Surgery of the major salivary glands and its impact on salivary flow-A review

A prospective study of patient-reported xerostomia-related outcomes after parotidectomy

OBJECTIVE

There is a paucity of data on patient-reported outcome measures regarding xerostomia after parotidectomy surgery. Although salivary flow rates after parotidectomy have been previously studied, they do not correlate with subjective xerostomia. This study was designed to evaluate if unilateral parotidectomy increases patient-reported xerostomia.

METHODS

A prospective cohort of patients undergoing unilateral partial, superficial, or total parotidectomy for benign or low-grade malignant pathology without postoperative radiation at a tertiary care academic center was studied. We analyzed patient-reported outcome measures of xerostomia using the Xerostomia Questionnaire (XQ) preoperatively and postoperatively. We compared pre- and postoperative cumulative and individual XQ scores using Wilcoxon signed-rank tests. We stratified patients by the weight in grams (g) of the parotid tissue excised, pathology, smoking status, and xerostomia-related medication use.

RESULTS

Twenty-two adults with benign or low grade malignant unilateral parotid tumors were included. Postoperative questionnaires were completed at a median of 10.2 months (interquartile range [IQR] 8.6-11.9) after unilateral parotidectomy. Mean preoperative and postoperative cumulative XQ scores, on a 100-point scale, with higher scores representing worse symptoms, were 10.33 (95% CI: 4.46-16.20) and 10.54 (95% CI: 5.10-15.98), respectively, with a mean change of +0.21 (p = 0.472). There were no statistically significant changes in individual XQ symptom scores. Neither type of parotidectomy, resection specimens weighing over 10 g, smoking habits, xerostomia-related medication use, nor malignant pathology were associated with worse symptom scores.

CONCLUSION

Based on these data, unilateral parotidectomy does not appear to definitely, or at least consistently, increase xerostomia per patient reporting. More extensive parotid resections are not associated with worse symptom scores. These data can help guide preoperative counseling and postoperative expectations for parotidectomy.

LEVEL OF EVIDENCE

2b.

Investigation of Cellular Function and DNA Integrity during 2D in vitro Culture of Human Salivary Gland Epithelial Cells

In vitro culture of human salivary gland epithelial cells (SGEC) is still a challenge. A high quantity and quality of cells are needed for the cultivation of 3D matrices. Furthermore, it is known that DNA damage is supposed to be an important factor involved in carcinogenesis. This study investigates cellular function and DNA integrity of human SGEC during 3 passage steps in 2 groups (group 1: n = 10; group 2: n = 9). Cellular function was analyzed by immunofluorescence, transmission electron microscopy (TEM), and quantitative real-time polymerase chain reaction (qPCR). DNA integrity was tested via the comet assay. Immunohistochemistry and qPCR results showed stable α-amylase and pan-cytokeratin levels; TEM revealed functional cells; and no significant DNA damage could be detected in the comet assay during 3 culture steps. The study shows that not only at cellular but also at DNA level human SGEC can be safely quantified over 3 passages for preclinical tissue engineering without loss of differentiation and function.