weisbrem technique
- Open mouth as wide as possible
- Syringe on opposite premolars
- Advanced to lateral edge of plica pterygomandibularis(pterygomandibular fold)
- Needle 0.5 cm below chewing surface of maxilllary third or second molar=>
- In absence of teeth 1.5 cm from alveolar crest
- Needle advanced to contact bone, withdrawn, aspiration and injection of 1.5ml
- On withdrawl, rest of solution deposited for lingual nerve
- Anesthesia after 5-7 minutes
Nitrous oxide, and how it functions in dental anesthesia
*Aka laughing gas
* Crosses the alveoli of the lungs and dissolves into the passing blood=> brain
* Dissociated and euphoric feeling
* Used in combination with oxygen.
General anesthesia drugs commonly used in dentistry, and their purpose
- Midazolam
- Ketamine
- Propofol, and fentanyl
- Put a person in a twilight sleep or render them completely unconscious and unaware of pain
Purpose of combining nitrous oxide with oxygen during its administration
- Ensures patient receives an adequate supply of oxygen while experiencing the sedative and euphoric effects of nitrous oxide
