Complications of third molar removal (trigeminal nerve damage) Flashcards
Minor complications of third molar removal (9)
– Pain, swelling, trismus – Infection – Fracture – Bleeding and bruising – TMJ problems – Temporary nerve damage – Periodontal problems – Damage to other teeth – Oral-antral communication
Pain after third molar removal (3)
Guaranteed after surgical removal of lower 3rd molars -can be severe Pre-op -warn patient -advise on analgesics
Swelling and trismus after third molar removal (3)
Guaranteed after surgical removal of lower 3rd molars
-variable but can be marked
Pre-op
-warn patient
-provide advice on how to minimise (NSAIDs)
Infection after third molar removal (5)
Difficult to assess incidence as diagnosis not always
straightforward
– higher incidence of postop infection in lower third molar sockets
– good oral hygiene post-operatively
– no good evidence for routine use of antibiotics
– consider all the variables – antibiotics have a role (co-morbidity, local and systemic)
Damage to adjacent teeth after third molar removal (3)
- Mobilisation of second molars
- Damage to restorations
- Fracture of adjacent teeth
Damage to adjacent teeth after third molar removal - pre-op (3)
– Assess clinically and radiographically
– Warn patient
– Have plan in place to minimise risk and deal with complication
Fractured mandible (4)
• Elderly, edentulous patients with atrophic mandible • Pre-existing bone pathology • Large bone defects • Excessive use of force (cryers, large elevators)
Displacement of third molars (2)
Upper 8’s
– Oral-antral communication
– Fractured tuberosity
see maxillary antrum lecture
Trigeminal nerve injuries after third molar removal (3)
Trigeminal nerve injuries occur commonly in Oral Surgery
Usually during removal of wisdom teeth
Also implantology, trauma, soft tissue surgery
Prevalence of nerve damage after third molar removal (4)
IAN • Temporary 5-7% • Permanent 0.5% - 1% Lingual • Temporary 3-7% • Permanent 0.3-0.5% -minimum 300 lingual nerve injuries a year, more IAN
Aetiology of trigeminal nerve damage (6)
- Third Molar (majority)
- Implantology
- Other surgery, e.g orthognathic
- Trauma
- Needle Stick (neuropraxia)
- Endodontics
Why so many nerve injuries? (3)
- Mainly drill injuries
- Still lingual flaps being raised
- Increase lingual nerve injuries – coronectomy?
The effect of trigeminal nerve injury (5)
Complete loss of sensation to half the anterior tongue and/ or chin/ lip
Paraesthesia - reduced sensation
Dysaesthesia - pain, tingling, burning
Allodynia (painful response to non-painful stimuli
Loss of taste
What do the patients with nerve injuries complain of? (9)
Pain, unpleasant burning and tingling They feel as if they are dribbling They bite their lip Avoid eating in public Don’t enjoy kissing Bite their tongue ‘Tongue feels like a large lump of jelly’ ‘Lose food’ under their tongue Don’t enjoy food
Surgical technique for lingual nerve injuries (7)
Lingual flap raised and lingual periosteum divided
The central and distal nerves stumps identified and mobilised
The damaged segment of nerve (4-14mm mean 9.5mm) was excised
Direct reapposition with 5-10 (mean 7) 8/0 ethilon epineurial sutures
All patients given dexamethasone and antibiotics
Initial study prospective, quantitative assessment of 53 patients pre-op and >12 months post-op
Now have >200 patients, with larger growing database of outcomes following treatment
Outcomes measured for lingual nerve injuries (6)
Light touch Pin prick Two point discrimination Gustatory response Altered sensation – dysaesthesia Subjective assessment
Is lingual nerve repair effective (5)
Majority of patients regain some sensation
Fewer patients tend to bite their tongue
Significant improvement was shown in tests using
-light touch stimuli
-pin prick stimuli
-gustatory stimuli
-two point discrimination
Patients consider it worthwhile
Remember – It will never return to normal
Inferior alveolar nerve injury (3)
Mainly due to proximity to lower third molars
Increasing amount due to implant placement
Some from trauma
Management of IAN following third molar removal (8)
The nerve is usually well supported in the mandibular canal
Even after transection the ends do not usually retract
Primary repair is not normally required
Control bleeding with temporary packing with gauze
AVOID
Diathermy
Whitehead’s varnish and other medicaments
Surgicel
Bone wax
Injuries from implantology (6)
Can be from drill or implant Many drills longer than implant length -'y' dimension (can be 1.5mm) Overdrilling -low resistance bone - slippage of drill -missing at roof of canal Miscalculation of position of IAN Immediate placement (primary stability) - more likely to cause IAN Safety zone - 2-4mm
Mental foramen area - high risk (2)
Mental foramen – 4mm anterior to ensure avoidance of anterior loop.
Consider surgical exposure
Intraoperative factors of implant injury (5)
‘Sudden give’
‘Electric shock’
Arterial bleed – large percentage of injuries – secondary to haematoma
May be sensible to wait 2 days and then place implant – avoid compression ischemia
No evidence though!
Management post-injury from implant - evidence and short-term (7)
Good evidence that neural recovery with implant related injuries, inversely proportional to time
Ideally remove implant within 24 – 36 hours
Postoperative call – same day or following day
Short-term remove implant
Inform patient
Take radiograph for localisation of lesion
Evaluate – time elapsed, proximity of implant etc
Neurosensory evaluation
Indications for surgical intervention (2)
Persistent anaesthesia
Dysaesthesia/Pain
IAN decompression / neurolysis (5)
Cannot excise complete segment Can remove bony obstruction Can remove bony compression Can remove remove soft tissue tethering/tension Can remove ‘neuroma’ - dysaesthesia
Direct trauma from LA (3)
Face bevel laterally
?Hypothetical but consider with multiple injections
Most nerve injuries caused by LA injection - multiple injections
How to minimise nerve damage (6)
IAN injuries usually ‘drill injuries’ Some are crush injuries – following forceps extraction Low threshold for sectioning Avoid forceps Elevator removal preferable Avoid lingual flaps
Radiographic assessment of impaction (7)
Type of impaction
Depth of tooth within bone
Crown form
Root form and number
Coronal or root pathology
Other pathology (cyst, caries in 2nd molar)
Relationship with mandibular canal (IAN) or maxillary sinus
Assessment of IAN on radiograph (5)
A:Radiolucency B:Deviation/Constriction C:Loss of cortication D:Deviation of roots E:Narrowing of roots
CT for third molar removal (3)
Not routinely indicated
May be appropriate in high risk cases
CBCT
Coronectomy - to do or not to do (4)
Controversial Pros and cons Lower risk..... Second procedure.... Medico-legal issue Should document discussed with pt if high risk of IAN damage Pt choice
