Frey-Syndrom nach lateraler Parotidektomie

[The incidence of Frey syndrome following parotidectomy: results of a survey and follow-up]

BACKGROUND

Frey's syndrome (FS) is defined as facial sweating due to gustatory stimuli following surgery or trauma of the parotid gland. Concomitant symptoms may occur in the area of the auriculotemporal nerve: swelling, facial flushing, and paresthesia. A misguided re-innervation of perspiratory glands by secretory parasympathetic fibres is likely responsible in the pathogenesis. The reported incidence in the literature varies considerably from 1.7% to 97.6%. The present study aims to clarify the incidence of FS.

PATIENTS AND METHODS

A questionnaire was sent to 221 consecutive patients who underwent parotidectomy between 07/2005 and 07/2008. No selection for type of parotidectomy or histological result was made. Patients were invited to undergo a follow-up examination including Minor's iodine starch test.

RESULTS

A total of 135 of 221 (61%) questionnaires were available for evaluation. In all, 82 patients took part in the follow-up, with a follow-up period of 2.8 years (15-51 months). According to the questionnaire, 54% of patients claimed to be free of symptoms. Sweating following gustatory stimuli was reported by 23% of patients. Of the 82 Minor's tests performed, 62.2% were positive. All patients with subjective presence of FS had a positive Minor's test. In 27%, Minor's test was positive although patients did not suffer from facial sweating subjectively ("subclinical FS"). In all, 39% had no subjective complaints and Minor's test was also negative. Cases with a positive Minor's test showed no statistically significant relation to the patients' age, gender or to the histological diagnosis or type of parotidectomy.

CONCLUSION

The clinical incidence of FS in our study is 23%, although a positive Minor's iodine starch test was observed in 62% of cases. Therefore, it seems justifiable to differentiate between a symptomatic or clinical FS and a merely asymptomatic or subclinical FS. No correlation was observed between epidemiological factors and the occurrence of FS.

Management of Frey syndrome

Almost all patients who undergo parotidectomy will to some extent develop Frey syndrome (auriculotemporal syndrome or gustatory sweating) after surgery, because of aberrant regeneration of cut parasympathetic fibers between otic ganglion and subcutaneous vessels. However, only the minority of these patients needs treatment. The syndrome consists of gustatory sweating, flushing, and warming over the preauricular and temporal areas. Thick skin flap and partial superficial parotidectomy are the most important techniques to minimize the risk of developing symptomatic Frey syndrome. Intracutaneous injection of botulinum toxin A is an effective, long-lasting, and well-tolerated treatment of Frey syndrome. If recurrence occurs, the treatment can be repeated.

Morbidity of parotid gland surgery: results 1 year post-operative

Patients operated on for parotid gland tumours were evaluated prospectively to study morbidity after this procedure. Nowadays, major complications such as recurrence of tumour and permanent facial nerve paresis are rare after primary surgery. Therefore, this study especially takes minor complications such as Frey's syndrome and sensory deficits into account. The study documents morbidity in 45 patients who completed a 1 year follow-up. Among those with primary benign tumours, we found no recurrences and no permanent paresis, nor did starch-iodine testing reveal any cases of Frey's syndrome. However, two patients who had previously been operated on multiple times did test positive for Frey's syndrome, as did two others after surgery for malignancy. Furthermore, we found that patients whose posterior branch of the great auricular nerve was sacrificed had a larger area of sensory deficit than those whose nerve was preserved. We conclude that the morbidity of parotid gland surgery can be reduced further by giving minor complications more attention.

Botulinumtoxin zur Behandlung des gustatorischen Schwitzens

BACKGROUND

Botulinum toxin A has meanwhile become a proven method for treatment of gustatory sweating (focal hyperhidrosis, Frey's syndrome). Clear-cut recommendations regarding dosage of botulinum toxin A in Frey's syndrome are currently not available. The aim of this prospective randomized study therefore was to investigate botulinum toxin A with respect to its efficacy in Frey's syndrome, the ideal dose yielding maximal duration of the effect, and patient contentedness as well as unwanted side effects in patients of the Clinic of OMF Surgery at the Ruhr-University of Bochum.

PATIENTS AND METHOD

Twenty patients suffering from severe Frey's syndrome as a result of operations of the parotid gland were examined with the starch iodine test according to Minor. The gustatory skin areas were re-examined after intracutaneous injection of botulinum toxin A for up to 1 year. The patients ( n=20) were randomly assigned to two different treatment groups (group I: 2 MU/cm(2), n=10; group II: 3 MU/cm(2), n=10).

RESULTS

Mean sweating skin areas in the two treatment groups ranged between 39+/-9 and 32+/-12 cm(2), respectively. A single injection of 3 MU botulinum toxin A resulted in a nearly complete blockade of gustatory sweating for the observation period of 1 year. In the group treated with 2 MU botulinum toxin A, 44% of the total gustatory skin areas were still sweating, thus necessitating a second injection of botulinum toxin A in these patients.

CONCLUSION

Intracutaneous injection of botulinum toxin A represents a highly effective and minimally invasive procedure for the treatment of Frey's syndrome. This study shows for the first time that a dosage of 3 MU/cm(2) of botulinum toxin A achieves a complete and reliable blockade of gustatory sweating lasting for at least 12 months. This dose may therefore be recommended for treatment of this syndrome.

Management of Frey's syndrome and hypersialorrhea with botulinum toxin

Botulinum toxin (BTX) is a safe and reliable drug for the treatment of Frey's syndrome and hypersialorrhea. Currently, the intradermal injection of BTX is the standard treatment of Frey's syndrome. A disappearance of Frey's syndrome for 1 to 1.5 year could almost be promised. Recently, BTX was introduced for the treatment of hypersialorrhea. Although some questions exist about the optimal dosage and the type of major salivary glands that should be treated, hypersialorrhea was reduced in almost all affected children and adults for up to 6 months by using ultrasound-guided intraglandular BTX injections.