Original Article
Evaluation of effect of transcutaneous electrical nerve stimulation on salivary flow rate in radiation induced xerostomia patients: A pilot study ABSTRACT Context: 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. Aims: 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. Materials and Methods: 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 3rd, 6th 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. Results: 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. Conclusion: 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. KEY WORDS: Radiation therapy, salivary flow, transcutaneous electrical nerve stimulation
INTRODUCTION “You will never miss the water until the well runs dry”. How true this is, especially for saliva. Saliva is the physiological fluid of the oral cavity. It is a multipurpose fluid as it keeps the mouth moist, cleanses the oral cavity, facilitates speech, lubricates food for chewing and swallowing, aids in full appreciation of taste sensation, helps in digestion, acts as a buffering agent to neutralize acid attack of bacteria, acts as an antimicrobial agent, mineralizes the teeth.[1] Xerostomia is the symptom of oral dryness resulting from decreased salivary flow. The main causes of xerostomia are medications, radiation therapy of
head and neck cancers and autoimmune disorders such as Sjogren’s syndrome.[2] Because salivary glands are radiosensitive, hyposalivation is a common sequel in patients undergoing irradiation of malignant tumors of the head and neck. There is extensive evidence that the irradiation volume of the salivary glands and the total radiotherapy dose strongly influence the extent of salivary dysfunction after irradiation.[1,2]
Anusha Rangare Lakshman, G. Subhas Babu1, Suresh Rao2 Departments of Oral Medicine and Radiology, Century International Institute of Dental Science and Research Centre, Poinachi, Kasaragod, Kerala, 1A.B. Shetty Memorial Institute of Dental Sciences, Deralakatte, 2 Department of Radiation Oncology Division, Mangalore Institute of Oncology, Mangalore, Karnataka, India For correspondence: Dr. Anusha Rangare Lakshman, Department of Oral Medicine and Radiology, Century International Institute of Dental Science and Research Centre, Poinachi, Kasaragod ‑ 671 541, Kerala, India. E‑mail: dr.anusharl@ gmail.com
Access this article online Website: www.cancerjournal.net DOI: 10.4103/0973-1482.138008 PMID: ***
Palliative treatments of xerostomia include topical agents such as ice‑chips and saliva substitutes, increasing water intake, applying lip balm, chewing sugar free gum, paraffin and citric acid containing lozenges and rinses.[3] Systemic sialogogues such as pilocarpine and cevimeline stimulate salivary
Journal of Cancer Research and Therapeutics - January-March 2015 - Volume 11 - Issue 1
Quick Response Code:
229
Lakshman, et al.: Effect of TENS on salivary flow
flow, but often have unfavorable side‑effects such as profuse sweating, rhinitis, dyspepsia. Acupuncture also has shown improvement in xerostomic and healthy patients.[3,4] Transcutaneous electrical nerve stimulation (TENS) is a well‑known physical therapy, which is useful for the relief of pain. With TENS, electrical stimulation is directed to chronic pain areas via surface electrodes and current passed through these areas reduces or eliminates pain.[5] It is non‑invasive, safe and easy to master and generally well‑accepted by the patients.[3] It is widely used to relieve various types of conditions such as low back pain, myofascial and arthritic pain, bladder incontinence, neurogenic pain, visceral pain and post‑surgical pain.[6] Electrostimulation was studied in the past and showed moderate promise, but never became part of the mainstream therapy for better management of xerostomia patients and Sjogren’s syndrome.[7] The results of preliminary investigations of non‑invasive electronic stimulation of reflex salivation in xerostomic patients have been encouraging.[3,8]
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. Ethical committee clearance and prior informed consent of all the subjects was obtained before conducting the study. For study group S1A and S1B patient’s salivary samples are collected before the commencement of head and neck radiotherapy and during radiotherapy on 3rd and 6th week and after 1 month of the completion of radiotherapy. For study group S2 patient’s salivary samples are collected after 1 month of head and neck radiotherapy. All the subjects are asked to refrain from eating, drinking and chewing gum, smoking or oral hygiene procedures for at least 1 h prior to the appointment. The whole saliva was collected using spit method for 10 min.
An original investigation using non‑invasive electrical stimulation for treatment and prevention of radiation side‑effects in patients undergoing radiotherapy for carcinoma of head and neck showed promising results.[9] Research in this area has been sparse and hence this study was undertaken to evaluate the effectiveness of a TENS unit in stimulating the whole salivary flow rate in radiation induced xerostomia patients.
TENS unit The apparatus used is a strong low rate conventional mode of TENS model‑NS Electro pulse that generates current through AC at a continuous frequency of 500 Hz with a sweep of 0.5‑2 Hz. It consists of two primary components the central control unit and electrode pads. The electrodes are placed externally on the skin overlying the parotid glands with the TENS unit in the off position [Figure 1].
The objectives of our study were as follows: • To evaluate the effectiveness of TENS unit in stimulating whole salivary flow rate in healthy subjects, in patients undergoing head and neck radiotherapy, in patients who have undergone head and neck radiotherapy • To compare the effectiveness of TENS unit in stimulating whole salivary flow rate in healthy subjects, patients undergoing head and neck radiotherapy and patients who have undergone head and neck radiotherapy.
Then the TENS unit is activated under continuous mode and intensity control switch is adjusted for 5 min for patient’s comfort. Then stimulated whole saliva is collected for 10 min in a separate glass beaker. Any increase in salivary flow with electrostimulation, per individual subjects is considered a positive finding. Mann‑Whitney U‑test was applied to statistically determine significant difference within the groups and Kruskal‑Wallis’s
MATERIALS AND METHODS The present study was a randomized case control study conducted on patients who have been undergoing radiation therapy for head and neck cancer in Department of Radiation Oncology at Father Muller Medical College, Kankanady, Mangalore. A total of 40 subjects were included in the study. The study group consisted of 30 individuals and were 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 3rd, 6th week and after a month of completion of radiotherapy and Group S1B (n = 10) with TENS stimulation daily during 230
Figure 1: The extraoral transcutaneous electrical nerve stimulation unit
Journal of Cancer Research and Therapeutics - January-March 2015 - Volume 11 - Issue 1
Lakshman, et al.: Effect of TENS on salivary flow
test was applied to determine significant difference between the groups. RESULTS When Mann‑Whitney U‑test was used to compare the unstimulated and stimulated salivary flow rate in each group, the values were very highly significant for the control group; for S1A group at the beginning of radiation therapy was significant and 3rd week, 6th week and after a month was non‑significant; S1B group at the beginning of radiation therapy, 3rd week, 6th week and after a month was highly significant; for S2 group was non‑significant. The values of mean with a standard deviation, median and range of unstimulated and stimulated salivary flow rate were calculated for all the 4 groups and are given in Table 1 and Graph 1. Comparison of unstimulated and stimulated salivary flow rate between the study group S1A and S1B at the beginning of radiotherapy was found to be non‑significant, 3rd week was found to be significant, 6th week was significant and after a month was very highly significant [Table 2 and Graph 2]. Kruskal‑Wallis’s test was applied to determine significant difference between the groups, which was found to be non‑significant when comparison of unstimulated and stimulated salivary flow rate between the control and study groups (S1 and S2) [Table 3 and Graph 3]. DISCUSSION In the present study, the control group showed increased salivary flow rate after stimulation by TENS therapy compared to the unstimulated salivary flow which was in agreement with study by Hargitai et al.[3] in which 15 (out of 22) healthy subjects demonstrated a significant increase in the parotid salivary flow and the maximum increase was 8.75 fold greater than the baseline.
In a study by Saraf et al.[10] showed that 85 of hundred healthy subjects demonstrated increased salivary flow when stimulated via the TENS unit. And also in a study by Weiss et al.[8] who reported the use of an electronic stimulator as a method for increasing salivary production. Following a visual Table 1: Comparison between unstimulated and stimulated salivary flow rate in each group Group weeks Class
N
Control
10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
S1A
S1B
S2
0 week 3rd week 6th week After a month 0 week 3rd week 6th week After a month After a month
Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated
Mean Standard deviation 0.6100 0.19143 1.6500 0.46963 0.5860 0.34526 1.2300 0.57937 0.3430 0.16700 0.4290 0.17375 0.2910 0.19936 0.3650 0.23543 0.3320 0.11555 0.3850 0.12852 0.8480 0.29728 1.6200 0.40770 0.5600 0.21187 1.3800 0.13166 0.7000 0.26179 1.2720 0.28098 0.8260 0.23590 1.6400 0.47422 0.5580 0.46804 0.579 0.41356
Z 3.79800 P
Evaluation of effect of transcutaneous electrical nerve stimulation on salivary flow rate in radiation induced xerostomia patients: A pilot study ABSTRACT Context: 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. Aims: 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. Materials and Methods: 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 3rd, 6th 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. Results: 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. Conclusion: 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. KEY WORDS: Radiation therapy, salivary flow, transcutaneous electrical nerve stimulation
INTRODUCTION “You will never miss the water until the well runs dry”. How true this is, especially for saliva. Saliva is the physiological fluid of the oral cavity. It is a multipurpose fluid as it keeps the mouth moist, cleanses the oral cavity, facilitates speech, lubricates food for chewing and swallowing, aids in full appreciation of taste sensation, helps in digestion, acts as a buffering agent to neutralize acid attack of bacteria, acts as an antimicrobial agent, mineralizes the teeth.[1] Xerostomia is the symptom of oral dryness resulting from decreased salivary flow. The main causes of xerostomia are medications, radiation therapy of
head and neck cancers and autoimmune disorders such as Sjogren’s syndrome.[2] Because salivary glands are radiosensitive, hyposalivation is a common sequel in patients undergoing irradiation of malignant tumors of the head and neck. There is extensive evidence that the irradiation volume of the salivary glands and the total radiotherapy dose strongly influence the extent of salivary dysfunction after irradiation.[1,2]
Anusha Rangare Lakshman, G. Subhas Babu1, Suresh Rao2 Departments of Oral Medicine and Radiology, Century International Institute of Dental Science and Research Centre, Poinachi, Kasaragod, Kerala, 1A.B. Shetty Memorial Institute of Dental Sciences, Deralakatte, 2 Department of Radiation Oncology Division, Mangalore Institute of Oncology, Mangalore, Karnataka, India For correspondence: Dr. Anusha Rangare Lakshman, Department of Oral Medicine and Radiology, Century International Institute of Dental Science and Research Centre, Poinachi, Kasaragod ‑ 671 541, Kerala, India. E‑mail: dr.anusharl@ gmail.com
Access this article online Website: www.cancerjournal.net DOI: 10.4103/0973-1482.138008 PMID: ***
Palliative treatments of xerostomia include topical agents such as ice‑chips and saliva substitutes, increasing water intake, applying lip balm, chewing sugar free gum, paraffin and citric acid containing lozenges and rinses.[3] Systemic sialogogues such as pilocarpine and cevimeline stimulate salivary
Journal of Cancer Research and Therapeutics - January-March 2015 - Volume 11 - Issue 1
Quick Response Code:
229
Lakshman, et al.: Effect of TENS on salivary flow
flow, but often have unfavorable side‑effects such as profuse sweating, rhinitis, dyspepsia. Acupuncture also has shown improvement in xerostomic and healthy patients.[3,4] Transcutaneous electrical nerve stimulation (TENS) is a well‑known physical therapy, which is useful for the relief of pain. With TENS, electrical stimulation is directed to chronic pain areas via surface electrodes and current passed through these areas reduces or eliminates pain.[5] It is non‑invasive, safe and easy to master and generally well‑accepted by the patients.[3] It is widely used to relieve various types of conditions such as low back pain, myofascial and arthritic pain, bladder incontinence, neurogenic pain, visceral pain and post‑surgical pain.[6] Electrostimulation was studied in the past and showed moderate promise, but never became part of the mainstream therapy for better management of xerostomia patients and Sjogren’s syndrome.[7] The results of preliminary investigations of non‑invasive electronic stimulation of reflex salivation in xerostomic patients have been encouraging.[3,8]
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. Ethical committee clearance and prior informed consent of all the subjects was obtained before conducting the study. For study group S1A and S1B patient’s salivary samples are collected before the commencement of head and neck radiotherapy and during radiotherapy on 3rd and 6th week and after 1 month of the completion of radiotherapy. For study group S2 patient’s salivary samples are collected after 1 month of head and neck radiotherapy. All the subjects are asked to refrain from eating, drinking and chewing gum, smoking or oral hygiene procedures for at least 1 h prior to the appointment. The whole saliva was collected using spit method for 10 min.
An original investigation using non‑invasive electrical stimulation for treatment and prevention of radiation side‑effects in patients undergoing radiotherapy for carcinoma of head and neck showed promising results.[9] Research in this area has been sparse and hence this study was undertaken to evaluate the effectiveness of a TENS unit in stimulating the whole salivary flow rate in radiation induced xerostomia patients.
TENS unit The apparatus used is a strong low rate conventional mode of TENS model‑NS Electro pulse that generates current through AC at a continuous frequency of 500 Hz with a sweep of 0.5‑2 Hz. It consists of two primary components the central control unit and electrode pads. The electrodes are placed externally on the skin overlying the parotid glands with the TENS unit in the off position [Figure 1].
The objectives of our study were as follows: • To evaluate the effectiveness of TENS unit in stimulating whole salivary flow rate in healthy subjects, in patients undergoing head and neck radiotherapy, in patients who have undergone head and neck radiotherapy • To compare the effectiveness of TENS unit in stimulating whole salivary flow rate in healthy subjects, patients undergoing head and neck radiotherapy and patients who have undergone head and neck radiotherapy.
Then the TENS unit is activated under continuous mode and intensity control switch is adjusted for 5 min for patient’s comfort. Then stimulated whole saliva is collected for 10 min in a separate glass beaker. Any increase in salivary flow with electrostimulation, per individual subjects is considered a positive finding. Mann‑Whitney U‑test was applied to statistically determine significant difference within the groups and Kruskal‑Wallis’s
MATERIALS AND METHODS The present study was a randomized case control study conducted on patients who have been undergoing radiation therapy for head and neck cancer in Department of Radiation Oncology at Father Muller Medical College, Kankanady, Mangalore. A total of 40 subjects were included in the study. The study group consisted of 30 individuals and were 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 3rd, 6th week and after a month of completion of radiotherapy and Group S1B (n = 10) with TENS stimulation daily during 230
Figure 1: The extraoral transcutaneous electrical nerve stimulation unit
Journal of Cancer Research and Therapeutics - January-March 2015 - Volume 11 - Issue 1
Lakshman, et al.: Effect of TENS on salivary flow
test was applied to determine significant difference between the groups. RESULTS When Mann‑Whitney U‑test was used to compare the unstimulated and stimulated salivary flow rate in each group, the values were very highly significant for the control group; for S1A group at the beginning of radiation therapy was significant and 3rd week, 6th week and after a month was non‑significant; S1B group at the beginning of radiation therapy, 3rd week, 6th week and after a month was highly significant; for S2 group was non‑significant. The values of mean with a standard deviation, median and range of unstimulated and stimulated salivary flow rate were calculated for all the 4 groups and are given in Table 1 and Graph 1. Comparison of unstimulated and stimulated salivary flow rate between the study group S1A and S1B at the beginning of radiotherapy was found to be non‑significant, 3rd week was found to be significant, 6th week was significant and after a month was very highly significant [Table 2 and Graph 2]. Kruskal‑Wallis’s test was applied to determine significant difference between the groups, which was found to be non‑significant when comparison of unstimulated and stimulated salivary flow rate between the control and study groups (S1 and S2) [Table 3 and Graph 3]. DISCUSSION In the present study, the control group showed increased salivary flow rate after stimulation by TENS therapy compared to the unstimulated salivary flow which was in agreement with study by Hargitai et al.[3] in which 15 (out of 22) healthy subjects demonstrated a significant increase in the parotid salivary flow and the maximum increase was 8.75 fold greater than the baseline.
In a study by Saraf et al.[10] showed that 85 of hundred healthy subjects demonstrated increased salivary flow when stimulated via the TENS unit. And also in a study by Weiss et al.[8] who reported the use of an electronic stimulator as a method for increasing salivary production. Following a visual Table 1: Comparison between unstimulated and stimulated salivary flow rate in each group Group weeks Class
N
Control
10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
S1A
S1B
S2
0 week 3rd week 6th week After a month 0 week 3rd week 6th week After a month After a month
Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated Unstimulated Stimulated
Mean Standard deviation 0.6100 0.19143 1.6500 0.46963 0.5860 0.34526 1.2300 0.57937 0.3430 0.16700 0.4290 0.17375 0.2910 0.19936 0.3650 0.23543 0.3320 0.11555 0.3850 0.12852 0.8480 0.29728 1.6200 0.40770 0.5600 0.21187 1.3800 0.13166 0.7000 0.26179 1.2720 0.28098 0.8260 0.23590 1.6400 0.47422 0.5580 0.46804 0.579 0.41356
Z 3.79800 P
