Frey's syndrome analysis with biosensor. A preliminary study

O. Laccourreye, D. Bernard, O. de Lacharriere, R. Bazin and D. Brasnu
Laboratoire de Recherche Appliquee Voix, Biomateriaux, et Cancerologie ORL, Laennec Hospital, University of Paris, France.

OBJECTIVE: Objective quantification of Frey's syndrome (gustatory sweating), following total parotidectomy. A biosensoring method of enzymatic electrodes enabling the detection of L-lactate on intact skin with the use of a skin extraction device and enzymatic electrodes is presented and analyzed. DESIGN: A criterion standard study. SETTING: This prospective trial was undertaken at our research laboratory (University of Paris [France]). Parotidectomy was performed in our department, which is a tertiary care center for parotid gland pathology. PATIENTS: Twenty-eight patients with gustatory sweating following total parotidectomy and nine control patients not operated on were asked to take part in this prospective study. MAIN OUTCOME AND MEASURES: Gustatory sweating was assessed in all patients using a clinical scale, the Minor starch iodine test, and the L-lactate biosensoring method. RESULTS: Instrumentation and assay procedure for the L-lactate biosensoring method are detailed. Statistical analysis of data was performed using the Kruskal-Wallis H Test and the Mann-Whitney U Test. Results demonstrate that this method enables objective measurement of the L-lactate on skin without the need for chemical reagents, continuous nondestructive analysis in real time, and physiological dynamic monitoring of the L-lactate rate of production after stimulus. Data achieved strongly suggested that the aberrant regeneration theory is the main clue to Frey's syndrome pathogenesis. CONCLUSION: This safe, reliable, noninvasive, objective, and highly sensitive method provides an investigative tool for clinicians as well as physiologists involved with patients presenting gustatory sweating following parotid gland surgery.