Complications of Bimaxillary Orthognathic Surgery

Dr N.J. Rutherford

Associate Professor A.C.H. Smith

Definitions

Bimaxillary surgery involves orthognathic procedures on both the mandible and maxillaGenerally these procedures are the Le Fort I osteotomy and the Bilateral Sagittal Split osteotomyOther procedures may include genioplasty and rhinoplasty

Historical Perspective

In the last twenty years bimaxillary surgery has become accepted as a relatively safe procedurePrior to this complications were more frequent due to the following Poor instrumentation Lack of scientific studies Poor techniques Prolonged procedures Traditional methods of fixation Anaesthetic related problems

Complications

All surgical procedures have complications and morbiditiesMost complications are prevented by planning and awarenessIf you never do surgery, you never get surgical complicationsIf you do enough surgery you will have complicationsThe aim is to minimise incidence of morbidity

Complications

Systemic

Local

Preoperative

Intraoperative

Postoperative Short Term Long Term

Systemic

Cardiovascular / Renal Hypovolaemia Shock Stroke Acute Renal Failure

Respiratory Airway Compromise Aspiration Atelectasis Pneumonia

Systemic

Anaesthetic Related Anaphylaxis Malignant Hyperthermia Drug Toxicity

Pain

Psychiatric Body Dysmorphic Disorder Conversion Disorder

Local

As discussed in following slides

Balance of the orthodontic treatment objective and surgical treatment objective

Preoperative

Inadequate planningCephalometrics ImpressionsFacebow/articulatorModel surgerySurgical Wafers

Operative

Failure to achieve the surgical objectiveHaemorrhageMaxilla Devascularization Inability to mobilize maxilla Inability to reduce vertical height Unfavourable osteotomy pattern Condylar distraction Nasal septum deviation

Operative

Mandible Inappropriate split

Buccal plate fracture Lingual plate Fracture Condylar split

Inferior alveolar nerve Nerve in proximal segment Neuropraxia, Neuronometsis, Axonometsis

Facial Nerve Lingual Nerve

Operative

Mandible Inadequate external oblique ridge

reductionDamage to dental and related structures

Operative

Fixation problems Inadequate Fixation Large osteotomy gaps Inadequate bony apposition Inadequate condylar position

Soft tissue Injuries Lips, cheeks, nose

Damage to surrounding structuresImmediate relapse

Postoperative Short Term

Cardiovascular Secondary Haemorrhage Avascular Necrosis maxillary segments Haematoma formation

Infection

Bone Healing / Fixation Failed Fixation Delayed Union Mal / Nonunion

Postoperative Short Term

Early Relapse Poor fixation Unstable final postion Condylar sag Idiopathic Condylar Resorption

Extrusion of teethNeuronal Deficit Paraesthesia, anaesthesia, dysaesthesia,

hyperaesthesia

Postoperative Long Term

Relapse

Fixation Exposure / Infection

T.M.J. Pain

Neuronal Deficits

Patient Disatisfaction

Reducing Complications

Adequate Planning Listen to the patient concerns Set realistic goals for treatment Communication with orthodontist

Accuracy of preoperative work up Assessment of growth Models Articulation Model surgery

Reducing Complications

Meticulous SurgeryGood instrumentationAssistanceAdequate forceCareful dissection

Consider Autologous blood donation

Careful postoperative followup