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An Update on the Causes, Assessment and Management of Third Division

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An Update on the Causes, Assessment and Management of Third Division An update on the causes, IN BRIEF • Provides a history and examination of patients presenting with trigeminal PRACTICE assessment and management of neuropathy to facilitate clinicians in their assessment. • Reviews the literature demonstrating the differing causes of trigeminal neuropathy. third division sensory trigeminal • Presents a case series to outline the causes seen in our nerve injury clinic. • Highlights the importance of identifying neuropathies red flag symptoms for neoplasia. E. Carter,*1 Z. Yilmaz,2 M. Devine2 and T. Renton2 VERIFIABLE CPD PAPER Introduction Sensory neuropathies of the mandibular division of the trigeminal (V3) nerve can be debilitating, causing difficulty with daily function. It has a variety of causes, including iatrogenic injury, usually caused by third molar removal, local anaesthetic administration, implant placement or endodontic treatment. Non-iatrogenic causes include infection, primary or secondary neoplasia and various medical conditions. Objective To review the aetiology, evaluation and man- agement of V3 neuropathy in a retrospective case-series of patients referred to a specialist nerve injury clinic over an eight-year period, particularly focusing on the non-iatrogenic causes of this presentation. Methods A retrospective analy- sis of the case notes of 372 patients referred to the specialist nerve injury clinic between 2006 and 2014 was carried out to establish the cause of the neuropathy and subsequent management or referral. The assessment protocol of trigeminal neuropathy used in the clinic is also outlined. Results Most patients (89.5%) presented with neuropathy due to iatrogenic injury. Of the non-iatrogenic causes (10.5%), malignancy accounted for a fifth of presentations, and infection almost two- fifths, demonstrating the importance of prompt identification of a cause and management by the clinician, or referral to the appropriate specialty. Other, more rare causes are also presented, including multiple sclerosis, sickle-cell anaemia and Paget’s disease, highlighting the importance to the clinician of considering differential diagnoses. Conclusions This case series demonstrates the less frequent, but nevertheless important, non-iatrogenic causes which clinicians should consider when assessing patients with trigeminal neuropathy. INTRODUCTION nerve) or a combination of these symptoms. area more difficult to tolerate compared with Sensory neuropathy of the mandibular divi- other parts of the body.4 Consequences include The aims of this article are to review the pos- sion of the trigeminal nerve (V3) in particu- interference with daily social function, eating, sible causes of mandibular division trigeminal lar has been termed ‘numb chin syndrome,’1,2 drinking, speaking, kissing, applying makeup, (V3) sensory neuropathies, present a retrospec- which is an umbrella term encompassing a tive case series of patients presenting with such range of aetiologies including iatrogenesis, neuropathy and describe recommended evalu- infection, metabolic, degenerative, inflam- ation and management of these patients. matory, trauma and neoplasia.3 Sensory neuropathy is altered sensory The trigeminal nerve is the 5th and larg- perception in the distribution of a nerve, est cranial nerve, and is a mixed motor and presenting as anaesthesia (complete loss of sensory nerve. It is the ‘protector’ sensory sensation), paraesthesia (altered sensation), system for the head and neck and the larger dysaesthesia (unpleasant sensation), neuro- sensory part forms the opthalmic, maxillary pathic pain (pain in the distribution of the and mandibular branches that carry affer- ents sensitive to external or internal stimuli from the skin, muscles, and joints of the face 1The Royal London Hospital, Oral and Maxillofacial Sur- gery Department, Turner Street, London, E1 1BB; 2King’s and mouth, and from the teeth (Fig. 1). The College London Dental Institute, Oral Surgery, Denmark mandibular branch is the only branch with a Opthalmic division Hill Campus, Bessemer Road, London, SE5 9RS motor component, which supplies the mus- *Correspondence to: E. Carter Maxillary division cles of mastication (Table1). Email: [email protected] Mandibular division The impact of trigeminal neuropathy must Refereed Paper not be underestimated. The face has one of Accepted 4 May 2016 the highest concentrations of sensory inner- Fig. 1 Lateral view of the head and neck DOI: 10.1038/sj.bdj.2016.444 depicting the areas innervated by V /V /V ©British Dental Journal 2016; 220: 627-635 vation, making sensory neuropathy in this 1 2 3 BRITISH DENTAL JOURNAL VOLUME 220 NO. 12 JUN 24 2016 627 ©2016 Mac millan Publishers Li mited. All ri ghts reserved. PRACTICE 5–7 shaving and sleeping; all functions that we Other traumatic iatrogenic causes of trigemi- V3 injury as a complication of implant take for granted and are the basis for socia- nal neuropathy include radiotherapy15 and treatment is becoming a major concern12,26,27 bility and life enhancement. Patients usually exposure to chemical agents such as trichlo- and incidence studies indicate a complica- expect and experience significant improve- roethylene, stilbamidine, and allopurinol.16 It tion rate not to be ignored.28,29 There are rare ments in jaw function, dental, facial, and has been shown that the use of whiteheads reports of resolution of implant related V3 overall body image following oral rehabili- varnish and surgicel have temporary effects neuropathies at over four years,30 but these 8 31 tation. V3 sensory neuropathy has a signifi- on peripheral neural function, and Carnoy’s are the exception rather than the norm. cant negative effect on the patient’s quality solution may have a permanent effect,17 this Many authors recommend referral of these of life and when the cause is iatrogenic, the has most relevance in surgery performed in injuries within four months,7,32 but this may psychological effects can be compounded.4 the region of the inferior dental nerve. be too late. We now understand that within Causes of V3 sensory neuropathy include; Third molar surgery is a common cause of three months of injury, permanent central iatrogenic (surgical and medical), infections, iatrogenic injury to the mandibular division and peripheral neurological changes occur, neoplasia, systemic pathology and idiopathic of the trigeminal nerve10,18,19 although mod- rendering neurones unlikely to respond to causes. ern management strategies have been found surgical intervention.33 to successfully prevent injuries in high risk V3 sensory neuropathy has also been Iatrogenic - surgical cases.20,21 Following administration of an infe- reported in connection with mandibular A recent study reported that 63% of cases rior dental block injection, the prevalence of atrophy in the older population, particularly 11 of V3 sensory neuropathy were attributed to temporarily impaired lingual and inferior in edentulous individuals. Dentures which previous dental treatment.9 Iatrogenic injuries alveolar nerve function ranges from 0.15– cause compression of the mental nerve in to the mandibular division of the trigeminal 0.54%;6,22 permanent neuropathy is much less those with atrophic mandibles are a known nerve may be caused by a variety of differ- frequent (0.0001–0.01%).6,23 Inferior alveolar cause of paraesthesia in this group.34 ent treatment modalities such as maxillofacial nerve injury occurs in 1 in 14,000 inferior surgery (for example sagittal split osteoto- dental nerve block injections and is usually Iatrogenic medical mies, reduction and fixation of mandibular temporary (75%) but can persist and become Medication related osteonecrosis of the jaw fractures)4 and minor oral surgery (includ- permanent (at three months).24 Likewise, (MRONJ) has also been documented as a 10 3,35 ing third molar removal), implant place- extrusion of endodontic materials or instru- rare cause of V3 sensory neuropathy, with ment,11,12 inferior dental block and mental mentation beyond the apex in the region of removal of necrotic bone and antibiotic block anaesthesia,13 instrumentation beyond the mental foramen or inferior alveolar nerve administration resulting in resolution or the apex, extrusion of irrigation fluid and fill- may cause severe mechanical and chemical improvement of the associated symptoms.36 14 14,25 ing materials during endodontic treatment. injury resulting in V3 sensory neuropathy. In cases of suspected MRONJ related neu- ropathy it is important to rule out a primary Table 1 The trigeminal nerve main divisions (V1, V2 and V3) or metastatic malignancy as many of these patients have been prescribed the medication Cornea for treatment of metastatic disease. Ciliary body Infection Conjunctiva Opthalmic branch V1 Local periapical infection of teeth has (Sensory) Nasal cavity been reported to cause V3 sensory neu- ropathy.9,37–42 Infection-related neuropathy Sinuses has been shown to resolve following non- Skin of eyebrows, forehead, and nose surgical endodontic therapy or extraction of the causative tooth,38,43 supporting the Side of nose theory that pressure caused by an expand- Lower eyelid ing infection and inflammation can cause Maxillary branch V2 (Sensory) paraesthesia. Upper lip Viral infections have also been implicated Maxillary dentition in the development of V3 sensory neuropa- thy, with herpes zoster reactivation rarely Temporal causing neuropathy of the trigeminal nerve. Auricular The ophthalmic division is most commonly affected, however, the maxillary and man- Lower face dibular divisions can also
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