Scintigraphy in prediction of the submandibular salivary gland function after chorda tympani damage

الملخص EN

The nerve supply to the submandibular glands is via the facial nerve, specially the chorda tympani transmitting afferent sensory and efferent secretory impulses.

The aim of this study is to assess the result of chorda tympani damage during middle ear surgery on submandibular gland function using dynamic scintigraphy by comparing between a denervated submandibular gland with the contra-lateral normal side in patients with unilateral chorda tympani damage.

Patients and Methods: 19 patients (11 women and 8men) mean age of (49.6±9.8) years with proven chorda tympani damage during their previous middle ear surgery were included in the study.

The time of chorda tympani damage ranged from (6 to 79) months mean of (50.9 ± 23.9) months.

Our patients were grouped into two groups according to time of postoperative follow-up.

Group I consisted of 10 patients with their follow-up period of 6 months or more.

Group II consisted of 9 patients their follow-up was 60 months or more.

Ultrasonographic measurement of the submandibular gland volume in (ml) was done and the results on both sides were compared to examine for glandular atrophy on the affected side.

The perfusion ratio (PR), concentration ratio (CR) and stimulated excretion ratio (SER) were calculated scintigraphically and the results from the salivary gland on both sides were compared.

Results: For submandibular glands, the mean perfusion ratio (PR), mean concentration ratio (CR) and mean stimulated excretion ratio (SER) were found to be [0.85, 0.90, and 0.91] respectively in group (I) and to be [0.78, 0.87, and 0.89] in group (II).

All ratios resulted from decreased radioactivity accumulation on the affected side.

Using B-mode ultrasonography, the glands on the contralateral, non operated side were found to be significantly (P< 0.05) greater than the ipsilateral, denervated glands as regard the volume in group (II), While, no significant increase in volume of the non-denervated gland were encountered in group (I). Conclusion: Chorda tympani damage negatively affects the function of the ipsilateral submandibular gland despite the absence of atrophy.

Dynamic submandibular gland scintigraphy is a practical and valuable method of disclosing the decreased capacity of perfusion, concentration and secretion in unilateral neurological denervation.

Using B-mode ultrasonography , the late (>60 months) results of chorda tympani damage on submandibular gland were significant for increase in the volume of the contralateral, non denervated gland .

An atrophing effect was not ascertained in the submandibular glands denervated parasympathetically due to section of the chorda tympani.

Elderly and patient scheduled for radiotherapy for Head and Neck cancer, whom chorda tympani was previously damaged must be dealt with, cautiously.