Efficacy and safety of botulinum toxin type A for treatment of Frey's syndrome: evidence from 22 published articles

Guidelines for the Use of Botulinum Toxin in Otolaryngology From the Korean Society of Laryngology, Phoniatrics and Logopedics Guideline Task Force

The Korean Society of Laryngology, Phoniatrics and Logopedics created a task force to establish clinical practice guidelines for the use of botulinum toxin (BT) in otolaryngology. We selected 10 disease categories: spasmodic dysphonia, essential vocal tremor, vocal fold granuloma, bilateral vocal fold paralysis, Frey's syndrome, sialocele, sialorrhea, cricopharyngeal dysfunction, chronic sialadenitis, and first bite syndrome. To retrieve all relevant papers, we searched the CORE databases with predefined search strategies, including Medline (PubMed), Embase, the Cochrane Library, and KoreaMed. The committee reported 13 final recommendations with detailed evidence profiles. The guidelines are primarily aimed at all clinicians applying BT to the head and neck area. In addition, the guidelines aim to promote an improved understanding of the safe and effective use of BT by policymakers and counselors, as well as in patients scheduled to receive BT injections.

Mechanism and clinical use of botulinum neurotoxin in head and facial region

PURPOSE

Botulinum neurotoxin (BoNT) is a biological toxin produced by Clostridium botulinum. BoNT is a potent toxin extensively used in therapeutic interventions. This review provides an updated overview of the mechanisms of action and clinical applications of BoNT in head and facial region.

STUDY SELECTION

MEDLINE/PubMed searches were conducted using the terms "botulinum neurotoxin" and "dentistry" along with a combination of other related terms. In addition, studies were manually selected from reference lists of the selected articles.

RESULTS

The Food and Drug Administration in the United States initially approved BoNT to treat strabismus, blepharospasm, and hemifacial spasms. The use of BoNT in dermatology and cosmetics has been widely established and has created a revolution in these fields. Over the years, its applications in various medical specialties have expanded widely. Owing to its safety, efficacy, and long duration of action, it is well-accepted by patients. BoNT/A and BoNT/B are widely used in clinical practice. Several off-label uses of BoNT in the dental fraternity have yielded promising results. We have elaborated on the speculated mechanism of action, dosage, effective sites of injection, and adverse effects of each therapeutic application. The various clinical indications for BoNT include bruxism, myofascial pain, temporomandibular joint dislocation, hemifacial pain, orofacial dystonia, facial paralysis, chronic migraine, and trigeminal neuralgia.

CONCLUSIONS

BoNT is a safe treatment that can be used effectively, provided that the clinician has adequate knowledge regarding the mechanism, injection techniques, and local and systemic side effects and that it is administered cautiously and purposefully.

The incidence of Frey syndrome and treatment with botulinum toxin in the Central Denmark Region

Objectives

Frey syndrome (FS) is a common complication to large salivary glands surgery. This study primarily aims to describe the incidence of FS among parotid surgery patients in the Central Denmark Region. The secondary aim is to describe predisposing characteristics to syndrome development and the effect of treatment with botulinum toxin (Botox) injection.

Methods

This is a retrospective qualitative study spanning the years 2015-2020. Data on patients diagnosed with FS after parotid surgery with symptoms severe enough to require Botox was extracted from electronic patient records. Incidence of FS development was calculated using data from all parotid gland surgeries in the same period and region.

Results

The incidence of treatment-requiring FS was 2.6% (20/775), with an annual incidence ranging from 0.8% (1/125) in 2017 to 4.5% (5/112) in 2016. Difference in FS development for men and women was not statistically significant (p = .07), although it was significantly more common after total parotidectomy compared to superficial resection (p = .003), and after malignant compared to benign diagnosis (p = .01). Complications in the postoperative period arose for 30% of FS patients. Repeated treatment with Botox was necessary after 6-12 months and at a median interval of 11 months. Forty-five percent of patients received only one injection. The average dose per injection was 48.3 IU.

Conclusion

This study revealed a rather low incidence of FS in the Central Denmark Region compared to current international literature. Total parotidectomy and malignant diagnosis predisposed to syndrome development. Botox injection had a wide-ranging effective duration but typically lasted for around 1 year.

Level of evidence

Level IV.

Botulinum toxin A in dentistry and orofacial surgery: an evidence-based review - part 1: therapeutic applications

Objective An evidence-based review on the safety and efficacy of botulinum toxin type-A (BoNTA) in orofacial conditions, focusing on the therapeutic applications and role of BoNTA as an adjuvant treatment.Data source and selection Data was collected using PubMed (Medline), Cochrane Library of Systematic Reviews and Cochrane Central Register of Controlled Trials electronic databases. Having satisfied the search parameters, 32 studies for therapeutic applications and 26 for BoNTA as an adjunctive treatment were included. The quality of relevant studies was assessed using the Best Evidence Topics (BETs) Critical Appraisal Tool.Data extraction The highest level of evidence (LOE) behind BoNTA safety and efficacy was for wound healing and scar management in the orofacial surgery context, where BoNTA was presented as an adjunctive modality. Level-I evidence was controversial for temporomandibular disorders and bruxism. However, it showed promising results for painful temporomandibular disorders of myogenic origin refractory to conservative therapies, and to decrease muscle contraction intensity in sleeping bruxism. There was only one level-II study for persistent recurrent aphthous stomatitis. Data showed limited level-III evidence for orofacial pain conditions (temporomandibular joint recurrent dislocation and pain, burning mouth syndrome or atypical odontalgia), oral cancer complications, or as an adjuvant to maxillofacial and orthognathic surgeries. Benefits of BoNTA in prosthodontics had weak level-IV evidence. No evidence was found among the periodontology field.Conclusion There is growing evidence to support the safety and efficacy of BoNTA in the investigated orofacial pathological conditions, with high levels of satisfaction from the patient and clinician perspective. However, there are some inconsistencies and limited high-quality evidence available. Well-designed controlled clinical trials are necessary to evaluate long-term safety, efficacy and cost-effectiveness before BoNTA is widely adopted with irrefutable evidence-based clinical guidelines.

Preclinical Evidence for the Role of Botulinum Neurotoxin A (BoNT/A) in the Treatment of Peripheral Nerve Injury

Traumatic peripheral nerve injuries tend to be more common in younger, working age populations and can lead to long-lasting disability. Peripheral nerves have an impressive capacity to regenerate; however, successful recovery after injury depends on a number of factors including the mechanism and severity of the trauma, the distance from injury to the reinnervation target, connective tissue sheath integrity, and delay between injury and treatment. Even though modern surgical procedures have greatly improved the success rate, many peripheral nerve injuries still culminate in persistent neuropathic pain and incomplete functional recovery. Recent studies in animals suggest that botulinum neurotoxin A (BoNT/A) can accelerate nerve regeneration and improve functional recovery after injury to peripheral nerves. Possible mechanisms of BoNT/A action include activation or proliferation of support cells (Schwann cells, mast cells, and macrophages), increased angiogenesis, and improvement of blood flow to regenerating nerves.

Frey's Syndrome: A Review of Aetiology and Treatment

First described by Polish Neurologist Łucja Frey in 1923, Frey's syndrome (FS), or auriculotemporal syndrome, is a rare condition characterised by gustatory sweating, typically encountered as sequelae following invasive head and neck surgery. The pathophysiology of FS can be described by aberrant reinnervation of postganglionic parasympathetic neurons to the surrounding denervated sweat glands and cutaneous blood vessels. Multiple invasive procedures have been associated with FS ranging from salivary gland surgery to burn reconstruction and thoracoscopic sympathectomies. Rarely, FS can be secondary to trauma or non-surgical aetiologies, including diabetes and infection. Physical symptoms vary based on the severity and surface area affected by FS and range from mild symptoms to severe psychosocial morbidity for patients. Surgeons operating in the head and neck, including otolaryngologists, maxillofacial surgeons, and plastic surgeons, should be aware of this potential complication and be up to date with diagnosis and treatment strategies for FS. This review article summarises the literature relating to FS focusing on its aetiologies, symptomatology, prevention, and available treatments, aiming to provide an up-to-date review of this condition for surgeons operating in the head and neck region. Although various treatment options have been suggested, these are often limited to topical agents that require life-long administration for symptom control. Further research is recommended to identify the optimal treatment for this condition and the role of surgery as a treatment for severe or refractory cases.

Infrahyoid myofascial flap transfer for the prevention of concave deformity and gustatory sweating after parotidectomy

OBJECTIVE

Concave deformities and gustatory sweating are the most common complications that cause substantial patient dissatisfaction after parotidectomy. Various surgical methods to prevent these complications have been described. However, effective techniques have not been established, especially in patients with medium- to large-sized parotidectomy defects. We evaluated the utility of infrahyoid myofascial flap reconstruction of parotidectomy defects for the prevention of these complications.

METHODS

We conducted a retrospective case series study in patients with a benign or malignant parotid tumor measuring over 4 cm who underwent immediate pedicle infrahyoid myofascial flap reconstruction after total or subtotal parotidectomy or total resection of either the superficial or deep parotid gland at our hospital. Subjective analyses of facial symmetry, postoperative concave deformities of the anterior neck, gustatory sweating, voice disorders, odynophagia, neck scarring in the parotid and anterior neck areas, sensory disorders, pain, and neck stiffness were performed using patient interview data. Objective evaluations of facial symmetry were made by the first or second author. Both analyses were performed after a follow-up of more than six months. Additionally, patient demographic data, clinicopathological factors, parotidectomy and skin incision types, flap survival, and postoperative complications were evaluated.

RESULTS

We included eight patients (male, n=5; mean age, 69.3 years [range, 37-93 years]). Procedures included total or subtotal parotidectomy (n=4), superficial lobe parotidectomy (n=2), and deep lobe parotidectomy with partial superficial lobe parotidectomy (n=2). Infrahyoid myofascial flaps reached the cranial tip of the parotid defect without tension, and their volume sufficiently filled the parotidectomy defect in all patients. There were no local signs of insufficient blood flow within the transferred flaps. OBJECTIVE AND SUBJECTIVE: assessments were made after a mean duration of 1.2 years (range, 0.6-1.8). Postoperatively, no patient subjectively reported facial asymmetry. Objectively, facial symmetry was "good" in four patients and "fair" in four patients. No distinctly visible concave deformity in the parotid or anterior neck area occurred in any patient. Gustatory sweating occurred in one patient; this individual had the largest parotidectomy defect. Only one patient experienced donor site morbidity (mild anterior neck stiffness) related to infrahyoid myofascial flap elevation.

CONCLUSION

Although complete prevention of gustatory sweating was unsuccessful, infrahyoid myofascial flap reconstruction of medium- to large-sized parotidectomy defects led to postoperative facial symmetry with minimal donor site morbidity.

Non-aesthetic uses of botulinum toxin in the head and neck

INTRODUCTION

The use of botulinum toxin in the specialty of aesthetic surgery in the head and neck is well known. However, it has also been used for other conditions affecting the head and neck, and in recent years its use, as well as the number of relevant applications, has expanded enormously.

REVIEW

This article presents a summary of the current range of uses in the laryngeal, pharyngeal, cervical, oromandibular and facial muscles and salivary glands. We highlight particular conditions focusing on dystonia (laryngeal, craniocervical, oromandibular and cervical), multiple system atrophy, migraines, facial nerve palsy, post-laryngectomy, cricopharyngeal dysphagia, Zenker's diverticulum, retrograde cricopharyngeal dysfunction disorder, sialorrhea and gustatory sweating (Frey's syndrome).

CONCLUSION

This article should aid the ear, nose and throat surgeon garner knowledge about the range of uses for botulinum toxin in the head and neck.

Management of parotid fistula and Frey's syndrome with Botulinum neurotoxin type A

The common cause of parotid fistula is parotid gland surgery and is frequently due to injury to the gland rather than to the duct. The frequency of postparotidectomy fistula is 14%. Other causes include facial trauma, congenital anomalies of the parotid gland, malignancies originating from the parotid gland and infections. Although there are several options for the treatment of parotid fistula and Frey's syndrome, very few treatment options are deemed optimal. The use of Botulinum A neurotoxin as a conservative method of treatment for parotid fistula and Frey's syndrome is a recent and evolving concept.

What is the best method for prevention of postparotidectomy Frey syndrome? Network meta-analysis

BACKGROUND

Prevention of Frey syndrome (FS) after parotidectomy using an interposition barrier has long been gaining a wide popularity; however, there is no clear evidence regarding which preventive technique is more effective. The aim of this network meta-analysis (NMA) is to answer the question: What is the best method for prevention of FS after parotidectomy?

METHODS

A comprehensive search of the PubMed, Embase, SCOPUS, and Cochrane library was conducted to identify the eligible studies. The outcome was the incidence of subjective Frey syndrome (SFS) and objective Frey syndrome (OFS). The Bayesian NMA accompanied with a random effects model and 95% credible intervals (CrIs) were calculated using GeMTC R package.

RESULTS

Thirty-four studies (n = 2987 patients) with five interventions, namely Alloderm (ADM), temporoparietal fascia (TPF), sternocleidomastoid muscle (SCM), superficial musculoaponeurotic system (SMAS), and free fat graft (FFG), were compared together and with no interposition barrier (NB). The results of NMA showed a statistically significant reduction in both SFS and OFS when ADM, TPF, SMAS, FFG, and SCM were compared with NB. No statistical differences were observed when comparing ADM, SCM, SMAS, FFG, and TPF. TPF ranked the best of all treatments (59.4%) and was associated with the least incidence of SFS; whereas ADM ranked the best of all treatments (61.1%) and was associated with the least incidence of OFS.

CONCLUSIONS

All interventions (TPF flap, ADM, FFG, SMAS, and SCM) were associated with a significant reduction in the incidence of FS when compared with NB. TPF and ADM showed the best outcome with the least incidence of SFS and OFS, respectively.

Use of Botulinum Toxin in Orofacial Clinical Practice

Introduction: Botulinum neurotoxin (BoNT) is a potent biological toxin and powerful therapeutic tool for a growing number of clinical orofacial applications. BoNT relaxes striated muscle by inhibiting acetylcholine’s release from presynaptic nerve terminals, blocking the neuromuscular junction. It also has an antinociceptive effect on sensory nerve endings, where BoNT and acetylcholine are transported axonally to the central nervous system. In dentistry, controlled clinical trials have demonstrated BoNT’s efficiency in pathologies such as bruxism, facial paralysis, temporomandibular joint (TMJ) disorders, neuropathic pain, sialorrhea, dystonia and more. Aim: This study’s aim was to conduct a systematic literature review to assess the most recent high-level clinical evidence for BoNT’s efficacy and for various protocols (the toxin used, dilution, dosage and infiltration sites) used in several orofacial pathologies. Materials and methods: We systematically searched the MedLine database for research papers published from 2014 to 2019 with randomly allocated studies on humans. The search included the following pathologies: bruxism, dislocation of the TMJ, orofacial dystonia, myofascial pain, salivary gland disease, orofacial spasm, facial paralysis, sialorrhea, Frey syndrome and trigeminal neuralgia. Results: We found 228 articles, of which only 20 met the inclusion criteria: bruxism (four articles), orofacial dystonia (two articles), myofascial pain (one article), salivary gland disease (one article), orofacial spasm (two articles), facial paralysis (three articles), sialorrhea (four articles) or trigeminal neuralgia (three articles). Discussion: The clinical trials assessed showed variations in the dosage, application sites and musculature treated. Thus, applying BoNT can reduce symptoms related to motor muscular activity in the studied pathologies efficiently enough to satisfy patients. We did not identify the onset of any important side effects in the literature reviewed. We conclude that treatment with BoNT seems a safe and effective treatment for the reviewed pathologies.

Botulinum Neurotoxins and Cancer-A Review of the Literature

Botulinum neurotoxins (BoNT) possess an analgesic effect through several mechanisms including an inhibition of acetylcholine release from the neuromuscular junction as well as an inhibition of specific pain transmitters and mediators. Animal studies have shown that a peripheral injection of BoNTs impairs the release of major pain transmitters such as substance P, calcitonin gene related peptide (CGRP) and glutamate from peripheral nerve endings as well as peripheral and central neurons (dorsal root ganglia and spinal cord). These effects lead to pain relief via the reduction of peripheral and central sensitization both of which reflect important mechanisms of pain chronicity. This review provides updated information about the effect of botulinum toxin injection on local pain caused by cancer, painful muscle spasms from a remote cancer, and pain at the site of cancer surgery and radiation. The data from the literature suggests that the local injection of BoNTs improves muscle spasms caused by cancerous mass lesions and alleviates the post-operative neuropathic pain at the site of surgery and radiation. It also helps repair the parotid damage (fistula, sialocele) caused by facial surgery and radiation and improves post-parotidectomy gustatory hyperhidrosis. The limited literature that suggests adding botulinum toxins to cell culture slows/halts the growth of certain cancer cells is also reviewed and discussed.

Graft interposition for preventing Frey's syndrome in patients undergoing parotidectomy

BACKGROUND

Frey's syndrome is characterised by transient flushing and sometimes facial sweating in the area of the auriculotemporal nerve. It most commonly occurs after parotidectomy, but other causes may include submandibular gland surgery, mandibular condylar fracture, obstetric (forceps) trauma, sympathectomy and metabolic disease. Although the pathophysiology of Frey's syndrome remains controversial, the generally accepted hypothesis is that it occurs as the result of injury to the auriculotemporal nerve.There is currently no clear evidence to establish the efficacy and safety of the different methods used for the treatment of Frey's syndrome, therefore the prevention of this symptom during surgery is important. The main method used for prevention is the interposition of a graft between the skin flap and the parotid bed during surgery. Biomaterials, allograft or autograft can be used for this purpose.

OBJECTIVES

To evaluate the effects and safety of biomaterial, allograft or autograft interposition for the prevention of Frey's syndrome in patients undergoing parotidectomy, and to identify its effect on prevention and delayed occurrence.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Trials Register; Cochrane Register of Controlled Trials (CENTRAL; 2019, Issue 2); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 5 February 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in patients with parotid disease (including tumours, inflammation, trauma etc.) undergoing parotidectomy with a minimal follow-up period of six months. We planned to include trials with interventions including biomaterial, allograft or autograft interposition alone or in combination with other surgical techniques. We included trials that compared any graft interposition and no graft interposition, or different graft interpositions.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. Our primary outcome measures were incidence rate of Frey's syndrome assessed clinically (Minor's starch-iodine test) and other complications (postoperative infection, subjective painful or restricted cervical movement, scar spread, rejection of the graft, complications related to the donor site such as accessory nerve injury and haematoma). Our secondary outcome measures were incidence rate of Frey's syndrome assessed by participants (by questionnaire) and sweating area assessed by Minor's starch-iodine test. We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We included three RCTs (124 participants), two of which we assessed as at high risk of bias and one at unclear risk of bias. All studies were hospital-based and recruited participants undergoing superficial parotidectomy. Most participants were diagnosed with benign lesions of the parotid gland. Participants were followed up for more than six months. The studies evaluated the two comparisons shown below:Sternocleidomastoid muscle flap versus no flapTwo studies assessed this comparison. Both assessed the effects of the sternocleidomastoid muscle flap procedure on the incidence rate of Frey's syndrome assessed clinically but neither showed a significant difference between groups (risk ratio (RR) 0.08, 95% confidence interval (CI) 0.00 to 1.23; 24 participants and RR 1.23, 95% CI 0.88 to 1.73; 36 participants; very low-certainty evidence). We did not pool the data due to the high heterogeneity (I² = 87%).One study found that the sternocleidomastoid muscle flap may result in little or no difference in other complications including haematoma (RR 2.18, 95% CI 0.09 to 50.16; 36 participants; low-certainty evidence), subjective painful or restricted cervical movement (RR 0.54, 95% CI 0.14 to 2.05; 36 participants; low-certainty evidence) and scar spread in the cervical region (RR 0.71, 95% CI 0.05 to 10.54; 36 participants; low-certainty evidence). Both studies reported the incidence rate of Frey's syndrome assessed by participants, with one reporting no events in either group and the other finding no evidence of a difference (RR 0.63, 95% CI 0.32 to 1.26; 36 participants; low-certainty evidence).Acellular dermal matrix versus no graftOnly one study assessed this comparison. Use of an acellular dermal matrix graft may result in little or no difference to the incidence rate of Frey's syndrome (assessed clinically) in comparison with the no graft group, but the evidence is very uncertain (RR 0.08, 95% CI 0.00 to 1.25; 30 participants; very low-certainty evidence).Acellular dermal matrix may slightly increase the wound infection rate compared with control (RR 17.00, 95% CI 1.02 to 282.67; 64 participants; low-certainty evidence). Acellular dermal matrix may result in little or no difference to the incidence of seromas or sialoceles (RR 2.33, 95% CI 0.66 to 8.23; 64 participants; low-certainty evidence). Acellular dermal matrix may result in little or no difference to the incidence rate of Frey's syndrome (assessed by participants) in comparison with the no graft group (RR 0.33, 95% CI 0.04 to 3.04; 64 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence for the effectiveness of graft interposition in preventing Frey's syndrome is of low or very low certainty. The use of acellular dermal matrix may be associated with an increase in the wound infection rate, and little or no difference in the incidence of seromas or sialoceles. Further studies are needed to draw reliable conclusions.

Botulinum toxin type A interrupts autophagic flux of submandibular gland

Botulinum toxin type A (BTXA) is a neurotoxic protein produced by Clostridium botulinum. Our previous studies demonstrated that BTXA inhibits the secretory function of submandibular gland (SMG) and changes its structure. Several studies reported that SMG damage and repair often occur with autophagy in the rat. However, no studies reported whether secretory inhibition and structural changes of SMG after BTXA injection is related with autophagy. The present study was carried out to explore the association between BTXA injection and autophagy in rat SMG. Western blotting and immunofluorescence were used to detect the expression and distribution of light chain 3 (LC3) in rat SMG. MTS was used to detect the toxicity of BTXA on rat SMG-C6 cell line. GFP-LC3 and Lyso-Tracker Red fluorescence probe were used to assess the levels of autophagosomes and lysosome fusion and the effect of BTXA on autophagic flux in SMG-C6. Western blotting and immunofluorescence results showed that BTXA temporarily increased autophagosomes in rat SMG. MTS results showed that BTXA exerted its toxicity on SMG-C6 in a dose-dependent manner. BTXA increased the number of autophagosomes in SMG-C6; however, most autophagosomes did not colocalize with lysosome. Therefore, we presume that BTXA can change autophagic flux of SMG cells, the mechanism of which might relate with BTXA’s disturbing autophagosome-lysosome fusion.

Use of botulinum toxin in Frey's syndrome

Frey's syndrome is the most common adverse event after parotidectomy, and usually, it appears after 6 months. In our case, symptoms appear 20 years from surgery, an uncommon condition. Intralesional botulinum toxin gives excellent results in therapy, regardless of the time elapsed between surgery and the first treatment.

The whole truth about botulinum toxin - a review

Treatment with botulinum toxin is widely viewed as safe, effective and largely devoid of serious side effects. There are two classes of Botox-related adverse events – transient and benign events, and potentially serious events. The aim of this study was to provide an overview of Botox-related side effects and advise potential management and preventive strategies. Benign side effects are well-localized, reversible and self-limited complications which develop within a few days of the injection, and they usually disappear without any treatment. The aesthetic and functional adverse effects are associated with different muscle responses to botulinum toxin or with misplacement of botulinum toxin. The serious events are sequelae due to the systemic spread of toxin leading to botulism.

Temporoparietal frey syndrome: An uncommon variant of a common syndrome

OBJECTIVES/HYPOTHESIS

To describe a previously unreported variant of Frey syndrome. Gustatory sweating is a common complication of parotidectomy and typically directly overlies the surgical site or parotid bed. In some instances, the sweating may occur beyond the parotid bed or involve tissue that was undisturbed during the procedure.

STUDY DESIGN

Retrospective case series.

METHODS

All cases of temporoparietal Frey syndrome in a single surgeon's experience were reviewed.

RESULTS

Seven patients were found to have temporoparietal Frey syndrome. Three patients had concomitant first bite syndrome. Three patients had some form of reconstruction at time of surgery. The mean time to onset of symptoms was 11.5 months, with a range of 7 to 21 months. Four patients did not require any treatment for their symptoms, but two patients required intradermal Botox injections for symptomatic relief.

DISCUSSION

This study describes a previously unreported variant of Frey syndrome with symptoms occurring distal to the parotid gland. This likely develops either by regeneration of severed postganglionic fibers into sympathetic targets distally along the course of the auriculotemporal nerve or by regeneration into fibers of the sympathetic plexus traveling along the superficial temporal artery.

LEVEL OF EVIDENCE

Laryngoscope, 129:2071-2075, 2019.

Botulinum toxin therapy: functional silencing of salivary disorders

Botulinum toxin (BTX) is a neurotoxic protein produced by Clostridium botulinum, an anaerobic bacterium. BTX therapy is a safe and effective treatment when used for functional silencing of the salivary glands in disorders such as sialoceles and salivary fistulae that may have a post-traumatic or post-operative origin. BTX injections can be considered in sialoceles and salivary fistulae after the failure of or together with conservative treatments (e.g. antibiotics, pressure dressings, or serial aspirations). BTX treatment has a promising role in chronic sialadenitis. BTX therapy is highly successful in the treatment of gustatory sweating (Frey's syndrome), and could be considered the gold standard treatment for this neurological disorder.

Mupirocin in the Treatment of Staphylococcal Infections in Chronic Rhinosinusitis: A Meta-Analysis

Background

Saline irrigation of the nasal cavity is a classic and effective treatment for acute or chronic rhinosinusitis. Topical antibiotics such as mupirocin have been widely used for recalcitrant chronic rhinosinusitis. Therefore, the purpose of this study was to evaluate the effect of saline irrigation using mupirocin.

Methods

A systematic literature review and meta-analysis of mupirocin saline irrigation were performed using EMBASE, MEDLINE, and Cochrane library through December 2015. Data were analyzed with R 3.2.2 software. A random effects model was used because of the diversity of included studies. Sensitivity analysis of particular tested groups and single proportion tests were also performed. The main outcome measure was residual staphylococcal infection, as confirmed by culture or PCR.

Results

Two RCTs, two prospective studies and two retrospective studies were included. A random effects model meta-analysis of the pooled data identified a relative risk of residual infection of 0.13 (95% CI: 0.06–0.26, p<0.05) with low heterogeneity (I² = 0%). The proportion of residual staphylococcal infections after 1 month was 0.08 (95% CI: 0.04–0.16). However, this proportion increased to 0.53 at 6 months (95% CI: 0.27–0.78).

Conclusions

The short-term use of mupirocin has a strongly reductive effect on staphylococcal infection in chronic rhinosinusitis. Although there is currently a lack of clear evidence, future studies with well-designed inclusion criteria and randomized controlled trials are needed to examine mupirocin’s long-term effect on chronic rhinosinusitis.

An Experimental Study on Botulinum Toxin Type A for the Treatment of Excessive Secretion after Submandibular Gland Transplantation in Rabbits

Objectives. To investigate whether botulinum toxin type A (BTXA) could control excessive secretion after submandibular gland (SMG) transplantation in rabbits and its possible mechanisms. Methods. A new SMG transplantation model was established in rabbit. 30 successfully constructed models were randomly assigned to five groups including control group and four experimental groups. Secretion outputs were used to analyze the effect of BTXA injection on excessive secretion. Hematoxylin and eosin (HE) staining, transmission electron microscopy (TEM), Western blot, and immunofluorescence were performed to analyze its possible mechanisms. Results. After BTXA injection, a significant decrease of excessive secretion after SMG transplantation was found in 2 and 4 weeks groups, but no significant effect on 12 and 24 weeks groups. HE and TEM results showed that BTXA led to morphological and ultrastructural changes of acinar cells of transplanted SMG. Western blot results suggested that BTXA decreased the aquaporin-5 (AQP5) protein expression after BTXA injection for 2 and 4 weeks. Immunofluorescence results showed that AQP5 protein was mainly expressed in the cytoplasm after BTXA injection for 2 and 4 weeks, which might indicate that BTXA promoted AQP5 expression from the cell membrane to cytoplasm. Conclusion. BTXA could effectively control excessive secretion after SMG transplantation in rabbits.

What is the Prognostic Significance of Ki-67 Positivity in Oral Squamous Cell Carcinoma?

BACKGROUD

Numerous studies have stated that Ki-67 is a good prognostic marker in oral squamous cell carcinoma (OSCC). However, some researchers believe the contrary. To address this controversy, we performed a systematic literature retrieval to estimate the prognostic significance of Ki-67 expression in patients with OSCC.

METHODS

Databases covering Pubmed, Ovid, Web of Science, Embase and the Cochrane library were searched regardless of publication year. Overall survival (OS), local recurrence (LR) and disease-free survival (DFS) were the main outcome measures. Relative risks (RRs) and its 95% confidential intervals (CIs) were used for statistical analysis.

RESULTS

Twenty-seven articles with 2146 patients were included in this study. The results of the meta-analysis suggested that the pooled RRs and its CIs for OS, LR, and DFS were 1.45 (1.15 - 1.84), 1.76 (0.74 - 4.16) and 1.52 (1.07 - 2.14), respectively. However, the heterogeneities of OS and LR were obvious (I-squared (OS) = 59.4%, I-squared (LR) = 72.6%). After subgroup analysis based on systemic treatment, the cut-off value of Ki-67 expression, ethnicity and types of antibody, the heterogeneities became acceptable. It was observed that systemic treatment, cut-off values of Ki-67 expression, ethnicity and the types of antibody affected the results. The statistical analyses of subgroups suggested that non-systemic treatment, (OR=1.77, 95% CI = 1.39-2.25, p = 0.000) and Asian populations (OR=2.09, 95% CI = 1.32-3.32, p = 0.002) are high risks for Ki-67 high expression, and low cut-off value of Ki-67 expression (OR = 1.44, 95% CI = 1.001-2.072), MIB-1 antibody (OR = 1.48, OR 95% = 1.10-1.99) might affect the identification of results.

CONCLUSIONS

According to this meta-analysis, high Ki-67 expression might be a negative prognostic marker of patients with OSCC, especially in Asian populations. In addition, Ki-67 expression affects the treatment response.