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Revista Española de Cirugía Oral y Maxilofacial

On-line version ISSN 2173-9161Print version ISSN 1130-0558

Rev Esp Cirug Oral y Maxilofac vol.28 n.3 Madrid May./Jun. 2006




SMAS flap for the prevention of Frey’s syndrome

Colgajo de SMAS en la prevención del síndrome de Frey



C. Moreno García1, H. Serrano Gil1, F. Monje Gil2, C. Pérez Herrero3, A.J. Morillo Sánchez3, J. Mateo Arias3
J.C. Moreno Vázquez3, L. Ruiz Laza3

1 Médico Residente
2 Jefe de Servicio
3 Médico Adjunto
Servicio de Cirugía Oral y Maxilofacial. Hospital Infanta Cristina. Complejo Hospitalario Universitario de Badajoz, España





Objective. Frey’s syndrome may occur as a complication following parotid gland surgery. The aim of this article is to analyze the prevention of this syndrome after parotid surgery during which a superficial musculoaponeurotic system (SMAS) flap is elevated.
Material and Methods.
A retrospective study is presented of 81 patients who underwent parotid gland surgery in the department of Oral and Maxillofacial Surgery of the Hospital Infanta Cristina, Badajoz, from October 1997 to February 2005.
The most common technique used in our department was the superficial conservative parotidectomy (68%). The most numerous group was made up of patients with SMAS flaps who did not go on to develop Frey’s syndrome, with a total of 56 cases (69%).
We consider carrying out a SMAS flap in parotid surgery appropriate for reducing the frequency with which Frey’s syndrome appears.

Key words: Frey’s syndrome; SMAS flap; Prevention.


Objetivo. El síndrome de Frey puede surgir como complicación tras cirugía de la glándula parótida. Este artículo pretende analizar la prevención de dicho síndrome tras cirugía parotídea cuando se realiza la elevación de un colgajo de sistema músculo aponeurótico superficial (SMAS).
Material y Método.
Presentamos un estudio retrospectivo con 81 pacientes a los que se realizó cirugía sobre la glándula parótida, en el Servicio de Cirugía Oral y Maxilofacial del Hospital Infanta Cristina de Badajoz desde Octubre de 1997 hasta Febrero de 2005.
La técnica más comúnmente realizada en nuestro Servicio fue la parotidectomía superficial conservadora (68%). El grupo más numeroso lo formaron aquellos pacientes en los que se realizó colgajo de SMAS y no desarrollaron posteriormente síndrome de Frey con un total de 56 casos (69%).
Consideramos adecuada la realización de colgajo de SMAS en cirugía parotídea, para disminuir la frecuencia de aparición del síndrome de Frey.

Palabras clave: Síndrome de Frey; Colgajo de SMAS; Prevención.



Frey’s syndrome,1 also known as auriculotemporal nerve syndrome or gustatory sweating syndrome, is characterized by the appearance of erythema and sweating of the skin on the face, normally in the preauricular region, in relation with mastication and swallowing. It has been observed in patients after suffering a parotidectomy, trigeminal herpes zoster, parotiditis, fractures of the mandibular condyle, obstetric trauma with forceps, and surgery of the meningioma of the cerebellopontine angle.2 Incidence after parotid gland surgery is between 30-60%.3 It has been described as a late complication that tends to appear 3-6 months after the surgical intervention.3

The objective of this article is to analyze if preventing the appearance of Frey’s syndrome is possible after the preservation and elevation of a SMAS flap in parotid gland surgery.


Material and method

A retrospective study has been carried out that includes 81 cases of surgery of the parotid gland carried out by the department of Oral and Maxillofacial Surgery of the Hospital Infanta Cristina, Badajoz, between October 1997 and February 2005.

For the diagnosis of Frey’s syndrome, in addition to the clinical symptoms, Minor’s test was used. It consists in applying iodine to the skin, letting it dry, adding a layer of starch and offering the patient a sialogogue to stimulate sweating. This will make the starch mix with the iodine and a conclusively dark color will appear.2, 4

The surgical technique of SMAS is the following: After elevating the flap of skin and subcutaneous cellular tissue, the SMAS of parotid fascia is dissected (Fig. 1). The dissection, as we advance along a more anterior plane, has to be very carefully done so that the branches of the facial nerve underlying the fascia are not damaged. The surgical limit is situated a centimeter below the zygomatic arch, and the lower limit should not be more that a centimeter over the mandibular border. After carrying out the parotidectomy a sub- SMAS drain is placed, the flap is moved in a postero-superior direction, until there is adequate tension. (Fig. 2) The SMAS is then sutured to the lower, middle and upper area of the preauricular tissue (Fig. 3).16



Most of the surgery on the parotid gland that was carried out by our department consisted of superficial conservative parotidectomies (68%), followed by, in descending order, total conservative parotidectomies (19%) tumorectomies (11%) and non-conservative total parotidectomies (2%). Most of the neoplasms operated on had benign histology (91%), as opposed to 9% that were malignant. With regard to complications after parotid surgery, neuroapraxia of the facial nerve was most common (33%), followed by anesthesia/paresthesia of the outer ear (21%), and thirdly Frey’s syndrome with a total of 13 cases (16%) (Table 1).



Of the cases in which Frey’s syndrome was established, 6 had the antecedent of a superficial parotidectomy. In 5 cases it was observed that a total parotidectomy had previously been carried out, and 2 cases occurred after a tumorectomy.

Of the total number of patients operated on, the most numerous group was made up of patients with raised SMAS flaps who did not later develop Frey’s syndrome, with a total of 56 cases (69%). 9 patients (11%), in spite of a SMAS flap, did develop the symptomatology that is characteristic of the syndrome. 12 patients (15%) did not develop Frey’s syndrome and they did not have a SMAS flap. Finally, 4 patients (5%) that had not had a SMAS flap did develop the syndrome. (Fig. 4).



Frey’s syndrome is characterized by the appearance of erythema and sweating of the skin on the face that is related to mastication and swallowing. It is described as a possible complication after parotid surgery. The most accepted hypothesis today as to its origin is that it is an aberrant regeneration of parasympathetic fibers. These fibers in normal conditions accompany the auriculotemporal nerve and they stimulate salivary secretion of the parotid gland. It would seem that damage to these fibers provokes an aberrant regeneration in an inadequate direction, that reaches and stimulates the eccrine sweat glands of the skin as well as the vessels of the dermis, leading to vasodilation.2, 4 The parasympathetic fibers implicated in the physiopathology of the syndrome follow a relatively complex route. They emerge from the inferior salivary bulbar nucleus. They join the glossopharyngeal nerve, pass Jacobson’s nerve, the lesser deep petrosal nerve and they reach the otic ganglion. From this point they accompany the auriculotemporal nerve until they reach the parotid gland.2

Once the syndrome has started, from the point of view of medical treatment and in minor cases, aluminum chloride (roll-on deodorant) has been used as well as anticholinergic agents such as topical glycopyrrolate, atropine or scopolamine.8 Therapy using intradermic botulinum toxin type A is currently growing in importance.6,8

If surgical treatment is needed, once Frey’s syndrome is established, various techniques have been described such as the sectioning of Jacobson’s nerve, the sectioning of the tympanic plexus, removal of the auriculotemporal nerve, alcoholization of the superior cervical ganglion, otic ganglion, tympanic plexus... etc. These techniques obtain stable results, but they are excessively aggressive if compared to the magnitude of the problem.12

The importance of preventing the syndrome’s appearance should be stressed as, once established, the treatment available does not provide totally satisfactory results. With regard to medical treatment, the benefits are temporary, and from the surgical point of view, obtaining stable results will over time entail carrying out aggressive techniques that in most cases are not justified in view of the patient’s symptoms.

Various techniques have been described for preventing the development of Frey’s syndrome after parotid gland surgery.9,11,13-15 One is the preservation and raising of a superficial musculoaponeurotic system SMAS flap.16-22 If carried out by a surgeon with experience, the surgical act will be extended slightly16 and in turn the discomfort that arises when the symptoms of Frey’s syndrome appear can be avoided, as well as medical treatment that has to be repeated periodically or a second surgical act. The use of the SMAS flap as a method for preventing the development of Frey’s syndrome is based on accepting as correct the previously mentioned hypothesis of aberrant regeneration of parasympathetic fibers. The flap is placed between the subcutaneous cell tissue and the parotid bed and it acts as a barrier that will make the progression of the aberrant parasympathetic fibers towards the skin more difficult.

On analyzing the results, we can see that the most numerous group (69%) is formed by those patients that had a SMAS flap and that did not develop the characteristic clinical symptoms of Frey’s syndrome. Nevertheless, 11% of cases did develop this syndrome despite the elevation of a SMAS flap. This could be attributed to an incorrect technique if the flap was not completely preserved and intact, or perhaps in the genesis of the pathological process other unknown and influential etiological factors are not being taken into account.

One should remember that in tumor surgery, if the previous pathological study indicates malignancy, the SMAS should not be preserved. This is also the case with benign tumors that are closely attached to the SMAS plane because of an association with a greater recurrence rate.16



In conclusion, given the experience of our department, and supported by the existing literature on the subject, we consider performing surgical SMAS flaps by the parotid gland appropriate, in order to reduce the frequency with which Frey’s syndrome appears.



Carlos Moreno García
c/ Jacinta García Hernández, Nº 7, Portal 2 5ºE
06011 Badajoz, España

Recibido: 07.07.2005
Aceptado: 04.07.2006




1. Frey L. Le Syndrome du nerf auriculotemporal. Rev Neurol 1923;2:97-9.        [ Links ]

2. Santa Cruz Ruiz S, Muñoz Herrera A, Santa Cruz Ruiz P, Gil Melcon M, Batuecas Caletrio A. Síndrome de Frey idiopático bajo la apariencia de una otitis externa recidivante. Tratamiento con neuro-toxina botulínica tipo A. Acta Otorrinolaringol Esp 2005;56:83-5.        [ Links ]

3. Martín-Granizo R. Manual de Cirugía Oral y Maxilofacial. Ed GlaxoSmithKline 2004;1003.        [ Links ]

4. Labarta N, Olaguibel J.M, Gómez B, Lizaso M, García B, Echechipia S, Tabar A. Síndrome de nervio auriculotemporal. Diagnóstico diferencial con alergia alimentaria. Alergol Inmunol Clin 2002;17:223-6.        [ Links ]

5. Won-Oak K, Hae-Keum K, Duck- Me Y, Min-Jeong C. Treatment of compensatory gustatory hyperhidrosis with topical glycopyrrolate. Yonsey Medical Journal 2003;44:579-82.        [ Links ]

6. Guntinas - Lichius O. Manegement of Frey´s syndrome and hypersialorrhea with botulinum toxin. Facial Plast Surg Clin North Am 2003;11:503-13.        [ Links ]

7. Laskawi R, Ellies M, Rodel R, Schoenebeck C. Gustatory sweting: Clinical implications and etiologic aspects. J Oral Maxillofac Surg 1999;57:642-8; dicusión 648-9.        [ Links ]

8. Kyrmizakis De, Pangalos A, Papadakis CE, Logothetis J, Maroudias NJ, Helidonis ES. The use of botulinum toxin type A in the treatment of Frey and crocodile tears Syndromes. J Oral Maxillofac Surg 2004;62:840-4.        [ Links ]

9. Bonanno PC, Palaia D, Rosenberg M, Casson P. Prophylaxis against Frey´s syndrome in parotid surgery. Ann Plast Surg 2000;44:498-501.        [ Links ]

10. Budzinski R. Frey syndrome: diagnosis and treatment. Otolaryngol Pol 1999; 53:687-91.        [ Links ]

11. Ahmed OA, Kolhe PS. Prevention of Frey´s syndrome and volume deficit after parotidectomy using the superficial temporal artery fascial flap. Br J Plast Surg 1999;52:256-60.        [ Links ]

12. Bozzetti A, Biglioli F, Salvato G, Brusati R. Technical refinements in surgical treatment of benign parotid tumours. Journal Cranio-Maxillofacial Surg 1999; 27:289-93.        [ Links ]

13. Sood S, Quiraishi M, Jennings C, Bradley P. Frey´s syndrome following parotidectomy: prevention using a rotation sternocleidomastoid muscle flap. Clinical Otolaryngology & Allied Sciencies 1999;24:365.        [ Links ]

14. Sinha UK, Saadat D, Doherty CM, Rice DH. Use of Aloderm implant to prevent frey syndrome after parotidectomy. Arch Facial Plast Surg 2003;5:109-12.        [ Links ]

15. Dulguerov P, Quinodoz D, Cosendai G, Piletta P, Marchal F, Lehmann W. Prevention of Frey syndrome during parotidectomy. Arch Otolaryngol Head Neck Surg 1999;125:833-9.        [ Links ]

16. Falahat F, Martín-Granizo R, Berguer A, De Pedro M, Alonso A, Domínguez L. Empleo del colgajo de sistema músculo-aponeurótico superficial (SMAS) en la cirugía de parótida. Rev Esp Cirug Oral y Maxilofac 2002;24:129-35.        [ Links ]

17. Moulton-Barret R, Allison G, Rappaport I.Variaton´s in the use of SMAS to prevent Frey´s syndrome after parotidectomy. Int Surg 1996;81: 174-6.        [ Links ]

18. Belli E, Valentini V, Matteini C. The role of SMAS in the prevention of Frey´s syndrome. Minerva Stomatol 1996;45:569-74.        [ Links ]

19. Bischofberger A, Linder T, Melik N, Schmid S. Indications an efects of the SMAS in parotid surgery. Schweiz Med Wochenschr 2000; Suppl 125:112S-115S.        [ Links ]

20. Angspatt A, Yangyen T, Jindarak S. The role of SMAS flap in preventing Frey’s syndrome follow standard superficial parotidectomy. J Med Assoc Thai 2004;87:624-7.        [ Links ]

21. Taylor SM, Yoo J. Prospective cohort study comparing subcutaneus and sub-superficial musculoaponeurotic system flaps in superficial parotidectomy. J Otolaryngol 2003;32:71-6.        [ Links ]

22. Hoing JF. Facelift approach with a hibrid SMAS rotation advancement flap in parotidectomy for prevention scars and contour deficiency affecting the neck and sweat secretion of the cheek. J Craniofac Surg 2004;15:797-803.        [ Links ]

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