Evaluation of effect of transcutaneous electrical nerve stimulation on salivary flow rate in radiation induced xerostomia patients: a pilot study.

Abstract

Xerostomia is a common sequel in patients undergoing irradiation of malignant tumors of the head and neck. Palliative treatments of xerostomia like topical agents such as ice-chips, saliva substitutes, systemic sialogogues like pilocarpine and cevimeline work well for some patients. Electrostimulation was studied in the past and showed moderate promise but never became part of the mainstream therapy for better management of xerostomia patients. The aim of the following study is to evaluate the effectiveness of a transcutaneous electrical nerve stimulation (TENS) unit in stimulating the whole salivary flow rate in radiation induced xerostomia patients. A total of 40 subjects were included in the study. The study group consisted of 30 individuals and was divided into Group S1 (n = 20), which was further subdivided into Group S1A (n = 10) subjects complaining of dry mouth who were undergoing head and neck radiotherapy with TENS stimulation during the commencement of radiotherapy, on the 3 rd , 6 th week and after a month of completion of radiotherapy and Group S1B (n = 10) with TENS stimulation daily during the full course of radiotherapy and Group S2 (n = 10) subjects complaining of dry mouth who had undergone head and neck radiotherapy that ended 1 month prior to their entry into the study. The control group (n = 10) consisted of healthy individuals not complaining of dry mouth and who have not undergone head and neck radiotherapy. Whole saliva was collected without stimulation for 10 min and after electrostimulation with TENS unit for additional 10 min in a graduated test tube. The results were statistically analyzed using Mann-Whitney U-test and Kruskal-Wallis's test. The data analysis revealed that control and S1B group showed increased salivary flow rate after stimulation by TENS therapy compared with the unstimulated salivary flow, whereas in S1A and S2 group it was found to be statistically non-significant. The present study gave us an insight about the effectiveness of TENS therapy in stimulating salivary flow in healthy subjects and it is very effective when used in conjunction with radiation therapy by reducing the side-effects of radiation therapy. Hence, TENS therapy can be used as an adjunctive method for the treatment of xerostomia along with other treatment modalities.