If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
Address reprint requests and correspondence: Phillip K. Pellitteri, DO, FACS, Department of Otolaryngology/Head & Neck Surgery, Guthrie Health System, Geisinger Commonwealth School of Medicine One Guthrie Square, Sayre, PA 18840.
Frey syndrome (gustatory sweating) is a common and often times significant consequence of parotid gland surgery. The classic signs and symptoms include facial sweating, flushing, rubor, and sensation of heat over the preauricular region during oral stimulation. These clinical findings may provoke quality of life changes, and thus, are considered significant. Both surgical and nonsurgical treatment modalities have been advanced in the treatment of this disorder. Surgical treatment is aimed at prevention of the development of Frey syndrome and consists of a constellation of techniques which are designed to interpose tissue in the parotid surgical bed to act as a barrier to prevent aberrant parasympathetic fiber ingrowth and innervation to facial skin eccrine sweat glands. These techniques include: limiting the extent of parotid surgery when possible, use of local tissue as advancement or rotational flaps, autologous transfer of tissue, and use of allograft material.
Superficial parotidectomy is a well-established and effective surgical procedure for early stage neoplasms involving the lateral lobe of the parotid gland. The traditional parotidectomy results in several untoward consequences attributed to the anatomy of the parotid gland relative to the proximity of facial skin and the procedural effects of parotid gland removal: (1) cosmetic asymmetry due to volume loss; (2) incisional scarring about the face and neck; and (3) Frey syndrome (gustatory sweating). A number of methods have been advanced to remedy these consequences, singly or in combination. This discussion will focus on those methods designed to prevent Frey syndrome after parotidectomy, and, in many circumstances, synchronously address cosmetic deformity due to volume loss.
Frey syndrome is the term given to the pathophysiologic finding of post-parotidectomy sweat gland activity in the region of facial skin overlying the surgical parotid bed, prompted by oral consumption of foods, liquids, or the thought of same. The inferior salivatory nucleus gives rise to preganglionic parasympathetic fibers that run with the glossopharyngeal nerve, the tympanic nerve, and lesser petrosal nerve ultimately synapsing in the otic ganglion. Postganglionic fibers become part of the auriculotemporal nerve supplying secretory motor stimulation to the parotid gland. These nerves also cause vasodilation of parotid microvasculature.
Frey syndrome arises as a result of regenerated parasympathetic innervation of eccrine facial skin sweat glands by aberrant fibers from residual parotid bed salivary tissue. The autonomic gustatory initiation of impulses in these parasympathetic fibers, prompted by oral stimulus, result in the innervation of eccrine gland release of sweat, manifested as perspiration in the affected area of facial skin. The incidence and problematic effect is variable in patients undergoing parotidectomy and may be related to the amount of residual salivary tissue within the surgical bed. It represents the most frequent complication following parotid surgery, usually appearing within a year after operation, and occurring in 10%-40% of patients.
The main clinical manifestations of Frey syndrome include sweat, heat, and rubor in the affected facial skin following oral stimulus, first described by Lucie Frey in 1923 and termed auriculotemporal syndrome.
A number of nonsurgical remedies have been advocated for symptomatic treatment of this effect, including the application of anticholinergic agents, cosmetics, antiperspirant compounds, and injection of botulinum toxin to the affected area of facial skin, all with varying degrees of success.
Initial surgical options for treatment, performed postoperatively, have included: re-elevation of the facial flap with interposition graft placement and transcanal tympanic neurectomy.
In particular, facial flap re-elevation carries significant risk of flap necrosis and possible facial nerve injury. A number of surgical procedures, performed at the time of parotidectomy, have been advanced for prevention of the syndrome, many of which also address the problem of cosmetic deformity following volume loss secondary to tumor removal. A discussion of these preventive techniques follows.
Surgical techniques
Local and/or regional tissue advancement
One of the earliest surgical techniques used to prevent Frey syndrome was the superficial musculoaponeurotic system interposition flap or, SMAS flap.
The flap is designed as an interposition tissue advancement which prevents aberrant ingrowth of parasympathetic fibers into apocrine sweat glands in skin. The flap is constructed by dissection of the SMAS plane from parotid glandular capsular tissue, deep to the subcutaneous fat layer, and maintained in continuity with the platysma. Following completion of parotid tumor resection, the flap is reapproximated to the pretragal connective tissue using suture technique. This flap is generally contraindicated in malignant parotid tumors which require more oncological safety in resection of tissue to achieve negative margin status. Potential problems associated with this flap include facial cosmetic defect, skin injury secondary to flap harvesting, delayed skin necrosis, and less donor tissue available for coverage.
Another technique which exploits the use of regional tissue is the sternocleidomastoid muscle transposition flap, or, SCM flap
(Figure 1A, B). This technique takes advantage of the availability of regional tissue accessible through the planned parotidectomy incision which can be harvested easily, with minimal donor site complications. The SCM flap is a muscle flap which is transposed from a point inferior to the parotid bed superiorly into the bed and approximated to the anterior peripheral parotid-masseteric fascia later to reconstitute tissue bulk in the parotid bed. The flap is harvested from the anterior sternal head of the superior portion of the muscle and requires protection of the spinal accessory nerve. The flap is based on the occipital arterial supply to the superior third of the SCM and has the advantage of greater bulk and coverage than the SMAS flap, thus providing both mechanical obstruction to aberrant parasympathetic fiber growth into skin and minimizing tissue deformity secondary to volume loss
(Figure 2A, B). The potential complications of flap harvesting and rotation are few, potentially involving injury to the spinal accessory nerve during muscle transection inferiorly.
The temporoparietal fascia flap is another technique which capitalizes on regional tissue advancement to mechanically obstruct aberrant parasympathetic fiber ingrowth in the prevention of Frey syndrome.
The flap is thin, vascularized, and rotationally mobile. The flap is harvested through a hairline incision which exposes the superior border of the temporalis muscle, with elevation of the fascia protecting the superficial temporal vessels (Figure 3A). The flap is then folded and transposed over the zygomatic arch to be approximated posteriorly to the SCM fascia and anteriorly to the peripheral parotid bed into the SMAS (Figure 3B). Although a pliable flap providing adequate bed surgical bed coverage, it does not provide sufficient bulk for larger cosmetic deformities due to volume loss. The temporal branch of the facial nerve is at risk during this flap elevation.
Figure 3(A) Temporoparietal fascia flap (TPF) design for parotidectomy defect.
The flap is designed as a muscle flap which is readily accessible through the parotidectomy incision. Initial steps in the procedure include elevation of the facial skin flap superficial to the platysma muscle. The flap is based superiorly and is harvested by dissection in a posterior to anterior direction until the amount of surface area coverage is achieved. It is then elevated to the level of the mandible with attempts to preserve as many perforating vessels as possible. The platysma muscle is then either rotated superoposteriorly or flipped over the mandible, depending on the location of the defect, and sutured to the neighboring peripheral fascia. The main potential complications associated with this technique include injury to the marginal mandibular nerve and risk of skin flap necrosis.
Free tissue applications
Techniques utilizing the application of free tissue as an interpositional barrier have been described for prevention of Frey syndrome and reconstitution of contour deformity after parotidectomy. These include: free fat grafting
; and autologous free tissue transfer with microvascular reconstitution, with the latter technique described for reconstruction following extensive parotid and/or cranial base resection.
Fat is harvested and layered into the parotid bed defect, followed by closure. This technique has the advantage of providing bulk sufficient to overcome contour deformity from lateral parotid lobe removal, as well as minimal time required in harvesting and applying the graft. Disadvantages include remotely located donor sites and the possibility of fat resorption or graft infection.
Combination grafts consisting of both fat and dermis, so called dermofat grafts, have been utilized as interposition barriers in the parotid surgical bed.
In this procedure, fat is harvested from the buttock in one layer with overlying dermis in order to prevent fat necrosis and provide bulk for reconstitution of the parotid bed. The dermal portion of the flap is then sutured to the SMAS in the anterior parotid bed and the SCM fascia posteriorly. Flap design and size may be modified according to necessary coverage required in the parotid bed. The flap has been reported to offer both reduction of contour deformity as well as prevention of Frey syndrome. Additionally, in contrast to autologous fat grafts, the dermofat graft is associated with less fat resorption and increased potential for correction of depression deformity.
Techniques utilizing allograft material have been advanced for the prevention of Frey syndrome and correction of contour deformity following superficial and total parotidectomy
. The most popular material employed is that of acellular dermal matrix (ADM), which is produced through a freeze drying process utilizing human donor dermal specimens which have been cleared of allogenic cellular constituents and have been harvested from donors free of transmittable infectious disease (eg, viral hepatitis, HIV).
The material is readily available and very adaptive to most, if not all, parotid bed defects. It has been employed for reconstitution of large parotid defects in total parotidectomy where multiple ADMs may be implanted to correct the defect and simultaneously serve as an interpositional barrier for the prevention of Frey syndrome (Figure 4). The ADM caliber most adaptive and of greatest utility is labeled as the “thick” product. A modification of this technique utilizes a combination of a posteriorly pedicled SMAS flap and ADM for reconstitution of volume loss and prevention of Frey syndrome after total parotidectomy.
In this modification, the ADM is first placed into the defect and surrounding surgical bed for coverage, followed by the infolding of the pedicled SMAS flap for volume loss correction. Techniques utilizing ADM offer the advantage of optimal sizing for coverage, as well as not requiring a separate donor site or other tissue harvesting procedure.
Figure 4Acellular dermal grafts used for parotidectomy defect reconstitution.
Many authors believe that the extent of surgery is the best method of controlling Frey syndrome. Logically, the less parotid tissue resected the less likely aberrant innervation of eccrine glands by auriculotemporal nerve branches will occur.
This is likely due to less exposure of the nerve, as well as the presence of more residual parotid tissue with an intact capsule to hinder aberrant growth. Data from series of patients undergoing partial parotidectomy show decreased rates of Frey syndrome than in patients undergoing standard superficial parotidectomy.
Frey syndrome can be minimized by raising thick skin flaps as opposed to very thin flaps (hair follicle exposure) although the evidence for this is scarce.
There have been a number of investigations detailing outcomes of various techniques to prevent Frey syndrome following parotidectomy. Most of these investigations report case studies or other uncontrolled, nonrandomized experiences with numbers insufficient to make meaningful comparisons between techniques.
The effectiveness of sternocleidomastoid flap versus superficial musculoaponeurotic system flap for the prevention of Frey syndrome and facial depressed deformity in parotid surgery for pleomorphic adenoma.
The metric assigned for evaluation was subjective patient questionnaire together with performance of a starch iodine test in most assessments. A long-term investigation examining the occurrence of Frey syndrome after SMAS flap reconstruction as compared with a cohort of patients where no reconstruction was performed yielded the finding of delayed onset and reduced intensity and extent of effect in patients receiving SMAS reconstruction.
However, ultimately, the study did not demonstrate a measurable difference in prevention of the syndrome between cohorts. A larger study examining multiple published reports, including 2 randomized controlled trials, on use of the SCM flap for parotid bed reconstitution yielded no conclusive evidence indicating that the flap prevented Frey syndrome.
Most of the evaluated study results from this investigation suggested an improvement in Frey syndrome by the authors, but no subjective improvement as reported by the patients. Scattered reports evaluating other tissue advancement techniques have been observational cases studies or anecdotal results reporting with insufficient numbers and no controls for comparison.
The effectiveness of ADM in preventing Frey syndrome was investigated in a review which conducted a meta-analysis on reported clinical randomized controlled trials.
The overall finding was that use of ADM could effectively prevent Frey syndrome after parotidectomy, and that this technique was safe and resulted in few complications. However, the authors correctly point out vulnerabilities in the review: sample size was comparatively small, types of ADM were often not specified and the description of neoplastic disease, benign vs malignant, was not consistently specified. Long-term evaluation of free tissue transfer effectiveness in preventing Frey syndrome has not been investigated systematically. Advocates of this type of reconstruction have noted that free flap interposition, and specifically anterolateral thigh flap, provides superior contour defect restoration, especially following total parotidectomy.
Frey syndrome may occur in a significant proportion of patients following parotid surgery and may be sufficiently symptomatic such as to alter quality of life. Although nonsurgical options for treatment may be symptomatically effective in the short term, none are designed to eradicate the problem. A number of surgical techniques, applied at the time of parotidectomy, have been used to prevent the occurrence of Frey syndrome, including: local and/or regional advancement of tissue; autologous tissue transfer, and the use of allograft material, all designed to create an interposition barrier to prevent ingrowth of aberrant parasympathetic fibers into sweat glands. Most of these techniques also provide for varying degrees of volume loss reconstitution in order to minimize contour deformities following surgery. Advocates of each technique report results which suggest effectiveness in the prevention of Frey syndrome, however, no evidence-based studies have been conducted which indicate effective long term prevention of the syndrome or a clear preference in which technique offers the greatest benefit. The choice of which procedure to utilize in the reconstitution of the parotid bed will likely be predicated on the size of the defect, experience of the surgeon, and the availability of appropriate allograft material. Similarly, the decision as to whether the parotid gland resection should be limited, in order to reduce the risk of Frey syndrome, will be dependent upon disease extent and pathology, together with surgeon preference and familiarity with partial parotidectomy techniques.
References
Drummond PD
Mechanism of gustatory flushing in Frey's syndrome.
The effectiveness of sternocleidomastoid flap versus superficial musculoaponeurotic system flap for the prevention of Frey syndrome and facial depressed deformity in parotid surgery for pleomorphic adenoma.
Declaration of Competing Interest statements were not included in published version of the following articles that appeared in previous issues of Operative Techniques in Otolaryngology - Head and Neck Surgery. Hence, The authors were contacted after publication to request a Declaration of Interest statement:
30037-X&id=gr1a.jpg){kind=link}
30037-X&id=gr1b.jpg){kind=link}
30037-X&id=gr2a.jpg){kind=link}
30037-X&id=gr2b.jpg){kind=link}
30037-X&id=gr3a.jpg){kind=link}
30037-X&id=gr3b.jpg){kind=link}
30037-X&id=gr4.jpg){kind=link}