Timothy J. Eviston

Bell's palsy: aetiology, clinical features and multidisciplinary care

Bells palsy is a common cranial neuropathy causing acute unilateral lower motor neuron facial paralysis. Immune, infective and ischaemic mechanisms are all potential contributors to the development of Bells palsy, but the precise cause remains unclear. Advancements in the understanding of intra-axonal signal molecules and the molecular mechanisms underpinning Wallerian degeneration may further delineate its pathogenesis along with in vitro studies of virus–axon interactions. Recently published guidelines for the acute treatment of Bells palsy advocate for steroid monotherapy, although controversy exists over whether combined corticosteroids and antivirals may possibly have a beneficial role in select cases of severe Bells palsy. For those with longstanding sequaelae from incomplete recovery, aesthetic, functional (nasal patency, eye closure, speech and swallowing) and psychological considerations need to be addressed by the treating team. Increasingly, multidisciplinary collaboration between interested clinicians from a wide variety of subspecialties has proven effective. A patient centred approach utilising physiotherapy, targeted botulinum toxin injection and selective surgical intervention has reduced the burden of long-term disability in facial palsy.

Salivary duct carcinoma: Clinicopathologic features, morphologic spectrum, and somatic mutations.

Accurate diagnosis of salivary duct carcinoma requires a high index of suspicion and clinicopathologic correlation. Hallmark genetic changes that may provide novel therapeutic options are being explored.

Mammary analogue secretory carcinoma: an evaluation of its clinicopathological and genetic characteristics

Summary Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland malignancy. We evaluate the clinicopathological characteristics and long-term clinical behaviour of MASCs. A total of 190 primary salivary gland malignancies at a single institution were reviewed along with relevant immunohistochemical and fluorescent in situ hybridisation (FISH) studies to identify MASCs. Nine MASCs were identified predominantly in the parotid with an equal incidence in men and women and mean age of 36 years. The tumour size ranged from 14 to 50 mm (mean 22 mm). MASCs were composed of monotonous cells with vacuolated eosinophilic cytoplasm and a small nucleus with a distinctive nucleolus. All cases showed immunoreactivity with S-100, MUC4, CK7 and mammoglobin, and lacked immunoreactivity with DOG1, p63, CK5/6 and calponin. ETV6 rearrangement was seen in all cases. No mutations were identified using the OncoCarta Panel v1.0 Kit. Follow up was available for 0.4 to 22 years (median 4 years). Intraparotid lymph node involvement and local recurrence were seen in one patient each. There were no distant metastases. MASCs have specific histopathological features and immunohistochemical profile that distinguish them from their mimics. FISH plays a confirmatory role. An indolent long-term clinical course was observed in this cohort despite involvement of intraparotid lymph node and microscopically involved/close margins.

Diagnostic and prognostic utility of Mastermind-like 2 (MAML2) gene rearrangement detection by fluorescent in situ hybridization (FISH) in mucoepidermoid carcinoma of the salivary glands.

OBJECTIVE Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy, with a proportion harboring MAML2 rearrangement. This study evaluates the diagnostic and prognostic utility of MAML2 rearrangement in MEC. STUDY DESIGN Salivary gland malignancies at a single institution (1989-2014) were reviewed to identify MECs. Histopathologic evaluation, immunohistochemistry, and fluorescent in situ hybridization (FISH) were performed. RESULTS Forty-one cases of MEC were identified, with mean age of 47 years and mean tumor size of 21 mm. Seven locoregional recurrences and five MEC-related deaths were seen over a 22-year follow-up period. Thirty-eight cases were suitable for FISH, and 31 (82%) cases were positive for MAML2 rearrangement, including the oncocytic and clear cell variants of MEC. FISH was negative in the morphologic mimics of MEC. MAML2 rearrangement was significantly associated with longer survival. CONCLUSIONS MAML2 rearrangement is common and specific for MEC, which makes it a useful diagnostic tool. MAML2 rearrangement also predicts a favorable prognosis.

Single innervated segmented vastus lateralis for midfacial reanimation during radical parotidectomy

Innervated free muscle transfer using the gracilis muscle or temporalis myoplasty has been successfully utilized for facial reanimation in chronic facial palsy. These techniques are less suited to immediate facial reconstruction in the setting of radical parotidectomy, in which the complexity of the defect, patient age, postoperative radiotherapy, and limited life expectancy pose particular challenges.

Assessment of axonal excitability properties in two branches of the human facial nerve.

BACKGROUND Axonal excitability methods have an established role in determining the biophysical properties of human axons in the clinical setting. The translation and refinement of these techniques for application to the facial nerve is important for advancing the pathophysiological understanding of facial nerve disorders. Facial nerve disorders are common and debilitating, yet in most cases diagnosis is based on clinical judgment alone. The pathophysiology of most causes of facial palsy remains unclear. NEW METHOD Novel techniques for the acquisition of facial nerve excitability properties were developed based on anatomical and surgical landmarks for two facial nerve branches. Zygomatic branch stimulation with nasalis recording and marginal mandibular branch stimulation with depressor angularis oris (DAO) recording were used. Comparisons were made between the two branches and with the median nerve, and the relationship between gender, age and nerve properties was explored through subgroup analysis. RESULTS A full set of recordings were obtained in all participants across a wide age range. 27 nasalis recordings and 19 DAO recordings were completed and analysed. The studies were well tolerated in all participants. Excitability parameters were found to be similar for both branches of the facial nerve. COMPARISON WITH EXISTING METHOD Axonal excitability has proven to be of significant value in the study of motor and sensory neuropathy, however previous experience with facial nerve techniques has been limited. This study establishes normative data and a consistent technique for the application of axonal excitability testing to the study of facial nerve properties.

Validation of the Clinician-Graded Electronic Facial Paralysis Assessment

Background: Facial paralysis remains a debilitating condition despite advances in medical, surgical, and adjunctive interventions. Established grading systems used to assess facial paralysis and interventional outcomes have well-described limitations. The Electronic Facial Paralysis Assessment, a clinician-graded zone-based facial function scale, has recently emerged as a grading tool that may provide greater sensitivity when assessing incomplete paralysis and postsurgical improvement. The authors perform the first comprehensive validation of this tool. Methods: Video recordings of 83 facial paralysis patients were assessed. Grading was performed in two sittings by three individuals with varying degrees of experience in assessing facial paralysis. Interobserver reliability; intraobserver reliability; administration time; and agreement with the Facial Disability Index, House-Brackmann, Sunnybrook, and Sydney facial grading systems were assessed. Results: The Electronic Facial Paralysis Assessment demonstrated high intra observer and interobserver reliability (intraclass correlation coefficient, 0.84 to 0.91 and 0.81 to 0.83, respectively). It correlated well with the House-Brackmann, Sunnybrook, and Sydney facial grading systems (Spearman rho, 0.73, 0.77 and 0.77, respectively). In subdomain analysis, it correlated well with the Sunnybrook and Sydney systems in dynamic movement (Spearman rho, 0.90 and 0.89, respectively) and synkinesis (Spearman rho, range 0.74 and 0.72, respectively). It had poor agreement with the Facial Disability Index (Spearman rho, 0.25). The mean time to complete the tool was 116 ± 61 seconds. Conclusions: The Electronic Facial Paralysis Assessment is a valid facial assessment tool with high reliability and correlation with the established facial paralysis grading systems. It also provides an efficient and detailed analysis of paralysis according to each facial zone. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, II.

Dual chimeric innervated vastus lateralis free flap for single stage blink and midface reanimation

The immediate reconstruction of the face in the setting of radical parotidectomy for malignancy represents a particular challenge. We present a novel technique using 2 sections of the vastus lateralis muscle as a chimeric flap in combination with the anterolateral thigh (ALT) fasciocutaneous flap to achieve midface reanimation and eye closure after radical parotidectomy.

Altered axonal excitability properties in facial palsy

Introduction: Axonal excitability measures give insight into the biophysical properties of peripheral nerve axons. In this study we applied these techniques to the study of facial palsy. Methods: Thirty patients with established facial palsy due to unresolved Bells palsy or herpes zoster (>6 months duration), tumor invasion of the facial nerve, or traumatic facial nerve injury were assessed using facial nerve excitability techniques. Results: Full recordings were obtained in 23 patients (15 unrecovered Bells palsy or herpes zoster, 5 trauma, 3 tumor‐related). Compared with normal controls, the facial palsy group demonstrated changes in stimulus response properties, threshold electrotonus, refractoriness, superexcitability, and I/V slope. Depolarizing threshold electrotonus distinguished between viral and non‐viral etiologies on subgroup analysis. Discussion: In this cross‐sectional study, established facial palsy demonstrated findings similar to those seen in studies of regenerated axons. The improved understanding of underlying axonal characteristics offered by the technique may guide future treatment. Muscle Nerve 57: 268–272, 2018

Creating eye closure in patients with facial nerve paralysis using an implantable solenoid actuator.

This paper proposes the use of an implantable solenoid actuator to create a more natural eyelid closure over current lid loading therapies in patients with facial nerve paralysis (FNP). The actuator works by moving a magnet when a solenoid is activated. This is used to tension a sling applied to the upper eyelid which closes the eye. The sling design has been described elsewhere and creating eye closure using it requires a force of 627 (± 128) mN over a movement of approximately 6 mm. The actuator described here was able to successfully achieve these parameters and repeatedly perform eyelid closure in a cadaveric rabbit model. Device limitations and future improvements have also been identified and discussed.