Use of allogenic acellular dermal matrix in prevention of Frey's syndrome after parotidectomy

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.

Risk factors for sialocele after parotidectomy: Does tumor size really matter?

OBJECTIVE

Sialocele that develops after parotid surgery often prolongs the treatment period and stresses both the surgeon and patient. The extent of surgery and tumor size are known to be associated with sialocele occurrence. We investigated the incidence of post-parotidectomy sialocele and the associated risk factors, with a focus on tumor size.

METHODS

We retrospectively reviewed the medical records of 172 patients who underwent parotidectomy between January 2013 and May 2020 at Haeundae Paik Hospital, Inje University of Korea. We stratified patients into those with and without sialocele (fluid collection in the operative bed). We compared clinical data, patient demographics, and surgical details; we identified risk factors for sialocele development after parotid surgery.

RESULTS

Seventeen patients were diagnosed with post-parotidectomy sialocele (9.88%; 17/172). Univariate logistic regression revealed that the male sex, deep lobe tumor location, and large tumor size were significantly associated with postoperative sialocele (p = 0.015, 0.009, and 0.016, respectively). We subjected these parameters to multivariate analyses; the odds ratios were 3.70, 3.58, and 2.34, respectively. Receiver operating characteristic curve analyses showed that a tumor size > 2.50 cm was the optimal cutoff in terms of predicting post-parotidectomy sialocele.

CONCLUSION

Male sex, a tumor in the deep lobe, and large tumor size were strongly associated with increased risk for sialocele after parotidectomy. Tumor size > 2.50 cm serves as the cutoff identifying patients likely to experience sialocele after parotid surgery.

Comparison of the use of allogenic acellular dermal matrix on rates of Frey syndrome post parotidectomy: A systematic review and meta-analysis

OBJECTIVE

The aim of this study was to evaluate the efficacy of acellular dermal matrix (ADM) use in reducing Frey syndrome (FS) rates in patients postparotidectomy.

STUDY DESIGN

We performed a systematic review and meta-analysis of existing literature comparing rates of FS with and without ADM use.

RESULTS

Eight studies were shortlisted for qualitative study, of which 7 compared rates of FS with and without the use of ADM. A total of 211 patients underwent parotidectomy with the use of ADM. Of these, mean patient age was 44.7 (SD ± 7.2); 89 of 159 were pleomorphic adenoma (55.9%), 29 of 159 with histological diagoses stated were Warthin's tumor (18.2%), and 159 of 211 were other histologic diagnoses (25.7%). Subjective and objective incidence rates for FS were 23 of 211 (10.9%) and 7 of 211 (3.3%), respectively. Patients in whom ADM barriers were used had significantly lower rates of subjective and objective FS (relative risk = 0.22; 95% confidence interval, 0.09-0.57; P = .002; and relative risk = 0.07; 95% confidence interval, 0.07-0.33; P < .001), respectively, compared to patients with no ADM.

CONCLUSION

The use of ADM was associated with lower FS rates compared to no ADM and should be considered in routine use to prevent this condition.

The Progress of Decellularized Scaffold in Stomatology

The oral and maxillofacial region contains oral organs and facial soft tissues. Due to the complexity of the structures and functions of this region, the repair of related defects is complicated. Different degrees of defects require different repair methods, which involve a great combination of medicine and art, and the material requirements are extremely high. Hence, clinicians are plagued by contemporary oral repair materials due to the limitations of bone harvesting, immune rejection, low osteogenic activity and other problems. Decellularized extracellular matrix has attracted much attention as a bioactive scaffold material because of its nonimmunogenic properties, good osteogenic properties, slow release of growth factors, promotion of seed cell adhesion and maintenance of stem cell characteristics. This article reviews the sources, preparation methods, application and research progress of extracellular matrix materials in the repair of oral and maxillofacial defects to provide an overview for fundamental research and clinical development.

Regenerative medicine for end-stage fibrosis and tissue loss in the upper aerodigestive tract: a twenty-first century review

OBJECTIVE

This review assesses regenerative medicine of the upper aerodigestive tract during the first two decades of the twenty-first century, focusing on end-stage fibrosis and tissue loss in the upper airways, salivary system, oropharynx and tongue.

METHOD

PubMed, Embase, Google Scholar, Cochrane Library, Medline and clinicaltrials.org were searched from 2000 to 2019. The keywords used were: bioengineering, regenerative medicine, tissue engineering, cell therapy, regenerative surgery, upper aerodigestive tract, pharynx, oropharynx, larynx, trachea, vocal cord, tongue and salivary glands. Original studies were subcategorised by anatomical region. Original human reports were further analysed. Articles on periodontology, ear, nose and maxillofacial disorders, and cancer immunotherapy were excluded.

RESULTS

Of 716 relevant publications, 471 were original studies. There were 18 human studies included, within which 8 reported airway replacements, 5 concerned vocal fold regeneration and 3 concerned salivary gland regeneration. Techniques included cell transplantation, injection of biofactors, bioscaffolding and bioengineered laryngeal structures.

CONCLUSION

Moderate experimental success was identified in the restoration of upper airway, vocal fold and salivary gland function. This review suggests that a shift in regenerative medicine research focus is required toward pathology with a higher disease burden.

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.

Effect of human acellular dermal matrix (Megaderm™) on infra-auricular depressed deformities, Frey's syndrome, and first bite syndrome following parotidectomy: a multi-center prospective study

Background

Parotidectomy is the primary treatment for parotid gland tumors. However, complications may include a prominent facial scar or infra-auricular depressed deformity, Frey's syndrome, first bite syndrome, or other facial pain, numbness, and paralysis. Acellular dermal matrix (ADM) has been widely used to prevent these complications in parotid surgery, but there have been no prospective, multi-center trials documenting its efficacy. This study evaluates the effectiveness of ADM implantation in preventing infra-auricular depressed deformity, Frey's syndrome and first bite syndrome after parotidectomy.

Methods

We analyzed 51 cases of standard parotidectomy and 58 cases of parotidectomy with implantation of Megaderm™ ADM through prospective multicenter trial. Acute complications including infection, seroma, hematoma, skin necrosis, and acute parotid area pain were evaluated 1 week postoperatively. Clinician grading of Frey's syndrome and blinded clinician evaluation of infra-auricular depressed deformities were conducted at 3, 6, and 12 months. Patients evaluated subjective satisfaction with neck appearance, Frey's syndrome quality, and acute parotid area pain at 3, 6, and 12 months.

Results

There was a higher incidence of seroma in the Megaderm™ group than in the control group at week 1. The incidence and total clinician-evaluated Frey's syndrome scores were significantly lower in the Megaderm™ group than in the control group at 3, 6, and 12 months. Both the objective and subjective evaluations of the facial contour showed a better outcome in the Megaderm™ group compared to the control group at 3, 6, and 12 months. There were no significant differences between the groups in the patient-reported Frey's syndrome quality scores at 3, 6, and 12 months, but the Megaderm™ group reported significantly less acute pain than the control group.

Conclusions

ADM implantation can effectively reduce the occurrence of Frey's syndrome, infra-auricular depressed deformity, and first bite syndrome after parotidectomy. ADM may be especially advantageous in complex parotidectomy cases when significant complications are expected.

Different Surgical Strategies in the Prevention of Frey Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE/HYPOTHESIS

To define the best surgical technique able to reduce Frey syndrome (FS) incidence after parotidectomy.

STUDY DESIGN

Systematic review and network meta-analysis.

METHODS

An arm-based network analysis was conducted using a Bayesian hierarchical model. The primary and secondary outcomes were the incidence of subjective (clinical) and objective (positive starch-iodine test result) FS, respectively.

RESULTS

A total of 3830 patients with a median age of 50.35 years (n = 2323; IQR 44.25-54.18) were included for six interventions [temporoparietal fascia (TPFF), free fat graft (FFG), acellular dermal matrix (ADM), sternocleidomastoid muscle (SCM) flap, and superficial musculoaponeurotic system (SMAS) flap]. If compared to no treatment, the greatest reduction of subjective (clinical) FS incidence was measured for the TPFF (OR: 0.07, CI: 0.004-0.57), the ADM (OR: 0.09, CI: 0.02-0.35), and the FFG (OR: 0.11, CI: 0.03-0.42) techniques. However, a significant difference was measured also for the SCM flap (OR: 0.38, CI: 0.18-0.73) and for the SMAS flap (OR: 0.42, CI: 0.19-0.97). All treatments showed a significant reduction of the objective FS incidence if compared to no treatment (FFG, OR: 0.06, CI: 0.002-0.62; TPFF, OR: 0.07, CI: 0.01-0.33; ADM, OR: 0.11, CI: 0.03-0.44; SMAS, OR: 0.36, CI: 0.17-0.71; SCM, OR: 0.40, CI: 0.19-0.74).

CONCLUSIONS

TPFF, ADM, and FFG seem to be the best treatment strategies to prevent FS after parotidectomy. Further randomized controlled trials comparing these techniques should be conducted to define specific indications. Laryngoscope, 131:1761-1768, 2021.

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.

Minor Parotidectomy Complications: A Systematic Review

OBJECTIVES

To report descriptive statistics for minor parotidectomy complications.

METHODS

A systematic review was performed, selecting 235 studies for analysis. The incidence of complications was tabulated, and descriptive statistics calculated. Outlier studies, 1 standard deviation above the mean, were reexamined to determine potential causal factors for each complication. All studies were examined for statistically significant differences for any potential causal factor.

RESULTS

The pooled incidence of minor complications reported were hematoma 2.9% (95% confidence interval [CI]: 2.4-3.5), wound infection 2.3% (95% CI: 1.8-2.9), sialocele 4.5% (95% CI: 3.5-5.7), salivary fistula 3.1% (95% CI: 2.6-3.7), flap necrosis 1.7% (95% CI: 1.1-2.5), scar issues 3.6% (95% CI: 2.4-5.4), numbness 33.9% (95% CI: 25.6-43.4), and deformity 11.8 (95% CI: 6.9-19.5). Implants result in more wound complications, such as hematoma, sialocele, or salivary fistula. Sialocele and salivary fistula appear more frequently after less extensive parotid surgery, whereas hematoma, wound infections, flap necrosis, and aesthetic considerations are worse with more extensive resections.

CONCLUSIONS

Minor parotidectomy complications are more frequent than generally assumed and related to certain factors that should be investigated. Laryngoscope, 131:571-579, 2021.

Cold knife dissection and bipolar diathermy Vs harmonic scalpel in parotid gland surgery for benign tumours

INTRODUCTION

Surgical techniques for extirpation of tumours of the parotid gland have evolved significantly in recent years. Previous data suggest the use of Harmonic Scalpel reduced operative time, intraoperative blood loss, postoperative drain production, and incidence of facial nerve injury, in comparison to cold scalpel dissection MATERIAL AND METHODS: retrospective analysis of 2group of patients operated using harmonic scalpel versus cold knife dissection and bipolar diathermy and compare operative time and post-surgical complication rate:, facial nerve injury, sialocele or salivary fístula formation, after parotidectomy for benign parotid tumours.

RESULTS

108 patients were included. Regarding surgical time, the mean time to using Harmonic Scalpel was 114±39 (Min: 60/Max: 240), and the mean time using bipolar diathermy was 135±38 (Min: 90/Max: 285) and this was the only significant difference between the 2techniques (p=.049).

CONCLUSIONS

Harmonic scalpel is a safe and effective tool to perform parotid surgery in benign tumours. However, a shorter surgical time was the only advantage found over the traditional cold dissection and bipolar dissection method.

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.

Transthoracic Pulmonary Artery Denervation for Pulmonary Arterial Hypertension

Objective—

Pulmonary arterial hypertension is characterized by progressive pulmonary vascular remodeling and persistently elevated mean pulmonary artery pressures and pulmonary vascular resistance. We aimed to investigate whether transthoracic pulmonary artery denervation (TPADN) attenuated pulmonary artery (PA) remodeling, improved right ventricular (RV) function, and affected underlying mechanisms. We also explored the distributions of sympathetic nerves (SNs) around human PAs for clinical translation.

Approach and Results—

We identified numerous SNs in adipose and connective tissues around the main PA trunks and bifurcations in male Sprague Dawley rats, which were verified in samples from human heart transplant patients. Pulmonary arterial hypertensive rats were randomized into TPADN and sham groups. In the TPADN group, SNs around the PA trunk and bifurcation were completely and accurately removed under direct visualization. The sham group underwent thoracotomy. Hemodynamics, RV function, and pathological changes in PA and RV tissues were measured via right heart catheterization, cardiac magnetic resonance imaging, and pathological staining, respectively. Compared with the sham group, the TPADN group had lower mean pulmonary arterial pressures, less PA and RV remodeling, and improved RV function. Furthermore, TPADN inhibited neurohormonal overactivation of the sympathetic nervous system and renin-angiotensin-aldosterone system and regulated abnormal expressions and signaling of neurohormone receptors in local tissues.

Conclusions—

There are numerous SNs around the rat and human main PA trunks and bifurcations. TPADN completely and accurately removed the main SNs around PAs and attenuated pulmonary arterial hypertensive progression by inhibiting excessive activation of the sympathetic nervous system and renin-angiotensin-aldosterone system neurohormone-receptor axes.

Optimizing the Aesthetic Result of Parotidectomy with a Facelift Incision and Temporoparietal Fascia Flap

The 3 most common problems after a parotidectomy are cheek contour deformity, Frey syndrome (gustatory sweating), and a visible scar on the neck. These problems can potentially be prevented by (1) facelift type incisions, which eliminate the neck incision and (2) interposition of temporoparietal fascia at the parotidectomy site that fills the defect and provides a barrier to aberrant neuronal regeneration. We followed 11 patients who underwent parotidectomy (9 superficial and 2 total parotidectomies) for a variety of parotid tumors between December 2001 and January 2018. Facelift type incisions were used in all patients, and temporoparietal fascia flaps were used to fill the parotidectomy defects. The last 6 patients were tested for objective evidence of Frey syndrome with the Minor Starch Iodine test. Patients were then followed for up to 7 years (11 months to 7 years, average 3 years). All patients had well-hidden scars and good contour of the cheeks. None of the patients developed subjective or objective evidence of Frey syndrome. This small series suggests that the aesthetic result after parotidectomy can be improved by using a facelift incision and placement of a temporoparietal fascia flap into the parotidectomy defect. Additionally, the tissue barrier thus provided may also help to prevent Frey syndrome.

Mixed Tumor in Deep Lobe and Versatility of Acellular Dermal Matrix

Frey's syndrome and infra-auricular depressed deformities are the ones of the most common complications that can occur after total parotidectomy. We report 1 case of pleomorphic adenoma occurred in the deep lobe that obtained good results from using acellular dermal matrix (ADM) after total parotidectomy. A 24-year-old man visited the hospital with oval shape mass in right mandibular angle which of 4 cm in size was found in the deep lobe of right parotid gland from Magnetic resonance imaging scanning and a pleomorphic adenoma was suspected. A total parotidectomy was performed while preserving the facial nerve. The material known as ADM were placed in the depressed part from where the mass was removed, and the site was sutured. The surgery site was healed well without any complications such as Frey's syndrome or infra-auricular depressed deformities. The pathological result was confirmed as pleomorphic adenoma. In addition to these advantages, it does not have little potential of deformation by the gravity after the surgery, and there is no restraint on circulation, which makes fabrication free and each deformation into various shapes can be described as another advantage of the reconstruction using the ADM.

Auriculotemporal Syndrome (Frey Syndrome)

Frey syndrome is a common sequela of parotidectomy, and although it is not frequently manifested clinically, it can cause significant morbidity for those affected. Frey syndrome results from synkinetic autonomic reinnervation by transected postganglionic parasympathetic nerve fiber within the parotid gland to the overlying sweat glands of the skin. Many surgical techniques have been proposed to prevent the development of Frey syndrome. For those who develop clinical symptoms of Frey syndrome, objective testing can be performed with a Minor starch-iodine test. Some of the current methods to prevent and treat symptomatic Frey syndrome are reviewed.

Frey's Syndrome Consequent to an Unusual Pattern of Temporomandibular Joint Dislocation: Case Report with Review of Its Incidence and Etiology

Frey's syndrome was first described in the 18(th) century. Recognizing it as a nonspecific condition, the symptom of gustatory sweating in patients with parotid gland inflammation was described by Duphenix and Baillarger. However, as a specific diagnostic entity, gustatory sweating, following trauma to parotid glands, was first described by Polish neurologist Lucie Frey, in 1923, and hence he proposed the term auriculotemporal syndrome. The condition is characterized by sweating, flushing, a sense of warmth, and occasional pain in the preauricular and temporal areas, following the production of a strong salivary stimulus. Several etiologies of Frey's syndrome have been mentioned in the literature; however, none attribute dislocation of the "intact" mandibular condyle as a cause of the syndrome. Reviewing its pathophysiology, etiology, and incidence in detail, we describe a case of Frey's syndrome subsequent to superolateral dislocation of the intact mandibular condyle following fracture of the anterior mandible. Its management and prevention are also discussed in brief.

Application of acellular dermal matrix in reconstruction of oral mucosal defects in 36 cases

PURPOSE

Artificial grafts have been investigated for use in the repair of oral mucosal defects. The aim of this retrospective study was to present the outcomes of the use of acellular dermal matrix (ADM) grafts to repair oral mucosal defects.

MATERIALS AND METHODS

Data from 36 patients with oral mucosal defects reconstructed with ADM grafts from 2003 through 2009 were reviewed. All patients were followed-up for at least 6 months to observe the graft repair, wound-healing time, contracture, color, infection, pain, immunologic reaction, texture of the graft, and clinical course. Graft success was defined as the ADM graft being replaced by new mucosa-like tissue and the oral mucosal defect being covered with the new mucosa-like tissue. Any evidence of incomplete graft re-epithelialization or graft sloughing was considered a graft failure (complete or incomplete).

RESULTS

Of the 36 cases, 34 grafts (94.4%) were successfully replaced with new mucosa-like tissues and only 2 grafts (5.6%) failed. No complaints such as pain, immunologic reaction, or infection were observed during the follow-up. Mild graft contraction occurred in 7 patients with lip or buccal defects, especially at approximately 3 to 5 weeks after the reconstructive surgery.

CONCLUSIONS

The ADM grafts for oral mucosal defects were safe and effective. The present data support the clinical application of ADM grafts in reconstructing oral mucosal defects caused by various oral diseases.

Graft for prevention of Frey syndrome after parotidectomy: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

To detect the effect and safety of different types of grafts for the prevention of Frey syndrome after parotidectomy.

MATERIALS AND METHODS

The following data bases were searched electronically: MEDLINE (using OVID, from 1948 to July 2011), Cochrane Central Register of Controlled Trials (CENTRAL, issue 2, 2011), EMBASE (available from: http://embase.com, 1984 to July 2011), World Health Organization International Clinical Trials Registry Platform (July 2011), Chinese BioMedical Literature Database (1978 to July 2011), and the China National Knowledge Infrastructure (1994 to July 2011). The relevant journals and reference lists of the included studies were manually searched for randomized controlled trials studying the effect and safety of different types of grafts for preventing Frey syndrome after parotidectomy. The risk of bias assessment using Cochrane Collaboration's tool and data extraction was independently performed by 2 reviewers. The meta-analysis was performed using Review Manager, version 5.1.

RESULTS

A total of 14 randomized clinical trials and 1,098 participants were included. All had an unclear risk of bias. The meta-analysis results showed that the use of an acellular dermis matrix can reduce by 82% the risk of Frey syndrome compared with the no-graft group using an objective assessment (relative risk [RR] 0.18, 95% confidence interval [CI] 0.12 to 0.26; P < .00001; Grading of Recommendations, Assessment, Development, and Evaluation [GRADE] quality of evidence: high). The acellular dermis matrix can also reduce by 90% the risk of Frey syndrome compared with the no-graft group using a subjective assessment (RR 0.10, 95% CI 0.05 to 0.22; P < .00001; GRADE quality of evidence: high). The muscle flaps can reduce by 81% the risk of Frey syndrome compared with the no-graft group (RR 0.19, 95% CI 0.13 to 0.27; P < .00001; GRADE quality of evidence: high). No statistically significant difference was found between the acellular dermal matrix and muscle flap groups (RR 0.73, 95% CI 0.15 to 3.53, P = .70; GRADE quality of evidence: low). No serious adverse events were reported.

CONCLUSIONS

The present clinical evidence suggests that grafts are effective in preventing Frey syndrome after parotidectomy. More randomized clinical trials are needed to confirm our conclusions and prove the safety of the grafts.

AlloDerm implants for prevention of Frey syndrome after parotidectomy: a systematic review and meta-analysis

Although Frey syndrome is not life-threatening, it is identified as the most serious and widely recognized sequela of parotidectomy and has significant potential negative social and psychological implications. Several studies have investigated whether AlloDerm® implants prevent Frey syndrome effectively and safely, however, the conclusions are inconsistent. We aimed to evaluate the precise effectiveness of AlloDerm implants for preventing Frey syndrome after parotidectomy, using a systematic review and meta-analysis. We searched randomized and quis-randomized controlled trials in which AlloDerm implants were compared to blank controls for preventing Frey syndrome after parotidectomy, from the PubMed, Embase, the Cochrane Library and the ISI Web of Knowledge databases, without any language restriction. Two reviewers independently searched, identified, extracted data and assessed methodological quality. Relative risks with 95% confidence intervals were calculated and pooled. Five articles involving 409 patients met the inclusion criteria. Meta-analyses showed a significant 85% relative risk reduction in objective incidence (RR=0.15, 95% CI 0.08-0.30; P<0.00001) and 68% in subjective incidence (RR=0.32, 95% CI 0.19-0.57; P<0.00001) of Frey syndrome with AlloDerm implants; there was a significant 91% relative risk reduction in salivary fistula (RR=0.09, 95% CI 0.01-0.66; P=0.02); there was no statistical significance for the incidence of facial nerve paralysis (RR=0.96, 95% CI 0.84-1.09; P=0.51); there was no statistical significance for the incidence of seroma/sialocele (RR=1.36, 95% CI 0.66-2.80; P=0.40); there was a trend for a small effect in improving facial contour. Adverse events related to AlloDerm implants were not found. There is evidence that AlloDerm reduces the incidence of Frey syndrome effectively and safely, and also has the potential to improve facial contour and decrease salivary fistula. However, it is unclear whether AlloDerm implants improve facial contour and decrease other complications. Thus, further controlled evaluative studies incorporating more precise measures are required.

[Management of the surgical pathology of the parotid gland: A review of 54 cases]

INTRODUCTION AND AIM OF THE STUDY

The management of the surgical pathology of the parotid gland and its results are relatively uniform. However, both in the diagnostic and the therapeutic aspects, there are some controversial issues which we discuss from the point of view of recent experience at our department.

METHODS

A descriptive and retrospective study was conducted on patients who underwent parotidectomy for any indication between July 2004 and June 2009 (5 years).

RESULTS

Fifty four parotidectomies were performed in 52 patients. CT was the most commonly used preoperative diagnostic imaging study. The accuracy of FNAB was 93.3%. 76% were benign processes; among them 7.3% with inflammatory causes. All of the surgical procedures from April 2005 onwards were performed with electrophysiological monitoring of the facial nerve. Superficial parotidectomy was performed in 75.6% of benign cases. The incidence of transient facial paresis in benign pathologies was of 14.6% (all of them of grades II and III). Two cases (both with total parotidectomy) had permanent facial mobility sequelae. The rhytidectomy incision was used preferentially in young women.

CONCLUSIONS

The controversial issues identified, due either to discrepancies or lack of enough evidence, were: the diagnostic role of MRI, the validity and usefulness of FNAB, the indications of surgical treatment, the need for facial nerve monitoring and the consideration of cosmetic aspects, in particular the indications of rhytidectomy incision.