Spontaneous tissue regeneration of the Stensen duct in dogs

The use of methylene blue to assist with parotid sialadenectomy in dogs

INTRODUCTION

There is an important morbidity associated with parotidectomy. The most commonly reported permanent complication is facial nerve injury. Methylene blue staining has been used as an intra-operative tool to improve tissue visualisation and preserve facial nerve integrity.

OBJECTIVES

To describe the functionality and feasibility of the use of methylene blue for parotidectomy in dogs.

MATERIALS AND METHODS

Retrospective study included seven client-owned dogs that underwent parotidectomy after injection of methylene blue from 2016 to 2019 in a referral centre. Cross-sectional imaging was used to confirm parotid gland surgical disease and for staging purposes. All dogs underwent parotid resection and removal of the parotid duct after injection of methylene blue. Methylene blue was either administered via cannulation of the parotid duct or directly injected into the abnormal gland.

RESULTS

In all cases, the gland stained dark blue within seconds without any evident leakage. Complete parotid gland resection and removal of the parotid duct was achieved successfully in all dogs with a mean surgical time of 97 minutes. Subjectively, the staining was useful to identify innervation outside the coloured gland and facilitated dissection. No complications, including facial nerve injury, were recorded.

CLINICAL SIGNIFICANCE

Methylene blue staining for complete parotidectomy was feasible, rapid and easy in these dogs. It can be used as an indirect facial nerve identification technique, and can therefore facilitate dissection and possibly reduce the incidence of post-operative facial nerve paralysis.

Chronic alcohol consumption promotes alterations on salivary gland regeneration process

The aim of this study is to investigate the histological effect of alcohol ingestion on the regeneration of the submandibular gland (SMG) in rats. Twelve 60-day-old male Wistar rats were randomized into two experimental groups. Test group (TG) animals ingested 40° GL of alcohol for 45 days before surgery, being its concentration gradually increased 10° GL/week for 4 weeks to achieve the final concentration of 40° GL. The control group (CG) received water during the whole experimental period. One-third of the left SMG lobe was removed. Three and seven days after, the whole gland was excised and analyzed. In the TG, the inflammatory process was pronounced when comparing the CG on day 3. The inverse aspect was observed on day 7, associated with an advanced parenchyma development. Changes in laminin expression and glycoproteins production were observed in the TG, causing advanced morphogenesis and delay in cytodifferentiation during the salivary gland regeneration, probably due to alcohol effects. Animals who received ethanol showed alterations in the pattern of glandular regeneration.