Maxillary and mandibular osteotomy

Maxillary and mandibular osteotomy

Anesthesia type	General
Airway	Nasal ETT (RAE or MLT)
Lines and access	PIV x2 (Large bore IV x1-2) ± Arterial line
Monitors	Standard 5-lead ECG Temperature
Primary anesthetic considerations
Preoperative	Possible airway difficulty given the patient's midface and mandibular abnormalities (comorbidities such as OSA)
Intraoperative	Highly stimulating, painful surgery, bed 90-180, consider TIVA to help with PONV, controlled hypotension (to help minimize bleeding), minimize nausea and coughing during extubation
Postoperative	PONV Monitor airway patency Pain -- multimodal pain control, minimize IV opioids Surgical mouth closure with heavy elastic vs wires (consider having cutting device nearby if needing to urgently open mouth)
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Overview

Indications

Class II-III malocclusion is one of the most common reasons for performing a maxillary and mandibular osteotomies. Severe malocclusion is typically caused by maxillary hypoplasia and is commonly found in patients with orofacial clefts, obstructive sleep apnea (OSA), and maxillary atrophy. Maxillary surgery is required in up to 25% of cleft lip and palate patients.

Surgical Procedure

Both mandible and maxilla may be ‘advanced’, ‘set back,’ or rotated before being fixed into new positions according to the particular skeletal problem. Sagittal split of the mandible and horizontal Le Fort I osteotomy of the maxilla are the most frequently performed procedures. These may be combined with genioplasty, an osteotomy of the mandibular symphysis to improve the profile of the chin. The combination of mandibular and maxillary (‘bi-maxillary’) surgery, though more complex, allows the greatest possible degree of correction.

Other Associated Pathologies

20% of adult population affected by sleep-disordered breathing, with 7-8% with moderate-to-severe OSA. OSA correlated with obesity, metabolic syndrome, systemic and pulmonary hypertension, congestive heart failure, arrhythmias, heart attacks, stroke. STOP-BANG to screen for OSA.

Other ENT pathology may be present in OSA patients (eg septal deviation, laryngotracheomalacia, tonsil and adenoid hypertrophy). OSA patient may show increased sensitivity to opioids and benzodiazepines.

STOP-BANG:

Snore loudly?

Tired during the day?

Observed cessation of breathing during sleep?

Pressure (high blood pressure)?

BMI > 35 kg/m^2?

Age > 50 years?

Neck circumference > 40 cm?

Gender male?

(yes to 0-2 low risk, yes to 3-4 intermediate risk, yes to 5-8 high risk)

Preoperative management

Patient evaluation

System	Considerations
Airway	Patients often have asymmetric/underdeveloped facies (midface, nasal patency, retrognathic jaw) and may also exhibit a small mouth opening and an inability to prognath their jaw Check for predicators of difficult mask ventilation
Neurologic
Cardiovascular	Check for cardiovascular comorbidities, such as systemic and pulmonary hypertension, CHF, cardiac arrhythmias, MI, stroke
Pulmonary
Gastrointestinal	Higher incidence of GERD
Hematologic
Renal
Endocrine
Other

Labs and studies

• CBC, T&S with blood type verification
• ± PT/PTT
• ± T&C (depending on patient factors or greater than average expected blood loss from surgical team)
• Further studies as indicated from H&P and comorbidities
  • If pulmonary issues, may need CXR, ABG, PFTs
  • If cardiac issues, may need ECG or ECHO

Operating room setup

• Airway
  • Nasal ETT
  • Accordion and/or straight connector
  • ± Nasal trumpet
  • ± Fiberscope or VL device
• Bolus line ± fluid warmer connected to largest PIV
• Lower body forced-air warmer
• 2 infusion channels and 2 syringe pumps on a manifold
• Maintenance/Carrier line with flushed octopus connecter

Patient preparation and premedication

• Pretreatment of both nares with Oxymetazoline (Afrin)
• Tylenol PO 15mg/kg (Max: 1g)
• ± Anxiolysis with midazolam (PO or IV) after considering patient preferences and factors
• Aprepitant or scopolamine patch as needed
• Consider antisialagogue dose of glycopyrrolate prior to induction
  • Adult
    • PO Dose: 1-2 mg PO; Parenteral Dose: 0.1-0.2 mg SC/IM/IV (Max: 1-2 mg/dose, 8mg/day)
  • Pediatric
    • PO Dose: 2+ yo: 0.04-0.1 mg/kg PO; Parenteral Dose, 2+ yo: 0.0004-0.01 mg/kg SC/IM/IV (Max: 0.1-0.2 mg/dose, 0.8 mg/day)

Regional and neuraxial techniques

• Mandibular and maxillary nerve blocks performed by the surgeons can be utilized to aid postoperative pain relief

Intraoperative management

Monitoring and access

• Standard ASA monitors
  • Core temperature monitoring likely only available via bladder or rectal given oral or nasal probes are likely to interfere with surgical exposure
• PIV x2 , at least 1 large-bore PIV for resuscitation
• ± Arterial line as needed based on patient-specific factors
• ± BIS, PSI, or raw EEG monitoring

Induction and airway management

• Standard IV induction: lidocaine (1.5 mg/kg), propofol (1-3 mg/kg), ± short acting opiate of choice (Fentanyl, Sufentanil, Alfentanil) and rocuronium (0.6mg/kg)

• Nasal Intubation
  • Consider fiberscopic placement vs DL or VL ± oral manipulation with MaGill forceps
  • Consider dilation with lubricated nasal trumpet (one-size greater than the desired ETT) - this will additionally aid in confirming which nare is most likely to easily accommodate the ETT and allow for change in ETT sizing prior to intubation attempt if there is difficulty
  • Airway typically secured by surgical team with suture before wrapping the patient's head

• Dexamethasone 4-10mg, typically at least (0.1mg/kg with Max: 10mg for post operative pain/swelling)
• ± Tranexamic Acid (TXA) bolus, typically 1 gram or 30mg/kg over 10-15 minutes
• Ancef, weight-based dosing

Positioning

• Supine with neck extended, on foam donut
• Careful eye protection and padding
• One or two arms tucked
• Table is usually turned 90-180 degrees

Maintenance and surgical considerations

• Check ETT to make sure no pressure on nasal ala
• Maintain anesthetic depth with volatile anesthetic ± IV infusions
  • Example setup:
    • Sevoflurane (MAC of ~ 0.5)
    • Dexmedetomidine (0.2-0.4 mcg/kg/min)
    • Short-acting opiate (eg. Sufentanil/Alfentanil) or Ultra-short-acting opiate (Remifentanil)
    • ± Tranexamic Acid (TXA)
    • ± Phenylephrine
    • ± Background propofol for PONV

• Consider higher volume hydration (if tolerated) to prevent PONV
• Discuss with surgical team need for and timing of deliberate hypotension for otherwise healthy young adults to minimize surgical blood loss and need for transfusion
  • if not controlled with a similar IV anesthetic plan as above you may consider other hypotensive agents for as needed example agent listed below:
    • Sodium Nitroprusside or SNP (Infusion), Glyceryl trinitrate or GTN (Infusion), Clonidine (Infusion or bolus), β-blockers (Infusion or bolus), Magnesium (Bolus)
• Redose Acetaminophen as able
• Be vigilant for bradycardia (mediated through the trigeminovagal reflex) throughout the procedure, especially when making the maxillary osteotomies and during the use of mandibular retractors subperiosteally during a mandibular osteotomy as some cases of severe bradycardia and asystole have been documented.

Emergence

• Toradol 0.5 mg/kg, Max: 30 mg
• Zofran
• Reversal with sugammadex
• Ensure removal of all throat packing
• OGT for gastric decompression/removal of surgical bleeding
• Extubate awake and following commands (swallowing in particular)
• Head up or reverse trendelenburg positioning
• Do not suction in the mouth after OGT has been removed
  • Consider instead using a soft suction catheter through contralateral nare

• Expect significant postoperative facial swelling
• Removal of the nasal ETT after Le Fort I osteotomy should be done gently because the sectioned nasal septum may easily be displaced

Postoperative management

Disposition

• PACU -> observation/overnight admission

Pain management

• Tylenol q6h (liquid PO), NSAID (liquid PO), and IV narcotics all used in perioperative setting, continued after discharge
  • Some patients may be excellent candidates for PCAs post-PACU discharge as nursing ratios change and may be recommended for if their pain is particularly difficult to control

• Maxillofacial surgeons typically advise patients to prepare for a prolonged, painful recovery (~six-weeks off) with additional jaw-healing takings up to 2-3 months

Potential complications

• The reported incidence of PONV after orthognathic surgery varies from 7 to 40%, with steroid prophylaxis and up to 83% with no antiemetic prophylaxis
• Airway difficulties/emergencies due to swelling or inability to handle secretions/bleeding
  • Have closure removal devices at bedside at all time
• Hypertension, and risk of associated bleeding
• Damage to ETT during surgery

Procedure variants

	Variant 1	Variant 2
Unique considerations
Position
Surgical time
EBL
Postoperative disposition
Pain management
Potential complications