Post-traumatic Neuropathy and Burning Mouth Syndrome


Procedure

Recovery rate

Reference

Third molar surgery

IANI – 67 %; LNI – 72 % Buccal access TMS

LIN – lingual access TMS 88 %

[8]

[26] (90 %)

[6])

Mandibular fractures

IANI – 91 %

[3]

Orthognathic surgery

IANI – 97 %

BSSO IANI (patients are quoted 8–20 %)

[17]

Local anaesthesia inferior dental block (mainly Lidocaine)

25 %

[35]

Implant-related IANI

Complete recovery – 50 %

Partial recovery – 44 %

No change – 6 %

[19]


A review of common operations such as groin hernia repair, breast and thoracic surgery, leg amputation, and coronary artery bypass surgery found an incidence of chronic post-surgical pain in 10–50 % of patients [20]





22.1.6 Management of Iatrogenic Trigeminal Nerve Damage


The management will depend on the mechanism (Table 22.2) and the duration of the nerve injury and the patients’ complaints. Many injuries have limited benefit from surgical intervention and should be managed symptomatically. Earlier intervention is required for endodontic, implant and third molar-related nerve injuries as discussed.


Table 22.2
Timing and management of trigeminal nerve injury































Event

Duration

Endo

<24–48 h surgery

Implant

<24–48 h surgery

Wisdom teeth – Inferior alveolar nerve injury

<2 weeks surgery

Wisdom teeth – Lingual nerve injury

>3– months surgery

Local anaesthetic nerve injuries (LN or IAN)

Therapeutic management only

Orthognathic nerve injuries

Therapeutic management only

Mandibular fracture nerve injuries

Therapeutic management only


A known or suspected sectioned/damaged nerve should undergo immediate exploration repair

If there is a persistent large neuropathic area (>40 % dermatome) then a severe nerve injury is present. If pain and/or hypersensitivity are present these will often be the main precipitating factors of difficulty with daily function. These symptoms may not be best treated using surgical intervention, however the patient’s inability to cope with disability and pain, is often the driving factor.

Prevention is the key as no management strategy guarantees resolution of nerve injury in relation to implants. Timing of intervention is summarised in Table 22.2.

Management of LA, orthognathic surgery and trauma-related injuries is essentially by counselling and medication for pain if present; however, prevention is better than cure. Valid consent will ensure that the patient understands the surgical risks and consequences when nerve injury occurs. Reassurance of the patient and giving them realistic expectations of recovery is suggested. Iatrogenic nerve injuries will require treatment in the



  • Acute phase (within 30 h)


  • Or Late phase


22.1.6.1 Acute Phase


There may be a limited window to maximise inferior alveolar nerve injury resolution in relation to dental implants, endodontics and mandibular wisdom teeth. A report illustrated that early removal of implants (within 30 h) may maximise neuropathy resolution, however the evidence remains weak [21].

The suggested protocol based upon available evidence includes:



  • HOMECHECK – The treating clinician must contact the patient between 6 and 24 h after surgery (Homecheck) to establish any persistent neuropathy after LA has resolved. (This builds on the relationship of the clinician with the patient that will be premised upon good consent process.)


  • Confirm the presence of neuropathy. If the neuropathy affects most of the dermatome +/− associated with severe neuropathic pain nerve injury must be suspected.


  • Say SORRY. This is NOT an admission of guilt.


  • Additional scanning or radiography is not essential.


  • Initiate medical management.



    • High dose oral NSAIDs (600–800 mgs Ibuprofen PO QDS)


    • GMP prescription for Prednisolone 5-day step-down dose 50–40–30–20–10 mg PO (not for patients with contraindications for steroids or NSAIDs)


  • Prompt removal of the implant to maximise potential resolution of the nerve injury is advised.


  • Review patient and report CQC


22.1.6.2 Late Phase


After 3–7 days nerve injury is likely to be permanent and therapeutic management is indicated. With patients presenting with IAN neuropathy late postoperatively the author no longer removes implant similar to other specialists (Pogrel A, personal communication), as it appears to be of little value in reversing nerve damage and associated symptoms.

Overall management of patients with iatrogenic trigeminal nerve injury

Management options for post-traumatic neuropathy will depend upon the mechanism, duration of injury and the patients’ wishes. Management options include;



  • Reassurance and review


  • Medical management – early intervention for minimising neural inflammation (steroids, NSAIDs, although the protocol is not evidence-based) and pain management or for the management of depression


  • Counselling


  • Surgery

The clinician must discern exactly what need to be addressed based upon the patients;



  • Disability


  • Can’t cope!

The planned treatment must address the patients’ concerns appropriately and the aims of treatment would ideally provide:



  • Improved function: Treatment will NOT restore function completely


  • To improve sensation: Treatment will NEVER restore normal sensation


  • To reduce pain or altered sensation: The neuropathic pain can be managed using antiepileptic drugs if the pain is neuralgic, tricyclic antidepressants if the pain is constant and burning in nature or external local anaesthetic patches if the lip is very sensitive to touch or change in temperature.


22.1.7 Summary of Possible Management Tools




1.

Timing of intervention and mechanism of injury are paramount in decision making in treatment of trigeminal nerve injuries.

 

2.

Counselling is the most useful tool for managing patients with permanent sensory problematic nerve injuries.

 

3.

Medical symptomatic therapy is indicated for patients with pain or discomfort and for patients with anxiety and/or depression in relation to chronic pain. But due to the extensive side effects of chronic pain medication, less than 8 % of patients remain on medication



  • Topical agents for pain (Versatis Patches topical Lidocaine 5 % 12 h on and 12 h off) [22]


  • Systemic agents for pain [11]



    • Tricyclic antidepressants (Amitriptyline and nortriptyline)


    • Antiepileptics (Pregabalin or Gabapentin) [46]

 

4.

Surgical exploration



  • Immediate repair if nerve section is known


  • Remove implant within 24 h (ideally)


  • Explore IAN injuries is no longer indicated for nerve injuries older than 4 weeks


  • Exploratory surgery for lingual nerve injuries within 3 months post-injury [43, 44]

 

None of these interventions ‘fix’ the patient, but the aim is to manage their symptoms as best as possible, often not very satisfactorily. The prospect of lifelong neuropathic pain combined with functional difficulties and the psychological impact of the iatrogenesis is often a significant challenge for any patient and clinician to manage.



22.2 Burning Mouth Syndrome


Burning mouth syndrome is a rare but impactful condition affecting mainly post-menopausal women resulting in constant pain and significant daily difficulty with eating, drinking and daily function. The aetiology of BMS remains an enigma. Recent evidence suggests a likely neuropathic pain, the cause of which remains unknown. There is no cure for this condition and the unfortunate patients remain managed on a variety of neuropathic pain analgesics, salivary substitutes and other non-medical interventions that help the patient ‘get through the day’.

Burning sensations in the mouth can result from a variety of causes including oral candidiasis, lichen planus, allergies, oral galvanism, xerostomia, systemic diseases like diabetes, deficiencies in vitamin B12, folic acid or iron, hormonal changes and autoimmune disease. In these cases, the term secondary burning mouth syndrome is used [9, 42]. The burning sensations may then subside if the primary cause is managed successfully. Primary Burning Mouth Syndrome (BMS), in which none of these potential etiological factors are present, is considered a neuropathic pain condition.
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Jul 22, 2016 | Posted by in PHARMACY | Comments Off on Post-traumatic Neuropathy and Burning Mouth Syndrome

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