Management of Frey syndrome

Effects of acellular dermal matrix on the prevention of complications and esthetic outcome after parotidectomy: A propensity score matched analysis

OBJECTIVE

The present study was designed to investigate whether acellular dermal matrix (ADM) grafts could prevent Frey's syndrome (FS) and improve esthetic scores following parotidectomy.

METHODS

From January 2015 to December 2019, 175 patients underwent parotidectomy. We divided the patients into two groups: the ADM group and the control group. We included in each group 30 patients according to a propensity score matched analysis.

RESULTS

FS was subjective in 1 patient (3%) from the ADM group and 9 patients (30%) from the control group (P=0.015). Patients in the ADM group had a subjective esthetic score of 6.1 + 1.7 compared with 5.2 + 1.7 in the control group. The subjective esthetic score for patients in the ADM group was higher than that for patients in the control group (P =0.040).

CONCLUSION

The present clinical study suggests that ADM grafts are effective in preventing FS and improving esthetic scores after parotidectomy.

Factors influencing Frey syndrome after parotidectomy with acellular dermal matrix

BACKGROUND

Frey syndrome, also known as ototemporal nerve syndrome or gustatory sweating syndrome, is one of the most common complications of parotid gland surgery. This condition is characterized by abnormal sensations in the facial skin accompanied by episodes of flushing and sweating triggered by cognitive processes, visual stimuli, or eating.

AIM

To investigate the preventive effect of acellular dermal matrix (ADM) on Frey syndrome after parotid tumor resection and analyzed the effects of Frey syndrome across various surgical methods and other factors involved in parotid tumor resection.

METHODS

Retrospective data from 82 patients were analyzed to assess the correlation between sex, age, resection sample size, operation time, operation mode, ADM usage, and occurrence of postoperative Frey syndrome.

RESULTS

Among the 82 patients, the incidence of Frey syndrome was 56.1%. There were no significant differences in sex, age, or operation time between the two groups (P > 0.05). However, there was a significant difference between ADM implantation and occurrence of Frey syndrome (P < 0.05). ADM application could reduce the variation in the incidence of Frey syndrome across different operation modes.

CONCLUSION

ADM can effectively prevent Frey syndrome and delay its onset.

Late Prevalence of Typical and Atypical Symptoms of Frey's Syndrome after Parotidectomy for Benign Tumor

BACKGROUND

The treatment of choice for tumors located in the parotid gland is surgery. Nevertheless, postoperative complications are not infrequent. Regardless of the type of surgical procedure, the most common complication is Frey's syndrome (FS). Traditionally, FS includes unilateral gustatory sweating and flushing of the facial skin lining the parotid compartment. Recent research describes atypical discomfort associated with FS. The aim of this study was to assess the late prevalence and severity of both usual and atypical symptoms after parotidectomy for benign tumors.

METHODS

We conducted a cross-sectional study involving 86 subjects who underwent superficial parotidectomy at least one year before the study. The questionnaire included the sweating-flushing-itch-paresthesia-pain (SFIPP) Frey scale supplemented by specific questions about symptoms.

RESULTS

Sixty-seven out of eighty-six (77.9%) cases reported almost one symptom. The most frequent symptom was itch (36/67-53.7%), followed by pain (35/67-52.2%), while 28/67 (41.8%) subjects complained of atypical symptoms without flushing or sweating. A desire to treat the discomfort was reported by 50/67 (74.6%) subjects.

CONCLUSIONS

Late postparotidectomy local discomfort is not infrequent and includes both usual and "unusual" symptoms almost equally. Our results suggest the importance of informing patients about the occurrence of the syndrome and the available treatment options during pre- and postoperative counseling.

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.

Frey syndrome after conservative parotidectomy: Importance of closing the remnant parotid parenchyma

BACKGROUND

Frey syndrome (FS) is a typical late complication following parotidectomy. Parotid surgery without proper coverage or reconstruction of exposed parotid parenchyma may contribute to the development of FS. Therefore, this study compared the closure versus the non-closure of exposed parotid parenchyma in the occurrence of FS.

METHODS

This study included 195 patients with parotid lesions who underwent partial or superficial parotidectomy plus closure or non-closure of exposed parotid parenchyma, both with the application of fibrin glue. Two surgical methods of closure and non-closure were allocated to patients without randomization and blinding processes. The primary outcome was FS, and the second outcome was other complication rates.

RESULTS

The closure and non-closure of exposed parotid parenchyma were performed in 102 and 93 patients, respectively. Early postoperative complications occurred with temporary events: transient facial weakness, 32 (16.4%); hematoma, 13 (6.7%); and wound infection, 2 (1.0%), without statistical difference between the two groups (P > 0.1). However, sialocele occurred in the non-closure group (n = 19) more than in the closure group (n = 7) (P = 0.005). In the first postoperative year, decreased sensation and local pain were found in 16 patients (8.2%) and 9 patients (4.6%), respectively, with no statistical difference between the two groups (P > 0.1). FS was found more in the non-closure group (n = 19, 20.4%) than in the closure group (n = 4, 3.9%) (P < 0.001).

CONCLUSION

The closure of exposed parotid parenchyma and covering fascia is preferred over the non-closure to prevent FS.

Innsbruck-style Retromandibular Anterior Trans-parotid Approach for Condylar Fractures: A Retrospective Review of 39 Fractures

The retromandibular anterior trans-parotid (RAT) approach and a triangular-positioned double mini-plate osteosynthesis (TDO) technique have been reported from Innsbruck Medical University. This minimally invasive technique involves direct visualization of the condyle and is associated with lower incidence of facial palsy.

Methods

A retrospective review was performed on the RAT approach and TDO technique conducted by a surgeon and team at two hospitals in Tokyo during a period of 3 years and 10 months.

Results

This technique was performed on 35 patients with 39 condylar fractures. Sixty-nine percent of cases were due to accidental fall, 17% to traffic accidents, and 9% to sports. Furthermore, 92% cases were condylar base fractures. Nighty-seven percent of cases achieved good occlusion. The mean maximum mouth opening was 49 ± 1.3 mm. Postoperatively, facial palsy developed in three patients (7.7%), and two of them developed Frey syndrome at approximately 2.5 years postoperatively (5.1%). All patients completely recovered within 3 months postoperatively. One case each of salivary fistula, visible scar, and condylar resorption was found (2.6%). No case of massive bleeding during surgery, hematoma, or TMJ pain after surgery was found.

Conclusion

This technique could achieve good occlusion with low incidence of complications and could contribute to early social reintegration among patients.

Brief Clinical Study: An Alternative Method to Prevent Frey Syndrome After Resection of Huge Masses in Parotis: De-epithelialized Skin Flap Use

Frey syndrome is still a significant problem in postparotidectomy patients 6 to 18 months after surgery. The most accepted theory of the pathogenesis of Frey syndrome is the aberrant regeneration theory. Creating a barrier between the remnant parotid gland and the overlying skin prevents Frey syndrome. A 51-year-old female patient who developed pleomorphic adenoma in the parotid gland was operated. After superficial parotidectomy, a barrier between the underlying postganglionic parasympathetic nerves in the deep parotid gland and the overlying cutaneous tissue was created with a local skin flap to prevent Frey syndrome. The patient was successfully treated, and she was followed up to 5 years. No postoperative complications were observed. No signs of Frey syndrome were found in follow-up. This case highlights that local skin flaps can be an innovative natural method as it is a quick and simple method to create this barrier in the presence of expanded skin.

Lipofilling after total parotidectomy: a useful option to prevent functional and aesthetic sequelae

Objective

Parotidectomy is the main treatment for parotid tumours, but its functional and aesthetic sequelae can be very disturbing for patients.

Methods

15 patients underwent total conservative parotidectomy, harvesting of a superficial musculoaponeurotic system (SMAS) flap and lipofilling between May 2014 and June 2020 for a benign parotid tumour. Aesthetic, functional sequelae and cosmetic results were assessed with the House-Brackmann scale, Luna-Ortiz's classification and a semiquantitative questionnaire. Lipofilling resorption was analysed by maxillofacial and neck MRI imaging at 2 years after surgery. The results were compared to a group of 21 patients who underwent total parotidectomy without harvesting a SMAS flap and lipofilling.

Results

No complications were observed. No facial defects were seen during follow-up. Post-operative MRI showed fat resorption was less than 20% in 12 patients and from 20 to 30% in 3 patients. Cosmetic satisfaction was 100% in all cases. Only 1 patient (6%) complained of Frey's syndrome.

Conclusions

Lipofilling is an excellent solution considering its efficacy, safety, simplicity, duration over time and economic costs. Donor site invasiveness is minimal, and reintervention is always possible. Face-lift incision and SMAS flap can improve aesthetic results and minimise the disfiguring impact of the surgical scar.

Identification of cranial nerve ganglia using sectioned images and three-dimensional models of a cadaver

Background

Cranial nerve ganglia, which are prone to viral infections and tumors, are located deep in the head, so their detailed anatomy is difficult to understand using conventional cadaver dissection. For locating the small ganglia in medical images, their sectional anatomy should be learned by medical students and doctors. The purpose of this study is to elucidate cranial ganglia anatomy using sectioned images and three-dimensional (3D) models of a cadaver.

Methods

One thousand two hundred and forty-six sectioned images of a male cadaver were examined to identify the cranial nerve ganglia. Using the real color sectioned images, real color volume model having a voxel size of 0.4 × 0.4 × 0.4 mm was produced.

Results

The sectioned images and 3D models can be downloaded for free from a webpage, anatomy.dongguk.ac.kr/ganglia. On the images and model, all the cranial nerve ganglia and their whole course were identified. In case of the facial nerve, the geniculate, pterygopalatine, and submandibular ganglia were clearly identified. In case of the glossopharyngeal nerve, the superior, inferior, and otic ganglia were found. Thanks to the high resolution and real color of the sectioned images and volume models, detailed observation of the ganglia was possible. Since the volume models can be cut both in orthogonal planes and oblique planes, advanced sectional anatomy of the ganglia can be explained concretely.

Conclusions

The sectioned images and 3D models will be helpful resources for understanding cranial nerve ganglia anatomy, for performing related surgical procedures.

Effectiveness of the Fibrinogen-Thrombin-Impregnated Collagen Patch in the Prevention of Postoperative Complications after Parotidectomy: A Single-Blinded, Randomized Controlled Study

We investigated whether a fibrinogen-thrombin collagen sponge patch reduces postoperative complications of parotid gland surgery. This single-blinded, randomized controlled study included 165 patients who underwent parotid surgery for benign tumors (2018–2019) at a tertiary center. Primary outcomes were postoperative drain amount, days until drain removal, and discharge. Patients were scheduled for follow-up at 1 and 4 weeks, and 3 months after surgery. Complications including surgical site infection, pain, seroma, sialocele, salivary fistula, facial nerve palsy, Frey’s syndrome with subjective symptoms, and facial asymmetry were analyzed. After identifying confounding variables, multivariate approaches were used. Histologic analysis was performed in a mouse model of salivary gland surgery. In total, 162 patients (77, fibrinogen-thrombin collagen patch group; 85, controls) were included, with no significant between-group differences other than resected tissue. Among postoperative total drain amount and days until drain removal and discharge, the only postoperative total drain was significantly lower in the patch group than in the control group in the adjusted model. Additionally, although validation through robust trials with longer follow-up is needed, we found the potential benefit of the fibrinogen patch on Frey’s syndrome and facial asymmetry. In conclusion, fibrinogen-thrombin-impregnated collagen patches in parotidectomy can reduce postoperative drainage and improve outcomes.

Frey's syndrome: A review of the physiology and possible role of neurotrophic factors

OBJECTIVES

Frey's syndrome (FS) describes the phenomenon of gustatory sweating and is a cause of significant social embarrassment for sufferers. It has been attributed to aberrant growth of parasympathetic salivatory fibers in the auriculotemporal nerve toward overlying sweat glands. However, the exact mechanism behind this growth is unknown. This review aims to expand and elucidate the theory of aberrant regeneration in FS.

METHODS

A review of the recent literature on nerve regeneration was conducted in order develop further insights into the etiology of both adult onset and pediatric FS.

RESULTS

Neurturin, a neurotrophic factor released by both salivary and sweat glands, was identified as a possible key player in the etiology of FS.

CONCLUSION

Further research into the role of neurturin could help to elucidate the pathogenic mechanisms underlying the condition and might reveal neurturin to be a potential target for pharmacological intervention.

LEVEL OF EVIDENCE

NA (Basic Science Review).

The effects of residual parotid volume on symptom-specific quality of life and complications in patients undergoing parotid surgery

PURPOSE

To measure postoperative residual parotid volumes in parotidectomy patients and to measure the effect of residual parotid volumes on the symptom-specific quality of life (SSQOL) and complications.

METHODS

Between January 2010 and December 2016, 148 parotid gland surgeries were performed, and 74 patients were included in the study. Bilateral parotid gland volumes were measured by Magnetic Resonance Imaging (MRI). Parotidectomy Outcome Inventory-8 and aesthetic scale questionnaire were applied to the patients. The volumetric averages obtained were compared with the questions in the SSQOL scale, the aesthetic scale data, and complications.

RESULTS

In the volumetric examination performed with MRI, the mean residual volumes of the operated parotid glands were 9.5 cm³, while the non-operated side was 28.8 cm³. The width of the surgery and the residual parotid tissue volume was inversely correlated. There was a statistically significant difference between the residual parotid gland volume and the pain related to the surgical area, depression in the surgical site, Frey's syndrome, incision scar, and numbness. As the residual parotid gland volumes decreased, the patients' cosmetic problems related to the surgical field increased significantly, and their SSQOL decreased.

CONCLUSION

Postoperative residual parotid tissue volume could be an objective parameter to measure patients' SSQOL and complications. After parotidectomy, the maximum amount of disease-free tissue of the parotid gland should be left in place to increase patients' quality of life and minimize complications.

Autologous Free Dermal-Fat-Fascial Graft for Parotidectomy Defects: A Case Series

Background:

Frey’s syndrome and facial asymmetry from loss of parotid tissue are long-term sequelae of parotid surgeries causing significant morbidity. Various techniques have been used to fill the parotidectomy defect, preserve facial contour symmetry, and prevent Frey’s syndrome. Free dermal-fat-fascial graft (DFFG) is one such technique; however, its use is largely undocumented in the literature. In this case series, we investigate the efficacy of free DFFG in reconstructing parotidectomy defects at 2 tertiary care centers.

Materials and methods:

Medical records of 54 patients who underwent primary parotidectomy and immediate reconstruction with autologous abdominal free DFFG by 2 surgeons in George Washington University Hospital and McGill University Health Centre between 2007 and 2019 were collected prospectively. Patients responded to 2 questionnaires addressing postoperative outcomes.

Results:

Fifty-four patients were included; 32 superficial parotidectomies and 22 total parotidectomies were performed for 39 benign and 15 malignant tumors. Thirty-seven patients could be reached. Out of 37 patients who responded to the first questionnaire, 59% (22) reported complete facial symmetry, 27% (10) reported mild hollowness, and 14% (5) reported mild fullness. None declared noticeable hollowness or fullness. While 81% (30) did not experience Frey’s syndrome, 5.4% (2) experienced mild symptoms without disability, and 13.5% (5) experienced debilitating symptoms. Out of 37 patients, 8 patients responded to a second questionnaire addressing the outcome of the abdominal graft donor site. In regard to the donor site, 87.5% (7) were satisfied or very satisfied from its cosmetic appearance, 75% (6) were not bothered by its cosmetic appearance, and 87.5% (7) had no discomfort at the graft donor site. Patients did not report any other symptom at the graft donor site.

Conclusion:

In this large series of total parotidectomies including malignant pathologies, autologous abdominal free DFFG effectively prevented Frey’s syndrome and preserved facial cosmesis in most patients.

Prevention of Frey's Syndrome with the Use of Porcine Dermal Collagen Graft: Retrospective Analysis of 76 "Formal" Parotidectomies for Benign Pathologies

BACKGROUND

Frey's syndrome is a well-known complication of parotid surgery; its prevention may be achieved by the use of an interpositional barrier between the overlying flaps and the exposed parenchymal bed of parotid gland. The aim of this study was to retrospectively evaluate clinical outcomes with and without the interpositional placement of a porcine dermal collagen graft (PDCG) for prevention of syndrome occurrence.

METHODS

We conducted a 20-year retrospective study including the patients who had undergone "formal" (superficial, total, or subtotal) parotidectomies for benign pathologies. The inclusion criteria also involved patients that were (i) regularly monitored about clinical symptoms related to syndrome, and (ii) examined with Minor starch-iodine test. The severity of the diagnosed syndrome was retrospectively evaluated according to the grading score system of Luna-Ortiz. To assess group differences in terms of the extent of dissection in operating sites, we estimated the tumor and histological specimen volumes using the available dimensions.

RESULTS

We included 73 patients who had undergone 76 formal parotid surgeries. The surgical sites were divided into 2 groups: (1) Group A consisted of 44 sites that were reconstructed with a SMAS flap, and (2) Group B, comprised 32 sites where a PDCG was additionally applied as an artificial preventive barrier. At a mean follow-up of 26.3 months, a significantly lower incidence of clinically diagnosed Frey's syndrome was found after the use of dermal collagen interpositional barrier (P = .031). Specifically, subjective symptoms were reported at an incidence of 31.8% in Group A and 6.7% in Group B. Minor's test was positive at an incidence of 59.09% in Group A and 21.87% in Group B (P = .004, 95% CI). Severe Frey's syndrome was observed in 31.82% of the patients of Group A and in 3.12% of the patients of Group B (P = .002, 95% CI). Since there were no statistical significant differences between the volumes of the removed tumors and the excised histological specimens, the extent of dissection was not proved to influence the occurrence of Frey's syndrome in the compared groups.

CONCLUSION

Porcine dermal collagen is a safe, practical, and useful means for parotid reconstruction, since it seems to contribute in prevention of Frey's syndrome when increased amount of glandular tissue has to be removed. Additional randomized controlled studies with bigger samples are required to better assess the PDCG use in parotid surgery.

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.

Intra-auricular modification of facelift incision decreased the risk of Frey syndrome

Objective

Frey syndrome is a complication followed by parotidectomy which caused gustatory sweating and facial flush. There were several methods for the prevention of Frey syndrome, but most of them had no obvious effects. In this study, we compare the intra-auricular modification of facelift incision with the traditional lazy-S incision to see if it can decrease the risk of Frey syndrome.

Materials and Methods

This is a retrospective study. From 2003 to 2009, a total of 61 patients with benign parotid tumor who received parotidectomy at Hualien Tzu Chi Hospital and were followed at outpatient department for at least 5 years were enrolled. Patients were divided into two groups according to the type of incisions during operation: (1) Group M: intra-auricular modification of facelift incision or (2) Group S: traditional lazy-S incision. All patients received the partial thickness sternocleidomastoid muscle flap. Clinical data including age, gender, pathologic result, presentation of Frey syndrome, size of tumor, length of operation, blood loss from surgery, length of placement of drain, total amount of drainage, and length of stay were collected and analyzed.

Results

Sixty-one patients were enrolled. Eighteen patients were in Group M and forty-three were in Group S. There was no significant difference of age, gender, and size of tumor between the two groups. The pathologic results included parotitis, pleomorphic adenoma, Warthin's tumor, and others. No significant difference of pathologic results, blood loss from surgery, length of placement of drain, total amount of drainage, and length of stay between two groups was obtained. The length of operation was longer in Group M (P = 0.001) and the incidence of Frey syndrome was lower in Group M than Group S (P < 0.05).

Conclusions

The use of intra-auricular modification of facelift incision can decrease the incidence of Frey syndrome.

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.

Superficial parotidectomy versus extracapsular dissection: literature review and search for a gold standard technique

Benign parotid tumours usually present as a slow-growing, asymptomatic mass in the pre-auricular region. Although they are uncommon, surgical excision is the mainstay of treatment due to the risk of malignant transformation in some benign tumours. Surgical techniques have evolved over the years, with superficial parotidectomy and extracapsular dissection being the current procedures of choice. There is currently no gold standard, and it remains unclear which surgical modality is the superior option. A literature review was performed in relation to the relative merits of each technique and to evaluate the reasons underpinning the ongoing debate. A total of 16 papers comparing the main clinical outcomes of the procedures were critically reviewed using the PRISMA protocol. Overall, extracapsular dissection indicated a reduced recurrence rate, facial nerve paralysis, Frey syndrome, and operation time. The superior outcomes following extracapsular dissection could be attributed to the less radical nature of the procedure. However, there were various limitations identified within the review that may have affected the results. Selection bias was the most significant, with patients assigned to the different procedures depending on the tumour size and location. Consequently, the debate continues as to what constitutes the gold standard of care for benign parotid tumours.

Acellular dermal matrix (Insuregraf) in the prevention of Frey's syndrome and surgical site depression after parotidectomy

BACKGROUND

Parotidectomy is the treatment of choice in many parotid tumors. Due to the extensive nature of the procedure, unfavorable complications such as gustatory sweating, surgical site depression are common. Various techniques using fascia, muscle or AlloDerm have been developed but debate still remains regarding its availability and affordability. We applied a newly developed acellular dermal matrix (Insuregraf) to the parotidectomy field to act as a physical barrier and to provide adequate filling effect for prevention of functional and aesthetic complications.

METHODS

From March 2010 to March 2017, 30 patients with parotid tumors underwent superficial parotidectomy. Twenty patients underwent only superficial parotidectomy. Ten patients had Insuregraf applied to the surgical site after superficial parotidectomy. We evaluated the incidence of Frey's syndrome, surgical site depression, and patient satisfaction rate in both groups.

RESULTS

The incidence of Frey's syndrome was lower in the Insuregraf group (0 vs. 2). Surgical site depression was also lower in the Insuregraf group (2 vs. 20). Satisfaction score for facial contour in Insuregraf group was 9.2 out of 10, which was comparable to 6.2 out of 10 in the control group.

CONCLUSION

Application of Insuregraf after superficial parotidectomy is an effective surgical procedure to prevent complications such as Frey's syndrome and surgical site depression. This technique is affordable and safe with no immune reactions. Above all this surgical method should be considered as an option for patients who are concerned about the contour of the face after surgery.

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.

Frey syndrome following herpes zoster in an otherwise healthy girl

A 12-year-old girl presented with red spots appearing on the left side of her face. The girl was usually healthy and fully vaccinated, including varicella vaccination.Six years prior to her presentation, she had suffered an episode of blister rash on the left side of her face, including lesions in the ear canal and buccal mucous membrane. A diagnosis of herpes zoster was made, and she was treated with acyclovir with complete skin recovery. A hearing examination demonstrated mild-to-moderate left neurosensory hearing loss.Since then, she is having short episodes of redness on her face without pain or sweating at the exact distribution of the zoster blisters 6 years ago. The appearance of spots is related to sour foods, such as sour flavoured candies, yoghourt and green apples. The diagnosis of postherpetic Frey syndrome was made, and observational approach was adopted due to the benign character of symptoms.

Use of the SMAS flap for reconstruction of the parotid lodge

The purpose of our study was to evaluate the benefits of the SMAS flap in patients with benign tumours of the parotid gland treated by superficial parotidectomy. We carried out a retrospective chart review on 123 patients suffering from benign tumours of the parotid gland admitted to our Institution between March 1997 and March 2010. A superficial parotidectomy was performed in all the cases reported. Our sample was divided in two groups basing SMAS flap reconstruction done (Group 2) or not (Group 1) after superficial parotidectomy. Reconstruction using SMAS flap was accomplished in 64 patients. Chi-square test was used to assess statistical difference between the two groups. The level of statistical significance was P < 0.05. No significant differences concerning hematoma, wound infection and facial paralysis were observed between the first and second group (3.38 vs 1.56% [P > 0.05], 8.47% vs 4.68% [P > 0.05], 5.08% vs 0.00% [P > 0.05]). Transient facial nerve weakness, fistula, dip skin and Frey's syndrome were significantly more frequent without SMAS flap reconstruction (10.16% vs 3.125% [P < 0.05], 13.55% vs 3.125% [P < 0.05], 13.55% vs 3.125% [P < 0.05], 20.33% vs 0% [P < 0.05] respectively). The use of the SMAS flap is able to reduce the cosmetic and functional complications that occur after the removal of a benign tumour of the parotid through the superficial parotidectomy technique, above all, it reduces the occurrence of Frey's syndrome.

The Effects of Superficial Musculoaponeurotic System Flap on the Development of Frey's Syndrome and Cosmetic Outcomes After Superficial Parotidectomy

Objective

To investigate the outcomes of superficial musculoaponeurotic system (SMAS) flap and classic techniques in superficial parotidectomy in terms of Frey's syndrome (FS) and cosmetic satisfaction.

Methods

In this study, a retrospective chart review of patients that underwent superficial parotidectomy was performed. These patients were divided into two subgroups: group 1 included patients in which the SMAS flap was harvested and group 2 comprised the remaining patients on whom classic superficial parotidectomy was performed. All the patients were evaluated clinically and with Minor's starch-iodine test for FS. For the evaluation of the cosmetic results, the patient's satisfaction was queried according to the incision scar and surgical field skin retraction/facial symmetry. Both groups were compared in terms of complications and numbness of surgical area.

Results

Fifty-five patients (31 male and 24 female) with a mean age of 50.19 years were included in the study. Thirty-two patients were in group 1 and 23 in group 2. Thirteen patients (23.7%) described as having FS and six of them were in group 1, while seven were in group 2. Minor's starch-iodine test was positive in nine patients in group 1 (28.1%) and six patients in group 2 (26.1%) (p=1.000). With regard to cosmetic satisfaction, eight patients (25%) stated mild discomfort from the incision scar and two patients (6.3%) stated cosmetic dissatisfaction for facial asymmetry in group 1. In group 2 for the same factors the number of patients were 11 (47.8%) and 2 two (8.7%), respectively (p=0.027). There were no statistically significant differences in means of complication and numbness (p>0.05).

Conclusion

According to our study results, there was no superiority between both the groups in terms of FS and incision scar satisfaction. We determined that there was a significant benefit of SMAS flap application in the prevention of volume loss and surgical area retraction.

Effectiveness of platysma muscle flap in preventing Frey syndrome and depressive deformities after parotidectomy

BACKGROUND

Frey syndrome (FS) or depressive deformity (DD) occurring after parotidectomy significantly reduces a patient's quality of life. However, there seems to be no effective treatment strategy against these complications. In this study, we report our experience of using platysma muscle flap (PMF) to prevent the development of FS and DD after parotidectomy, and evaluate its effect subjectively and objectively.

METHODS

Superficial parotidectomy was performed for eight cases of parotid gland tumor, and a PMF was transferred to cover the site. The incidence of FS and DD were evaluated subjectively, using a questionnaire to the patients and board-certified reconstructive surgeons, and objectively, using Minor's starch-iodine test.

RESULTS

In seven patients, the defect could be completely covered with PMF, and none of them developed FS or obvious DD. However, in one patient, the defect could be only partially covered, and the patient developed complications in the exact site that the flap did not cover. Overall scores from the questionnaire were high in relation to both cosmetic and functional perspectives from most of the patients and all the surgeons. No patients had major postoperative complications requiring revision.

CONCLUSIONS

PMF can be useful to cover the defect and prevent complications after parotidectomy. PMF is relatively easy to perform with fewer complications; however, a complete coverage of the defect should be ensured to obtain optimal results.

Frey's Syndrome After Herpes Zoster Virus Infection in a 2-Year-Old Girl

Frey's syndrome is characterized by sweating and flushing in the temporal and preauricular areas after a salivary stimulus. It is caused by damage to the auriculotemporal nerve, hence the alternative name of auriculotemporal syndrome. We report the case of a 2-year-old girl presenting with postprandial unilateral flushing that developed after a herpes zoster infection.

[Radiation therapy for pleomorphic adenoma of the parotid]

Parotid pleomorphic adenoma is the most frequent tumor of salivary glands. The prognosis depends on the recurrences because they could lead to iatrogenic events (facial paralysis). Moreover the risk of malignant transformation increases with the number of local relapses. This article aims at reviewing histological and radiological criteria and the surgical techniques. To improve local control, adjuvant irradiation (in first intention or after recurrence) may be useful but is still controversial for benign tumors in young patients with a risk of radio-induced cancer. We listed studies in which adjuvant radiotherapy was used so as to define its place in the treatment strategy. Prognostic factors were found by some authors. Other studies have to be done before strong evidence-based recommendations are issued.

Comparisons of Three Indicators for Frey's Syndrome: Subjective Symptoms, Minor's Starch Iodine Test, and Infrared Thermography

OBJECTIVES

To correlate Frey's syndrome with subjective symptoms, Minor's starch iodine test results, and infrared thermography measurements, and to discuss the utility of thermography as a quantitative diagnostic method.

METHODS

This study included 59 patients who underwent unilateral parotidectomy. A subjective clinical questionnaire and an objective Minor's starch iodine test were performed to evaluate the incidence of Frey's syndrome. Infrared thermography was performed, and the subjects were divided into seven groups according to the temperature differences between operated and unoperated sites. The thermal differences were correlated with the results from Minor's starch iodine test and the subjective symptoms questionnaire.

RESULTS

Of the 59 patients, 20 patients (33.9%) reported subjective symptoms after eating; 30 patients (50.8%) tested positive for Minor's starch iodine test, 19 patients (63.3%) of which reported subjective symptoms. Of the 29 patients who were negative for the iodine test, 2 patients (6.9%) reported subjective symptoms. Thus, subjective symptoms were well correlated with Minor's starch iodine test (r=0.589, P<0.001). As the thermal differences with infrared thermography increased, the number of patients with subjective symptoms increased (χ(2)=22.5, P<0.001). Using infrared thermography, the mean temperature difference in the positive group for the iodine test was 0.82℃±0.26℃, and that in the negative group was 0.10℃±0.47℃. With increased thermal differences, more patients showed positivity in the iodine test (χ(2)=29.9, P<0.001).

CONCLUSION

Subjective symptoms, Minor's starch iodine test, and infrared thermography are well correlated with one another. Quantitative thermography provides clues for the wide variation in the incidence of Frey's syndrome, and could be a useful method for diagnosing and studying Frey's syndrome.

Free fat grafting in superficial parotid surgery to prevent Frey's syndrome and improve aesthetic outcome

Background:

Frey's syndrome and cosmesis are important considerations in parotid surgery. Placement of an interpositional barrier can prevent these complications; however, surgical technique and efficacy remain controversial.

Methods:

A prospective case series was collected comprising all patients undergoing primary superficial parotidectomy for benign pathology with abdominal free fat grafting between June 2007 and December 2010, performed by a single surgeon. A survey was also distributed to otorhinolaryngology consultants across Australia to assess current practice.

Results:

Twenty-eight patients were included. No patient had clinical symptoms of Frey's syndrome. Seventy-five per cent of patients were completely satisfied with their aesthetic outcome, 18 per cent scored 4/5 and the remaining 7 per cent (2 patients) scored 3/5. The survey revealed that 79 per cent of respondents did not use interpositional grafts.

Conclusion:

Abdominal free fat is ideal for grafting as it is an effective, safe, simple, accessible, fast and inexpensive method of providing an interpositional graft.

Facial nerve paralysis and frey syndrome in an infant following removal of an internal mandibular distraction device

Mandibular distraction using an implantable device has become a widely accepted and utilized procedure for the treatment of retrognathia. Although excellent results have been reported and observed with distraction osteogenesis, complications such as facial nerve injury have been previously reported. Often, this injury is usually temporary and corrects over the course of time. Frey syndrome has been classically described as an injury or severance of the auricotemporal branch of the trigeminal nerve. It is commonly seen as a complication of parotid surgery and has never been reported in association with mandibular distraction. The authors report a unique case of both facial nerve paralysis and Frey syndrome in a patient following the removal of an internal mandibular distraction device. A review of the literature along with diagnosis and management are discussed.

Frey's syndrome: diagnosis in geriatric dentistry

Frey's syndrome, is characterized by warmth, flushing and sweating of the face, most of time in the preauricular region, initiated by any gustatory stimulus. It is frequently related to parotid surgery. A case of Frey's syndrome in a 81-year-old female whose long-delayed clinical onset post-parotidectomy is presented.

The sternocleidomastoid muscle flap for the prevention of Frey syndrome and cosmetic deformity following parotidectomy: A systematic review and meta-analysis

Approximately 34-86% of neoplasms of the salivary glands are located in the parotid gland and parotidectomy is the first-line treatment for parotid gland tumors. Frey syndrome and cosmetic deformity are common complications experienced by patients following parotidectomy and the sternocleidomastoid muscle flap (SCMF) is used to prevent them. Numerous studies have been performed to examine the effectiveness of the SCMF for the prevention of cosmetic deformity and Frey syndrome, however, they provide contradictory results and possess small sample sizes with consequently low statistical power. In order to evaluate the effectiveness of the SCMF for the prevention of Frey syndrome and cosmetic deformity following parotidectomy, we performed a systematic review and meta-analysis based on published randomized controlled trials (RCTs), which were identified using PubMed and CNKI databases, and references of studies up to August 2012 were included. Using these criteria, we yielded 11 RCTs. Following an independent assessment of the methodological quality of these studies and the extraction of data, a systematic review and meta-analysis was conducted. The results of the meta-analysis demonstrated that there was a significant trend towards a lower risk of objective incidence [67%; risk ratio (RR), 0.33; 95% confidence interval (CI), 0.16-0.67; P<0.01] and subjective incidence (66%; RR, 0.34; 95% CI, 0.16-0.75; P= 0.01) of Frey syndrome in the SCMF group. The sensitivity analysis also indicated that this result was significant. Due to the considerable variation between the included studies, a meta-analysis was not applicable to assess cosmetic deformity. Two RCTs demonstrated that the difference between the SCMF and no SCMF group was not statistically significant, while the other seven RCTs detected a statistically significant difference between the two groups. Publication bias was detected. In conclusion, based on currently available evidence, the use of the SCMF is benefical for the prevention of Frey syndrome, however, whether it is also benefical for cosmetic deformity remains inconclusive.

Stensen's duct injuries: the role of sialendoscopy and adjuvant botulinum toxin injection

INTRODUCTION

Stensen's duct injuries are uncommon but troublesome sequelae of facial surgery or other external traumas.

AIM

To investigate the feasibility of sialendoscopic control of Stensen's duct in iatrogenic injuries and the efficiency of botulinum toxin adjuvant therapy.

MATERIAL AND METHODS

In 2008 and 2010, 5 patients with parotid sialoceles or fistulas, infrequent complications after plastic surgery or trauma, were treated in a single institution, Poznan University of Medical Sciences ENT Department. The group consisted of 5 patients with diagnosed Stensen's duct injuries, which were post-surgery and post-traumatic sequelae. All were treated by means of open surgery. Botulinum toxin injection was administered during the procedure to decrease the saliva secretion and to improve the healing process. A sialendoscopy was performed to control the lumen of the junction after the duct injury was repaired.

RESULTS

Complete healing of the fistulas and sialoceles after the reparative surgery followed by a single botulinum toxin application was observed in all patients within 10-14 days. No side effects were noticed.

CONCLUSIONS

Our findings suggest that sialendoscopy is a valuable tool and an important step of control in the surgery of parotid duct injuries and the injection of botulinum toxin is an effective and safe second-line treatment.

Quality of life following surgical treatment of benign parotid disease

To evaluate the quality of life after surgery for benign neoplastic disease of the parotid gland. Forty-nine patients who underwent surgery for benign parotid disease between January 2004 and December 2008 were included in this retrospective study. EORTC QLQ-C30 and EORTC QLQ-H&N35 questionnaires were used to determine the quality of life. The variables of these questionnaires were compared with age, gender, educational status, histopathologic diagnosis and Frey syndrome. A statistically significant correlation was noted between the female gender and post-surgical pain, sleeplessness and the use of non-steroid anti-inflammatory drugs (p < 0.001). There was a significant difference between age and difficulties in moving the mouth (p < 0.001). Frey syndrome related to social functions, economical difficulties, speech defect, reduced sexuality, and nutritional parameters were found to be statistically significant (p < 0.001). Frey syndrome is the most common complication that affects the quality of life in patients who had parotidectomy due to a benign parotid disease. Therefore, all patients should be informed about Frey syndrome before parotidectomy.

Pleomorphic adenoma of the parotid: formal parotidectomy or limited surgery?

BACKGROUND

Optimal surgery for pleomorphic adenoma of the parotid is controversial. In the present review, we discuss the advantages and disadvantages of the various approaches after addressing the surgical pathology of the parotid pleomorphic adenoma capsule and its influence on surgery.

DATA SOURCES

PubMed literature searches were performed to identify original studies.

CONCLUSIONS

Almost all pleomorphic adenomas can be effectively treated by formal parotidectomy, but the procedure is not mandatory. Extracapsular dissection is a minimal margin surgery; therefore, in the hands of a novice or occasional parotid surgeon, it may result in higher rates of recurrence. Partial superficial parotidectomy may be a good compromise. The tumor is removed with a greater cuff of healthy parotid tissue than in extracapsular dissection. This may minimize the recurrence rate. On the other hand, the removal of healthy parotid tissue compared with formal parotidectomy is limited, thus minimizing complications such as facial nerve dysfunction and Frey syndrome.

Salivary gland carcinomas

INTRODUCTION

Salivary gland carcinomas are rare tumours of heterogeneous morphology that require distinctive surgical and adjuvant therapy.

METHODS

Relevant studies were electronically searched in PubMed and reviewed for innovative and important information.

RESULTS

Recent insights in genetic alterations like chromosomal aberrations, expression of receptor tyrosine kinases, malfunction of tumour suppressor genes or DNA promoter methylations increased the knowledge about aetiology and pathogenesis. New histological subtypes are recognised, and a three-tiered grading system seems reasonable. Ultrasound remains the basic diagnostic imaging procedure. New developments comprise the diffusion-weighed magnetic resonance imaging, while fluorodeoxyglucose positron emission tomography/computed tomography shows good diagnostic accuracy in detecting distant metastases and local recurrence. Fine-needle aspiration cytology helps in differentiating a neoplasia from a non-neoplastic lesion while being unreliable in recognising malignancy. In contrast, additional core needle biopsy and/or intraoperative frozen section diagnosis increase the accuracy in diagnosing a malignant lesion. Conservative parotid surgery with nerve monitoring remains state-of-the-art. Free flaps or musculoaponeurotic flaps are proposed for prevention of Frey's syndrome. As parotid cancer often shows skip metastases, complete ipsilateral neck dissection (level I-V) is indicated particularly in high-grade lesions. Adjuvant radio(chemo)therapy increases local tumour control, whereas overall survival is not necessarily improved. Current results of systemic chemotherapy or targeted therapy in advanced tumour stages are disappointing.

CONCLUSION

Despite several developments, salivary gland carcinomas remain a heterogeneous group of tumours challenging both pathologists and clinicians.