Tongue Numbness - Post-XLA

Question 1

You have performed surgical XLA on unerupted disto-angular lower 8. Returns the next day with tongue numbness. What structure has been disturbed?

Answer 1

Lingual nerve

Question 2

Describe anatomy of lingual nerve in related to LL8?

Answer 2

Lingual nerve is a division of mandibular branch of trig menial nerve
Responsible for sensory innervation of lingual gingiva, floor of mouth and ipsilateral 2/3rd of tongue
Carries taste fibre to tongue

Question 3

Why can lingual nerve be damaged during XLA?

Answer 3

Lingual nerve vulnerable to iatrogenic damage as runs within lingual mucosa adjacent third molar tooth at level of alveolar crest (or higher)

Question 4

What are the 3 different ways nerves can be damaged?

Answer 4

1.Mechanical - bur/ stretching mucosa/ LA needle
2. Chemical - LA
3. Ischaemic - nerve constricted by reapproximation

Question 5

What is a way to assess 8s difficulty pre-XLA?

Answer 5

Depth of impaction - Pell and Gregory
Relationship of ramus to tooth
Angulation oof tooth - Winter

Question 6

What is Depth of impaction?

Answer 6

A = in line w/ occlusal plane = fully erupted
B = slightly below occlusal plane = PE
C = significantly below occlusal plane

Question 7

What is assessment of relationship to Ramus?

Answer 7

Class I - ramus distal to crown
Class II - ramus in line with crown
Class II - ramus mesial to crown

Question 8

What are different types of angulation?

Answer 8

Vertical
Mesio-angular
Horizontal
Disto-angular

Question 9

What’s risks should be given for 8s XLA?

Answer 9

General - pain, swelling, bleeding, brushing, infection, damage to adjacent teeth
Specific - damage to IAN, damage to LN and adjacent teeth

Question 10

What is incident of lingual nerve damage?

Answer 10

between 0.2-2%
Damage more likely to be temporary

Question 11

How should lingual nerve damage be managed?

Answer 11

Depends on percieved mechanism of injury and post-injury presentation

Question 12

What to do it witness injury or is open injury?

Answer 12

Immediate referral to surgeon w/ experience in miconeurosurgical repair for early intervention

Question 13

How to manage pt who returns w/ nerve damage?

Answer 13

Review, if no improvement referral warranted

Question 14

How are pt assessed/ tx for nerve damage in secondary care setting?

Answer 14

Neurosensory testing
Delayed exploration and repair is considered in some cases

Question 15

Pt had nerve damage > 6 months, can repair be done?

Answer 15

if no sensation 6 month post-injury, recovery is unlikely

Question 16

What can clinicians do to reduced lingual damage?

Answer 16

Pre-op assessment
Lingual retraction - curved, non sharp instrument
Tooth sectioning - drill buccal (split w/ elevator lingually)
Bone removal not on lingual aspect
Suture - small bites lingual mucosa